diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..8517edc
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,2 @@
+*.cmd text eol=crlf
+*.bat text eol=crlf
diff --git a/.gitignore b/.gitignore
index c561d09..3f78207 100644
--- a/.gitignore
+++ b/.gitignore
@@ -21,6 +21,8 @@ third_party/busybox/busybox
 third_party/busybox/busybox.exe
 third_party/curl/
 third_party/PDCurses/
+third_party/ncurses-*/
+third_party/ncurses-*.tar.gz
 third_party/busybox-w32/
 third_party/busybox-src/
 third_party/prefix-mingw/
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5d4a218..abdb70e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,6 +8,32 @@ option(CST_BUILD_TUI "Build ncurses/PDCurses TUI" ON)
 option(CST_NATIVE_ARCH "Pass -march=native to sashidown" OFF)
 option(CST_BUNDLE_BUSYBOX "Install placeholder/scripts for busybox beside binary" ON)
 
+if(WIN32)
+  enable_language(RC)
+  # Cross builds link libgcc/winpthreads/curl statically; MSYS2's curl is a DLL.
+  if(CMAKE_CROSSCOMPILING)
+    set(_CST_STATIC_DEFAULT ON)
+  else()
+    set(_CST_STATIC_DEFAULT OFF)
+  endif()
+  option(CST_WIN_STATIC "Link Windows executables with -static" ${_CST_STATIC_DEFAULT})
+endif()
+
+# Windows: UTF-8 manifest (activeCodePage, longPathAware) and version resource
+# on every executable, so tests run with the same process code page as the app.
+function(cst_win_exe t)
+  if(NOT WIN32)
+    return()
+  endif()
+  target_sources(${t} PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/res/windows/cst-agent.rc")
+  target_include_directories(${t} PRIVATE
+    "${CMAKE_CURRENT_SOURCE_DIR}/include" "${CMAKE_CURRENT_SOURCE_DIR}/res/windows")
+  target_compile_definitions(${t} PRIVATE _WIN32_WINNT=0x0A00)
+  if(CST_WIN_STATIC)
+    target_link_options(${t} PRIVATE -static)
+  endif()
+endfunction()
+
 set(SD_DIR "${CMAKE_CURRENT_SOURCE_DIR}/vendor/sashidown")
 if(CST_NATIVE_ARCH)
   set(_SD_MAKE_EXTRA CST_NATIVE_ARCH=1)
@@ -15,6 +41,9 @@ else()
   set(_SD_MAKE_EXTRA "")
 endif()
 
+# sashidown has a plain Makefile; CMAKE_MAKE_PROGRAM may be ninja.
+find_program(CST_MAKE NAMES make gmake mingw32-make REQUIRED)
+
 # Separate archive for MinGW so Linux host builds keep libsashidown.a
 if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
   set(SASHIDOWN_A "${SD_DIR}/libsashidown-mingw.a")
@@ -26,19 +55,19 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
   set(_MINGW_RANLIB "${CMAKE_RANLIB}")
   add_custom_command(
     OUTPUT "${SASHIDOWN_A}"
-    COMMAND ${CMAKE_MAKE_PROGRAM} -C "${SD_DIR}" clean
-    COMMAND ${CMAKE_MAKE_PROGRAM} -C "${SD_DIR}" libsashidown.a
+    COMMAND ${CST_MAKE} -C "${SD_DIR}" clean
+    COMMAND ${CST_MAKE} -C "${SD_DIR}" libsashidown.a
             CC=${CMAKE_C_COMPILER} AR=${_MINGW_AR} RANLIB=${_MINGW_RANLIB}
     COMMAND ${CMAKE_COMMAND} -E copy_if_different
             "${SD_DIR}/libsashidown.a" "${SASHIDOWN_A}"
-    COMMAND ${CMAKE_MAKE_PROGRAM} -C "${SD_DIR}" clean
+    COMMAND ${CST_MAKE} -C "${SD_DIR}" clean
     COMMENT "Building libsashidown for MinGW"
     VERBATIM)
 else()
   set(SASHIDOWN_A "${SD_DIR}/libsashidown.a")
   add_custom_command(
     OUTPUT "${SASHIDOWN_A}"
-    COMMAND ${CMAKE_MAKE_PROGRAM} -C "${SD_DIR}" libsashidown.a CC=${CMAKE_C_COMPILER} ${_SD_MAKE_EXTRA}
+    COMMAND ${CST_MAKE} -C "${SD_DIR}" libsashidown.a CC=${CMAKE_C_COMPILER} ${_SD_MAKE_EXTRA}
     COMMENT "Building libsashidown.a"
     VERBATIM)
 endif()
@@ -54,6 +83,7 @@ set(CST_CORE_SOURCES
   src/util.c
   src/ctl_parse.c
   src/os_compat.c
+  src/os_win.c
   src/sandbox.c
   src/sandbox_exec.c
   src/keymap.c
@@ -82,6 +112,14 @@ set(CST_CORE_SOURCES
   src/models.c
   src/metrics.c
 )
+if(WIN32)
+  # MinGW has no <regex.h>: musl's TRE engine, UTF-8 aware (vendor/tre-regex)
+  include_directories(vendor/tre-regex)
+  list(APPEND CST_CORE_SOURCES
+    vendor/tre-regex/regcomp.c vendor/tre-regex/regexec.c
+    vendor/tre-regex/regerror.c vendor/tre-regex/tre-mem.c)
+endif()
+
 set(CST_SOURCES ${CST_CORE_SOURCES} src/main.c)
 
 if(CST_BUILD_TUI)
@@ -92,6 +130,7 @@ endif()
 
 add_executable(cst-agent ${CST_SOURCES})
 add_dependencies(cst-agent sashidown)
+cst_win_exe(cst-agent)
 
 target_include_directories(cst-agent PRIVATE
   include
@@ -113,9 +152,26 @@ if(NOT WIN32)
   target_link_libraries(cst-agent PRIVATE m)
 endif()
 
-if(CST_BUILD_TUI)
+set(CST_WIN_CURSES "ncurses" CACHE STRING "Windows TUI backend: ncurses or pdcurses")
+set_property(CACHE CST_WIN_CURSES PROPERTY STRINGS ncurses pdcurses)
+if(CST_BUILD_TUI AND WIN32 AND CST_WIN_CURSES STREQUAL "ncurses")
+  # ncursesw built by scripts/build_third_party_mingw.sh ncurses (or MSYS2's
+  # mingw-w64-ucrt-x86_64-ncurses); headers live in include/ncursesw.
+  find_path(NCURSESW_INCLUDE_DIR ncurses.h PATH_SUFFIXES ncursesw include/ncursesw)
+  find_library(NCURSESW_LIBRARY NAMES ncursesw)
+  if(NOT NCURSESW_INCLUDE_DIR OR NOT NCURSESW_LIBRARY)
+    message(FATAL_ERROR "CST_WIN_CURSES=ncurses needs ncursesw "
+      "(scripts/build_third_party_mingw.sh ncurses), or -DCST_WIN_CURSES=pdcurses")
+  endif()
+  # ncurses.h includes <ncursesw/ncurses_dll.h>, so the parent is needed too
+  get_filename_component(NCURSESW_PARENT_DIR ${NCURSESW_INCLUDE_DIR} DIRECTORY)
+  target_include_directories(cst-agent PRIVATE ${NCURSESW_INCLUDE_DIR} ${NCURSESW_PARENT_DIR})
+  target_link_libraries(cst-agent PRIVATE ${NCURSESW_LIBRARY})
+  target_compile_definitions(cst-agent PRIVATE CST_USE_NCURSES=1 NCURSES_STATIC=1 NCURSES_WIDECHAR=1)
+  message(STATUS "TUI: ncursesw (${NCURSESW_LIBRARY})")
+elseif(CST_BUILD_TUI)
   if(WIN32)
-    # Prefer PDCurses (pdcurses / curses). Users may set PDCurses_ROOT.
+    # PDCurses (pdcurses / curses). Users may set PDCurses_ROOT.
     # PATH_SUFFIXES also covers the layout MSYS2's mingw-w64-pdcurses uses,
     # which puts the headers under include/pdcurses/ rather than include/.
     find_path(PDCURSES_INCLUDE_DIR curses.h
@@ -156,7 +212,7 @@ endif()
 if(CMAKE_SYSTEM_NAME STREQUAL "Windows" OR WIN32)
   # curl Schannel + networking; winmm is needed by PDCurses (PlaySoundW)
   target_link_libraries(cst-agent PRIVATE
-    ws2_32 crypt32 secur32 bcrypt advapi32 winmm)
+    ws2_32 crypt32 secur32 bcrypt advapi32 user32 gdi32 winmm)
 endif()
 
 # --- tests ---
@@ -166,7 +222,11 @@ set(_CST_SMALL_TESTS test_ctl_frontier test_ctl_heredoc test_json_baseline
     test_markdown)
 foreach(t ${_CST_SMALL_TESTS})
   if(t STREQUAL test_textsel)
-    add_executable(${t} tests/${t}.c src/textsel.c)
+    add_executable(${t} tests/${t}.c src/textsel.c src/os_compat.c src/os_win.c
+      src/util.c)
+    if(WIN32)
+      target_link_libraries(${t} PRIVATE advapi32 user32)
+    endif()
   elseif(t STREQUAL test_markdown)
     add_executable(${t} tests/${t}.c)
     target_include_directories(${t} PRIVATE "${SD_DIR}/include")
@@ -186,6 +246,7 @@ foreach(t ${_CST_SMALL_TESTS})
   if(NOT WIN32)
     target_link_libraries(${t} PRIVATE m)
   endif()
+  cst_win_exe(${t})
   add_test(NAME ${t} COMMAND ${t} WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}")
 endforeach()
 
@@ -194,7 +255,8 @@ foreach(t test_llm_body test_sse_decode test_apply_patch test_session_roundtrip
           test_shell test_diff test_tools_fs test_registry
           test_undo test_config test_models test_sandbox
           test_keymap test_shell_compact test_skills
-          test_plugins test_mcp test_subagent)
+          test_plugins test_mcp test_subagent test_lowil
+          test_win_utf8 test_os_dir)
   add_executable(${t} tests/${t}.c ${CST_CORE_SOURCES})
   target_include_directories(${t} PRIVATE include "${CJSON_DIR}")
   target_compile_definitions(${t} PRIVATE _GNU_SOURCE)
@@ -202,8 +264,9 @@ foreach(t test_llm_body test_sse_decode test_apply_patch test_session_roundtrip
   if(NOT WIN32)
     target_link_libraries(${t} PRIVATE m)
   else()
-    target_link_libraries(${t} PRIVATE ws2_32 crypt32 secur32 bcrypt advapi32)
+    target_link_libraries(${t} PRIVATE ws2_32 crypt32 secur32 bcrypt advapi32 user32)
   endif()
+  cst_win_exe(${t})
   add_test(NAME ${t} COMMAND ${t} WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}")
 endforeach()
 
diff --git a/Makefile b/Makefile
index c9a2cdb..43bd510 100644
--- a/Makefile
+++ b/Makefile
@@ -55,6 +55,7 @@ CORE_SRC = \
 	src/util.c \
 	src/ctl_parse.c \
 	src/os_compat.c \
+	src/os_win.c \
 	src/sandbox.c \
 	src/sandbox_exec.c \
 	src/keymap.c \
@@ -110,7 +111,10 @@ TESTS = \
 	tests/test_skills \
 	tests/test_plugins \
 	tests/test_mcp \
-	tests/test_subagent
+	tests/test_subagent \
+	tests/test_lowil \
+	tests/test_win_utf8 \
+	tests/test_os_dir
 
 TEST_LIBS = -lm $(CURL_LIBS) $(PTHREAD_LIBS)
 
@@ -163,8 +167,8 @@ tests/test_replay_real: tests/test_replay_real.c src/ctl_parse.c src/json_baseli
 tests/test_mm_tool: tests/test_mm_tool.c src/mm_tool.c include/mm_tool.h
 	$(CC) $(CFLAGS) $(CPPFLAGS) -o $@ tests/test_mm_tool.c src/mm_tool.c
 
-tests/test_textsel: tests/test_textsel.c src/textsel.c include/cst_textsel.h
-	$(CC) $(CFLAGS) $(CPPFLAGS) -o $@ tests/test_textsel.c src/textsel.c
+tests/test_textsel: tests/test_textsel.c src/textsel.c src/os_compat.c src/os_win.c src/util.c include/cst_textsel.h
+	$(CC) $(CFLAGS) $(CPPFLAGS) -o $@ tests/test_textsel.c src/textsel.c src/os_compat.c src/os_win.c src/util.c
 
 tests/test_markdown: tests/test_markdown.c $(SD_DIR)/libsashidown.a
 	$(CC) $(CFLAGS) $(CPPFLAGS) -o $@ tests/test_markdown.c $(LDFLAGS) -lsashidown -lm
diff --git a/README.md b/README.md
index ea7c125..b766e4a 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,15 @@ cst-agent --version
 cd ~/my-project && cst-agent
 ```
 
+Windows 10 1903+（PowerShell，不需要管理员）：
+
+```powershell
+irm https://git.whcself.xyz/WHC/CST-agent/raw/branch/main/scripts/install_windows.ps1 | iex
+# 新开终端后：cd 到项目目录运行 cst-agent；升级用 cst-agent-update
+```
+
+详见 [docs/README-windows.md](docs/README-windows.md)。
+
 一键脚本可以重复运行：已有仓库会 `git pull --ff-only`，代码有更新时干净重编，然后重新安装；
 同时装一个 `cst-agent-update` 命令（等同重跑脚本）。NixOS 上会自动进 `nix-shell` 编译。
 
@@ -39,8 +48,9 @@ cd ~/my-project && cst-agent
 |---|---|
 | Linux | [`scripts/bootstrap_linux.sh`](scripts/bootstrap_linux.sh) |
 | Termux | [`scripts/bootstrap_termux.sh`](scripts/bootstrap_termux.sh) |
+| Windows 安装 / 升级 | [`scripts/install_windows.ps1`](scripts/install_windows.ps1)（从 Release 安装），之后 `cst-agent-update` |
 | Windows 交叉构建（在 Linux 上） | [`scripts/bootstrap_windows.sh`](scripts/bootstrap_windows.sh) → `dist/windows-x86_64/` |
-| Windows 运行 | 拷贝 dist 后 [`scripts/run_windows.bat`](scripts/run_windows.bat) |
+| Windows 原生构建（MSYS2 UCRT64） | [`scripts/bootstrap_msys2.sh`](scripts/bootstrap_msys2.sh) → `dist/windows-x86_64/` |
 
 ### 迷你验收工程（论文案例）
 
@@ -97,14 +107,11 @@ cmake --build build-clang
 # Headless only（无 ncurses）
 cmake -B build-hd -DCST_BUILD_TUI=OFF && cmake --build build-hd
 
-# Windows MinGW 交叉（需安装 mingw-w64）
-cmake -B build-win -DCMAKE_TOOLCHAIN_FILE=cmake/mingw-w64-x86_64.cmake \
-  -DCST_BUILD_TUI=OFF
-cmake --build build-win
-# TUI：安装 PDCurses 后 -DCST_BUILD_TUI=ON -DPDCurses_ROOT=...
+# Windows：用一键脚本（见下方“Windows 发行包”），会先编译静态依赖
+./scripts/bootstrap_windows.sh
 ```
 
-依赖：`gcc` 或 `clang`、`libcurl`、Linux TUI 需 `ncursesw`；Windows TUI 需 **PDCurses**。
+依赖：`gcc` 或 `clang`、`libcurl`、TUI 需 `ncursesw`（Windows 版用打过补丁的 ncurses 6.6，脚本自动编译）。
 Sashidown（`vendor/sashidown`）与 cJSON（`vendor/cjson`，MIT）已随仓库提供。  
 API Key：TUI 里输入并按 provider 保存到配置目录的 `credentials`（权限 0600）；`/key` 更换，`--ask-key` 在命令行输入。
 `--api-key` 只用于本次进程、不落盘；`DEEPSEEK_API_KEY` 等环境变量和 `CST_API_KEY` 仅作为没有保存 key 时的兜底（方便 CI）。
@@ -117,7 +124,7 @@ API Key：TUI 里输入并按 provider 保存到配置目录的 `credentials`（
 | WSL2 | x86_64 | 同 Linux | yes | ncursesw | `/bin/sh`（工作区建议放在 Linux 文件系统内） |
 | macOS | arm64 / x86_64 | Apple Clang | yes | ncurses（Homebrew） | `/bin/sh` |
 | Android Termux | aarch64 / … | Clang (Termux) | yes | ncurses（Termux 包） | `$PREFIX/bin/sh`；可旁路 busybox |
-| Windows | x86_64 / aarch64 | MinGW GCC/Clang | yes | PDCurses | **捆绑 busybox-w32** |
+| Windows 10 1903+ | x86_64 | MinGW-w64 GCC（UCRT） | yes | ncurses 6.6（Windows 控制台） | **捆绑 busybox-w32** |
 
 ### Termux
 
@@ -140,17 +147,14 @@ make && make install      # 装到 Termux 的 $PREFIX/bin，之后任意目录
 
 ### Windows 发行包
 
-见 [docs/README-windows.md](docs/README-windows.md)。交叉构建：
+见 [docs/README-windows.md](docs/README-windows.md)（安装、编码、沙箱、构建、已知限制）。
 
 ```bash
-./scripts/build_third_party_mingw.sh all   # curl+PDCurses+busybox-w32
-# 源码：https://github.com/rmyorston/busybox-w32.git
-#       https://github.com/mirror/busybox.git （Unix）
-cmake -B build-win-tui -DCMAKE_TOOLCHAIN_FILE=cmake/mingw-w64-x86_64.cmake \
-  -DCST_BUILD_TUI=ON -DCMAKE_PREFIX_PATH=$PWD/third_party/prefix-mingw
+./scripts/bootstrap_windows.sh   # Linux 交叉编译；Windows 上在 MSYS2 UCRT64 里用 scripts/bootstrap_msys2.sh
 ```
 
-产物示例：`dist/windows-x86_64/`（含 `cst-agent.exe` + `busybox.exe` + `libwinpthread-1.dll`）。
+产物：`dist/windows-x86_64/`（静态链接的 `cst-agent.exe` + `busybox.exe`，无其他 DLL）和
+`dist/cst-agent-VERSION-windows-x86_64.zip`；`GITEA_TOKEN=... scripts/release_windows.sh` 上传到 Release。
 
 环境变量：`CST_SHELL`、`CST_EXE_DIR`、`CST_AUTO_APPROVE` 等。
 
@@ -275,8 +279,11 @@ TUI 中 `/tools off NAME`、`/tools on NAME` 可临时开关单个工具。
     读、执行和已打开文件的写入不检查。它防的是误操作而不是恶意程序：检查之后内核会再读一次路径，多线程程序可以趁机换掉。
     比 shell 活得久的后台进程：桌面发行版开着 Yama（`ptrace_scope` ≥ 1）时它们的受检写入会被拒；命令结束后一律失败。
   - macOS：`sandbox_init` profile，同样只放行工作区和临时目录写入，禁网。
-  - Windows、更老的内核：没有沙箱，自动回落到规则判断（界面显示 `auto · rules`）。
-  - `CST_SANDBOX=off` 强制关闭沙箱；`CST_SANDBOX=landlock` / `seccomp` 只用指定的那种。
+  - Windows 10 1903+：Low 完整性级别的受限令牌 + Job Object（界面显示 `auto · lowil`）。第一次在工作区运行时
+    给它打上 Low 标签，之后子进程只能写工作区和沙箱临时目录，读不到凭据文件；不限制联网，所以联网命令仍会询问。
+    `/sandbox` 查看、`/sandbox reset-labels` 撤销标签，详见 [docs/README-windows.md](docs/README-windows.md)。
+  - 更老的内核：没有沙箱，自动回落到规则判断（界面显示 `auto · rules`）。
+  - `CST_SANDBOX=off` 强制关闭沙箱；`CST_SANDBOX=landlock` / `seccomp` / `lowil` 只用指定的那种。
   - 沙箱里的命令如果像是被拦了（`Permission denied` / `权限不够` / `Read-only file system` 等），会弹窗问
     “Rerun outside the sandbox?”：`y` 在沙箱外重跑一次 · `p` 保存命令前缀规则并重跑 · `n` 保留沙箱结果（模型会收到说明）。
 - **只读白名单**（无沙箱时 `auto` 用）：`ls cat head tail wc grep rg find pwd echo which file stat du tree`
diff --git a/docs/README-windows.md b/docs/README-windows.md
index b2099d4..7e8ebc4 100644
--- a/docs/README-windows.md
+++ b/docs/README-windows.md
@@ -1,82 +1,177 @@
 # CST-Agent on Windows
 
-## Release layout
+原生 Windows 版：一个静态链接的 `cst-agent.exe`（UCRT，内嵌 UTF-8 清单）加一个
+`busybox.exe`（busybox-w32 Unicode 版）作为 shell，不依赖其他 DLL，也不需要管理员权限。
 
-```
-cst-agent.exe
-busybox.exe              # built from busybox-w32
-libwinpthread-1.dll      # MinGW runtime (required)
-LICENSE.busybox
-README-windows.md
+## 安装
+
+在 PowerShell 里（Windows PowerShell 5.1 或 PowerShell 7 都行）：
+
+```powershell
+irm https://git.whcself.xyz/WHC/CST-agent/raw/branch/main/scripts/install_windows.ps1 | iex
 ```
 
-Prebuilt tree from Linux cross-compile: `agent/dist/windows-x86_64/`.
-
-## Build (MinGW-w64 cross from Linux)
-
-```bash
-cd agent
-# 1) third-party: curl (Schannel) + PDCurses + busybox-w32
-./scripts/build_third_party_mingw.sh all
-# sources:
-#   https://github.com/rmyorston/busybox-w32.git
-#   https://github.com/curl/curl.git
-#   https://github.com/wmcbrine/PDCurses.git
-# Unix busybox (optional, Linux/Termux bundle):
-#   ./scripts/build_third_party_mingw.sh busybox-unix
-#   https://github.com/mirror/busybox.git
-
-# 2) headless
-cmake -B build-win -DCMAKE_TOOLCHAIN_FILE=cmake/mingw-w64-x86_64.cmake \
-  -DCST_BUILD_TUI=OFF -DCMAKE_PREFIX_PATH=$PWD/third_party/prefix-mingw
-cmake --build build-win
-
-# 3) TUI (PDCurses)
-cmake -B build-win-tui -DCMAKE_TOOLCHAIN_FILE=cmake/mingw-w64-x86_64.cmake \
-  -DCST_BUILD_TUI=ON -DCMAKE_PREFIX_PATH=$PWD/third_party/prefix-mingw \
-  -DPDCurses_ROOT=$PWD/third_party/prefix-mingw
-cmake --build build-win-tui
-```
-
-Copy `build-win-tui/cst-agent.exe`, `third_party/busybox/busybox.exe`, and
-`libwinpthread-1.dll` into one folder.
-
-## Build natively on Windows (MSYS2)
-
-The CMake build also works directly on Windows with MSYS2's mingw-w64
-toolchain -- no separate Linux host needed:
-
-```bash
-# in an MSYS2 MINGW64 shell
-pacman -S --needed --noconfirm \
-  mingw-w64-x86_64-gcc mingw-w64-x86_64-cmake mingw-w64-x86_64-make \
-  mingw-w64-x86_64-curl mingw-w64-x86_64-pdcurses
-
-cd agent
-cmake -B build-win -G "MinGW Makefiles" -DCMAKE_BUILD_TYPE=Release
-cmake --build build-win --target cst-agent -j"$(nproc)"
-```
-
-`CST_BUILD_TUI=ON` (the default) picks up MSYS2's PDCurses automatically,
-including its `include/pdcurses/` layout; set `-DPDCurses_ROOT=...` only for
-a custom PDCurses.
-
-Two differences from the cross-build release layout above:
-
-- **Extra DLLs.** MSYS2's curl package is the shared OpenSSL build, so the
-  executable needs its whole dependency chain beside it. Collect it with
-  `ldd build-win/cst-agent.exe | grep mingw64`.
-- **Only build the `cst-agent` target.** Some sources under `tests/` are
-  POSIX-only (two-argument `mkdir`, `setenv`, `arpa/inet.h`, `symlink`) and
-  do not compile with MinGW. The main program is unaffected.
-
-## Run
+脚本从 Gitea Release 下载 `cst-agent-VERSION-windows-x86_64.zip`，校验 `.sha256`，
+装到 `%LOCALAPPDATA%\Programs\cst-agent`，并把这个目录加进**用户** PATH。装完新开一个终端：
 
 ```bat
-set CST_API_KEY=...
-cst-agent.exe --headless --workspace . --prompt "echo hi"
-cst-agent.exe --workspace .
+cd C:\code\my-project
+cst-agent
 ```
 
-Shell: bundled `busybox.exe sh -c ...` unless `CST_SHELL` is set.
-Credentials: `%APPDATA%\cst-agent\credentials` (or console prompt).
+首次启动会让你选 provider 并输入 API key（遮罩输入，按 provider 保存）。
+
+以后升级：
+
+```bat
+cst-agent-update                 :: 最新版
+cst-agent-update -Version 0.6.0  :: 指定版本
+```
+
+正在运行的 `cst-agent.exe` 不会挡住升级：旧文件会先改名为 `.old`，下次升级时删掉。
+
+安装脚本的参数（下载后用 `powershell -ExecutionPolicy Bypass -File install_windows.ps1 ...` 运行）：
+
+| 参数 | 环境变量 | 作用 |
+|---|---|---|
+| `-Version 0.6.0` | `CST_VERSION` | 指定版本，默认最新 |
+| `-Prefix D:\tools\cst` | `CST_PREFIX` | 安装目录 |
+| `-Zip FILE` | | 用本地 zip，不联网 |
+| `-NoPath` | | 不改用户 PATH |
+| | `CST_GITEA` / `CST_REPO` | 换 Gitea 服务器或仓库（默认 `WHC/CST-agent`） |
+
+不想用脚本的话，把 zip 解压到任意目录直接运行 `cst-agent.exe` 也可以。
+
+## 系统要求
+
+- Windows 10 1903（build 18362）及以上、Windows 11、Windows Server 2022 / 2025。
+  更老的系统不认清单里的 `activeCodePage=UTF-8`，安装脚本会直接拒绝。
+- x86_64。Windows 10 1903 起系统自带 UCRT，无需另装运行库。
+- 终端：Windows Terminal 或传统控制台（conhost）都行。
+
+## 发行包内容
+
+```
+windows-x86_64/
+  cst-agent.exe          # 静态链接：curl（Schannel）、ncurses 6.6、winpthreads
+  busybox.exe            # busybox-w32 Unicode 版，run_shell 用它的 sh
+  LICENSE.busybox
+  README.md              # 本文件
+  VERSION
+  cst-agent-update.cmd   # 调用旁边的 install_windows.ps1 升级本目录
+  install_windows.ps1
+```
+
+## 文件位置
+
+| 内容 | 位置 |
+|---|---|
+| API key（每个 provider 一个） | `%APPDATA%\cst-agent\credentials`，只有当前用户可读，并带“禁止向上读”标签（沙箱内读不到） |
+| 上次的 provider、模型、推理强度、确认模式 | `%APPDATA%\cst-agent\settings.json` |
+| 沙箱打过标签的目录 | `%APPDATA%\cst-agent\sandbox-labels` |
+| 会话、撤销快照、导出 | `<工作区>\.agent\` |
+
+设置了绝对路径的 `XDG_CONFIG_HOME` 时用 `%XDG_CONFIG_HOME%\cst-agent`。
+
+## 编码：全部 UTF-8
+
+- exe 内嵌 `activeCodePage=UTF-8` 清单：进程的 ANSI 代码页就是 65001，命令行参数、
+  环境变量、文件名都以 UTF-8 进出；内部所有路径在系统调用边界转成 UTF-16（`*W` API）。
+- 控制台输入输出代码页在启动时设为 65001，退出时恢复。
+- 文件按字节读写，不做换行转换。`read_file` 给模型看的是去掉 `\r` 的文本；`edit_file`、
+  `apply_patch`、`write_file` 会保持原文件的 CRLF 换行和 UTF-8 BOM。
+- 子进程输出：先按 UTF-8 解码；不是合法 UTF-8 时依次尝试控制台代码页、系统 OEM / ANSI
+  代码页（比如中文系统的 936），转成 UTF-8 再交给模型。
+- 中文用户名、中文工作区路径（`C:\Users\测试\项目`）都已在中英文系统上测过。
+
+## 终端界面（TUI）
+
+用的是打过补丁的 ncurses 6.6 Windows 控制台驱动（补丁在
+`scripts/patches/ncurses-6.6-win32-console.patch`）：
+
+- 中文按两列宽显示，光标位置正确；粘贴多行不会直接发送。
+- 鼠标：点击、拖选复制（写入 Windows 剪贴板）、滚轮滚动；`/mouse` 关闭。
+- `/copy` 和拖选复制走 Win32 剪贴板 API，不依赖终端的 OSC 52。
+- 控制台是点阵字体时（显示不了中文，会变成 `?`），启动时自动换成同字号的 Consolas
+  （中文系统换成新宋体），退出时换回去。
+- 传统控制台不做字形回退：当前字体缺 logo 用的方块字符时（比如中文系统默认的新宋体），
+  首页改用文字 logo。
+
+## Shell 沙箱：Low 完整性级别
+
+`auto` 确认模式下，`run_shell` 在 Low 完整性级别的受限令牌里运行（界面显示 `auto · lowil`）：
+
+- 子进程的令牌去掉了管理员组和特权，完整性级别为 Low（S-1-16-4096），放进 Job Object，
+  超时或按 Esc 时整个进程树一起结束。
+- Low 进程只能写标为 Low 的位置。第一次在某个工作区跑沙箱命令时，CST-Agent 给工作区
+  加上可继承的 Low 标签（`S:(ML;OICI;NW;;;LW)`），并在输出里提示一次；
+  记录写进 `sandbox-labels`。沙箱的临时目录是 `%TEMP%\cst-agent-sandbox`（同样标为 Low），
+  子进程的 `TEMP` / `TMP` 指向这里。
+- 不会给盘符根目录、用户目录本身、`%APPDATA%`、`%LOCALAPPDATA%`、`%TEMP%` 本身，
+  以及 Windows、Program Files、ProgramData 下面的目录打标签：在这些地方启动时，命令不会运行，
+  界面会问是否在沙箱外重跑。请在项目目录里启动。
+- `/sandbox` 列出打过标签的目录；`/sandbox reset-labels` 恢复它们原来的标签。
+- 沙箱里可以读、执行用户能访问的文件（凭据文件除外），**不限制联网**。所以像联网的命令
+  （`curl`、`wget`、`ssh`、`git clone/fetch/pull/push`、`npm install`、`pip install`、
+  `winget install`、`Invoke-WebRequest` 等）在 `auto` 模式下仍然会弹窗确认。
+- 命令像是被拦了（`Access is denied`、`拒绝访问`、`Permission denied` 等）时，会问
+  “Rerun outside the sandbox?”：`y` 在沙箱外重跑一次，`p` 保存命令前缀规则并重跑，`n` 保留结果。
+- MSYS2 / Cygwin 的程序（包括 Git for Windows 自带的 `usr\bin` 工具）在 Low 级别下无法初始化
+  （`0xc0000142`），同样会触发上面的重跑询问。Git for Windows 的 `git.exe` 本身不受影响。
+- `CST_SANDBOX=off` 关闭沙箱（`auto` 退回只读白名单规则）；`CST_SANDBOX=lowil` 只用 Low IL。
+
+它防的是误操作写坏工作区以外的文件，不是对抗恶意程序的安全边界。
+
+## 从源码构建
+
+两种方式产物一样：`dist/windows-x86_64/` 和 `dist/cst-agent-VERSION-windows-x86_64.zip`。
+第三方依赖（curl、ncurses、busybox-w32）都按固定版本从源码编译、静态链接。
+
+### 在 Linux 上交叉编译
+
+```bash
+git clone https://git.whcself.xyz/WHC/CST-agent.git
+cd CST-agent
+scripts/bootstrap_windows.sh
+```
+
+NixOS / 有 Nix 时自动进 `shell-win.nix`（`pkgsCross.ucrt64`）；否则需要 UCRT 版的
+`x86_64-w64-mingw32-gcc`（带 winpthreads）、cmake、ninja、git、perl。
+
+### 在 Windows 上用 MSYS2 原生编译
+
+装好 [MSYS2](https://www.msys2.org/) 后，打开 **MSYS2 UCRT64** 终端（不是 MINGW64：
+MINGW64 链接 msvcrt，UTF-8 清单不起作用）：
+
+```bash
+pacman -S --needed git
+git clone https://git.whcself.xyz/WHC/CST-agent.git
+cd CST-agent
+scripts/bootstrap_msys2.sh
+```
+
+脚本会用 pacman 装 UCRT64 的 gcc / cmake / ninja，编译依赖和 `cst-agent.exe`，跑 ctest
+（`CST_SKIP_TESTS=1` 跳过），再打包。
+
+### 测试
+
+`scripts/win_test.sh` 在本机 QEMU 里的 Windows Server 虚拟机（英文 / 中文系统，管理员 /
+普通用户 / 中文用户名）上交叉编译后跑全部测试；虚拟机的创建和控制见 `scripts/winvm/`。
+
+### 发布
+
+```bash
+GITEA_TOKEN=... scripts/release_windows.sh --build
+```
+
+创建（或复用）`vVERSION` Release，上传 zip 和 `.sha256`。token 只从环境变量读取，经 stdin
+交给 curl，不会出现在命令行参数、磁盘或输出里。
+
+## 已知限制
+
+- 英文等非中文系统的传统控制台默认用 Consolas，它没有中文字形，中文会显示成方框（列宽仍然正确）。
+  用 Windows Terminal，或在控制台“属性 → 字体”里选新宋体等中文字体即可。
+- 传统控制台里输入表情符号（BMP 以外的字符）可能显示不对；中文输入没问题。
+- 通过 SSH / ConPTY 远程运行时，鼠标事件不会转发过来，键盘操作不受影响。
+- 很大的工作区第一次打标签要等一会儿（标签要继承到每个文件）。
+- 只有 x86_64 发行包。
diff --git a/docs/compat.md b/docs/compat.md
index 57baf24..052cf4a 100644
--- a/docs/compat.md
+++ b/docs/compat.md
@@ -48,12 +48,13 @@ write beneath the workspace, the temp directory, `/dev/null` and `/dev/tty`.
 | Linux 5.13+ | Landlock (raw syscalls, no extra library) | ABI ≥ 4 (6.7+) also blocks TCP connect/bind |
 | Linux 5.5+ without Landlock (Android / Termux, WSL, older distros), x86_64 / aarch64 | seccomp user-notify | refuses IPv4/IPv6 sockets; see below |
 | macOS | `sandbox_init` profile | also denies network |
-| Older kernels, Windows | none | falls back to the read-only rules |
+| Windows 10 1903+ | Low integrity restricted token + Job Object | writes need a Low label (given to the workspace once); network is not blocked, so network commands still ask; see `README-windows.md` |
+| Older kernels | none | falls back to the read-only rules |
 
 The status bar and sidebar show `auto · landlock`, `auto · seccomp`,
-`auto · seatbelt` or `auto · rules`. `CST_SANDBOX=off` disables the
-sandbox; `CST_SANDBOX=landlock` or `CST_SANDBOX=seccomp` allows only that
-kind. When a sandboxed command looks blocked, the TUI asks whether to rerun
+`auto · seatbelt`, `auto · lowil` or `auto · rules`. `CST_SANDBOX=off`
+disables the sandbox; `CST_SANDBOX=landlock`, `seccomp` or `lowil` allows
+only that kind. When a sandboxed command looks blocked, the TUI asks whether to rerun
 it outside the sandbox. The policy is built in the parent; the forked child
 only makes a few async-signal-safe syscalls before `exec`, so the agent
 itself is never confined.
@@ -140,7 +141,7 @@ TUI:
 - [ ] Tab toggles Build/Plan, Shift+Tab cycles ask/auto/yolo, Ctrl+P opens the palette
 - [ ] `/model` lists the provider's `/models` (marked `(api)`); a wrong key is re-asked
 - [ ] `auto` mode: `echo x > ~/outside` in run_shell asks "Rerun outside the
-      sandbox?" (Linux/Termux/macOS); with `CST_SANDBOX=off`, `ls` runs and `touch x` asks
+      sandbox?" (Linux/Termux/macOS/Windows); with `CST_SANDBOX=off`, `ls` runs and `touch x` asks
 - [ ] Resize the terminal during streaming: layout recovers
 - [ ] `NO_COLOR=1` and `CST_ASCII=1` render readable screens
 
@@ -149,6 +150,23 @@ WSL specifics:
 - [ ] Workspace under `/mnt/c/...` works (slower IO is expected); `~/project` is recommended
 - [ ] Windows Terminal: mouse wheel scroll and OSC 52 `/copy`
 
+Windows specifics (`scripts/win_test.sh` runs the tests on English and
+Chinese VMs as Administrator, a standard user and a Chinese user name):
+
+- [ ] `install_windows.ps1 -Zip dist\cst-agent-*.zip` installs, adds the user
+      PATH; `cst-agent-update -Zip ...` works while `cst-agent.exe` runs
+- [ ] conhost with a raster font: Chinese renders (font switched), and the
+      old font is back after exit; Windows Terminal renders the same
+- [ ] Chinese input via IME, paste, mouse click / drag-copy / wheel
+- [ ] Workspace under `C:\Users\<中文名>\项目`: read/write/edit/apply_patch
+      keep CRLF and BOM; `run_shell` output in Chinese is readable on a
+      936 system
+- [ ] `auto · lowil`: first command reports the label; `echo x > C:\outside`
+      asks to rerun; `curl ...` asks before running; `/sandbox reset-labels`
+      restores the label
+- [ ] Esc during `sleep 30 & sleep 30` returns at once and leaves no
+      `busybox.exe` behind
+
 macOS specifics:
 
 - [ ] Builds with Homebrew ncurses and with the system ncurses (`brew unlink ncurses`)
diff --git a/docs/windows_selftest.md b/docs/windows_selftest.md
index d84a998..abaf997 100644
--- a/docs/windows_selftest.md
+++ b/docs/windows_selftest.md
@@ -1,11 +1,9 @@
 # Windows self-test checklist
 
-Run on a Windows machine (or wine) after MinGW build + busybox.exe beside the binary.
+Automated: `scripts/win_test.sh` cross-builds and runs every test on the
+English and Chinese Windows Server VMs as Administrator, a standard user and
+a Chinese user name (VM tooling in `scripts/winvm/`).
 
-1. `cst-agent.exe --help` exits 0
-2. `set CST_API_KEY=...` then `--headless --workspace . --prompt "run echo hello"` — tool output contains hello
-3. `write_file` under workspace succeeds; path outside workspace rejected
-4. Credentials saved under `%APPDATA%\cst-agent\credentials`
-5. With PDCurses build: launch without `--headless`, confirm TUI draws, `/help` works, Esc cancels
-
-Shell must resolve to bundled busybox unless `CST_SHELL` is set.
+Manual: the "Windows specifics" list in [compat.md](compat.md), plus the
+general CLI and TUI items there. Install and sandbox details are in
+[README-windows.md](README-windows.md).
diff --git a/include/cst_perms.h b/include/cst_perms.h
index 09c2c3e..8f86fea 100644
--- a/include/cst_perms.h
+++ b/include/cst_perms.h
@@ -26,6 +26,9 @@ void cst_perms_suggest_prefix(const char *cmd, char *out, size_t out_sz);
 /* 1 when every segment of cmd (split on | || && ;) is a read-only command
  * from a fixed whitelist, with no output redirection or substitution. */
 int cst_shell_is_safe(const char *cmd);
+/* 1 when cmd looks like it talks to the network (curl, ssh, git push,
+ * npm install, ...). Errs on the side of yes. */
+int cst_shell_uses_network(const char *cmd);
 
 #ifdef __cplusplus
 }
diff --git a/include/cst_sandbox.h b/include/cst_sandbox.h
index 555d63f..c104b05 100644
--- a/include/cst_sandbox.h
+++ b/include/cst_sandbox.h
@@ -12,6 +12,10 @@
  *           against mistakes, not hostile code (the path is checked before
  *           the kernel reads it again).
  *   macOS   sandbox_init (Seatbelt profile)
+ *   Windows Low integrity level: a restricted token (no admin privileges,
+ *           Low IL) can only write objects labeled Low, so the workspace and
+ *           a temp dir get that label; the credentials file is labeled
+ *           no-read-up. The network stays open (callers ask first).
  *   other   none: callers fall back to rule-based approval
  */
 
@@ -27,15 +31,16 @@ typedef enum {
   CST_SANDBOX_NONE = 0,
   CST_SANDBOX_LANDLOCK,
   CST_SANDBOX_SEATBELT,
-  CST_SANDBOX_SECCOMP
+  CST_SANDBOX_SECCOMP,
+  CST_SANDBOX_LOWIL
 } cst_sandbox_kind_t;
 
 /* What this process can use; cached. CST_SANDBOX=off|0|none forces NONE,
- * CST_SANDBOX=landlock|seccomp allows only that kind. */
+ * CST_SANDBOX=landlock|seccomp|lowil allows only that kind. */
 int cst_sandbox_probe(void);
 /* Drops the cache and probes again (tests that change CST_SANDBOX). */
 int cst_sandbox_reprobe(void);
-/* "landlock" | "seatbelt" | "seccomp" | "none" */
+/* "landlock" | "seatbelt" | "seccomp" | "lowil" | "none" */
 const char *cst_sandbox_name(int kind);
 /* Landlock ABI version (0 when unavailable); ≥4 also blocks TCP. */
 int cst_sandbox_landlock_abi(void);
@@ -45,6 +50,9 @@ typedef struct {
   int ruleset_fd; /* Landlock, built in the parent */
   char *profile;  /* Seatbelt */
   void *sc;       /* seccomp: filter program and supervisor thread */
+  void *token;    /* lowil: primary token for CreateProcessAsUserW */
+  char *tmpdir;   /* lowil: Low-labeled TEMP for the child */
+  char *note;     /* lowil: shown once when a directory was just labeled */
 } cst_sandbox_plan_t;
 
 /* Parent side: build the policy. Returns 0, or -1 (plan->kind = NONE). */
@@ -64,6 +72,14 @@ int cst_sandbox_run_shell(const char *workspace, const char *cmd,
  * way (EACCES / EPERM / EROFS / blocked network). */
 int cst_sandbox_blocked(const char *out, size_t n, int exit_code);
 
+/* lowil: directories this user's cst-agent labeled Low (recorded in the
+ * config dir), one per line; malloc'd, NULL when there are none. */
+char *cst_sandbox_labels(void);
+/* Gives every recorded directory its old label back. Returns how many were
+ * restored (-1 when some failed; those stay recorded); *report gets a
+ * malloc'd summary. */
+int cst_sandbox_reset_labels(char **report);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/include/cst_util.h b/include/cst_util.h
index 751ed39..abf922e 100644
--- a/include/cst_util.h
+++ b/include/cst_util.h
@@ -25,6 +25,27 @@ char *cst_buf_steal(cst_buf_t *b);
 size_t cst_utf8_floor(const char *s, size_t n);
 /* Copy s[0..n) replacing invalid UTF-8 with '?'. malloc'd, NUL-terminated. */
 char *cst_utf8_sanitize(const char *s, size_t n, size_t *out_len);
+int cst_utf8_valid(const char *s, size_t n);
+
+/* Text files may start with a UTF-8 BOM (Windows editors): its length (0/3),
+ * and an in-place strip of the NUL-terminated s (*len updated when given). */
+size_t cst_bom_len(const char *s, size_t n);
+void cst_strip_bom(char *s, size_t *len);
+/* Line endings: "\r\n" -> "\n" in place (returns the new length); whether
+ * every line of s ends in "\r\n" (and at least one does); and a malloc'd
+ * copy of s with bare "\n" turned into "\r\n" when crlf, its BOM dropped and
+ * a BOM added when bom. Edits keep a Windows file's style with these. */
+size_t cst_crlf_to_lf(char *s, size_t n);
+int cst_text_is_crlf(const char *s, size_t n);
+char *cst_text_restyle(const char *s, size_t n, int crlf, int bom,
+                       size_t *out_len);
+
+/* fnmatch(3) without FNM_PATHNAME ('*' also crosses '/'): * ? [..] [!..]
+ * [[:class:]] and backslash escapes over UTF-8 code points. Returns 0 on a
+ * match. Always case-insensitive on Windows. */
+#define CST_FNM_PERIOD 1   /* a leading '.' must be matched literally */
+#define CST_FNM_CASEFOLD 2
+int cst_fnmatch(const char *pat, const char *str, int flags);
 
 uint64_t cst_fnv1a64(uint64_t h, const void *data, size_t n);
 #define CST_FNV_INIT 1469598103934665603ULL
diff --git a/include/cst_version.h b/include/cst_version.h
index 75d6277..ec6ac5e 100644
--- a/include/cst_version.h
+++ b/include/cst_version.h
@@ -1,6 +1,14 @@
 #ifndef CST_VERSION_H
 #define CST_VERSION_H
 
-#define CST_VERSION "0.5.0"
+#define CST_VERSION_MAJOR 0
+#define CST_VERSION_MINOR 6
+#define CST_VERSION_PATCH 0
+
+#define CST_VERSION_STR_(x) #x
+#define CST_VERSION_STR(x) CST_VERSION_STR_(x)
+#define CST_VERSION                                                            \
+  CST_VERSION_STR(CST_VERSION_MAJOR)                                           \
+  "." CST_VERSION_STR(CST_VERSION_MINOR) "." CST_VERSION_STR(CST_VERSION_PATCH)
 
 #endif
diff --git a/include/os_compat.h b/include/os_compat.h
index 4d72c7f..c70b351 100644
--- a/include/os_compat.h
+++ b/include/os_compat.h
@@ -22,6 +22,28 @@ int os_realpath(const char *path, char *out, size_t out_sz);
 /* True if path is under root (after realpath/norm). Trailing slash rules apply. */
 int os_path_under(const char *root, const char *path);
 
+/* --- directory listing / file type --- */
+typedef struct os_dir os_dir_t;
+typedef struct {
+  const char *name; /* UTF-8; valid until the next os_dir_next */
+  int is_dir;
+  int is_link; /* symlink, or a junction on Windows (not followed) */
+} os_dirent_t;
+os_dir_t *os_dir_open(const char *path);
+/* Next entry, skipping "." and ".."; NULL at the end. */
+const os_dirent_t *os_dir_next(os_dir_t *d);
+void os_dir_close(os_dir_t *d);
+
+typedef struct {
+  int is_dir, is_reg, is_link;
+  long long size;
+  double mtime; /* seconds since the epoch */
+} os_stat_t;
+/* Like lstat(2): a link is reported as a link, not followed. */
+int os_lstat(const char *path, os_stat_t *st);
+/* Replace `to` if it exists (atomic where the OS allows). */
+int os_rename_replace(const char *from, const char *to);
+
 /* --- dirs / config --- */
 int os_mkdir(const char *path, int mode);
 int os_mkdir_p(const char *path, int mode);
@@ -67,6 +89,28 @@ int os_run_shell_ex(const char *cwd, const char *cmd, size_t max_out,
                     os_run_result_t *r, os_child_hook_fn child_hook,
                     void *ud);
 
+#ifdef _WIN32
+/* Windows: run under `token` (a primary token, e.g. the Low-IL sandbox
+ * token; NULL = ours) with env_add "KEY=VALUE" entries layered on the
+ * inherited environment. Every child runs in a kill-on-close Job Object, so
+ * timeouts and cancels end the whole process tree. */
+int os_run_capture_token(const char *cwd, const char *const argv[],
+                         size_t max_out, os_run_result_t *r, void *token,
+                         const char *const env_add[]);
+/* os_run_shell_c under token, with env_add. */
+int os_run_shell_token(const char *cwd, const char *cmd, size_t max_out,
+                       os_run_result_t *r, void *token,
+                       const char *const env_add[]);
+/* "Windows 10.0.26100 x86_64" (the real version, not the compat shim's). */
+void os_windows_version(char *out, size_t n);
+/* Sets the mandatory-label SACL, e.g. "S:(ML;OICI;NW;;;LW)"; 0 / -1. */
+int os_win_set_label(const char *path, const char *sddl);
+/* The explicit (not inherited) label as SDDL, "S:" when there is none. */
+int os_win_get_label(const char *path, char *out, size_t n);
+/* CF_UNICODE_TEXT clipboard (the console may not do OSC 52). */
+int os_clipboard_set(const char *utf8, size_t n);
+#endif
+
 /* Child processes get stdin=/dev/null, their own process group, and are
  * killed after the timeout (CST_SHELL_TIMEOUT seconds, default 120) or when
  * *flag becomes non-zero. Exit code 124 = timeout, 130 = cancelled. */
@@ -80,7 +124,7 @@ int os_get_run_timeout(void);
  * the inherited environment (NULL-terminated, may be NULL). */
 typedef struct {
 #ifdef _WIN32
-  void *proc, *in_w, *out_r;
+  void *proc, *in_w, *out_r, *job;
 #else
   int pid, in_fd, out_fd;
 #endif
@@ -106,10 +150,30 @@ void os_run_parallel(os_task_fn fn, void *const args[], int n);
 /* Monotonic milliseconds (arbitrary epoch). */
 double os_now_ms(void);
 
+/* --- text encoding ---
+ * cst-agent is UTF-8 throughout. On Windows the manifest makes UTF-8 the
+ * process code page; os_console_init() also switches the console to UTF-8
+ * (restored at exit), sets a UTF-8 C locale and asks Python children for
+ * UTF-8. Returns -1 when the process code page is not UTF-8 (pre-1903
+ * Windows); no-op returning 0 elsewhere. */
+int os_console_init(void);
+/* Child output that is not valid UTF-8, decoded from the console/OEM/ANSI
+ * code page: malloc'd UTF-8, or NULL when s is already UTF-8 (or not on
+ * Windows). */
+char *os_output_to_utf8(const char *s, size_t n, size_t *out_len);
+#ifdef _WIN32
+#include <wchar.h>
+/* malloc'd conversions; NULL on invalid input or allocation failure */
+wchar_t *os_utf8_to_wide(const char *s);
+char *os_wide_to_utf8(const wchar_t *w);
+#endif
+
 /* --- misc --- */
 void os_localtime(const time_t *t, struct tm *out);
 int os_getpid(void);
-int os_chmod_private(const char *path); /* best-effort 0600; no-op/ok on Win */
+/* 0600; on Windows a Medium no-read-up label, so Low-IL children (the
+ * shell sandbox) cannot read the file. */
+int os_chmod_private(const char *path);
 
 /* --- UTF-8 --------------------------------------------------------------
  * Encode one code point as UTF-8, independent of the C locale.
diff --git a/res/windows/cst-agent.manifest b/res/windows/cst-agent.manifest
new file mode 100644
index 0000000..8e464ca
--- /dev/null
+++ b/res/windows/cst-agent.manifest
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly manifestVersion="1.0" xmlns="urn:schemas-microsoft-com:asm.v1"
+          xmlns:asmv3="urn:schemas-microsoft-com:asm.v3">
+  <assemblyIdentity type="win32" name="cst-agent" version="1.0.0.0"/>
+  <asmv3:application>
+    <asmv3:windowsSettings>
+      <activeCodePage xmlns="http://schemas.microsoft.com/SMI/2019/WindowsSettings">UTF-8</activeCodePage>
+      <longPathAware xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">true</longPathAware>
+    </asmv3:windowsSettings>
+  </asmv3:application>
+  <trustInfo xmlns="urn:schemas-microsoft-com:asm.v3">
+    <security>
+      <requestedPrivileges>
+        <requestedExecutionLevel level="asInvoker" uiAccess="false"/>
+      </requestedPrivileges>
+    </security>
+  </trustInfo>
+  <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
+    <application>
+      <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}"/>
+    </application>
+  </compatibility>
+</assembly>
diff --git a/res/windows/cst-agent.rc b/res/windows/cst-agent.rc
new file mode 100644
index 0000000..78633a6
--- /dev/null
+++ b/res/windows/cst-agent.rc
@@ -0,0 +1,29 @@
+#include <winver.h>
+#include "cst_version.h"
+
+1 24 "cst-agent.manifest"
+
+VS_VERSION_INFO VERSIONINFO
+FILEVERSION CST_VERSION_MAJOR, CST_VERSION_MINOR, CST_VERSION_PATCH, 0
+PRODUCTVERSION CST_VERSION_MAJOR, CST_VERSION_MINOR, CST_VERSION_PATCH, 0
+FILEOS VOS_NT_WINDOWS32
+FILETYPE VFT_APP
+BEGIN
+  BLOCK "StringFileInfo"
+  BEGIN
+    BLOCK "040904B0"
+    BEGIN
+      VALUE "CompanyName", "WHC"
+      VALUE "FileDescription", "CST agent"
+      VALUE "FileVersion", CST_VERSION
+      VALUE "InternalName", "cst-agent"
+      VALUE "OriginalFilename", "cst-agent.exe"
+      VALUE "ProductName", "CST agent"
+      VALUE "ProductVersion", CST_VERSION
+    END
+  END
+  BLOCK "VarFileInfo"
+  BEGIN
+    VALUE "Translation", 0x409, 1200
+  END
+END
diff --git a/scripts/bootstrap_msys2.sh b/scripts/bootstrap_msys2.sh
new file mode 100755
index 0000000..0ad8036
--- /dev/null
+++ b/scripts/bootstrap_msys2.sh
@@ -0,0 +1,58 @@
+#!/usr/bin/env bash
+# Native Windows build from an MSYS2 UCRT64 shell (https://www.msys2.org/).
+#   scripts/bootstrap_msys2.sh [repo-dir]
+# Installs the UCRT64 toolchain with pacman, builds the same pinned static
+# deps as the Linux cross build (curl with Schannel, ncurses with the Windows
+# console patches, busybox-w32 Unicode), then a static cst-agent.exe with the
+# UTF-8 manifest, runs the tests and packages dist/windows-x86_64/.
+# CST_SKIP_TESTS=1 skips ctest.
+set -euo pipefail
+
+if [[ "${MSYSTEM:-}" != UCRT64 ]]; then
+  echo "run this from the MSYS2 UCRT64 shell: the UTF-8 manifest needs the" \
+    "UCRT runtime (MINGW64 links msvcrt)" >&2
+  exit 1
+fi
+
+REPO_URL="${CST_AGENT_REPO:-https://git.whcself.xyz/WHC/CST-agent.git}"
+DIR="${1:-}"
+if [[ -z "$DIR" ]]; then
+  if [[ -f CMakeLists.txt && -d src ]]; then
+    DIR="$(pwd)"
+  else
+    DIR="CST-agent"
+  fi
+fi
+
+pacman -S --needed --noconfirm \
+  mingw-w64-ucrt-x86_64-gcc mingw-w64-ucrt-x86_64-cmake \
+  mingw-w64-ucrt-x86_64-ninja make git patch tar perl zip diffutils
+
+if [[ ! -f "$DIR/CMakeLists.txt" ]]; then
+  echo "==> git clone $REPO_URL -> $DIR"
+  git clone "$REPO_URL" "$DIR"
+fi
+cd "$DIR"
+
+# third-party script: unprefixed native tools
+export MINGW_HOST= BUILD_CC=gcc
+[[ -f third_party/prefix-mingw/lib/libcurl.a ]] || scripts/build_third_party_mingw.sh curl
+[[ -f third_party/prefix-mingw/lib/libncursesw.a ]] || scripts/build_third_party_mingw.sh ncurses
+if [[ ! -f third_party/busybox/busybox.exe ]]; then
+  scripts/build_third_party_mingw.sh busybox-w32 || scripts/fetch_busybox_w32.sh
+fi
+
+echo "==> cmake (MSYS2 UCRT64, static, TUI)"
+cmake -S . -B build-msys2 -G Ninja -DCMAKE_BUILD_TYPE=Release \
+  -DCMAKE_PREFIX_PATH="$PWD/third_party/prefix-mingw" \
+  -DCST_WIN_STATIC=ON -DCST_BUILD_TUI=ON
+cmake --build build-msys2
+
+if [[ -z "${CST_SKIP_TESTS:-}" ]]; then
+  echo "==> ctest"
+  cp -f third_party/busybox/busybox.exe build-msys2/
+  ctest --test-dir build-msys2 --output-on-failure
+fi
+
+echo "==> package"
+CST_WIN_BUILD=build-msys2 scripts/package_windows.sh
diff --git a/scripts/bootstrap_windows.sh b/scripts/bootstrap_windows.sh
index 1e31209..c031116 100755
--- a/scripts/bootstrap_windows.sh
+++ b/scripts/bootstrap_windows.sh
@@ -1,11 +1,13 @@
 #!/usr/bin/env bash
-# One-shot on a Linux host: cross-build Windows x86_64 release (MinGW).
-# Output: dist/windows-x86_64/  — copy that folder to a Windows machine.
+# Linux host: cross-build the Windows x86_64 release (mingw-w64, UCRT, static).
+#   scripts/bootstrap_windows.sh [repo-dir]
+# With Nix the toolchain comes from shell-win.nix; otherwise x86_64-w64-mingw32-gcc
+# (UCRT flavour, with winpthreads), cmake, ninja, git and perl must be installed.
+# Output: dist/windows-x86_64/ and dist/cst-agent-VERSION-windows-x86_64.zip
 set -euo pipefail
 
 REPO_URL="${CST_AGENT_REPO:-https://git.whcself.xyz/WHC/CST-agent.git}"
 DIR="${1:-}"
-
 if [[ -z "$DIR" ]]; then
   if [[ -f CMakeLists.txt && -d src ]]; then
     DIR="$(pwd)"
@@ -13,36 +15,33 @@ if [[ -z "$DIR" ]]; then
     DIR="CST-agent"
   fi
 fi
-
 if [[ ! -f "$DIR/CMakeLists.txt" ]]; then
   echo "==> git clone $REPO_URL -> $DIR"
   git clone "$REPO_URL" "$DIR"
 fi
 cd "$DIR"
 
-need() { command -v "$1" >/dev/null || { echo "missing $1 (install mingw-w64 gcc cmake git)" >&2; exit 1; }; }
-need git; need cmake; need x86_64-w64-mingw32-gcc
+if ! command -v x86_64-w64-mingw32-gcc >/dev/null && [[ -z "${IN_NIX_SHELL:-}" ]] &&
+  command -v nix-shell >/dev/null; then
+  exec nix-shell shell-win.nix --run "$(printf '%q ' "$0" "$PWD")"
+fi
 
-echo "==> third-party (curl Schannel + PDCurses + busybox-w32)"
-chmod +x scripts/*.sh 2>/dev/null || true
-./scripts/build_third_party_mingw.sh all
+need() { command -v "$1" >/dev/null || { echo "missing $1 (mingw-w64 UCRT gcc, cmake, ninja, git, perl)" >&2; exit 1; }; }
+need git; need cmake; need ninja; need perl; need x86_64-w64-mingw32-gcc
+if ! printf '#include <stdio.h>\n' | x86_64-w64-mingw32-gcc -dM -E - | grep -qw _UCRT; then
+  echo "x86_64-w64-mingw32-gcc targets msvcrt; the UTF-8 manifest needs a UCRT toolchain" >&2
+  exit 1
+fi
 
-echo "==> cmake Windows TUI"
-cmake -B build-win-tui \
+[[ -f third_party/prefix-mingw/lib/libcurl.a ]] || scripts/build_third_party_mingw.sh curl
+[[ -f third_party/prefix-mingw/lib/libncursesw.a ]] || scripts/build_third_party_mingw.sh ncurses
+[[ -f third_party/busybox/busybox.exe ]] || scripts/build_third_party_mingw.sh busybox-w32
+
+echo "==> cmake (Windows, TUI)"
+cmake -S . -B build-win-tui -G Ninja \
   -DCMAKE_TOOLCHAIN_FILE=cmake/mingw-w64-x86_64.cmake \
-  -DCST_BUILD_TUI=ON \
-  -DCMAKE_PREFIX_PATH="$PWD/third_party/prefix-mingw" \
-  -DPDCurses_ROOT="$PWD/third_party/prefix-mingw"
-cmake --build build-win-tui -j"$(nproc 2>/dev/null || echo 4)"
+  -DCMAKE_BUILD_TYPE=Release -DCST_BUILD_TUI=ON
+cmake --build build-win-tui
 
 echo "==> package"
-./scripts/package_windows.sh
-
-echo
-echo "OK: dist/windows-x86_64/"
-echo "Copy that folder to Windows, then:"
-echo "  set OPENAI_API_KEY=sk-..."
-echo "  set OPENAI_BASE_URL=https://api.openai.com/v1"
-echo "  set OPENAI_MODEL=gpt-4.1-mini"
-echo "  cst-agent.exe --workspace ."
-echo "See docs/env_openai.md and docs/README-windows.md"
+scripts/package_windows.sh
diff --git a/scripts/build_third_party_mingw.sh b/scripts/build_third_party_mingw.sh
index f51e05b..5874d3b 100755
--- a/scripts/build_third_party_mingw.sh
+++ b/scripts/build_third_party_mingw.sh
@@ -1,139 +1,127 @@
 #!/usr/bin/env bash
-# Build third-party deps for Windows MinGW cross + optional Unix busybox.
-# Sources:
-#   busybox-w32: https://github.com/rmyorston/busybox-w32.git
-#   busybox:     https://github.com/mirror/busybox.git
-#   curl:        https://github.com/curl/curl.git (Windows via Schannel)
-#   PDCurses:    https://github.com/wmcbrine/PDCurses.git
+# Build pinned third-party deps for Windows x86_64 (mingw-w64, UCRT) into
+# third_party/prefix-mingw, plus busybox-w32 into third_party/busybox.
+#   nix-shell shell-win.nix --run 'scripts/build_third_party_mingw.sh [all|curl|pdcurses|ncurses|busybox-w32]'
+# Works the same from an MSYS2 UCRT64 shell (MINGW_HOST= uses unprefixed tools).
 set -euo pipefail
 ROOT="$(cd "$(dirname "$0")/.." && pwd)"
 TP="$ROOT/third_party"
-HOST="${MINGW_HOST:-x86_64-w64-mingw32}"
+PREFIX="$TP/prefix-mingw"
+HOST="${MINGW_HOST-x86_64-w64-mingw32}"
+T="${HOST:+$HOST-}"
 JOBS="${JOBS:-$(nproc 2>/dev/null || echo 4)}"
-mkdir -p "$TP"
 
+CURL_TAG=curl-8_22_0
+PDCURSES_TAG=3.9
+NCURSES_VER=6.6
+BUSYBOX_W32_REV=9b50a1e
+
+mkdir -p "$TP" "$PREFIX"
 need_cmd() { command -v "$1" >/dev/null || { echo "missing: $1" >&2; exit 1; }; }
 need_cmd git
 need_cmd make
-need_cmd "${HOST}-gcc"
+need_cmd "${T}gcc"
 
-clone_or_update() {
-  local url="$1" dir="$2"
-  if [[ -d "$dir/.git" ]]; then
-    git -C "$dir" fetch --depth 1 origin 2>/dev/null || true
-    git -C "$dir" pull --ff-only 2>/dev/null || true
-  else
-    git clone --depth 1 "$url" "$dir"
+checkout() { # url dir rev
+  local url="$1" dir="$2" rev="$3"
+  [[ -d "$dir/.git" ]] || git clone -q --filter=blob:none "$url" "$dir"
+  if ! git -C "$dir" rev-parse -q --verify "$rev^{commit}" >/dev/null; then
+    git -C "$dir" fetch -q --tags origin
   fi
+  git -C "$dir" checkout -q --detach "$rev"
 }
 
-# --- curl (static, Schannel) ---
-build_curl_mingw() {
-  clone_or_update https://github.com/curl/curl.git "$TP/curl"
-  cd "$TP/curl"
-  if [[ ! -f configure ]]; then
-    autoreconf -fi 2>/dev/null || true
-  fi
-  # Prefer cmake for curl modern tree
-  rm -rf build-mingw
-  cmake -B build-mingw -G "Unix Makefiles" \
-    -DCMAKE_SYSTEM_NAME=Windows \
-    -DCMAKE_C_COMPILER="${HOST}-gcc" \
-    -DCMAKE_RC_COMPILER="${HOST}-windres" \
-    -DCMAKE_INSTALL_PREFIX="$TP/prefix-mingw" \
-    -DBUILD_SHARED_LIBS=OFF \
-    -DCURL_USE_SCHANNEL=ON \
-    -DCURL_USE_OPENSSL=OFF \
-    -DCURL_DISABLE_LDAP=ON \
-    -DCURL_USE_LIBPSL=OFF \
-    -DCURL_ZLIB=OFF \
-    -DCURL_BROTLI=OFF \
-    -DCURL_ZSTD=OFF \
-    -DUSE_NGHTTP2=OFF \
-    -DBUILD_CURL_EXE=OFF \
-    -DBUILD_TESTING=OFF \
-    -DHTTP_ONLY=OFF
-  cmake --build build-mingw -j"$JOBS"
-  cmake --install build-mingw
-  echo "curl installed -> $TP/prefix-mingw"
+build_curl() {
+  checkout https://github.com/curl/curl.git "$TP/curl" "$CURL_TAG"
+  rm -rf "$TP/curl/build-mingw"
+  local tc=()
+  [[ -n "$HOST" ]] && tc=(-DCMAKE_SYSTEM_NAME=Windows -DCMAKE_C_COMPILER="${T}gcc" -DCMAKE_RC_COMPILER="${T}windres")
+  cmake -S "$TP/curl" -B "$TP/curl/build-mingw" -G Ninja "${tc[@]}" \
+    -DCMAKE_BUILD_TYPE=Release \
+    -DCMAKE_INSTALL_PREFIX="$PREFIX" \
+    -DBUILD_SHARED_LIBS=OFF -DBUILD_STATIC_LIBS=ON \
+    -DCURL_USE_SCHANNEL=ON -DCURL_USE_OPENSSL=OFF \
+    -DCURL_WINDOWS_SSPI=ON -DENABLE_UNICODE=ON \
+    -DCURL_DISABLE_LDAP=ON -DCURL_USE_LIBPSL=OFF -DCURL_USE_LIBSSH2=OFF \
+    -DUSE_LIBIDN2=OFF -DUSE_NGHTTP2=OFF \
+    -DCURL_ZLIB=OFF -DCURL_BROTLI=OFF -DCURL_ZSTD=OFF \
+    -DBUILD_CURL_EXE=OFF -DBUILD_TESTING=OFF -DBUILD_EXAMPLES=OFF \
+    -DBUILD_LIBCURL_DOCS=OFF -DBUILD_MISC_DOCS=OFF -DENABLE_CURL_MANUAL=OFF
+  cmake --build "$TP/curl/build-mingw" -j"$JOBS"
+  cmake --install "$TP/curl/build-mingw"
+  echo "curl $CURL_TAG -> $PREFIX"
 }
 
-# --- PDCurses ---
-build_pdcurses_mingw() {
-  clone_or_update https://github.com/wmcbrine/PDCurses.git "$TP/PDCurses"
+build_pdcurses() {
+  checkout https://github.com/wmcbrine/PDCurses.git "$TP/PDCurses" "$PDCURSES_TAG"
   cd "$TP/PDCurses/wincon"
-  make -f Makefile clean 2>/dev/null || true
-  make -f Makefile \
-    CC="${HOST}-gcc" \
-    LINK="${HOST}-gcc" \
-    CFLAGS="-O2 -I.. -DPDC_WIDE -DPDC_FORCE_UTF8" \
-    LIBEXE="${HOST}-ar" \
-    LIBFLAGS=rcv \
-    pdcurses.a
-  mkdir -p "$TP/prefix-mingw/include" "$TP/prefix-mingw/lib"
-  cp -f ../curses.h "$TP/prefix-mingw/include/"
-  [[ -f ../panel.h ]] && cp -f ../panel.h "$TP/prefix-mingw/include/" || true
-  cp -f pdcurses.a "$TP/prefix-mingw/lib/libpdcurses.a"
-  # Also install as curses for find_library
-  cp -f pdcurses.a "$TP/prefix-mingw/lib/libcurses.a"
-  echo "PDCurses -> $TP/prefix-mingw"
+  make clean >/dev/null 2>&1 || true
+  make -j"$JOBS" CC="${T}gcc" AR="${T}ar" STRIP="${T}strip" WIDE=Y UTF8=Y pdcurses.a
+  mkdir -p "$PREFIX/include/pdcurses" "$PREFIX/lib"
+  cp -f ../curses.h ../panel.h "$PREFIX/include/pdcurses/"
+  cp -f pdcurses.a "$PREFIX/lib/libpdcurses.a"
+  echo "PDCurses $PDCURSES_TAG -> $PREFIX"
+}
+
+build_ncurses() {
+  local src="$TP/ncurses-$NCURSES_VER" tgz="$TP/ncurses-$NCURSES_VER.tar.gz"
+  [[ -f "$tgz" ]] || curl -fL -o "$tgz" \
+    "https://invisible-island.net/archives/ncurses/ncurses-$NCURSES_VER.tar.gz"
+  [[ -d "$src" ]] || tar -C "$TP" -xzf "$tgz"
+  local pf
+  for pf in "$ROOT"/scripts/patches/ncurses-"$NCURSES_VER"-*.patch; do
+    [[ -e "$pf" ]] || continue
+    patch -d "$src" -p1 -R --dry-run -s -f <"$pf" >/dev/null 2>&1 && continue
+    if ! patch -d "$src" -p1 --dry-run -s -f <"$pf" >/dev/null 2>&1; then
+      echo "ncurses: $src has another version of $(basename "$pf"); re-extracting"
+      rm -rf "$src"
+      tar -C "$TP" -xzf "$tgz"
+    fi
+    patch -d "$src" -p1 -s <"$pf"
+  done
+  rm -rf "$src/build-mingw"
+  mkdir -p "$src/build-mingw"
+  cd "$src/build-mingw"
+  ../configure --host="${HOST:-x86_64-w64-mingw32}" --prefix="$PREFIX" \
+    --without-ada --without-cxx --without-cxx-binding --without-manpages \
+    --without-progs --without-tests --without-debug --without-shared \
+    --enable-widec --enable-sp-funcs --enable-term-driver \
+    --enable-interop --disable-home-terminfo --disable-db-install \
+    --with-fallbacks=ms-terminal,xterm-256color --without-pkg-config \
+    --disable-pc-files --with-build-cc="${BUILD_CC:-cc}" >/dev/null
+  make -j"$JOBS" libs >/dev/null
+  make install.libs >/dev/null
+  echo "ncurses $NCURSES_VER -> $PREFIX"
 }
 
-# --- busybox-w32 ---
 build_busybox_w32() {
-  clone_or_update https://github.com/rmyorston/busybox-w32.git "$TP/busybox-w32"
+  checkout https://github.com/rmyorston/busybox-w32.git "$TP/busybox-w32" "$BUSYBOX_W32_REV"
   cd "$TP/busybox-w32"
-  # configs: try mingw64 defconfig
-  if [[ -f configs/mingw64_defconfig ]]; then
-    make mingw64_defconfig
-  elif [[ -f configs/mingw_defconfig ]]; then
-    make mingw_defconfig
-  else
-    make defconfig
-  fi
-  # Cross compile
-  make -j"$JOBS" CROSS_COMPILE="${HOST}-" \
-    CONFIG_EXTRA_CFLAGS="-O2" \
-    busybox.exe 2>&1 || make -j"$JOBS" CROSS_COMPILE="${HOST}-"
+  make -s mingw64u_defconfig >/dev/null
+  make -s -j"$JOBS" CROSS_COMPILE="$T" </dev/null
   mkdir -p "$TP/busybox"
-  if [[ -f busybox.exe ]]; then
-    cp -f busybox.exe "$TP/busybox/busybox.exe"
-  else
-    find . -name 'busybox.exe' | head -1 | xargs -I{} cp -f {} "$TP/busybox/busybox.exe"
-  fi
-  cat > "$TP/busybox/LICENSE.busybox" << 'EOF'
-BusyBox is GPLv2. Source: https://github.com/rmyorston/busybox-w32
-Upstream BusyBox: https://github.com/mirror/busybox
+  cp -f busybox.exe "$TP/busybox/busybox.exe"
+  cat >"$TP/busybox/LICENSE.busybox" <<EOF
+BusyBox is GPLv2. This busybox.exe is busybox-w32 ($BUSYBOX_W32_REV, Unicode build):
+https://github.com/rmyorston/busybox-w32
+Upstream BusyBox: https://busybox.net/
 EOF
   ls -la "$TP/busybox/busybox.exe"
 }
 
-# --- Unix busybox (optional, for Linux/Termux side-by-side bundle) ---
-build_busybox_unix() {
-  clone_or_update https://github.com/mirror/busybox.git "$TP/busybox-src"
-  cd "$TP/busybox-src"
-  make defconfig
-  # Keep applets reasonable; enable ash + diff
-  make -j"$JOBS" busybox
-  mkdir -p "$TP/busybox"
-  cp -f busybox "$TP/busybox/busybox"
-  echo "unix busybox -> $TP/busybox/busybox"
-}
-
-TARGETS="${1:-all}"
-case "$TARGETS" in
-  curl) build_curl_mingw ;;
-  pdcurses) build_pdcurses_mingw ;;
-  busybox-w32) build_busybox_w32 ;;
-  busybox-unix) build_busybox_unix ;;
-  all)
-    build_curl_mingw
-    build_pdcurses_mingw
-    build_busybox_w32
-    ;;
-  *)
-    echo "usage: $0 [all|curl|pdcurses|busybox-w32|busybox-unix]"
-    exit 1
-    ;;
+case "${1:-all}" in
+curl) build_curl ;;
+pdcurses) build_pdcurses ;;
+ncurses) build_ncurses ;;
+busybox-w32) build_busybox_w32 ;;
+all)
+  build_curl
+  build_ncurses
+  build_busybox_w32
+  ;;
+*)
+  echo "usage: $0 [all|curl|pdcurses|ncurses|busybox-w32]"
+  exit 1
+  ;;
 esac
 echo "DONE"
diff --git a/scripts/install_windows.ps1 b/scripts/install_windows.ps1
new file mode 100644
index 0000000..5d4a888
--- /dev/null
+++ b/scripts/install_windows.ps1
@@ -0,0 +1,106 @@
+# Install or update CST-Agent on Windows from a Gitea release.
+#
+#   irm https://git.whcself.xyz/WHC/CST-agent/raw/branch/main/scripts/install_windows.ps1 | iex
+#   powershell -ExecutionPolicy Bypass -File install_windows.ps1 [-Version 0.6.0] [-Prefix DIR] [-Zip FILE] [-NoPath]
+#
+# Installs into %LOCALAPPDATA%\Programs\cst-agent (no admin rights needed),
+# adds it to the user PATH and leaves cst-agent-update.cmd beside the exe,
+# which reruns this script for that folder. Environment overrides:
+# CST_VERSION, CST_PREFIX, CST_GITEA (server URL), CST_REPO (owner/name).
+# Needs Windows 10 1903+ / Server 2022+ (UTF-8 process code page).
+# Keep this file ASCII: Windows PowerShell 5.1 reads BOM-less scripts in the
+# ANSI code page.
+param(
+  [string]$Version = $env:CST_VERSION,
+  [string]$Prefix = $env:CST_PREFIX,
+  [string]$Zip = "",
+  [switch]$NoPath
+)
+$ErrorActionPreference = "Stop"
+$ProgressPreference = "SilentlyContinue"
+[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
+
+$Server = if ($env:CST_GITEA) { $env:CST_GITEA.TrimEnd("/") } else { "https://git.whcself.xyz" }
+$Repo = if ($env:CST_REPO) { $env:CST_REPO } else { "WHC/CST-agent" }
+if (-not $Prefix) { $Prefix = Join-Path $env:LOCALAPPDATA "Programs\cst-agent" }
+$Prefix = [IO.Path]::GetFullPath($Prefix)
+
+$build = [Environment]::OSVersion.Version.Build
+if ($build -lt 18362) {
+  throw "CST-Agent needs Windows 10 1903 (build 18362) or newer; this is build $build."
+}
+
+$work = Join-Path ([IO.Path]::GetTempPath()) ("cst-agent-install-" + [Guid]::NewGuid().ToString("N"))
+New-Item -ItemType Directory -Force $work | Out-Null
+try {
+  if (-not $Zip) {
+    $api = "$Server/api/v1/repos/$Repo/releases"
+    $url = if (-not $Version -or $Version -eq "latest") { "$api/latest" } else { "$api/tags/v$($Version.TrimStart('v'))" }
+    Write-Host "==> $url"
+    try {
+      $rel = Invoke-RestMethod -Uri $url -UseBasicParsing
+    } catch {
+      throw "no release found at $url ($($_.Exception.Message))"
+    }
+    $asset = $rel.assets | Where-Object { $_.name -like "*-windows-x86_64.zip" } | Select-Object -First 1
+    if (-not $asset) { throw "release $($rel.tag_name) has no *-windows-x86_64.zip" }
+    $Zip = Join-Path $work $asset.name
+    Write-Host "==> download $($asset.name) ($($rel.tag_name))"
+    Invoke-WebRequest -Uri $asset.browser_download_url -OutFile $Zip -UseBasicParsing
+    $sum = $rel.assets | Where-Object { $_.name -eq "$($asset.name).sha256" } | Select-Object -First 1
+    if ($sum) {
+      $sumFile = Join-Path $work $sum.name
+      Invoke-WebRequest -Uri $sum.browser_download_url -OutFile $sumFile -UseBasicParsing
+      $want = ((Get-Content $sumFile -Raw).Trim() -split "\s+")[0].ToLower()
+      $got = (Get-FileHash -Algorithm SHA256 $Zip).Hash.ToLower()
+      if ($want -ne $got) { throw "sha256 mismatch for $($asset.name): expected $want, got $got" }
+      Write-Host "==> sha256 ok"
+    }
+  }
+
+  Expand-Archive -Path $Zip -DestinationPath $work -Force
+  $src = Join-Path $work "windows-x86_64"
+  if (-not (Test-Path (Join-Path $src "cst-agent.exe"))) { throw "$Zip has no windows-x86_64\cst-agent.exe" }
+
+  New-Item -ItemType Directory -Force $Prefix | Out-Null
+  # A running exe cannot be overwritten but can be renamed out of the way.
+  foreach ($name in @("cst-agent.exe", "busybox.exe")) {
+    $dst = Join-Path $Prefix $name
+    $old = "$dst.old"
+    if (Test-Path $old) { Remove-Item -Force $old -ErrorAction SilentlyContinue }
+    if (Test-Path $dst) {
+      try { Remove-Item -Force $dst } catch { Rename-Item -Force $dst "$name.old" }
+    }
+  }
+  Copy-Item -Force -Recurse (Join-Path $src "*") $Prefix
+
+  $update = Join-Path $Prefix "cst-agent-update.cmd"
+  if (-not (Test-Path $update)) {
+    Set-Content -Encoding Ascii -Path $update -Value @(
+      "@echo off",
+      "rem Update CST-Agent in this folder from the latest release.",
+      "powershell -NoProfile -ExecutionPolicy Bypass -File `"%~dp0install_windows.ps1`" -Prefix `"%~dp0.`" %*"
+    )
+  }
+  if (-not (Test-Path (Join-Path $Prefix "install_windows.ps1")) -and $PSCommandPath) {
+    Copy-Item -Force $PSCommandPath (Join-Path $Prefix "install_windows.ps1")
+  }
+
+  if (-not $NoPath) {
+    $userPath = [Environment]::GetEnvironmentVariable("Path", "User")
+    $parts = @($userPath -split ";" | Where-Object { $_ })
+    if (-not ($parts | Where-Object { $_.TrimEnd("\") -ieq $Prefix.TrimEnd("\") })) {
+      [Environment]::SetEnvironmentVariable("Path", (($parts + $Prefix) -join ";"), "User")
+      Write-Host "==> added $Prefix to the user PATH (open a new terminal to use it)"
+    }
+    if (-not (($env:Path -split ";") | Where-Object { $_.TrimEnd("\") -ieq $Prefix.TrimEnd("\") })) {
+      $env:Path = "$env:Path;$Prefix"
+    }
+  }
+
+  $ver = (& (Join-Path $Prefix "cst-agent.exe") --version) 2>&1 | Select-Object -First 1
+  Write-Host "==> installed $ver in $Prefix"
+  Write-Host "Run 'cst-agent' inside a project folder; update later with 'cst-agent-update'."
+} finally {
+  Remove-Item -Recurse -Force $work -ErrorAction SilentlyContinue
+}
diff --git a/scripts/package_windows.sh b/scripts/package_windows.sh
index 2ad57e1..ee7a39b 100755
--- a/scripts/package_windows.sh
+++ b/scripts/package_windows.sh
@@ -1,18 +1,38 @@
 #!/usr/bin/env bash
-# Assemble dist/windows-x86_64 from MinGW TUI build + busybox.
+# Assemble dist/windows-x86_64/ and dist/cst-agent-VERSION-windows-x86_64.zip
+# from the cross build (build-win-tui, else build-win; CST_WIN_BUILD=DIR
+# picks another, e.g. build-msys2) and busybox-w32.
 set -euo pipefail
 ROOT="$(cd "$(dirname "$0")/.." && pwd)"
 REL="$ROOT/dist/windows-x86_64"
-EXE="$ROOT/build-win-tui/cst-agent.exe"
-[[ -f "$EXE" ]] || EXE="$ROOT/build-win/cst-agent.exe"
+if [[ -n "${CST_WIN_BUILD:-}" ]]; then
+  EXE="$ROOT/$CST_WIN_BUILD/cst-agent.exe"
+else
+  EXE="$ROOT/build-win-tui/cst-agent.exe"
+  [[ -f "$EXE" ]] || EXE="$ROOT/build-win/cst-agent.exe"
+fi
 BB="$ROOT/third_party/busybox/busybox.exe"
-DLL="/usr/x86_64-w64-mingw32/bin/libwinpthread-1.dll"
+[[ -f "$EXE" ]] || { echo "no cst-agent.exe; build first" >&2; exit 1; }
+[[ -f "$BB" ]] || { echo "no busybox.exe; scripts/build_third_party_mingw.sh busybox-w32" >&2; exit 1; }
 
+ver="$(sed -n 's/^#define CST_VERSION_\(MAJOR\|MINOR\|PATCH\) \([0-9]*\)$/\2/p' "$ROOT/include/cst_version.h" | paste -sd.)"
+strip="${MINGW_HOST-x86_64-w64-mingw32}"
+strip="${strip:+$strip-}strip"
+command -v "$strip" >/dev/null || strip=strip # MSYS2: unprefixed
+
+rm -rf "$REL"
 mkdir -p "$REL"
 cp -f "$EXE" "$REL/cst-agent.exe"
+"$strip" "$REL/cst-agent.exe"
 cp -f "$BB" "$REL/busybox.exe"
 cp -f "$ROOT/third_party/busybox/LICENSE.busybox" "$REL/"
-cp -f "$ROOT/docs/README-windows.md" "$REL/"
-[[ -f "$DLL" ]] && cp -f "$DLL" "$REL/"
+cp -f "$ROOT/docs/README-windows.md" "$REL/README.md"
+cp -f "$ROOT/scripts/windows/cst-agent-update.cmd" "$ROOT/scripts/install_windows.ps1" "$REL/"
+echo "$ver" >"$REL/VERSION"
+
+zip="$ROOT/dist/cst-agent-$ver-windows-x86_64.zip"
+rm -f "$zip"
+(cd "$ROOT/dist" && zip -qr "$zip" windows-x86_64)
+(cd "$ROOT/dist" && sha256sum "$(basename "$zip")" >"$(basename "$zip").sha256")
 ls -la "$REL"
-file "$REL/cst-agent.exe"
+echo "$zip"
diff --git a/scripts/patches/ncurses-6.6-win32-console.patch b/scripts/patches/ncurses-6.6-win32-console.patch
new file mode 100644
index 0000000..4afe941
--- /dev/null
+++ b/scripts/patches/ncurses-6.6-win32-console.patch
@@ -0,0 +1,350 @@
+--- a/ncurses/curses.priv.h
++++ b/ncurses/curses.priv.h
+@@ -2294,7 +2294,10 @@
+ #if defined(_NC_WINDOWS_NATIVE) && !defined(_NC_MSC) && !USE_NAMED_PIPES
+ /*
+  * MinGW has wide-character functions, but they do not work correctly.
++ * Declare the originals first so a later <wchar.h> is not macro-expanded.
+  */
++#include <stdlib.h>
++#include <wchar.h>
+ extern int __MINGW_NOTHROW _nc_wctomb(char *, wchar_t);
+ #define wctomb(s,wc) _nc_wctomb(s,wc)
+ #define wcrtomb(s,wc,n) _nc_wctomb(s,wc)
+--- a/ncurses/tinfo/lib_win32con.c
++++ b/ncurses/tinfo/lib_win32con.c
+@@ -653,6 +653,21 @@
+     return result;
+ }
+ 
++/* Whether handle_mouse() turns this record into an event: wheel, a button
++ * change (press or release), or a drag. */
++static bool
++mouse_wanted(const SCREEN *sp, const MOUSE_EVENT_RECORD *mer)
++{
++    int held = (int) (mer->dwButtonState & BUTTON_MASK);
++
++    if (mer->dwEventFlags & MOUSE_WHEELED)
++	return TRUE;
++    if (held != sp->_drv_mouse_new_buttons)
++	return TRUE;
++    return (mer->dwEventFlags & MOUSE_MOVED) && held
++	&& (sp->_mouse_mask & REPORT_MOUSE_POSITION);
++}
++
+ #define AdjustY() (WINCONSOLE.buffered \
+                    ? 0 \
+                    : (int) WINCONSOLE.SBI.srWindow.Top)
+@@ -661,36 +676,47 @@
+ handle_mouse(SCREEN *sp, MOUSE_EVENT_RECORD mer)
+ {
+     MEVENT work;
+-    bool result = FALSE;
++    int old_buttons;
++    int new_buttons;
+ 
+     assert(sp);
+ 
+-    sp->_drv_mouse_old_buttons = sp->_drv_mouse_new_buttons;
+-    sp->_drv_mouse_new_buttons = mer.dwButtonState & BUTTON_MASK;
++    if (sp->_drv_mouse_tail >= FIFO_SIZE)
++	return FALSE;
+ 
+-    /*
+-     * We're only interested if the button is pressed or released.
+-     * FIXME: implement continuous event-tracking.
+-     */
+-    if (sp->_drv_mouse_new_buttons != sp->_drv_mouse_old_buttons) {
+-	memset(&work, 0, sizeof(work));
++    memset(&work, 0, sizeof(work));
++    work.x = mer.dwMousePosition.X;
++    work.y = mer.dwMousePosition.Y - AdjustY();
++
++    /* the wheel reports like xterm: button 4 up, button 5 down */
++    if (mer.dwEventFlags & MOUSE_WHEELED) {
++	work.bstate = ((SHORT) HIWORD(mer.dwButtonState) > 0)
++	    ? BUTTON4_PRESSED
++	    : BUTTON5_PRESSED;
++	sp->_drv_mouse_fifo[sp->_drv_mouse_tail++] = work;
++	return TRUE;
++    }
+ 
+-	if (sp->_drv_mouse_new_buttons) {
+-	    work.bstate |= decode_mouse(sp, sp->_drv_mouse_new_buttons);
++    old_buttons = sp->_drv_mouse_new_buttons;
++    new_buttons = (int) (mer.dwButtonState & BUTTON_MASK);
++    sp->_drv_mouse_old_buttons = old_buttons;
++    sp->_drv_mouse_new_buttons = new_buttons;
++
++    if (new_buttons != old_buttons) {
++	if (new_buttons & ~old_buttons) {
++	    work.bstate = decode_mouse(sp, new_buttons & ~old_buttons);
+ 	} else {
+ 	    /* cf: BUTTON_PRESSED, BUTTON_RELEASED */
+-	    work.bstate |= (decode_mouse(sp, sp->_drv_mouse_old_buttons)
+-			    >> 1);
+-	    result = TRUE;
++	    work.bstate = decode_mouse(sp, old_buttons & ~new_buttons) >> 1;
+ 	}
+-
+-	work.x = mer.dwMousePosition.X;
+-	work.y = mer.dwMousePosition.Y - AdjustY();
+-
+-	sp->_drv_mouse_fifo[sp->_drv_mouse_tail] = work;
+-	sp->_drv_mouse_tail += 1;
++    } else if ((mer.dwEventFlags & MOUSE_MOVED) && new_buttons
++	       && (sp->_mouse_mask & REPORT_MOUSE_POSITION)) {
++	work.bstate = REPORT_MOUSE_POSITION;	/* drag */
++    } else {
++	return FALSE;
+     }
+-    return result;
++    sp->_drv_mouse_fifo[sp->_drv_mouse_tail++] = work;
++    return TRUE;
+ }
+ 
+ static int
+@@ -813,6 +839,13 @@
+     returnCode(found);
+ }
+ 
++#if USE_WIDEC_SUPPORT
++/* UTF-8 bytes of the last non-ASCII key event not yet read */
++static int utf8_pend[4];
++static int utf8_len, utf8_pos;
++static unsigned utf8_high;
++#endif
++
+ NCURSES_EXPORT(int)
+ _nc_console_twait(
+ 		     const SCREEN *sp,
+@@ -845,6 +878,14 @@
+     TR(TRACE_IEVENT, ("start twait: hdl=%p, %d milliseconds, mode: %d",
+ 		      hdl, milliseconds, mode));
+ 
++#if USE_WIDEC_SUPPORT
++    if ((mode & TW_INPUT) && utf8_pos < utf8_len) {
++	if (timeleft)
++	    *timeleft = milliseconds;
++	return TW_INPUT;
++    }
++#endif
++
+     if (milliseconds < 0)
+ 	milliseconds = NC_INFINITY;
+ 
+@@ -940,9 +981,7 @@
+ 			    continue;
+ 			case MOUSE_EVENT:
+ 			    T(("twait:event MOUSE_EVENT"));
+-			    if (decode_mouse(sp,
+-					     (inp_rec.Event.MouseEvent.dwButtonState
+-					      & BUTTON_MASK)) == 0) {
++			    if (!mouse_wanted(sp, &inp_rec.Event.MouseEvent)) {
+ 				CONSUME();
+ 			    } else if (mode & TW_MOUSE) {
+ 				code = TW_MOUSE;
+@@ -1024,6 +1063,16 @@
+ 
+     T((T_CALLED("lib_win32con::_nc_console_read(%p)"), sp));
+ 
++#if USE_WIDEC_SUPPORT
++    /* wget_wch() decodes the input as a byte stream in the locale's
++     * multibyte encoding (UTF-8), so non-ASCII UTF-16 key events are
++     * handed over one UTF-8 byte per call. */
++    if (utf8_pos < utf8_len) {
++	*buf = utf8_pend[utf8_pos++];
++	returnCode(1);
++    }
++#endif
++
+     while ((b = read_keycode(hdl, &inp_rec, 1, &nRead))) {
+ 	if (b && nRead > 0) {
+ 	    if (rc < 0)
+@@ -1034,6 +1083,36 @@
+ 		    continue;
+ 		*buf = (int) inp_rec.Event.KeyEventChar;
+ 		vk = inp_rec.Event.KeyEvent.wVirtualKeyCode;
++#if USE_WIDEC_SUPPORT
++		if (*buf >= 0x80) {
++		    unsigned cp = (unsigned) *buf;
++		    if (cp >= 0xD800 && cp < 0xDC00) {
++			utf8_high = cp;
++			continue;
++		    }
++		    if (cp >= 0xDC00 && cp < 0xE000) {
++			if (!utf8_high)
++			    continue;
++			cp = 0x10000 + ((utf8_high - 0xD800) << 10) + (cp - 0xDC00);
++		    }
++		    utf8_high = 0;
++		    utf8_len = 0;
++		    if (cp < 0x800) {
++			utf8_pend[utf8_len++] = (int) (0xC0 | (cp >> 6));
++		    } else if (cp < 0x10000) {
++			utf8_pend[utf8_len++] = (int) (0xE0 | (cp >> 12));
++			utf8_pend[utf8_len++] = (int) (0x80 | ((cp >> 6) & 0x3F));
++		    } else {
++			utf8_pend[utf8_len++] = (int) (0xF0 | (cp >> 18));
++			utf8_pend[utf8_len++] = (int) (0x80 | ((cp >> 12) & 0x3F));
++			utf8_pend[utf8_len++] = (int) (0x80 | ((cp >> 6) & 0x3F));
++		    }
++		    utf8_pend[utf8_len++] = (int) (0x80 | (cp & 0x3F));
++		    *buf = utf8_pend[0];
++		    utf8_pos = 1;
++		    break;
++		}
++#endif
+ 		/*
+ 		 * There are 24 virtual function-keys, and typically
+ 		 * 12 function-keys on a keyboard.  Use the shift-modifier
+--- a/ncurses/widechar/widechars.c
++++ b/ncurses/widechar/widechars.c
+@@ -97,20 +97,10 @@
+     wchar_t temp;
+ 
+     if (s != NULL && n != 0) {
++	/* _nc_mbtowc() returns the bytes used, not a character count */
+ 	count = _nc_mbtowc(&temp, s, n);
+-	if (count == 1) {
+-	    int check = WideCharToMultiByte(CP_UTF8,
+-					    0,
+-					    &temp,
+-					    1,
+-					    NULL,
+-					    0,	/* compute length only */
+-					    NULL,
+-					    NULL);
+-	    TR(TRACE_BITS, ("\tcheck ->%d\n", check));
+-	    if (check > 0 && (size_t) check <= n) {
+-		result = check;
+-	    }
++	if (count > 0 && (size_t) count <= n) {
++	    result = count;
+ 	}
+     } else {
+ 	result = 0;
+--- a/ncurses/win32con/win32_driver.c
++++ b/ncurses/win32con/win32_driver.c
+@@ -87,8 +87,13 @@
+     if (ch & A_BOLD)
+ 	res |= FOREGROUND_INTENSITY;
+ 
+-    if (ch & A_DIM)
+-	res |= BACKGROUND_INTENSITY;
++    /* dim lowers the foreground: bright -> normal, light gray -> dark gray */
++    if ((ch & A_DIM) && !(ch & A_BOLD)) {
++	if (res & FOREGROUND_INTENSITY)
++	    res &= ~FOREGROUND_INTENSITY;
++	else if ((res & 7) == 7)
++	    res = (res & ~7) | FOREGROUND_INTENSITY;
++    }
+ 
+     return res;
+ }
+@@ -159,7 +164,6 @@
+ 	    int y, int x, cchar_t *str, int limit)
+ {
+     int actual = 0;
+-    MakeArray(ci, CHAR_INFO, limit);
+     COORD loc, siz;
+     SMALL_RECT rec;
+     int i;
+@@ -169,39 +173,71 @@
+     AssertTCB();
+     SetSP();
+ 
+-    for (i = actual = 0; i < limit; i++) {
+-	ch = str[i];
+-	if (isWidecExt(ch))
+-	    continue;
+-	ci[actual].CharInfoChar = CharOf(ch);
+-	ci[actual].Attributes = MapAttr(WINCONSOLE.SBI.wAttributes,
+-					AttrOf(ch));
+-	if (AttrOf(ch) & A_ALTCHARSET) {
+-	    if (_nc_wacs) {
+-		int which = CharOf(ch);
+-		if (which > 0
+-		    && which < ACS_LEN
+-		    && CharOf(_nc_wacs[which]) != 0) {
+-		    ci[actual].CharInfoChar = CharOf(_nc_wacs[which]);
++    /*
++     * The console stores a double-width character as two cells flagged
++     * leading/trailing byte.  Never start or end a write inside one, and
++     * emit both halves so the columns after it stay put.
++     */
++    if (limit > 0 && x > 0 && isWidecExt(str[0])) {
++	--str;
++	--x;
++	++limit;
++    }
++    if (limit > 0 && x + limit < screen_columns(sp) && isWidecExt(str[limit]))
++	++limit;
++
++    {
++	MakeArray(ci, CHAR_INFO, limit);
++
++	for (i = actual = 0; i < limit; i++) {
++	    ch = str[i];
++	    if (isWidecExt(ch)) {
++		if (actual > 0
++		    && (ci[actual - 1].Attributes & COMMON_LVB_LEADING_BYTE)) {
++		    ci[actual] = ci[actual - 1];
++		    ci[actual].Attributes = (WORD)
++			((ci[actual].Attributes & ~COMMON_LVB_LEADING_BYTE)
++			 | COMMON_LVB_TRAILING_BYTE);
+ 		} else {
+ 		    ci[actual].CharInfoChar = ' ';
++		    ci[actual].Attributes = MapAttr(WINCONSOLE.SBI.wAttributes,
++						    AttrOf(ch));
+ 		}
++		++actual;
++		continue;
+ 	    }
++	    ci[actual].CharInfoChar = CharOf(ch);
++	    ci[actual].Attributes = MapAttr(WINCONSOLE.SBI.wAttributes,
++					    AttrOf(ch));
++	    if (AttrOf(ch) & A_ALTCHARSET) {
++		if (_nc_wacs) {
++		    int which = CharOf(ch);
++		    if (which > 0
++			&& which < ACS_LEN
++			&& CharOf(_nc_wacs[which]) != 0) {
++			ci[actual].CharInfoChar = CharOf(_nc_wacs[which]);
++		    } else {
++			ci[actual].CharInfoChar = ' ';
++		    }
++		}
++	    }
++	    if (i + 1 < limit && isWidecExt(str[i + 1]))
++		ci[actual].Attributes |= COMMON_LVB_LEADING_BYTE;
++	    ++actual;
+ 	}
+-	++actual;
+-    }
+ 
+-    loc.X = (SHORT) 0;
+-    loc.Y = (SHORT) 0;
+-    siz.X = (SHORT) actual;
+-    siz.Y = 1;
+-
+-    rec.Left = (SHORT) x;
+-    rec.Top = (SHORT) (y + AdjustY());
+-    rec.Right = (SHORT) (x + limit - 1);
+-    rec.Bottom = rec.Top;
++	loc.X = (SHORT) 0;
++	loc.Y = (SHORT) 0;
++	siz.X = (SHORT) actual;
++	siz.Y = 1;
++
++	rec.Left = (SHORT) x;
++	rec.Top = (SHORT) (y + AdjustY());
++	rec.Right = (SHORT) (x + actual - 1);
++	rec.Bottom = rec.Top;
+ 
+-    return write_screen(WINCONSOLE.hdl, ci, siz, loc, &rec);
++	return write_screen(WINCONSOLE.hdl, ci, siz, loc, &rec);
++    }
+ }
+ #define con_write(tcb, y, x, str, n) con_write16(tcb, y, x, str, n)
+ #else
diff --git a/scripts/release_windows.sh b/scripts/release_windows.sh
new file mode 100755
index 0000000..b68b5ba
--- /dev/null
+++ b/scripts/release_windows.sh
@@ -0,0 +1,65 @@
+#!/usr/bin/env bash
+# Publish dist/cst-agent-VERSION-windows-x86_64.zip (+ .sha256) to the Gitea
+# release vVERSION, creating the release (and its tag at HEAD) when missing.
+#   GITEA_TOKEN=... scripts/release_windows.sh [--build]
+# --build runs scripts/bootstrap_windows.sh first. The token is only read from
+# the environment and handed to curl on stdin: it never appears in argv, on
+# disk or in the output. Assets of the same name are replaced.
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+SERVER="${CST_GITEA:-https://git.whcself.xyz}"
+REPO="${CST_REPO:-WHC/CST-agent}"
+API="$SERVER/api/v1/repos/$REPO"
+
+[[ -n "${GITEA_TOKEN:-}" ]] || {
+  echo "set GITEA_TOKEN (a Gitea token with write:repository)" >&2
+  exit 1
+}
+command -v python3 >/dev/null || { echo "missing python3" >&2; exit 1; }
+cd "$ROOT"
+[[ "${1:-}" == --build ]] && scripts/bootstrap_windows.sh "$ROOT"
+
+ver="$(sed -n 's/^#define CST_VERSION_\(MAJOR\|MINOR\|PATCH\) \([0-9]*\)$/\2/p' include/cst_version.h | paste -sd.)"
+tag="v$ver"
+zip="dist/cst-agent-$ver-windows-x86_64.zip"
+for f in "$zip" "$zip.sha256"; do
+  [[ -f "$f" ]] || { echo "missing $f (scripts/package_windows.sh, or --build)" >&2; exit 1; }
+done
+
+api() { # METHOD PATH [curl args...]
+  local m="$1" p="$2"
+  shift 2
+  printf 'Authorization: token %s\n' "$GITEA_TOKEN" |
+    curl -fsS -X "$m" -H @- "$API$p" "$@"
+}
+json() { # CODE [ARGS...]: d = the JSON on stdin, ARGS in sys.argv[1:]
+  local code="$1"
+  shift
+  python3 -c "import json,sys; d=json.load(sys.stdin); $code" "$@"
+}
+
+if rel="$(api GET "/releases/tags/$tag" 2>/dev/null)"; then
+  echo "==> release $tag exists"
+else
+  head="$(git rev-parse HEAD)"
+  if ! git branch -r --contains "$head" 2>/dev/null | grep -q .; then
+    echo "HEAD $head is not on any remote branch; push it first" >&2
+    exit 1
+  fi
+  echo "==> creating release $tag at $head"
+  body="$(python3 -c 'import json,sys; print(json.dumps({"tag_name": sys.argv[1], "target_commitish": sys.argv[2], "name": "CST-Agent " + sys.argv[1], "body": "Windows x86_64: unzip, or install with scripts/install_windows.ps1"}))' "$tag" "$head")"
+  rel="$(api POST /releases -H 'Content-Type: application/json' -d "$body")"
+fi
+id="$(json 'print(d["id"])' <<<"$rel")"
+
+for f in "$zip" "$zip.sha256"; do
+  name="$(basename "$f")"
+  old="$(json "print(' '.join(str(a['id']) for a in d.get('assets') or [] if a['name'] == sys.argv[1]))" "$name" <<<"$rel")"
+  for aid in $old; do
+    echo "==> replacing $name"
+    api DELETE "/releases/$id/assets/$aid" >/dev/null
+  done
+  echo "==> upload $name"
+  api POST "/releases/$id/assets?name=$name" -F "attachment=@$f" >/dev/null
+done
+echo "$SERVER/$REPO/releases/tag/$tag"
diff --git a/scripts/run_windows.bat b/scripts/run_windows.bat
deleted file mode 100755
index e0c8eff..0000000
--- a/scripts/run_windows.bat
+++ /dev/null
@@ -1,27 +0,0 @@
-@echo off
-REM Run ON Windows after copying dist/windows-x86_64 (or a full git checkout + MSYS2 build).
-REM This script only documents env + launch; prefer bootstrap_windows.sh on Linux for cross-build.
-
-setlocal
-if "%OPENAI_API_KEY%"=="" if "%CST_API_KEY%"=="" (
-  echo Set OPENAI_API_KEY or CST_API_KEY first. See docs\env_openai.md
-  echo Example:
-  echo   set OPENAI_API_KEY=sk-...
-  echo   set OPENAI_BASE_URL=https://api.openai.com/v1
-  echo   set OPENAI_MODEL=gpt-4.1-mini
-  exit /b 1
-)
-
-if not exist cst-agent.exe (
-  echo cst-agent.exe not found in %CD%
-  echo Copy dist\windows-x86_64\* here, or build with MSYS2/MinGW.
-  exit /b 1
-)
-
-if not exist busybox.exe (
-  echo WARNING: busybox.exe missing — run_shell may fail. Place busybox.exe beside cst-agent.exe
-)
-
-echo Launching CST-Agent...
-cst-agent.exe --workspace .
-endlocal
diff --git a/scripts/win_test.sh b/scripts/win_test.sh
new file mode 100755
index 0000000..42b8a3c
--- /dev/null
+++ b/scripts/win_test.sh
@@ -0,0 +1,65 @@
+#!/usr/bin/env bash
+# Run the cross-built Windows tests inside the test VMs (scripts/winvm/vm.sh).
+#
+#   scripts/win_test.sh [-b BUILD_DIR] [-v "en zh"] [-u "Administrator tester 测试"] [-f FILTER]
+#
+# BUILD_DIR (default build-win) must contain test_*.exe from the MinGW build;
+# busybox.exe is taken from third_party/busybox/. VMs that are not running are
+# started and stopped again afterwards. Exit status is the number of failed
+# variant/user runs.
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+VM="$ROOT/scripts/winvm/vm.sh"
+BUILD="$ROOT/build-win"
+VARIANTS="en zh"
+USERS_LIST="Administrator tester 测试"
+FILTER="*"
+while getopts "b:v:u:f:" o; do
+  case "$o" in
+  b) BUILD="$(cd "$OPTARG" && pwd)" ;;
+  v) VARIANTS="$OPTARG" ;;
+  u) USERS_LIST="$OPTARG" ;;
+  f) FILTER="$OPTARG" ;;
+  *) sed -n '2,8p' "$0"; exit 2 ;;
+  esac
+done
+
+shopt -s nullglob
+exes=("$BUILD"/test_*.exe)
+[[ ${#exes[@]} -gt 0 ]] || { echo "no test_*.exe in $BUILD" >&2; exit 1; }
+
+stage="$(mktemp -d)"
+trap 'rm -rf "$stage"' EXIT
+mkdir -p "$stage/bundle/bin" "$stage/bundle/data/tests"
+cp "${exes[@]}" "$stage/bundle/bin/"
+for f in "$BUILD"/*.dll "$ROOT/third_party/busybox/busybox.exe"; do
+  [[ -f "$f" ]] && cp "$f" "$stage/bundle/bin/"
+done
+cp -r "$ROOT/tests/fixtures" "$stage/bundle/data/tests/"
+cp "$ROOT/scripts/winvm/run_tests.ps1" "$stage/bundle/"
+tar -C "$stage" -cf "$stage/bundle.tar" bundle
+
+total_fail=0
+summary=()
+for v in $VARIANTS; do
+  started=0
+  if [[ "$("$VM" status "$v")" != running ]]; then
+    "$VM" start "$v"
+    started=1
+  fi
+  "$VM" ssh "$v" 'Remove-Item -Recurse -Force C:\cst-test\bundle -ErrorAction SilentlyContinue; New-Item -ItemType Directory -Force C:\cst-test | Out-Null' >/dev/null
+  "$VM" put "$v" "$stage/bundle.tar" "C:/cst-test/bundle.tar"
+  "$VM" ssh "$v" 'tar -xf C:\cst-test\bundle.tar -C C:\cst-test; Remove-Item C:\cst-test\bundle.tar' >/dev/null
+  for u in $USERS_LIST; do
+    echo "===== $v / $u"
+    rc=0
+    "$VM" ps "$v" "$u" "$stage/bundle/run_tests.ps1" -Bundle 'C:\cst-test\bundle' -Filter "'$FILTER'" || rc=$?
+    summary+=("$v/$u: $([[ $rc == 0 ]] && echo ok || echo FAIL)")
+    [[ $rc == 0 ]] || total_fail=$((total_fail + 1))
+  done
+  [[ $started == 1 ]] && "$VM" stop "$v"
+done
+
+echo
+printf '%s\n' "${summary[@]}"
+exit "$total_fail"
diff --git a/scripts/windows/cst-agent-update.cmd b/scripts/windows/cst-agent-update.cmd
new file mode 100644
index 0000000..f8f84bd
--- /dev/null
+++ b/scripts/windows/cst-agent-update.cmd
@@ -0,0 +1,4 @@
+@echo off
+rem Update CST-Agent in this folder from the latest release.
+rem   cst-agent-update [-Version 0.6.0]
+powershell -NoProfile -ExecutionPolicy Bypass -File "%~dp0install_windows.ps1" -Prefix "%~dp0." %*
diff --git a/scripts/winvm/autounattend.xml.in b/scripts/winvm/autounattend.xml.in
new file mode 100644
index 0000000..8dead76
--- /dev/null
+++ b/scripts/winvm/autounattend.xml.in
@@ -0,0 +1,98 @@
+<?xml version="1.0" encoding="utf-8"?>
+<unattend xmlns="urn:schemas-microsoft-com:unattend" xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State">
+  <settings pass="windowsPE">
+    <component name="Microsoft-Windows-International-Core-WinPE" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
+      <SetupUILanguage>
+        <UILanguage>en-US</UILanguage>
+      </SetupUILanguage>
+      <InputLocale>en-US</InputLocale>
+      <SystemLocale>en-US</SystemLocale>
+      <UILanguage>en-US</UILanguage>
+      <UserLocale>en-US</UserLocale>
+    </component>
+    <component name="Microsoft-Windows-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
+      <DiskConfiguration>
+        <Disk wcm:action="add">
+          <DiskID>0</DiskID>
+          <WillWipeDisk>true</WillWipeDisk>
+          <CreatePartitions>
+            <CreatePartition wcm:action="add">
+              <Order>1</Order>
+              <Type>Primary</Type>
+              <Extend>true</Extend>
+            </CreatePartition>
+          </CreatePartitions>
+          <ModifyPartitions>
+            <ModifyPartition wcm:action="add">
+              <Order>1</Order>
+              <PartitionID>1</PartitionID>
+              <Active>true</Active>
+              <Format>NTFS</Format>
+              <Label>Windows</Label>
+              <Letter>C</Letter>
+            </ModifyPartition>
+          </ModifyPartitions>
+        </Disk>
+      </DiskConfiguration>
+      <ImageInstall>
+        <OSImage>
+          <InstallFrom>
+            <MetaData wcm:action="add">
+              <Key>/IMAGE/NAME</Key>
+              <Value>@IMAGE_NAME@</Value>
+            </MetaData>
+          </InstallFrom>
+          <InstallTo>
+            <DiskID>0</DiskID>
+            <PartitionID>1</PartitionID>
+          </InstallTo>
+        </OSImage>
+      </ImageInstall>
+      <UserData>
+        <AcceptEula>true</AcceptEula>
+        <FullName>CST</FullName>
+        <Organization>CST</Organization>
+      </UserData>
+    </component>
+  </settings>
+  <settings pass="specialize">
+    <component name="Microsoft-Windows-Shell-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
+      <ComputerName>cst-win</ComputerName>
+      <TimeZone>China Standard Time</TimeZone>
+    </component>
+  </settings>
+  <settings pass="oobeSystem">
+    <component name="Microsoft-Windows-Shell-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
+      <OOBE>
+        <HideEULAPage>true</HideEULAPage>
+        <HideOnlineAccountScreens>true</HideOnlineAccountScreens>
+        <HideWirelessSetupInOOBE>true</HideWirelessSetupInOOBE>
+        <ProtectYourPC>3</ProtectYourPC>
+        <NetworkLocation>Work</NetworkLocation>
+      </OOBE>
+      <UserAccounts>
+        <AdministratorPassword>
+          <Value>@ADMIN_PASSWORD@</Value>
+          <PlainText>true</PlainText>
+        </AdministratorPassword>
+      </UserAccounts>
+      <AutoLogon>
+        <Enabled>true</Enabled>
+        <Username>Administrator</Username>
+        <Password>
+          <Value>@ADMIN_PASSWORD@</Value>
+          <PlainText>true</PlainText>
+        </Password>
+        <LogonCount>1</LogonCount>
+      </AutoLogon>
+      <FirstLogonCommands>
+        <SynchronousCommand wcm:action="add">
+          <Order>1</Order>
+          <CommandLine>powershell -NoProfile -ExecutionPolicy Bypass -Command "foreach ($d in Get-PSDrive -PSProvider FileSystem) { $p = Join-Path $d.Root 'setup.ps1'; if (Test-Path $p) { &amp; $p; break } }"</CommandLine>
+          <Description>Enable OpenSSH</Description>
+          <RequiresUserInput>false</RequiresUserInput>
+        </SynchronousCommand>
+      </FirstLogonCommands>
+    </component>
+  </settings>
+</unattend>
diff --git a/scripts/winvm/provision.ps1 b/scripts/winvm/provision.ps1
new file mode 100644
index 0000000..7d94151
--- /dev/null
+++ b/scripts/winvm/provision.ps1
@@ -0,0 +1,28 @@
+# Idempotent VM setup after install: test users, sshd access, console defaults.
+# Users come from C:\Windows\Temp\cst-users.txt ("name<TAB>password", UTF-8), deleted afterwards.
+$ErrorActionPreference = 'Stop'
+
+$list = 'C:\Windows\Temp\cst-users.txt'
+if (Test-Path $list) {
+    foreach ($line in Get-Content -Path $list -Encoding UTF8) {
+        $name, $pw = $line -split "`t", 2
+        if (-not $name) { continue }
+        $sec = ConvertTo-SecureString $pw -AsPlainText -Force
+        if (Get-LocalUser -Name $name -ErrorAction SilentlyContinue) {
+            Set-LocalUser -Name $name -Password $sec
+        } else {
+            New-LocalUser -Name $name -Password $sec -PasswordNeverExpires -AccountNeverExpires | Out-Null
+        }
+        foreach ($g in 'Users', 'OpenSSH Users') {
+            Add-LocalGroupMember -Group $g -Member $name -ErrorAction SilentlyContinue
+        }
+        "user ok: $name"
+    }
+    Remove-Item -Force $list
+}
+
+# the built-in rule only covers the Private profile; QEMU user networking is Public
+Set-NetFirewallRule -Name 'OpenSSH-Server-In-TCP' -Profile Any -Enabled True
+Set-SConfig -AutoLaunch $false
+New-Item -ItemType Directory -Force C:\cst-test | Out-Null
+"provision ok"
diff --git a/scripts/winvm/run_tests.ps1 b/scripts/winvm/run_tests.ps1
new file mode 100644
index 0000000..9fc42c6
--- /dev/null
+++ b/scripts/winvm/run_tests.ps1
@@ -0,0 +1,51 @@
+# Run cross-built test_*.exe inside the VM as the current user.
+#   run_tests.ps1 BUNDLE [FILTER]
+# BUNDLE holds bin\ (exes, busybox.exe) and data\ (repo-relative fixtures).
+# Each run copies data\ into a per-user work dir and uses it as the cwd.
+param([Parameter(Mandatory = $true)][string]$Bundle, [string]$Filter = '*')
+$ErrorActionPreference = 'Stop'
+[Console]::OutputEncoding = [Text.UTF8Encoding]::new($false)
+$OutputEncoding = [Console]::OutputEncoding
+
+$work = Join-Path $env:TEMP ('cst-test-' + [guid]::NewGuid().ToString('N').Substring(0, 8))
+New-Item -ItemType Directory -Force $work | Out-Null
+Copy-Item -Recurse -Force (Join-Path $Bundle 'data\*') $work
+$env:PATH = (Join-Path $Bundle 'bin') + ';' + $env:PATH
+
+$acp = [Text.Encoding]::Default.CodePage
+"== user=$env:USERNAME acp=$acp work=$work"
+$fail = 0
+$pass = 0
+foreach ($exe in Get-ChildItem (Join-Path $Bundle 'bin') -Filter "test_$Filter.exe" | Sort-Object Name) {
+    $name = $exe.BaseName
+    $out = Join-Path $work "$name.out"
+    $err = Join-Path $work "$name.err"
+    $sw = [Diagnostics.Stopwatch]::StartNew()
+    $p = Start-Process -FilePath $exe.FullName -WorkingDirectory $work -NoNewWindow -PassThru `
+        -RedirectStandardOutput $out -RedirectStandardError $err
+    $null = $p.Handle
+    if (-not $p.WaitForExit(300000)) {
+        & taskkill.exe /T /F /PID $p.Id | Out-Null
+        $code = 'timeout'
+    } else {
+        $p.WaitForExit()
+        $code = $p.ExitCode
+    }
+    $secs = [math]::Round($sw.Elapsed.TotalSeconds, 1)
+    if ($code -eq 0) {
+        $pass++
+        "PASS $name (${secs}s)"
+    } else {
+        $fail++
+        "FAIL $name (exit $code, ${secs}s)"
+        foreach ($f in $out, $err) {
+            if (Test-Path $f) {
+                Get-Content -Path $f -Encoding UTF8 -Tail 25 | ForEach-Object { "    $_" }
+            }
+        }
+    }
+}
+"== $pass passed, $fail failed"
+Set-Location $env:TEMP
+Remove-Item -Recurse -Force $work -ErrorAction SilentlyContinue
+exit $fail
diff --git a/scripts/winvm/setup.ps1 b/scripts/winvm/setup.ps1
new file mode 100644
index 0000000..e7e42d9
--- /dev/null
+++ b/scripts/winvm/setup.ps1
@@ -0,0 +1,28 @@
+Start-Transcript -Path C:\setup.log -Append
+$ErrorActionPreference = 'Continue'
+
+if (-not (Get-Service sshd -ErrorAction SilentlyContinue)) {
+    Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0
+}
+Set-Service -Name sshd -StartupType Automatic
+Start-Service sshd
+
+$keys = 'C:\ProgramData\ssh\administrators_authorized_keys'
+Get-Content (Join-Path $PSScriptRoot 'vm_key.pub') | Set-Content -Path $keys -Encoding ascii
+icacls $keys /inheritance:r /grant 'Administrators:F' /grant 'SYSTEM:F'
+
+New-ItemProperty -Path HKLM:\SOFTWARE\OpenSSH -Name DefaultShell -PropertyType String -Force `
+    -Value 'C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe'
+
+if (Get-NetFirewallRule -Name 'OpenSSH-Server-In-TCP' -ErrorAction SilentlyContinue) {
+    # the built-in rule only covers the Private profile; QEMU user networking is Public
+    Set-NetFirewallRule -Name 'OpenSSH-Server-In-TCP' -Profile Any -Enabled True
+} else {
+    New-NetFirewallRule -Name 'OpenSSH-Server-In-TCP' -DisplayName 'OpenSSH Server (sshd)' `
+        -Enabled True -Direction Inbound -Protocol TCP -Action Allow -LocalPort 22 -Profile Any
+}
+
+powercfg /change monitor-timeout-ac 0
+powercfg /change standby-timeout-ac 0
+New-Item -Path C:\setup.done -ItemType File -Force
+Stop-Transcript
diff --git a/scripts/winvm/type.py b/scripts/winvm/type.py
new file mode 100644
index 0000000..f2fe1f8
--- /dev/null
+++ b/scripts/winvm/type.py
@@ -0,0 +1,66 @@
+#!/usr/bin/env python3
+"""Type text into the VM console via QMP.
+
+  type.py QMP_SOCKET TEXT     (\\n = Enter)
+  type.py QMP_SOCKET @FILE    the file's first line, then Enter (secrets stay
+                              off the command line)
+  type.py QMP_SOCKET --cad    Ctrl+Alt+Del
+"""
+import json
+import os
+import socket
+import sys
+import time
+
+SHIFTED = {
+    '!': '1', '@': '2', '#': '3', '$': '4', '%': '5', '^': '6', '&': '7',
+    '*': '8', '(': '9', ')': '0', '_': 'minus', '+': 'equal', '{': 'bracket_left',
+    '}': 'bracket_right', '|': 'backslash', ':': 'semicolon', '"': 'apostrophe',
+    '<': 'comma', '>': 'dot', '?': 'slash', '~': 'grave_accent',
+}
+PLAIN = {
+    ' ': 'spc', '\n': 'ret', '\t': 'tab', '-': 'minus', '=': 'equal',
+    '[': 'bracket_left', ']': 'bracket_right', '\\': 'backslash', ';': 'semicolon',
+    "'": 'apostrophe', ',': 'comma', '.': 'dot', '/': 'slash', '`': 'grave_accent',
+}
+
+
+def keys_for(ch):
+    if ch.isascii() and ch.isalpha():
+        return (['shift'] if ch.isupper() else []) + [ch.lower()]
+    if ch.isdigit():
+        return [ch]
+    if ch in PLAIN:
+        return [PLAIN[ch]]
+    if ch in SHIFTED:
+        return ['shift', SHIFTED[ch]]
+    raise SystemExit(f'unsupported char {ch!r}')
+
+
+def main():
+    arg = sys.argv[2]
+    if arg == '--cad':
+        combos = [['ctrl', 'alt', 'delete']]
+    else:
+        if arg.startswith('@'):
+            with open(arg[1:], encoding='utf-8') as fp:
+                text = fp.readline().rstrip('\r\n') + '\n'
+        else:
+            text = arg.encode().decode('unicode_escape')
+        combos = [keys_for(ch) for ch in text]
+    s = socket.socket(socket.AF_UNIX)
+    s.connect(sys.argv[1])
+    f = s.makefile('rw')
+    f.readline()
+    f.write(json.dumps({'execute': 'qmp_capabilities'}) + '\n')
+    f.flush()
+    f.readline()
+    for combo in combos:
+        keys = [{'type': 'qcode', 'data': k} for k in combo]
+        f.write(json.dumps({'execute': 'send-key', 'arguments': {'keys': keys}}) + '\n')
+        f.flush()
+        f.readline()
+        time.sleep(0.03)
+
+
+main()
diff --git a/scripts/winvm/vm.sh b/scripts/winvm/vm.sh
new file mode 100755
index 0000000..d8ee115
--- /dev/null
+++ b/scripts/winvm/vm.sh
@@ -0,0 +1,288 @@
+#!/usr/bin/env bash
+# Headless Windows Server 2025 Core test VMs (QEMU/KVM).
+#
+#   vm.sh create                 download the evaluation ISO, install base.qcow2
+#   vm.sh variants               en.qcow2 / zh.qcow2 overlays on top of base.qcow2
+#                                (zh: zh-CN system locale, ANSI code page 936)
+#   vm.sh start|stop|status|wait VARIANT
+#   vm.sh ssh VARIANT [USER] [command...]   USER: Administrator (default), tester, 测试
+#   vm.sh put VARIANT SRC... DEST           scp as Administrator
+#   vm.sh ps VARIANT [USER] FILE.ps1 [args...]   run a script (uploaded with a UTF-8 BOM)
+#   vm.sh shot VARIANT [out.png]            console screenshot
+#   vm.sh type VARIANT TEXT                 type into the console (\n = Enter)
+#   vm.sh login VARIANT                     unlock the console as Administrator
+#
+# State (ISO, disks, keys, passwords) lives in $CST_WINVM_DIR, default ~/winvm.
+# Keys and passwords are created there with mode 0600 and never printed.
+set -euo pipefail
+
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+D="${CST_WINVM_DIR:-$HOME/winvm}"
+ISO_URL="https://aka.ms/WinServ2025iso-enus"
+IMAGE_NAME="Windows Server 2025 SERVERSTANDARDCORE"
+USERS=(tester 测试)
+
+if ! command -v qemu-system-x86_64 >/dev/null || ! command -v sshpass >/dev/null ||
+  ! command -v socat >/dev/null || ! command -v xorriso >/dev/null; then
+  if command -v nix-shell >/dev/null && [[ -z "${CST_WINVM_NIX:-}" ]]; then
+    export CST_WINVM_NIX=1
+    exec nix-shell -p qemu sshpass socat xorriso imagemagick python3 \
+      --run "$(printf '%q ' "$0" "$@")"
+  fi
+  echo "need qemu-system-x86_64, sshpass, socat, xorriso" >&2
+  exit 1
+fi
+
+die() { echo "vm.sh: $*" >&2; exit 1; }
+
+port_of() {
+  case "$1" in
+  base) echo 2221 ;;
+  en) echo 2222 ;;
+  zh) echo 2223 ;;
+  *) die "unknown variant '$1' (base, en, zh)" ;;
+  esac
+}
+
+pw_file() {
+  case "$1" in
+  Administrator) echo "$D/admin-password" ;;
+  tester) echo "$D/tester-password" ;;
+  测试) echo "$D/ceshi-password" ;;
+  *) die "unknown user '$1'" ;;
+  esac
+}
+
+new_password() { # prefix -> file, mixed classes for Windows complexity rules
+  local f="$2"
+  [[ -s "$f" ]] && return 0
+  (umask 077; printf '%s%s9a' "$1" "$(head -c 256 /dev/urandom | tr -dc 'A-Za-z0-9' | head -c 16)" >"$f")
+}
+
+running() {
+  local pid
+  pid="$(cat "$D/$1.pid" 2>/dev/null)" || return 1
+  [[ -n "$pid" ]] && kill -0 "$pid" 2>/dev/null
+}
+
+ssh_opts() {
+  echo -p "$(port_of "$1")" -o UserKnownHostsFile="$D/known_hosts" \
+    -o StrictHostKeyChecking=accept-new -o LogLevel=ERROR -o ConnectTimeout=10
+}
+
+vm_ssh() { # variant user command...
+  local v="$1" u="$2"
+  shift 2
+  # shellcheck disable=SC2046
+  if [[ "$u" == Administrator ]]; then
+    ssh -i "$D/vm_key" -o BatchMode=yes $(ssh_opts "$v") "Administrator@127.0.0.1" "$@"
+  else
+    SSHPASS="$(cat "$(pw_file "$u")")" sshpass -e ssh -o PubkeyAuthentication=no \
+      -o PreferredAuthentications=password $(ssh_opts "$v") "$u@127.0.0.1" "$@"
+  fi
+}
+
+vm_put() { # variant src... dest
+  local v="$1"
+  shift
+  local dest="${!#}"
+  local srcs=("${@:1:$#-1}")
+  # shellcheck disable=SC2046
+  scp -q -r -i "$D/vm_key" -o BatchMode=yes $(ssh_opts "$v" | sed 's/^-p/-P/') \
+    "${srcs[@]}" "Administrator@127.0.0.1:$dest"
+}
+
+qemu_start() { # variant disk [extra args...]
+  local v="$1" disk="$2"
+  shift 2
+  running "$v" && return 0
+  [[ -f "$disk" ]] || die "missing $disk"
+  qemu-system-x86_64 \
+    -name "cst-win-$v" -machine q35,accel=kvm \
+    -cpu host,hv_relaxed,hv_spinlocks=0x1fff,hv_vapic,hv_time \
+    -smp 4 -m 6G -rtc base=localtime \
+    -device ahci,id=ahci \
+    -drive file="$disk",if=none,id=d0,cache=writeback,discard=unmap \
+    -device ide-hd,drive=d0,bus=ahci.0 \
+    -netdev user,id=n0,hostfwd=tcp:127.0.0.1:"$(port_of "$v")"-:22 \
+    -device e1000e,netdev=n0 \
+    -device qemu-xhci,id=xhci -device usb-tablet,bus=xhci.0 \
+    -display none -qmp unix:"$D/$v.qmp",server,nowait \
+    -pidfile "$D/$v.pid" -daemonize "$@"
+}
+
+disk_of() {
+  case "$1" in
+  base) echo "$D/base.qcow2" ;;
+  *) echo "$D/$1.qcow2" ;;
+  esac
+}
+
+vm_wait() { # variant [timeout_s]
+  local v="$1" t="${2:-900}" i
+  for ((i = 0; i < t; i += 5)); do
+    if vm_ssh "$v" Administrator 'Test-Path C:\setup.done' 2>/dev/null | grep -q True; then
+      return 0
+    fi
+    running "$v" || die "$v is not running"
+    sleep 5
+  done
+  die "$v: no SSH after ${t}s"
+}
+
+vm_stop() {
+  local v="$1" i
+  running "$v" || return 0
+  vm_ssh "$v" Administrator 'Stop-Computer -Force' >/dev/null 2>&1 || true
+  for ((i = 0; i < 120; i++)); do
+    running "$v" || { rm -f "$D/$v.pid" "$D/$v.qmp"; return 0; }
+    sleep 1
+  done
+  printf '%s\n' '{"execute":"qmp_capabilities"}' '{"execute":"quit"}' |
+    socat - UNIX-CONNECT:"$D/$v.qmp" >/dev/null || true
+  rm -f "$D/$v.pid" "$D/$v.qmp"
+}
+
+with_bom() { # file -> temp copy with a UTF-8 BOM (Windows PowerShell 5.1 reads ANSI otherwise)
+  local out
+  out="$(mktemp --suffix=.ps1)"
+  printf '\xef\xbb\xbf' >"$out"
+  sed '1s/^\xef\xbb\xbf//' "$1" >>"$out"
+  echo "$out"
+}
+
+vm_ps() { # variant user file args...
+  local v="$1" u="$2" f="$3"
+  shift 3
+  local tmp name
+  tmp="$(with_bom "$f")"
+  name="cst-$(basename "$f" .ps1)-$$.ps1"
+  vm_put "$v" "$tmp" "C:/Windows/Temp/$name"
+  rm -f "$tmp"
+  vm_ssh "$v" Administrator "icacls C:\\Windows\\Temp\\$name /grant 'Users:RX' | Out-Null" >/dev/null
+  local rc=0
+  vm_ssh "$v" "$u" "powershell -NoProfile -ExecutionPolicy Bypass -File C:\\Windows\\Temp\\$name $*" || rc=$?
+  vm_ssh "$v" Administrator "Remove-Item -Force C:\\Windows\\Temp\\$name" >/dev/null 2>&1 || true
+  return $rc
+}
+
+provision() { # variant: users, sshd, console; idempotent
+  local v="$1" u tmp
+  tmp="$(mktemp)"
+  chmod 600 "$tmp"
+  for u in "${USERS[@]}"; do
+    new_password "Tst!" "$(pw_file "$u")"
+    printf '%s\t%s\n' "$u" "$(cat "$(pw_file "$u")")" >>"$tmp"
+  done
+  vm_put "$v" "$tmp" "C:/Windows/Temp/cst-users.txt"
+  rm -f "$tmp"
+  vm_ps "$v" Administrator "$HERE/provision.ps1"
+}
+
+cmd_create() {
+  mkdir -p "$D"
+  chmod 700 "$D"
+  [[ -f "$D/base.qcow2" ]] && die "$D/base.qcow2 exists"
+  if [[ ! -s "$D/server2025.iso" ]]; then
+    echo "==> downloading the Windows Server 2025 evaluation ISO (~8 GB)"
+    curl -fL -C - -o "$D/server2025.iso" "$ISO_URL"
+  fi
+  [[ -f "$D/vm_key" ]] || ssh-keygen -q -t ed25519 -N "" -C cst-winvm -f "$D/vm_key"
+  new_password "Cst!" "$D/admin-password"
+
+  local u
+  u="$(mktemp -d)"
+  chmod 700 "$u"
+  cp "$HERE/setup.ps1" "$D/vm_key.pub" "$u/"
+  (umask 077
+    sed -e "s|@IMAGE_NAME@|$IMAGE_NAME|" -e "s|@ADMIN_PASSWORD@|$(cat "$D/admin-password")|g" \
+      "$HERE/autounattend.xml.in" >"$u/autounattend.xml"
+    xorriso -as mkisofs -quiet -J -r -V UNATTEND -o "$D/unattend.iso" "$u/" 2>/dev/null)
+  rm -rf "$u"
+
+  qemu-img create -q -f qcow2 "$D/base.qcow2" 60G
+  echo "==> unattended install (20-30 minutes)"
+  qemu_start base "$D/base.qcow2" \
+    -drive file="$D/server2025.iso",media=cdrom,if=none,id=cd0,readonly=on \
+    -device ide-cd,drive=cd0,bus=ahci.1 \
+    -drive file="$D/unattend.iso",media=cdrom,if=none,id=cd1,readonly=on \
+    -device ide-cd,drive=cd1,bus=ahci.2 \
+    -boot order=c,once=d
+  vm_wait base 3600
+  provision base
+  vm_stop base
+  echo "OK: $D/base.qcow2; next: vm.sh variants"
+}
+
+cmd_variants() {
+  [[ -f "$D/base.qcow2" ]] || die "no base.qcow2; run vm.sh create"
+  running base && die "stop the base VM first"
+  local v
+  for v in en zh; do
+    running "$v" && vm_stop "$v"
+    rm -f "$D/$v.qcow2"
+    qemu-img create -q -f qcow2 -b "$D/base.qcow2" -F qcow2 "$D/$v.qcow2"
+  done
+  qemu_start zh "$D/zh.qcow2"
+  vm_wait zh
+  vm_ssh zh Administrator 'Set-WinSystemLocale -SystemLocale zh-CN; Set-Culture zh-CN; Set-WinHomeLocation -GeoId 45; Restart-Computer -Force' || true
+  sleep 20
+  vm_wait zh
+  echo "zh ANSI code page: $(vm_ssh zh Administrator '[Text.Encoding]::Default.CodePage')"
+  vm_stop zh
+  echo "OK: en.qcow2 zh.qcow2"
+}
+
+cmd="${1:-}"
+shift || true
+case "$cmd" in
+create) cmd_create ;;
+variants) cmd_variants ;;
+provision) provision "${1:?variant}" ;;
+start)
+  qemu_start "${1:?variant}" "$(disk_of "$1")"
+  vm_wait "$1"
+  ;;
+stop) vm_stop "${1:?variant}" ;;
+status) running "${1:?variant}" && echo running || echo stopped ;;
+wait) vm_wait "${1:?variant}" "${2:-900}" ;;
+ssh)
+  v="${1:?variant}"
+  shift
+  u=Administrator
+  if [[ $# -gt 0 ]] && [[ "$1" == Administrator || "$1" == tester || "$1" == 测试 ]]; then
+    u="$1"
+    shift
+  fi
+  vm_ssh "$v" "$u" "$@"
+  ;;
+put) vm_put "$@" ;;
+ps)
+  v="${1:?variant}"
+  shift
+  u=Administrator
+  if [[ "$1" == Administrator || "$1" == tester || "$1" == 测试 ]]; then
+    u="$1"
+    shift
+  fi
+  vm_ps "$v" "$u" "$@"
+  ;;
+shot)
+  v="${1:?variant}"
+  out="${2:-$D/$v.png}"
+  printf '%s\n' '{"execute":"qmp_capabilities"}' \
+    '{"execute":"screendump","arguments":{"filename":"'"$D/$v.ppm"'"}}' |
+    socat - UNIX-CONNECT:"$D/$v.qmp" >/dev/null
+  sleep 1
+  magick "$D/$v.ppm" -resize '1024x1024>' "$out"
+  rm -f "$D/$v.ppm"
+  echo "$out"
+  ;;
+type) python3 "$HERE/type.py" "$D/${1:?variant}.qmp" "${2:?text}" ;;
+login)
+  python3 "$HERE/type.py" "$D/${1:?variant}.qmp" --cad
+  sleep 3
+  python3 "$HERE/type.py" "$D/$1.qmp" "@$D/admin-password"
+  ;;
+*) sed -n '2,15p' "$0" | sed 's/^# \{0,1\}//'; exit 2 ;;
+esac
diff --git a/shell-win.nix b/shell-win.nix
new file mode 100644
index 0000000..44d09b1
--- /dev/null
+++ b/shell-win.nix
@@ -0,0 +1,24 @@
+# Windows x86_64 cross toolchain (mingw-w64, UCRT runtime, static winpthreads).
+#   nix-shell shell-win.nix --run 'scripts/bootstrap_windows.sh'
+{ pkgs ? import <nixpkgs> { } }:
+let
+  win = pkgs.pkgsCross.ucrt64;
+in
+win.mkShell {
+  nativeBuildInputs = with pkgs; [
+    cmake
+    ninja
+    gnumake
+    git
+    perl
+    python3
+    pkg-config
+    zip
+    curl
+  ];
+  buildInputs = [ win.windows.pthreads ];
+  # mkShell exports CC/AR for the target; the build scripts call the prefixed tools directly.
+  shellHook = ''
+    export MINGW_HOST=x86_64-w64-mingw32
+  '';
+}
diff --git a/src/agent_loop.c b/src/agent_loop.c
index da8bc6c..0f41946 100644
--- a/src/agent_loop.c
+++ b/src/agent_loop.c
@@ -270,7 +270,7 @@ static void git_branch(const char *ws, char *out, size_t n) {
   for (int depth = 0; depth < 8; depth++) {
     char p[4200], line[512];
     snprintf(p, sizeof(p), "%s/.git", dir);
-    FILE *fp = fopen(p, "r");
+    FILE *fp = fopen(p, "rb");
     if (fp) {
       /* worktree / submodule: ".git" is a file "gitdir: <path>" */
       char gd[4096] = "";
@@ -286,7 +286,7 @@ static void git_branch(const char *ws, char *out, size_t n) {
         snprintf(p, sizeof(p), "%s/HEAD", gd);
       else
         snprintf(p, sizeof(p), "%s/.git/HEAD", dir);
-      fp = fopen(p, "r");
+      fp = fopen(p, "rb");
       if (fp) {
         if (fgets(line, sizeof(line), fp)) {
           line[strcspn(line, "\r\n")] = 0;
@@ -308,7 +308,13 @@ static void git_branch(const char *ws, char *out, size_t n) {
 
 static void os_label(char *out, size_t n) {
 #ifdef _WIN32
-  snprintf(out, n, "Windows");
+  char ver[64];
+  os_windows_version(ver, sizeof(ver));
+  snprintf(out, n,
+           "%s; run_shell is busybox sh (POSIX syntax and applets; write paths "
+           "as C:/dir or relative, Windows programs like git or python run "
+           "from PATH)",
+           ver);
 #else
   struct utsname u;
   if (uname(&u) == 0)
@@ -780,9 +786,14 @@ static void sandbox_escalate(turn_t *t, cst_tool_ctx_t *ctx,
     free(detail);
   }
   if (ans == CST_PERM_DENY) {
-    const char *note = "\n[cst: blocked by the sandbox (writes are limited to "
-                       "the workspace and temp dir, no network); the user did "
-                       "not allow running it outside]\n";
+    const char *note =
+        cst_sandbox_probe() == CST_SANDBOX_LOWIL
+            ? "\n[cst: blocked by the sandbox (writes are limited to the "
+              "workspace and temp dir); the user did not allow running it "
+              "outside]\n"
+            : "\n[cst: blocked by the sandbox (writes are limited to "
+              "the workspace and temp dir, no network); the user did "
+              "not allow running it outside]\n";
     cst_buf_t b = {0};
     if (tr->out)
       cst_buf_append(&b, tr->out, tr->out_len);
@@ -924,9 +935,11 @@ static void exec_begin(turn_t *t, pcall_t *pc, exec_t *x) {
       if (def->perm == CST_TP_WRITE) {
         ask = 0;
       } else if (def->perm == CST_TP_SHELL) {
-        if (cst_sandbox_probe() != CST_SANDBOX_NONE) {
+        int sb = cst_sandbox_probe();
+        if (sb != CST_SANDBOX_NONE) {
           ctx->sandbox = 1;
-          ask = 0;
+          /* the Low-IL sandbox does not stop network access */
+          ask = sb == CST_SANDBOX_LOWIL && cmd && cst_shell_uses_network(cmd);
         } else if (cmd && cst_shell_is_safe(cmd)) {
           ask = 0;
         }
@@ -1707,8 +1720,12 @@ void cst_agent_session_id(const cst_agent_t *a, char *out, size_t out_sz) {
     return;
   const char *p = a->cfg.session_path;
   const char *sl = strrchr(p, '/');
-  snprintf(out, out_sz, "%s", sl ? sl + 1 : p);
-  size_t n = strlen(out);
+  const char *base = sl ? sl + 1 : p;
+  size_t n = strlen(base);
+  if (n >= out_sz)
+    n = out_sz - 1;
+  memcpy(out, base, n);
+  out[n] = 0;
   if (n > 6 && strcmp(out + n - 6, ".jsonl") == 0)
     out[n - 6] = 0;
 }
@@ -1747,7 +1764,8 @@ void cst_agent_reload_notes(cst_agent_t *a) {
     fclose(fp);
     if (b.len && b.buf) {
       size_t clean_len = 0;
-      a->notes = cst_utf8_sanitize(b.buf, b.len, &clean_len);
+      size_t bom = cst_bom_len(b.buf, b.len);
+      a->notes = cst_utf8_sanitize(b.buf + bom, b.len - bom, &clean_len);
     }
     cst_buf_free(&b);
     return;
diff --git a/src/agent_store.c b/src/agent_store.c
index 57d4086..23628d4 100644
--- a/src/agent_store.c
+++ b/src/agent_store.c
@@ -6,7 +6,6 @@
 #include "cst_agent.h"
 #include "os_compat.h"
 
-#include <dirent.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -45,7 +44,7 @@ int cst_agent_store_ensure(const char *workspace) {
   char gi[OS_PATH_MAX];
   if (os_path_join(gi, sizeof(gi), base, ".gitignore") == 0 &&
       OS_ACCESS(gi, OS_F_OK) != 0) {
-    FILE *fp = fopen(gi, "w");
+    FILE *fp = fopen(gi, "wb");
     if (fp) {
       fputs("*\n", fp);
       fclose(fp);
@@ -97,7 +96,7 @@ int cst_agent_store_set_current(const char *workspace, const char *id) {
     return -1;
   if (os_path_join(path, sizeof(path), dir, "CURRENT") != 0)
     return -1;
-  FILE *fp = fopen(path, "w");
+  FILE *fp = fopen(path, "wb");
   if (!fp)
     return -1;
   fprintf(fp, "%s\n", id);
@@ -113,7 +112,7 @@ int cst_agent_store_get_current(const char *workspace, char *id_out,
     return -1;
   if (os_path_join(path, sizeof(path), dir, "CURRENT") != 0)
     return -1;
-  FILE *fp = fopen(path, "r");
+  FILE *fp = fopen(path, "rb");
   if (!fp)
     return -1;
   if (!fgets(id_out, (int)id_sz, fp)) {
@@ -159,7 +158,7 @@ int cst_agent_store_list(const char *workspace, char ids[][128], int max_ids) {
   char dir[OS_PATH_MAX];
   if (cst_agent_store_dir(workspace, dir, sizeof(dir)) != 0)
     return 0;
-  DIR *d = opendir(dir);
+  os_dir_t *d = os_dir_open(dir);
   if (!d)
     return 0;
   typedef struct {
@@ -168,23 +167,23 @@ int cst_agent_store_list(const char *workspace, char ids[][128], int max_ids) {
   } ent_t;
   ent_t *ents = calloc((size_t)max_ids * 4, sizeof(ent_t));
   int n = 0, cap = max_ids * 4;
-  struct dirent *de;
-  while ((de = readdir(d)) != NULL) {
-    size_t len = strlen(de->d_name);
-    if (len < 7 || strcmp(de->d_name + len - 6, ".jsonl") != 0)
+  const os_dirent_t *de;
+  while ((de = os_dir_next(d)) != NULL) {
+    size_t len = strlen(de->name);
+    if (len < 7 || strcmp(de->name + len - 6, ".jsonl") != 0)
       continue;
     if (n >= cap)
       break;
     snprintf(ents[n].id, sizeof(ents[n].id), "%.*s", (int)(len - 6),
-             de->d_name);
+             de->name);
     char full[OS_PATH_MAX];
-    if (os_path_join(full, sizeof(full), dir, de->d_name) != 0)
+    if (os_path_join(full, sizeof(full), dir, de->name) != 0)
       continue;
     struct stat st;
     ents[n].mtime = (stat(full, &st) == 0) ? st.st_mtime : 0;
     n++;
   }
-  closedir(d);
+  os_dir_close(d);
   for (int i = 0; i < n; i++) {
     for (int j = i + 1; j < n; j++) {
       if (ents[j].mtime > ents[i].mtime) {
@@ -218,7 +217,7 @@ int cst_agent_store_title_set(const char *workspace, const char *id,
     return -1;
   if (!title || !title[0])
     return remove(p) == 0 || errno == ENOENT ? 0 : -1;
-  FILE *fp = fopen(p, "w");
+  FILE *fp = fopen(p, "wb");
   if (!fp)
     return -1;
   for (const char *c = title; *c; c++)
@@ -255,7 +254,7 @@ int cst_agent_store_info(const char *workspace, const char *id,
   info->mtime = (long long)st.st_mtime;
   char tp[OS_PATH_MAX];
   if (side_path(workspace, id, ".title", tp, sizeof(tp)) == 0) {
-    FILE *tf = fopen(tp, "r");
+    FILE *tf = fopen(tp, "rb");
     if (tf) {
       if (fgets(info->title, sizeof(info->title), tf)) {
         size_t n = strlen(info->title);
@@ -265,7 +264,7 @@ int cst_agent_store_info(const char *workspace, const char *id,
       fclose(tf);
     }
   }
-  FILE *fp = fopen(p, "r");
+  FILE *fp = fopen(p, "rb");
   if (!fp)
     return 0;
   size_t cap = 1 << 16;
@@ -311,16 +310,16 @@ int cst_agent_store_delete(const char *workspace, const char *id) {
     remove(p);
   /* sub-agent transcripts live in <id>/ */
   if (side_path(workspace, id, "", p, sizeof(p)) == 0) {
-    DIR *d = opendir(p);
+    os_dir_t *d = os_dir_open(p);
     if (d) {
-      struct dirent *de;
-      while ((de = readdir(d)) != NULL) {
+      const os_dirent_t *de;
+      while ((de = os_dir_next(d)) != NULL) {
         char f[OS_PATH_MAX];
-        if (strncmp(de->d_name, "sub-", 4) == 0 &&
-            os_path_join(f, sizeof(f), p, de->d_name) == 0)
+        if (strncmp(de->name, "sub-", 4) == 0 &&
+            os_path_join(f, sizeof(f), p, de->name) == 0)
           remove(f);
       }
-      closedir(d);
+      os_dir_close(d);
       rmdir(p);
     }
   }
diff --git a/src/creds.c b/src/creds.c
index 36f4318..7a0098f 100644
--- a/src/creds.c
+++ b/src/creds.c
@@ -12,6 +12,7 @@
 
 #ifdef _WIN32
 #include <io.h>
+#include <windows.h>
 #else
 #include <fcntl.h>
 #include <termios.h>
@@ -51,7 +52,7 @@ int cst_creds_load(const char *provider, char *out, size_t out_sz) {
   char path[OS_PATH_MAX];
   if (credentials_path(path, sizeof(path)) != 0)
     return -1;
-  FILE *fp = fopen(path, "r");
+  FILE *fp = fopen(path, "rb");
   if (!fp)
     return -1;
   char want[64];
@@ -104,7 +105,9 @@ int cst_creds_save(const char *provider, const char *key) {
   size_t wl = strlen(want);
 
 #ifdef _WIN32
-  FILE *out = fopen(tmp, "w");
+  FILE *out = fopen(tmp, "wb");
+  if (out)
+    (void)os_chmod_private(tmp); /* label before the key is written */
 #else
   /* never exists world-readable, even briefly */
   int fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC, 0600);
@@ -114,7 +117,7 @@ int cst_creds_save(const char *provider, const char *key) {
 #endif
   if (!out)
     return -1;
-  FILE *in = fopen(path, "r");
+  FILE *in = fopen(path, "rb");
   if (in) {
     char line[1024];
     while (fgets(line, sizeof(line), in)) {
@@ -128,10 +131,7 @@ int cst_creds_save(const char *provider, const char *key) {
     remove(tmp);
     return -1;
   }
-#ifdef _WIN32
-  remove(path);
-#endif
-  if (rename(tmp, path) != 0) {
+  if (os_rename_replace(tmp, path) != 0) {
     remove(tmp);
     return -1;
   }
@@ -167,7 +167,13 @@ int cst_creds_prompt_console(const char *provider, char *out, size_t out_sz) {
   fprintf(stderr, "API key for %s (input hidden, saved to the config dir): ",
           provider ? provider : "?");
   fflush(stderr);
-#ifndef _WIN32
+#ifdef _WIN32
+  HANDLE hin = GetStdHandle(STD_INPUT_HANDLE);
+  DWORD old_mode = 0;
+  int tty = GetConsoleMode(hin, &old_mode) != 0;
+  if (tty)
+    SetConsoleMode(hin, old_mode & ~(DWORD)ENABLE_ECHO_INPUT);
+#else
   struct termios old, quiet;
   int tty = isatty(STDIN_FILENO) && tcgetattr(STDIN_FILENO, &old) == 0;
   if (tty) {
@@ -177,12 +183,14 @@ int cst_creds_prompt_console(const char *provider, char *out, size_t out_sz) {
   }
 #endif
   char *got = fgets(out, (int)out_sz, stdin);
-#ifndef _WIN32
   if (tty) {
+#ifdef _WIN32
+    SetConsoleMode(hin, old_mode);
+#else
     tcsetattr(STDIN_FILENO, TCSAFLUSH, &old);
+#endif
     fputc('\n', stderr);
   }
-#endif
   if (!got) {
     out[0] = 0;
     return -1;
diff --git a/src/keymap.c b/src/keymap.c
index a62294b..72833e8 100644
--- a/src/keymap.c
+++ b/src/keymap.c
@@ -1,6 +1,7 @@
 #include "cst_keymap.h"
 
 #include "cJSON.h"
+#include "cst_util.h"
 #include "os_compat.h"
 
 #include <ctype.h>
@@ -491,7 +492,7 @@ int cst_keymap_load(cst_keymap_t *km, char *err, size_t err_sz) {
   size_t n = fread(buf, 1, sizeof(buf) - 1, fp);
   fclose(fp);
   buf[n] = 0;
-  return cst_keymap_apply_json(km, buf, err, err_sz);
+  return cst_keymap_apply_json(km, buf + cst_bom_len(buf, n), err, err_sz);
 }
 
 int cst_keymap_lookup(const cst_keymap_t *km, const int *seq, int n,
diff --git a/src/llm_openai.c b/src/llm_openai.c
index 84d896d..c2028e7 100644
--- a/src/llm_openai.c
+++ b/src/llm_openai.c
@@ -805,11 +805,11 @@ int cst_llm_list_models(const char *api_base, const char *api_key,
   }
   CURL *curl = curl_easy_init();
   if (!curl) {
-      snprintf(err, err_sz, "curl init failed");
-      return -1;
-    }
-    llm_apply_ca_bundle(curl);
-    char url[1024];
+    snprintf(err, err_sz, "curl init failed");
+    return -1;
+  }
+  llm_apply_ca_bundle(curl);
+  char url[1024];
   size_t bl = strlen(api_base);
   while (bl && api_base[bl - 1] == '/')
     bl--;
diff --git a/src/main.c b/src/main.c
index b228a6e..5c59578 100644
--- a/src/main.c
+++ b/src/main.c
@@ -188,6 +188,9 @@ static int demo_ctl_impl(const char *workspace) {
 }
 
 int main(int argc, char **argv) {
+  if (os_console_init() != 0)
+    fprintf(stderr, "warning: the process code page is not UTF-8 (Windows 10 "
+                    "1903 or later is required); non-ASCII text may break\n");
   os_set_prog_path(argv[0]);
   curl_global_init(CURL_GLOBAL_DEFAULT);
 
diff --git a/src/mcp.c b/src/mcp.c
index 0f22045..cef22df 100644
--- a/src/mcp.c
+++ b/src/mcp.c
@@ -268,6 +268,7 @@ static char *slurp(const char *path, size_t max) {
   fclose(fp);
   if (!b.buf)
     cst_buf_puts(&b, "");
+  cst_strip_bom(b.buf, &b.len);
   return cst_buf_steal(&b);
 }
 
diff --git a/src/metrics.c b/src/metrics.c
index 39820c5..34fde34 100644
--- a/src/metrics.c
+++ b/src/metrics.c
@@ -47,7 +47,7 @@ cst_metrics_t *cst_metrics_open(const char *workspace, const char *session_path)
     snprintf(file, sizeof(file), "%s.jsonl", leaf);
     os_path_join(m->path, sizeof(m->path), dir, file);
   }
-  m->fp = fopen(m->path, "a");
+  m->fp = fopen(m->path, "ab");
   if (!m->fp) {
     free(m);
     return NULL;
diff --git a/src/os_compat.c b/src/os_compat.c
index a579117..b1e944e 100644
--- a/src/os_compat.c
+++ b/src/os_compat.c
@@ -10,6 +10,7 @@
 #include <stdint.h>
 #endif
 #include "os_compat.h"
+#include "os_internal.h"
 
 #include <errno.h>
 #include <stdio.h>
@@ -26,6 +27,7 @@
 #include <process.h>
 #include <windows.h>
 #else
+#include <dirent.h>
 #include <fcntl.h>
 #include <poll.h>
 #include <pthread.h>
@@ -93,26 +95,10 @@ int os_path_join(char *out, size_t out_sz, const char *a, const char *b) {
   return 0;
 }
 
+#ifndef _WIN32
 int os_realpath(const char *path, char *out, size_t out_sz) {
   if (!path || !out || out_sz < 2)
     return -1;
-#ifdef _WIN32
-  char buf[OS_PATH_MAX];
-  DWORD n = GetFullPathNameA(path, (DWORD)sizeof(buf), buf, NULL);
-  if (n == 0 || n >= sizeof(buf))
-    return -1;
-  /* Prefer forward slashes internally for sandbox compares. */
-  os_path_norm_slashes(buf);
-  if (strlen(buf) + 1 > out_sz)
-    return -1;
-  memcpy(out, buf, strlen(buf) + 1);
-  /* Lowercase drive letter for stable compares */
-  if (out[0] && out[1] == ':') {
-    if (out[0] >= 'A' && out[0] <= 'Z')
-      out[0] = (char)(out[0] - 'A' + 'a');
-  }
-  return 0;
-#else
   char *r = realpath(path, NULL);
   if (!r)
     return -1;
@@ -123,7 +109,6 @@ int os_realpath(const char *path, char *out, size_t out_sz) {
   memcpy(out, r, strlen(r) + 1);
   free(r);
   return 0;
-#endif
 }
 
 int os_path_under(const char *root, const char *path) {
@@ -132,14 +117,9 @@ int os_path_under(const char *root, const char *path) {
   size_t rl = strlen(root);
   if (strncmp(path, root, rl) != 0)
     return 0;
-  if (path[rl] == '\0')
-    return 1;
-#ifdef _WIN32
-  return path[rl] == '/' || path[rl] == '\\';
-#else
-  return path[rl] == '/';
-#endif
+  return path[rl] == '\0' || path[rl] == '/';
 }
+#endif
 
 int os_mkdir(const char *path, int mode) {
   if (!path)
@@ -172,16 +152,93 @@ int os_mkdir_p(const char *path, int mode) {
   return os_mkdir(tmp, mode);
 }
 
+#ifndef _WIN32
+struct os_dir {
+  DIR *d;
+  char path[OS_PATH_MAX];
+  os_dirent_t ent;
+};
+
+os_dir_t *os_dir_open(const char *path) {
+  if (!path)
+    return NULL;
+  os_dir_t *d = calloc(1, sizeof(*d));
+  if (!d)
+    return NULL;
+  snprintf(d->path, sizeof(d->path), "%s", path);
+  d->d = opendir(path);
+  if (!d->d) {
+    free(d);
+    return NULL;
+  }
+  return d;
+}
+
+const os_dirent_t *os_dir_next(os_dir_t *d) {
+  struct dirent *de;
+  while (d && (de = readdir(d->d)) != NULL) {
+    if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0)
+      continue;
+    d->ent.name = de->d_name;
+    d->ent.is_dir = d->ent.is_link = 0;
+#ifdef DT_DIR
+    if (de->d_type != DT_UNKNOWN) {
+      d->ent.is_dir = de->d_type == DT_DIR;
+      d->ent.is_link = de->d_type == DT_LNK;
+      return &d->ent;
+    }
+#endif
+    char p[OS_PATH_MAX];
+    struct stat st;
+    if (snprintf(p, sizeof(p), "%s/%s", d->path, de->d_name) <
+            (int)sizeof(p) &&
+        lstat(p, &st) == 0) {
+      d->ent.is_dir = S_ISDIR(st.st_mode);
+      d->ent.is_link = S_ISLNK(st.st_mode);
+    }
+    return &d->ent;
+  }
+  return NULL;
+}
+
+void os_dir_close(os_dir_t *d) {
+  if (!d)
+    return;
+  closedir(d->d);
+  free(d);
+}
+
+int os_lstat(const char *path, os_stat_t *st) {
+  struct stat s;
+  memset(st, 0, sizeof(*st));
+  if (!path || lstat(path, &s) != 0)
+    return -1;
+  st->is_dir = S_ISDIR(s.st_mode);
+  st->is_reg = S_ISREG(s.st_mode);
+  st->is_link = S_ISLNK(s.st_mode);
+  st->size = (long long)s.st_size;
+  st->mtime = (double)s.st_mtime;
+  return 0;
+}
+
+int os_rename_replace(const char *from, const char *to) {
+  return rename(from, to) == 0 ? 0 : -1;
+}
+#endif
+
 int os_config_dir(char *out, size_t out_sz) {
   if (!out || out_sz < 8)
     return -1;
 #ifdef _WIN32
-  const char *base = getenv("APPDATA");
+  const char *base = getenv("XDG_CONFIG_HOME");
+  if (!base || !os_path_is_abs(base))
+    base = getenv("APPDATA");
   if (!base || !base[0])
     base = getenv("LOCALAPPDATA");
   if (!base || !base[0])
     return -1;
-  int n = snprintf(out, out_sz, "%s\\cst-agent", base);
+  int n = snprintf(out, out_sz, "%s/cst-agent", base);
+  os_path_norm_slashes(out);
 #else
   const char *xdg = getenv("XDG_CONFIG_HOME");
   const char *home = getenv("HOME");
@@ -389,7 +446,7 @@ void os_set_run_timeout(int seconds) { g_run_timeout_s = seconds; }
 
 int os_get_run_timeout(void) { return g_run_timeout_s; }
 
-static int run_timeout_s(void) {
+int os_run_timeout_effective(void) {
   if (g_run_timeout_s > 0)
     return g_run_timeout_s;
   const char *e = getenv("CST_SHELL_TIMEOUT");
@@ -414,8 +471,8 @@ double os_now_ms(void) {
 }
 
 /* Append to capture buffer, keeping at most max_out bytes. */
-static int cap_append(char **buf, size_t *len, size_t *cap, size_t max_out,
-                      const char *data, size_t n, int *truncated) {
+int os_cap_append(char **buf, size_t *len, size_t *cap, size_t max_out,
+                  const char *data, size_t n, int *truncated) {
   if (*len >= max_out) {
     *truncated = 1;
     return 0;
@@ -440,7 +497,7 @@ static int cap_append(char **buf, size_t *len, size_t *cap, size_t max_out,
   return 0;
 }
 
-static void cap_note(char **buf, size_t *len, size_t *cap, const char *note) {
+void os_cap_note(char **buf, size_t *len, size_t *cap, const char *note) {
   size_t n = strlen(note);
   if (*len + n + 1 > *cap) {
     char *nb = realloc(*buf, *len + n + 1);
@@ -453,154 +510,7 @@ static void cap_note(char **buf, size_t *len, size_t *cap, const char *note) {
   *len += n;
 }
 
-#ifdef _WIN32
-int os_run_capture(const char *cwd, const char *const argv[], size_t max_out,
-                   os_run_result_t *r) {
-  if (!argv || !argv[0] || !r)
-    return -1;
-  if (max_out == 0)
-    max_out = 512 * 1024;
-  memset(r, 0, sizeof(*r));
-
-  char cmdline[8192];
-  size_t pos = 0;
-  cmdline[0] = 0;
-  for (int i = 0; argv[i]; i++) {
-    const char *a = argv[i];
-    int need_q = strchr(a, ' ') || strchr(a, '\t') || strchr(a, '"');
-    if (i && pos + 1 < sizeof(cmdline))
-      cmdline[pos++] = ' ';
-    if (need_q) {
-      if (pos + 1 < sizeof(cmdline))
-        cmdline[pos++] = '"';
-      for (const char *p = a; *p && pos + 2 < sizeof(cmdline); p++) {
-        if (*p == '"') {
-          cmdline[pos++] = '\\';
-          cmdline[pos++] = '"';
-        } else {
-          cmdline[pos++] = *p;
-        }
-      }
-      if (pos + 1 < sizeof(cmdline))
-        cmdline[pos++] = '"';
-    } else {
-      size_t L = strlen(a);
-      if (pos + L >= sizeof(cmdline))
-        break;
-      memcpy(cmdline + pos, a, L);
-      pos += L;
-    }
-    cmdline[pos] = 0;
-  }
-
-  SECURITY_ATTRIBUTES sa = {0};
-  sa.nLength = sizeof(sa);
-  sa.bInheritHandle = TRUE;
-  HANDLE rd = NULL, wr = NULL;
-  if (!CreatePipe(&rd, &wr, &sa, 0))
-    return -1;
-  SetHandleInformation(rd, HANDLE_FLAG_INHERIT, 0);
-
-  STARTUPINFOA si = {0};
-  si.cb = sizeof(si);
-  si.dwFlags = STARTF_USESTDHANDLES;
-  si.hStdOutput = wr;
-  si.hStdError = wr;
-  HANDLE nul = CreateFileA("NUL", GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE,
-                           &sa, OPEN_EXISTING, 0, NULL);
-  si.hStdInput = nul != INVALID_HANDLE_VALUE ? nul : GetStdHandle(STD_INPUT_HANDLE);
-  PROCESS_INFORMATION pi = {0};
-
-  char *cmd_mut = _strdup(cmdline);
-  if (!cmd_mut) {
-    CloseHandle(rd);
-    CloseHandle(wr);
-    return -1;
-  }
-  BOOL ok = CreateProcessA(NULL, cmd_mut, NULL, NULL, TRUE, 0, NULL,
-                           cwd && cwd[0] ? cwd : NULL, &si, &pi);
-  free(cmd_mut);
-  CloseHandle(wr);
-  if (nul != INVALID_HANDLE_VALUE)
-    CloseHandle(nul);
-  if (!ok) {
-    CloseHandle(rd);
-    return -1;
-  }
-
-  size_t cap = 4096, len = 0;
-  char *buf = malloc(cap);
-  if (!buf) {
-    CloseHandle(rd);
-    CloseHandle(pi.hProcess);
-    CloseHandle(pi.hThread);
-    return -1;
-  }
-  buf[0] = 0;
-  int truncated = 0, killed = 0;
-  double deadline = os_now_ms() + run_timeout_s() * 1000.0;
-  for (;;) {
-    DWORD avail = 0;
-    if (!PeekNamedPipe(rd, NULL, 0, NULL, &avail, NULL))
-      break; /* writer closed */
-    if (avail > 0) {
-      char tmp[4096];
-      DWORD n = 0;
-      if (!ReadFile(rd, tmp, sizeof(tmp), &n, NULL) || n == 0)
-        break;
-      cap_append(&buf, &len, &cap, max_out, tmp, n, &truncated);
-      continue;
-    }
-    if (WaitForSingleObject(pi.hProcess, 50) == WAIT_OBJECT_0) {
-      /* drain what is left */
-      while (PeekNamedPipe(rd, NULL, 0, NULL, &avail, NULL) && avail > 0) {
-        char tmp[4096];
-        DWORD n = 0;
-        if (!ReadFile(rd, tmp, sizeof(tmp), &n, NULL) || n == 0)
-          break;
-        cap_append(&buf, &len, &cap, max_out, tmp, n, &truncated);
-      }
-      break;
-    }
-    if ((g_run_cancel && *g_run_cancel) || os_now_ms() > deadline) {
-      killed = (g_run_cancel && *g_run_cancel) ? 2 : 1;
-      TerminateProcess(pi.hProcess, killed == 1 ? 124 : 130);
-      break;
-    }
-  }
-  CloseHandle(rd);
-  WaitForSingleObject(pi.hProcess, INFINITE);
-  DWORD code = 1;
-  GetExitCodeProcess(pi.hProcess, &code);
-  if (truncated)
-    cap_note(&buf, &len, &cap, "\n...(output truncated)\n");
-  if (killed == 1) {
-    char note[96];
-    snprintf(note, sizeof(note), "\n[cst: killed after %ds timeout]\n",
-             run_timeout_s());
-    cap_note(&buf, &len, &cap, note);
-    code = 124;
-  } else if (killed == 2) {
-    cap_note(&buf, &len, &cap, "\n[cst: cancelled]\n");
-    code = 130;
-  }
-  CloseHandle(pi.hProcess);
-  CloseHandle(pi.hThread);
-  buf[len] = 0;
-  r->out = buf;
-  r->out_len = len;
-  r->exit_code = (int)code;
-  return 0;
-}
-
-int os_run_capture_ex(const char *cwd, const char *const argv[],
-                      size_t max_out, os_run_result_t *r,
-                      os_child_hook_fn child_hook, void *ud) {
-  (void)child_hook;
-  (void)ud;
-  return os_run_capture(cwd, argv, max_out, r);
-}
-#else
+#ifndef _WIN32
 static void cloexec(int fd) {
   int fl = fcntl(fd, F_GETFD);
   if (fl >= 0)
@@ -685,7 +595,7 @@ int os_run_capture_ex(const char *cwd, const char *const argv[],
   int truncated = 0, killed = 0;
   int status = 0, reaped = 0, bg_killed = 0;
   double reaped_at = 0, killed_at = 0;
-  double deadline = os_now_ms() + run_timeout_s() * 1000.0;
+  double deadline = os_now_ms() + os_run_timeout_effective() * 1000.0;
   for (;;) {
     struct pollfd pfd = {pipefd[0], POLLIN, 0};
     int pr = poll(&pfd, 1, 100);
@@ -697,7 +607,7 @@ int os_run_capture_ex(const char *cwd, const char *const argv[],
       if (n == 0)
         break; /* every writer closed */
       if (n > 0)
-        cap_append(&buf, &len, &cap, max_out, tmp, (size_t)n, &truncated);
+        os_cap_append(&buf, &len, &cap, max_out, tmp, (size_t)n, &truncated);
       else if (errno != EINTR && errno != EAGAIN)
         break;
     }
@@ -733,9 +643,9 @@ int os_run_capture_ex(const char *cwd, const char *const argv[],
     waitpid(pid, &status, 0);
   }
   if (truncated)
-    cap_note(&buf, &len, &cap, "\n...(output truncated)\n");
+    os_cap_note(&buf, &len, &cap, "\n...(output truncated)\n");
   if (bg_killed)
-    cap_note(&buf, &len, &cap,
+    os_cap_note(&buf, &len, &cap,
              "\n[cst: background processes left running were stopped]\n");
   r->out = buf;
   r->out_len = len;
@@ -743,11 +653,11 @@ int os_run_capture_ex(const char *cwd, const char *const argv[],
   if (killed == 1) {
     char note[96];
     snprintf(note, sizeof(note), "\n[cst: killed after %ds timeout]\n",
-             run_timeout_s());
-    cap_note(&r->out, &r->out_len, &cap, note);
+             os_run_timeout_effective());
+    os_cap_note(&r->out, &r->out_len, &cap, note);
     r->exit_code = 124;
   } else if (killed == 2) {
-    cap_note(&r->out, &r->out_len, &cap, "\n[cst: cancelled]\n");
+    os_cap_note(&r->out, &r->out_len, &cap, "\n[cst: cancelled]\n");
     r->exit_code = 130;
   }
   return 0;
@@ -759,40 +669,64 @@ int os_run_shell_c(const char *cwd, const char *cmd, size_t max_out,
   return os_run_shell_ex(cwd, cmd, max_out, r, NULL, NULL);
 }
 
+/* busybox: busybox sh -c cmd ; /bin/sh: sh -c cmd. argv needs 5 slots and
+ * points into shell. */
+static int shell_argv(char *shell, size_t shell_sz, const char *cmd,
+                      const char *argv[5]) {
+  if (!cmd || os_resolve_shell(shell, shell_sz) != 0)
+    return -1;
+  const char *base = shell;
+  const char *s = strrchr(shell, '/');
+#ifdef _WIN32
+  const char *s2 = strrchr(shell, '\\');
+  if (s2 && (!s || s2 > s))
+    s = s2;
+#endif
+  if (s)
+    base = s + 1;
+  int i = 0;
+  argv[i++] = shell;
+  if (strncmp(base, "busybox", 7) == 0)
+    argv[i++] = "sh";
+  argv[i++] = "-c";
+  argv[i++] = cmd;
+  argv[i] = NULL;
+  return 0;
+}
+
 int os_run_shell_ex(const char *cwd, const char *cmd, size_t max_out,
                     os_run_result_t *r, os_child_hook_fn child_hook,
                     void *ud) {
-  if (!cmd || !r)
-    return -1;
   char shell[OS_PATH_MAX];
-  if (os_resolve_shell(shell, sizeof(shell)) != 0)
+  const char *argv[5];
+  if (!r || shell_argv(shell, sizeof(shell), cmd, argv) != 0)
     return -1;
-
-  /* busybox: busybox sh -c cmd ; /bin/sh: sh -c cmd */
-  int is_busybox = 0;
-  {
-    const char *base = shell;
-    const char *s = strrchr(shell, '/');
-#ifdef _WIN32
-    const char *s2 = strrchr(shell, '\\');
-    if (s2 && (!s || s2 > s))
-      s = s2;
-#endif
-    if (s)
-      base = s + 1;
-    if (strncmp(base, "busybox", 7) == 0)
-      is_busybox = 1;
-  }
-
-  if (is_busybox) {
-    const char *argv[] = {shell, "sh", "-c", cmd, NULL};
-    return os_run_capture_ex(cwd, argv, max_out, r, child_hook, ud);
-  } else {
-    const char *argv[] = {shell, "-c", cmd, NULL};
-    return os_run_capture_ex(cwd, argv, max_out, r, child_hook, ud);
-  }
+  return os_run_capture_ex(cwd, argv, max_out, r, child_hook, ud);
 }
 
+#ifdef _WIN32
+int os_run_shell_token(const char *cwd, const char *cmd, size_t max_out,
+                       os_run_result_t *r, void *token,
+                       const char *const env_add[]) {
+  char shell[OS_PATH_MAX];
+  const char *argv[5];
+  if (!r || shell_argv(shell, sizeof(shell), cmd, argv) != 0)
+    return -1;
+  return os_run_capture_token(cwd, argv, max_out, r, token, env_add);
+}
+#endif
+
+#ifndef _WIN32
+int os_console_init(void) { return 0; }
+
+char *os_output_to_utf8(const char *s, size_t n, size_t *out_len) {
+  (void)s;
+  (void)n;
+  (void)out_len;
+  return NULL;
+}
+#endif
+
 void os_localtime(const time_t *t, struct tm *out) {
   if (!t || !out)
     return;
@@ -811,16 +745,13 @@ int os_getpid(void) {
 #endif
 }
 
+#ifndef _WIN32
 int os_chmod_private(const char *path) {
   if (!path)
     return -1;
-#ifdef _WIN32
-  (void)path;
-  return 0;
-#else
   return chmod(path, 0600);
-#endif
 }
+#endif
 
 typedef struct {
   os_task_fn fn;
@@ -905,133 +836,7 @@ int os_cancel_requested(void) { return g_run_cancel && *g_run_cancel; }
 
 volatile int *os_get_cancel_flag(void) { return g_run_cancel; }
 
-#ifdef _WIN32
-static void win_quote_arg(char *out, size_t out_sz, size_t *pos,
-                          const char *a) {
-  int need_q = !a[0] || strpbrk(a, " \t\"") != NULL;
-  if (need_q && *pos + 1 < out_sz)
-    out[(*pos)++] = '"';
-  for (const char *p = a; *p && *pos + 2 < out_sz; p++) {
-    if (*p == '"')
-      out[(*pos)++] = '\\';
-    out[(*pos)++] = *p;
-  }
-  if (need_q && *pos + 1 < out_sz)
-    out[(*pos)++] = '"';
-  out[*pos] = 0;
-}
-
-int os_proc_spawn(const char *cwd, const char *const argv[],
-                  const char *const env_add[], const char *stderr_path,
-                  os_proc_t *p) {
-  memset(p, 0, sizeof(*p));
-  if (!argv || !argv[0])
-    return -1;
-  char cmdline[16384];
-  size_t pos = 0;
-  cmdline[0] = 0;
-  for (int i = 0; argv[i]; i++) {
-    if (i && pos + 1 < sizeof(cmdline))
-      cmdline[pos++] = ' ';
-    win_quote_arg(cmdline, sizeof(cmdline), &pos, argv[i]);
-  }
-  for (int i = 0; env_add && env_add[i]; i++)
-    _putenv(env_add[i]); /* inherited by the child */
-  SECURITY_ATTRIBUTES sa = {0};
-  sa.nLength = sizeof(sa);
-  sa.bInheritHandle = TRUE;
-  HANDLE in_r = NULL, in_w = NULL, out_r = NULL, out_w = NULL;
-  if (!CreatePipe(&in_r, &in_w, &sa, 0))
-    return -1;
-  if (!CreatePipe(&out_r, &out_w, &sa, 0)) {
-    CloseHandle(in_r);
-    CloseHandle(in_w);
-    return -1;
-  }
-  SetHandleInformation(in_w, HANDLE_FLAG_INHERIT, 0);
-  SetHandleInformation(out_r, HANDLE_FLAG_INHERIT, 0);
-  HANDLE err = CreateFileA(stderr_path ? stderr_path : "NUL", GENERIC_WRITE,
-                           FILE_SHARE_READ | FILE_SHARE_WRITE, &sa,
-                           CREATE_ALWAYS, 0, NULL);
-  STARTUPINFOA si = {0};
-  si.cb = sizeof(si);
-  si.dwFlags = STARTF_USESTDHANDLES;
-  si.hStdInput = in_r;
-  si.hStdOutput = out_w;
-  si.hStdError = err != INVALID_HANDLE_VALUE ? err : out_w;
-  PROCESS_INFORMATION pi = {0};
-  BOOL ok = CreateProcessA(NULL, cmdline, NULL, NULL, TRUE, CREATE_NO_WINDOW,
-                           NULL, cwd && cwd[0] ? cwd : NULL, &si, &pi);
-  CloseHandle(in_r);
-  CloseHandle(out_w);
-  if (err != INVALID_HANDLE_VALUE)
-    CloseHandle(err);
-  if (!ok) {
-    CloseHandle(in_w);
-    CloseHandle(out_r);
-    return -1;
-  }
-  CloseHandle(pi.hThread);
-  p->proc = pi.hProcess;
-  p->in_w = in_w;
-  p->out_r = out_r;
-  return 0;
-}
-
-int os_proc_write(os_proc_t *p, const char *data, size_t n) {
-  while (n > 0) {
-    DWORD w = 0;
-    if (!p->in_w || !WriteFile((HANDLE)p->in_w, data, (DWORD)n, &w, NULL) ||
-        w == 0)
-      return -1;
-    data += w;
-    n -= w;
-  }
-  return 0;
-}
-
-long os_proc_read(os_proc_t *p, char *buf, size_t n, int timeout_ms) {
-  if (!p->out_r)
-    return -1;
-  double deadline = os_now_ms() + timeout_ms;
-  for (;;) {
-    DWORD avail = 0;
-    if (!PeekNamedPipe((HANDLE)p->out_r, NULL, 0, NULL, &avail, NULL))
-      return GetLastError() == ERROR_BROKEN_PIPE ? 0 : -1;
-    if (avail > 0)
-      break;
-    if (os_now_ms() >= deadline)
-      return -2;
-    Sleep(10);
-  }
-  DWORD r = 0;
-  if (!ReadFile((HANDLE)p->out_r, buf, (DWORD)n, &r, NULL))
-    return GetLastError() == ERROR_BROKEN_PIPE ? 0 : -1;
-  return (long)r;
-}
-
-void os_proc_close_stdin(os_proc_t *p) {
-  if (p->in_w) {
-    CloseHandle((HANDLE)p->in_w);
-    p->in_w = NULL;
-  }
-}
-
-void os_proc_kill(os_proc_t *p) {
-  os_proc_close_stdin(p);
-  if (p->proc) {
-    if (WaitForSingleObject((HANDLE)p->proc, 500) != WAIT_OBJECT_0)
-      TerminateProcess((HANDLE)p->proc, 1);
-    WaitForSingleObject((HANDLE)p->proc, 2000);
-    CloseHandle((HANDLE)p->proc);
-    p->proc = NULL;
-  }
-  if (p->out_r) {
-    CloseHandle((HANDLE)p->out_r);
-    p->out_r = NULL;
-  }
-}
-#else
+#ifndef _WIN32
 int os_proc_spawn(const char *cwd, const char *const argv[],
                   const char *const env_add[], const char *stderr_path,
                   os_proc_t *p) {
diff --git a/src/os_internal.h b/src/os_internal.h
new file mode 100644
index 0000000..8c8f62e
--- /dev/null
+++ b/src/os_internal.h
@@ -0,0 +1,14 @@
+/* Shared between os_compat.c and os_win.c; not part of the public API. */
+#ifndef CST_OS_INTERNAL_H
+#define CST_OS_INTERNAL_H
+
+#include <stddef.h>
+
+/* CST_SHELL_TIMEOUT / os_set_run_timeout / 120 s */
+int os_run_timeout_effective(void);
+/* Append to a capture buffer, keeping at most max_out bytes. */
+int os_cap_append(char **buf, size_t *len, size_t *cap, size_t max_out,
+                  const char *data, size_t n, int *truncated);
+void os_cap_note(char **buf, size_t *len, size_t *cap, const char *note);
+
+#endif
diff --git a/src/os_win.c b/src/os_win.c
new file mode 100644
index 0000000..67f35aa
--- /dev/null
+++ b/src/os_win.c
@@ -0,0 +1,934 @@
+/* Windows side of os_compat: every string crossing the OS boundary is UTF-8
+ * inside cst-agent and UTF-16 at the Win32 W APIs. The embedded manifest also
+ * sets the process code page to UTF-8, so CRT calls (fopen, getenv, argv)
+ * see UTF-8 too. */
+#ifdef _WIN32
+
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#include "os_compat.h"
+#include "cst_util.h"
+#include "os_internal.h"
+
+#include <locale.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <windows.h>
+
+#include <aclapi.h>
+#include <sddl.h>
+
+wchar_t *os_utf8_to_wide(const char *s) {
+  if (!s)
+    return NULL;
+  int n = MultiByteToWideChar(CP_UTF8, 0, s, -1, NULL, 0);
+  if (n <= 0)
+    return NULL;
+  wchar_t *w = malloc((size_t)n * sizeof(wchar_t));
+  if (w && MultiByteToWideChar(CP_UTF8, 0, s, -1, w, n) <= 0) {
+    free(w);
+    return NULL;
+  }
+  return w;
+}
+
+char *os_wide_to_utf8(const wchar_t *w) {
+  if (!w)
+    return NULL;
+  int n = WideCharToMultiByte(CP_UTF8, 0, w, -1, NULL, 0, NULL, NULL);
+  if (n <= 0)
+    return NULL;
+  char *s = malloc((size_t)n);
+  if (s && WideCharToMultiByte(CP_UTF8, 0, w, -1, s, n, NULL, NULL) <= 0) {
+    free(s);
+    return NULL;
+  }
+  return s;
+}
+
+static UINT g_old_cp, g_old_out_cp;
+
+static void console_restore(void) {
+  if (g_old_cp)
+    SetConsoleCP(g_old_cp);
+  if (g_old_out_cp)
+    SetConsoleOutputCP(g_old_out_cp);
+}
+
+int os_console_init(void) {
+  static int done;
+  if (done)
+    return GetACP() == CP_UTF8 ? 0 : -1;
+  done = 1;
+  g_old_cp = GetConsoleCP();
+  g_old_out_cp = GetConsoleOutputCP();
+  if (g_old_cp || g_old_out_cp) {
+    SetConsoleCP(CP_UTF8);
+    SetConsoleOutputCP(CP_UTF8);
+    atexit(console_restore);
+  }
+  setlocale(LC_ALL, ".UTF-8");
+  /* children inherit these: Python otherwise writes the ANSI code page to pipes */
+  if (!getenv("PYTHONUTF8"))
+    _putenv_s("PYTHONUTF8", "1");
+  if (!getenv("PYTHONIOENCODING"))
+    _putenv_s("PYTHONIOENCODING", "utf-8");
+  return GetACP() == CP_UTF8 ? 0 : -1;
+}
+
+/* The system locale's code page. GetOEMCP()/GetACP() say 65001 once the
+ * manifest makes this process UTF-8, but children without one (cmd, most
+ * console tools) still write the system's OEM code page, e.g. 936. */
+static UINT system_cp(LCTYPE which) {
+  wchar_t b[8];
+  if (!GetLocaleInfoW(LOCALE_SYSTEM_DEFAULT, which, b, 8))
+    return 0;
+  return (UINT)wcstoul(b, NULL, 10);
+}
+
+char *os_output_to_utf8(const char *s, size_t n, size_t *out_len) {
+  if (!s || cst_utf8_valid(s, n))
+    return NULL;
+  UINT cps[] = {GetConsoleOutputCP(), system_cp(LOCALE_IDEFAULTCODEPAGE),
+                system_cp(LOCALE_IDEFAULTANSICODEPAGE), GetOEMCP(), GetACP()};
+  for (size_t i = 0; i < sizeof(cps) / sizeof(cps[0]); i++) {
+    UINT cp = cps[i];
+    if (!cp || cp == CP_UTF8)
+      continue;
+    int wn = MultiByteToWideChar(cp, MB_ERR_INVALID_CHARS, s, (int)n, NULL, 0);
+    if (wn <= 0)
+      continue;
+    wchar_t *w = malloc((size_t)wn * sizeof(wchar_t));
+    if (!w)
+      return NULL;
+    MultiByteToWideChar(cp, 0, s, (int)n, w, wn);
+    int un = WideCharToMultiByte(CP_UTF8, 0, w, wn, NULL, 0, NULL, NULL);
+    char *u = un > 0 ? malloc((size_t)un + 1) : NULL;
+    if (u) {
+      WideCharToMultiByte(CP_UTF8, 0, w, wn, u, un, NULL, NULL);
+      u[un] = 0;
+      if (out_len)
+        *out_len = (size_t)un;
+    }
+    free(w);
+    return u;
+  }
+  return NULL;
+}
+
+/* --- paths --------------------------------------------------------------- */
+
+/* UTF-8 path -> wide, with the \\?\ prefix once it gets near MAX_PATH so
+ * deep trees work without the LongPathsEnabled policy. */
+static wchar_t *wpath(const char *p) {
+  wchar_t *w = os_utf8_to_wide(p);
+  if (!w || wcslen(w) < MAX_PATH - 12)
+    return w;
+  DWORD n = GetFullPathNameW(w, 0, NULL, NULL);
+  wchar_t *f = n ? malloc(n * sizeof(wchar_t)) : NULL;
+  wchar_t *out = n ? malloc((n + 8) * sizeof(wchar_t)) : NULL;
+  if (!f || !out || GetFullPathNameW(w, n, f, NULL) == 0) {
+    free(f);
+    free(out);
+    return w;
+  }
+  free(w);
+  if (wcsncmp(f, L"\\\\?\\", 4) == 0) {
+    wcscpy(out, f);
+  } else if (f[0] == L'\\' && f[1] == L'\\') { /* \\srv\share -> \\?\UNC\srv\share */
+    wcscpy(out, L"\\\\?\\UNC");
+    wcscat(out, f + 1);
+  } else {
+    wcscpy(out, L"\\\\?\\");
+    wcscat(out, f);
+  }
+  free(f);
+  return out;
+}
+
+/* Wide path from the OS -> UTF-8 with '/' separators, no \\?\ prefix and a
+ * lowercase drive letter (stable for prefix compares). */
+static int path_out(const wchar_t *w, char *out, size_t out_sz) {
+  const char *lead = "";
+  if (wcsncmp(w, L"\\\\?\\UNC\\", 8) == 0) {
+    lead = "\\\\"; /* \\?\UNC\srv\share -> \\srv\share */
+    w += 8;
+  } else if (wcsncmp(w, L"\\\\?\\", 4) == 0) {
+    w += 4;
+  }
+  char *u = os_wide_to_utf8(w);
+  if (!u)
+    return -1;
+  int n = snprintf(out, out_sz, "%s%s", lead, u);
+  free(u);
+  if (n < 0 || (size_t)n >= out_sz)
+    return -1;
+  os_path_norm_slashes(out);
+  if (out[0] >= 'A' && out[0] <= 'Z' && out[1] == ':')
+    out[0] = (char)(out[0] - 'A' + 'a');
+  return 0;
+}
+
+int os_realpath(const char *path, char *out, size_t out_sz) {
+  if (!path || !path[0] || !out || out_sz < 2)
+    return -1;
+  wchar_t *w = wpath(path);
+  if (!w)
+    return -1;
+  HANDLE h = CreateFileW(w, 0,
+                         FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                         NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
+  free(w);
+  if (h == INVALID_HANDLE_VALUE)
+    return -1;
+  wchar_t stackbuf[MAX_PATH + 16], *buf = stackbuf;
+  DWORD n = GetFinalPathNameByHandleW(h, buf, MAX_PATH + 16,
+                                      FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
+  if (n >= MAX_PATH + 16) {
+    buf = malloc((n + 1) * sizeof(wchar_t));
+    n = buf ? GetFinalPathNameByHandleW(h, buf, n + 1,
+                                        FILE_NAME_NORMALIZED | VOLUME_NAME_DOS)
+            : 0;
+  }
+  CloseHandle(h);
+  int rc = n ? path_out(buf, out, out_sz) : -1;
+  if (buf != stackbuf)
+    free(buf);
+  return rc;
+}
+
+/* NTFS names are case-insensitive: compare the prefix the way the OS does. */
+int os_path_under(const char *root, const char *path) {
+  if (!root || !path)
+    return 0;
+  wchar_t *wr = os_utf8_to_wide(root), *wp = os_utf8_to_wide(path);
+  int ok = 0;
+  if (wr && wp) {
+    size_t rl = wcslen(wr);
+    if (wcslen(wp) >= rl &&
+        (rl == 0 || CompareStringOrdinal(wr, (int)rl, wp, (int)rl, TRUE) ==
+                        CSTR_EQUAL)) {
+      wchar_t c = wp[rl];
+      ok = c == 0 || c == L'/' || c == L'\\' ||
+           (rl && (wr[rl - 1] == L'/' || wr[rl - 1] == L'\\'));
+    }
+  }
+  free(wr);
+  free(wp);
+  return ok;
+}
+
+static int reparse_is_link(DWORD attrs, DWORD tag) {
+  return (attrs & FILE_ATTRIBUTE_REPARSE_POINT) &&
+         (tag == IO_REPARSE_TAG_SYMLINK || tag == IO_REPARSE_TAG_MOUNT_POINT);
+}
+
+/* --- directories ------------------------------------------------------- */
+
+struct os_dir {
+  HANDLE h;
+  int pending; /* fd holds an entry not yet returned */
+  WIN32_FIND_DATAW fd;
+  char name[MAX_PATH * 4];
+  os_dirent_t ent;
+};
+
+os_dir_t *os_dir_open(const char *path) {
+  if (!path || !path[0])
+    return NULL;
+  size_t L = strlen(path);
+  char *pat = malloc(L + 3);
+  if (!pat)
+    return NULL;
+  memcpy(pat, path, L);
+  if (path[L - 1] != '/' && path[L - 1] != '\\')
+    pat[L++] = '\\';
+  pat[L++] = '*';
+  pat[L] = 0;
+  wchar_t *w = wpath(pat);
+  free(pat);
+  os_dir_t *d = w ? calloc(1, sizeof(*d)) : NULL;
+  if (!d) {
+    free(w);
+    return NULL;
+  }
+  d->h = FindFirstFileExW(w, FindExInfoBasic, &d->fd, FindExSearchNameMatch,
+                          NULL, FIND_FIRST_EX_LARGE_FETCH);
+  free(w);
+  if (d->h == INVALID_HANDLE_VALUE) {
+    DWORD e = GetLastError();
+    if (e != ERROR_FILE_NOT_FOUND) { /* an empty drive root has no entries */
+      free(d);
+      return NULL;
+    }
+  } else {
+    d->pending = 1;
+  }
+  return d;
+}
+
+const os_dirent_t *os_dir_next(os_dir_t *d) {
+  if (!d || d->h == INVALID_HANDLE_VALUE)
+    return NULL;
+  for (;;) {
+    if (!d->pending && !FindNextFileW(d->h, &d->fd))
+      return NULL;
+    d->pending = 0;
+    const wchar_t *n = d->fd.cFileName;
+    if (wcscmp(n, L".") == 0 || wcscmp(n, L"..") == 0)
+      continue;
+    if (WideCharToMultiByte(CP_UTF8, 0, n, -1, d->name, (int)sizeof(d->name),
+                            NULL, NULL) <= 0)
+      continue;
+    DWORD a = d->fd.dwFileAttributes;
+    d->ent.name = d->name;
+    d->ent.is_link = reparse_is_link(a, d->fd.dwReserved0);
+    d->ent.is_dir = !d->ent.is_link && (a & FILE_ATTRIBUTE_DIRECTORY);
+    return &d->ent;
+  }
+}
+
+void os_dir_close(os_dir_t *d) {
+  if (!d)
+    return;
+  if (d->h != INVALID_HANDLE_VALUE)
+    FindClose(d->h);
+  free(d);
+}
+
+static double filetime_secs(FILETIME ft) {
+  ULONGLONG t = ((ULONGLONG)ft.dwHighDateTime << 32) | ft.dwLowDateTime;
+  return (double)t / 1e7 - 11644473600.0;
+}
+
+int os_lstat(const char *path, os_stat_t *st) {
+  memset(st, 0, sizeof(*st));
+  wchar_t *w = path ? wpath(path) : NULL;
+  if (!w)
+    return -1;
+  WIN32_FILE_ATTRIBUTE_DATA fa;
+  if (!GetFileAttributesExW(w, GetFileExInfoStandard, &fa)) {
+    free(w);
+    return -1;
+  }
+  DWORD a = fa.dwFileAttributes;
+  if (a & FILE_ATTRIBUTE_REPARSE_POINT) {
+    WIN32_FIND_DATAW fd;
+    HANDLE h = FindFirstFileW(w, &fd);
+    if (h != INVALID_HANDLE_VALUE) {
+      st->is_link = reparse_is_link(a, fd.dwReserved0);
+      FindClose(h);
+    }
+  }
+  free(w);
+  st->is_dir = !st->is_link && (a & FILE_ATTRIBUTE_DIRECTORY);
+  st->is_reg = !st->is_link && !(a & FILE_ATTRIBUTE_DIRECTORY);
+  st->size = (long long)(((ULONGLONG)fa.nFileSizeHigh << 32) | fa.nFileSizeLow);
+  st->mtime = filetime_secs(fa.ftLastWriteTime);
+  return 0;
+}
+
+int os_rename_replace(const char *from, const char *to) {
+  wchar_t *wf = wpath(from), *wt = wpath(to);
+  int ok = wf && wt &&
+           MoveFileExW(wf, wt, MOVEFILE_REPLACE_EXISTING | MOVEFILE_COPY_ALLOWED);
+  free(wf);
+  free(wt);
+  return ok ? 0 : -1;
+}
+
+/* --- processes ----------------------------------------------------------- */
+
+/* One argument the way CommandLineToArgvW and the CRT split it again. */
+static void cmdline_arg(cst_buf_t *b, const char *a) {
+  if (a[0] && !strpbrk(a, " \t\n\v\"")) {
+    cst_buf_puts(b, a);
+    return;
+  }
+  cst_buf_puts(b, "\"");
+  for (const char *p = a;; p++) {
+    size_t bs = 0;
+    while (*p == '\\') {
+      bs++;
+      p++;
+    }
+    if (!*p) {
+      for (size_t i = 0; i < bs * 2; i++)
+        cst_buf_puts(b, "\\");
+      break;
+    }
+    for (size_t i = 0; i < (*p == '"' ? bs * 2 + 1 : bs); i++)
+      cst_buf_puts(b, "\\");
+    cst_buf_append(b, p, 1);
+  }
+  cst_buf_puts(b, "\"");
+}
+
+static wchar_t *build_cmdline(const char *const argv[]) {
+  cst_buf_t b = {0};
+  for (int i = 0; argv[i]; i++) {
+    if (i)
+      cst_buf_puts(&b, " ");
+    cmdline_arg(&b, argv[i]);
+  }
+  wchar_t *w = b.buf ? os_utf8_to_wide(b.buf) : NULL;
+  cst_buf_free(&b);
+  return w;
+}
+
+static size_t env_name_len(const wchar_t *e) {
+  const wchar_t *eq = wcschr(e + 1, L'='); /* "=C:=C:\x" hides a leading '=' */
+  return eq ? (size_t)(eq - e) : wcslen(e);
+}
+
+static int env_cmp(const void *a, const void *b) {
+  const wchar_t *x = *(const wchar_t *const *)a, *y = *(const wchar_t *const *)b;
+  return CompareStringOrdinal(x, (int)env_name_len(x), y, (int)env_name_len(y),
+                              TRUE) -
+         CSTR_EQUAL;
+}
+
+/* The inherited environment with env_add ("KEY=VALUE") layered on top, as a
+ * sorted CREATE_UNICODE_ENVIRONMENT block; NULL = inherit unchanged. */
+static wchar_t *env_block(const char *const env_add[]) {
+  if (!env_add || !env_add[0])
+    return NULL;
+  size_t nadd = 0, ncur = 0;
+  while (env_add[nadd])
+    nadd++;
+  wchar_t *cur = GetEnvironmentStringsW();
+  for (const wchar_t *e = cur; e && *e; e += wcslen(e) + 1)
+    ncur++;
+  wchar_t **add = calloc(nadd, sizeof(*add));
+  wchar_t **v = calloc(ncur + nadd, sizeof(*v));
+  wchar_t *blk = NULL;
+  size_t n = 0, total = 1;
+  if (!add || !v)
+    goto out;
+  for (size_t i = 0; i < nadd; i++)
+    if (!(add[i] = os_utf8_to_wide(env_add[i])))
+      goto out;
+  for (wchar_t *e = cur; e && *e; e += wcslen(e) + 1) {
+    int shadowed = 0;
+    for (size_t i = 0; i < nadd && !shadowed; i++)
+      shadowed = env_cmp(&e, &add[i]) == 0;
+    if (!shadowed)
+      v[n++] = e;
+  }
+  for (size_t i = 0; i < nadd; i++) {
+    int dup = 0; /* a later entry for the same name wins */
+    for (size_t k = i + 1; k < nadd && !dup; k++)
+      dup = env_cmp(&add[i], &add[k]) == 0;
+    if (!dup)
+      v[n++] = add[i];
+  }
+  qsort(v, n, sizeof(*v), env_cmp);
+  for (size_t i = 0; i < n; i++)
+    total += wcslen(v[i]) + 1;
+  blk = malloc(total * sizeof(wchar_t));
+  if (blk) {
+    wchar_t *o = blk;
+    for (size_t i = 0; i < n; i++) {
+      size_t l = wcslen(v[i]) + 1;
+      memcpy(o, v[i], l * sizeof(wchar_t));
+      o += l;
+    }
+    *o = 0;
+  }
+out:
+  for (size_t i = 0; add && i < nadd; i++)
+    free(add[i]);
+  free(add);
+  free(v);
+  if (cur)
+    FreeEnvironmentStringsW(cur);
+  return blk;
+}
+
+static HANDLE new_job(void) {
+  HANDLE job = CreateJobObjectW(NULL, NULL);
+  if (!job)
+    return NULL;
+  JOBOBJECT_EXTENDED_LIMIT_INFORMATION li;
+  memset(&li, 0, sizeof(li));
+  li.BasicLimitInformation.LimitFlags =
+      JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE |
+      JOB_OBJECT_LIMIT_DIE_ON_UNHANDLED_EXCEPTION;
+  SetInformationJobObject(job, JobObjectExtendedLimitInformation, &li,
+                          sizeof(li));
+  return job;
+}
+
+static DWORD job_active(HANDLE job) {
+  JOBOBJECT_BASIC_ACCOUNTING_INFORMATION ai;
+  if (!job || !QueryInformationJobObject(job,
+                                         JobObjectBasicAccountingInformation,
+                                         &ai, sizeof(ai), NULL))
+    return 0;
+  return ai.ActiveProcesses;
+}
+
+/* Children still running after the shell exited. A child started without
+ * our console (the sandbox) has its own conhost.exe, which leaves the job a
+ * moment after its client, so give the job a short while to drain. */
+static int job_lingers(HANDLE job) {
+  for (int i = 0; i < 50 && job_active(job) > 0; i++)
+    Sleep(10);
+  return job_active(job) > 0;
+}
+
+/* Start argv suspended, put it in a fresh kill-on-close job, then resume.
+ * Only in/out/err are inherited (PROC_THREAD_ATTRIBUTE_HANDLE_LIST), so a
+ * concurrent spawn on another thread never leaks into this child. */
+static int spawn(const char *cwd, const char *const argv[],
+                 const char *const env_add[], HANDLE token, HANDLE in,
+                 HANDLE out, HANDLE err, HANDLE *proc, HANDLE *job,
+                 DWORD *error) {
+  *proc = *job = NULL;
+  *error = ERROR_OUTOFMEMORY;
+  wchar_t *cmd = build_cmdline(argv);
+  wchar_t *wcwd = cwd && cwd[0] ? os_utf8_to_wide(cwd) : NULL;
+  wchar_t *env = env_block(env_add);
+  HANDLE inherit[3];
+  int ninh = 0;
+  HANDLE std3[3] = {in, out, err};
+  for (int i = 0; i < 3; i++) {
+    int seen = !std3[i] || std3[i] == INVALID_HANDLE_VALUE;
+    for (int k = 0; k < ninh && !seen; k++)
+      seen = inherit[k] == std3[i];
+    if (!seen)
+      inherit[ninh++] = std3[i];
+  }
+  SIZE_T asz = 0;
+  InitializeProcThreadAttributeList(NULL, 1, 0, &asz);
+  LPPROC_THREAD_ATTRIBUTE_LIST attrs = malloc(asz);
+  int ok = 0;
+  if (cmd && (!cwd || !cwd[0] || wcwd) && (!env_add || !env_add[0] || env) &&
+      attrs && InitializeProcThreadAttributeList(attrs, 1, 0, &asz)) {
+    if (UpdateProcThreadAttribute(attrs, 0, PROC_THREAD_ATTRIBUTE_HANDLE_LIST,
+                                  inherit, (SIZE_T)ninh * sizeof(HANDLE), NULL,
+                                  NULL)) {
+      STARTUPINFOEXW si;
+      memset(&si, 0, sizeof(si));
+      si.StartupInfo.cb = sizeof(si);
+      si.StartupInfo.dwFlags = STARTF_USESTDHANDLES;
+      si.StartupInfo.hStdInput = in;
+      si.StartupInfo.hStdOutput = out;
+      si.StartupInfo.hStdError = err;
+      si.lpAttributeList = attrs;
+      /* Share our console when there is one (children then see its UTF-8
+       * code page); the sandbox token cannot attach to it. */
+      DWORD flags = CREATE_SUSPENDED | CREATE_UNICODE_ENVIRONMENT |
+                    CREATE_NEW_PROCESS_GROUP | EXTENDED_STARTUPINFO_PRESENT;
+      if (token || !GetConsoleWindow())
+        flags |= CREATE_NO_WINDOW;
+      PROCESS_INFORMATION pi;
+      memset(&pi, 0, sizeof(pi));
+      ok = token ? CreateProcessAsUserW(token, NULL, cmd, NULL, NULL, TRUE,
+                                        flags, env, wcwd, &si.StartupInfo, &pi)
+                 : CreateProcessW(NULL, cmd, NULL, NULL, TRUE, flags, env, wcwd,
+                                  &si.StartupInfo, &pi);
+      if (ok) {
+        *job = new_job();
+        if (*job && !AssignProcessToJobObject(*job, pi.hProcess)) {
+          CloseHandle(*job);
+          *job = NULL;
+        }
+        ResumeThread(pi.hThread);
+        CloseHandle(pi.hThread);
+        *proc = pi.hProcess;
+      } else {
+        *error = GetLastError();
+      }
+    }
+    DeleteProcThreadAttributeList(attrs);
+  }
+  free(attrs);
+  free(cmd);
+  free(wcwd);
+  free(env);
+  return ok ? 0 : -1;
+}
+
+int os_run_capture_token(const char *cwd, const char *const argv[],
+                         size_t max_out, os_run_result_t *r, void *token,
+                         const char *const env_add[]) {
+  if (!argv || !argv[0] || !r)
+    return -1;
+  if (max_out == 0)
+    max_out = 512 * 1024;
+  memset(r, 0, sizeof(*r));
+  SECURITY_ATTRIBUTES sa = {sizeof(sa), NULL, TRUE};
+  HANDLE rd = NULL, wr = NULL;
+  if (!CreatePipe(&rd, &wr, &sa, 64 * 1024))
+    return -1;
+  SetHandleInformation(rd, HANDLE_FLAG_INHERIT, 0);
+  HANDLE nul = CreateFileW(L"NUL", GENERIC_READ,
+                           FILE_SHARE_READ | FILE_SHARE_WRITE, &sa,
+                           OPEN_EXISTING, 0, NULL);
+  HANDLE proc, job;
+  DWORD err;
+  int rc = spawn(cwd, argv, env_add, (HANDLE)token, nul, wr, wr, &proc, &job,
+                 &err);
+  CloseHandle(wr);
+  if (nul != INVALID_HANDLE_VALUE)
+    CloseHandle(nul);
+  if (rc != 0) {
+    CloseHandle(rd);
+    if (err != ERROR_FILE_NOT_FOUND && err != ERROR_PATH_NOT_FOUND)
+      return -1;
+    cst_buf_t b = {0};
+    cst_buf_printf(&b, "%s: command not found\n", argv[0]);
+    r->out_len = b.len;
+    r->out = cst_buf_steal(&b);
+    r->exit_code = 127;
+    return 0;
+  }
+
+  size_t cap = 4096, len = 0;
+  char *buf = malloc(cap);
+  if (!buf) {
+    TerminateJobObject(job, 1);
+    TerminateProcess(proc, 1);
+    CloseHandle(rd);
+    CloseHandle(proc);
+    if (job)
+      CloseHandle(job);
+    return -1;
+  }
+  buf[0] = 0;
+  int truncated = 0, killed = 0, reaped = 0, bg_killed = 0;
+  double reaped_at = 0, killed_at = 0;
+  double deadline = os_now_ms() + os_run_timeout_effective() * 1000.0;
+  int idle = 0; /* empty polls in a row: wait longer once output stalls */
+  for (;;) {
+    DWORD avail = 0;
+    if (!PeekNamedPipe(rd, NULL, 0, NULL, &avail, NULL))
+      break; /* every writer closed */
+    if (avail) {
+      char tmp[65536];
+      DWORD n = 0;
+      if (!ReadFile(rd, tmp, avail < sizeof(tmp) ? avail : sizeof(tmp), &n,
+                    NULL) ||
+          n == 0)
+        break;
+      os_cap_append(&buf, &len, &cap, max_out, tmp, n, &truncated);
+      idle = 0;
+    } else if (reaped) {
+      Sleep(idle++ < 50 ? 1 : 20);
+    }
+    DWORD wait = avail ? 0 : idle++ < 50 ? 1 : 20;
+    if (!reaped && WaitForSingleObject(proc, wait) == WAIT_OBJECT_0) {
+      reaped = 1;
+      reaped_at = os_now_ms();
+    }
+    double now = os_now_ms();
+    /* The shell exited but a background child still holds the pipe
+     * (`server &`): give it a moment, then end the tree. */
+    if (reaped && !killed && !bg_killed && now - reaped_at > 1000) {
+      TerminateJobObject(job, 1);
+      bg_killed = 1;
+      killed_at = now;
+    }
+    if (!reaped && !killed && (os_cancel_requested() || now > deadline)) {
+      killed = os_cancel_requested() ? 2 : 1;
+      killed_at = now;
+      TerminateJobObject(job, killed == 1 ? 124 : 130);
+      if (!job)
+        TerminateProcess(proc, killed == 1 ? 124 : 130);
+    }
+    /* a writer outside the job can keep the pipe open */
+    if ((killed || bg_killed) && now - killed_at > 3000)
+      break;
+  }
+  CloseHandle(rd);
+  WaitForSingleObject(proc, killed ? 5000 : INFINITE);
+  DWORD code = 1;
+  GetExitCodeProcess(proc, &code);
+  if (!bg_killed && !killed && job_lingers(job))
+    bg_killed = 1; /* closing the job below ends them */
+  CloseHandle(proc);
+  if (job)
+    CloseHandle(job);
+
+  size_t ulen = 0;
+  char *u = os_output_to_utf8(buf, len, &ulen);
+  if (u) {
+    free(buf);
+    buf = u;
+    len = ulen;
+    cap = ulen + 1;
+  }
+  if (truncated)
+    os_cap_note(&buf, &len, &cap, "\n...(output truncated)\n");
+  if (bg_killed && !killed)
+    os_cap_note(&buf, &len, &cap,
+                "\n[cst: background processes left running were stopped]\n");
+  if (killed == 1) {
+    char note[96];
+    snprintf(note, sizeof(note), "\n[cst: killed after %ds timeout]\n",
+             os_run_timeout_effective());
+    os_cap_note(&buf, &len, &cap, note);
+    code = 124;
+  } else if (killed == 2) {
+    os_cap_note(&buf, &len, &cap, "\n[cst: cancelled]\n");
+    code = 130;
+  }
+  r->out = buf;
+  r->out_len = len;
+  r->exit_code = (int)code;
+  return 0;
+}
+
+int os_run_capture(const char *cwd, const char *const argv[], size_t max_out,
+                   os_run_result_t *r) {
+  return os_run_capture_token(cwd, argv, max_out, r, NULL, NULL);
+}
+
+int os_run_capture_ex(const char *cwd, const char *const argv[],
+                      size_t max_out, os_run_result_t *r,
+                      os_child_hook_fn child_hook, void *ud) {
+  (void)child_hook;
+  (void)ud;
+  return os_run_capture_token(cwd, argv, max_out, r, NULL, NULL);
+}
+
+int os_proc_spawn(const char *cwd, const char *const argv[],
+                  const char *const env_add[], const char *stderr_path,
+                  os_proc_t *p) {
+  memset(p, 0, sizeof(*p));
+  if (!argv || !argv[0])
+    return -1;
+  SECURITY_ATTRIBUTES sa = {sizeof(sa), NULL, TRUE};
+  HANDLE in_r = NULL, in_w = NULL, out_r = NULL, out_w = NULL;
+  if (!CreatePipe(&in_r, &in_w, &sa, 64 * 1024))
+    return -1;
+  if (!CreatePipe(&out_r, &out_w, &sa, 64 * 1024)) {
+    CloseHandle(in_r);
+    CloseHandle(in_w);
+    return -1;
+  }
+  SetHandleInformation(in_w, HANDLE_FLAG_INHERIT, 0);
+  SetHandleInformation(out_r, HANDLE_FLAG_INHERIT, 0);
+  wchar_t *werr = stderr_path ? wpath(stderr_path) : NULL;
+  HANDLE err = CreateFileW(werr ? werr : L"NUL", GENERIC_WRITE,
+                           FILE_SHARE_READ | FILE_SHARE_WRITE, &sa,
+                           werr ? CREATE_ALWAYS : OPEN_EXISTING, 0, NULL);
+  free(werr);
+  HANDLE proc, job;
+  DWORD e;
+  int rc = spawn(cwd, argv, env_add, NULL, in_r, out_w,
+                 err != INVALID_HANDLE_VALUE ? err : out_w, &proc, &job, &e);
+  CloseHandle(in_r);
+  CloseHandle(out_w);
+  if (err != INVALID_HANDLE_VALUE)
+    CloseHandle(err);
+  if (rc != 0) {
+    CloseHandle(in_w);
+    CloseHandle(out_r);
+    return -1;
+  }
+  p->proc = proc;
+  p->job = job;
+  p->in_w = in_w;
+  p->out_r = out_r;
+  return 0;
+}
+
+int os_proc_write(os_proc_t *p, const char *data, size_t n) {
+  while (n > 0) {
+    DWORD w = 0;
+    if (!p->in_w || !WriteFile((HANDLE)p->in_w, data, (DWORD)n, &w, NULL) ||
+        w == 0)
+      return -1;
+    data += w;
+    n -= w;
+  }
+  return 0;
+}
+
+long os_proc_read(os_proc_t *p, char *buf, size_t n, int timeout_ms) {
+  if (!p->out_r)
+    return -1;
+  double deadline = os_now_ms() + timeout_ms;
+  DWORD avail = 0;
+  for (;;) {
+    if (!PeekNamedPipe((HANDLE)p->out_r, NULL, 0, NULL, &avail, NULL))
+      return GetLastError() == ERROR_BROKEN_PIPE ? 0 : -1;
+    if (avail > 0)
+      break;
+    if (os_now_ms() >= deadline)
+      return -2;
+    Sleep(5);
+  }
+  DWORD r = 0;
+  if (!ReadFile((HANDLE)p->out_r, buf, avail < n ? avail : (DWORD)n, &r, NULL))
+    return GetLastError() == ERROR_BROKEN_PIPE ? 0 : -1;
+  return (long)r;
+}
+
+void os_proc_close_stdin(os_proc_t *p) {
+  if (p->in_w) {
+    CloseHandle((HANDLE)p->in_w);
+    p->in_w = NULL;
+  }
+}
+
+void os_proc_kill(os_proc_t *p) {
+  os_proc_close_stdin(p);
+  if (p->proc) {
+    /* polite first: most servers exit when stdin closes */
+    if (WaitForSingleObject((HANDLE)p->proc, 500) != WAIT_OBJECT_0) {
+      if (p->job)
+        TerminateJobObject((HANDLE)p->job, 1);
+      else
+        TerminateProcess((HANDLE)p->proc, 1);
+    }
+    WaitForSingleObject((HANDLE)p->proc, 2000);
+    CloseHandle((HANDLE)p->proc);
+    p->proc = NULL;
+  }
+  if (p->job) {
+    CloseHandle((HANDLE)p->job); /* ends anything the server left behind */
+    p->job = NULL;
+  }
+  if (p->out_r) {
+    CloseHandle((HANDLE)p->out_r);
+    p->out_r = NULL;
+  }
+}
+
+void os_windows_version(char *out, size_t n) {
+  typedef LONG(WINAPI * rtl_ver_fn)(OSVERSIONINFOW *);
+  OSVERSIONINFOW vi;
+  memset(&vi, 0, sizeof(vi));
+  vi.dwOSVersionInfoSize = sizeof(vi);
+  HMODULE nt = GetModuleHandleW(L"ntdll.dll");
+  rtl_ver_fn fn = nt ? (rtl_ver_fn)(void (*)(void))GetProcAddress(nt, "RtlGetVersion")
+                     : NULL;
+  SYSTEM_INFO si;
+  GetNativeSystemInfo(&si);
+  const char *arch = si.wProcessorArchitecture == PROCESSOR_ARCHITECTURE_ARM64
+                         ? "arm64"
+                         : "x86_64";
+  if (fn && fn(&vi) == 0)
+    snprintf(out, n, "Windows %lu.%lu.%lu %s", vi.dwMajorVersion,
+             vi.dwMinorVersion, vi.dwBuildNumber, arch);
+  else
+    snprintf(out, n, "Windows %s", arch);
+}
+
+/* Mandatory label from an SDDL SACL such as "S:(ML;;NWNR;;;ME)". */
+int os_win_set_label(const char *path, const char *sddl) {
+  wchar_t *wp = wpath(path), *ws = os_utf8_to_wide(sddl);
+  PSECURITY_DESCRIPTOR sd = NULL;
+  int rc = -1;
+  if (wp && ws &&
+      ConvertStringSecurityDescriptorToSecurityDescriptorW(ws, SDDL_REVISION_1,
+                                                           &sd, NULL)) {
+    PACL sacl = NULL;
+    BOOL present = FALSE, defaulted = FALSE;
+    if (GetSecurityDescriptorSacl(sd, &present, &sacl, &defaulted) && present &&
+        SetNamedSecurityInfoW(wp, SE_FILE_OBJECT, LABEL_SECURITY_INFORMATION,
+                              NULL, NULL, NULL, sacl) == ERROR_SUCCESS)
+      rc = 0;
+    LocalFree(sd);
+  }
+  free(wp);
+  free(ws);
+  return rc;
+}
+
+int os_win_get_label(const char *path, char *out, size_t n) {
+  wchar_t *wp = wpath(path);
+  PSECURITY_DESCRIPTOR sd = NULL;
+  wchar_t *ws = NULL;
+  int rc = -1;
+  if (wp && n > 2 &&
+      GetNamedSecurityInfoW(wp, SE_FILE_OBJECT, LABEL_SECURITY_INFORMATION,
+                            NULL, NULL, NULL, NULL, &sd) == ERROR_SUCCESS &&
+      ConvertSecurityDescriptorToStringSecurityDescriptorW(
+          sd, SDDL_REVISION_1, LABEL_SECURITY_INFORMATION, &ws, NULL)) {
+    char *s = os_wide_to_utf8(ws);
+    if (s) {
+      /* keep "S:" and the explicit ACEs; inherited ones carry the ID flag */
+      size_t o = 0;
+      out[o++] = 'S';
+      out[o++] = ':';
+      rc = 0;
+      for (const char *p = strchr(s, '('); p; p = strchr(p + 1, '(')) {
+        const char *e = strchr(p, ')');
+        if (!e)
+          break;
+        /* (type;flags;rights;...): flags are two-letter codes */
+        const char *f = strchr(p, ';');
+        int inherited = 0;
+        for (f = f && f < e ? f + 1 : e; f + 1 < e && *f != ';'; f += 2)
+          inherited |= f[0] == 'I' && f[1] == 'D';
+        size_t len = (size_t)(e - p) + 1;
+        if (inherited)
+          continue;
+        if (o + len >= n) {
+          rc = -1;
+          break;
+        }
+        memcpy(out + o, p, len);
+        o += len;
+      }
+      out[o] = 0;
+      free(s);
+    }
+  }
+  if (ws)
+    LocalFree(ws);
+  if (sd)
+    LocalFree(sd);
+  free(wp);
+  return rc;
+}
+
+int os_chmod_private(const char *path) {
+  if (!path)
+    return -1;
+  return os_win_set_label(path, "S:(ML;;NWNRNX;;;ME)");
+}
+
+/* --- clipboard ----------------------------------------------------------- */
+
+int os_clipboard_set(const char *utf8, size_t n) {
+  cst_buf_t b = {0}; /* CRLF is what Windows text consumers expect */
+  for (size_t i = 0; i < n; i++) {
+    if (utf8[i] == '\n' && (i == 0 || utf8[i - 1] != '\r'))
+      cst_buf_puts(&b, "\r");
+    cst_buf_append(&b, utf8 + i, 1);
+  }
+  if (!b.buf)
+    cst_buf_puts(&b, "");
+  int wn = MultiByteToWideChar(CP_UTF8, 0, b.buf, (int)b.len, NULL, 0);
+  HGLOBAL h = GlobalAlloc(GMEM_MOVEABLE, ((size_t)wn + 1) * sizeof(wchar_t));
+  wchar_t *w = h ? GlobalLock(h) : NULL;
+  if (!w) {
+    if (h)
+      GlobalFree(h);
+    cst_buf_free(&b);
+    return -1;
+  }
+  MultiByteToWideChar(CP_UTF8, 0, b.buf, (int)b.len, w, wn);
+  w[wn] = 0;
+  GlobalUnlock(h);
+  cst_buf_free(&b);
+  if (!OpenClipboard(NULL)) {
+    GlobalFree(h);
+    return -1;
+  }
+  EmptyClipboard();
+  int ok = SetClipboardData(CF_UNICODETEXT, h) != NULL;
+  if (!ok)
+    GlobalFree(h);
+  CloseClipboard();
+  return ok ? 0 : -1;
+}
+
+#endif /* _WIN32 */
diff --git a/src/permissions.c b/src/permissions.c
index 56acf03..e1f687d 100644
--- a/src/permissions.c
+++ b/src/permissions.c
@@ -7,6 +7,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
 
 #include "cJSON.h"
 #include "cst_perms.h"
@@ -33,7 +34,7 @@ static void load(cst_perms_t *p) {
   while ((n = fread(tmp, 1, sizeof(tmp), fp)) > 0 && b.len < 256 * 1024)
     cst_buf_append(&b, tmp, n);
   fclose(fp);
-  cJSON *root = b.buf ? cJSON_Parse(b.buf) : NULL;
+  cJSON *root = b.buf ? cJSON_Parse(b.buf + cst_bom_len(b.buf, b.len)) : NULL;
   cst_buf_free(&b);
   const cJSON *it = NULL;
   cJSON_ArrayForEach(it, cJSON_GetObjectItemCaseSensitive(root, "tools")) {
@@ -222,6 +223,73 @@ void cst_perms_suggest_prefix(const char *cmd, char *out, size_t out_sz) {
     out[0] = 0;
 }
 
+/* --- network commands ------------------------------------------------------ */
+
+static int net_word_eq(const char *w, size_t n, const char *name) {
+  size_t k = strlen(name);
+  if (n == k + 4 && strncasecmp(w + k, ".exe", 4) == 0)
+    n = k;
+  return n == k && strncasecmp(w, name, k) == 0;
+}
+
+int cst_shell_uses_network(const char *cmd) {
+  static const char *const TOOLS[] = {
+      "curl",   "wget",     "ssh",   "scp",     "sftp",    "rsync",
+      "ftp",    "tftp",     "telnet", "nc",     "ncat",    "netcat",
+      "socat",  "npx",      "invoke-webrequest", "iwr",    "invoke-restmethod",
+      "irm",    "start-bitstransfer", "bitsadmin", "certutil"};
+  /* tool + sub-command that downloads or uploads */
+  static const char *const PAIRS[][2] = {
+      {"git", "clone"},     {"git", "fetch"},     {"git", "pull"},
+      {"git", "push"},      {"git", "ls-remote"}, {"git", "submodule"},
+      {"npm", "install"},   {"npm", "i"},         {"npm", "ci"},
+      {"npm", "update"},    {"npm", "publish"},   {"npm", "exec"},
+      {"pnpm", "install"},  {"pnpm", "add"},      {"pnpm", "dlx"},
+      {"yarn", "install"},  {"yarn", "add"},      {"bun", "install"},
+      {"bun", "add"},       {"pip", "install"},   {"pip", "download"},
+      {"pip3", "install"},  {"uv", "pip"},        {"uv", "add"},
+      {"uv", "sync"},       {"cargo", "install"}, {"cargo", "fetch"},
+      {"cargo", "update"},  {"cargo", "publish"}, {"go", "get"},
+      {"go", "install"},    {"go", "mod"},        {"gem", "install"},
+      {"dotnet", "restore"}, {"dotnet", "add"},   {"winget", "install"},
+      {"choco", "install"}, {"scoop", "install"}, {"apt", "install"},
+      {"apt-get", "install"}, {"pkg", "install"}, {"brew", "install"}};
+  if (!cmd)
+    return 0;
+  const char *prev = NULL;
+  size_t prev_n = 0;
+  for (const char *p = cmd; *p;) {
+    while (*p && strchr(" \t\r\n;|&()<>`'\"$=", *p))
+      p++;
+    const char *w = p;
+    while (*p && !strchr(" \t\r\n;|&()<>`'\"$=", *p))
+      p++;
+    size_t n = (size_t)(p - w);
+    if (!n)
+      break;
+    /* /usr/bin/curl, C:\tools\curl.exe */
+    for (size_t i = n; i > 0; i--) {
+      if (w[i - 1] == '/' || w[i - 1] == '\\') {
+        n -= i;
+        w += i;
+        break;
+      }
+    }
+    for (size_t i = 0; i < sizeof(TOOLS) / sizeof(TOOLS[0]); i++)
+      if (net_word_eq(w, n, TOOLS[i]))
+        return 1;
+    for (size_t i = 0; prev && i < sizeof(PAIRS) / sizeof(PAIRS[0]); i++)
+      if (net_word_eq(prev, prev_n, PAIRS[i][0]) &&
+          net_word_eq(w, n, PAIRS[i][1]))
+        return 1;
+    if (n && w[0] != '-') {
+      prev = w;
+      prev_n = n;
+    }
+  }
+  return 0;
+}
+
 /* --- read-only command rules ---------------------------------------------- */
 
 #define SAFE_MAX_WORDS 64
diff --git a/src/plugins.c b/src/plugins.c
index f35a491..c999f0f 100644
--- a/src/plugins.c
+++ b/src/plugins.c
@@ -11,10 +11,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
-#ifndef _WIN32
-#include <dirent.h>
 #include <unistd.h>
-#endif
 
 #include "cJSON.h"
 #include "cst_mcp.h"
@@ -60,6 +57,7 @@ static char *slurp(const char *path, size_t max) {
   fclose(fp);
   if (!b.buf)
     cst_buf_puts(&b, "");
+  cst_strip_bom(b.buf, &b.len);
   return cst_buf_steal(&b);
 }
 
@@ -101,14 +99,6 @@ static int plugin_run(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
                       cst_tool_result_t *r, void *ud) {
   const ptool_t *pt = ud;
   r->exit_code = 1;
-#ifdef _WIN32
-  (void)ctx;
-  (void)c;
-  (void)pt;
-  r->out = strdup("error: plugin tools are not supported on Windows yet");
-  r->out_len = r->out ? strlen(r->out) : 0;
-  return 0;
-#else
   const cst_tool_def_t *def = cst_tool_find(pt->tool);
   char *args = cst_tool_args_json(def, c);
   char tmp[OS_PATH_MAX];
@@ -180,7 +170,6 @@ static int plugin_run(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
   r->out_len = out.len;
   r->out = cst_buf_steal(&out);
   return 0;
-#endif
 }
 
 /* argv array -> quoted command line; relative entries found in the plugin
@@ -339,21 +328,20 @@ static void load_plugin(const char *dir, const char *dirname,
 
 static int scan(const char *root, const char *source) {
   int n = 0;
-#ifndef _WIN32
-  DIR *d = opendir(root);
+  os_dir_t *d = os_dir_open(root);
   if (!d)
     return 0;
   char *names[CST_PLUGINS_MAX * 2];
   int nn = 0;
-  struct dirent *de;
-  while (nn < CST_PLUGINS_MAX * 2 && (de = readdir(d)) != NULL) {
-    if (de->d_name[0] == '.')
+  const os_dirent_t *de;
+  while (nn < CST_PLUGINS_MAX * 2 && (de = os_dir_next(d)) != NULL) {
+    if (de->name[0] == '.')
       continue;
-    names[nn] = strdup(de->d_name);
+    names[nn] = strdup(de->name);
     if (names[nn])
       nn++;
   }
-  closedir(d);
+  os_dir_close(d);
   for (int i = 1; i < nn; i++)
     for (int j = i; j > 0 && strcmp(names[j - 1], names[j]) > 0; j--) {
       char *t = names[j];
@@ -371,32 +359,24 @@ static int scan(const char *root, const char *source) {
     }
     free(names[i]);
   }
-#else
-  (void)root;
-  (void)source;
-#endif
   return n;
 }
 
 static int count_plugin_dirs(const char *root) {
   int n = 0;
-#ifndef _WIN32
-  DIR *d = opendir(root);
+  os_dir_t *d = os_dir_open(root);
   if (!d)
     return 0;
-  struct dirent *de;
-  while ((de = readdir(d)) != NULL) {
+  const os_dirent_t *de;
+  while ((de = os_dir_next(d)) != NULL) {
     char pj[OS_PATH_MAX];
-    if (de->d_name[0] != '.' &&
-        snprintf(pj, sizeof(pj), "%s/%s/plugin.json", root, de->d_name) <
+    if (de->name[0] != '.' &&
+        snprintf(pj, sizeof(pj), "%s/%s/plugin.json", root, de->name) <
             (int)sizeof(pj) &&
         is_file(pj))
       n++;
   }
-  closedir(d);
-#else
-  (void)root;
-#endif
+  os_dir_close(d);
   return n;
 }
 
diff --git a/src/sandbox_exec.c b/src/sandbox_exec.c
index 9a3d750..16b04e7 100644
--- a/src/sandbox_exec.c
+++ b/src/sandbox_exec.c
@@ -19,6 +19,9 @@
 #elif defined(__APPLE__)
 #define CST_HAVE_SEATBELT 1
 #include <stdint.h>
+#elif defined(_WIN32)
+#include <windows.h>
+#include <sddl.h>
 #endif
 
 #if defined(__linux__) && (defined(__x86_64__) || defined(__aarch64__))
@@ -864,6 +867,341 @@ static int sc_probe(void) {
 
 #endif /* CST_HAVE_SECCOMP */
 
+/* --- Windows: Low integrity level ----------------------------------------- */
+#ifdef _WIN32
+
+#define LW_LABEL "S:(ML;OICI;NW;;;LW)"
+#define LW_RECORD "sandbox-labels"
+
+/* Same user, no admin privileges, Low IL. No LUA_TOKEN: a deny-only
+ * Administrators group cannot open an admin's (SSH) window station and the
+ * child fails in DLL init; the integrity check does not need it. */
+static HANDLE lw_token(void) {
+  HANDLE self = NULL, tok = NULL;
+  if (!OpenProcessToken(GetCurrentProcess(),
+                        TOKEN_DUPLICATE | TOKEN_QUERY | TOKEN_ADJUST_DEFAULT |
+                            TOKEN_ASSIGN_PRIMARY,
+                        &self))
+    return NULL;
+  BOOL ok = CreateRestrictedToken(self, DISABLE_MAX_PRIVILEGE, 0, NULL, 0,
+                                  NULL, 0, NULL, &tok);
+  CloseHandle(self);
+  if (!ok)
+    return NULL;
+  PSID low = NULL;
+  if (!ConvertStringSidToSidW(L"S-1-16-4096", &low)) {
+    CloseHandle(tok);
+    return NULL;
+  }
+  TOKEN_MANDATORY_LABEL tml;
+  memset(&tml, 0, sizeof(tml));
+  tml.Label.Sid = low;
+  tml.Label.Attributes = SE_GROUP_INTEGRITY;
+  ok = SetTokenInformation(tok, TokenIntegrityLevel, &tml,
+                           (DWORD)(sizeof(tml) + GetLengthSid(low)));
+  LocalFree(low);
+  if (!ok) {
+    CloseHandle(tok);
+    return NULL;
+  }
+  return tok;
+}
+
+static int lw_record_path(char *out, size_t n) {
+  char dir[OS_PATH_MAX];
+  if (os_config_dir(dir, sizeof(dir)) != 0)
+    return -1;
+  return snprintf(out, n, "%s/%s", dir, LW_RECORD) < (int)n ? 0 : -1;
+}
+
+static char *lw_read_record(void) {
+  char path[OS_PATH_MAX];
+  if (lw_record_path(path, sizeof(path)) != 0)
+    return NULL;
+  FILE *f = fopen(path, "rb");
+  if (!f)
+    return NULL;
+  size_t cap = 4096, len = 0;
+  char *s = malloc(cap);
+  size_t k;
+  while (s && (k = fread(s + len, 1, cap - len - 1, f)) > 0) {
+    len += k;
+    if (cap - len < 2) {
+      char *g = realloc(s, cap * 2);
+      if (!g) {
+        free(s);
+        s = NULL;
+        break;
+      }
+      s = g;
+      cap *= 2;
+    }
+  }
+  fclose(f);
+  if (s)
+    s[len] = 0;
+  return s;
+}
+
+/* dir is a recorded directory or inside one (the label is inherited). */
+static int lw_recorded(const char *dir) {
+  char *s = lw_read_record();
+  int found = 0;
+  for (char *line = s; line && *line && !found;) {
+    char *nl = strchr(line, '\n');
+    if (nl)
+      *nl = 0;
+    char *tab = strchr(line, '\t');
+    if (tab)
+      *tab = 0;
+    found = line[0] && os_path_under(line, dir);
+    line = nl ? nl + 1 : NULL;
+  }
+  free(s);
+  return found;
+}
+
+static int lw_record_add(const char *dir, const char *old_sddl) {
+  char path[OS_PATH_MAX];
+  if (lw_record_path(path, sizeof(path)) != 0)
+    return -1;
+  FILE *f = fopen(path, "ab");
+  if (!f)
+    return -1;
+  fprintf(f, "%s\t%s\n", dir, old_sddl);
+  return fclose(f) == 0 ? 0 : -1;
+}
+
+static int lw_same_dir(const char *a, const char *b) {
+  return a && b && a[0] && b[0] && os_path_under(a, b) && os_path_under(b, a);
+}
+
+/* An environment directory in the form os_realpath gives the workspace
+ * (long names, '/'), or NULL. */
+static const char *lw_env_dir(const char *name, char *buf, size_t n) {
+  const char *v = getenv(name);
+  if (!v || !v[0] || os_realpath(v, buf, n) != 0)
+    return NULL;
+  os_path_norm_slashes(buf);
+  return buf;
+}
+
+/* Labeling a whole drive, the profile or system folders would open far more
+ * than a project to every sandboxed command. */
+static int lw_refused(const char *dir) {
+  size_t n = strlen(dir);
+  while (n > 0 && (dir[n - 1] == '/' || dir[n - 1] == '\\'))
+    n--;
+  if (n <= 2)
+    return 1;
+  static const char *const SELF[] = {"USERPROFILE", "APPDATA",
+                                     "LOCALAPPDATA", "TEMP"};
+  static const char *const TREE[] = {"SystemRoot", "ProgramFiles",
+                                     "ProgramFiles(x86)", "ProgramData"};
+  char buf[OS_PATH_MAX];
+  for (size_t i = 0; i < sizeof(SELF) / sizeof(SELF[0]); i++)
+    if (lw_same_dir(lw_env_dir(SELF[i], buf, sizeof(buf)), dir))
+      return 1;
+  for (size_t i = 0; i < sizeof(TREE) / sizeof(TREE[0]); i++) {
+    const char *v = lw_env_dir(TREE[i], buf, sizeof(buf));
+    if (v && os_path_under(v, dir))
+      return 1;
+  }
+  return 0;
+}
+
+static int lw_prepare(const char *ws, cst_sandbox_plan_t *p) {
+  static int creds_done, tmp_done;
+  char buf[OS_PATH_MAX + 256];
+  if (!ws || !ws[0])
+    return -1;
+  if (!creds_done) {
+    /* files saved by older versions have no no-read-up label yet */
+    char dir[OS_PATH_MAX];
+    if (os_config_dir(dir, sizeof(dir)) == 0 &&
+        snprintf(buf, sizeof(buf), "%s/credentials", dir) < (int)sizeof(buf)) {
+      os_stat_t st;
+      if (os_lstat(buf, &st) != 0 || os_chmod_private(buf) == 0)
+        creds_done = 1;
+    }
+  }
+  char tmp[OS_PATH_MAX];
+  if (os_temp_dir(tmp, sizeof(tmp)) != 0 ||
+      snprintf(buf, sizeof(buf), "%s/cst-agent-sandbox", tmp) >=
+          (int)sizeof(tmp))
+    return -1;
+  memcpy(tmp, buf, strlen(buf) + 1);
+  if (!tmp_done) {
+    os_mkdir_p(tmp, 0700);
+    if (os_win_set_label(tmp, LW_LABEL) != 0)
+      return -1;
+    tmp_done = 1;
+  }
+  if (!lw_recorded(ws)) {
+    char old[512];
+    if (lw_refused(ws) || os_win_get_label(ws, old, sizeof(old)) != 0 ||
+        os_win_set_label(ws, LW_LABEL) != 0)
+      return -1;
+    lw_record_add(ws, old);
+    snprintf(buf, sizeof(buf),
+             "[cst: sandbox: labeled %s Low integrity so sandboxed commands "
+             "can write there; /sandbox reset-labels undoes it]\n",
+             ws);
+    p->note = strdup(buf);
+  }
+  HANDLE tok = lw_token();
+  if (!tok) {
+    free(p->note);
+    p->note = NULL;
+    return -1;
+  }
+  p->token = tok;
+  for (char *c = tmp; *c; c++)
+    if (*c == '/')
+      *c = '\\';
+  p->tmpdir = strdup(tmp);
+  return p->tmpdir ? 0 : -1;
+}
+
+static int lw_run(const char *ws, const char *cmd, size_t max_out,
+                  const cst_sandbox_plan_t *p, os_run_result_t *r) {
+  size_t tl = strlen(p->tmpdir) + 8;
+  char *te = malloc(tl), *tm = malloc(tl);
+  int rc = -1;
+  if (te && tm) {
+    snprintf(te, tl, "TEMP=%s", p->tmpdir);
+    snprintf(tm, tl, "TMP=%s", p->tmpdir);
+    const char *env[] = {te, tm, NULL};
+    rc = os_run_shell_token(ws, cmd, max_out, r, p->token, env);
+  }
+  free(te);
+  free(tm);
+  if (rc == 0 && p->note) {
+    size_t nl = strlen(p->note);
+    char *o = malloc(nl + r->out_len + 1);
+    if (o) {
+      memcpy(o, p->note, nl);
+      if (r->out)
+        memcpy(o + nl, r->out, r->out_len);
+      o[nl + r->out_len] = 0;
+      free(r->out);
+      r->out = o;
+      r->out_len += nl;
+    }
+  }
+  return rc;
+}
+
+#endif /* _WIN32 */
+
+char *cst_sandbox_labels(void) {
+#ifdef _WIN32
+  char *s = lw_read_record();
+  if (!s)
+    return NULL;
+  size_t o = 0;
+  for (char *line = s; *line;) {
+    char *nl = strchr(line, '\n');
+    size_t len = nl ? (size_t)(nl - line) : strlen(line);
+    size_t path = strcspn(line, "\t\n");
+    if (path) {
+      memmove(s + o, line, path);
+      o += path;
+      s[o++] = '\n';
+    }
+    line += len + (nl ? 1 : 0);
+  }
+  s[o] = 0;
+  if (!o) {
+    free(s);
+    return NULL;
+  }
+  return s;
+#else
+  return NULL;
+#endif
+}
+
+int cst_sandbox_reset_labels(char **report) {
+  if (report)
+    *report = NULL;
+#ifdef _WIN32
+  char *s = lw_read_record();
+  size_t cap = 256, len = 0;
+  char *rep = malloc(cap), *keep = NULL;
+  size_t kcap = 0, klen = 0;
+  int ok = 0, bad = 0;
+  if (rep)
+    rep[0] = 0;
+  for (char *line = s; line && *line;) {
+    char *nl = strchr(line, '\n');
+    if (nl)
+      *nl = 0;
+    char *tab = strchr(line, '\t');
+    const char *old = tab ? tab + 1 : "S:";
+    if (tab)
+      *tab = 0;
+    if (line[0]) {
+      os_stat_t st;
+      int gone = os_lstat(line, &st) != 0;
+      int done = gone || os_win_set_label(line, old[0] ? old : "S:") == 0;
+      char msg[OS_PATH_MAX + 64];
+      int m = snprintf(msg, sizeof(msg), "%s %s\n",
+                       gone ? "gone    " : done ? "restored" : "FAILED  ",
+                       line);
+      if (m > 0 && rep) {
+        while (len + (size_t)m + 1 > cap) {
+          char *g = realloc(rep, cap *= 2);
+          if (!g)
+            break;
+          rep = g;
+        }
+        if (len + (size_t)m + 1 <= cap) {
+          memcpy(rep + len, msg, (size_t)m + 1);
+          len += (size_t)m;
+        }
+      }
+      if (done) {
+        ok++;
+      } else {
+        bad++;
+        size_t need = strlen(line) + strlen(old) + 3;
+        if (klen + need + 1 > kcap) {
+          char *g = realloc(keep, kcap = (klen + need + 1) * 2);
+          if (g)
+            keep = g;
+        }
+        if (keep && klen + need + 1 <= kcap)
+          klen += (size_t)snprintf(keep + klen, kcap - klen, "%s\t%s\n",
+                                   line, old);
+      }
+    }
+    line = nl ? nl + 1 : NULL;
+  }
+  free(s);
+  char path[OS_PATH_MAX];
+  if (lw_record_path(path, sizeof(path)) == 0) {
+    if (klen) {
+      FILE *f = fopen(path, "wb");
+      if (f) {
+        fwrite(keep, 1, klen, f);
+        fclose(f);
+      }
+    } else {
+      remove(path);
+    }
+  }
+  free(keep);
+  if (report)
+    *report = rep;
+  else
+    free(rep);
+  return bad ? -1 : ok;
+#else
+  return 0;
+#endif
+}
+
 /* --- common --------------------------------------------------------------- */
 
 int cst_sandbox_probe(void) {
@@ -891,6 +1229,15 @@ int cst_sandbox_probe(void) {
 #endif
 #ifdef CST_HAVE_SEATBELT
   kind = CST_SANDBOX_SEATBELT;
+#endif
+#ifdef _WIN32
+  if (!e || strcmp(e, "lowil") == 0) {
+    HANDLE tok = lw_token();
+    if (tok) {
+      CloseHandle(tok);
+      kind = CST_SANDBOX_LOWIL;
+    }
+  }
 #endif
   (void)want_ll;
   (void)want_sc;
@@ -917,6 +1264,8 @@ const char *cst_sandbox_name(int kind) {
     return "seatbelt";
   case CST_SANDBOX_SECCOMP:
     return "seccomp";
+  case CST_SANDBOX_LOWIL:
+    return "lowil";
   default:
     return "none";
   }
@@ -939,6 +1288,10 @@ int cst_sandbox_prepare(const char *workspace, const char *tmpdir,
 #ifdef CST_HAVE_SECCOMP
   if (kind == CST_SANDBOX_SECCOMP)
     rc = sc_prepare(workspace, tmpdir, plan);
+#endif
+#ifdef _WIN32
+  if (kind == CST_SANDBOX_LOWIL && (rc = lw_prepare(workspace, plan)) != 0)
+    cst_sandbox_release(plan);
 #endif
   (void)workspace;
   (void)tmpdir;
@@ -988,6 +1341,15 @@ void cst_sandbox_release(cst_sandbox_plan_t *plan) {
 #ifdef CST_HAVE_SECCOMP
   sc_free(plan->sc);
 #endif
+#ifdef _WIN32
+  if (plan->token)
+    CloseHandle(plan->token);
+#endif
+  plan->token = NULL;
+  free(plan->tmpdir);
+  plan->tmpdir = NULL;
+  free(plan->note);
+  plan->note = NULL;
   plan->sc = NULL;
   free(plan->profile);
   plan->profile = NULL;
@@ -1004,6 +1366,12 @@ int cst_sandbox_run_shell(const char *workspace, const char *cmd,
   if (cst_sandbox_prepare(workspace, tmp, &plan) != 0) {
     memset(r, 0, sizeof(*r));
     const char *msg = "[cst: sandbox unavailable; command not run]\n";
+#ifdef _WIN32
+    if (workspace && !lw_recorded(workspace) && lw_refused(workspace))
+      msg = "[cst: sandbox: will not label a drive root, the profile or a "
+            "system folder writable; command not run. Start cst-agent in a "
+            "project folder]\n";
+#endif
     r->out = malloc(strlen(msg) + 1);
     if (r->out) {
       memcpy(r->out, msg, strlen(msg) + 1);
@@ -1012,8 +1380,12 @@ int cst_sandbox_run_shell(const char *workspace, const char *cmd,
     r->exit_code = 126;
     return 0;
   }
+#ifdef _WIN32
+  int rc = lw_run(workspace, cmd, max_out, &plan, r);
+#else
   int rc = os_run_shell_ex(workspace, cmd, max_out, r, cst_sandbox_enter,
                            &plan);
+#endif
   cst_sandbox_release(&plan);
   return rc;
 }
@@ -1039,6 +1411,11 @@ int cst_sandbox_blocked(const char *out, size_t n, int exit_code) {
       "权限不够", "不允许的操作", "只读文件系统", "權限不足",
       "拒絕不符權限的操作", "許可がありません", "Keine Berechtigung",
       "Permission non accord", "Permiso denegado", "Отказано в доступе",
+      /* Windows ERROR_ACCESS_DENIED from cmd, PowerShell and Win32 tools */
+      "Access is denied", "Access to the path", "UnauthorizedAccess",
+      "拒绝访问", "存取被拒", "Zugriff verweigert", "Accès refusé",
+      /* Cygwin/MSYS2 programs cannot initialize at Low IL */
+      "DLL initialization routine failed", "0xc0000142",
   };
   for (size_t i = 0; i < sizeof(SIGNS) / sizeof(SIGNS[0]); i++)
     if (has(out, n, SIGNS[i]))
diff --git a/src/session.c b/src/session.c
index 041bb8c..39491c1 100644
--- a/src/session.c
+++ b/src/session.c
@@ -137,7 +137,7 @@ static const char *jstr(const cJSON *o, const char *key) {
 }
 
 static void load_existing(cst_session_t *s) {
-  FILE *rp = fopen(s->path, "r");
+  FILE *rp = fopen(s->path, "rb");
   if (!rp)
     return;
   char *line = NULL;
@@ -196,7 +196,7 @@ cst_session_t *cst_session_open(const char *path) {
   pthread_mutex_init(&s->mu, NULL);
   snprintf(s->path, sizeof(s->path), "%s", path ? path : "session.jsonl");
   load_existing(s);
-  s->fp = fopen(s->path, "a+");
+  s->fp = fopen(s->path, "a+b");
   if (!s->fp || session_grow(s) != 0) {
     if (s->fp)
       fclose(s->fp);
@@ -295,7 +295,7 @@ static int reopen_truncate(cst_session_t *s) {
     fclose(s->fp);
     s->fp = NULL;
   }
-  s->fp = fopen(s->path, "w+");
+  s->fp = fopen(s->path, "w+b");
   return s->fp ? 0 : -1;
 }
 
diff --git a/src/settings.c b/src/settings.c
index 2f5aada..c3ae64c 100644
--- a/src/settings.c
+++ b/src/settings.c
@@ -1,4 +1,5 @@
 #include "cst_agent.h"
+#include "cst_util.h"
 #include "os_compat.h"
 
 #include "cJSON.h"
@@ -31,7 +32,7 @@ int cst_settings_load(cst_settings_t *s) {
   size_t n = fread(buf, 1, sizeof(buf) - 1, fp);
   fclose(fp);
   buf[n] = 0;
-  cJSON *root = cJSON_Parse(buf);
+  cJSON *root = cJSON_Parse(buf + cst_bom_len(buf, n));
   if (!cJSON_IsObject(root)) {
     cJSON_Delete(root);
     return -1;
diff --git a/src/skills.c b/src/skills.c
index b6438d1..d246aff 100644
--- a/src/skills.c
+++ b/src/skills.c
@@ -13,10 +13,7 @@
 #include <string.h>
 #include <sys/stat.h>
 
-#ifndef _WIN32
-#include <dirent.h>
 #include <pthread.h>
-#endif
 
 #include "cst_tools.h"
 #include "cst_util.h"
@@ -166,14 +163,9 @@ static struct {
   char source[48];
 } g_roots[EXTRA_ROOTS];
 static int g_nroots;
-#ifndef _WIN32
 static pthread_mutex_t g_mu = PTHREAD_MUTEX_INITIALIZER;
 #define LOCK() pthread_mutex_lock(&g_mu)
 #define UNLOCK() pthread_mutex_unlock(&g_mu)
-#else
-#define LOCK() ((void)0)
-#define UNLOCK() ((void)0)
-#endif
 
 void cst_skills_add_root(const char *dir, const char *source) {
   if (!dir || !dir[0])
@@ -225,6 +217,7 @@ static char *slurp(const char *path, size_t max, size_t *len) {
   }
   if (!b.buf)
     cst_buf_puts(&b, "");
+  cst_strip_bom(b.buf, &b.len);
   if (len)
     *len = b.len;
   return cst_buf_steal(&b);
@@ -243,16 +236,15 @@ static int have(const cst_skill_t *v, int n, const char *name) {
 
 static int scan_root(const char *root, const char *source, cst_skill_t *out,
                      int n, int max) {
-#ifndef _WIN32
-  DIR *d = opendir(root);
+  os_dir_t *d = os_dir_open(root);
   if (!d)
     return n;
-  struct dirent *de;
-  while (n < max && (de = readdir(d)) != NULL) {
-    if (de->d_name[0] == '.')
+  const os_dirent_t *de;
+  while (n < max && (de = os_dir_next(d)) != NULL) {
+    if (de->name[0] == '.')
       continue;
     char dir[OS_PATH_MAX], md[OS_PATH_MAX + 16];
-    if (snprintf(dir, sizeof(dir), "%s/%s", root, de->d_name) >=
+    if (snprintf(dir, sizeof(dir), "%s/%s", root, de->name) >=
         (int)sizeof(dir))
       continue;
     snprintf(md, sizeof(md), "%s/SKILL.md", dir);
@@ -262,7 +254,7 @@ static int scan_root(const char *root, const char *source, cst_skill_t *out,
     cst_skill_t s;
     memset(&s, 0, sizeof(s));
     if (!cst_fm_get(text, "name", s.name, sizeof(s.name)) || !s.name[0])
-      snprintf(s.name, sizeof(s.name), "%.63s", de->d_name);
+      snprintf(s.name, sizeof(s.name), "%.63s", de->name);
     cst_fm_get(text, "description", s.desc, sizeof(s.desc));
     if (!s.desc[0]) {
       /* first prose line of the body */
@@ -282,13 +274,7 @@ static int scan_root(const char *root, const char *source, cst_skill_t *out,
     if (!have(out, n, s.name))
       out[n++] = s;
   }
-  closedir(d);
-#else
-  (void)root;
-  (void)source;
-  (void)out;
-  (void)max;
-#endif
+  os_dir_close(d);
   return n;
 }
 
@@ -371,25 +357,24 @@ static int find_skill(const char *ws, const char *name, cst_skill_t *out) {
 
 static void list_files(const char *dir, const char *rel, int depth,
                        cst_buf_t *b, int *count) {
-#ifndef _WIN32
   char full[OS_PATH_MAX];
   if (snprintf(full, sizeof(full), "%s%s%s", dir, rel[0] ? "/" : "", rel) >=
       (int)sizeof(full))
     return;
-  DIR *d = opendir(full);
+  os_dir_t *d = os_dir_open(full);
   if (!d)
     return;
   char *names[256];
   int nn = 0;
-  struct dirent *de;
-  while (nn < 256 && (de = readdir(d)) != NULL) {
-    if (de->d_name[0] == '.')
+  const os_dirent_t *de;
+  while (nn < 256 && (de = os_dir_next(d)) != NULL) {
+    if (de->name[0] == '.')
       continue;
-    names[nn] = strdup(de->d_name);
+    names[nn] = strdup(de->name);
     if (names[nn])
       nn++;
   }
-  closedir(d);
+  os_dir_close(d);
   for (int i = 1; i < nn; i++) {
     for (int j = i; j > 0 && strcmp(names[j - 1], names[j]) > 0; j--) {
       char *tmp = names[j];
@@ -416,13 +401,6 @@ static void list_files(const char *dir, const char *rel, int depth,
   }
   for (int i = 0; i < nn; i++)
     free(names[i]);
-#else
-  (void)dir;
-  (void)rel;
-  (void)depth;
-  (void)b;
-  (void)count;
-#endif
 }
 
 static char *errf(int *code, const char *fmt, const char *a, const char *b) {
diff --git a/src/subagent.c b/src/subagent.c
index 8fd2e57..32c489e 100644
--- a/src/subagent.c
+++ b/src/subagent.c
@@ -14,9 +14,6 @@
 #include <string.h>
 #include <sys/stat.h>
 #include <time.h>
-#ifndef _WIN32
-#include <dirent.h>
-#endif
 
 #include "cJSON.h"
 #include "cst_agent.h"
@@ -79,6 +76,7 @@ static char *slurp(const char *path, size_t max) {
   fclose(fp);
   if (!b.buf)
     cst_buf_puts(&b, "");
+  cst_strip_bom(b.buf, &b.len);
   return cst_buf_steal(&b);
 }
 
@@ -118,25 +116,24 @@ static int truthy(const char *v) {
 
 static void load_dir(const char *dir, const char *source, cst_agent_role_t *v,
                      int *n, int max) {
-#ifndef _WIN32
-  DIR *d = opendir(dir);
+  os_dir_t *d = os_dir_open(dir);
   if (!d)
     return;
-  struct dirent *de;
-  while ((de = readdir(d)) != NULL && *n < max) {
-    size_t len = strlen(de->d_name);
-    if (de->d_name[0] == '.' || len < 4 ||
-        strcmp(de->d_name + len - 3, ".md") != 0)
+  const os_dirent_t *de;
+  while ((de = os_dir_next(d)) != NULL && *n < max) {
+    size_t len = strlen(de->name);
+    if (de->name[0] == '.' || len < 4 ||
+        strcmp(de->name + len - 3, ".md") != 0)
       continue;
     char p[OS_PATH_MAX];
-    if (snprintf(p, sizeof(p), "%s/%s", dir, de->d_name) >= (int)sizeof(p))
+    if (snprintf(p, sizeof(p), "%s/%s", dir, de->name) >= (int)sizeof(p))
       continue;
     char *text = slurp(p, ROLE_FILE_MAX);
     if (!text)
       continue;
     char name[64], val[1024];
     if (!cst_fm_get(text, "name", name, sizeof(name)) || !name[0])
-      snprintf(name, sizeof(name), "%.*s", (int)(len - 3), de->d_name);
+      snprintf(name, sizeof(name), "%.*s", (int)(len - 3), de->name);
     char clean[64];
     cst_tool_sanitize_name(name, clean, sizeof(clean));
     int at = find_role(v, *n, clean);
@@ -166,14 +163,7 @@ static void load_dir(const char *dir, const char *source, cst_agent_role_t *v,
     r->prompt = strdup(body);
     free(text);
   }
-  closedir(d);
-#else
-  (void)dir;
-  (void)source;
-  (void)v;
-  (void)n;
-  (void)max;
-#endif
+  os_dir_close(d);
 }
 
 int cst_roles_list(const char *ws, cst_agent_role_t *out, int max) {
@@ -255,18 +245,16 @@ int cst_subagent_path(const char *ws, const char *parent_id, const char *file,
 static int next_file(const char *dir, char *file, size_t fsz) {
   pthread_mutex_lock(&g_seq_mu);
   int best = 0;
-#ifndef _WIN32
-  DIR *d = opendir(dir);
+  os_dir_t *d = os_dir_open(dir);
   if (d) {
-    struct dirent *de;
-    while ((de = readdir(d)) != NULL) {
+    const os_dirent_t *de;
+    while ((de = os_dir_next(d)) != NULL) {
       int k = 0;
-      if (sscanf(de->d_name, "sub-%d.jsonl", &k) == 1 && k > best)
+      if (sscanf(de->name, "sub-%d.jsonl", &k) == 1 && k > best)
         best = k;
     }
-    closedir(d);
+    os_dir_close(d);
   }
-#endif
   int rc = -1;
   for (int k = best + 1; k < best + 100; k++) {
     char p[OS_PATH_MAX];
@@ -276,7 +264,7 @@ static int next_file(const char *dir, char *file, size_t fsz) {
     struct stat st;
     if (stat(p, &st) == 0)
       continue;
-    FILE *fp = fopen(p, "a");
+    FILE *fp = fopen(p, "ab");
     if (fp) {
       fclose(fp);
       rc = 0;
@@ -302,7 +290,7 @@ static void write_meta(const char *dir, const char *file, const char *role,
   cJSON_AddNumberToObject(o, "ms", ms);
   char *txt = cJSON_PrintUnformatted(o);
   cJSON_Delete(o);
-  FILE *fp = txt ? fopen(p, "w") : NULL;
+  FILE *fp = txt ? fopen(p, "wb") : NULL;
   if (fp) {
     fputs(txt, fp);
     fputc('\n', fp);
@@ -317,19 +305,18 @@ int cst_subagent_list(const char *ws, const char *parent_id,
   if (sub_dir(ws, parent_id, dir, sizeof(dir)) != 0)
     return 0;
   int n = 0;
-#ifndef _WIN32
-  DIR *d = opendir(dir);
+  os_dir_t *d = os_dir_open(dir);
   if (!d)
     return 0;
-  struct dirent *de;
-  while ((de = readdir(d)) != NULL && n < max) {
+  const os_dirent_t *de;
+  while ((de = os_dir_next(d)) != NULL && n < max) {
     int k = 0;
     char tail[8] = "";
-    if (sscanf(de->d_name, "sub-%d.%7s", &k, tail) != 2 ||
+    if (sscanf(de->name, "sub-%d.%7s", &k, tail) != 2 ||
         strcmp(tail, "json") != 0)
       continue;
     char p[OS_PATH_MAX];
-    if (snprintf(p, sizeof(p), "%s/%s", dir, de->d_name) >= (int)sizeof(p))
+    if (snprintf(p, sizeof(p), "%s/%s", dir, de->name) >= (int)sizeof(p))
       continue;
     char *txt = slurp(p, 64 * 1024);
     cJSON *o = txt ? cJSON_Parse(txt) : NULL;
@@ -358,11 +345,7 @@ int cst_subagent_list(const char *ws, const char *parent_id,
       r->mtime = (long long)st.st_mtime;
     n++;
   }
-  closedir(d);
-#else
-  (void)out;
-  (void)max;
-#endif
+  os_dir_close(d);
   /* newest first: higher number */
   for (int i = 1; i < n; i++)
     for (int j = i; j > 0 && atoi(out[j - 1].file + 4) < atoi(out[j].file + 4);
diff --git a/src/tools/fs_tools.c b/src/tools/fs_tools.c
index 8189329..e28ab86 100644
--- a/src/tools/fs_tools.c
+++ b/src/tools/fs_tools.c
@@ -12,12 +12,7 @@
 #include <string.h>
 #include <sys/stat.h>
 
-#ifndef _WIN32
-#include <dirent.h>
-#include <fnmatch.h>
 #include <regex.h>
-#include <unistd.h>
-#endif
 
 #include "cst_tools.h"
 #include "cst_util.h"
@@ -154,6 +149,9 @@ int cst_tool_read_file2(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
   FILE *fp = fopen(full, "rb");
   if (!fp)
     return tool_set_resultf(r, 1, "error: cannot open file: %.200s", path);
+  char bom[3];
+  if (fread(bom, 1, 3, fp) != 3 || !cst_bom_len(bom, 3))
+    rewind(fp);
 
   long offset = tool_arg_long(c, "offset", 0);
   long limit = tool_arg_long(c, "limit", 0);
@@ -178,6 +176,8 @@ int cst_tool_read_file2(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
       return tool_set_resultf(r, 1, "error: %.200s is a binary file (%zu bytes)",
                               path, n);
     }
+    cst_strip_bom(buf, &n);
+    n = cst_crlf_to_lf(buf, n); /* edits match LF text and keep CRLF */
     cst_tool_result_free(r);
     r->out = buf;
     r->out_len = n;
@@ -217,6 +217,9 @@ int cst_tool_read_file2(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
     }
     if (numbers)
       cst_buf_printf(&b, "%6ld|", lineno);
+    if (line.len >= 2 && line.buf[line.len - 2] == '\r' &&
+        line.buf[line.len - 1] == '\n')
+      line.buf[--line.len - 1] = '\n';
     cst_buf_append(&b, line.buf, line.len);
     shown++;
   }
@@ -442,6 +445,14 @@ static int plan_edit(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
         nwn = n2n;
       }
     }
+  } else if (cnt && memchr(nw, '\n', nwn) &&
+             cst_text_is_crlf(pl->oldc, pl->olen)) {
+    size_t n2n;
+    n2 = to_crlf(nw, nwn, &n2n);
+    if (n2) {
+      nw = n2;
+      nwn = n2n;
+    }
   }
   int rc = 0;
   if (cnt == 0) {
@@ -539,7 +550,6 @@ int cst_preview_edit_file(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
 /* --- delete_file / move_file --------------------------------------------- */
 
 static int reject_symlink(const cst_tool_ctx_t *ctx, const char *path) {
-#ifndef _WIN32
   char root[OS_PATH_MAX], joined[OS_PATH_MAX];
   if (os_realpath(ctx->workspace_root, root, sizeof(root)) != 0)
     return 1;
@@ -547,13 +557,9 @@ static int reject_symlink(const cst_tool_ctx_t *ctx, const char *path) {
     snprintf(joined, sizeof(joined), "%s", path);
   else if (os_path_join(joined, sizeof(joined), root, path) != 0)
     return 1;
-  struct stat st;
-  if (lstat(joined, &st) == 0 && S_ISLNK(st.st_mode))
+  os_stat_t st;
+  if (os_lstat(joined, &st) == 0 && st.is_link)
     return 1;
-#else
-  (void)ctx;
-  (void)path;
-#endif
   return 0;
 }
 
@@ -672,8 +678,6 @@ int cst_tool_move_file(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
 
 /* --- directory walking (list_dir / glob / grep) -------------------------- */
 
-#ifndef _WIN32
-
 static const char *const SKIP_DIRS[] = {
     ".git", ".hg", ".svn", "node_modules", ".agent", "__pycache__",
     ".venv", ".cache", ".idea", ".vscode", ".mypy_cache", ".pytest_cache"};
@@ -703,7 +707,7 @@ static void ignore_load(const char *root, ignore_t *ig) {
   char p[OS_PATH_MAX];
   if (os_path_join(p, sizeof(p), root, ".gitignore") != 0)
     return;
-  FILE *fp = fopen(p, "r");
+  FILE *fp = fopen(p, "rb");
   if (!fp)
     return;
   char line[512];
@@ -749,7 +753,7 @@ static int ignored(const ignore_t *ig, const char *rel, const char *name,
     const ign_rule_t *r = &ig->v[i];
     if (r->dir_only && !isdir)
       continue;
-    if (fnmatch(r->pat, r->anchored ? rel : name, 0) == 0)
+    if (cst_fnmatch(r->pat, r->anchored ? rel : name, 0) == 0)
       return 1;
   }
   return 0;
@@ -758,7 +762,7 @@ static int ignored(const ignore_t *ig, const char *rel, const char *name,
 typedef struct walker walker_t;
 /* Return non-zero to stop the walk. */
 typedef int (*walk_fn)(walker_t *w, const char *rel, const char *full,
-                       const struct stat *st, int depth);
+                       const os_stat_t *st, int depth);
 
 struct walker {
   const char *root; /* workspace realpath */
@@ -781,15 +785,13 @@ static void walk_dir(walker_t *w, const char *rel, int depth) {
     snprintf(dirfull, sizeof(dirfull), "%s/%s", w->root, rel);
   else
     snprintf(dirfull, sizeof(dirfull), "%s", w->root);
-  DIR *d = opendir(dirfull);
+  os_dir_t *d = os_dir_open(dirfull);
   if (!d)
     return;
   char **names = NULL;
   int n = 0, cap = 0;
-  struct dirent *de;
-  while ((de = readdir(d)) != NULL) {
-    if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0)
-      continue;
+  const os_dirent_t *de;
+  while ((de = os_dir_next(d)) != NULL) {
     if (n == cap) {
       cap = cap ? cap * 2 : 32;
       char **nv = realloc(names, (size_t)cap * sizeof(char *));
@@ -797,11 +799,11 @@ static void walk_dir(walker_t *w, const char *rel, int depth) {
         break;
       names = nv;
     }
-    names[n] = strdup(de->d_name);
+    names[n] = strdup(de->name);
     if (names[n])
       n++;
   }
-  closedir(d);
+  os_dir_close(d);
   qsort(names, (size_t)n, sizeof(char *), name_cmp);
   for (int i = 0; i < n && !w->stop; i++) {
     char crel[OS_PATH_MAX], cfull[OS_PATH_MAX];
@@ -810,10 +812,10 @@ static void walk_dir(walker_t *w, const char *rel, int depth) {
     int k2 = snprintf(cfull, sizeof(cfull), "%s/%s", w->root, crel);
     if (k1 >= (int)sizeof(crel) || k2 >= (int)sizeof(cfull))
       continue; /* path too long */
-    struct stat st;
-    if (lstat(cfull, &st) != 0)
+    os_stat_t st;
+    if (os_lstat(cfull, &st) != 0)
       continue;
-    int isdir = S_ISDIR(st.st_mode);
+    int isdir = st.is_dir;
     if (ignored(&w->ig, crel, names[i], isdir))
       continue;
     if (w->fn(w, crel, cfull, &st, depth))
@@ -861,21 +863,18 @@ typedef struct {
 
 /* Entries directly inside a directory (for the depth boundary). */
 static int dir_entries(const char *full) {
-  DIR *d = opendir(full);
+  os_dir_t *d = os_dir_open(full);
   if (!d)
     return -1;
   int n = 0;
-  struct dirent *de;
-  while ((de = readdir(d)) != NULL) {
-    if (strcmp(de->d_name, ".") != 0 && strcmp(de->d_name, "..") != 0)
-      n++;
-  }
-  closedir(d);
+  while (os_dir_next(d))
+    n++;
+  os_dir_close(d);
   return n;
 }
 
 static int list_cb(walker_t *w, const char *rel, const char *full,
-                   const struct stat *st, int depth) {
+                   const os_stat_t *st, int depth) {
   list_ud_t *u = w->ud;
   if (u->count >= LIST_MAX) {
     if (++u->more >= LIST_COUNT_MAX) {
@@ -888,7 +887,7 @@ static int list_cb(walker_t *w, const char *rel, const char *full,
   name = name ? name + 1 : rel;
   for (int i = 0; i < depth; i++)
     cst_buf_puts(&u->b, "  ");
-  if (S_ISDIR(st->st_mode)) {
+  if (st->is_dir) {
     int k = -1;
     if (skip_dir_name(name))
       cst_buf_printf(&u->b, "%s/  (skipped)\n", name);
@@ -897,10 +896,10 @@ static int list_cb(walker_t *w, const char *rel, const char *full,
                      k == 1 ? "y" : "ies");
     else
       cst_buf_printf(&u->b, "%s/%s\n", name, k == 0 ? "  (empty)" : "");
-  } else if (S_ISLNK(st->st_mode))
+  } else if (st->is_link)
     cst_buf_printf(&u->b, "%s@\n", name);
   else
-    cst_buf_printf(&u->b, "%s  (%lld B)\n", name, (long long)st->st_size);
+    cst_buf_printf(&u->b, "%s  (%lld B)\n", name, st->size);
   u->count++;
   return 0;
 }
@@ -974,7 +973,7 @@ static int seg_match(const char *pat, const char *path) {
   pseg[pl] = 0;
   memcpy(sseg, path, sl);
   sseg[sl] = 0;
-  if (fnmatch(pseg, sseg, FNM_PERIOD) != 0)
+  if (cst_fnmatch(pseg, sseg, CST_FNM_PERIOD) != 0)
     return 0;
   if (!ps)
     return !ss;
@@ -994,11 +993,11 @@ typedef struct {
 } glob_ud_t;
 
 static int glob_cb(walker_t *w, const char *rel, const char *full,
-                   const struct stat *st, int depth) {
+                   const os_stat_t *st, int depth) {
   (void)full;
   (void)depth;
   glob_ud_t *u = w->ud;
-  if (!S_ISREG(st->st_mode))
+  if (!st->is_reg)
     return 0;
   const char *sub = rel;
   size_t bl = strlen(u->base);
@@ -1009,7 +1008,7 @@ static int glob_cb(walker_t *w, const char *rel, const char *full,
   }
   const char *name = strrchr(sub, '/');
   name = name ? name + 1 : sub;
-  int ok = u->basename_only ? fnmatch(u->pattern, name, FNM_PERIOD) == 0
+  int ok = u->basename_only ? cst_fnmatch(u->pattern, name, CST_FNM_PERIOD) == 0
                             : seg_match(u->pattern, sub);
   if (!ok)
     return 0;
@@ -1025,7 +1024,7 @@ static int glob_cb(walker_t *w, const char *rel, const char *full,
       return 1;
   }
   u->hits[u->n] = strdup(rel);
-  u->mtimes[u->n] = (double)st->st_mtime;
+  u->mtimes[u->n] = st->mtime;
   if (u->hits[u->n])
     u->n++;
   if (u->n >= GLOB_MAX * 20) {
@@ -1109,11 +1108,11 @@ typedef struct {
 } files_ud_t;
 
 static int files_cb(walker_t *w, const char *rel, const char *full,
-                    const struct stat *st, int depth) {
+                    const os_stat_t *st, int depth) {
   (void)full;
   (void)depth;
   files_ud_t *u = w->ud;
-  if (!S_ISREG(st->st_mode))
+  if (!st->is_reg)
     return 0;
   if (u->n >= u->max)
     return 1;
@@ -1275,16 +1274,16 @@ static void grep_file(grep_ud_t *u, const char *rel, const char *full) {
 }
 
 static int grep_cb(walker_t *w, const char *rel, const char *full,
-                   const struct stat *st, int depth) {
+                   const os_stat_t *st, int depth) {
   (void)depth;
   grep_ud_t *u = w->ud;
-  if (!S_ISREG(st->st_mode) || st->st_size > READ_FILE_MAX)
+  if (!st->is_reg || st->size > READ_FILE_MAX)
     return 0;
   if (u->glob) {
     const char *name = strrchr(rel, '/');
     name = name ? name + 1 : rel;
-    int ok = strchr(u->glob, '/') ? fnmatch(u->glob, rel, 0) == 0
-                                  : fnmatch(u->glob, name, 0) == 0;
+    int ok = strchr(u->glob, '/') ? cst_fnmatch(u->glob, rel, 0) == 0
+                                  : cst_fnmatch(u->glob, name, 0) == 0;
     if (!ok)
       return 0;
   }
@@ -1391,32 +1390,4 @@ int cst_tool_grep(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
   return tool_take_buf(r, &out, 0);
 }
 
-#else /* _WIN32: directory tools are not implemented natively */
 
-int cst_tool_list_dir(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
-                      cst_tool_result_t *r) {
-  (void)ctx;
-  (void)c;
-  return tool_set_result(r, "error: list_dir is not available on Windows; "
-                            "use run_shell", 1);
-}
-int cst_workspace_files(const char *ws, char ***out, int max) {
-  (void)ws;
-  (void)max;
-  *out = NULL;
-  return 0;
-}
-int cst_tool_glob(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
-                  cst_tool_result_t *r) {
-  (void)ctx;
-  (void)c;
-  return tool_set_result(r, "error: glob is not available on Windows", 1);
-}
-int cst_tool_grep(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
-                  cst_tool_result_t *r) {
-  (void)ctx;
-  (void)c;
-  return tool_set_result(r, "error: grep is not available on Windows", 1);
-}
-
-#endif
diff --git a/src/tools/patch.c b/src/tools/patch.c
index b815757..1fc124b 100644
--- a/src/tools/patch.c
+++ b/src/tools/patch.c
@@ -1,4 +1,5 @@
 #include "cst_agent.h"
+#include "cst_util.h"
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -129,9 +130,9 @@ static int parse_hunk_header(const char *p, size_t n, long *a, long *b,
   return -1;
 }
 
-int cst_patch_apply_buffer(const char *orig, size_t olen, const char *hunks,
-                           size_t hlen, char **out, size_t *out_len,
-                           int *nhunks, char *err, size_t err_sz) {
+static int patch_core(const char *orig, size_t olen, const char *hunks,
+                      size_t hlen, char **out, size_t *out_len, int *nhunks,
+                      char *err, size_t err_sz) {
   lines_t file = {0}, hl = {0};
   lines_t old_seq = {0}, new_seq = {0};
   int rc = -1;
@@ -315,3 +316,47 @@ done:
   free(new_seq.v);
   return rc;
 }
+
+/* A CRLF file is patched as LF (the model's hunks usually are) and written
+ * back as CRLF; a BOM is kept out of the first line's context. */
+int cst_patch_apply_buffer(const char *orig, size_t olen, const char *hunks,
+                           size_t hlen, char **out, size_t *out_len,
+                           int *nhunks, char *err, size_t err_sz) {
+  size_t bom = orig ? cst_bom_len(orig, olen) : 0;
+  int crlf = orig && cst_text_is_crlf(orig, olen);
+  if (!bom && !crlf)
+    return patch_core(orig, olen, hunks, hlen, out, out_len, nhunks, err,
+                      err_sz);
+  if (out)
+    *out = NULL;
+  char *o = malloc(olen - bom + 1), *h = malloc(hlen + 1), *res = NULL;
+  size_t rlen = 0;
+  int rc = -1;
+  if (!o || !h) {
+    snprintf(err, err_sz, "oom");
+    goto done;
+  }
+  memcpy(o, orig + bom, olen - bom);
+  o[olen - bom] = 0;
+  size_t on = olen - bom, hn = hlen;
+  if (hlen)
+    memcpy(h, hunks, hlen);
+  h[hlen] = 0;
+  if (crlf) {
+    on = cst_crlf_to_lf(o, on);
+    hn = cst_crlf_to_lf(h, hn);
+  }
+  rc = patch_core(o, on, h, hn, &res, &rlen, nhunks, err, err_sz);
+  if (rc == 0) {
+    *out = cst_text_restyle(res, rlen, crlf, bom != 0, out_len);
+    if (!*out) {
+      snprintf(err, err_sz, "oom");
+      rc = -1;
+    }
+  }
+done:
+  free(res);
+  free(o);
+  free(h);
+  return rc;
+}
diff --git a/src/tools/registry.c b/src/tools/registry.c
index c87996b..9f056ce 100644
--- a/src/tools/registry.c
+++ b/src/tools/registry.c
@@ -6,9 +6,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#ifndef _WIN32
 #include <pthread.h>
-#endif
 
 #include "cJSON.h"
 #include "cst_tools.h"
@@ -182,14 +180,9 @@ const char *cst_tool_profile_name(int p) {
 #define DYN_MAX 256
 static cst_tool_def_t *g_dyn[DYN_MAX];
 static atomic_int g_ndyn;
-#ifndef _WIN32
 static pthread_mutex_t g_dyn_mu = PTHREAD_MUTEX_INITIALIZER;
 #define DYN_LOCK() pthread_mutex_lock(&g_dyn_mu)
 #define DYN_UNLOCK() pthread_mutex_unlock(&g_dyn_mu)
-#else
-#define DYN_LOCK() ((void)0)
-#define DYN_UNLOCK() ((void)0)
-#endif
 
 int cst_tool_count(void) { return NTOOLS + atomic_load(&g_ndyn); }
 
diff --git a/src/tools/tools.c b/src/tools/tools.c
index a3079ca..9c33f1e 100644
--- a/src/tools/tools.c
+++ b/src/tools/tools.c
@@ -238,6 +238,22 @@ static int write_content(const ctl_tool_call_t *call, const char **content,
   return *content ? 0 : -1;
 }
 
+/* Overwriting a CRLF and/or BOM file with plain LF text keeps the file's
+ * style: malloc'd restyled copy, or NULL to write content as given. */
+static char *keep_text_style(const char *oldc, size_t olen, const char *s,
+                             size_t n, size_t *out_len) {
+  if (!oldc)
+    return NULL;
+  int has_crlf = 0;
+  for (size_t i = 1; i < n && !has_crlf; i++)
+    has_crlf = s[i] == '\n' && s[i - 1] == '\r';
+  int crlf = !has_crlf && cst_text_is_crlf(oldc, olen);
+  int bom = cst_bom_len(oldc, olen) && !cst_bom_len(s, n);
+  if (!crlf && !bom)
+    return NULL;
+  return cst_text_restyle(s, n, crlf, 1, out_len);
+}
+
 int cst_preview_write_file(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
                            char **out) {
   const char *path = tool_arg(c, "path");
@@ -252,11 +268,18 @@ int cst_preview_write_file(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
   char *oldc = NULL;
   if (cst_sandbox_resolve(ctx->workspace_root, path, full, sizeof(full)) == 0)
     oldc = tool_slurp(full, &olen, 0);
+  size_t sn = 0;
+  char *styled = keep_text_style(oldc, olen, content, n, &sn);
+  if (styled) {
+    content = styled;
+    n = sn;
+  }
   cst_buf_t b = {0};
   cst_buf_printf(&b, "%s %s (%zu bytes)\n", oldc ? "overwrite" : "create",
                  path, n);
   tool_append_diff(&b, path, oldc, olen, content, n);
   free(oldc);
+  free(styled);
   *out = cst_buf_steal(&b);
   return 0;
 }
@@ -276,14 +299,22 @@ int cst_tool_write_file(const char *workspace_root, const ctl_tool_call_t *call,
 
   size_t olen = 0;
   char *oldc = tool_slurp(full, &olen, 0);
+  size_t sn = 0;
+  char *styled = keep_text_style(oldc, olen, content, n, &sn);
+  if (styled) {
+    content = styled;
+    n = sn;
+  }
   if (tool_write_whole(full, content, n) != 0) {
     free(oldc);
+    free(styled);
     return tool_set_resultf(r, 1, "error: cannot write file: %.200s", path);
   }
   cst_buf_t b = {0};
   cst_buf_printf(&b, "wrote %s (%zu bytes)\n", path, n);
   tool_append_diff(&b, path, oldc, olen, content, n);
   free(oldc);
+  free(styled);
   return tool_take_buf(r, &b, 0);
 }
 
diff --git a/src/tui.c b/src/tui.c
index c58c4a6..ae63e70 100644
--- a/src/tui.c
+++ b/src/tui.c
@@ -41,11 +41,12 @@
 
 static int g_nocolor; /* NO_COLOR */
 static int g_ascii;   /* non-UTF-8 locale or CST_ASCII=1 */
+static int g_logo_text; /* console font lacks the logo's block glyphs */
 static int g_utf8 = 1; /* locale can show non-ASCII text */
 #define HAS_COLOR() (!g_nocolor && has_colors())
 
-/* Curses: ncursesw on Unix, PDCurses (wide) on Windows. */
-#if defined(CST_USE_PDCURSES) || defined(_WIN32)
+/* Curses: ncursesw (Unix and Windows), or PDCurses (wide) on Windows. */
+#if defined(CST_USE_PDCURSES)
 #ifndef PDC_WIDE
 #define PDC_WIDE 1
 #endif
@@ -62,10 +63,23 @@ static int g_utf8 = 1; /* locale can show non-ASCII text */
 #ifndef KEY_RESIZE
 #define KEY_RESIZE 0632
 #endif
-#define wcwidth cst_wcwidth /* MinGW often lacks wcwidth */
 #else
 #include <ncurses.h>
 #endif
+#ifdef _WIN32
+#define wcwidth cst_wcwidth /* MinGW often lacks wcwidth */
+#endif
+
+/* The Windows console (conhost/ConPTY) loses wide characters on insert or
+ * delete-character, so curses must repaint cells instead. */
+static WINDOW *tui_newwin(int rows, int cols, int y, int x) {
+  WINDOW *w = newwin(rows, cols, y, x);
+#ifdef _WIN32
+  if (w)
+    idcok(w, FALSE);
+#endif
+  return w;
+}
 
 #ifdef _WIN32
 static void cst_usleep(unsigned usec) {
@@ -1876,10 +1890,10 @@ static void git_branch(const char *dir, char *out, size_t sz) {
   FILE *f = NULL;
   for (int depth = 0; depth < 64 && d[0]; depth++) {
     snprintf(p, sizeof(p), "%s/.git/HEAD", d);
-    if ((f = fopen(p, "r")) != NULL)
+    if ((f = fopen(p, "rb")) != NULL)
       break;
     snprintf(p, sizeof(p), "%s/.git", d);
-    FILE *g = fopen(p, "r");
+    FILE *g = fopen(p, "rb");
     if (g) {
       int ok = fgets(line, sizeof(line), g) && strncmp(line, "gitdir: ", 8) == 0;
       fclose(g);
@@ -1889,7 +1903,7 @@ static void git_branch(const char *dir, char *out, size_t sz) {
                     ? snprintf(p, sizeof(p), "%s/HEAD", line + 8)
                     : snprintf(p, sizeof(p), "%s/%s/HEAD", d, line + 8);
         if (n > 0 && (size_t)n < sizeof(p))
-          f = fopen(p, "r");
+          f = fopen(p, "rb");
         break;
       }
     }
@@ -2322,7 +2336,7 @@ static void draw_home(tui_t *t) {
   getmaxyx(t->logw, h, w);
   int box_top = t->in_y - t->log_y;
   int box_bot = box_top + t->in_h;
-  if (g_ascii || !g_utf8) {
+  if (g_ascii || !g_utf8 || g_logo_text) {
     int x = (w - 8) / 2, y = box_top - 2;
     if (y >= 0) {
       draw_ansi_at(t->logw, y, x, 3, "cst", CP_LOGO_DIM, 1, 0);
@@ -2805,12 +2819,107 @@ static int input_visual_rows(const tui_t *t) {
   return rows;
 }
 
+#ifdef _WIN32
+static DWORD g_con_in_mode;
+static int g_con_in_saved;
+
+/* QuickEdit makes the console select text itself and swallow the clicks;
+ * it is off while the TUI owns the mouse and restored on exit. */
+static void win_console_mouse(int on) {
+  HANDLE h = GetStdHandle(STD_INPUT_HANDLE);
+  DWORD m;
+  if (!GetConsoleMode(h, &m))
+    return;
+  if (!g_con_in_saved) {
+    g_con_in_mode = m;
+    g_con_in_saved = 1;
+  }
+  if (on)
+    m = (m & ~(DWORD)ENABLE_QUICK_EDIT_MODE) | ENABLE_MOUSE_INPUT |
+        ENABLE_EXTENDED_FLAGS;
+  else
+    m = g_con_in_mode | ENABLE_EXTENDED_FLAGS;
+  SetConsoleMode(h, m);
+}
+
+static CONSOLE_FONT_INFOEX g_con_font;
+static int g_con_font_saved;
+
+/* conhost has no glyph fallback: NSimSun, the default on Chinese systems,
+ * draws U+2580 as an empty box. */
+static int win_font_has(const WCHAR *face, WCHAR ch) {
+  HDC dc = CreateCompatibleDC(NULL);
+  if (!dc)
+    return 1;
+  HFONT font = CreateFontW(16, 0, 0, 0, FW_NORMAL, 0, 0, 0, DEFAULT_CHARSET,
+                           0, 0, 0, FF_MODERN, face);
+  WORD idx = 0;
+  int ok = 1;
+  if (font) {
+    HGDIOBJ old = SelectObject(dc, font);
+    if (GetGlyphIndicesW(dc, &ch, 1, &idx, GGI_MARK_NONEXISTING_GLYPHS) == 1)
+      ok = idx != 0xffff;
+    SelectObject(dc, old);
+    DeleteObject(font);
+  }
+  DeleteDC(dc);
+  return ok;
+}
+
+/* Raster fonts cannot draw UTF-8 box drawing or CJK; switch the console to
+ * a TrueType font of the same height while the TUI runs. */
+static void win_console_font(int on) {
+  HANDLE h = GetStdHandle(STD_OUTPUT_HANDLE);
+  if (!on) {
+    if (g_con_font_saved)
+      SetCurrentConsoleFontEx(h, FALSE, &g_con_font);
+    g_con_font_saved = 0;
+    return;
+  }
+  CONSOLE_FONT_INFOEX f = {.cbSize = sizeof f};
+  if (!GetCurrentConsoleFontEx(h, FALSE, &f))
+    return;
+  if (!(f.FontFamily & TMPF_TRUETYPE)) {
+    g_con_font = f;
+    CONSOLE_FONT_INFOEX tt = {.cbSize = sizeof tt};
+    tt.dwFontSize.Y = f.dwFontSize.Y > 0 ? f.dwFontSize.Y : 16;
+    tt.FontFamily = FF_MODERN | TMPF_TRUETYPE;
+    tt.FontWeight = FW_NORMAL;
+    wcscpy(tt.FaceName, GetACP() == 936 ? L"NSimSun" : L"Consolas");
+    if (!SetCurrentConsoleFontEx(h, FALSE, &tt))
+      return;
+    g_con_font_saved = 1;
+    f = tt;
+  }
+  if (!getenv("WT_SESSION") && !win_font_has(f.FaceName, 0x2580))
+    g_logo_text = 1;
+}
+#endif
+
+#define MOUSE_RUN_MAX 16
+/* getmouse() hands out a run of queued events newest first (the Windows
+ * console driver queues press, motion and release together); returns them
+ * oldest first. */
+static int get_mouse_run(MEVENT *out, int max) {
+  int n = 0;
+  while (n < max && getmouse(&out[n]) == OK)
+    n++;
+  for (int i = 0; i < n / 2; i++) {
+    MEVENT tmp = out[i];
+    out[i] = out[n - 1 - i];
+    out[n - 1 - i] = tmp;
+  }
+  return n;
+}
+
 static void apply_mouse(const tui_t *t) {
   mousemask(t->mouse_on ? (mmask_t)(ALL_MOUSE_EVENTS | REPORT_MOUSE_POSITION)
                         : 0,
             NULL);
   mouseinterval(0);
-#ifdef NCURSES_VERSION
+#ifdef _WIN32
+  win_console_mouse(t->mouse_on);
+#elif defined(NCURSES_VERSION)
   /* ncurses only asks for presses and releases (1000). 1002 also reports
    * motion while a button is held, for drag selection; terminals treat it as
    * replacing 1000, so it goes after mousemask and is turned off explicitly. */
@@ -2869,8 +2978,8 @@ static void layout(tui_t *t) {
     int top = (t->rows - 1 - block) / 2;
     t->in_y = clampi(top + LOGO_H + 1, 0, t->rows - 1 - t->in_h);
     t->log_x = t->log_y = 0;
-    t->logw = newwin(t->rows - 1, t->cols, 0, 0);
-    t->status = newwin(1, t->cols - 2, t->rows - 1, 1);
+    t->logw = tui_newwin(t->rows - 1, t->cols, 0, 0);
+    t->status = tui_newwin(1, t->cols - 2, t->rows - 1, 1);
   } else {
     int mw = t->cols - t->side_w;
     t->in_y = t->rows - 1 - t->in_h;
@@ -2885,14 +2994,14 @@ static void layout(tui_t *t) {
       t->todo_rows = 0;
       log_h = t->in_y - t->log_y > 0 ? t->in_y - t->log_y : 1;
     }
-    t->logw = newwin(log_h, mw - 2, t->log_y, 1);
+    t->logw = tui_newwin(log_h, mw - 2, t->log_y, 1);
     if (t->todo_rows)
-      t->todow = newwin(t->todo_rows, mw - 2, t->log_y + log_h, 1);
-    t->status = newwin(1, mw - 2, t->rows - 1, 1);
+      t->todow = tui_newwin(t->todo_rows, mw - 2, t->log_y + log_h, 1);
+    t->status = tui_newwin(1, mw - 2, t->rows - 1, 1);
     if (t->side_w)
-      t->side = newwin(t->rows, t->side_w, 0, mw);
+      t->side = tui_newwin(t->rows, t->side_w, 0, mw);
   }
-  t->input = newwin(t->in_h, t->in_w, t->in_y, t->in_x);
+  t->input = tui_newwin(t->in_h, t->in_w, t->in_y, t->in_x);
   if (HAS_COLOR()) {
     wbkgdset(t->logw, COLOR_PAIR(CP_PANEL));
     wbkgdset(t->status, COLOR_PAIR(CP_PANEL));
@@ -3495,7 +3604,7 @@ static int picker_run(tui_t *t, const char *title, char items[][128], int n,
       redraw_all(t); /* uncover what a larger dialog hid */
     last_dh = dh;
     last_dw = dw;
-    dlg = newwin(dh, dw, dy, dx);
+    dlg = tui_newwin(dh, dw, dy, dx);
     if (!dlg)
       break;
     keypad(dlg, TRUE);
@@ -3549,9 +3658,14 @@ static int picker_run(tui_t *t, const char *title, char items[][128], int n,
         layout(t);
         redraw_all(t);
       } else if (wch == KEY_MOUSE) {
-        MEVENT ev;
-        if (getmouse(&ev) != OK)
+        MEVENT evs[MOUSE_RUN_MAX], ev;
+        int ne = get_mouse_run(evs, MOUSE_RUN_MAX), k0 = ne - 1;
+        if (ne == 0)
           continue;
+        for (int i = 0; i < ne; i++)
+          if (evs[i].bstate & (BUTTON1_PRESSED | BUTTON1_CLICKED))
+            k0 = i; /* a click anywhere in the run wins over its release */
+        ev = evs[k0];
         if (ev.bstate & BUTTON4_PRESSED) {
           if (sel > 0)
             sel--;
@@ -4301,6 +4415,34 @@ static void cmd_tools(tui_t *t, char *arg, int *quit) {
   }
 }
 
+static void cmd_sandbox(tui_t *t, char *arg, int *quit) {
+  (void)quit;
+  if (arg && strcmp(arg, "reset-labels") == 0) {
+    char *rep = NULL;
+    int n = cst_sandbox_reset_labels(&rep);
+    if (rep && rep[0])
+      push_lines(t, "  ", rep);
+    push_system_line(t, n < 0   ? "(some labels could not be restored; "
+                                  "they stay listed)"
+                        : n == 0 ? "(no labeled directories)"
+                                 : "(labels restored)");
+    free(rep);
+    return;
+  }
+  int sk = cst_sandbox_probe();
+  push_system_line(t, "Shell sandbox: %s",
+                   sk == CST_SANDBOX_NONE ? "none (rule-based approval)"
+                                          : cst_sandbox_name(sk));
+  char *l = cst_sandbox_labels();
+  if (l) {
+    push_system_line(t, "Labeled Low integrity (writable by sandboxed "
+                        "commands):");
+    push_lines(t, "  ", l);
+    push_system_line(t, "/sandbox reset-labels restores their old labels");
+    free(l);
+  }
+}
+
 static void cmd_permissions(tui_t *t, char *arg, int *quit) {
   (void)quit;
   cst_perms_t *p = cst_agent_perms(t->agent);
@@ -4537,7 +4679,7 @@ static void cmd_export(tui_t *t, char *arg, int *quit) {
     *sl = 0;
     os_mkdir_p(dir, 0755);
   }
-  FILE *fp = fopen(path, "w");
+  FILE *fp = fopen(path, "wb");
   if (!fp) {
     push_system_line(t, "Error: cannot write %s", path);
     return;
@@ -4569,9 +4711,19 @@ static void cmd_export(tui_t *t, char *arg, int *quit) {
   push_system_line(t, "(exported to %s)", path);
 }
 
+#ifdef _WIN32
+#define COPY_VIA "clipboard"
+#else
+#define COPY_VIA "OSC 52"
+#endif
+
 /* Puts text on the terminal's clipboard; returns the bytes sent, 0 on
  * failure. */
 static size_t osc52_copy(const char *text, size_t n) {
+#ifdef _WIN32
+  if (os_clipboard_set(text, n) == 0)
+    return n; /* conhost has no OSC 52 */
+#endif
   static const char b64[] =
       "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
   if (n > 75000)
@@ -4614,8 +4766,8 @@ static void cmd_copy(tui_t *t, char *arg, int *quit) {
   }
   size_t n = osc52_copy(text, strlen(text));
   if (n)
-    push_system_line(t, "(copied %zu bytes of the last reply via OSC 52 — the "
-                        "terminal must allow clipboard access)", n);
+    push_system_line(t, "(copied %zu bytes of the last reply via " COPY_VIA
+                        " — the terminal must allow clipboard access)", n);
 }
 
 static void cmd_init(tui_t *t, char *arg, int *quit) {
@@ -4945,6 +5097,8 @@ static const slash_cmd_t SLASH[] = {
      cmd_tools},
     {"permissions", "perms", "[reset]", "show saved always-allow rules", 1,
      cmd_permissions},
+    {"sandbox", "", "[reset-labels]", "shell sandbox and labeled folders", 1,
+     cmd_sandbox},
     {"approval", "", "[ask|auto|yolo]", "how tools get approved (Shift+Tab)",
      1, cmd_approval},
     {"yolo", "", "", "toggle approving everything", 1, cmd_yolo},
@@ -5530,7 +5684,7 @@ static void sel_copy(tui_t *t) {
     for (size_t i = 0; i < b.n; i++)
       chars += ((unsigned char)b.s[i] & 0xC0) != 0x80;
     char msg[96];
-    snprintf(msg, sizeof(msg), "Copied %zu characters (OSC 52)", chars);
+    snprintf(msg, sizeof(msg), "Copied %zu characters (" COPY_VIA ")", chars);
     set_status(t, msg);
     draw_status(t);
   }
@@ -6187,6 +6341,21 @@ static void insert_newline(tui_t *t) {
 }
 
 /* Paste mode: keep newlines/tabs literally; redraw once at the end. */
+#ifdef _WIN32
+static int win_key_pending(void) {
+  INPUT_RECORD rec[32];
+  DWORD n = 0;
+  HANDLE h = GetStdHandle(STD_INPUT_HANDLE);
+  if (!PeekConsoleInputW(h, rec, 32, &n))
+    return 0;
+  for (DWORD i = 0; i < n; i++)
+    if (rec[i].EventType == KEY_EVENT && rec[i].Event.KeyEvent.bKeyDown &&
+        rec[i].Event.KeyEvent.uChar.UnicodeChar)
+      return 1;
+  return 0;
+}
+#endif
+
 static void paste_char(tui_t *t, wint_t wch) {
   if (wch == 13) {
     input_put_byte(t, '\n');
@@ -6207,20 +6376,31 @@ static void paste_char(tui_t *t, wint_t wch) {
 }
 
 int cst_tui_run(cst_agent_t *agent) {
+#ifdef _WIN32
+  setlocale(LC_ALL, ".UTF-8");
+#else
   if (!setlocale(LC_ALL, ""))
     setlocale(LC_ALL, "C.UTF-8");
+#endif
 #ifndef _WIN32
   if (!getenv("ESCDELAY"))
     setenv("ESCDELAY", "25", 0);
 #endif
 
+#ifdef _WIN32
+  win_console_font(1);
+#endif
   initscr();
+#ifdef _WIN32
+  idcok(stdscr, FALSE);
+#endif
   raw(); /* Ctrl+C/Ctrl+Z reach us as keys instead of signals */
   noecho();
   keypad(stdscr, TRUE);
   curs_set(1);
   theme_init();
-#ifdef NCURSES_VERSION
+#if defined(NCURSES_VERSION) && !defined(_WIN32)
+  /* the Windows console driver reads key events, not VT sequences */
   define_key("\033[200~", KEY_PASTE_BEGIN);
   define_key("\033[201~", KEY_PASTE_END);
   printf("\033[?2004h");
@@ -6375,6 +6555,18 @@ int cst_tui_run(cst_agent_t *agent) {
     if (t.sel_state == SEL_SHOWN &&
         !(rc == KEY_CODE_YES && (wch == KEY_MOUSE || wch == KEY_RESIZE)))
       sel_clear(&t);
+#ifdef _WIN32
+    /* The console has no bracketed paste: an Enter with more keys already
+     * queued is a pasted line break, not a send. */
+    if (rc == OK && !t.in_paste && (wch == 10 || wch == 13) &&
+        win_key_pending()) {
+      paste_char(&t, wch);
+      input_changed(&t);
+      after_edit(&t);
+      draw_input(&t);
+      continue;
+    }
+#endif
 
     if (!t.in_paste &&
         !(rc == KEY_CODE_YES &&
@@ -6453,12 +6645,13 @@ int cst_tui_run(cst_agent_t *agent) {
         continue;
       }
       if (wch == KEY_MOUSE) {
-        MEVENT ev;
-        if (getmouse(&ev) == OK) {
-          if (on_mouse(&t, &ev, busy) == -2)
+        MEVENT evs[MOUSE_RUN_MAX];
+        int ne = get_mouse_run(evs, MOUSE_RUN_MAX);
+        for (int i = 0; i < ne; i++)
+          if (on_mouse(&t, &evs[i], busy) == -2)
             goto out;
+        if (ne)
           draw_input(&t); /* keep the terminal cursor in the box */
-        }
         continue;
       }
       int wdir;
@@ -6667,7 +6860,11 @@ out:
     usleep(100000); /* let a /models probe finish before curl cleanup */
 
   tui_free(&t);
-#ifdef NCURSES_VERSION
+#ifdef _WIN32
+  if (g_con_in_saved)
+    win_console_mouse(0);
+  win_console_font(0);
+#elif defined(NCURSES_VERSION)
   kitty_restore();
   printf("\033[?1002l\033[?2004l");
   fflush(stdout);
diff --git a/src/undo.c b/src/undo.c
index a8ce87d..62ae104 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -9,10 +9,7 @@
 #include <string.h>
 #include <sys/stat.h>
 
-#ifndef _WIN32
-#include <dirent.h>
 #include <unistd.h>
-#endif
 
 #include "cst_agent.h"
 #include "cst_undo.h"
@@ -75,7 +72,7 @@ static int put(const char *p, const char *d, size_t n) {
 }
 
 static int manifest_has(const char *mf, const char *rel) {
-  FILE *fp = fopen(mf, "r");
+  FILE *fp = fopen(mf, "rb");
   if (!fp)
     return 0;
   char line[1400];
@@ -120,7 +117,7 @@ int cst_undo_snapshot(const char *ws, const char *sid, const char *tag,
     return 0;
   int idx = 0;
   {
-    FILE *fp = fopen(mf, "r");
+    FILE *fp = fopen(mf, "rb");
     if (fp) {
       int ch;
       while ((ch = fgetc(fp)) != EOF)
@@ -144,7 +141,7 @@ int cst_undo_snapshot(const char *ws, const char *sid, const char *tag,
       free(data);
     }
   }
-  FILE *fp = fopen(mf, "a");
+  FILE *fp = fopen(mf, "ab");
   if (!fp)
     return -1;
   fprintf(fp, "%d\t%s\t%s\n", idx, state, rel);
@@ -152,35 +149,34 @@ int cst_undo_snapshot(const char *ws, const char *sid, const char *tag,
   return 0;
 }
 
-#ifndef _WIN32
 static int latest_tag(const char *root, char *tag, size_t n) {
-  DIR *d = opendir(root);
+  os_dir_t *d = os_dir_open(root);
   if (!d)
     return -1;
-  struct dirent *de;
+  const os_dirent_t *de;
   tag[0] = 0;
-  while ((de = readdir(d)) != NULL) {
-    if (de->d_name[0] == '.')
+  while ((de = os_dir_next(d)) != NULL) {
+    if (de->name[0] == '.')
       continue;
-    if (strcmp(de->d_name, tag) > 0)
-      snprintf(tag, n, "%s", de->d_name);
+    if (strcmp(de->name, tag) > 0)
+      snprintf(tag, n, "%s", de->name);
   }
-  closedir(d);
+  os_dir_close(d);
   return tag[0] ? 0 : -1;
 }
 
 static void rm_dir(const char *dir) {
-  DIR *d = opendir(dir);
+  os_dir_t *d = os_dir_open(dir);
   if (d) {
-    struct dirent *de;
-    while ((de = readdir(d)) != NULL) {
-      if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0)
+    const os_dirent_t *de;
+    while ((de = os_dir_next(d)) != NULL) {
+      if (strcmp(de->name, ".") == 0 || strcmp(de->name, "..") == 0)
         continue;
       char p[OS_PATH_MAX];
-      if (snprintf(p, sizeof(p), "%s/%s", dir, de->d_name) < (int)sizeof(p))
+      if (snprintf(p, sizeof(p), "%s/%s", dir, de->name) < (int)sizeof(p))
         unlink(p);
     }
-    closedir(d);
+    os_dir_close(d);
   }
   rmdir(dir);
 }
@@ -189,14 +185,14 @@ int cst_undo_count(const char *ws, const char *sid) {
   char root[OS_PATH_MAX];
   if (undo_root(ws, sid, root, sizeof(root)) != 0)
     return 0;
-  DIR *d = opendir(root);
+  os_dir_t *d = os_dir_open(root);
   if (!d)
     return 0;
   int n = 0;
-  struct dirent *de;
-  while ((de = readdir(d)) != NULL)
-    n += de->d_name[0] != '.';
-  closedir(d);
+  const os_dirent_t *de;
+  while ((de = os_dir_next(d)) != NULL)
+    n += de->name[0] != '.';
+  os_dir_close(d);
   return n;
 }
 
@@ -214,7 +210,7 @@ int cst_undo_restore_last(const char *ws, const char *sid, char *report,
     snprintf(report, report_sz, "undo path too long");
     return -1;
   }
-  FILE *fp = fopen(mf, "r");
+  FILE *fp = fopen(mf, "rb");
   cst_buf_t rep = {0};
   int restored = 0, failed = 0;
   if (fp) {
@@ -231,10 +227,10 @@ int cst_undo_restore_last(const char *ws, const char *sid, char *report,
       *t3++ = 0;
       const char *rel = t3, *state = t2;
       char full[OS_PATH_MAX];
-      struct stat lst;
+      os_stat_t lst;
       if (!rel_ok(rel) || os_path_join(full, sizeof(full), ws, rel) != 0)
         continue;
-      if (lstat(full, &lst) == 0 && S_ISLNK(lst.st_mode)) {
+      if (os_lstat(full, &lst) == 0 && lst.is_link) {
         cst_buf_printf(&rep, "skipped %s (now a symlink)\n", rel);
         failed++;
         continue;
@@ -280,17 +276,3 @@ int cst_undo_restore_last(const char *ws, const char *sid, char *report,
   cst_buf_free(&rep);
   return failed && !restored ? -1 : 0;
 }
-#else
-int cst_undo_count(const char *ws, const char *sid) {
-  (void)ws;
-  (void)sid;
-  return 0;
-}
-int cst_undo_restore_last(const char *ws, const char *sid, char *report,
-                          size_t report_sz) {
-  (void)ws;
-  (void)sid;
-  snprintf(report, report_sz, "undo is not available on Windows");
-  return -1;
-}
-#endif
diff --git a/src/util.c b/src/util.c
index 9b72dc7..8f98d59 100644
--- a/src/util.c
+++ b/src/util.c
@@ -4,6 +4,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <wchar.h>
+#include <wctype.h>
 
 static int buf_reserve(cst_buf_t *b, size_t extra) {
   if (b->len + extra + 1 <= b->cap)
@@ -153,6 +155,213 @@ char *cst_utf8_sanitize(const char *s, size_t n, size_t *out_len) {
   return out;
 }
 
+int cst_utf8_valid(const char *s, size_t n) {
+  const unsigned char *p = (const unsigned char *)s;
+  for (size_t i = 0; i < n;) {
+    size_t k = utf8_seq_ok(p + i, n - i);
+    if (k == 0)
+      return 0;
+    i += k;
+  }
+  return 1;
+}
+
+size_t cst_bom_len(const char *s, size_t n) {
+  return n >= 3 && memcmp(s, "\xEF\xBB\xBF", 3) == 0 ? 3 : 0;
+}
+
+void cst_strip_bom(char *s, size_t *len) {
+  if (!s)
+    return;
+  size_t n = len ? *len : strlen(s);
+  if (!cst_bom_len(s, n))
+    return;
+  memmove(s, s + 3, n - 3 + 1);
+  if (len)
+    *len = n - 3;
+}
+
+size_t cst_crlf_to_lf(char *s, size_t n) {
+  size_t o = 0;
+  for (size_t i = 0; i < n; i++)
+    if (!(s[i] == '\r' && i + 1 < n && s[i + 1] == '\n'))
+      s[o++] = s[i];
+  if (o < n)
+    s[o] = 0;
+  return o;
+}
+
+int cst_text_is_crlf(const char *s, size_t n) {
+  int crlf = 0;
+  for (size_t i = 0; s && i < n; i++) {
+    if (s[i] != '\n')
+      continue;
+    if (i == 0 || s[i - 1] != '\r')
+      return 0;
+    crlf = 1;
+  }
+  return crlf;
+}
+
+char *cst_text_restyle(const char *s, size_t n, int crlf, int bom,
+                       size_t *out_len) {
+  size_t skip = cst_bom_len(s, n), extra = bom ? 3 : 0;
+  for (size_t i = skip; crlf && i < n; i++)
+    extra += s[i] == '\n' && (i == skip || s[i - 1] != '\r');
+  char *o = malloc(n - skip + extra + 1);
+  if (!o)
+    return NULL;
+  size_t k = 0;
+  if (bom) {
+    memcpy(o, "\xEF\xBB\xBF", 3);
+    k = 3;
+  }
+  for (size_t i = skip; i < n; i++) {
+    if (crlf && s[i] == '\n' && (i == skip || s[i - 1] != '\r'))
+      o[k++] = '\r';
+    o[k++] = s[i];
+  }
+  o[k] = 0;
+  if (out_len)
+    *out_len = k;
+  return o;
+}
+
+/* Next code point of a UTF-8 string; a stray byte stands for itself. */
+static int utf8_next(const char **ps) {
+  const unsigned char *p = (const unsigned char *)*ps;
+  size_t left = 0;
+  while (left < 4 && p[left])
+    left++;
+  size_t k = utf8_seq_ok(p, left);
+  if (k <= 1) {
+    *ps += 1;
+    return p[0];
+  }
+  int c = p[0] & (0x7F >> k);
+  for (size_t i = 1; i < k; i++)
+    c = (c << 6) | (p[i] & 0x3F);
+  *ps += k;
+  return c;
+}
+
+static int fold_cp(int c) {
+  if (c >= 'A' && c <= 'Z')
+    return c + 32;
+  if (c > 0x7F && c <= 0xFFFF)
+    return (int)towlower((wint_t)c);
+  return c;
+}
+
+/* p points just past '['. 1/0 = (no) match with *pp moved past ']';
+ * -1 = no closing ']' (the '[' is then a literal). */
+static int fnm_bracket(const char **pp, int c, int fold) {
+  const char *p = *pp;
+  int neg = 0, hit = 0;
+  if (*p == '!' || *p == '^') {
+    neg = 1;
+    p++;
+  }
+  int fc = fold ? fold_cp(c) : c;
+  for (int first = 1; *p && (*p != ']' || first); first = 0) {
+    if (p[0] == '[' && p[1] == ':') {
+      const char *e = strstr(p + 2, ":]");
+      if (e) {
+        char name[16];
+        size_t nl = (size_t)(e - (p + 2));
+        if (nl < sizeof(name)) {
+          memcpy(name, p + 2, nl);
+          name[nl] = 0;
+          wctype_t t = wctype(name);
+          if (t && c <= 0xFFFF && iswctype((wint_t)c, t))
+            hit = 1;
+        }
+        p = e + 2;
+        continue;
+      }
+    }
+    if (*p == '\\' && p[1])
+      p++;
+    int lo = utf8_next(&p), hi = lo;
+    if (p[0] == '-' && p[1] && p[1] != ']') {
+      p++;
+      if (*p == '\\' && p[1])
+        p++;
+      hi = utf8_next(&p);
+    }
+    if ((c >= lo && c <= hi) ||
+        (fold && fc >= fold_cp(lo) && fc <= fold_cp(hi)))
+      hit = 1;
+  }
+  if (*p != ']')
+    return -1;
+  *pp = p + 1;
+  return hit != neg;
+}
+
+int cst_fnmatch(const char *pat, const char *str, int flags) {
+#ifdef _WIN32
+  flags |= CST_FNM_CASEFOLD;
+#endif
+  int fold = (flags & CST_FNM_CASEFOLD) != 0;
+  const char *p = pat, *s = str;
+  const char *star_p = NULL, *star_s = NULL;
+  if ((flags & CST_FNM_PERIOD) && s[0] == '.' && p[0] != '.' &&
+      !(p[0] == '\\' && p[1] == '.'))
+    return 1;
+  while (*s) {
+    if (*p == '*') {
+      while (*p == '*')
+        p++;
+      if (!*p)
+        return 0;
+      star_p = p;
+      star_s = s;
+      continue;
+    }
+    const char *sn = s;
+    int c = utf8_next(&sn);
+    if (*p == '?') {
+      p++;
+      s = sn;
+      continue;
+    }
+    if (*p == '[') {
+      const char *q = p + 1;
+      int r = fnm_bracket(&q, c, fold);
+      if (r == 1) {
+        p = q;
+        s = sn;
+        continue;
+      }
+      if (r == 0)
+        goto backtrack;
+    }
+    {
+      const char *q = p;
+      if (*q == '\\' && q[1])
+        q++;
+      if (*q) {
+        int pc = utf8_next(&q);
+        if (pc == c || (fold && fold_cp(pc) == fold_cp(c))) {
+          p = q;
+          s = sn;
+          continue;
+        }
+      }
+    }
+  backtrack:
+    if (!star_p)
+      return 1;
+    utf8_next(&star_s);
+    s = star_s;
+    p = star_p;
+  }
+  while (*p == '*')
+    p++;
+  return *p ? 1 : 0;
+}
+
 uint64_t cst_fnv1a64(uint64_t h, const void *data, size_t n) {
   const unsigned char *p = data;
   for (size_t i = 0; i < n; i++) {
diff --git a/tests/cst_test_util.h b/tests/cst_test_util.h
new file mode 100644
index 0000000..0b36f2e
--- /dev/null
+++ b/tests/cst_test_util.h
@@ -0,0 +1,208 @@
+/* Portable helpers for the test programs: scratch dirs, env, recursive
+ * delete, symlinks and (with CST_TEST_SOCKETS) a loopback socket layer. */
+#ifndef CST_TEST_UTIL_H
+#define CST_TEST_UTIL_H
+
+#include "os_compat.h"
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef _WIN32
+#ifdef CST_TEST_SOCKETS
+#include <winsock2.h> /* before windows.h */
+#include <ws2tcpip.h>
+#endif
+#include <direct.h>
+#include <io.h>
+#include <windows.h>
+#else
+#include <sys/stat.h>
+#include <unistd.h>
+#endif
+
+#if defined(__GNUC__)
+#define CST_TEST_UNUSED __attribute__((unused))
+#else
+#define CST_TEST_UNUSED
+#endif
+
+/* mkdir(path, mode) that also builds on Windows. */
+#define test_mkdir(p, mode) os_mkdir((p), (mode))
+
+/* Fresh empty directory "<tmp>/<tag>-<pid>-<n>"; 0 on success. */
+static CST_TEST_UNUSED int test_tmpdir(char *out, size_t n, const char *tag) {
+  static int seq;
+  char base[1024];
+  if (os_temp_dir(base, sizeof(base)) != 0)
+    snprintf(base, sizeof(base), ".");
+  for (int i = 0; i < 100; i++) {
+    int k = snprintf(out, n, "%s/%s-%d-%d", base, tag, os_getpid(), seq++);
+    if (k < 0 || (size_t)k >= n)
+      return -1;
+#ifdef _WIN32
+    int rc = _mkdir(out);
+#else
+    int rc = mkdir(out, 0755);
+#endif
+    if (rc == 0)
+      return 0;
+    if (errno != EEXIST)
+      return -1;
+  }
+  return -1;
+}
+
+/* rm -rf without a shell; links are removed, never followed. */
+static CST_TEST_UNUSED int test_rmrf(const char *path) {
+  os_stat_t st;
+  if (os_lstat(path, &st) != 0)
+    return 0;
+  if (st.is_link) {
+#ifdef _WIN32
+    if (RemoveDirectoryA(path) || DeleteFileA(path))
+      return 0;
+    return -1;
+#else
+    return unlink(path);
+#endif
+  }
+  if (!st.is_dir) {
+#ifdef _WIN32
+    SetFileAttributesA(path, FILE_ATTRIBUTE_NORMAL);
+#endif
+    return remove(path);
+  }
+  os_dir_t *d = os_dir_open(path);
+  if (d) {
+    const os_dirent_t *e;
+    while ((e = os_dir_next(d))) {
+      if (!strcmp(e->name, ".") || !strcmp(e->name, ".."))
+        continue;
+      size_t L = strlen(path) + strlen(e->name) + 2;
+      char *c = malloc(L);
+      if (!c)
+        break;
+      snprintf(c, L, "%s/%s", path, e->name);
+      test_rmrf(c);
+      free(c);
+    }
+    os_dir_close(d);
+  }
+#ifdef _WIN32
+  return _rmdir(path);
+#else
+  return rmdir(path);
+#endif
+}
+
+/* 0 on success; -1 when the platform or account cannot make links (Windows
+ * without Developer Mode or admin rights): callers skip those checks. */
+static CST_TEST_UNUSED int test_symlink(const char *target, const char *link) {
+#ifdef _WIN32
+  wchar_t *wt = os_utf8_to_wide(target), *wl = os_utf8_to_wide(link);
+  int ok = 0;
+  if (wt && wl) {
+    for (wchar_t *p = wt; *p; p++)
+      if (*p == L'/')
+        *p = L'\\';
+    DWORD attr = GetFileAttributesW(wt);
+    if (attr == INVALID_FILE_ATTRIBUTES) {
+      /* relative targets resolve against the link's directory */
+      wchar_t *slash = wcsrchr(wl, L'/');
+      if (!slash)
+        slash = wcsrchr(wl, L'\\');
+      if (slash && wt[0] != L'\\' && !(wt[0] && wt[1] == L':')) {
+        size_t dl = (size_t)(slash - wl) + 1, tl = wcslen(wt);
+        wchar_t *full = malloc((dl + tl + 1) * sizeof(wchar_t));
+        if (full) {
+          memcpy(full, wl, dl * sizeof(wchar_t));
+          memcpy(full + dl, wt, (tl + 1) * sizeof(wchar_t));
+          attr = GetFileAttributesW(full);
+          free(full);
+        }
+      }
+    }
+    DWORD flags = 0x2; /* SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE */
+    if (attr != INVALID_FILE_ATTRIBUTES && (attr & FILE_ATTRIBUTE_DIRECTORY))
+      flags |= SYMBOLIC_LINK_FLAG_DIRECTORY;
+    ok = CreateSymbolicLinkW(wl, wt, flags) != 0;
+  }
+  free(wt);
+  free(wl);
+  return ok ? 0 : -1;
+#else
+  return symlink(target, link);
+#endif
+}
+
+/* rand_r replacement (same sequence everywhere). */
+static CST_TEST_UNUSED int test_rand(unsigned *seed) {
+  *seed = *seed * 1103515245u + 12345u;
+  return (int)((*seed >> 16) & 0x7fff);
+}
+
+/* getline replacement: -1 at EOF. */
+static CST_TEST_UNUSED long test_getline(char **line, size_t *cap, FILE *fp) {
+  if (!*line || *cap == 0) {
+    *cap = 256;
+    *line = malloc(*cap);
+    if (!*line)
+      return -1;
+  }
+  size_t n = 0;
+  int c;
+  while ((c = fgetc(fp)) != EOF) {
+    if (n + 2 > *cap) {
+      size_t nc = *cap * 2;
+      char *nl = realloc(*line, nc);
+      if (!nl)
+        return -1;
+      *line = nl;
+      *cap = nc;
+    }
+    (*line)[n++] = (char)c;
+    if (c == '\n')
+      break;
+  }
+  if (n == 0)
+    return -1;
+  (*line)[n] = 0;
+  return (long)n;
+}
+
+static CST_TEST_UNUSED void test_sleep_ms(int ms) {
+#ifdef _WIN32
+  Sleep((DWORD)ms);
+#else
+  usleep((useconds_t)ms * 1000);
+#endif
+}
+
+#ifdef CST_TEST_SOCKETS
+#ifdef _WIN32
+typedef SOCKET test_sock_t;
+#define TEST_BAD_SOCK INVALID_SOCKET
+#define test_sock_close closesocket
+#ifndef MSG_NOSIGNAL
+#define MSG_NOSIGNAL 0
+#endif
+static CST_TEST_UNUSED void test_sock_init(void) {
+  WSADATA w;
+  WSAStartup(MAKEWORD(2, 2), &w);
+}
+#else
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <signal.h>
+#include <sys/socket.h>
+typedef int test_sock_t;
+#define TEST_BAD_SOCK (-1)
+#define test_sock_close close
+static CST_TEST_UNUSED void test_sock_init(void) { signal(SIGPIPE, SIG_IGN); }
+#endif
+#endif /* CST_TEST_SOCKETS */
+
+#endif
diff --git a/tests/test_apply_patch.c b/tests/test_apply_patch.c
index 1d39f78..367c5ed 100644
--- a/tests/test_apply_patch.c
+++ b/tests/test_apply_patch.c
@@ -7,6 +7,7 @@
 #include <string.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include "cst_test_util.h"
 
 static int nfail;
 
@@ -180,12 +181,12 @@ static void test_tool_multi_file(void) {
 int main(void) {
   test_buffer_basic();
   test_buffer_edge();
-  snprintf(g_ws, sizeof(g_ws), "/tmp/cst-patch-test-%d", (int)getpid());
-  mkdir(g_ws, 0755);
+  if (test_tmpdir(g_ws, sizeof(g_ws), "cst-patch-test") != 0) {
+    perror("tmpdir");
+    return 1;
+  }
   test_tool_multi_file();
-  char cmd[300];
-  snprintf(cmd, sizeof(cmd), "rm -rf %s /tmp/escape.c", g_ws);
-  if (system(cmd) != 0)
+  if (test_rmrf(g_ws) != 0)
     fprintf(stderr, "warning: cleanup failed\n");
   if (nfail) {
     fprintf(stderr, "test_apply_patch: %d failed\n", nfail);
diff --git a/tests/test_config.c b/tests/test_config.c
index 0b4678d..bcc98d6 100644
--- a/tests/test_config.c
+++ b/tests/test_config.c
@@ -9,6 +9,11 @@
 #include <string.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include "cst_test_util.h"
+#ifdef _WIN32
+#include <aclapi.h>
+#include <sddl.h>
+#endif
 
 #define CHECK(c)                                                               \
   do {                                                                         \
@@ -23,7 +28,7 @@ static char g_dir[256];
 static void write_file(const char *name, const char *text) {
   char path[512];
   snprintf(path, sizeof(path), "%s/cst-agent/%s", g_dir, name);
-  FILE *fp = fopen(path, "w");
+  FILE *fp = fopen(path, "wb");
   CHECK(fp);
   fputs(text, fp);
   fclose(fp);
@@ -57,9 +62,26 @@ static void test_creds(void) {
 
   char path[512];
   snprintf(path, sizeof(path), "%s/cst-agent/credentials", g_dir);
+#ifdef _WIN32
+  {
+    wchar_t *wp = os_utf8_to_wide(path);
+    PSECURITY_DESCRIPTOR sd = NULL;
+    LPWSTR s = NULL;
+    CHECK(wp && GetNamedSecurityInfoW(wp, SE_FILE_OBJECT,
+                                      LABEL_SECURITY_INFORMATION, NULL, NULL,
+                                      NULL, NULL, &sd) == ERROR_SUCCESS);
+    CHECK(ConvertSecurityDescriptorToStringSecurityDescriptorW(
+        sd, SDDL_REVISION_1, LABEL_SECURITY_INFORMATION, &s, NULL));
+    CHECK(wcsstr(s, L"NR") && wcsstr(s, L";ME)")); /* Low-IL cannot read */
+    LocalFree(s);
+    LocalFree(sd);
+    free(wp);
+  }
+#else
   struct stat st;
   CHECK(stat(path, &st) == 0);
   CHECK((st.st_mode & 0077) == 0);
+#endif
 
   CHECK(cst_creds_resolve("deepseek", key, sizeof(key), &from) == 0);
   CHECK(strcmp(from, "saved") == 0);
@@ -124,23 +146,20 @@ static void test_effort(void) {
 }
 
 int main(void) {
-  snprintf(g_dir, sizeof(g_dir), "/tmp/cst-config-XXXXXX");
-  CHECK(mkdtemp(g_dir));
+  CHECK(test_tmpdir(g_dir, sizeof(g_dir), "cst-config") == 0);
   setenv("XDG_CONFIG_HOME", g_dir, 1);
   unsetenv("DEEPSEEK_API_KEY");
   unsetenv("MINIMAX_API_KEY");
   unsetenv("OPENAI_API_KEY");
   char sub[300];
   snprintf(sub, sizeof(sub), "%s/cst-agent", g_dir);
-  CHECK(mkdir(sub, 0700) == 0);
+  CHECK(test_mkdir(sub, 0755) == 0);
 
   test_creds();
   test_settings();
   test_effort();
 
-  char cmd[400];
-  snprintf(cmd, sizeof(cmd), "rm -rf '%s'", g_dir);
-  CHECK(system(cmd) == 0);
+  CHECK(test_rmrf(g_dir) == 0);
   printf("test_config: OK\n");
   return 0;
 }
diff --git a/tests/test_diff.c b/tests/test_diff.c
index 17bc085..178f038 100644
--- a/tests/test_diff.c
+++ b/tests/test_diff.c
@@ -9,6 +9,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include "cst_test_util.h"
 
 static int nfail;
 
@@ -30,6 +31,11 @@ static void put(const char *p, const char *s) {
 
 /* GNU diff output, or NULL when diff is not installed. */
 static char *gnu_diff(const char *a, const char *b) {
+#ifdef _WIN32
+  (void)a;
+  (void)b;
+  return NULL; /* no GNU diff to compare against */
+#else
   char pa[] = "/tmp/cstdiffaXXXXXX", pb[] = "/tmp/cstdiffbXXXXXX";
   int fa = mkstemp(pa), fb = mkstemp(pb);
   if (fa < 0 || fb < 0)
@@ -67,6 +73,7 @@ static char *gnu_diff(const char *a, const char *b) {
   unlink(pa);
   unlink(pb);
   return out;
+#endif
 }
 
 static int have_gnu_diff(void) {
@@ -130,11 +137,11 @@ static char *random_text(unsigned *seed, int lines) {
   size_t cap = (size_t)lines * 16 + 2, n = 0;
   char *s = malloc(cap);
   for (int i = 0; i < lines; i++) {
-    const char *w = words[rand_r(seed) % 8];
-    n += (size_t)snprintf(s + n, cap - n, "%s%d\n", w, rand_r(seed) % 3);
+    const char *w = words[test_rand(seed) % 8];
+    n += (size_t)snprintf(s + n, cap - n, "%s%d\n", w, test_rand(seed) % 3);
   }
   s[n] = 0;
-  if (n && rand_r(seed) % 5 == 0)
+  if (n && test_rand(seed) % 5 == 0)
     s[n - 1] = 0; /* no newline at end of file */
   return s;
 }
@@ -146,15 +153,15 @@ static char *mutate(unsigned *seed, const char *a) {
   while (*p) {
     const char *e = strchr(p, '\n');
     size_t len = e ? (size_t)(e - p) + 1 : strlen(p);
-    int r = rand_r(seed) % 10;
+    int r = test_rand(seed) % 10;
     if (r == 0) {
       /* drop the line */
     } else if (r == 1) {
-      o += (size_t)snprintf(b + o, cap - o, "inserted%d\n", rand_r(seed) % 9);
+      o += (size_t)snprintf(b + o, cap - o, "inserted%d\n", test_rand(seed) % 9);
       memcpy(b + o, p, len);
       o += len;
     } else if (r == 2) {
-      o += (size_t)snprintf(b + o, cap - o, "changed%d\n", rand_r(seed) % 9);
+      o += (size_t)snprintf(b + o, cap - o, "changed%d\n", test_rand(seed) % 9);
     } else {
       memcpy(b + o, p, len);
       o += len;
@@ -198,7 +205,7 @@ int main(void) {
   unsigned seed = 12345;
   int ok = 0, total = 400;
   for (int i = 0; i < total; i++) {
-    char *a = random_text(&seed, 1 + (int)(rand_r(&seed) % 60));
+    char *a = random_text(&seed, 1 + (int)(test_rand(&seed) % 60));
     char *b = mutate(&seed, a);
     ok += round_trip(a, b);
     free(a);
diff --git a/tests/test_lowil.c b/tests/test_lowil.c
new file mode 100644
index 0000000..0b0d6ea
--- /dev/null
+++ b/tests/test_lowil.c
@@ -0,0 +1,184 @@
+/* Windows Low-IL shell sandbox: writes only in the workspace and the
+ * sandbox TEMP, the credentials file is unreadable, timeouts end the whole
+ * process tree, and /sandbox reset-labels restores the workspace label.
+ * Elsewhere it only checks that the kind is never reported. */
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include "cst_sandbox.h"
+#include "os_compat.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "cst_test_util.h"
+
+static int nfail;
+
+#define EXPECT(cond, msg)                                                      \
+  do {                                                                         \
+    if (!(cond)) {                                                             \
+      fprintf(stderr, "FAIL %s:%d: %s\n", __FILE__, __LINE__, msg);            \
+      nfail++;                                                                 \
+    }                                                                          \
+  } while (0)
+
+#ifdef _WIN32
+static int run(const char *ws, const char *cmd, os_run_result_t *r) {
+  memset(r, 0, sizeof(*r));
+  if (cst_sandbox_run_shell(ws, cmd, 0, r) != 0)
+    return -1;
+  return r->exit_code;
+}
+
+static int has(const os_run_result_t *r, const char *s) {
+  return r->out && strstr(r->out, s);
+}
+
+static void write_file(const char *path, const char *text) {
+  FILE *f = fopen(path, "wb");
+  if (f) {
+    fputs(text, f);
+    fclose(f);
+  }
+}
+
+static void confined(void) {
+  char root[1024], cfg[1100], ws[1100], out[1100], cred[1300], cmd[4096];
+  char wsr[1100];
+  if (test_tmpdir(root, sizeof(root), "cst-lowil") != 0) {
+    EXPECT(0, "tmpdir");
+    return;
+  }
+  snprintf(cfg, sizeof(cfg), "%s/cfg", root);
+  snprintf(ws, sizeof(ws), "%s/项目 ws", root);
+  snprintf(out, sizeof(out), "%s/outside", root);
+  test_mkdir(cfg, 0700);
+  test_mkdir(ws, 0755);
+  test_mkdir(out, 0755);
+  setenv("XDG_CONFIG_HOME", cfg, 1);
+  char cdir[1200];
+  EXPECT(os_config_dir(cdir, sizeof(cdir)) == 0, "config dir");
+  os_mkdir_p(cdir, 0700);
+  snprintf(cred, sizeof(cred), "%s/credentials", cdir);
+  write_file(cred, "deepseek=sk-test-secret\n");
+  EXPECT(os_chmod_private(cred) == 0, "label credentials");
+  EXPECT(os_realpath(ws, wsr, sizeof(wsr)) == 0, "realpath ws");
+  os_path_norm_slashes(wsr);
+
+  os_run_result_t r;
+  EXPECT(run(wsr, "echo hi > in.txt && cat in.txt", &r) == 0,
+         "write inside the workspace");
+  EXPECT(has(&r, "hi"), "output captured");
+  EXPECT(has(&r, "labeled"), "first run says the workspace was labeled");
+  os_run_result_free(&r);
+
+  EXPECT(run(wsr, "echo again > in.txt && cat in.txt", &r) == 0,
+         "second run");
+  EXPECT(!has(&r, "labeled"), "labeled only once");
+  EXPECT(!has(&r, "background"), "conhost is not a background process");
+  os_run_result_free(&r);
+
+  char *labels = cst_sandbox_labels();
+  EXPECT(labels && strstr(labels, wsr), "workspace recorded");
+  free(labels);
+
+  snprintf(cmd, sizeof(cmd), "echo x > '%s/o.txt'", out);
+  int rc = run(wsr, cmd, &r);
+  EXPECT(rc != 0, "write outside the workspace fails");
+  EXPECT(cst_sandbox_blocked(r.out, r.out_len, rc), "outside write blocked");
+  os_run_result_free(&r);
+  snprintf(cmd, sizeof(cmd), "%s/o.txt", out);
+  os_stat_t st;
+  EXPECT(os_lstat(cmd, &st) != 0, "nothing written outside");
+
+  snprintf(cmd, sizeof(cmd), "cat '%s'", cred);
+  rc = run(wsr, cmd, &r);
+  EXPECT(rc != 0 && !has(&r, "sk-test-secret"), "credentials unreadable");
+  EXPECT(cst_sandbox_blocked(r.out, r.out_len, rc), "credential read blocked");
+  os_run_result_free(&r);
+
+  EXPECT(run(wsr, "echo t > \"$TEMP/t.txt\" && cat \"$TEMP/t.txt\"", &r) == 0,
+         "TEMP is writable");
+  EXPECT(has(&r, "t"), "TEMP read back");
+  os_run_result_free(&r);
+
+  /* System32's whoami: busybox has an applet and MSYS2's cannot start at
+   * Low IL */
+  char sys[MAX_PATH];
+  UINT sl = GetSystemDirectoryA(sys, sizeof(sys));
+  for (UINT i = 0; i < sl; i++)
+    if (sys[i] == '\\')
+      sys[i] = '/';
+  snprintf(cmd, sizeof(cmd), "'%s/whoami.exe' /groups | grep S-1-16-4096",
+           sys);
+  rc = run(wsr, cmd, &r);
+  EXPECT(rc == 0, "child runs at Low integrity");
+  if (rc != 0)
+    fprintf(stderr, "whoami: exit %d: %.*s\n", rc, (int)r.out_len,
+            r.out ? r.out : "");
+  os_run_result_free(&r);
+
+  /* timeout ends background children too */
+  os_set_run_timeout(2);
+  double t0 = os_now_ms();
+  rc = run(wsr, "sleep 30 & sleep 30; echo late", &r);
+  double ms = os_now_ms() - t0;
+  EXPECT(rc == 124, "timeout exit code");
+  EXPECT(ms < 10000, "process tree killed promptly");
+  EXPECT(!has(&r, "late"), "command did not finish");
+  os_run_result_free(&r);
+  os_set_run_timeout(0);
+
+  const char *prof = getenv("USERPROFILE");
+  char profr[1100];
+  if (prof && os_realpath(prof, profr, sizeof(profr)) == 0) {
+    os_path_norm_slashes(profr);
+    rc = run(profr, "echo no", &r);
+    EXPECT(rc == 126 && has(&r, "will not label"), "profile is not labeled");
+    EXPECT(cst_sandbox_blocked(r.out, r.out_len, rc), "offers a rerun");
+    os_run_result_free(&r);
+  }
+  rc = run("C:/", "echo no", &r);
+  EXPECT(rc == 126 && has(&r, "will not label"), "drive root is not labeled");
+  os_run_result_free(&r);
+
+  char *rep = NULL;
+  EXPECT(cst_sandbox_reset_labels(&rep) >= 1, "reset-labels restored");
+  EXPECT(rep && strstr(rep, "restored"), "reset report");
+  free(rep);
+  labels = cst_sandbox_labels();
+  EXPECT(!labels, "record cleared");
+  free(labels);
+  char sddl[256];
+  EXPECT(os_win_get_label(wsr, sddl, sizeof(sddl)) == 0 &&
+             strcmp(sddl, "S:") == 0,
+         "workspace has no explicit label again");
+
+  unsetenv("XDG_CONFIG_HOME");
+  test_rmrf(root);
+}
+#endif
+
+int main(void) {
+  int kind = cst_sandbox_probe();
+  printf("test_lowil: sandbox %s\n", cst_sandbox_name(kind));
+  EXPECT(strcmp(cst_sandbox_name(CST_SANDBOX_LOWIL), "lowil") == 0, "name");
+#ifdef _WIN32
+  EXPECT(kind == CST_SANDBOX_LOWIL, "lowil available");
+  if (kind == CST_SANDBOX_LOWIL)
+    confined();
+#else
+  EXPECT(kind != CST_SANDBOX_LOWIL, "lowil is Windows only");
+  char *rep = NULL;
+  EXPECT(cst_sandbox_reset_labels(&rep) == 0 && !rep, "nothing to reset");
+  EXPECT(!cst_sandbox_labels(), "no labels");
+#endif
+  if (nfail) {
+    fprintf(stderr, "test_lowil: %d failure(s)\n", nfail);
+    return 1;
+  }
+  puts("test_lowil: OK");
+  return 0;
+}
diff --git a/tests/test_mcp.c b/tests/test_mcp.c
index 6ee86db..bf8c50e 100644
--- a/tests/test_mcp.c
+++ b/tests/test_mcp.c
@@ -14,7 +14,10 @@
 #include <string.h>
 #include <unistd.h>
 
+#include "cst_test_util.h"
+
 static int nfail;
+static char g_tmp[OS_PATH_MAX];
 
 #define CHECK(cond, msg)                                                       \
   do {                                                                         \
@@ -159,7 +162,7 @@ static int call(const char *tool, const char *k, const char *v,
   }
   cst_tool_ctx_t ctx;
   memset(&ctx, 0, sizeof(ctx));
-  ctx.workspace_root = "/tmp";
+  ctx.workspace_root = g_tmp;
   memset(r, 0, sizeof(*r));
   return cst_tool_run(&ctx, &c, r);
 }
@@ -181,6 +184,8 @@ int main(int argc, char **argv) {
     fprintf(stderr, "cannot resolve %s\n", argv[0]);
     return 1;
   }
+  if (os_temp_dir(g_tmp, sizeof(g_tmp)) != 0)
+    snprintf(g_tmp, sizeof(g_tmp), ".");
   setenv("CST_TEST_SECRET", "s3cret", 1);
   char cfg[OS_PATH_MAX + 128];
   snprintf(cfg, sizeof(cfg),
@@ -206,7 +211,7 @@ int main(int argc, char **argv) {
   cst_mcp_counts(&ready, &total);
   CHECK(ready == 0 && total == 3, "counts before start (disabled excluded)");
 
-  cst_mcp_start_all("/tmp");
+  cst_mcp_start_all(g_tmp);
   cst_mcp_wait_ready(10000);
 
   cst_mcp_info_t mi[CST_MCP_MAX];
@@ -281,7 +286,7 @@ int main(int argc, char **argv) {
 
   /* a live server stops cleanly too */
   CHECK(cst_mcp_add_config_json("fake2", cfg, NULL, "user") == 0, "re-add");
-  cst_mcp_start_all("/tmp");
+  cst_mcp_start_all(g_tmp);
   cst_mcp_wait_ready(10000);
   CHECK(cst_tool_find("mcp__fake2__echo"), "second server ready");
   t0 = os_now_ms();
diff --git a/tests/test_models.c b/tests/test_models.c
index 11246d6..00c368c 100644
--- a/tests/test_models.c
+++ b/tests/test_models.c
@@ -8,18 +8,10 @@
 #include <stdlib.h>
 #include <string.h>
 
-#ifdef _WIN32
-int main(void) {
-  puts("test_models: skipped on Windows");
-  return 0;
-}
-#else
+#define CST_TEST_SOCKETS
+#include "cst_test_util.h"
 
-#include <arpa/inet.h>
-#include <netinet/in.h>
 #include <pthread.h>
-#include <sys/socket.h>
-#include <unistd.h>
 
 #define CHECK(c)                                                               \
   do {                                                                         \
@@ -32,35 +24,38 @@ int main(void) {
 /* One canned HTTP response per accepted connection. */
 static const char *g_responses[8];
 static int g_nresp;
-static int g_listen = -1;
+static test_sock_t g_listen = TEST_BAD_SOCK;
 static char g_request[4096];
 
 static void *serve(void *arg) {
   (void)arg;
   for (int i = 0; i < g_nresp; i++) {
-    int c = accept(g_listen, NULL, NULL);
-    if (c < 0)
+    test_sock_t c = accept(g_listen, NULL, NULL);
+    if (c == TEST_BAD_SOCK)
       return NULL;
-    ssize_t n = recv(c, g_request, sizeof(g_request) - 1, 0);
+    long n = recv(c, g_request, sizeof(g_request) - 1, 0);
     g_request[n > 0 ? n : 0] = 0;
     const char *r = g_responses[i];
-    ssize_t off = 0, len = (ssize_t)strlen(r);
+    long off = 0, len = (long)strlen(r);
     while (off < len) {
-      ssize_t w = send(c, r + off, (size_t)(len - off), 0);
+      long w = send(c, r + off, (int)(len - off), 0);
       if (w <= 0)
         break;
       off += w;
     }
-    close(c);
+    test_sock_close(c);
   }
   return NULL;
 }
 
 static int start_server(void) {
+  test_sock_init();
   g_listen = socket(AF_INET, SOCK_STREAM, 0);
-  CHECK(g_listen >= 0);
+  CHECK(g_listen != TEST_BAD_SOCK);
+#ifndef _WIN32
   int one = 1;
   setsockopt(g_listen, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+#endif
   struct sockaddr_in a;
   memset(&a, 0, sizeof(a));
   a.sin_family = AF_INET;
@@ -118,7 +113,7 @@ int main(void) {
   CHECK(n == -1 && strstr(err, "500") != NULL);
 
   pthread_join(th, NULL);
-  close(g_listen);
+  test_sock_close(g_listen);
 
   /* nothing listening: network error, not an auth failure */
   n = cst_llm_list_models(base, "sk-test", ids, 8, err, sizeof(err));
@@ -127,4 +122,3 @@ int main(void) {
   puts("test_models: ok");
   return 0;
 }
-#endif
diff --git a/tests/test_os_dir.c b/tests/test_os_dir.c
new file mode 100644
index 0000000..1e1156d
--- /dev/null
+++ b/tests/test_os_dir.c
@@ -0,0 +1,147 @@
+/* cst_fnmatch and the os_dir / os_lstat layer that replaced the POSIX-only
+ * directory code; runs on every platform. */
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include "cst_util.h"
+#include "os_compat.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "cst_test_util.h"
+
+static int nfail;
+
+#define EXPECT(cond, msg)                                                      \
+  do {                                                                         \
+    if (!(cond)) {                                                             \
+      fprintf(stderr, "FAIL %s:%d: %s\n", __FILE__, __LINE__, msg);            \
+      nfail++;                                                                 \
+    }                                                                          \
+  } while (0)
+
+static void fnm(const char *pat, const char *s, int flags, int want) {
+  int got = cst_fnmatch(pat, s, flags) == 0;
+  if (got != want) {
+    fprintf(stderr, "FAIL fnmatch(\"%s\", \"%s\", %d) = %d\n", pat, s, flags,
+            got);
+    nfail++;
+  }
+}
+
+static void test_fnmatch(void) {
+  fnm("*.c", "main.c", 0, 1);
+  fnm("*.c", "main.h", 0, 0);
+  fnm("*.c", "src/main.c", 0, 1); /* '*' crosses '/' */
+  fnm("?.txt", "a.txt", 0, 1);
+  fnm("?.txt", "ab.txt", 0, 0);
+  fnm("?.txt", "中.txt", 0, 1); /* one code point */
+  fnm("[abc]x", "bx", 0, 1);
+  fnm("[!abc]x", "bx", 0, 0);
+  fnm("[a-c]x", "cx", 0, 1);
+  fnm("[[:digit:]]*", "7up", 0, 1);
+  fnm("[[:digit:]]*", "up", 0, 0);
+  fnm("\\*", "*", 0, 1);
+  fnm("\\*", "a", 0, 0);
+  fnm("*", ".hidden", CST_FNM_PERIOD, 0);
+  fnm(".*", ".hidden", CST_FNM_PERIOD, 1);
+  fnm("*", ".hidden", 0, 1);
+  fnm("*文件*", "我的文件.txt", 0, 1);
+  fnm("README*", "readme.md", CST_FNM_CASEFOLD, 1);
+#ifdef _WIN32
+  fnm("README*", "readme.md", 0, 1); /* Windows names are case-insensitive */
+#else
+  fnm("README*", "readme.md", 0, 0);
+#endif
+  fnm("", "", 0, 1);
+  fnm("a", "", 0, 0);
+}
+
+static void touch(const char *dir, const char *name) {
+  char p[1200];
+  snprintf(p, sizeof(p), "%s/%s", dir, name);
+  FILE *f = fopen(p, "wb");
+  if (f) {
+    fputs("x", f);
+    fclose(f);
+  }
+}
+
+static void test_dir(void) {
+  char root[1024], sub[1100], p[1200];
+  if (test_tmpdir(root, sizeof(root), "cst-osdir") != 0) {
+    EXPECT(0, "tmpdir");
+    return;
+  }
+  snprintf(sub, sizeof(sub), "%s/子目录", root);
+  EXPECT(test_mkdir(sub, 0755) == 0, "mkdir with a Chinese name");
+  touch(root, "a.txt");
+  touch(root, "文件 一.md");
+  touch(root, ".hidden");
+
+  int files = 0, dirs = 0, seen_cn = 0, seen_hidden = 0, dots = 0;
+  os_dir_t *d = os_dir_open(root);
+  EXPECT(d != NULL, "os_dir_open");
+  const os_dirent_t *e;
+  while (d && (e = os_dir_next(d)) != NULL) {
+    if (!strcmp(e->name, ".") || !strcmp(e->name, ".."))
+      dots++;
+    if (e->is_dir)
+      dirs++;
+    else
+      files++;
+    seen_cn |= strcmp(e->name, "文件 一.md") == 0 && !e->is_dir;
+    seen_hidden |= strcmp(e->name, ".hidden") == 0;
+    if (!strcmp(e->name, "子目录"))
+      EXPECT(e->is_dir && !e->is_link, "subdir flags");
+  }
+  os_dir_close(d);
+  EXPECT(dots == 0, "no . or .. entries");
+  EXPECT(files == 3 && dirs == 1, "entry counts");
+  EXPECT(seen_cn, "UTF-8 file name listed");
+  EXPECT(seen_hidden, "dot files listed");
+  d = os_dir_open(sub);
+  EXPECT(d != NULL && os_dir_next(d) == NULL, "empty Chinese subdir");
+  if (d)
+    os_dir_close(d);
+
+  os_stat_t st;
+  snprintf(p, sizeof(p), "%s/文件 一.md", root);
+  EXPECT(os_lstat(p, &st) == 0 && st.is_reg && !st.is_dir && st.size == 1,
+         "os_lstat on a UTF-8 file");
+  EXPECT(os_lstat(sub, &st) == 0 && st.is_dir, "os_lstat on a dir");
+  snprintf(p, sizeof(p), "%s/missing", root);
+  EXPECT(os_lstat(p, &st) != 0, "os_lstat on a missing path");
+  EXPECT(os_dir_open(p) == NULL, "os_dir_open on a missing path");
+
+  char real[1200], rr[1200];
+  EXPECT(os_realpath(sub, real, sizeof(real)) == 0 &&
+             os_realpath(root, rr, sizeof(rr)) == 0,
+         "os_realpath");
+  EXPECT(os_path_under(rr, real), "realpath of subdir is under root");
+  EXPECT(!os_path_under(real, rr), "root is not under subdir");
+
+  snprintf(p, sizeof(p), "%s/link", root);
+  int lk = test_symlink(sub, p);
+  if (lk == 0) {
+    EXPECT(os_lstat(p, &st) == 0 && st.is_link, "symlink is reported as link");
+  } else {
+    printf("test_os_dir: symlinks not permitted, link checks skipped\n");
+  }
+  test_rmrf(root);
+  EXPECT(os_lstat(root, &st) != 0, "test_rmrf removed everything");
+}
+
+int main(void) {
+  os_console_init();
+  test_fnmatch();
+  test_dir();
+  if (nfail) {
+    fprintf(stderr, "test_os_dir: %d failure(s)\n", nfail);
+    return 1;
+  }
+  puts("test_os_dir: OK");
+  return 0;
+}
diff --git a/tests/test_plugins.c b/tests/test_plugins.c
index 93bd168..743f6ba 100644
--- a/tests/test_plugins.c
+++ b/tests/test_plugins.c
@@ -14,6 +14,7 @@
 #include <string.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include "cst_test_util.h"
 
 static int nfail;
 
@@ -33,11 +34,11 @@ static void put(const char *rel, const char *text) {
   for (char *q = p + strlen(g_root) + 1; *q; q++) {
     if (*q == '/') {
       *q = 0;
-      mkdir(p, 0755);
+      test_mkdir(p, 0755);
       *q = '/';
     }
   }
-  FILE *fp = fopen(p, "w");
+  FILE *fp = fopen(p, "wb");
   if (fp) {
     fputs(text, fp);
     fclose(fp);
@@ -70,8 +71,10 @@ static void run(const char *ws, const char *tool, const char *k1,
 }
 
 int main(void) {
-  snprintf(g_root, sizeof(g_root), "/tmp/cst-plugins-%d", (int)getpid());
-  mkdir(g_root, 0755);
+  if (test_tmpdir(g_root, sizeof(g_root), "cst-plugins") != 0) {
+    perror("tmpdir");
+    return 1;
+  }
   char ws[300], cfgdir[300];
   snprintf(ws, sizeof(ws), "%s/ws", g_root);
   snprintf(cfgdir, sizeof(cfgdir), "%s/cfg", g_root);
@@ -206,9 +209,7 @@ int main(void) {
   CHECK(!cst_tool_find("skill") && !cst_tool_find("echo_args"),
         "extensions unload");
 
-  char cmd[400];
-  snprintf(cmd, sizeof(cmd), "rm -rf %s", g_root);
-  if (system(cmd) != 0)
+  if (test_rmrf(g_root) != 0)
     fprintf(stderr, "note: cleanup failed\n");
   if (nfail) {
     fprintf(stderr, "test_plugins: %d failure(s)\n", nfail);
diff --git a/tests/test_replay_real.c b/tests/test_replay_real.c
index 4eeb9ec..7a4a694 100644
--- a/tests/test_replay_real.c
+++ b/tests/test_replay_real.c
@@ -8,6 +8,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include "cst_test_util.h"
 
 /*
  * Truncation experiment on recorded model streams (tests/fixtures/sse).
@@ -79,7 +80,7 @@ static int load_trace(const char *path, trace_t *t) {
   char *line = NULL;
   size_t cap = 0;
   ssize_t n;
-  while ((n = getline(&line, &cap, fp)) > 0) {
+  while ((n = test_getline(&line, &cap, fp)) > 0) {
     if (strncmp(line, "data:", 5) != 0)
       continue;
     cJSON *j = cJSON_Parse(line + 5);
diff --git a/tests/test_sandbox.c b/tests/test_sandbox.c
index c61130f..3375982 100644
--- a/tests/test_sandbox.c
+++ b/tests/test_sandbox.c
@@ -73,6 +73,43 @@ static void test_blocked(void) {
   const char *d = "curl: (7) Failed to connect to example.com port 443 after 9 "
                   "ms: Could not connect to server\n";
   CHECK(cst_sandbox_blocked(d, strlen(d), 7));
+  const char *e = "Access is denied.\r\n";
+  CHECK(cst_sandbox_blocked(e, strlen(e), 1));
+  const char *f = "拒绝访问。\r\n";
+  CHECK(cst_sandbox_blocked(f, strlen(f), 1));
+  const char *g = "sh: C:/msys64/usr/bin/ls.exe: A dynamic link library (DLL) "
+                  "initialization routine failed. Error 0xc0000142\n";
+  CHECK(cst_sandbox_blocked(g, strlen(g), 1));
+}
+
+static void test_network_rules(void) {
+  static const char *const NET[] = {
+      "curl -fsSL https://example.com",
+      "cd x && wget http://a/b",
+      "/usr/bin/ssh host ls",
+      "C:\\tools\\curl.exe -O x",
+      "git push origin main",
+      "git --no-pager fetch",
+      "npm install",
+      "python -m pip install requests",
+      "go get example.com/x",
+      "cargo install ripgrep",
+      "Invoke-WebRequest -Uri x",
+  };
+  static const char *const LOCAL[] = {
+      "ls -la", "git status", "git commit -m push", "npm run build",
+      "make -j8", "pip list", "echo curly", "cat curl.txt",
+  };
+  for (size_t i = 0; i < sizeof(NET) / sizeof(NET[0]); i++) {
+    if (!cst_shell_uses_network(NET[i]))
+      fprintf(stderr, "expected network: %s\n", NET[i]);
+    CHECK(cst_shell_uses_network(NET[i]));
+  }
+  for (size_t i = 0; i < sizeof(LOCAL) / sizeof(LOCAL[0]); i++) {
+    if (cst_shell_uses_network(LOCAL[i]))
+      fprintf(stderr, "expected local: %s\n", LOCAL[i]);
+    CHECK(!cst_shell_uses_network(LOCAL[i]));
+  }
 }
 
 #if !defined(_WIN32)
@@ -314,6 +351,7 @@ static void test_confined(int kind) {
 int main(void) {
   test_rules();
   test_blocked();
+  test_network_rules();
   int kind = cst_sandbox_probe();
   printf("test_sandbox: sandbox %s\n", cst_sandbox_name(kind));
 #if !defined(_WIN32)
diff --git a/tests/test_session_roundtrip.c b/tests/test_session_roundtrip.c
index b6e627d..a92be93 100644
--- a/tests/test_session_roundtrip.c
+++ b/tests/test_session_roundtrip.c
@@ -2,6 +2,7 @@
 
 #include "cJSON.h"
 #include "cst_agent.h"
+#include "os_compat.h"
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -76,8 +77,11 @@ static void check_messages(cst_session_t *s) {
 }
 
 int main(void) {
-  char path[256];
-  snprintf(path, sizeof(path), "/tmp/cst-session-test-%d.jsonl", (int)getpid());
+  char path[1024], tmp[900];
+  if (os_temp_dir(tmp, sizeof(tmp)) != 0)
+    snprintf(tmp, sizeof(tmp), ".");
+  snprintf(path, sizeof(path), "%s/cst-session-test-%d.jsonl", tmp,
+           os_getpid());
   remove(path);
 
   cst_session_t *s = cst_session_open(path);
@@ -129,7 +133,7 @@ int main(void) {
   cst_session_close(s);
 
   /* legacy format: tool_calls_json stored as a string */
-  fp = fopen(path, "w");
+  fp = fopen(path, "wb");
   fprintf(fp, "{\"role\":\"assistant\",\"content\":\"\",\"tool_calls_json\":"
               "\"[{\\\"id\\\":\\\"c9\\\",\\\"type\\\":\\\"function\\\","
               "\\\"function\\\":{\\\"name\\\":\\\"run_shell\\\","
diff --git a/tests/test_shell.c b/tests/test_shell.c
index f42601b..6cf6188 100644
--- a/tests/test_shell.c
+++ b/tests/test_shell.c
@@ -8,6 +8,7 @@
 #include <string.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include "cst_test_util.h"
 
 /* run_shell must never hang the agent: timeout kills the whole process
  * group, stdin is empty, huge output is capped. */
@@ -41,8 +42,10 @@ static int sh(const char *cmd, cst_tool_result_t *r, double *ms) {
 }
 
 int main(void) {
-  snprintf(g_ws, sizeof(g_ws), "/tmp/cst-shell-test-%d", (int)getpid());
-  mkdir(g_ws, 0755);
+  if (test_tmpdir(g_ws, sizeof(g_ws), "cst-shell-test") != 0) {
+    perror("tmpdir");
+    return 1;
+  }
   cst_tool_result_t r;
   double ms;
 
@@ -81,9 +84,7 @@ int main(void) {
   EXPECT(ms < 20000, "large output does not hang");
   cst_tool_result_free(&r);
 
-  char cmd[300];
-  snprintf(cmd, sizeof(cmd), "rm -rf %s", g_ws);
-  if (system(cmd) != 0)
+  if (test_rmrf(g_ws) != 0)
     fprintf(stderr, "warning: cleanup failed\n");
   if (nfail) {
     fprintf(stderr, "test_shell: %d failed\n", nfail);
diff --git a/tests/test_skills.c b/tests/test_skills.c
index 1cde3fc..c9d8943 100644
--- a/tests/test_skills.c
+++ b/tests/test_skills.c
@@ -11,6 +11,7 @@
 #include <string.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include "cst_test_util.h"
 
 static int nfail;
 
@@ -30,11 +31,11 @@ static void put(const char *rel, const char *text) {
   for (char *q = p + strlen(g_root) + 1; *q; q++) {
     if (*q == '/') {
       *q = 0;
-      mkdir(p, 0755);
+      test_mkdir(p, 0755);
       *q = '/';
     }
   }
-  FILE *fp = fopen(p, "w");
+  FILE *fp = fopen(p, "wb");
   if (fp) {
     fputs(text, fp);
     fclose(fp);
@@ -69,8 +70,10 @@ static void frontmatter(void) {
 int main(void) {
   frontmatter();
 
-  snprintf(g_root, sizeof(g_root), "/tmp/cst-skills-%d", (int)getpid());
-  mkdir(g_root, 0755);
+  if (test_tmpdir(g_root, sizeof(g_root), "cst-skills") != 0) {
+    perror("tmpdir");
+    return 1;
+  }
   char ws[300], cfgdir[300];
   snprintf(ws, sizeof(ws), "%s/ws", g_root);
   snprintf(cfgdir, sizeof(cfgdir), "%s/cfg", g_root);
@@ -94,8 +97,8 @@ int main(void) {
     char link[512], target[512];
     snprintf(link, sizeof(link), "%s/ws/.agent/skills/forms/leak", g_root);
     snprintf(target, sizeof(target), "%s/ws/secret.txt", g_root);
-    if (symlink(target, link) != 0)
-      perror("symlink");
+    if (test_symlink(target, link) != 0)
+      fprintf(stderr, "note: no symlinks here, escape check is partial\n");
   }
 
   cst_skill_t v[CST_SKILLS_MAX];
@@ -180,9 +183,7 @@ int main(void) {
   CHECK(sp && !strstr(sp, "Skills ("), "minimal prompt unchanged");
   free(sp);
 
-  char cmd[400];
-  snprintf(cmd, sizeof(cmd), "rm -rf %s", g_root);
-  if (system(cmd) != 0)
+  if (test_rmrf(g_root) != 0)
     fprintf(stderr, "note: cleanup failed\n");
   if (nfail) {
     fprintf(stderr, "test_skills: %d failure(s)\n", nfail);
diff --git a/tests/test_sse_decode.c b/tests/test_sse_decode.c
index e772451..81a3b4a 100644
--- a/tests/test_sse_decode.c
+++ b/tests/test_sse_decode.c
@@ -7,6 +7,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include "cst_test_util.h"
 
 /* Drives cst_llm_chat_stream through CST_REPLAY_SSE with synthetic and
  * recorded (tests/fixtures/sse) streams, at several network chunk sizes. */
@@ -279,18 +280,14 @@ static void test_recorded(void) {
 }
 
 int main(void) {
-  snprintf(g_dir, sizeof(g_dir), "/tmp/cst-sse-test-%d", (int)getpid());
-  char cmd[300];
-  snprintf(cmd, sizeof(cmd), "mkdir -p %s", g_dir);
-  if (system(cmd) != 0)
+  if (test_tmpdir(g_dir, sizeof(g_dir), "cst-sse-test") != 0)
     return 1;
   test_text_reasoning_usage();
   test_parallel_calls();
   test_same_index_new_id();
   test_invalid_args_and_error();
   test_recorded();
-  snprintf(cmd, sizeof(cmd), "rm -rf %s", g_dir);
-  if (system(cmd) != 0)
+  if (test_rmrf(g_dir) != 0)
     fprintf(stderr, "warning: cleanup failed\n");
   if (nfail) {
     fprintf(stderr, "test_sse_decode: %d failed\n", nfail);
diff --git a/tests/test_subagent.c b/tests/test_subagent.c
index 2f9d96b..21e2bc8 100644
--- a/tests/test_subagent.c
+++ b/tests/test_subagent.c
@@ -15,19 +15,16 @@
 #include "cst_util.h"
 #include "os_compat.h"
 
-#include <arpa/inet.h>
+#define CST_TEST_SOCKETS
+#include "cst_test_util.h"
+
 #include <curl/curl.h>
-#include <netinet/in.h>
 #include <pthread.h>
-#include <signal.h>
 #include <stdatomic.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <sys/socket.h>
-#include <sys/stat.h>
-#include <unistd.h>
 
 static int nfail;
 
@@ -45,9 +42,9 @@ static atomic_int g_child_active, g_child_max, g_child_reqs;
 static atomic_int g_child_saw_task, g_child_saw_write, g_child_role_prompt;
 static atomic_int g_parent_saw_task;
 
-static void send_all(int fd, const char *s, size_t n) {
+static void send_all(test_sock_t fd, const char *s, size_t n) {
   while (n > 0) {
-    ssize_t w = send(fd, s, n, MSG_NOSIGNAL);
+    long w = send(fd, s, (int)n, MSG_NOSIGNAL);
     if (w <= 0)
       return;
     s += w;
@@ -55,7 +52,7 @@ static void send_all(int fd, const char *s, size_t n) {
   }
 }
 
-static void sse(int fd, cJSON *delta, const char *finish) {
+static void sse(test_sock_t fd, cJSON *delta, const char *finish) {
   cJSON *o = cJSON_CreateObject();
   cJSON *ch = cJSON_AddArrayToObject(o, "choices");
   cJSON *c0 = cJSON_CreateObject();
@@ -80,7 +77,7 @@ static void sse(int fd, cJSON *delta, const char *finish) {
   cJSON_Delete(o);
 }
 
-static void reply_text(int fd, const char *text) {
+static void reply_text(test_sock_t fd, const char *text) {
   cJSON *d = cJSON_CreateObject();
   cJSON_AddStringToObject(d, "role", "assistant");
   cJSON_AddStringToObject(d, "content", text);
@@ -90,7 +87,7 @@ static void reply_text(int fd, const char *text) {
 }
 
 /* calls: {name, args_json} pairs */
-static void reply_calls(int fd, const char *const *calls, int n) {
+static void reply_calls(test_sock_t fd, const char *const *calls, int n) {
   for (int i = 0; i < n; i++) {
     cJSON *d = cJSON_CreateObject();
     cJSON *tc = cJSON_AddArrayToObject(d, "tool_calls");
@@ -121,7 +118,7 @@ static int has_tool(const cJSON *body, const char *name) {
   return 0;
 }
 
-static void handle(int fd, const char *body_txt) {
+static void handle(test_sock_t fd, const char *body_txt) {
   cJSON *body = cJSON_Parse(body_txt);
   const cJSON *msgs = cJSON_GetObjectItemCaseSensitive(body, "messages");
   int nm = cJSON_GetArraySize(msgs);
@@ -155,9 +152,9 @@ static void handle(int fd, const char *body_txt) {
     if (strstr(sys->valuestring, "Role instructions:\nYou only read."))
       atomic_store(&g_child_role_prompt, 1);
     if (strstr(user, "Slow")) {
-      usleep(4000 * 1000); /* cancelled before this ends */
+      test_sleep_ms(4000); /* cancelled before this ends */
     } else {
-      usleep(300 * 1000);
+      test_sleep_ms(300);
     }
     if (strcmp(last_role, "user") == 0) {
       const char *calls[] = {"read_file", "{\"path\":\"a.txt\"}"};
@@ -206,13 +203,13 @@ static void handle(int fd, const char *body_txt) {
 }
 
 static void *conn_main(void *p) {
-  int fd = (int)(intptr_t)p;
+  test_sock_t fd = (test_sock_t)(intptr_t)p;
   cst_buf_t req = {0};
   char tmp[8192];
   long need = -1;
   size_t hdr_end = 0;
   for (;;) {
-    ssize_t n = recv(fd, tmp, sizeof(tmp), 0);
+    long n = recv(fd, tmp, sizeof(tmp), 0);
     if (n <= 0)
       break;
     cst_buf_append(&req, tmp, (size_t)n);
@@ -230,23 +227,23 @@ static void *conn_main(void *p) {
   if (hdr_end)
     handle(fd, req.buf + hdr_end);
   cst_buf_free(&req);
-  close(fd);
+  test_sock_close(fd);
   return NULL;
 }
 
-static int g_lfd;
+static test_sock_t g_lfd;
 
 static void *server_main(void *p) {
   (void)p;
   for (;;) {
-    int fd = accept(g_lfd, NULL, NULL);
-    if (fd < 0)
+    test_sock_t fd = accept(g_lfd, NULL, NULL);
+    if (fd == TEST_BAD_SOCK)
       return NULL;
     pthread_t th;
     if (pthread_create(&th, NULL, conn_main, (void *)(intptr_t)fd) == 0)
       pthread_detach(th);
     else
-      close(fd);
+      test_sock_close(fd);
   }
 }
 
@@ -282,10 +279,10 @@ static void put(const char *root, const char *rel, const char *text) {
   for (char *q = p + strlen(root) + 1; *q; q++)
     if (*q == '/') {
       *q = 0;
-      mkdir(p, 0755);
+      test_mkdir(p, 0755);
       *q = '/';
     }
-  FILE *fp = fopen(p, "w");
+  FILE *fp = fopen(p, "wb");
   if (fp) {
     fputs(text, fp);
     fclose(fp);
@@ -293,13 +290,13 @@ static void put(const char *root, const char *rel, const char *text) {
 }
 
 static void *cancel_later(void *p) {
-  usleep(800 * 1000);
+  test_sleep_ms(800);
   cst_agent_request_cancel(p);
   return NULL;
 }
 
 int main(void) {
-  signal(SIGPIPE, SIG_IGN);
+  test_sock_init();
   curl_global_init(CURL_GLOBAL_DEFAULT);
   g_lfd = socket(AF_INET, SOCK_STREAM, 0);
   struct sockaddr_in addr;
@@ -316,10 +313,10 @@ int main(void) {
   pthread_t srv;
   pthread_create(&srv, NULL, server_main, NULL);
 
-  char root[256], ws[300];
-  snprintf(root, sizeof(root), "/tmp/cst-sub-%d", (int)getpid());
+  char root[600], ws[700];
+  if (test_tmpdir(root, sizeof(root), "cst-sub") != 0)
+    return 1;
   snprintf(ws, sizeof(ws), "%s/ws", root);
-  mkdir(root, 0755);
   setenv("XDG_CONFIG_HOME", root, 1);
   put(root, "ws/a.txt", "alpha\n");
   put(root, "ws/.agent/agents/reviewer.md",
@@ -470,11 +467,9 @@ int main(void) {
   CHECK(cst_subagent_list(ws, "parent1", recs, 8) == 0,
         "delete removes sub-agent transcripts");
 
-  char cmd[400];
-  snprintf(cmd, sizeof(cmd), "rm -rf %s", root);
-  if (system(cmd) != 0)
+  if (test_rmrf(root) != 0)
     fprintf(stderr, "note: cleanup failed\n");
-  close(g_lfd);
+  test_sock_close(g_lfd);
   if (nfail) {
     fprintf(stderr, "test_subagent: %d failure(s)\n", nfail);
     return 1;
diff --git a/tests/test_tools_fs.c b/tests/test_tools_fs.c
index 3c02949..906e307 100644
--- a/tests/test_tools_fs.c
+++ b/tests/test_tools_fs.c
@@ -12,6 +12,8 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
+#include "cst_test_util.h"
+
 static int nfail;
 
 #define EXPECT(cond, msg)                                                      \
@@ -98,17 +100,19 @@ static int run(cst_tool_ctx_t *ctx, ctl_tool_call_t c, cst_tool_result_t *r) {
 static void reset(cst_tool_result_t *r) { cst_tool_result_free(r); }
 
 int main(void) {
-  snprintf(g_ws, sizeof(g_ws), "/tmp/cst-tools-test-%d", (int)getpid());
-  mkdir(g_ws, 0755);
+  if (test_tmpdir(g_ws, sizeof(g_ws), "cst-tools-test") != 0) {
+    perror("tmpdir");
+    return 1;
+  }
   char p[512];
   snprintf(p, sizeof(p), "%s/src", g_ws);
-  mkdir(p, 0755);
+  test_mkdir(p, 0755);
   snprintf(p, sizeof(p), "%s/src/deep", g_ws);
-  mkdir(p, 0755);
+  test_mkdir(p, 0755);
   snprintf(p, sizeof(p), "%s/node_modules", g_ws);
-  mkdir(p, 0755);
+  test_mkdir(p, 0755);
   snprintf(p, sizeof(p), "%s/build", g_ws);
-  mkdir(p, 0755);
+  test_mkdir(p, 0755);
   wfile("src/main.c", "#include <stdio.h>\nint main(void) {\n  int x = 42;\n"
                       "  printf(\"%d\\n\", x);\n  return 0;\n}\n");
   wfile("src/deep/util.c", "int add(int a, int b) { return a + b; }\n"
@@ -119,7 +123,7 @@ int main(void) {
   wfile(".gitignore", "build/\n*.log\n");
   wfile("run.log", "int add in log\n");
   {
-    FILE *fp = fopen(strcat(strcpy(p, g_ws), "/lines.txt"), "w");
+    FILE *fp = fopen(strcat(strcpy(p, g_ws), "/lines.txt"), "wb");
     for (int i = 1; i <= 100; i++)
       fprintf(fp, "line %d\n", i);
     fclose(fp);
@@ -410,9 +414,7 @@ int main(void) {
            "patch targets");
   }
 
-  char cmd[400];
-  snprintf(cmd, sizeof(cmd), "rm -rf %s", g_ws);
-  if (system(cmd) != 0)
+  if (test_rmrf(g_ws) != 0)
     fprintf(stderr, "note: cleanup failed\n");
   if (nfail) {
     fprintf(stderr, "test_tools_fs: %d failure(s)\n", nfail);
diff --git a/tests/test_undo.c b/tests/test_undo.c
index 3d7b6f2..5ef0e59 100644
--- a/tests/test_undo.c
+++ b/tests/test_undo.c
@@ -10,6 +10,7 @@
 #include <string.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include "cst_test_util.h"
 
 static int nfail;
 
@@ -81,9 +82,9 @@ static void test_undo(void) {
   EXPECT(cst_undo_snapshot(g_ws, sid, "t3", "d/e/f.txt") == 0, "snap nested");
   char p[512];
   snprintf(p, sizeof(p), "%s/d", g_ws);
-  mkdir(p, 0755);
+  test_mkdir(p, 0755);
   snprintf(p, sizeof(p), "%s/d/e", g_ws);
-  mkdir(p, 0755);
+  test_mkdir(p, 0755);
   wfile("d/e/f.txt", "x");
   EXPECT(cst_undo_restore_last(g_ws, sid, rep, sizeof(rep)) == 0, "undo t3");
   EXPECT(rfile_eq("d/e/f.txt", NULL), "nested file removed");
@@ -146,7 +147,7 @@ static void test_store(void) {
   EXPECT(cst_agent_store_path_for_id(g_ws, "20260101-000000-abcd", path,
                                      sizeof(path)) == 0,
          "path for id");
-  FILE *fp = fopen(path, "w");
+  FILE *fp = fopen(path, "wb");
   EXPECT(fp != NULL, "create session file");
   if (fp) {
     fputs("{\"role\":\"system\",\"content\":\"sys\"}\n", fp);
@@ -174,17 +175,14 @@ static void test_store(void) {
 }
 
 int main(void) {
-  snprintf(g_ws, sizeof(g_ws), "/tmp/cst_test_undo_XXXXXX");
-  if (!mkdtemp(g_ws)) {
+  if (test_tmpdir(g_ws, sizeof(g_ws), "cst_test_undo") != 0) {
     perror("mkdtemp");
     return 1;
   }
   test_undo();
   test_perms();
   test_store();
-  char cmd[512];
-  snprintf(cmd, sizeof(cmd), "rm -rf '%s'", g_ws);
-  if (system(cmd) != 0)
+  if (test_rmrf(g_ws) != 0)
     fprintf(stderr, "warning: cleanup failed\n");
   if (nfail) {
     fprintf(stderr, "test_undo: %d failure(s)\n", nfail);
diff --git a/tests/test_win_utf8.c b/tests/test_win_utf8.c
new file mode 100644
index 0000000..bd43e62
--- /dev/null
+++ b/tests/test_win_utf8.c
@@ -0,0 +1,238 @@
+/* UTF-8 everywhere: Chinese workspace and file names through the file
+ * tools and the shell, CRLF and BOM files edited by apply_patch, write_file
+ * and edit_file without losing their style, and (Windows) child output in
+ * the OEM code page turned into UTF-8. */
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include "cst_agent.h"
+#include "cst_util.h"
+#include "os_compat.h"
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "cst_test_util.h"
+
+static int nfail;
+
+#define EXPECT(cond, msg)                                                      \
+  do {                                                                         \
+    if (!(cond)) {                                                             \
+      fprintf(stderr, "FAIL %s:%d: %s\n", __FILE__, __LINE__, msg);            \
+      nfail++;                                                                 \
+    }                                                                          \
+  } while (0)
+
+static char g_ws[1100];
+
+/* tool(name, key, value, key, value, ..., NULL) */
+static int tool(cst_tool_result_t *r, const char *name, ...) {
+  ctl_tool_call_t c;
+  memset(&c, 0, sizeof(c));
+  snprintf(c.id, sizeof(c.id), "t");
+  snprintf(c.name, sizeof(c.name), "%s", name);
+  va_list ap;
+  va_start(ap, name);
+  const char *k;
+  while ((k = va_arg(ap, const char *)) != NULL) {
+    const char *v = va_arg(ap, const char *);
+    snprintf(c.args[c.nargs].key, sizeof(c.args[c.nargs].key), "%s", k);
+    c.args[c.nargs].value = (char *)v;
+    c.args[c.nargs].value_len = strlen(v);
+    c.nargs++;
+  }
+  va_end(ap);
+  memset(r, 0, sizeof(*r));
+  cst_tool_dispatch(g_ws, &c, r);
+  return r->exit_code;
+}
+
+static char *slurp(const char *rel, size_t *n) {
+  char p[1200];
+  snprintf(p, sizeof(p), "%s/%s", g_ws, rel);
+  FILE *f = fopen(p, "rb");
+  if (!f)
+    return NULL;
+  char *b = malloc(1 << 16);
+  *n = b ? fread(b, 1, (1 << 16) - 1, f) : 0;
+  if (b)
+    b[*n] = 0;
+  fclose(f);
+  return b;
+}
+
+static void spit(const char *rel, const char *s) {
+  char p[1200];
+  snprintf(p, sizeof(p), "%s/%s", g_ws, rel);
+  FILE *f = fopen(p, "wb");
+  if (f) {
+    fputs(s, f);
+    fclose(f);
+  }
+}
+
+static int file_is(const char *rel, const char *want) {
+  size_t n = 0;
+  char *b = slurp(rel, &n);
+  int ok = b && n == strlen(want) && memcmp(b, want, n) == 0;
+  if (!ok)
+    fprintf(stderr, "  %s is \"%s\"\n", rel, b ? b : "(missing)");
+  free(b);
+  return ok;
+}
+
+static void test_patch_buffer(void) {
+  char *out = NULL, err[256];
+  size_t n = 0;
+  int nh = 0;
+  const char *crlf = "a\r\nb\r\nc\r\n";
+  const char *hunk = "@@ -1,3 +1,3 @@\n a\n-b\n+B\n c\n";
+  EXPECT(cst_patch_apply_buffer(crlf, strlen(crlf), hunk, strlen(hunk), &out,
+                                &n, &nh, err, sizeof(err)) == 0,
+         "LF hunk applies to a CRLF file");
+  EXPECT(out && strcmp(out, "a\r\nB\r\nc\r\n") == 0, "CRLF kept");
+  free(out);
+
+  const char *bom = "\xEF\xBB\xBF" "first\nsecond\n";
+  const char *h2 = "@@ -1,2 +1,2 @@\n-first\n+FIRST\n second\n";
+  EXPECT(cst_patch_apply_buffer(bom, strlen(bom), h2, strlen(h2), &out, &n,
+                                &nh, err, sizeof(err)) == 0,
+         "first line matches past the BOM");
+  EXPECT(out && strcmp(out, "\xEF\xBB\xBF" "FIRST\nsecond\n") == 0,
+         "BOM kept");
+  free(out);
+
+  const char *lf = "x\ny\n";
+  const char *h3 = "@@ -1,2 +1,3 @@\n x\n+中文\n y\n";
+  EXPECT(cst_patch_apply_buffer(lf, strlen(lf), h3, strlen(h3), &out, &n, &nh,
+                                err, sizeof(err)) == 0 &&
+             out && strcmp(out, "x\n中文\ny\n") == 0,
+         "LF file stays LF");
+  free(out);
+
+  EXPECT(cst_text_is_crlf("a\r\nb\r\n", 6), "is_crlf");
+  EXPECT(!cst_text_is_crlf("a\r\nb\n", 5), "mixed is not crlf");
+  EXPECT(!cst_text_is_crlf("ab", 2), "no newline is not crlf");
+}
+
+static void test_tools(void) {
+  cst_tool_result_t r;
+  /* Chinese names through write/read/list/glob/grep */
+  EXPECT(tool(&r, "write_file", "path", "目录/文件.txt", "content",
+              "你好，世界\n第二行\n", NULL) == 0,
+         "write_file with a Chinese path");
+  cst_tool_result_free(&r);
+  EXPECT(tool(&r, "read_file", "path", "目录/文件.txt", NULL) == 0 && r.out &&
+             strstr(r.out, "你好，世界"),
+         "read_file with a Chinese path");
+  cst_tool_result_free(&r);
+  EXPECT(tool(&r, "list_dir", "path", "目录", NULL) == 0 && r.out &&
+             strstr(r.out, "文件.txt"),
+         "list_dir shows the Chinese name");
+  cst_tool_result_free(&r);
+  EXPECT(tool(&r, "glob", "pattern", "**/*.txt", NULL) == 0 && r.out &&
+             strstr(r.out, "目录/文件.txt"),
+         "glob finds the Chinese name");
+  cst_tool_result_free(&r);
+  EXPECT(tool(&r, "grep", "pattern", "世界", NULL) == 0 && r.out &&
+             strstr(r.out, "文件.txt"),
+         "grep matches Chinese text");
+  cst_tool_result_free(&r);
+
+  /* CRLF + BOM file */
+  spit("win.txt", "\xEF\xBB\xBFone\r\ntwo\r\nthree\r\n");
+  EXPECT(tool(&r, "read_file", "path", "win.txt", NULL) == 0 && r.out &&
+             strcmp(r.out, "one\ntwo\nthree\n") == 0,
+         "read_file hides BOM and CR");
+  cst_tool_result_free(&r);
+  EXPECT(tool(&r, "edit_file", "path", "win.txt", "old_string", "two",
+              "new_string", "二\n2", NULL) == 0,
+         "edit_file single-line match");
+  cst_tool_result_free(&r);
+  EXPECT(file_is("win.txt", "\xEF\xBB\xBFone\r\n二\r\n2\r\nthree\r\n"),
+         "edit_file inserts CRLF");
+  EXPECT(tool(&r, "edit_file", "path", "win.txt", "old_string", "one\n二",
+              "new_string", "壹\n贰", NULL) == 0,
+         "edit_file multi-line LF match");
+  cst_tool_result_free(&r);
+  EXPECT(file_is("win.txt", "\xEF\xBB\xBF壹\r\n贰\r\n2\r\nthree\r\n"),
+         "edit_file keeps CRLF and BOM");
+  EXPECT(tool(&r, "apply_patch", "patch",
+              "--- a/win.txt\n+++ b/win.txt\n@@ -3,2 +3,2 @@\n 2\n-three\n"
+              "+叁\n",
+              NULL) == 0,
+         "apply_patch on a CRLF file");
+  if (r.exit_code)
+    fprintf(stderr, "  apply_patch: %s\n", r.out ? r.out : "");
+  cst_tool_result_free(&r);
+  EXPECT(file_is("win.txt", "\xEF\xBB\xBF壹\r\n贰\r\n2\r\n叁\r\n"),
+         "apply_patch keeps CRLF and BOM");
+  EXPECT(tool(&r, "write_file", "path", "win.txt", "content", "new\ntext\n",
+              NULL) == 0,
+         "write_file over a CRLF file");
+  cst_tool_result_free(&r);
+  EXPECT(file_is("win.txt", "\xEF\xBB\xBFnew\r\ntext\r\n"),
+         "write_file keeps CRLF and BOM");
+  EXPECT(tool(&r, "write_file", "path", "new.txt", "content", "lf\n", NULL) ==
+             0 &&
+             file_is("new.txt", "lf\n"),
+         "new files are LF without BOM");
+  cst_tool_result_free(&r);
+
+  /* the shell sees and prints UTF-8 */
+  EXPECT(tool(&r, "run_shell", "cmd", "cat 目录/文件.txt && echo 完成", NULL) ==
+                 0 &&
+             r.out && strstr(r.out, "你好，世界") && strstr(r.out, "完成"),
+         "run_shell with Chinese arguments and output");
+  if (!r.out || !strstr(r.out, "完成"))
+    fprintf(stderr, "  run_shell: %s\n", r.out ? r.out : "");
+  cst_tool_result_free(&r);
+}
+
+#ifdef _WIN32
+static void test_oem_output(void) {
+  /* "中文" in GBK */
+  const char gbk[] = "\xD6\xD0\xCE\xC4\r\n";
+  size_t n = 0;
+  char *u = os_output_to_utf8(gbk, sizeof(gbk) - 1, &n);
+  wchar_t b[8] = L"0";
+  GetLocaleInfoW(LOCALE_SYSTEM_DEFAULT, LOCALE_IDEFAULTCODEPAGE, b, 8);
+  unsigned oem = (unsigned)wcstoul(b, NULL, 10);
+  if (oem == 936)
+    EXPECT(u && strstr(u, "中文"), "GBK output decoded on a 936 system");
+  else
+    EXPECT(u != NULL, "non-UTF-8 output is decoded");
+  free(u);
+  EXPECT(os_output_to_utf8("中文", strlen("中文"), &n) == NULL,
+         "UTF-8 output left alone");
+  printf("test_win_utf8: ACP %u, OEM %u, system OEM %u, console %u\n",
+         GetACP(), GetOEMCP(), oem, GetConsoleOutputCP());
+  EXPECT(GetACP() == CP_UTF8, "manifest makes UTF-8 the process code page");
+}
+#endif
+
+int main(void) {
+  os_console_init();
+  char base[1024];
+  if (test_tmpdir(base, sizeof(base), "cst-utf8") != 0) {
+    perror("tmpdir");
+    return 1;
+  }
+  snprintf(g_ws, sizeof(g_ws), "%s/项目 空格", base);
+  test_mkdir(g_ws, 0755);
+  test_patch_buffer();
+  test_tools();
+#ifdef _WIN32
+  test_oem_output();
+#endif
+  test_rmrf(base);
+  if (nfail) {
+    fprintf(stderr, "test_win_utf8: %d failure(s)\n", nfail);
+    return 1;
+  }
+  puts("test_win_utf8: OK");
+  return 0;
+}
diff --git a/third_party/busybox/LICENSE.busybox b/third_party/busybox/LICENSE.busybox
index aa3aaca..ab2aa68 100644
--- a/third_party/busybox/LICENSE.busybox
+++ b/third_party/busybox/LICENSE.busybox
@@ -1,2 +1,3 @@
-BusyBox is GPLv2. Source: https://github.com/rmyorston/busybox-w32
-Upstream BusyBox: https://github.com/mirror/busybox
+BusyBox is GPLv2. This busybox.exe is busybox-w32 (9b50a1e, Unicode build):
+https://github.com/rmyorston/busybox-w32
+Upstream BusyBox: https://busybox.net/
diff --git a/vendor/tre-regex/COPYRIGHT.musl b/vendor/tre-regex/COPYRIGHT.musl
new file mode 100644
index 0000000..c1628e9
--- /dev/null
+++ b/vendor/tre-regex/COPYRIGHT.musl
@@ -0,0 +1,193 @@
+musl as a whole is licensed under the following standard MIT license:
+
+----------------------------------------------------------------------
+Copyright © 2005-2020 Rich Felker, et al.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+----------------------------------------------------------------------
+
+Authors/contributors include:
+
+A. Wilcox
+Ada Worcester
+Alex Dowad
+Alex Suykov
+Alexander Monakov
+Andre McCurdy
+Andrew Kelley
+Anthony G. Basile
+Aric Belsito
+Arvid Picciani
+Bartosz Brachaczek
+Benjamin Peterson
+Bobby Bingham
+Boris Brezillon
+Brent Cook
+Chris Spiegel
+Clément Vasseur
+Daniel Micay
+Daniel Sabogal
+Daurnimator
+David Carlier
+David Edelsohn
+Denys Vlasenko
+Dmitry Ivanov
+Dmitry V. Levin
+Drew DeVault
+Emil Renner Berthing
+Fangrui Song
+Felix Fietkau
+Felix Janda
+Gianluca Anzolin
+Hauke Mehrtens
+He X
+Hiltjo Posthuma
+Isaac Dunham
+Jaydeep Patil
+Jens Gustedt
+Jeremy Huntwork
+Jo-Philipp Wich
+Joakim Sindholt
+John Spencer
+Julien Ramseier
+Justin Cormack
+Kaarle Ritvanen
+Khem Raj
+Kylie McClain
+Leah Neukirchen
+Luca Barbato
+Luka Perkov
+M Farkas-Dyck (Strake)
+Mahesh Bodapati
+Markus Wichmann
+Masanori Ogino
+Michael Clark
+Michael Forney
+Mikhail Kremnyov
+Natanael Copa
+Nicholas J. Kain
+orc
+Pascal Cuoq
+Patrick Oppenlander
+Petr Hosek
+Petr Skocik
+Pierre Carrier
+Reini Urban
+Rich Felker
+Richard Pennington
+Ryan Fairfax
+Samuel Holland
+Segev Finer
+Shiz
+sin
+Solar Designer
+Stefan Kristiansson
+Stefan O'Rear
+Szabolcs Nagy
+Timo Teräs
+Trutz Behn
+Valentin Ochs
+Will Dietz
+William Haddon
+William Pitcock
+
+Portions of this software are derived from third-party works licensed
+under terms compatible with the above MIT license:
+
+The TRE regular expression implementation (src/regex/reg* and
+src/regex/tre*) is Copyright © 2001-2008 Ville Laurikari and licensed
+under a 2-clause BSD license (license text in the source files). The
+included version has been heavily modified by Rich Felker in 2012, in
+the interests of size, simplicity, and namespace cleanliness.
+
+Much of the math library code (src/math/* and src/complex/*) is
+Copyright © 1993,2004 Sun Microsystems or
+Copyright © 2003-2011 David Schultz or
+Copyright © 2003-2009 Steven G. Kargl or
+Copyright © 2003-2009 Bruce D. Evans or
+Copyright © 2008 Stephen L. Moshier or
+Copyright © 2017-2018 Arm Limited
+and labelled as such in comments in the individual source files. All
+have been licensed under extremely permissive terms.
+
+The ARM memcpy code (src/string/arm/memcpy.S) is Copyright © 2008
+The Android Open Source Project and is licensed under a two-clause BSD
+license. It was taken from Bionic libc, used on Android.
+
+The AArch64 memcpy and memset code (src/string/aarch64/*) are
+Copyright © 1999-2019, Arm Limited.
+
+The implementation of DES for crypt (src/crypt/crypt_des.c) is
+Copyright © 1994 David Burren. It is licensed under a BSD license.
+
+The implementation of blowfish crypt (src/crypt/crypt_blowfish.c) was
+originally written by Solar Designer and placed into the public
+domain. The code also comes with a fallback permissive license for use
+in jurisdictions that may not recognize the public domain.
+
+The smoothsort implementation (src/stdlib/qsort.c) is Copyright © 2011
+Valentin Ochs and is licensed under an MIT-style license.
+
+The x86_64 port was written by Nicholas J. Kain and is licensed under
+the standard MIT terms.
+
+The mips and microblaze ports were originally written by Richard
+Pennington for use in the ellcc project. The original code was adapted
+by Rich Felker for build system and code conventions during upstream
+integration. It is licensed under the standard MIT terms.
+
+The mips64 port was contributed by Imagination Technologies and is
+licensed under the standard MIT terms.
+
+The powerpc port was also originally written by Richard Pennington,
+and later supplemented and integrated by John Spencer. It is licensed
+under the standard MIT terms.
+
+All other files which have no copyright comments are original works
+produced specifically for use as part of this library, written either
+by Rich Felker, the main author of the library, or by one or more
+contibutors listed above. Details on authorship of individual files
+can be found in the git version control history of the project. The
+omission of copyright and license comments in each file is in the
+interest of source tree size.
+
+In addition, permission is hereby granted for all public header files
+(include/* and arch/*/bits/*) and crt files intended to be linked into
+applications (crt/*, ldso/dlstart.c, and arch/*/crt_arch.h) to omit
+the copyright notice and permission notice otherwise required by the
+license, and to use these files without any requirement of
+attribution. These files include substantial contributions from:
+
+Bobby Bingham
+John Spencer
+Nicholas J. Kain
+Rich Felker
+Richard Pennington
+Stefan Kristiansson
+Szabolcs Nagy
+
+all of whom have explicitly granted such permission.
+
+This file previously contained text expressing a belief that most of
+the files covered by the above exception were sufficiently trivial not
+to be subject to copyright, resulting in confusion over whether it
+negated the permissions granted in the license. In the spirit of
+permissive licensing, and of not having licensing issues being an
+obstacle to adoption, that text has been removed.
diff --git a/vendor/tre-regex/regcomp.c b/vendor/tre-regex/regcomp.c
new file mode 100644
index 0000000..529fc4d
--- /dev/null
+++ b/vendor/tre-regex/regcomp.c
@@ -0,0 +1,2953 @@
+/*
+  regcomp.c - TRE POSIX compatible regex compilation functions.
+
+  Copyright (c) 2001-2009 Ville Laurikari <vl@iki.fi>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions
+  are met:
+
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS
+  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+  A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
+  HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+*/
+
+#include <string.h>
+#include <stdlib.h>
+#include "regex.h"
+#include <limits.h>
+#include <stdint.h>
+#include <ctype.h>
+
+#include "tre.h"
+
+#include <assert.h>
+
+/***********************************************************************
+ from tre-compile.h
+***********************************************************************/
+
+typedef struct {
+  int position;
+  int code_min;
+  int code_max;
+  int *tags;
+  int assertions;
+  tre_ctype_t class;
+  tre_ctype_t *neg_classes;
+  int backref;
+} tre_pos_and_tags_t;
+
+
+/***********************************************************************
+ from tre-ast.c and tre-ast.h
+***********************************************************************/
+
+/* The different AST node types. */
+typedef enum {
+  LITERAL,
+  CATENATION,
+  ITERATION,
+  UNION
+} tre_ast_type_t;
+
+/* Special subtypes of TRE_LITERAL. */
+#define EMPTY	  -1   /* Empty leaf (denotes empty string). */
+#define ASSERTION -2   /* Assertion leaf. */
+#define TAG	  -3   /* Tag leaf. */
+#define BACKREF	  -4   /* Back reference leaf. */
+
+#define IS_SPECIAL(x)	((x)->code_min < 0)
+#define IS_EMPTY(x)	((x)->code_min == EMPTY)
+#define IS_ASSERTION(x) ((x)->code_min == ASSERTION)
+#define IS_TAG(x)	((x)->code_min == TAG)
+#define IS_BACKREF(x)	((x)->code_min == BACKREF)
+
+
+/* A generic AST node.  All AST nodes consist of this node on the top
+   level with `obj' pointing to the actual content. */
+typedef struct {
+  tre_ast_type_t type;   /* Type of the node. */
+  void *obj;             /* Pointer to actual node. */
+  int nullable;
+  int submatch_id;
+  int num_submatches;
+  int num_tags;
+  tre_pos_and_tags_t *firstpos;
+  tre_pos_and_tags_t *lastpos;
+} tre_ast_node_t;
+
+
+/* A "literal" node.  These are created for assertions, back references,
+   tags, matching parameter settings, and all expressions that match one
+   character. */
+typedef struct {
+  long code_min;
+  long code_max;
+  int position;
+  tre_ctype_t class;
+  tre_ctype_t *neg_classes;
+} tre_literal_t;
+
+/* A "catenation" node.	 These are created when two regexps are concatenated.
+   If there are more than one subexpressions in sequence, the `left' part
+   holds all but the last, and `right' part holds the last subexpression
+   (catenation is left associative). */
+typedef struct {
+  tre_ast_node_t *left;
+  tre_ast_node_t *right;
+} tre_catenation_t;
+
+/* An "iteration" node.	 These are created for the "*", "+", "?", and "{m,n}"
+   operators. */
+typedef struct {
+  /* Subexpression to match. */
+  tre_ast_node_t *arg;
+  /* Minimum number of consecutive matches. */
+  int min;
+  /* Maximum number of consecutive matches. */
+  int max;
+  /* If 0, match as many characters as possible, if 1 match as few as
+     possible.	Note that this does not always mean the same thing as
+     matching as many/few repetitions as possible. */
+  unsigned int minimal:1;
+} tre_iteration_t;
+
+/* An "union" node.  These are created for the "|" operator. */
+typedef struct {
+  tre_ast_node_t *left;
+  tre_ast_node_t *right;
+} tre_union_t;
+
+
+static tre_ast_node_t *
+tre_ast_new_node(tre_mem_t mem, int type, void *obj)
+{
+	tre_ast_node_t *node = tre_mem_calloc(mem, sizeof *node);
+	if (!node || !obj)
+		return 0;
+	node->obj = obj;
+	node->type = type;
+	node->nullable = -1;
+	node->submatch_id = -1;
+	return node;
+}
+
+static tre_ast_node_t *
+tre_ast_new_literal(tre_mem_t mem, int code_min, int code_max, int position)
+{
+	tre_ast_node_t *node;
+	tre_literal_t *lit;
+
+	lit = tre_mem_calloc(mem, sizeof *lit);
+	node = tre_ast_new_node(mem, LITERAL, lit);
+	if (!node)
+		return 0;
+	lit->code_min = code_min;
+	lit->code_max = code_max;
+	lit->position = position;
+	return node;
+}
+
+static tre_ast_node_t *
+tre_ast_new_iter(tre_mem_t mem, tre_ast_node_t *arg, int min, int max, int minimal)
+{
+	tre_ast_node_t *node;
+	tre_iteration_t *iter;
+
+	iter = tre_mem_calloc(mem, sizeof *iter);
+	node = tre_ast_new_node(mem, ITERATION, iter);
+	if (!node)
+		return 0;
+	iter->arg = arg;
+	iter->min = min;
+	iter->max = max;
+	iter->minimal = minimal;
+	node->num_submatches = arg->num_submatches;
+	return node;
+}
+
+static tre_ast_node_t *
+tre_ast_new_union(tre_mem_t mem, tre_ast_node_t *left, tre_ast_node_t *right)
+{
+	tre_ast_node_t *node;
+	tre_union_t *un;
+
+	if (!left)
+		return right;
+	un = tre_mem_calloc(mem, sizeof *un);
+	node = tre_ast_new_node(mem, UNION, un);
+	if (!node || !right)
+		return 0;
+	un->left = left;
+	un->right = right;
+	node->num_submatches = left->num_submatches + right->num_submatches;
+	return node;
+}
+
+static tre_ast_node_t *
+tre_ast_new_catenation(tre_mem_t mem, tre_ast_node_t *left, tre_ast_node_t *right)
+{
+	tre_ast_node_t *node;
+	tre_catenation_t *cat;
+
+	if (!left)
+		return right;
+	cat = tre_mem_calloc(mem, sizeof *cat);
+	node = tre_ast_new_node(mem, CATENATION, cat);
+	if (!node)
+		return 0;
+	cat->left = left;
+	cat->right = right;
+	node->num_submatches = left->num_submatches + right->num_submatches;
+	return node;
+}
+
+
+/***********************************************************************
+ from tre-stack.c and tre-stack.h
+***********************************************************************/
+
+typedef struct tre_stack_rec tre_stack_t;
+
+/* Creates a new stack object.	`size' is initial size in bytes, `max_size'
+   is maximum size, and `increment' specifies how much more space will be
+   allocated with realloc() if all space gets used up.	Returns the stack
+   object or NULL if out of memory. */
+static tre_stack_t *
+tre_stack_new(int size, int max_size, int increment);
+
+/* Frees the stack object. */
+static void
+tre_stack_destroy(tre_stack_t *s);
+
+/* Returns the current number of objects in the stack. */
+static int
+tre_stack_num_objects(tre_stack_t *s);
+
+/* Each tre_stack_push_*(tre_stack_t *s, <type> value) function pushes
+   `value' on top of stack `s'.  Returns REG_ESPACE if out of memory.
+   This tries to realloc() more space before failing if maximum size
+   has not yet been reached.  Returns REG_OK if successful. */
+#define declare_pushf(typetag, type)					      \
+  static reg_errcode_t tre_stack_push_ ## typetag(tre_stack_t *s, type value)
+
+declare_pushf(voidptr, void *);
+declare_pushf(int, int);
+
+/* Each tre_stack_pop_*(tre_stack_t *s) function pops the topmost
+   element off of stack `s' and returns it.  The stack must not be
+   empty. */
+#define declare_popf(typetag, type)		  \
+  static type tre_stack_pop_ ## typetag(tre_stack_t *s)
+
+declare_popf(voidptr, void *);
+declare_popf(int, int);
+
+/* Just to save some typing. */
+#define STACK_PUSH(s, typetag, value)					      \
+  do									      \
+    {									      \
+      status = tre_stack_push_ ## typetag(s, value);			      \
+    }									      \
+  while (/*CONSTCOND*/0)
+
+#define STACK_PUSHX(s, typetag, value)					      \
+  {									      \
+    status = tre_stack_push_ ## typetag(s, value);			      \
+    if (status != REG_OK)						      \
+      break;								      \
+  }
+
+#define STACK_PUSHR(s, typetag, value)					      \
+  {									      \
+    reg_errcode_t _status;						      \
+    _status = tre_stack_push_ ## typetag(s, value);			      \
+    if (_status != REG_OK)						      \
+      return _status;							      \
+  }
+
+union tre_stack_item {
+  void *voidptr_value;
+  int int_value;
+};
+
+struct tre_stack_rec {
+  int size;
+  int max_size;
+  int increment;
+  int ptr;
+  union tre_stack_item *stack;
+};
+
+
+static tre_stack_t *
+tre_stack_new(int size, int max_size, int increment)
+{
+  tre_stack_t *s;
+
+  s = xmalloc(sizeof(*s));
+  if (s != NULL)
+    {
+      s->stack = xmalloc(sizeof(*s->stack) * size);
+      if (s->stack == NULL)
+	{
+	  xfree(s);
+	  return NULL;
+	}
+      s->size = size;
+      s->max_size = max_size;
+      s->increment = increment;
+      s->ptr = 0;
+    }
+  return s;
+}
+
+static void
+tre_stack_destroy(tre_stack_t *s)
+{
+  xfree(s->stack);
+  xfree(s);
+}
+
+static int
+tre_stack_num_objects(tre_stack_t *s)
+{
+  return s->ptr;
+}
+
+static reg_errcode_t
+tre_stack_push(tre_stack_t *s, union tre_stack_item value)
+{
+  if (s->ptr < s->size)
+    {
+      s->stack[s->ptr] = value;
+      s->ptr++;
+    }
+  else
+    {
+      if (s->size >= s->max_size)
+	{
+	  return REG_ESPACE;
+	}
+      else
+	{
+	  union tre_stack_item *new_buffer;
+	  int new_size;
+	  new_size = s->size + s->increment;
+	  if (new_size > s->max_size)
+	    new_size = s->max_size;
+	  new_buffer = xrealloc(s->stack, sizeof(*new_buffer) * new_size);
+	  if (new_buffer == NULL)
+	    {
+	      return REG_ESPACE;
+	    }
+	  assert(new_size > s->size);
+	  s->size = new_size;
+	  s->stack = new_buffer;
+	  tre_stack_push(s, value);
+	}
+    }
+  return REG_OK;
+}
+
+#define define_pushf(typetag, type)  \
+  declare_pushf(typetag, type) {     \
+    union tre_stack_item item;	     \
+    item.typetag ## _value = value;  \
+    return tre_stack_push(s, item);  \
+}
+
+define_pushf(int, int)
+define_pushf(voidptr, void *)
+
+#define define_popf(typetag, type)		    \
+  declare_popf(typetag, type) {			    \
+    return s->stack[--s->ptr].typetag ## _value;    \
+  }
+
+define_popf(int, int)
+define_popf(voidptr, void *)
+
+
+/***********************************************************************
+ from tre-parse.c and tre-parse.h
+***********************************************************************/
+
+/* Parse context. */
+typedef struct {
+	/* Memory allocator. The AST is allocated using this. */
+	tre_mem_t mem;
+	/* Stack used for keeping track of regexp syntax. */
+	tre_stack_t *stack;
+	/* The parsed node after a parse function returns. */
+	tre_ast_node_t *n;
+	/* Position in the regexp pattern after a parse function returns. */
+	const char *s;
+	/* The first character of the last subexpression parsed. */
+	const char *start;
+	/* Current submatch ID. */
+	int submatch_id;
+	/* Current position (number of literal). */
+	int position;
+	/* The highest back reference or -1 if none seen so far. */
+	int max_backref;
+	/* Compilation flags. */
+	int cflags;
+} tre_parse_ctx_t;
+
+/* Some macros for expanding \w, \s, etc. */
+static const struct {
+	char c;
+	const char *expansion;
+} tre_macros[] = {
+	{'t', "\t"}, {'n', "\n"}, {'r', "\r"},
+	{'f', "\f"}, {'a', "\a"}, {'e', "\033"},
+	{'w', "[[:alnum:]_]"}, {'W', "[^[:alnum:]_]"}, {'s', "[[:space:]]"},
+	{'S', "[^[:space:]]"}, {'d', "[[:digit:]]"}, {'D', "[^[:digit:]]"},
+	{ 0, 0 }
+};
+
+/* Expands a macro delimited by `regex' and `regex_end' to `buf', which
+   must have at least `len' items.  Sets buf[0] to zero if the there
+   is no match in `tre_macros'. */
+static const char *tre_expand_macro(const char *s)
+{
+	int i;
+	for (i = 0; tre_macros[i].c && tre_macros[i].c != *s; i++);
+	return tre_macros[i].expansion;
+}
+
+static int
+tre_compare_lit(const void *a, const void *b)
+{
+	const tre_literal_t *const *la = a;
+	const tre_literal_t *const *lb = b;
+	/* assumes the range of valid code_min is < INT_MAX */
+	return la[0]->code_min - lb[0]->code_min;
+}
+
+struct literals {
+	tre_mem_t mem;
+	tre_literal_t **a;
+	int len;
+	int cap;
+};
+
+static tre_literal_t *tre_new_lit(struct literals *p)
+{
+	tre_literal_t **a;
+	if (p->len >= p->cap) {
+		if (p->cap >= 1<<15)
+			return 0;
+		p->cap *= 2;
+		a = xrealloc(p->a, p->cap * sizeof *p->a);
+		if (!a)
+			return 0;
+		p->a = a;
+	}
+	a = p->a + p->len++;
+	*a = tre_mem_calloc(p->mem, sizeof **a);
+	return *a;
+}
+
+static int add_icase_literals(struct literals *ls, int min, int max)
+{
+	tre_literal_t *lit;
+	int b, e, c;
+	for (c=min; c<=max; ) {
+		/* assumes islower(c) and isupper(c) are exclusive
+		   and toupper(c)!=c if islower(c).
+		   multiple opposite case characters are not supported */
+		if (tre_islower(c)) {
+			b = e = tre_toupper(c);
+			for (c++, e++; c<=max; c++, e++)
+				if (tre_toupper(c) != e) break;
+		} else if (tre_isupper(c)) {
+			b = e = tre_tolower(c);
+			for (c++, e++; c<=max; c++, e++)
+				if (tre_tolower(c) != e) break;
+		} else {
+			c++;
+			continue;
+		}
+		lit = tre_new_lit(ls);
+		if (!lit)
+			return -1;
+		lit->code_min = b;
+		lit->code_max = e-1;
+		lit->position = -1;
+	}
+	return 0;
+}
+
+
+/* Maximum number of character classes in a negated bracket expression. */
+#define MAX_NEG_CLASSES 64
+
+struct neg {
+	int negate;
+	int len;
+	tre_ctype_t a[MAX_NEG_CLASSES];
+};
+
+// TODO: parse bracket into a set of non-overlapping [lo,hi] ranges
+
+/*
+bracket grammar:
+Bracket  =  '[' List ']'  |  '[^' List ']'
+List     =  Term  |  List Term
+Term     =  Char  |  Range  |  Chclass  |  Eqclass
+Range    =  Char '-' Char  |  Char '-' '-'
+Char     =  Coll  |  coll_single
+Meta     =  ']'  |  '-'
+Coll     =  '[.' coll_single '.]'  |  '[.' coll_multi '.]'  |  '[.' Meta '.]'
+Eqclass  =  '[=' coll_single '=]'  |  '[=' coll_multi '=]'
+Chclass  =  '[:' class ':]'
+
+coll_single is a single char collating element but it can be
+ '-' only at the beginning or end of a List and
+ ']' only at the beginning of a List and
+ '^' anywhere except after the openning '['
+*/
+
+static reg_errcode_t parse_bracket_terms(tre_parse_ctx_t *ctx, const char *s, struct literals *ls, struct neg *neg)
+{
+	const char *start = s;
+	tre_ctype_t class;
+	int min, max;
+	tre_char_t wc;
+	int len;
+
+	for (;;) {
+		class = 0;
+		len = tre_mbtowc(&wc, s, 4);
+		if (len <= 0)
+			return *s ? REG_BADPAT : REG_EBRACK;
+		if (*s == ']' && s != start) {
+			ctx->s = s+1;
+			return REG_OK;
+		}
+		if (*s == '-' && s != start && s[1] != ']' &&
+		    /* extension: [a-z--@] is accepted as [a-z]|[--@] */
+		    (s[1] != '-' || s[2] == ']'))
+			return REG_ERANGE;
+		if (*s == '[' && (s[1] == '.' || s[1] == '='))
+			/* collating symbols and equivalence classes are not supported */
+			return REG_ECOLLATE;
+		if (*s == '[' && s[1] == ':') {
+			char tmp[CHARCLASS_NAME_MAX+1];
+			s += 2;
+			for (len=0; len < CHARCLASS_NAME_MAX && s[len]; len++) {
+				if (s[len] == ':') {
+					memcpy(tmp, s, len);
+					tmp[len] = 0;
+					class = tre_ctype(tmp);
+					break;
+				}
+			}
+			if (!class || s[len+1] != ']')
+				return REG_ECTYPE;
+			min = 0;
+			max = TRE_CHAR_MAX;
+			s += len+2;
+		} else {
+			min = max = wc;
+			s += len;
+			if (*s == '-' && s[1] != ']') {
+				s++;
+				len = tre_mbtowc(&wc, s, 4);
+				max = wc;
+				/* XXX - Should use collation order instead of
+				   encoding values in character ranges. */
+				if (len <= 0 || min > max)
+					return REG_ERANGE;
+				s += len;
+			}
+		}
+
+		if (class && neg->negate) {
+			if (neg->len >= MAX_NEG_CLASSES)
+				return REG_ESPACE;
+			neg->a[neg->len++] = class;
+		} else  {
+			tre_literal_t *lit = tre_new_lit(ls);
+			if (!lit)
+				return REG_ESPACE;
+			lit->code_min = min;
+			lit->code_max = max;
+			lit->class = class;
+			lit->position = -1;
+
+			/* Add opposite-case codepoints if REG_ICASE is present.
+			   It seems that POSIX requires that bracket negation
+			   should happen before case-folding, but most practical
+			   implementations do it the other way around. Changing
+			   the order would need efficient representation of
+			   case-fold ranges and bracket range sets even with
+			   simple patterns so this is ok for now. */
+			if (ctx->cflags & REG_ICASE && !class)
+				if (add_icase_literals(ls, min, max))
+					return REG_ESPACE;
+		}
+	}
+}
+
+static reg_errcode_t parse_bracket(tre_parse_ctx_t *ctx, const char *s)
+{
+	int i, max, min, negmax, negmin;
+	tre_ast_node_t *node = 0, *n;
+	tre_ctype_t *nc = 0;
+	tre_literal_t *lit;
+	struct literals ls;
+	struct neg neg;
+	reg_errcode_t err;
+
+	ls.mem = ctx->mem;
+	ls.len = 0;
+	ls.cap = 32;
+	ls.a = xmalloc(ls.cap * sizeof *ls.a);
+	if (!ls.a)
+		return REG_ESPACE;
+	neg.len = 0;
+	neg.negate = *s == '^';
+	if (neg.negate)
+		s++;
+
+	err = parse_bracket_terms(ctx, s, &ls, &neg);
+	if (err != REG_OK)
+		goto parse_bracket_done;
+
+	if (neg.negate) {
+		/*
+		 * With REG_NEWLINE, POSIX requires that newlines are not matched by
+		 * any form of a non-matching list.
+		 */
+		if (ctx->cflags & REG_NEWLINE) {
+			lit = tre_new_lit(&ls);
+			if (!lit) {
+				err = REG_ESPACE;
+				goto parse_bracket_done;
+			}
+			lit->code_min = '\n';
+			lit->code_max = '\n';
+			lit->position = -1;
+		}
+		/* Sort the array if we need to negate it. */
+		qsort(ls.a, ls.len, sizeof *ls.a, tre_compare_lit);
+		/* extra lit for the last negated range */
+		lit = tre_new_lit(&ls);
+		if (!lit) {
+			err = REG_ESPACE;
+			goto parse_bracket_done;
+		}
+		lit->code_min = TRE_CHAR_MAX+1;
+		lit->code_max = TRE_CHAR_MAX+1;
+		lit->position = -1;
+		/* negated classes */
+		if (neg.len) {
+			nc = tre_mem_alloc(ctx->mem, (neg.len+1)*sizeof *neg.a);
+			if (!nc) {
+				err = REG_ESPACE;
+				goto parse_bracket_done;
+			}
+			memcpy(nc, neg.a, neg.len*sizeof *neg.a);
+			nc[neg.len] = 0;
+		}
+	}
+
+	/* Build a union of the items in the array, negated if necessary. */
+	negmax = negmin = 0;
+	for (i = 0; i < ls.len; i++) {
+		lit = ls.a[i];
+		min = lit->code_min;
+		max = lit->code_max;
+		if (neg.negate) {
+			if (min <= negmin) {
+				/* Overlap. */
+				negmin = MAX(max + 1, negmin);
+				continue;
+			}
+			negmax = min - 1;
+			lit->code_min = negmin;
+			lit->code_max = negmax;
+			negmin = max + 1;
+		}
+		lit->position = ctx->position;
+		lit->neg_classes = nc;
+		n = tre_ast_new_node(ctx->mem, LITERAL, lit);
+		node = tre_ast_new_union(ctx->mem, node, n);
+		if (!node) {
+			err = REG_ESPACE;
+			break;
+		}
+	}
+
+parse_bracket_done:
+	xfree(ls.a);
+	ctx->position++;
+	ctx->n = node;
+	return err;
+}
+
+static const char *parse_dup_count(const char *s, int *n)
+{
+	*n = -1;
+	if (!isdigit(*s))
+		return s;
+	*n = 0;
+	for (;;) {
+		*n = 10 * *n + (*s - '0');
+		s++;
+		if (!isdigit(*s) || *n > RE_DUP_MAX)
+			break;
+	}
+	return s;
+}
+
+static const char *parse_dup(const char *s, int ere, int *pmin, int *pmax)
+{
+	int min, max;
+
+	s = parse_dup_count(s, &min);
+	if (*s == ',')
+		s = parse_dup_count(s+1, &max);
+	else
+		max = min;
+
+	if (
+		(max < min && max >= 0) ||
+		max > RE_DUP_MAX ||
+		min > RE_DUP_MAX ||
+		min < 0 ||
+		(!ere && *s++ != '\\') ||
+		*s++ != '}'
+	)
+		return 0;
+	*pmin = min;
+	*pmax = max;
+	return s;
+}
+
+static int hexval(unsigned c)
+{
+	if (c-'0'<10) return c-'0';
+	c |= 32;
+	if (c-'a'<6) return c-'a'+10;
+	return -1;
+}
+
+static reg_errcode_t marksub(tre_parse_ctx_t *ctx, tre_ast_node_t *node, int subid)
+{
+	if (node->submatch_id >= 0) {
+		tre_ast_node_t *n = tre_ast_new_literal(ctx->mem, EMPTY, -1, -1);
+		if (!n)
+			return REG_ESPACE;
+		n = tre_ast_new_catenation(ctx->mem, n, node);
+		if (!n)
+			return REG_ESPACE;
+		n->num_submatches = node->num_submatches;
+		node = n;
+	}
+	node->submatch_id = subid;
+	node->num_submatches++;
+	ctx->n = node;
+	return REG_OK;
+}
+
+/*
+BRE grammar:
+Regex  =  Branch  |  '^'  |  '$'  |  '^$'  |  '^' Branch  |  Branch '$'  |  '^' Branch '$'
+Branch =  Atom  |  Branch Atom
+Atom   =  char  |  quoted_char  |  '.'  |  Bracket  |  Atom Dup  |  '\(' Branch '\)'  |  back_ref
+Dup    =  '*'  |  '\{' Count '\}'  |  '\{' Count ',\}'  |  '\{' Count ',' Count '\}'
+
+(leading ^ and trailing $ in a sub expr may be an anchor or literal as well)
+
+ERE grammar:
+Regex  =  Branch  |  Regex '|' Branch
+Branch =  Atom  |  Branch Atom
+Atom   =  char  |  quoted_char  |  '.'  |  Bracket  |  Atom Dup  |  '(' Regex ')'  |  '^'  |  '$'
+Dup    =  '*'  |  '+'  |  '?'  |  '{' Count '}'  |  '{' Count ',}'  |  '{' Count ',' Count '}'
+
+(a*+?, ^*, $+, \X, {, (|a) are unspecified)
+*/
+
+static reg_errcode_t parse_atom(tre_parse_ctx_t *ctx, const char *s)
+{
+	int len, ere = ctx->cflags & REG_EXTENDED;
+	const char *p;
+	tre_ast_node_t *node;
+	tre_char_t wc;
+	switch (*s) {
+	case '[':
+		return parse_bracket(ctx, s+1);
+	case '\\':
+		p = tre_expand_macro(s+1);
+		if (p) {
+			/* assume \X expansion is a single atom */
+			reg_errcode_t err = parse_atom(ctx, p);
+			ctx->s = s+2;
+			return err;
+		}
+		/* extensions: \b, \B, \<, \>, \xHH \x{HHHH} */
+		switch (*++s) {
+		case 0:
+			return REG_EESCAPE;
+		case 'b':
+			node = tre_ast_new_literal(ctx->mem, ASSERTION, ASSERT_AT_WB, -1);
+			break;
+		case 'B':
+			node = tre_ast_new_literal(ctx->mem, ASSERTION, ASSERT_AT_WB_NEG, -1);
+			break;
+		case '<':
+			node = tre_ast_new_literal(ctx->mem, ASSERTION, ASSERT_AT_BOW, -1);
+			break;
+		case '>':
+			node = tre_ast_new_literal(ctx->mem, ASSERTION, ASSERT_AT_EOW, -1);
+			break;
+		case 'x':
+			s++;
+			int i, v = 0, c;
+			len = 2;
+			if (*s == '{') {
+				len = 8;
+				s++;
+			}
+			for (i=0; i<len && v<0x110000; i++) {
+				c = hexval(s[i]);
+				if (c < 0) break;
+				v = 16*v + c;
+			}
+			s += i;
+			if (len == 8) {
+				if (*s != '}')
+					return REG_EBRACE;
+				s++;
+			}
+			node = tre_ast_new_literal(ctx->mem, v, v, ctx->position++);
+			s--;
+			break;
+		case '{':
+		case '+':
+		case '?':
+			/* extension: treat \+, \? as repetitions in BRE */
+			/* reject repetitions after empty expression in BRE */
+			if (!ere)
+				return REG_BADRPT;
+		case '|':
+			/* extension: treat \| as alternation in BRE */
+			if (!ere) {
+				node = tre_ast_new_literal(ctx->mem, EMPTY, -1, -1);
+				s--;
+				goto end;
+			}
+			/* fallthrough */
+		default:
+			if (!ere && (unsigned)*s-'1' < 9) {
+				/* back reference */
+				int val = *s - '0';
+				node = tre_ast_new_literal(ctx->mem, BACKREF, val, ctx->position++);
+				ctx->max_backref = MAX(val, ctx->max_backref);
+			} else {
+				/* extension: accept unknown escaped char
+				   as a literal */
+				goto parse_literal;
+			}
+		}
+		s++;
+		break;
+	case '.':
+		if (ctx->cflags & REG_NEWLINE) {
+			tre_ast_node_t *tmp1, *tmp2;
+			tmp1 = tre_ast_new_literal(ctx->mem, 0, '\n'-1, ctx->position++);
+			tmp2 = tre_ast_new_literal(ctx->mem, '\n'+1, TRE_CHAR_MAX, ctx->position++);
+			if (tmp1 && tmp2)
+				node = tre_ast_new_union(ctx->mem, tmp1, tmp2);
+			else
+				node = 0;
+		} else {
+			node = tre_ast_new_literal(ctx->mem, 0, TRE_CHAR_MAX, ctx->position++);
+		}
+		s++;
+		break;
+	case '^':
+		/* '^' has a special meaning everywhere in EREs, and at beginning of BRE. */
+		if (!ere && s != ctx->start)
+			goto parse_literal;
+		node = tre_ast_new_literal(ctx->mem, ASSERTION, ASSERT_AT_BOL, -1);
+		s++;
+		break;
+	case '$':
+		/* '$' is special everywhere in EREs, and at the end of a BRE subexpression. */
+		if (!ere && s[1] && (s[1]!='\\'|| (s[2]!=')' && s[2]!='|')))
+			goto parse_literal;
+		node = tre_ast_new_literal(ctx->mem, ASSERTION, ASSERT_AT_EOL, -1);
+		s++;
+		break;
+	case '*':
+	case '{':
+	case '+':
+	case '?':
+		/* reject repetitions after empty expression in ERE */
+		if (ere)
+			return REG_BADRPT;
+	case '|':
+		if (!ere)
+			goto parse_literal;
+	case 0:
+		node = tre_ast_new_literal(ctx->mem, EMPTY, -1, -1);
+		break;
+	default:
+parse_literal:
+		len = tre_mbtowc(&wc, s, 4);
+		if (len < 0)
+			return REG_BADPAT;
+		if (ctx->cflags & REG_ICASE && (tre_isupper(wc) || tre_islower(wc))) {
+			tre_ast_node_t *tmp1, *tmp2;
+			/* multiple opposite case characters are not supported */
+			tmp1 = tre_ast_new_literal(ctx->mem, tre_toupper(wc), tre_toupper(wc), ctx->position);
+			tmp2 = tre_ast_new_literal(ctx->mem, tre_tolower(wc), tre_tolower(wc), ctx->position);
+			if (tmp1 && tmp2)
+				node = tre_ast_new_union(ctx->mem, tmp1, tmp2);
+			else
+				node = 0;
+		} else {
+			node = tre_ast_new_literal(ctx->mem, wc, wc, ctx->position);
+		}
+		ctx->position++;
+		s += len;
+		break;
+	}
+end:
+	if (!node)
+		return REG_ESPACE;
+	ctx->n = node;
+	ctx->s = s;
+	return REG_OK;
+}
+
+#define PUSHPTR(err, s, v) do { \
+	if ((err = tre_stack_push_voidptr(s, v)) != REG_OK) \
+		return err; \
+} while(0)
+
+#define PUSHINT(err, s, v) do { \
+	if ((err = tre_stack_push_int(s, v)) != REG_OK) \
+		return err; \
+} while(0)
+
+static reg_errcode_t tre_parse(tre_parse_ctx_t *ctx)
+{
+	tre_ast_node_t *nbranch=0, *nunion=0;
+	int ere = ctx->cflags & REG_EXTENDED;
+	const char *s = ctx->start;
+	int subid = 0;
+	int depth = 0;
+	reg_errcode_t err;
+	tre_stack_t *stack = ctx->stack;
+
+	PUSHINT(err, stack, subid++);
+	for (;;) {
+		if ((!ere && *s == '\\' && s[1] == '(') ||
+		    (ere && *s == '(')) {
+			PUSHPTR(err, stack, nunion);
+			PUSHPTR(err, stack, nbranch);
+			PUSHINT(err, stack, subid++);
+			s++;
+			if (!ere)
+				s++;
+			depth++;
+			nbranch = nunion = 0;
+			ctx->start = s;
+			continue;
+		}
+		if ((!ere && *s == '\\' && s[1] == ')') ||
+		    (ere && *s == ')' && depth)) {
+			ctx->n = tre_ast_new_literal(ctx->mem, EMPTY, -1, -1);
+			if (!ctx->n)
+				return REG_ESPACE;
+		} else {
+			err = parse_atom(ctx, s);
+			if (err != REG_OK)
+				return err;
+			s = ctx->s;
+		}
+
+	parse_iter:
+		for (;;) {
+			int min, max;
+
+			if (*s!='\\' && *s!='*') {
+				if (!ere)
+					break;
+				if (*s!='+' && *s!='?' && *s!='{')
+					break;
+			}
+			if (*s=='\\' && ere)
+				break;
+			/* extension: treat \+, \? as repetitions in BRE */
+			if (*s=='\\' && s[1]!='+' && s[1]!='?' && s[1]!='{')
+				break;
+			if (*s=='\\')
+				s++;
+
+			/* handle ^* at the start of a BRE. */
+			if (!ere && s==ctx->start+1 && s[-1]=='^')
+				break;
+
+			/* extension: multiple consecutive *+?{,} is unspecified,
+			   but (a+)+ has to be supported so accepting a++ makes
+			   sense, note however that the RE_DUP_MAX limit can be
+			   circumvented: (a{255}){255} uses a lot of memory.. */
+			if (*s=='{') {
+				s = parse_dup(s+1, ere, &min, &max);
+				if (!s)
+					return REG_BADBR;
+			} else {
+				min=0;
+				max=-1;
+				if (*s == '+')
+					min = 1;
+				if (*s == '?')
+					max = 1;
+				s++;
+			}
+			if (max == 0)
+				ctx->n = tre_ast_new_literal(ctx->mem, EMPTY, -1, -1);
+			else
+				ctx->n = tre_ast_new_iter(ctx->mem, ctx->n, min, max, 0);
+			if (!ctx->n)
+				return REG_ESPACE;
+		}
+
+		nbranch = tre_ast_new_catenation(ctx->mem, nbranch, ctx->n);
+		if ((ere && *s == '|') ||
+		    (ere && *s == ')' && depth) ||
+		    (!ere && *s == '\\' && s[1] == ')') ||
+		    /* extension: treat \| as alternation in BRE */
+		    (!ere && *s == '\\' && s[1] == '|') ||
+		    !*s) {
+			/* extension: empty branch is unspecified (), (|a), (a|)
+			   here they are not rejected but match on empty string */
+			int c = *s;
+			nunion = tre_ast_new_union(ctx->mem, nunion, nbranch);
+			nbranch = 0;
+
+			if (c == '\\' && s[1] == '|') {
+				s+=2;
+				ctx->start = s;
+			} else if (c == '|') {
+				s++;
+				ctx->start = s;
+			} else {
+				if (c == '\\') {
+					if (!depth) return REG_EPAREN;
+					s+=2;
+				} else if (c == ')')
+					s++;
+				depth--;
+				err = marksub(ctx, nunion, tre_stack_pop_int(stack));
+				if (err != REG_OK)
+					return err;
+				if (!c && depth<0) {
+					ctx->submatch_id = subid;
+					return REG_OK;
+				}
+				if (!c || depth<0)
+					return REG_EPAREN;
+				nbranch = tre_stack_pop_voidptr(stack);
+				nunion = tre_stack_pop_voidptr(stack);
+				goto parse_iter;
+			}
+		}
+	}
+}
+
+
+/***********************************************************************
+ from tre-compile.c
+***********************************************************************/
+
+
+/*
+  TODO:
+   - Fix tre_ast_to_tnfa() to recurse using a stack instead of recursive
+     function calls.
+*/
+
+/*
+  Algorithms to setup tags so that submatch addressing can be done.
+*/
+
+
+/* Inserts a catenation node to the root of the tree given in `node'.
+   As the left child a new tag with number `tag_id' to `node' is added,
+   and the right child is the old root. */
+static reg_errcode_t
+tre_add_tag_left(tre_mem_t mem, tre_ast_node_t *node, int tag_id)
+{
+  tre_catenation_t *c;
+
+  c = tre_mem_alloc(mem, sizeof(*c));
+  if (c == NULL)
+    return REG_ESPACE;
+  c->left = tre_ast_new_literal(mem, TAG, tag_id, -1);
+  if (c->left == NULL)
+    return REG_ESPACE;
+  c->right = tre_mem_alloc(mem, sizeof(tre_ast_node_t));
+  if (c->right == NULL)
+    return REG_ESPACE;
+
+  c->right->obj = node->obj;
+  c->right->type = node->type;
+  c->right->nullable = -1;
+  c->right->submatch_id = -1;
+  c->right->firstpos = NULL;
+  c->right->lastpos = NULL;
+  c->right->num_tags = 0;
+  c->right->num_submatches = 0;
+  node->obj = c;
+  node->type = CATENATION;
+  return REG_OK;
+}
+
+/* Inserts a catenation node to the root of the tree given in `node'.
+   As the right child a new tag with number `tag_id' to `node' is added,
+   and the left child is the old root. */
+static reg_errcode_t
+tre_add_tag_right(tre_mem_t mem, tre_ast_node_t *node, int tag_id)
+{
+  tre_catenation_t *c;
+
+  c = tre_mem_alloc(mem, sizeof(*c));
+  if (c == NULL)
+    return REG_ESPACE;
+  c->right = tre_ast_new_literal(mem, TAG, tag_id, -1);
+  if (c->right == NULL)
+    return REG_ESPACE;
+  c->left = tre_mem_alloc(mem, sizeof(tre_ast_node_t));
+  if (c->left == NULL)
+    return REG_ESPACE;
+
+  c->left->obj = node->obj;
+  c->left->type = node->type;
+  c->left->nullable = -1;
+  c->left->submatch_id = -1;
+  c->left->firstpos = NULL;
+  c->left->lastpos = NULL;
+  c->left->num_tags = 0;
+  c->left->num_submatches = 0;
+  node->obj = c;
+  node->type = CATENATION;
+  return REG_OK;
+}
+
+typedef enum {
+  ADDTAGS_RECURSE,
+  ADDTAGS_AFTER_ITERATION,
+  ADDTAGS_AFTER_UNION_LEFT,
+  ADDTAGS_AFTER_UNION_RIGHT,
+  ADDTAGS_AFTER_CAT_LEFT,
+  ADDTAGS_AFTER_CAT_RIGHT,
+  ADDTAGS_SET_SUBMATCH_END
+} tre_addtags_symbol_t;
+
+
+typedef struct {
+  int tag;
+  int next_tag;
+} tre_tag_states_t;
+
+
+/* Go through `regset' and set submatch data for submatches that are
+   using this tag. */
+static void
+tre_purge_regset(int *regset, tre_tnfa_t *tnfa, int tag)
+{
+  int i;
+
+  for (i = 0; regset[i] >= 0; i++)
+    {
+      int id = regset[i] / 2;
+      int start = !(regset[i] % 2);
+      if (start)
+	tnfa->submatch_data[id].so_tag = tag;
+      else
+	tnfa->submatch_data[id].eo_tag = tag;
+    }
+  regset[0] = -1;
+}
+
+
+/* Adds tags to appropriate locations in the parse tree in `tree', so that
+   subexpressions marked for submatch addressing can be traced. */
+static reg_errcode_t
+tre_add_tags(tre_mem_t mem, tre_stack_t *stack, tre_ast_node_t *tree,
+	     tre_tnfa_t *tnfa)
+{
+  reg_errcode_t status = REG_OK;
+  tre_addtags_symbol_t symbol;
+  tre_ast_node_t *node = tree; /* Tree node we are currently looking at. */
+  int bottom = tre_stack_num_objects(stack);
+  /* True for first pass (counting number of needed tags) */
+  int first_pass = (mem == NULL || tnfa == NULL);
+  int *regset, *orig_regset;
+  int num_tags = 0; /* Total number of tags. */
+  int num_minimals = 0;	 /* Number of special minimal tags. */
+  int tag = 0;	    /* The tag that is to be added next. */
+  int next_tag = 1; /* Next tag to use after this one. */
+  int *parents;	    /* Stack of submatches the current submatch is
+		       contained in. */
+  int minimal_tag = -1; /* Tag that marks the beginning of a minimal match. */
+  tre_tag_states_t *saved_states;
+
+  tre_tag_direction_t direction = TRE_TAG_MINIMIZE;
+  if (!first_pass)
+    {
+      tnfa->end_tag = 0;
+      tnfa->minimal_tags[0] = -1;
+    }
+
+  regset = xmalloc(sizeof(*regset) * ((tnfa->num_submatches + 1) * 2));
+  if (regset == NULL)
+    return REG_ESPACE;
+  regset[0] = -1;
+  orig_regset = regset;
+
+  parents = xmalloc(sizeof(*parents) * (tnfa->num_submatches + 1));
+  if (parents == NULL)
+    {
+      xfree(regset);
+      return REG_ESPACE;
+    }
+  parents[0] = -1;
+
+  saved_states = xmalloc(sizeof(*saved_states) * (tnfa->num_submatches + 1));
+  if (saved_states == NULL)
+    {
+      xfree(regset);
+      xfree(parents);
+      return REG_ESPACE;
+    }
+  else
+    {
+      unsigned int i;
+      for (i = 0; i <= tnfa->num_submatches; i++)
+	saved_states[i].tag = -1;
+    }
+
+  STACK_PUSH(stack, voidptr, node);
+  STACK_PUSH(stack, int, ADDTAGS_RECURSE);
+
+  while (tre_stack_num_objects(stack) > bottom)
+    {
+      if (status != REG_OK)
+	break;
+
+      symbol = (tre_addtags_symbol_t)tre_stack_pop_int(stack);
+      switch (symbol)
+	{
+
+	case ADDTAGS_SET_SUBMATCH_END:
+	  {
+	    int id = tre_stack_pop_int(stack);
+	    int i;
+
+	    /* Add end of this submatch to regset. */
+	    for (i = 0; regset[i] >= 0; i++);
+	    regset[i] = id * 2 + 1;
+	    regset[i + 1] = -1;
+
+	    /* Pop this submatch from the parents stack. */
+	    for (i = 0; parents[i] >= 0; i++);
+	    parents[i - 1] = -1;
+	    break;
+	  }
+
+	case ADDTAGS_RECURSE:
+	  node = tre_stack_pop_voidptr(stack);
+
+	  if (node->submatch_id >= 0)
+	    {
+	      int id = node->submatch_id;
+	      int i;
+
+
+	      /* Add start of this submatch to regset. */
+	      for (i = 0; regset[i] >= 0; i++);
+	      regset[i] = id * 2;
+	      regset[i + 1] = -1;
+
+	      if (!first_pass)
+		{
+		  for (i = 0; parents[i] >= 0; i++);
+		  tnfa->submatch_data[id].parents = NULL;
+		  if (i > 0)
+		    {
+		      int *p = xmalloc(sizeof(*p) * (i + 1));
+		      if (p == NULL)
+			{
+			  status = REG_ESPACE;
+			  break;
+			}
+		      assert(tnfa->submatch_data[id].parents == NULL);
+		      tnfa->submatch_data[id].parents = p;
+		      for (i = 0; parents[i] >= 0; i++)
+			p[i] = parents[i];
+		      p[i] = -1;
+		    }
+		}
+
+	      /* Add end of this submatch to regset after processing this
+		 node. */
+	      STACK_PUSHX(stack, int, node->submatch_id);
+	      STACK_PUSHX(stack, int, ADDTAGS_SET_SUBMATCH_END);
+	    }
+
+	  switch (node->type)
+	    {
+	    case LITERAL:
+	      {
+		tre_literal_t *lit = node->obj;
+
+		if (!IS_SPECIAL(lit) || IS_BACKREF(lit))
+		  {
+		    int i;
+		    if (regset[0] >= 0)
+		      {
+			/* Regset is not empty, so add a tag before the
+			   literal or backref. */
+			if (!first_pass)
+			  {
+			    status = tre_add_tag_left(mem, node, tag);
+			    tnfa->tag_directions[tag] = direction;
+			    if (minimal_tag >= 0)
+			      {
+				for (i = 0; tnfa->minimal_tags[i] >= 0; i++);
+				tnfa->minimal_tags[i] = tag;
+				tnfa->minimal_tags[i + 1] = minimal_tag;
+				tnfa->minimal_tags[i + 2] = -1;
+				minimal_tag = -1;
+				num_minimals++;
+			      }
+			    tre_purge_regset(regset, tnfa, tag);
+			  }
+			else
+			  {
+			    node->num_tags = 1;
+			  }
+
+			regset[0] = -1;
+			tag = next_tag;
+			num_tags++;
+			next_tag++;
+		      }
+		  }
+		else
+		  {
+		    assert(!IS_TAG(lit));
+		  }
+		break;
+	      }
+	    case CATENATION:
+	      {
+		tre_catenation_t *cat = node->obj;
+		tre_ast_node_t *left = cat->left;
+		tre_ast_node_t *right = cat->right;
+		int reserved_tag = -1;
+
+
+		/* After processing right child. */
+		STACK_PUSHX(stack, voidptr, node);
+		STACK_PUSHX(stack, int, ADDTAGS_AFTER_CAT_RIGHT);
+
+		/* Process right child. */
+		STACK_PUSHX(stack, voidptr, right);
+		STACK_PUSHX(stack, int, ADDTAGS_RECURSE);
+
+		/* After processing left child. */
+		STACK_PUSHX(stack, int, next_tag + left->num_tags);
+		if (left->num_tags > 0 && right->num_tags > 0)
+		  {
+		    /* Reserve the next tag to the right child. */
+		    reserved_tag = next_tag;
+		    next_tag++;
+		  }
+		STACK_PUSHX(stack, int, reserved_tag);
+		STACK_PUSHX(stack, int, ADDTAGS_AFTER_CAT_LEFT);
+
+		/* Process left child. */
+		STACK_PUSHX(stack, voidptr, left);
+		STACK_PUSHX(stack, int, ADDTAGS_RECURSE);
+
+		}
+	      break;
+	    case ITERATION:
+	      {
+		tre_iteration_t *iter = node->obj;
+
+		if (first_pass)
+		  {
+		    STACK_PUSHX(stack, int, regset[0] >= 0 || iter->minimal);
+		  }
+		else
+		  {
+		    STACK_PUSHX(stack, int, tag);
+		    STACK_PUSHX(stack, int, iter->minimal);
+		  }
+		STACK_PUSHX(stack, voidptr, node);
+		STACK_PUSHX(stack, int, ADDTAGS_AFTER_ITERATION);
+
+		STACK_PUSHX(stack, voidptr, iter->arg);
+		STACK_PUSHX(stack, int, ADDTAGS_RECURSE);
+
+		/* Regset is not empty, so add a tag here. */
+		if (regset[0] >= 0 || iter->minimal)
+		  {
+		    if (!first_pass)
+		      {
+			int i;
+			status = tre_add_tag_left(mem, node, tag);
+			if (iter->minimal)
+			  tnfa->tag_directions[tag] = TRE_TAG_MAXIMIZE;
+			else
+			  tnfa->tag_directions[tag] = direction;
+			if (minimal_tag >= 0)
+			  {
+			    for (i = 0; tnfa->minimal_tags[i] >= 0; i++);
+			    tnfa->minimal_tags[i] = tag;
+			    tnfa->minimal_tags[i + 1] = minimal_tag;
+			    tnfa->minimal_tags[i + 2] = -1;
+			    minimal_tag = -1;
+			    num_minimals++;
+			  }
+			tre_purge_regset(regset, tnfa, tag);
+		      }
+
+		    regset[0] = -1;
+		    tag = next_tag;
+		    num_tags++;
+		    next_tag++;
+		  }
+		direction = TRE_TAG_MINIMIZE;
+	      }
+	      break;
+	    case UNION:
+	      {
+		tre_union_t *uni = node->obj;
+		tre_ast_node_t *left = uni->left;
+		tre_ast_node_t *right = uni->right;
+		int left_tag;
+		int right_tag;
+
+		if (regset[0] >= 0)
+		  {
+		    left_tag = next_tag;
+		    right_tag = next_tag + 1;
+		  }
+		else
+		  {
+		    left_tag = tag;
+		    right_tag = next_tag;
+		  }
+
+		/* After processing right child. */
+		STACK_PUSHX(stack, int, right_tag);
+		STACK_PUSHX(stack, int, left_tag);
+		STACK_PUSHX(stack, voidptr, regset);
+		STACK_PUSHX(stack, int, regset[0] >= 0);
+		STACK_PUSHX(stack, voidptr, node);
+		STACK_PUSHX(stack, voidptr, right);
+		STACK_PUSHX(stack, voidptr, left);
+		STACK_PUSHX(stack, int, ADDTAGS_AFTER_UNION_RIGHT);
+
+		/* Process right child. */
+		STACK_PUSHX(stack, voidptr, right);
+		STACK_PUSHX(stack, int, ADDTAGS_RECURSE);
+
+		/* After processing left child. */
+		STACK_PUSHX(stack, int, ADDTAGS_AFTER_UNION_LEFT);
+
+		/* Process left child. */
+		STACK_PUSHX(stack, voidptr, left);
+		STACK_PUSHX(stack, int, ADDTAGS_RECURSE);
+
+		/* Regset is not empty, so add a tag here. */
+		if (regset[0] >= 0)
+		  {
+		    if (!first_pass)
+		      {
+			int i;
+			status = tre_add_tag_left(mem, node, tag);
+			tnfa->tag_directions[tag] = direction;
+			if (minimal_tag >= 0)
+			  {
+			    for (i = 0; tnfa->minimal_tags[i] >= 0; i++);
+			    tnfa->minimal_tags[i] = tag;
+			    tnfa->minimal_tags[i + 1] = minimal_tag;
+			    tnfa->minimal_tags[i + 2] = -1;
+			    minimal_tag = -1;
+			    num_minimals++;
+			  }
+			tre_purge_regset(regset, tnfa, tag);
+		      }
+
+		    regset[0] = -1;
+		    tag = next_tag;
+		    num_tags++;
+		    next_tag++;
+		  }
+
+		if (node->num_submatches > 0)
+		  {
+		    /* The next two tags are reserved for markers. */
+		    next_tag++;
+		    tag = next_tag;
+		    next_tag++;
+		  }
+
+		break;
+	      }
+	    }
+
+	  if (node->submatch_id >= 0)
+	    {
+	      int i;
+	      /* Push this submatch on the parents stack. */
+	      for (i = 0; parents[i] >= 0; i++);
+	      parents[i] = node->submatch_id;
+	      parents[i + 1] = -1;
+	    }
+
+	  break; /* end case: ADDTAGS_RECURSE */
+
+	case ADDTAGS_AFTER_ITERATION:
+	  {
+	    int minimal = 0;
+	    int enter_tag;
+	    node = tre_stack_pop_voidptr(stack);
+	    if (first_pass)
+	      {
+		node->num_tags = ((tre_iteration_t *)node->obj)->arg->num_tags
+		  + tre_stack_pop_int(stack);
+		minimal_tag = -1;
+	      }
+	    else
+	      {
+		minimal = tre_stack_pop_int(stack);
+		enter_tag = tre_stack_pop_int(stack);
+		if (minimal)
+		  minimal_tag = enter_tag;
+	      }
+
+	    if (!first_pass)
+	      {
+		if (minimal)
+		  direction = TRE_TAG_MINIMIZE;
+		else
+		  direction = TRE_TAG_MAXIMIZE;
+	      }
+	    break;
+	  }
+
+	case ADDTAGS_AFTER_CAT_LEFT:
+	  {
+	    int new_tag = tre_stack_pop_int(stack);
+	    next_tag = tre_stack_pop_int(stack);
+	    if (new_tag >= 0)
+	      {
+		tag = new_tag;
+	      }
+	    break;
+	  }
+
+	case ADDTAGS_AFTER_CAT_RIGHT:
+	  node = tre_stack_pop_voidptr(stack);
+	  if (first_pass)
+	    node->num_tags = ((tre_catenation_t *)node->obj)->left->num_tags
+	      + ((tre_catenation_t *)node->obj)->right->num_tags;
+	  break;
+
+	case ADDTAGS_AFTER_UNION_LEFT:
+	  /* Lift the bottom of the `regset' array so that when processing
+	     the right operand the items currently in the array are
+	     invisible.	 The original bottom was saved at ADDTAGS_UNION and
+	     will be restored at ADDTAGS_AFTER_UNION_RIGHT below. */
+	  while (*regset >= 0)
+	    regset++;
+	  break;
+
+	case ADDTAGS_AFTER_UNION_RIGHT:
+	  {
+	    int added_tags, tag_left, tag_right;
+	    tre_ast_node_t *left = tre_stack_pop_voidptr(stack);
+	    tre_ast_node_t *right = tre_stack_pop_voidptr(stack);
+	    node = tre_stack_pop_voidptr(stack);
+	    added_tags = tre_stack_pop_int(stack);
+	    if (first_pass)
+	      {
+		node->num_tags = ((tre_union_t *)node->obj)->left->num_tags
+		  + ((tre_union_t *)node->obj)->right->num_tags + added_tags
+		  + ((node->num_submatches > 0) ? 2 : 0);
+	      }
+	    regset = tre_stack_pop_voidptr(stack);
+	    tag_left = tre_stack_pop_int(stack);
+	    tag_right = tre_stack_pop_int(stack);
+
+	    /* Add tags after both children, the left child gets a smaller
+	       tag than the right child.  This guarantees that we prefer
+	       the left child over the right child. */
+	    /* XXX - This is not always necessary (if the children have
+	       tags which must be seen for every match of that child). */
+	    /* XXX - Check if this is the only place where tre_add_tag_right
+	       is used.	 If so, use tre_add_tag_left (putting the tag before
+	       the child as opposed after the child) and throw away
+	       tre_add_tag_right. */
+	    if (node->num_submatches > 0)
+	      {
+		if (!first_pass)
+		  {
+		    status = tre_add_tag_right(mem, left, tag_left);
+		    tnfa->tag_directions[tag_left] = TRE_TAG_MAXIMIZE;
+		    if (status == REG_OK)
+		      status = tre_add_tag_right(mem, right, tag_right);
+		    tnfa->tag_directions[tag_right] = TRE_TAG_MAXIMIZE;
+		  }
+		num_tags += 2;
+	      }
+	    direction = TRE_TAG_MAXIMIZE;
+	    break;
+	  }
+
+	default:
+	  assert(0);
+	  break;
+
+	} /* end switch(symbol) */
+    } /* end while(tre_stack_num_objects(stack) > bottom) */
+
+  if (!first_pass)
+    tre_purge_regset(regset, tnfa, tag);
+
+  if (!first_pass && minimal_tag >= 0)
+    {
+      int i;
+      for (i = 0; tnfa->minimal_tags[i] >= 0; i++);
+      tnfa->minimal_tags[i] = tag;
+      tnfa->minimal_tags[i + 1] = minimal_tag;
+      tnfa->minimal_tags[i + 2] = -1;
+      minimal_tag = -1;
+      num_minimals++;
+    }
+
+  assert(tree->num_tags == num_tags);
+  tnfa->end_tag = num_tags;
+  tnfa->num_tags = num_tags;
+  tnfa->num_minimals = num_minimals;
+  xfree(orig_regset);
+  xfree(parents);
+  xfree(saved_states);
+  return status;
+}
+
+
+
+/*
+  AST to TNFA compilation routines.
+*/
+
+typedef enum {
+  COPY_RECURSE,
+  COPY_SET_RESULT_PTR
+} tre_copyast_symbol_t;
+
+/* Flags for tre_copy_ast(). */
+#define COPY_REMOVE_TAGS	 1
+#define COPY_MAXIMIZE_FIRST_TAG	 2
+
+static reg_errcode_t
+tre_copy_ast(tre_mem_t mem, tre_stack_t *stack, tre_ast_node_t *ast,
+	     int flags, int *pos_add, tre_tag_direction_t *tag_directions,
+	     tre_ast_node_t **copy, int *max_pos)
+{
+  reg_errcode_t status = REG_OK;
+  int bottom = tre_stack_num_objects(stack);
+  int num_copied = 0;
+  int first_tag = 1;
+  tre_ast_node_t **result = copy;
+  tre_copyast_symbol_t symbol;
+
+  STACK_PUSH(stack, voidptr, ast);
+  STACK_PUSH(stack, int, COPY_RECURSE);
+
+  while (status == REG_OK && tre_stack_num_objects(stack) > bottom)
+    {
+      tre_ast_node_t *node;
+      if (status != REG_OK)
+	break;
+
+      symbol = (tre_copyast_symbol_t)tre_stack_pop_int(stack);
+      switch (symbol)
+	{
+	case COPY_SET_RESULT_PTR:
+	  result = tre_stack_pop_voidptr(stack);
+	  break;
+	case COPY_RECURSE:
+	  node = tre_stack_pop_voidptr(stack);
+	  switch (node->type)
+	    {
+	    case LITERAL:
+	      {
+		tre_literal_t *lit = node->obj;
+		int pos = lit->position;
+		int min = lit->code_min;
+		int max = lit->code_max;
+		if (!IS_SPECIAL(lit) || IS_BACKREF(lit))
+		  {
+		    /* XXX - e.g. [ab] has only one position but two
+		       nodes, so we are creating holes in the state space
+		       here.  Not fatal, just wastes memory. */
+		    pos += *pos_add;
+		    num_copied++;
+		  }
+		else if (IS_TAG(lit) && (flags & COPY_REMOVE_TAGS))
+		  {
+		    /* Change this tag to empty. */
+		    min = EMPTY;
+		    max = pos = -1;
+		  }
+		else if (IS_TAG(lit) && (flags & COPY_MAXIMIZE_FIRST_TAG)
+			 && first_tag)
+		  {
+		    /* Maximize the first tag. */
+		    tag_directions[max] = TRE_TAG_MAXIMIZE;
+		    first_tag = 0;
+		  }
+		*result = tre_ast_new_literal(mem, min, max, pos);
+		if (*result == NULL)
+		  status = REG_ESPACE;
+		else {
+		  tre_literal_t *p = (*result)->obj;
+		  p->class = lit->class;
+		  p->neg_classes = lit->neg_classes;
+		}
+
+		if (pos > *max_pos)
+		  *max_pos = pos;
+		break;
+	      }
+	    case UNION:
+	      {
+		tre_union_t *uni = node->obj;
+		tre_union_t *tmp;
+		*result = tre_ast_new_union(mem, uni->left, uni->right);
+		if (*result == NULL)
+		  {
+		    status = REG_ESPACE;
+		    break;
+		  }
+		tmp = (*result)->obj;
+		result = &tmp->left;
+		STACK_PUSHX(stack, voidptr, uni->right);
+		STACK_PUSHX(stack, int, COPY_RECURSE);
+		STACK_PUSHX(stack, voidptr, &tmp->right);
+		STACK_PUSHX(stack, int, COPY_SET_RESULT_PTR);
+		STACK_PUSHX(stack, voidptr, uni->left);
+		STACK_PUSHX(stack, int, COPY_RECURSE);
+		break;
+	      }
+	    case CATENATION:
+	      {
+		tre_catenation_t *cat = node->obj;
+		tre_catenation_t *tmp;
+		*result = tre_ast_new_catenation(mem, cat->left, cat->right);
+		if (*result == NULL)
+		  {
+		    status = REG_ESPACE;
+		    break;
+		  }
+		tmp = (*result)->obj;
+		tmp->left = NULL;
+		tmp->right = NULL;
+		result = &tmp->left;
+
+		STACK_PUSHX(stack, voidptr, cat->right);
+		STACK_PUSHX(stack, int, COPY_RECURSE);
+		STACK_PUSHX(stack, voidptr, &tmp->right);
+		STACK_PUSHX(stack, int, COPY_SET_RESULT_PTR);
+		STACK_PUSHX(stack, voidptr, cat->left);
+		STACK_PUSHX(stack, int, COPY_RECURSE);
+		break;
+	      }
+	    case ITERATION:
+	      {
+		tre_iteration_t *iter = node->obj;
+		STACK_PUSHX(stack, voidptr, iter->arg);
+		STACK_PUSHX(stack, int, COPY_RECURSE);
+		*result = tre_ast_new_iter(mem, iter->arg, iter->min,
+					   iter->max, iter->minimal);
+		if (*result == NULL)
+		  {
+		    status = REG_ESPACE;
+		    break;
+		  }
+		iter = (*result)->obj;
+		result = &iter->arg;
+		break;
+	      }
+	    default:
+	      assert(0);
+	      break;
+	    }
+	  break;
+	}
+    }
+  *pos_add += num_copied;
+  return status;
+}
+
+typedef enum {
+  EXPAND_RECURSE,
+  EXPAND_AFTER_ITER
+} tre_expand_ast_symbol_t;
+
+/* Expands each iteration node that has a finite nonzero minimum or maximum
+   iteration count to a catenated sequence of copies of the node. */
+static reg_errcode_t
+tre_expand_ast(tre_mem_t mem, tre_stack_t *stack, tre_ast_node_t *ast,
+	       int *position, tre_tag_direction_t *tag_directions)
+{
+  reg_errcode_t status = REG_OK;
+  int bottom = tre_stack_num_objects(stack);
+  int pos_add = 0;
+  int pos_add_total = 0;
+  int max_pos = 0;
+  int iter_depth = 0;
+
+  STACK_PUSHR(stack, voidptr, ast);
+  STACK_PUSHR(stack, int, EXPAND_RECURSE);
+  while (status == REG_OK && tre_stack_num_objects(stack) > bottom)
+    {
+      tre_ast_node_t *node;
+      tre_expand_ast_symbol_t symbol;
+
+      if (status != REG_OK)
+	break;
+
+      symbol = (tre_expand_ast_symbol_t)tre_stack_pop_int(stack);
+      node = tre_stack_pop_voidptr(stack);
+      switch (symbol)
+	{
+	case EXPAND_RECURSE:
+	  switch (node->type)
+	    {
+	    case LITERAL:
+	      {
+		tre_literal_t *lit= node->obj;
+		if (!IS_SPECIAL(lit) || IS_BACKREF(lit))
+		  {
+		    lit->position += pos_add;
+		    if (lit->position > max_pos)
+		      max_pos = lit->position;
+		  }
+		break;
+	      }
+	    case UNION:
+	      {
+		tre_union_t *uni = node->obj;
+		STACK_PUSHX(stack, voidptr, uni->right);
+		STACK_PUSHX(stack, int, EXPAND_RECURSE);
+		STACK_PUSHX(stack, voidptr, uni->left);
+		STACK_PUSHX(stack, int, EXPAND_RECURSE);
+		break;
+	      }
+	    case CATENATION:
+	      {
+		tre_catenation_t *cat = node->obj;
+		STACK_PUSHX(stack, voidptr, cat->right);
+		STACK_PUSHX(stack, int, EXPAND_RECURSE);
+		STACK_PUSHX(stack, voidptr, cat->left);
+		STACK_PUSHX(stack, int, EXPAND_RECURSE);
+		break;
+	      }
+	    case ITERATION:
+	      {
+		tre_iteration_t *iter = node->obj;
+		STACK_PUSHX(stack, int, pos_add);
+		STACK_PUSHX(stack, voidptr, node);
+		STACK_PUSHX(stack, int, EXPAND_AFTER_ITER);
+		STACK_PUSHX(stack, voidptr, iter->arg);
+		STACK_PUSHX(stack, int, EXPAND_RECURSE);
+		/* If we are going to expand this node at EXPAND_AFTER_ITER
+		   then don't increase the `pos' fields of the nodes now, it
+		   will get done when expanding. */
+		if (iter->min > 1 || iter->max > 1)
+		  pos_add = 0;
+		iter_depth++;
+		break;
+	      }
+	    default:
+	      assert(0);
+	      break;
+	    }
+	  break;
+	case EXPAND_AFTER_ITER:
+	  {
+	    tre_iteration_t *iter = node->obj;
+	    int pos_add_last;
+	    pos_add = tre_stack_pop_int(stack);
+	    pos_add_last = pos_add;
+	    if (iter->min > 1 || iter->max > 1)
+	      {
+		tre_ast_node_t *seq1 = NULL, *seq2 = NULL;
+		int j;
+		int pos_add_save = pos_add;
+
+		/* Create a catenated sequence of copies of the node. */
+		for (j = 0; j < iter->min; j++)
+		  {
+		    tre_ast_node_t *copy;
+		    /* Remove tags from all but the last copy. */
+		    int flags = ((j + 1 < iter->min)
+				 ? COPY_REMOVE_TAGS
+				 : COPY_MAXIMIZE_FIRST_TAG);
+		    pos_add_save = pos_add;
+		    status = tre_copy_ast(mem, stack, iter->arg, flags,
+					  &pos_add, tag_directions, &copy,
+					  &max_pos);
+		    if (status != REG_OK)
+		      return status;
+		    if (seq1 != NULL)
+		      seq1 = tre_ast_new_catenation(mem, seq1, copy);
+		    else
+		      seq1 = copy;
+		    if (seq1 == NULL)
+		      return REG_ESPACE;
+		  }
+
+		if (iter->max == -1)
+		  {
+		    /* No upper limit. */
+		    pos_add_save = pos_add;
+		    status = tre_copy_ast(mem, stack, iter->arg, 0,
+					  &pos_add, NULL, &seq2, &max_pos);
+		    if (status != REG_OK)
+		      return status;
+		    seq2 = tre_ast_new_iter(mem, seq2, 0, -1, 0);
+		    if (seq2 == NULL)
+		      return REG_ESPACE;
+		  }
+		else
+		  {
+		    for (j = iter->min; j < iter->max; j++)
+		      {
+			tre_ast_node_t *tmp, *copy;
+			pos_add_save = pos_add;
+			status = tre_copy_ast(mem, stack, iter->arg, 0,
+					      &pos_add, NULL, &copy, &max_pos);
+			if (status != REG_OK)
+			  return status;
+			if (seq2 != NULL)
+			  seq2 = tre_ast_new_catenation(mem, copy, seq2);
+			else
+			  seq2 = copy;
+			if (seq2 == NULL)
+			  return REG_ESPACE;
+			tmp = tre_ast_new_literal(mem, EMPTY, -1, -1);
+			if (tmp == NULL)
+			  return REG_ESPACE;
+			seq2 = tre_ast_new_union(mem, tmp, seq2);
+			if (seq2 == NULL)
+			  return REG_ESPACE;
+		      }
+		  }
+
+		pos_add = pos_add_save;
+		if (seq1 == NULL)
+		  seq1 = seq2;
+		else if (seq2 != NULL)
+		  seq1 = tre_ast_new_catenation(mem, seq1, seq2);
+		if (seq1 == NULL)
+		  return REG_ESPACE;
+		node->obj = seq1->obj;
+		node->type = seq1->type;
+	      }
+
+	    iter_depth--;
+	    pos_add_total += pos_add - pos_add_last;
+	    if (iter_depth == 0)
+	      pos_add = pos_add_total;
+
+	    break;
+	  }
+	default:
+	  assert(0);
+	  break;
+	}
+    }
+
+  *position += pos_add_total;
+
+  /* `max_pos' should never be larger than `*position' if the above
+     code works, but just an extra safeguard let's make sure
+     `*position' is set large enough so enough memory will be
+     allocated for the transition table. */
+  if (max_pos > *position)
+    *position = max_pos;
+
+  return status;
+}
+
+static tre_pos_and_tags_t *
+tre_set_empty(tre_mem_t mem)
+{
+  tre_pos_and_tags_t *new_set;
+
+  new_set = tre_mem_calloc(mem, sizeof(*new_set));
+  if (new_set == NULL)
+    return NULL;
+
+  new_set[0].position = -1;
+  new_set[0].code_min = -1;
+  new_set[0].code_max = -1;
+
+  return new_set;
+}
+
+static tre_pos_and_tags_t *
+tre_set_one(tre_mem_t mem, int position, int code_min, int code_max,
+	    tre_ctype_t class, tre_ctype_t *neg_classes, int backref)
+{
+  tre_pos_and_tags_t *new_set;
+
+  new_set = tre_mem_calloc(mem, sizeof(*new_set) * 2);
+  if (new_set == NULL)
+    return NULL;
+
+  new_set[0].position = position;
+  new_set[0].code_min = code_min;
+  new_set[0].code_max = code_max;
+  new_set[0].class = class;
+  new_set[0].neg_classes = neg_classes;
+  new_set[0].backref = backref;
+  new_set[1].position = -1;
+  new_set[1].code_min = -1;
+  new_set[1].code_max = -1;
+
+  return new_set;
+}
+
+static tre_pos_and_tags_t *
+tre_set_union(tre_mem_t mem, tre_pos_and_tags_t *set1, tre_pos_and_tags_t *set2,
+	      int *tags, int assertions)
+{
+  int s1, s2, i, j;
+  tre_pos_and_tags_t *new_set;
+  int *new_tags;
+  int num_tags;
+
+  for (num_tags = 0; tags != NULL && tags[num_tags] >= 0; num_tags++);
+  for (s1 = 0; set1[s1].position >= 0; s1++);
+  for (s2 = 0; set2[s2].position >= 0; s2++);
+  new_set = tre_mem_calloc(mem, sizeof(*new_set) * (s1 + s2 + 1));
+  if (!new_set )
+    return NULL;
+
+  for (s1 = 0; set1[s1].position >= 0; s1++)
+    {
+      new_set[s1].position = set1[s1].position;
+      new_set[s1].code_min = set1[s1].code_min;
+      new_set[s1].code_max = set1[s1].code_max;
+      new_set[s1].assertions = set1[s1].assertions | assertions;
+      new_set[s1].class = set1[s1].class;
+      new_set[s1].neg_classes = set1[s1].neg_classes;
+      new_set[s1].backref = set1[s1].backref;
+      if (set1[s1].tags == NULL && tags == NULL)
+	new_set[s1].tags = NULL;
+      else
+	{
+	  for (i = 0; set1[s1].tags != NULL && set1[s1].tags[i] >= 0; i++);
+	  new_tags = tre_mem_alloc(mem, (sizeof(*new_tags)
+					 * (i + num_tags + 1)));
+	  if (new_tags == NULL)
+	    return NULL;
+	  for (j = 0; j < i; j++)
+	    new_tags[j] = set1[s1].tags[j];
+	  for (i = 0; i < num_tags; i++)
+	    new_tags[j + i] = tags[i];
+	  new_tags[j + i] = -1;
+	  new_set[s1].tags = new_tags;
+	}
+    }
+
+  for (s2 = 0; set2[s2].position >= 0; s2++)
+    {
+      new_set[s1 + s2].position = set2[s2].position;
+      new_set[s1 + s2].code_min = set2[s2].code_min;
+      new_set[s1 + s2].code_max = set2[s2].code_max;
+      /* XXX - why not | assertions here as well? */
+      new_set[s1 + s2].assertions = set2[s2].assertions;
+      new_set[s1 + s2].class = set2[s2].class;
+      new_set[s1 + s2].neg_classes = set2[s2].neg_classes;
+      new_set[s1 + s2].backref = set2[s2].backref;
+      if (set2[s2].tags == NULL)
+	new_set[s1 + s2].tags = NULL;
+      else
+	{
+	  for (i = 0; set2[s2].tags[i] >= 0; i++);
+	  new_tags = tre_mem_alloc(mem, sizeof(*new_tags) * (i + 1));
+	  if (new_tags == NULL)
+	    return NULL;
+	  for (j = 0; j < i; j++)
+	    new_tags[j] = set2[s2].tags[j];
+	  new_tags[j] = -1;
+	  new_set[s1 + s2].tags = new_tags;
+	}
+    }
+  new_set[s1 + s2].position = -1;
+  return new_set;
+}
+
+/* Finds the empty path through `node' which is the one that should be
+   taken according to POSIX.2 rules, and adds the tags on that path to
+   `tags'.   `tags' may be NULL.  If `num_tags_seen' is not NULL, it is
+   set to the number of tags seen on the path. */
+static reg_errcode_t
+tre_match_empty(tre_stack_t *stack, tre_ast_node_t *node, int *tags,
+		int *assertions, int *num_tags_seen)
+{
+  tre_literal_t *lit;
+  tre_union_t *uni;
+  tre_catenation_t *cat;
+  tre_iteration_t *iter;
+  int i;
+  int bottom = tre_stack_num_objects(stack);
+  reg_errcode_t status = REG_OK;
+  if (num_tags_seen)
+    *num_tags_seen = 0;
+
+  status = tre_stack_push_voidptr(stack, node);
+
+  /* Walk through the tree recursively. */
+  while (status == REG_OK && tre_stack_num_objects(stack) > bottom)
+    {
+      node = tre_stack_pop_voidptr(stack);
+
+      switch (node->type)
+	{
+	case LITERAL:
+	  lit = (tre_literal_t *)node->obj;
+	  switch (lit->code_min)
+	    {
+	    case TAG:
+	      if (lit->code_max >= 0)
+		{
+		  if (tags != NULL)
+		    {
+		      /* Add the tag to `tags'. */
+		      for (i = 0; tags[i] >= 0; i++)
+			if (tags[i] == lit->code_max)
+			  break;
+		      if (tags[i] < 0)
+			{
+			  tags[i] = lit->code_max;
+			  tags[i + 1] = -1;
+			}
+		    }
+		  if (num_tags_seen)
+		    (*num_tags_seen)++;
+		}
+	      break;
+	    case ASSERTION:
+	      assert(lit->code_max >= 1
+		     || lit->code_max <= ASSERT_LAST);
+	      if (assertions != NULL)
+		*assertions |= lit->code_max;
+	      break;
+	    case EMPTY:
+	      break;
+	    default:
+	      assert(0);
+	      break;
+	    }
+	  break;
+
+	case UNION:
+	  /* Subexpressions starting earlier take priority over ones
+	     starting later, so we prefer the left subexpression over the
+	     right subexpression. */
+	  uni = (tre_union_t *)node->obj;
+	  if (uni->left->nullable)
+	    STACK_PUSHX(stack, voidptr, uni->left)
+	  else if (uni->right->nullable)
+	    STACK_PUSHX(stack, voidptr, uni->right)
+	  else
+	    assert(0);
+	  break;
+
+	case CATENATION:
+	  /* The path must go through both children. */
+	  cat = (tre_catenation_t *)node->obj;
+	  assert(cat->left->nullable);
+	  assert(cat->right->nullable);
+	  STACK_PUSHX(stack, voidptr, cat->left);
+	  STACK_PUSHX(stack, voidptr, cat->right);
+	  break;
+
+	case ITERATION:
+	  /* A match with an empty string is preferred over no match at
+	     all, so we go through the argument if possible. */
+	  iter = (tre_iteration_t *)node->obj;
+	  if (iter->arg->nullable)
+	    STACK_PUSHX(stack, voidptr, iter->arg);
+	  break;
+
+	default:
+	  assert(0);
+	  break;
+	}
+    }
+
+  return status;
+}
+
+
+typedef enum {
+  NFL_RECURSE,
+  NFL_POST_UNION,
+  NFL_POST_CATENATION,
+  NFL_POST_ITERATION
+} tre_nfl_stack_symbol_t;
+
+
+/* Computes and fills in the fields `nullable', `firstpos', and `lastpos' for
+   the nodes of the AST `tree'. */
+static reg_errcode_t
+tre_compute_nfl(tre_mem_t mem, tre_stack_t *stack, tre_ast_node_t *tree)
+{
+  int bottom = tre_stack_num_objects(stack);
+
+  STACK_PUSHR(stack, voidptr, tree);
+  STACK_PUSHR(stack, int, NFL_RECURSE);
+
+  while (tre_stack_num_objects(stack) > bottom)
+    {
+      tre_nfl_stack_symbol_t symbol;
+      tre_ast_node_t *node;
+
+      symbol = (tre_nfl_stack_symbol_t)tre_stack_pop_int(stack);
+      node = tre_stack_pop_voidptr(stack);
+      switch (symbol)
+	{
+	case NFL_RECURSE:
+	  switch (node->type)
+	    {
+	    case LITERAL:
+	      {
+		tre_literal_t *lit = (tre_literal_t *)node->obj;
+		if (IS_BACKREF(lit))
+		  {
+		    /* Back references: nullable = false, firstpos = {i},
+		       lastpos = {i}. */
+		    node->nullable = 0;
+		    node->firstpos = tre_set_one(mem, lit->position, 0,
+					     TRE_CHAR_MAX, 0, NULL, -1);
+		    if (!node->firstpos)
+		      return REG_ESPACE;
+		    node->lastpos = tre_set_one(mem, lit->position, 0,
+						TRE_CHAR_MAX, 0, NULL,
+						(int)lit->code_max);
+		    if (!node->lastpos)
+		      return REG_ESPACE;
+		  }
+		else if (lit->code_min < 0)
+		  {
+		    /* Tags, empty strings, params, and zero width assertions:
+		       nullable = true, firstpos = {}, and lastpos = {}. */
+		    node->nullable = 1;
+		    node->firstpos = tre_set_empty(mem);
+		    if (!node->firstpos)
+		      return REG_ESPACE;
+		    node->lastpos = tre_set_empty(mem);
+		    if (!node->lastpos)
+		      return REG_ESPACE;
+		  }
+		else
+		  {
+		    /* Literal at position i: nullable = false, firstpos = {i},
+		       lastpos = {i}. */
+		    node->nullable = 0;
+		    node->firstpos =
+		      tre_set_one(mem, lit->position, (int)lit->code_min,
+				  (int)lit->code_max, 0, NULL, -1);
+		    if (!node->firstpos)
+		      return REG_ESPACE;
+		    node->lastpos = tre_set_one(mem, lit->position,
+						(int)lit->code_min,
+						(int)lit->code_max,
+						lit->class, lit->neg_classes,
+						-1);
+		    if (!node->lastpos)
+		      return REG_ESPACE;
+		  }
+		break;
+	      }
+
+	    case UNION:
+	      /* Compute the attributes for the two subtrees, and after that
+		 for this node. */
+	      STACK_PUSHR(stack, voidptr, node);
+	      STACK_PUSHR(stack, int, NFL_POST_UNION);
+	      STACK_PUSHR(stack, voidptr, ((tre_union_t *)node->obj)->right);
+	      STACK_PUSHR(stack, int, NFL_RECURSE);
+	      STACK_PUSHR(stack, voidptr, ((tre_union_t *)node->obj)->left);
+	      STACK_PUSHR(stack, int, NFL_RECURSE);
+	      break;
+
+	    case CATENATION:
+	      /* Compute the attributes for the two subtrees, and after that
+		 for this node. */
+	      STACK_PUSHR(stack, voidptr, node);
+	      STACK_PUSHR(stack, int, NFL_POST_CATENATION);
+	      STACK_PUSHR(stack, voidptr, ((tre_catenation_t *)node->obj)->right);
+	      STACK_PUSHR(stack, int, NFL_RECURSE);
+	      STACK_PUSHR(stack, voidptr, ((tre_catenation_t *)node->obj)->left);
+	      STACK_PUSHR(stack, int, NFL_RECURSE);
+	      break;
+
+	    case ITERATION:
+	      /* Compute the attributes for the subtree, and after that for
+		 this node. */
+	      STACK_PUSHR(stack, voidptr, node);
+	      STACK_PUSHR(stack, int, NFL_POST_ITERATION);
+	      STACK_PUSHR(stack, voidptr, ((tre_iteration_t *)node->obj)->arg);
+	      STACK_PUSHR(stack, int, NFL_RECURSE);
+	      break;
+	    }
+	  break; /* end case: NFL_RECURSE */
+
+	case NFL_POST_UNION:
+	  {
+	    tre_union_t *uni = (tre_union_t *)node->obj;
+	    node->nullable = uni->left->nullable || uni->right->nullable;
+	    node->firstpos = tre_set_union(mem, uni->left->firstpos,
+					   uni->right->firstpos, NULL, 0);
+	    if (!node->firstpos)
+	      return REG_ESPACE;
+	    node->lastpos = tre_set_union(mem, uni->left->lastpos,
+					  uni->right->lastpos, NULL, 0);
+	    if (!node->lastpos)
+	      return REG_ESPACE;
+	    break;
+	  }
+
+	case NFL_POST_ITERATION:
+	  {
+	    tre_iteration_t *iter = (tre_iteration_t *)node->obj;
+
+	    if (iter->min == 0 || iter->arg->nullable)
+	      node->nullable = 1;
+	    else
+	      node->nullable = 0;
+	    node->firstpos = iter->arg->firstpos;
+	    node->lastpos = iter->arg->lastpos;
+	    break;
+	  }
+
+	case NFL_POST_CATENATION:
+	  {
+	    int num_tags, *tags, assertions;
+	    reg_errcode_t status;
+	    tre_catenation_t *cat = node->obj;
+	    node->nullable = cat->left->nullable && cat->right->nullable;
+
+	    /* Compute firstpos. */
+	    if (cat->left->nullable)
+	      {
+		/* The left side matches the empty string.  Make a first pass
+		   with tre_match_empty() to get the number of tags and
+		   parameters. */
+		status = tre_match_empty(stack, cat->left,
+					 NULL, NULL, &num_tags);
+		if (status != REG_OK)
+		  return status;
+		/* Allocate arrays for the tags and parameters. */
+		tags = xmalloc(sizeof(*tags) * (num_tags + 1));
+		if (!tags)
+		  return REG_ESPACE;
+		tags[0] = -1;
+		assertions = 0;
+		/* Second pass with tre_mach_empty() to get the list of
+		   tags and parameters. */
+		status = tre_match_empty(stack, cat->left, tags,
+					 &assertions, NULL);
+		if (status != REG_OK)
+		  {
+		    xfree(tags);
+		    return status;
+		  }
+		node->firstpos =
+		  tre_set_union(mem, cat->right->firstpos, cat->left->firstpos,
+				tags, assertions);
+		xfree(tags);
+		if (!node->firstpos)
+		  return REG_ESPACE;
+	      }
+	    else
+	      {
+		node->firstpos = cat->left->firstpos;
+	      }
+
+	    /* Compute lastpos. */
+	    if (cat->right->nullable)
+	      {
+		/* The right side matches the empty string.  Make a first pass
+		   with tre_match_empty() to get the number of tags and
+		   parameters. */
+		status = tre_match_empty(stack, cat->right,
+					 NULL, NULL, &num_tags);
+		if (status != REG_OK)
+		  return status;
+		/* Allocate arrays for the tags and parameters. */
+		tags = xmalloc(sizeof(int) * (num_tags + 1));
+		if (!tags)
+		  return REG_ESPACE;
+		tags[0] = -1;
+		assertions = 0;
+		/* Second pass with tre_mach_empty() to get the list of
+		   tags and parameters. */
+		status = tre_match_empty(stack, cat->right, tags,
+					 &assertions, NULL);
+		if (status != REG_OK)
+		  {
+		    xfree(tags);
+		    return status;
+		  }
+		node->lastpos =
+		  tre_set_union(mem, cat->left->lastpos, cat->right->lastpos,
+				tags, assertions);
+		xfree(tags);
+		if (!node->lastpos)
+		  return REG_ESPACE;
+	      }
+	    else
+	      {
+		node->lastpos = cat->right->lastpos;
+	      }
+	    break;
+	  }
+
+	default:
+	  assert(0);
+	  break;
+	}
+    }
+
+  return REG_OK;
+}
+
+
+/* Adds a transition from each position in `p1' to each position in `p2'. */
+static reg_errcode_t
+tre_make_trans(tre_pos_and_tags_t *p1, tre_pos_and_tags_t *p2,
+	       tre_tnfa_transition_t *transitions,
+	       int *counts, int *offs)
+{
+  tre_pos_and_tags_t *orig_p2 = p2;
+  tre_tnfa_transition_t *trans;
+  int i, j, k, l, dup, prev_p2_pos;
+
+  if (transitions != NULL)
+    while (p1->position >= 0)
+      {
+	p2 = orig_p2;
+	prev_p2_pos = -1;
+	while (p2->position >= 0)
+	  {
+	    /* Optimization: if this position was already handled, skip it. */
+	    if (p2->position == prev_p2_pos)
+	      {
+		p2++;
+		continue;
+	      }
+	    prev_p2_pos = p2->position;
+	    /* Set `trans' to point to the next unused transition from
+	       position `p1->position'. */
+	    trans = transitions + offs[p1->position];
+	    while (trans->state != NULL)
+	      {
+#if 0
+		/* If we find a previous transition from `p1->position' to
+		   `p2->position', it is overwritten.  This can happen only
+		   if there are nested loops in the regexp, like in "((a)*)*".
+		   In POSIX.2 repetition using the outer loop is always
+		   preferred over using the inner loop.	 Therefore the
+		   transition for the inner loop is useless and can be thrown
+		   away. */
+		/* XXX - The same position is used for all nodes in a bracket
+		   expression, so this optimization cannot be used (it will
+		   break bracket expressions) unless I figure out a way to
+		   detect it here. */
+		if (trans->state_id == p2->position)
+		  {
+		    break;
+		  }
+#endif
+		trans++;
+	      }
+
+	    if (trans->state == NULL)
+	      (trans + 1)->state = NULL;
+	    /* Use the character ranges, assertions, etc. from `p1' for
+	       the transition from `p1' to `p2'. */
+	    trans->code_min = p1->code_min;
+	    trans->code_max = p1->code_max;
+	    trans->state = transitions + offs[p2->position];
+	    trans->state_id = p2->position;
+	    trans->assertions = p1->assertions | p2->assertions
+	      | (p1->class ? ASSERT_CHAR_CLASS : 0)
+	      | (p1->neg_classes != NULL ? ASSERT_CHAR_CLASS_NEG : 0);
+	    if (p1->backref >= 0)
+	      {
+		assert((trans->assertions & ASSERT_CHAR_CLASS) == 0);
+		assert(p2->backref < 0);
+		trans->u.backref = p1->backref;
+		trans->assertions |= ASSERT_BACKREF;
+	      }
+	    else
+	      trans->u.class = p1->class;
+	    if (p1->neg_classes != NULL)
+	      {
+		for (i = 0; p1->neg_classes[i] != (tre_ctype_t)0; i++);
+		trans->neg_classes =
+		  xmalloc(sizeof(*trans->neg_classes) * (i + 1));
+		if (trans->neg_classes == NULL)
+		  return REG_ESPACE;
+		for (i = 0; p1->neg_classes[i] != (tre_ctype_t)0; i++)
+		  trans->neg_classes[i] = p1->neg_classes[i];
+		trans->neg_classes[i] = (tre_ctype_t)0;
+	      }
+	    else
+	      trans->neg_classes = NULL;
+
+	    /* Find out how many tags this transition has. */
+	    i = 0;
+	    if (p1->tags != NULL)
+	      while(p1->tags[i] >= 0)
+		i++;
+	    j = 0;
+	    if (p2->tags != NULL)
+	      while(p2->tags[j] >= 0)
+		j++;
+
+	    /* If we are overwriting a transition, free the old tag array. */
+	    if (trans->tags != NULL)
+	      xfree(trans->tags);
+	    trans->tags = NULL;
+
+	    /* If there were any tags, allocate an array and fill it. */
+	    if (i + j > 0)
+	      {
+		trans->tags = xmalloc(sizeof(*trans->tags) * (i + j + 1));
+		if (!trans->tags)
+		  return REG_ESPACE;
+		i = 0;
+		if (p1->tags != NULL)
+		  while(p1->tags[i] >= 0)
+		    {
+		      trans->tags[i] = p1->tags[i];
+		      i++;
+		    }
+		l = i;
+		j = 0;
+		if (p2->tags != NULL)
+		  while (p2->tags[j] >= 0)
+		    {
+		      /* Don't add duplicates. */
+		      dup = 0;
+		      for (k = 0; k < i; k++)
+			if (trans->tags[k] == p2->tags[j])
+			  {
+			    dup = 1;
+			    break;
+			  }
+		      if (!dup)
+			trans->tags[l++] = p2->tags[j];
+		      j++;
+		    }
+		trans->tags[l] = -1;
+	      }
+
+	    p2++;
+	  }
+	p1++;
+      }
+  else
+    /* Compute a maximum limit for the number of transitions leaving
+       from each state. */
+    while (p1->position >= 0)
+      {
+	p2 = orig_p2;
+	while (p2->position >= 0)
+	  {
+	    counts[p1->position]++;
+	    p2++;
+	  }
+	p1++;
+      }
+  return REG_OK;
+}
+
+/* Converts the syntax tree to a TNFA.	All the transitions in the TNFA are
+   labelled with one character range (there are no transitions on empty
+   strings).  The TNFA takes O(n^2) space in the worst case, `n' is size of
+   the regexp. */
+static reg_errcode_t
+tre_ast_to_tnfa(tre_ast_node_t *node, tre_tnfa_transition_t *transitions,
+		int *counts, int *offs)
+{
+  tre_union_t *uni;
+  tre_catenation_t *cat;
+  tre_iteration_t *iter;
+  reg_errcode_t errcode = REG_OK;
+
+  /* XXX - recurse using a stack!. */
+  switch (node->type)
+    {
+    case LITERAL:
+      break;
+    case UNION:
+      uni = (tre_union_t *)node->obj;
+      errcode = tre_ast_to_tnfa(uni->left, transitions, counts, offs);
+      if (errcode != REG_OK)
+	return errcode;
+      errcode = tre_ast_to_tnfa(uni->right, transitions, counts, offs);
+      break;
+
+    case CATENATION:
+      cat = (tre_catenation_t *)node->obj;
+      /* Add a transition from each position in cat->left->lastpos
+	 to each position in cat->right->firstpos. */
+      errcode = tre_make_trans(cat->left->lastpos, cat->right->firstpos,
+			       transitions, counts, offs);
+      if (errcode != REG_OK)
+	return errcode;
+      errcode = tre_ast_to_tnfa(cat->left, transitions, counts, offs);
+      if (errcode != REG_OK)
+	return errcode;
+      errcode = tre_ast_to_tnfa(cat->right, transitions, counts, offs);
+      break;
+
+    case ITERATION:
+      iter = (tre_iteration_t *)node->obj;
+      assert(iter->max == -1 || iter->max == 1);
+
+      if (iter->max == -1)
+	{
+	  assert(iter->min == 0 || iter->min == 1);
+	  /* Add a transition from each last position in the iterated
+	     expression to each first position. */
+	  errcode = tre_make_trans(iter->arg->lastpos, iter->arg->firstpos,
+				   transitions, counts, offs);
+	  if (errcode != REG_OK)
+	    return errcode;
+	}
+      errcode = tre_ast_to_tnfa(iter->arg, transitions, counts, offs);
+      break;
+    }
+  return errcode;
+}
+
+
+#define ERROR_EXIT(err)		  \
+  do				  \
+    {				  \
+      errcode = err;		  \
+      if (/*CONSTCOND*/1)	  \
+      	goto error_exit;	  \
+    }				  \
+ while (/*CONSTCOND*/0)
+
+
+int
+regcomp(regex_t *restrict preg, const char *restrict regex, int cflags)
+{
+  tre_stack_t *stack;
+  tre_ast_node_t *tree, *tmp_ast_l, *tmp_ast_r;
+  tre_pos_and_tags_t *p;
+  int *counts = NULL, *offs = NULL;
+  int i, add = 0;
+  tre_tnfa_transition_t *transitions, *initial;
+  tre_tnfa_t *tnfa = NULL;
+  tre_submatch_data_t *submatch_data;
+  tre_tag_direction_t *tag_directions = NULL;
+  reg_errcode_t errcode;
+  tre_mem_t mem;
+
+  /* Parse context. */
+  tre_parse_ctx_t parse_ctx;
+
+  /* Allocate a stack used throughout the compilation process for various
+     purposes. */
+  stack = tre_stack_new(512, 1024000, 128);
+  if (!stack)
+    return REG_ESPACE;
+  /* Allocate a fast memory allocator. */
+  mem = tre_mem_new();
+  if (!mem)
+    {
+      tre_stack_destroy(stack);
+      return REG_ESPACE;
+    }
+
+  /* Parse the regexp. */
+  memset(&parse_ctx, 0, sizeof(parse_ctx));
+  parse_ctx.mem = mem;
+  parse_ctx.stack = stack;
+  parse_ctx.start = regex;
+  parse_ctx.cflags = cflags;
+  parse_ctx.max_backref = -1;
+  errcode = tre_parse(&parse_ctx);
+  if (errcode != REG_OK)
+    ERROR_EXIT(errcode);
+  preg->re_nsub = parse_ctx.submatch_id - 1;
+  tree = parse_ctx.n;
+
+#ifdef TRE_DEBUG
+  tre_ast_print(tree);
+#endif /* TRE_DEBUG */
+
+  /* Referring to nonexistent subexpressions is illegal. */
+  if (parse_ctx.max_backref > (int)preg->re_nsub)
+    ERROR_EXIT(REG_ESUBREG);
+
+  /* Allocate the TNFA struct. */
+  tnfa = xcalloc(1, sizeof(tre_tnfa_t));
+  if (tnfa == NULL)
+    ERROR_EXIT(REG_ESPACE);
+  tnfa->have_backrefs = parse_ctx.max_backref >= 0;
+  tnfa->have_approx = 0;
+  tnfa->num_submatches = parse_ctx.submatch_id;
+
+  /* Set up tags for submatch addressing.  If REG_NOSUB is set and the
+     regexp does not have back references, this can be skipped. */
+  if (tnfa->have_backrefs || !(cflags & REG_NOSUB))
+    {
+
+      /* Figure out how many tags we will need. */
+      errcode = tre_add_tags(NULL, stack, tree, tnfa);
+      if (errcode != REG_OK)
+	ERROR_EXIT(errcode);
+
+      if (tnfa->num_tags > 0)
+	{
+	  tag_directions = xmalloc(sizeof(*tag_directions)
+				   * (tnfa->num_tags + 1));
+	  if (tag_directions == NULL)
+	    ERROR_EXIT(REG_ESPACE);
+	  tnfa->tag_directions = tag_directions;
+	  memset(tag_directions, -1,
+		 sizeof(*tag_directions) * (tnfa->num_tags + 1));
+	}
+      tnfa->minimal_tags = xcalloc((unsigned)tnfa->num_tags * 2 + 1,
+				   sizeof(*tnfa->minimal_tags));
+      if (tnfa->minimal_tags == NULL)
+	ERROR_EXIT(REG_ESPACE);
+
+      submatch_data = xcalloc((unsigned)parse_ctx.submatch_id,
+			      sizeof(*submatch_data));
+      if (submatch_data == NULL)
+	ERROR_EXIT(REG_ESPACE);
+      tnfa->submatch_data = submatch_data;
+
+      errcode = tre_add_tags(mem, stack, tree, tnfa);
+      if (errcode != REG_OK)
+	ERROR_EXIT(errcode);
+
+    }
+
+  /* Expand iteration nodes. */
+  errcode = tre_expand_ast(mem, stack, tree, &parse_ctx.position,
+			   tag_directions);
+  if (errcode != REG_OK)
+    ERROR_EXIT(errcode);
+
+  /* Add a dummy node for the final state.
+     XXX - For certain patterns this dummy node can be optimized away,
+	   for example "a*" or "ab*".	Figure out a simple way to detect
+	   this possibility. */
+  tmp_ast_l = tree;
+  tmp_ast_r = tre_ast_new_literal(mem, 0, 0, parse_ctx.position++);
+  if (tmp_ast_r == NULL)
+    ERROR_EXIT(REG_ESPACE);
+
+  tree = tre_ast_new_catenation(mem, tmp_ast_l, tmp_ast_r);
+  if (tree == NULL)
+    ERROR_EXIT(REG_ESPACE);
+
+  errcode = tre_compute_nfl(mem, stack, tree);
+  if (errcode != REG_OK)
+    ERROR_EXIT(errcode);
+
+  counts = xmalloc(sizeof(int) * parse_ctx.position);
+  if (counts == NULL)
+    ERROR_EXIT(REG_ESPACE);
+
+  offs = xmalloc(sizeof(int) * parse_ctx.position);
+  if (offs == NULL)
+    ERROR_EXIT(REG_ESPACE);
+
+  for (i = 0; i < parse_ctx.position; i++)
+    counts[i] = 0;
+  tre_ast_to_tnfa(tree, NULL, counts, NULL);
+
+  add = 0;
+  for (i = 0; i < parse_ctx.position; i++)
+    {
+      offs[i] = add;
+      add += counts[i] + 1;
+      counts[i] = 0;
+    }
+  transitions = xcalloc((unsigned)add + 1, sizeof(*transitions));
+  if (transitions == NULL)
+    ERROR_EXIT(REG_ESPACE);
+  tnfa->transitions = transitions;
+  tnfa->num_transitions = add;
+
+  errcode = tre_ast_to_tnfa(tree, transitions, counts, offs);
+  if (errcode != REG_OK)
+    ERROR_EXIT(errcode);
+
+  tnfa->firstpos_chars = NULL;
+
+  p = tree->firstpos;
+  i = 0;
+  while (p->position >= 0)
+    {
+      i++;
+      p++;
+    }
+
+  initial = xcalloc((unsigned)i + 1, sizeof(tre_tnfa_transition_t));
+  if (initial == NULL)
+    ERROR_EXIT(REG_ESPACE);
+  tnfa->initial = initial;
+
+  i = 0;
+  for (p = tree->firstpos; p->position >= 0; p++)
+    {
+      initial[i].state = transitions + offs[p->position];
+      initial[i].state_id = p->position;
+      initial[i].tags = NULL;
+      /* Copy the arrays p->tags, and p->params, they are allocated
+	 from a tre_mem object. */
+      if (p->tags)
+	{
+	  int j;
+	  for (j = 0; p->tags[j] >= 0; j++);
+	  initial[i].tags = xmalloc(sizeof(*p->tags) * (j + 1));
+	  if (!initial[i].tags)
+	    ERROR_EXIT(REG_ESPACE);
+	  memcpy(initial[i].tags, p->tags, sizeof(*p->tags) * (j + 1));
+	}
+      initial[i].assertions = p->assertions;
+      i++;
+    }
+  initial[i].state = NULL;
+
+  tnfa->num_transitions = add;
+  tnfa->final = transitions + offs[tree->lastpos[0].position];
+  tnfa->num_states = parse_ctx.position;
+  tnfa->cflags = cflags;
+
+  tre_mem_destroy(mem);
+  tre_stack_destroy(stack);
+  xfree(counts);
+  xfree(offs);
+
+  preg->TRE_REGEX_T_FIELD = (void *)tnfa;
+  return REG_OK;
+
+ error_exit:
+  /* Free everything that was allocated and return the error code. */
+  tre_mem_destroy(mem);
+  if (stack != NULL)
+    tre_stack_destroy(stack);
+  if (counts != NULL)
+    xfree(counts);
+  if (offs != NULL)
+    xfree(offs);
+  preg->TRE_REGEX_T_FIELD = (void *)tnfa;
+  regfree(preg);
+  return errcode;
+}
+
+
+
+
+void
+regfree(regex_t *preg)
+{
+  tre_tnfa_t *tnfa;
+  unsigned int i;
+  tre_tnfa_transition_t *trans;
+
+  tnfa = (void *)preg->TRE_REGEX_T_FIELD;
+  if (!tnfa)
+    return;
+
+  for (i = 0; i < tnfa->num_transitions; i++)
+    if (tnfa->transitions[i].state)
+      {
+	if (tnfa->transitions[i].tags)
+	  xfree(tnfa->transitions[i].tags);
+	if (tnfa->transitions[i].neg_classes)
+	  xfree(tnfa->transitions[i].neg_classes);
+      }
+  if (tnfa->transitions)
+    xfree(tnfa->transitions);
+
+  if (tnfa->initial)
+    {
+      for (trans = tnfa->initial; trans->state; trans++)
+	{
+	  if (trans->tags)
+	    xfree(trans->tags);
+	}
+      xfree(tnfa->initial);
+    }
+
+  if (tnfa->submatch_data)
+    {
+      for (i = 0; i < tnfa->num_submatches; i++)
+	if (tnfa->submatch_data[i].parents)
+	  xfree(tnfa->submatch_data[i].parents);
+      xfree(tnfa->submatch_data);
+    }
+
+  if (tnfa->tag_directions)
+    xfree(tnfa->tag_directions);
+  if (tnfa->firstpos_chars)
+    xfree(tnfa->firstpos_chars);
+  if (tnfa->minimal_tags)
+    xfree(tnfa->minimal_tags);
+  xfree(tnfa);
+}
diff --git a/vendor/tre-regex/regerror.c b/vendor/tre-regex/regerror.c
new file mode 100644
index 0000000..a3ebe21
--- /dev/null
+++ b/vendor/tre-regex/regerror.c
@@ -0,0 +1,36 @@
+#include <string.h>
+#include "regex.h"
+#include <stdio.h>
+
+/* Error message strings for error codes listed in `regex.h'.  This list
+   needs to be in sync with the codes listed there, naturally. */
+
+/* Converted to single string by Rich Felker to remove the need for
+ * data relocations at runtime, 27 Feb 2006. */
+
+static const char messages[] = {
+  "No error\0"
+  "No match\0"
+  "Invalid regexp\0"
+  "Unknown collating element\0"
+  "Unknown character class name\0"
+  "Trailing backslash\0"
+  "Invalid back reference\0"
+  "Missing ']'\0"
+  "Missing ')'\0"
+  "Missing '}'\0"
+  "Invalid contents of {}\0"
+  "Invalid character range\0"
+  "Out of memory\0"
+  "Repetition not preceded by valid expression\0"
+  "\0Unknown error"
+};
+
+size_t regerror(int e, const regex_t *restrict preg, char *restrict buf, size_t size)
+{
+	const char *s;
+	(void)preg;
+	for (s=messages; e && *s; e--, s+=strlen(s)+1);
+	if (!*s) s++;
+	return 1+snprintf(buf, size, "%s", s);
+}
diff --git a/vendor/tre-regex/regex.h b/vendor/tre-regex/regex.h
new file mode 100644
index 0000000..73bb431
--- /dev/null
+++ b/vendor/tre-regex/regex.h
@@ -0,0 +1,62 @@
+/* POSIX <regex.h> for platforms without one (MinGW). The engine is musl's
+ * TRE (vendor/tre-regex, musl 1.2.5) patched to decode UTF-8 itself, so
+ * patterns and subjects are UTF-8 regardless of wchar_t width. */
+#ifndef _REGEX_H
+#define _REGEX_H
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef ptrdiff_t regoff_t;
+
+typedef struct re_pattern_buffer {
+	size_t re_nsub;
+	void *__opaque, *__padding[4];
+	size_t __nsub2;
+	char __padding2;
+} regex_t;
+
+typedef struct {
+	regoff_t rm_so;
+	regoff_t rm_eo;
+} regmatch_t;
+
+#define REG_EXTENDED    1
+#define REG_ICASE       2
+#define REG_NEWLINE     4
+#define REG_NOSUB       8
+
+#define REG_NOTBOL      1
+#define REG_NOTEOL      2
+
+#define REG_OK          0
+#define REG_NOMATCH     1
+#define REG_BADPAT      2
+#define REG_ECOLLATE    3
+#define REG_ECTYPE      4
+#define REG_EESCAPE     5
+#define REG_ESUBREG     6
+#define REG_EBRACK      7
+#define REG_EPAREN      8
+#define REG_EBRACE      9
+#define REG_BADBR       10
+#define REG_ERANGE      11
+#define REG_ESPACE      12
+#define REG_BADRPT      13
+
+#define REG_ENOSYS      -1
+
+int regcomp(regex_t *__restrict, const char *__restrict, int);
+int regexec(const regex_t *__restrict, const char *__restrict, size_t, regmatch_t *__restrict, int);
+void regfree(regex_t *);
+
+size_t regerror(int, const regex_t *__restrict, char *__restrict, size_t);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/vendor/tre-regex/regexec.c b/vendor/tre-regex/regexec.c
new file mode 100644
index 0000000..e0fcd8a
--- /dev/null
+++ b/vendor/tre-regex/regexec.c
@@ -0,0 +1,1028 @@
+/*
+  regexec.c - TRE POSIX compatible matching functions (and more).
+
+  Copyright (c) 2001-2009 Ville Laurikari <vl@iki.fi>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions
+  are met:
+
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS
+  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+  A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
+  HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+*/
+
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+#include <wctype.h>
+#include <limits.h>
+#include <stdint.h>
+
+#include "regex.h"
+
+#include "tre.h"
+
+#include <assert.h>
+
+static void
+tre_fill_pmatch(size_t nmatch, regmatch_t pmatch[], int cflags,
+		const tre_tnfa_t *tnfa, regoff_t *tags, regoff_t match_eo);
+
+/***********************************************************************
+ from tre-match-utils.h
+***********************************************************************/
+
+#define GET_NEXT_WCHAR() do {                                                 \
+    prev_c = next_c; pos += pos_add_next;                                     \
+    if ((pos_add_next = tre_mbtowc(&next_c, str_byte, 4)) <= 0) {        \
+        if (pos_add_next < 0) { ret = REG_NOMATCH; goto error_exit; }         \
+        else pos_add_next++;                                                  \
+    }                                                                         \
+    str_byte += pos_add_next;                                                 \
+  } while (0)
+
+#define IS_WORD_CHAR(c)	 ((c) == L'_' || tre_isalnum(c))
+
+#define CHECK_ASSERTIONS(assertions)					      \
+  (((assertions & ASSERT_AT_BOL)					      \
+    && (pos > 0 || reg_notbol)						      \
+    && (prev_c != L'\n' || !reg_newline))				      \
+   || ((assertions & ASSERT_AT_EOL)					      \
+       && (next_c != L'\0' || reg_noteol)				      \
+       && (next_c != L'\n' || !reg_newline))				      \
+   || ((assertions & ASSERT_AT_BOW)					      \
+       && (IS_WORD_CHAR(prev_c) || !IS_WORD_CHAR(next_c)))	              \
+   || ((assertions & ASSERT_AT_EOW)					      \
+       && (!IS_WORD_CHAR(prev_c) || IS_WORD_CHAR(next_c)))		      \
+   || ((assertions & ASSERT_AT_WB)					      \
+       && (pos != 0 && next_c != L'\0'					      \
+	   && IS_WORD_CHAR(prev_c) == IS_WORD_CHAR(next_c)))		      \
+   || ((assertions & ASSERT_AT_WB_NEG)					      \
+       && (pos == 0 || next_c == L'\0'					      \
+	   || IS_WORD_CHAR(prev_c) != IS_WORD_CHAR(next_c))))
+
+#define CHECK_CHAR_CLASSES(trans_i, tnfa, eflags)                             \
+  (((trans_i->assertions & ASSERT_CHAR_CLASS)                                 \
+       && !(tnfa->cflags & REG_ICASE)                                         \
+       && !tre_isctype((tre_cint_t)prev_c, trans_i->u.class))                 \
+    || ((trans_i->assertions & ASSERT_CHAR_CLASS)                             \
+        && (tnfa->cflags & REG_ICASE)                                         \
+        && !tre_isctype(tre_tolower((tre_cint_t)prev_c),trans_i->u.class)     \
+	&& !tre_isctype(tre_toupper((tre_cint_t)prev_c),trans_i->u.class))    \
+    || ((trans_i->assertions & ASSERT_CHAR_CLASS_NEG)                         \
+        && tre_neg_char_classes_match(trans_i->neg_classes,(tre_cint_t)prev_c,\
+                                      tnfa->cflags & REG_ICASE)))
+
+
+
+
+/* Returns 1 if `t1' wins `t2', 0 otherwise. */
+static int
+tre_tag_order(int num_tags, tre_tag_direction_t *tag_directions,
+	      regoff_t *t1, regoff_t *t2)
+{
+  int i;
+  for (i = 0; i < num_tags; i++)
+    {
+      if (tag_directions[i] == TRE_TAG_MINIMIZE)
+	{
+	  if (t1[i] < t2[i])
+	    return 1;
+	  if (t1[i] > t2[i])
+	    return 0;
+	}
+      else
+	{
+	  if (t1[i] > t2[i])
+	    return 1;
+	  if (t1[i] < t2[i])
+	    return 0;
+	}
+    }
+  /*  assert(0);*/
+  return 0;
+}
+
+static int
+tre_neg_char_classes_match(tre_ctype_t *classes, tre_cint_t wc, int icase)
+{
+  while (*classes != (tre_ctype_t)0)
+    if ((!icase && tre_isctype(wc, *classes))
+	|| (icase && (tre_isctype(tre_toupper(wc), *classes)
+		      || tre_isctype(tre_tolower(wc), *classes))))
+      return 1; /* Match. */
+    else
+      classes++;
+  return 0; /* No match. */
+}
+
+
+/***********************************************************************
+ from tre-match-parallel.c
+***********************************************************************/
+
+/*
+  This algorithm searches for matches basically by reading characters
+  in the searched string one by one, starting at the beginning.	 All
+  matching paths in the TNFA are traversed in parallel.	 When two or
+  more paths reach the same state, exactly one is chosen according to
+  tag ordering rules; if returning submatches is not required it does
+  not matter which path is chosen.
+
+  The worst case time required for finding the leftmost and longest
+  match, or determining that there is no match, is always linearly
+  dependent on the length of the text being searched.
+
+  This algorithm cannot handle TNFAs with back referencing nodes.
+  See `tre-match-backtrack.c'.
+*/
+
+typedef struct {
+  tre_tnfa_transition_t *state;
+  regoff_t *tags;
+} tre_tnfa_reach_t;
+
+typedef struct {
+  regoff_t pos;
+  regoff_t **tags;
+} tre_reach_pos_t;
+
+
+static reg_errcode_t
+tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string,
+		      regoff_t *match_tags, int eflags,
+		      regoff_t *match_end_ofs)
+{
+  /* State variables required by GET_NEXT_WCHAR. */
+  tre_char_t prev_c = 0, next_c = 0;
+  const char *str_byte = string;
+  regoff_t pos = -1;
+  regoff_t pos_add_next = 1;
+#ifdef TRE_MBSTATE
+  mbstate_t mbstate;
+#endif /* TRE_MBSTATE */
+  int reg_notbol = eflags & REG_NOTBOL;
+  int reg_noteol = eflags & REG_NOTEOL;
+  int reg_newline = tnfa->cflags & REG_NEWLINE;
+  reg_errcode_t ret;
+
+  char *buf;
+  tre_tnfa_transition_t *trans_i;
+  tre_tnfa_reach_t *reach, *reach_next, *reach_i, *reach_next_i;
+  tre_reach_pos_t *reach_pos;
+  int *tag_i;
+  int num_tags, i;
+
+  regoff_t match_eo = -1;	   /* end offset of match (-1 if no match found yet) */
+  int new_match = 0;
+  regoff_t *tmp_tags = NULL;
+  regoff_t *tmp_iptr;
+
+#ifdef TRE_MBSTATE
+  memset(&mbstate, '\0', sizeof(mbstate));
+#endif /* TRE_MBSTATE */
+
+  if (!match_tags)
+    num_tags = 0;
+  else
+    num_tags = tnfa->num_tags;
+
+  /* Allocate memory for temporary data required for matching.	This needs to
+     be done for every matching operation to be thread safe.  This allocates
+     everything in a single large block with calloc(). */
+  {
+    size_t tbytes, rbytes, pbytes, xbytes, total_bytes;
+    char *tmp_buf;
+
+    /* Ensure that tbytes and xbytes*num_states cannot overflow, and that
+     * they don't contribute more than 1/8 of SIZE_MAX to total_bytes. */
+    if (num_tags > SIZE_MAX/(8 * sizeof(regoff_t) * tnfa->num_states))
+      return REG_ESPACE;
+
+    /* Likewise check rbytes. */
+    if (tnfa->num_states+1 > SIZE_MAX/(8 * sizeof(*reach_next)))
+      return REG_ESPACE;
+
+    /* Likewise check pbytes. */
+    if (tnfa->num_states > SIZE_MAX/(8 * sizeof(*reach_pos)))
+      return REG_ESPACE;
+
+    /* Compute the length of the block we need. */
+    tbytes = sizeof(*tmp_tags) * num_tags;
+    rbytes = sizeof(*reach_next) * (tnfa->num_states + 1);
+    pbytes = sizeof(*reach_pos) * tnfa->num_states;
+    xbytes = sizeof(regoff_t) * num_tags;
+    total_bytes =
+      (sizeof(long) - 1) * 4 /* for alignment paddings */
+      + (rbytes + xbytes * tnfa->num_states) * 2 + tbytes + pbytes;
+
+    /* Allocate the memory. */
+    buf = calloc(total_bytes, 1);
+    if (buf == NULL)
+      return REG_ESPACE;
+
+    /* Get the various pointers within tmp_buf (properly aligned). */
+    tmp_tags = (void *)buf;
+    tmp_buf = buf + tbytes;
+    tmp_buf += ALIGN(tmp_buf, long);
+    reach_next = (void *)tmp_buf;
+    tmp_buf += rbytes;
+    tmp_buf += ALIGN(tmp_buf, long);
+    reach = (void *)tmp_buf;
+    tmp_buf += rbytes;
+    tmp_buf += ALIGN(tmp_buf, long);
+    reach_pos = (void *)tmp_buf;
+    tmp_buf += pbytes;
+    tmp_buf += ALIGN(tmp_buf, long);
+    for (i = 0; i < tnfa->num_states; i++)
+      {
+	reach[i].tags = (void *)tmp_buf;
+	tmp_buf += xbytes;
+	reach_next[i].tags = (void *)tmp_buf;
+	tmp_buf += xbytes;
+      }
+  }
+
+  for (i = 0; i < tnfa->num_states; i++)
+    reach_pos[i].pos = -1;
+
+  GET_NEXT_WCHAR();
+  pos = 0;
+
+  reach_next_i = reach_next;
+  while (1)
+    {
+      /* If no match found yet, add the initial states to `reach_next'. */
+      if (match_eo < 0)
+	{
+	  trans_i = tnfa->initial;
+	  while (trans_i->state != NULL)
+	    {
+	      if (reach_pos[trans_i->state_id].pos < pos)
+		{
+		  if (trans_i->assertions
+		      && CHECK_ASSERTIONS(trans_i->assertions))
+		    {
+		      trans_i++;
+		      continue;
+		    }
+
+		  reach_next_i->state = trans_i->state;
+		  for (i = 0; i < num_tags; i++)
+		    reach_next_i->tags[i] = -1;
+		  tag_i = trans_i->tags;
+		  if (tag_i)
+		    while (*tag_i >= 0)
+		      {
+			if (*tag_i < num_tags)
+			  reach_next_i->tags[*tag_i] = pos;
+			tag_i++;
+		      }
+		  if (reach_next_i->state == tnfa->final)
+		    {
+		      match_eo = pos;
+		      new_match = 1;
+		      for (i = 0; i < num_tags; i++)
+			match_tags[i] = reach_next_i->tags[i];
+		    }
+		  reach_pos[trans_i->state_id].pos = pos;
+		  reach_pos[trans_i->state_id].tags = &reach_next_i->tags;
+		  reach_next_i++;
+		}
+	      trans_i++;
+	    }
+	  reach_next_i->state = NULL;
+	}
+      else
+	{
+	  if (num_tags == 0 || reach_next_i == reach_next)
+	    /* We have found a match. */
+	    break;
+	}
+
+      /* Check for end of string. */
+      if (!next_c) break;
+
+      GET_NEXT_WCHAR();
+
+      /* Swap `reach' and `reach_next'. */
+      reach_i = reach;
+      reach = reach_next;
+      reach_next = reach_i;
+
+      /* For each state in `reach', weed out states that don't fulfill the
+	 minimal matching conditions. */
+      if (tnfa->num_minimals && new_match)
+	{
+	  new_match = 0;
+	  reach_next_i = reach_next;
+	  for (reach_i = reach; reach_i->state; reach_i++)
+	    {
+	      int skip = 0;
+	      for (i = 0; tnfa->minimal_tags[i] >= 0; i += 2)
+		{
+		  int end = tnfa->minimal_tags[i];
+		  int start = tnfa->minimal_tags[i + 1];
+		  if (end >= num_tags)
+		    {
+		      skip = 1;
+		      break;
+		    }
+		  else if (reach_i->tags[start] == match_tags[start]
+			   && reach_i->tags[end] < match_tags[end])
+		    {
+		      skip = 1;
+		      break;
+		    }
+		}
+	      if (!skip)
+		{
+		  reach_next_i->state = reach_i->state;
+		  tmp_iptr = reach_next_i->tags;
+		  reach_next_i->tags = reach_i->tags;
+		  reach_i->tags = tmp_iptr;
+		  reach_next_i++;
+		}
+	    }
+	  reach_next_i->state = NULL;
+
+	  /* Swap `reach' and `reach_next'. */
+	  reach_i = reach;
+	  reach = reach_next;
+	  reach_next = reach_i;
+	}
+
+      /* For each state in `reach' see if there is a transition leaving with
+	 the current input symbol to a state not yet in `reach_next', and
+	 add the destination states to `reach_next'. */
+      reach_next_i = reach_next;
+      for (reach_i = reach; reach_i->state; reach_i++)
+	{
+	  for (trans_i = reach_i->state; trans_i->state; trans_i++)
+	    {
+	      /* Does this transition match the input symbol? */
+	      if (trans_i->code_min <= (tre_cint_t)prev_c &&
+		  trans_i->code_max >= (tre_cint_t)prev_c)
+		{
+		  if (trans_i->assertions
+		      && (CHECK_ASSERTIONS(trans_i->assertions)
+			  || CHECK_CHAR_CLASSES(trans_i, tnfa, eflags)))
+		    {
+		      continue;
+		    }
+
+		  /* Compute the tags after this transition. */
+		  for (i = 0; i < num_tags; i++)
+		    tmp_tags[i] = reach_i->tags[i];
+		  tag_i = trans_i->tags;
+		  if (tag_i != NULL)
+		    while (*tag_i >= 0)
+		      {
+			if (*tag_i < num_tags)
+			  tmp_tags[*tag_i] = pos;
+			tag_i++;
+		      }
+
+		  if (reach_pos[trans_i->state_id].pos < pos)
+		    {
+		      /* Found an unvisited node. */
+		      reach_next_i->state = trans_i->state;
+		      tmp_iptr = reach_next_i->tags;
+		      reach_next_i->tags = tmp_tags;
+		      tmp_tags = tmp_iptr;
+		      reach_pos[trans_i->state_id].pos = pos;
+		      reach_pos[trans_i->state_id].tags = &reach_next_i->tags;
+
+		      if (reach_next_i->state == tnfa->final
+			  && (match_eo == -1
+			      || (num_tags > 0
+				  && reach_next_i->tags[0] <= match_tags[0])))
+			{
+			  match_eo = pos;
+			  new_match = 1;
+			  for (i = 0; i < num_tags; i++)
+			    match_tags[i] = reach_next_i->tags[i];
+			}
+		      reach_next_i++;
+
+		    }
+		  else
+		    {
+		      assert(reach_pos[trans_i->state_id].pos == pos);
+		      /* Another path has also reached this state.  We choose
+			 the winner by examining the tag values for both
+			 paths. */
+		      if (tre_tag_order(num_tags, tnfa->tag_directions,
+					tmp_tags,
+					*reach_pos[trans_i->state_id].tags))
+			{
+			  /* The new path wins. */
+			  tmp_iptr = *reach_pos[trans_i->state_id].tags;
+			  *reach_pos[trans_i->state_id].tags = tmp_tags;
+			  if (trans_i->state == tnfa->final)
+			    {
+			      match_eo = pos;
+			      new_match = 1;
+			      for (i = 0; i < num_tags; i++)
+				match_tags[i] = tmp_tags[i];
+			    }
+			  tmp_tags = tmp_iptr;
+			}
+		    }
+		}
+	    }
+	}
+      reach_next_i->state = NULL;
+    }
+
+  *match_end_ofs = match_eo;
+  ret = match_eo >= 0 ? REG_OK : REG_NOMATCH;
+error_exit:
+  xfree(buf);
+  return ret;
+}
+
+
+
+/***********************************************************************
+ from tre-match-backtrack.c
+***********************************************************************/
+
+/*
+  This matcher is for regexps that use back referencing.  Regexp matching
+  with back referencing is an NP-complete problem on the number of back
+  references.  The easiest way to match them is to use a backtracking
+  routine which basically goes through all possible paths in the TNFA
+  and chooses the one which results in the best (leftmost and longest)
+  match.  This can be spectacularly expensive and may run out of stack
+  space, but there really is no better known generic algorithm.	 Quoting
+  Henry Spencer from comp.compilers:
+  <URL: http://compilers.iecc.com/comparch/article/93-03-102>
+
+    POSIX.2 REs require longest match, which is really exciting to
+    implement since the obsolete ("basic") variant also includes
+    \<digit>.  I haven't found a better way of tackling this than doing
+    a preliminary match using a DFA (or simulation) on a modified RE
+    that just replicates subREs for \<digit>, and then doing a
+    backtracking match to determine whether the subRE matches were
+    right.  This can be rather slow, but I console myself with the
+    thought that people who use \<digit> deserve very slow execution.
+    (Pun unintentional but very appropriate.)
+
+*/
+
+typedef struct {
+  regoff_t pos;
+  const char *str_byte;
+  tre_tnfa_transition_t *state;
+  int state_id;
+  int next_c;
+  regoff_t *tags;
+#ifdef TRE_MBSTATE
+  mbstate_t mbstate;
+#endif /* TRE_MBSTATE */
+} tre_backtrack_item_t;
+
+typedef struct tre_backtrack_struct {
+  tre_backtrack_item_t item;
+  struct tre_backtrack_struct *prev;
+  struct tre_backtrack_struct *next;
+} *tre_backtrack_t;
+
+#ifdef TRE_MBSTATE
+#define BT_STACK_MBSTATE_IN  stack->item.mbstate = (mbstate)
+#define BT_STACK_MBSTATE_OUT (mbstate) = stack->item.mbstate
+#else /* !TRE_MBSTATE */
+#define BT_STACK_MBSTATE_IN
+#define BT_STACK_MBSTATE_OUT
+#endif /* !TRE_MBSTATE */
+
+#define tre_bt_mem_new		  tre_mem_new
+#define tre_bt_mem_alloc	  tre_mem_alloc
+#define tre_bt_mem_destroy	  tre_mem_destroy
+
+
+#define BT_STACK_PUSH(_pos, _str_byte, _str_wide, _state, _state_id, _next_c, _tags, _mbstate) \
+  do									      \
+    {									      \
+      int i;								      \
+      if (!stack->next)							      \
+	{								      \
+	  tre_backtrack_t s;						      \
+	  s = tre_bt_mem_alloc(mem, sizeof(*s));			      \
+	  if (!s)							      \
+	    {								      \
+	      tre_bt_mem_destroy(mem);					      \
+	      if (tags)							      \
+		xfree(tags);						      \
+	      if (pmatch)						      \
+		xfree(pmatch);						      \
+	      if (states_seen)						      \
+		xfree(states_seen);					      \
+	      return REG_ESPACE;					      \
+	    }								      \
+	  s->prev = stack;						      \
+	  s->next = NULL;						      \
+	  s->item.tags = tre_bt_mem_alloc(mem,				      \
+					  sizeof(*tags) * tnfa->num_tags);    \
+	  if (!s->item.tags)						      \
+	    {								      \
+	      tre_bt_mem_destroy(mem);					      \
+	      if (tags)							      \
+		xfree(tags);						      \
+	      if (pmatch)						      \
+		xfree(pmatch);						      \
+	      if (states_seen)						      \
+		xfree(states_seen);					      \
+	      return REG_ESPACE;					      \
+	    }								      \
+	  stack->next = s;						      \
+	  stack = s;							      \
+	}								      \
+      else								      \
+	stack = stack->next;						      \
+      stack->item.pos = (_pos);						      \
+      stack->item.str_byte = (_str_byte);				      \
+      stack->item.state = (_state);					      \
+      stack->item.state_id = (_state_id);				      \
+      stack->item.next_c = (_next_c);					      \
+      for (i = 0; i < tnfa->num_tags; i++)				      \
+	stack->item.tags[i] = (_tags)[i];				      \
+      BT_STACK_MBSTATE_IN;						      \
+    }									      \
+  while (0)
+
+#define BT_STACK_POP()							      \
+  do									      \
+    {									      \
+      int i;								      \
+      assert(stack->prev);						      \
+      pos = stack->item.pos;						      \
+      str_byte = stack->item.str_byte;					      \
+      state = stack->item.state;					      \
+      next_c = stack->item.next_c;					      \
+      for (i = 0; i < tnfa->num_tags; i++)				      \
+	tags[i] = stack->item.tags[i];					      \
+      BT_STACK_MBSTATE_OUT;						      \
+      stack = stack->prev;						      \
+    }									      \
+  while (0)
+
+#undef MIN
+#define MIN(a, b) ((a) <= (b) ? (a) : (b))
+
+static reg_errcode_t
+tre_tnfa_run_backtrack(const tre_tnfa_t *tnfa, const void *string,
+		       regoff_t *match_tags, int eflags, regoff_t *match_end_ofs)
+{
+  /* State variables required by GET_NEXT_WCHAR. */
+  tre_char_t prev_c = 0, next_c = 0;
+  const char *str_byte = string;
+  regoff_t pos = 0;
+  regoff_t pos_add_next = 1;
+#ifdef TRE_MBSTATE
+  mbstate_t mbstate;
+#endif /* TRE_MBSTATE */
+  int reg_notbol = eflags & REG_NOTBOL;
+  int reg_noteol = eflags & REG_NOTEOL;
+  int reg_newline = tnfa->cflags & REG_NEWLINE;
+
+  /* These are used to remember the necessary values of the above
+     variables to return to the position where the current search
+     started from. */
+  int next_c_start;
+  const char *str_byte_start;
+  regoff_t pos_start = -1;
+#ifdef TRE_MBSTATE
+  mbstate_t mbstate_start;
+#endif /* TRE_MBSTATE */
+
+  /* End offset of best match so far, or -1 if no match found yet. */
+  regoff_t match_eo = -1;
+  /* Tag arrays. */
+  int *next_tags;
+  regoff_t *tags = NULL;
+  /* Current TNFA state. */
+  tre_tnfa_transition_t *state;
+  int *states_seen = NULL;
+
+  /* Memory allocator to for allocating the backtracking stack. */
+  tre_mem_t mem = tre_bt_mem_new();
+
+  /* The backtracking stack. */
+  tre_backtrack_t stack;
+
+  tre_tnfa_transition_t *trans_i;
+  regmatch_t *pmatch = NULL;
+  int ret;
+
+#ifdef TRE_MBSTATE
+  memset(&mbstate, '\0', sizeof(mbstate));
+#endif /* TRE_MBSTATE */
+
+  if (!mem)
+    return REG_ESPACE;
+  stack = tre_bt_mem_alloc(mem, sizeof(*stack));
+  if (!stack)
+    {
+      ret = REG_ESPACE;
+      goto error_exit;
+    }
+  stack->prev = NULL;
+  stack->next = NULL;
+
+  if (tnfa->num_tags)
+    {
+      tags = xmalloc(sizeof(*tags) * tnfa->num_tags);
+      if (!tags)
+	{
+	  ret = REG_ESPACE;
+	  goto error_exit;
+	}
+    }
+  if (tnfa->num_submatches)
+    {
+      pmatch = xmalloc(sizeof(*pmatch) * tnfa->num_submatches);
+      if (!pmatch)
+	{
+	  ret = REG_ESPACE;
+	  goto error_exit;
+	}
+    }
+  if (tnfa->num_states)
+    {
+      states_seen = xmalloc(sizeof(*states_seen) * tnfa->num_states);
+      if (!states_seen)
+	{
+	  ret = REG_ESPACE;
+	  goto error_exit;
+	}
+    }
+
+ retry:
+  {
+    int i;
+    for (i = 0; i < tnfa->num_tags; i++)
+      {
+	tags[i] = -1;
+	if (match_tags)
+	  match_tags[i] = -1;
+      }
+    for (i = 0; i < tnfa->num_states; i++)
+      states_seen[i] = 0;
+  }
+
+  state = NULL;
+  pos = pos_start;
+  GET_NEXT_WCHAR();
+  pos_start = pos;
+  next_c_start = next_c;
+  str_byte_start = str_byte;
+#ifdef TRE_MBSTATE
+  mbstate_start = mbstate;
+#endif /* TRE_MBSTATE */
+
+  /* Handle initial states. */
+  next_tags = NULL;
+  for (trans_i = tnfa->initial; trans_i->state; trans_i++)
+    {
+      if (trans_i->assertions && CHECK_ASSERTIONS(trans_i->assertions))
+	{
+	  continue;
+	}
+      if (state == NULL)
+	{
+	  /* Start from this state. */
+	  state = trans_i->state;
+	  next_tags = trans_i->tags;
+	}
+      else
+	{
+	  /* Backtrack to this state. */
+	  BT_STACK_PUSH(pos, str_byte, 0, trans_i->state,
+			trans_i->state_id, next_c, tags, mbstate);
+	  {
+	    int *tmp = trans_i->tags;
+	    if (tmp)
+	      while (*tmp >= 0)
+		stack->item.tags[*tmp++] = pos;
+	  }
+	}
+    }
+
+  if (next_tags)
+    for (; *next_tags >= 0; next_tags++)
+      tags[*next_tags] = pos;
+
+
+  if (state == NULL)
+    goto backtrack;
+
+  while (1)
+    {
+      tre_tnfa_transition_t *next_state;
+      int empty_br_match;
+
+      if (state == tnfa->final)
+	{
+	  if (match_eo < pos
+	      || (match_eo == pos
+		  && match_tags
+		  && tre_tag_order(tnfa->num_tags, tnfa->tag_directions,
+				   tags, match_tags)))
+	    {
+	      int i;
+	      /* This match wins the previous match. */
+	      match_eo = pos;
+	      if (match_tags)
+		for (i = 0; i < tnfa->num_tags; i++)
+		  match_tags[i] = tags[i];
+	    }
+	  /* Our TNFAs never have transitions leaving from the final state,
+	     so we jump right to backtracking. */
+	  goto backtrack;
+	}
+
+      /* Go to the next character in the input string. */
+      empty_br_match = 0;
+      trans_i = state;
+      if (trans_i->state && trans_i->assertions & ASSERT_BACKREF)
+	{
+	  /* This is a back reference state.  All transitions leaving from
+	     this state have the same back reference "assertion".  Instead
+	     of reading the next character, we match the back reference. */
+	  regoff_t so, eo;
+	  int bt = trans_i->u.backref;
+	  regoff_t bt_len;
+	  int result;
+
+	  /* Get the substring we need to match against.  Remember to
+	     turn off REG_NOSUB temporarily. */
+	  tre_fill_pmatch(bt + 1, pmatch, tnfa->cflags & ~REG_NOSUB,
+			  tnfa, tags, pos);
+	  so = pmatch[bt].rm_so;
+	  eo = pmatch[bt].rm_eo;
+	  bt_len = eo - so;
+
+	  result = strncmp((const char*)string + so, str_byte - 1,
+				 (size_t)bt_len);
+
+	  if (result == 0)
+	    {
+	      /* Back reference matched.  Check for infinite loop. */
+	      if (bt_len == 0)
+		empty_br_match = 1;
+	      if (empty_br_match && states_seen[trans_i->state_id])
+		{
+		  goto backtrack;
+		}
+
+	      states_seen[trans_i->state_id] = empty_br_match;
+
+	      /* Advance in input string and resync `prev_c', `next_c'
+		 and pos. */
+	      str_byte += bt_len - 1;
+	      pos += bt_len - 1;
+	      GET_NEXT_WCHAR();
+	    }
+	  else
+	    {
+	      goto backtrack;
+	    }
+	}
+      else
+	{
+	  /* Check for end of string. */
+	  if (next_c == L'\0')
+		goto backtrack;
+
+	  /* Read the next character. */
+	  GET_NEXT_WCHAR();
+	}
+
+      next_state = NULL;
+      for (trans_i = state; trans_i->state; trans_i++)
+	{
+	  if (trans_i->code_min <= (tre_cint_t)prev_c
+	      && trans_i->code_max >= (tre_cint_t)prev_c)
+	    {
+	      if (trans_i->assertions
+		  && (CHECK_ASSERTIONS(trans_i->assertions)
+		      || CHECK_CHAR_CLASSES(trans_i, tnfa, eflags)))
+		{
+		  continue;
+		}
+
+	      if (next_state == NULL)
+		{
+		  /* First matching transition. */
+		  next_state = trans_i->state;
+		  next_tags = trans_i->tags;
+		}
+	      else
+		{
+		  /* Second matching transition.  We may need to backtrack here
+		     to take this transition instead of the first one, so we
+		     push this transition in the backtracking stack so we can
+		     jump back here if needed. */
+		  BT_STACK_PUSH(pos, str_byte, 0, trans_i->state,
+				trans_i->state_id, next_c, tags, mbstate);
+		  {
+		    int *tmp;
+		    for (tmp = trans_i->tags; tmp && *tmp >= 0; tmp++)
+		      stack->item.tags[*tmp] = pos;
+		  }
+#if 0 /* XXX - it's important not to look at all transitions here to keep
+	 the stack small! */
+		  break;
+#endif
+		}
+	    }
+	}
+
+      if (next_state != NULL)
+	{
+	  /* Matching transitions were found.  Take the first one. */
+	  state = next_state;
+
+	  /* Update the tag values. */
+	  if (next_tags)
+	    while (*next_tags >= 0)
+	      tags[*next_tags++] = pos;
+	}
+      else
+	{
+	backtrack:
+	  /* A matching transition was not found.  Try to backtrack. */
+	  if (stack->prev)
+	    {
+	      if (stack->item.state->assertions & ASSERT_BACKREF)
+		{
+		  states_seen[stack->item.state_id] = 0;
+		}
+
+	      BT_STACK_POP();
+	    }
+	  else if (match_eo < 0)
+	    {
+	      /* Try starting from a later position in the input string. */
+	      /* Check for end of string. */
+	      if (next_c == L'\0')
+		    {
+		      break;
+		    }
+	      next_c = next_c_start;
+#ifdef TRE_MBSTATE
+	      mbstate = mbstate_start;
+#endif /* TRE_MBSTATE */
+	      str_byte = str_byte_start;
+	      goto retry;
+	    }
+	  else
+	    {
+	      break;
+	    }
+	}
+    }
+
+  ret = match_eo >= 0 ? REG_OK : REG_NOMATCH;
+  *match_end_ofs = match_eo;
+
+ error_exit:
+  tre_bt_mem_destroy(mem);
+#ifndef TRE_USE_ALLOCA
+  if (tags)
+    xfree(tags);
+  if (pmatch)
+    xfree(pmatch);
+  if (states_seen)
+    xfree(states_seen);
+#endif /* !TRE_USE_ALLOCA */
+
+  return ret;
+}
+
+/***********************************************************************
+ from regexec.c
+***********************************************************************/
+
+/* Fills the POSIX.2 regmatch_t array according to the TNFA tag and match
+   endpoint values. */
+static void
+tre_fill_pmatch(size_t nmatch, regmatch_t pmatch[], int cflags,
+		const tre_tnfa_t *tnfa, regoff_t *tags, regoff_t match_eo)
+{
+  tre_submatch_data_t *submatch_data;
+  unsigned int i, j;
+  int *parents;
+
+  i = 0;
+  if (match_eo >= 0 && !(cflags & REG_NOSUB))
+    {
+      /* Construct submatch offsets from the tags. */
+      submatch_data = tnfa->submatch_data;
+      while (i < tnfa->num_submatches && i < nmatch)
+	{
+	  if (submatch_data[i].so_tag == tnfa->end_tag)
+	    pmatch[i].rm_so = match_eo;
+	  else
+	    pmatch[i].rm_so = tags[submatch_data[i].so_tag];
+
+	  if (submatch_data[i].eo_tag == tnfa->end_tag)
+	    pmatch[i].rm_eo = match_eo;
+	  else
+	    pmatch[i].rm_eo = tags[submatch_data[i].eo_tag];
+
+	  /* If either of the endpoints were not used, this submatch
+	     was not part of the match. */
+	  if (pmatch[i].rm_so == -1 || pmatch[i].rm_eo == -1)
+	    pmatch[i].rm_so = pmatch[i].rm_eo = -1;
+
+	  i++;
+	}
+      /* Reset all submatches that are not within all of their parent
+	 submatches. */
+      i = 0;
+      while (i < tnfa->num_submatches && i < nmatch)
+	{
+	  if (pmatch[i].rm_eo == -1)
+	    assert(pmatch[i].rm_so == -1);
+	  assert(pmatch[i].rm_so <= pmatch[i].rm_eo);
+
+	  parents = submatch_data[i].parents;
+	  if (parents != NULL)
+	    for (j = 0; parents[j] >= 0; j++)
+	      {
+		if (pmatch[i].rm_so < pmatch[parents[j]].rm_so
+		    || pmatch[i].rm_eo > pmatch[parents[j]].rm_eo)
+		  pmatch[i].rm_so = pmatch[i].rm_eo = -1;
+	      }
+	  i++;
+	}
+    }
+
+  while (i < nmatch)
+    {
+      pmatch[i].rm_so = -1;
+      pmatch[i].rm_eo = -1;
+      i++;
+    }
+}
+
+
+/*
+  Wrapper functions for POSIX compatible regexp matching.
+*/
+
+int
+regexec(const regex_t *restrict preg, const char *restrict string,
+	  size_t nmatch, regmatch_t pmatch[restrict], int eflags)
+{
+  tre_tnfa_t *tnfa = (void *)preg->TRE_REGEX_T_FIELD;
+  reg_errcode_t status;
+  regoff_t *tags = NULL, eo;
+  if (tnfa->cflags & REG_NOSUB) nmatch = 0;
+  if (tnfa->num_tags > 0 && nmatch > 0)
+    {
+      tags = xmalloc(sizeof(*tags) * tnfa->num_tags);
+      if (tags == NULL)
+	return REG_ESPACE;
+    }
+
+  /* Dispatch to the appropriate matcher. */
+  if (tnfa->have_backrefs)
+    {
+      /* The regex has back references, use the backtracking matcher. */
+      status = tre_tnfa_run_backtrack(tnfa, string, tags, eflags, &eo);
+    }
+  else
+    {
+      /* Exact matching, no back references, use the parallel matcher. */
+      status = tre_tnfa_run_parallel(tnfa, string, tags, eflags, &eo);
+    }
+
+  if (status == REG_OK)
+    /* A match was found, so fill the submatch registers. */
+    tre_fill_pmatch(nmatch, pmatch, tnfa->cflags, tnfa, tags, eo);
+  if (tags)
+    xfree(tags);
+  return status;
+}
diff --git a/vendor/tre-regex/tre-mem.c b/vendor/tre-regex/tre-mem.c
new file mode 100644
index 0000000..86f809d
--- /dev/null
+++ b/vendor/tre-regex/tre-mem.c
@@ -0,0 +1,158 @@
+/*
+  tre-mem.c - TRE memory allocator
+
+  Copyright (c) 2001-2009 Ville Laurikari <vl@iki.fi>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions
+  are met:
+
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS
+  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+  A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
+  HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+*/
+
+/*
+  This memory allocator is for allocating small memory blocks efficiently
+  in terms of memory overhead and execution speed.  The allocated blocks
+  cannot be freed individually, only all at once.  There can be multiple
+  allocators, though.
+*/
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "tre.h"
+
+/*
+  This memory allocator is for allocating small memory blocks efficiently
+  in terms of memory overhead and execution speed.  The allocated blocks
+  cannot be freed individually, only all at once.  There can be multiple
+  allocators, though.
+*/
+
+/* Returns a new memory allocator or NULL if out of memory. */
+tre_mem_t
+tre_mem_new_impl(int provided, void *provided_block)
+{
+  tre_mem_t mem;
+  if (provided)
+    {
+      mem = provided_block;
+      memset(mem, 0, sizeof(*mem));
+    }
+  else
+    mem = xcalloc(1, sizeof(*mem));
+  if (mem == NULL)
+    return NULL;
+  return mem;
+}
+
+
+/* Frees the memory allocator and all memory allocated with it. */
+void
+tre_mem_destroy(tre_mem_t mem)
+{
+  tre_list_t *tmp, *l = mem->blocks;
+
+  while (l != NULL)
+    {
+      xfree(l->data);
+      tmp = l->next;
+      xfree(l);
+      l = tmp;
+    }
+  xfree(mem);
+}
+
+
+/* Allocates a block of `size' bytes from `mem'.  Returns a pointer to the
+   allocated block or NULL if an underlying malloc() failed. */
+void *
+tre_mem_alloc_impl(tre_mem_t mem, int provided, void *provided_block,
+		   int zero, size_t size)
+{
+  void *ptr;
+
+  if (mem->failed)
+    {
+      return NULL;
+    }
+
+  if (mem->n < size)
+    {
+      /* We need more memory than is available in the current block.
+	 Allocate a new block. */
+      tre_list_t *l;
+      if (provided)
+	{
+	  if (provided_block == NULL)
+	    {
+	      mem->failed = 1;
+	      return NULL;
+	    }
+	  mem->ptr = provided_block;
+	  mem->n = TRE_MEM_BLOCK_SIZE;
+	}
+      else
+	{
+	  int block_size;
+	  if (size * 8 > TRE_MEM_BLOCK_SIZE)
+	    block_size = size * 8;
+	  else
+	    block_size = TRE_MEM_BLOCK_SIZE;
+	  l = xmalloc(sizeof(*l));
+	  if (l == NULL)
+	    {
+	      mem->failed = 1;
+	      return NULL;
+	    }
+	  l->data = xmalloc(block_size);
+	  if (l->data == NULL)
+	    {
+	      xfree(l);
+	      mem->failed = 1;
+	      return NULL;
+	    }
+	  l->next = NULL;
+	  if (mem->current != NULL)
+	    mem->current->next = l;
+	  if (mem->blocks == NULL)
+	    mem->blocks = l;
+	  mem->current = l;
+	  mem->ptr = l->data;
+	  mem->n = block_size;
+	}
+    }
+
+  /* Make sure the next pointer will be aligned. */
+  size += ALIGN(mem->ptr + size, long);
+
+  /* Allocate from current block. */
+  ptr = mem->ptr;
+  mem->ptr += size;
+  mem->n -= size;
+
+  /* Set to zero if needed. */
+  if (zero)
+    memset(ptr, 0, size);
+
+  return ptr;
+}
diff --git a/vendor/tre-regex/tre.h b/vendor/tre-regex/tre.h
new file mode 100644
index 0000000..923e2d5
--- /dev/null
+++ b/vendor/tre-regex/tre.h
@@ -0,0 +1,267 @@
+/*
+  tre-internal.h - TRE internal definitions
+
+  Copyright (c) 2001-2009 Ville Laurikari <vl@iki.fi>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions
+  are met:
+
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS
+  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+  A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
+  HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+*/
+
+#include "regex.h"
+#include <stdint.h>
+#include <wchar.h>
+#include <wctype.h>
+
+#define hidden
+
+#undef  TRE_MBSTATE
+
+#ifndef NDEBUG
+#define NDEBUG
+#endif
+
+#ifndef CHARCLASS_NAME_MAX
+#define CHARCLASS_NAME_MAX 14
+#endif
+#ifndef RE_DUP_MAX
+#define RE_DUP_MAX 255
+#endif
+
+#define TRE_REGEX_T_FIELD __opaque
+typedef int reg_errcode_t;
+
+typedef int tre_char_t;
+
+#define DPRINT(msg) do { } while(0)
+
+#define elementsof(x)	( sizeof(x) / sizeof(x[0]) )
+
+/* wchar_t is 16 bits on Windows: decode UTF-8 to code points ourselves.
+   Returns the sequence length, 0 at NUL, -1 on invalid input. */
+static inline int tre_mbtowc(tre_char_t *pwc, const char *s, size_t n)
+{
+	const unsigned char *p = (const unsigned char *)s;
+	int c, len, i;
+	if (n == 0) return -1;
+	c = p[0];
+	if (c < 0x80) { *pwc = c; return c ? 1 : 0; }
+	if (c < 0xC2) return -1;
+	if (c < 0xE0) { len = 2; c &= 0x1F; }
+	else if (c < 0xF0) { len = 3; c &= 0x0F; }
+	else if (c < 0xF5) { len = 4; c &= 0x07; }
+	else return -1;
+	if ((size_t)len > n) return -1;
+	for (i = 1; i < len; i++) {
+		if ((p[i] & 0xC0) != 0x80) return -1;
+		c = (c << 6) | (p[i] & 0x3F);
+	}
+	if ((len == 3 && c < 0x800) || (len == 4 && (c < 0x10000 || c > 0x10FFFF))
+	    || (c >= 0xD800 && c <= 0xDFFF)) return -1;
+	*pwc = c;
+	return len;
+}
+#define tre_mbrtowc(pwc, s, n, ps) (tre_mbtowc((pwc), (s), (n)))
+
+/* Wide characters. */
+typedef int tre_cint_t;
+#define TRE_CHAR_MAX 0x10ffff
+
+#define tre_isalnum(c) ((c) <= 0xFFFF ? iswalnum((wint_t)(c)) : 1)
+#define tre_isalpha(c) ((c) <= 0xFFFF ? iswalpha((wint_t)(c)) : 1)
+#define tre_isblank(c) ((c) <= 0xFFFF ? iswblank((wint_t)(c)) : 0)
+#define tre_iscntrl(c) ((c) <= 0xFFFF ? iswcntrl((wint_t)(c)) : 0)
+#define tre_isdigit(c) ((c) <= 0xFFFF ? iswdigit((wint_t)(c)) : 0)
+#define tre_isgraph(c) ((c) <= 0xFFFF ? iswgraph((wint_t)(c)) : 1)
+#define tre_islower(c) ((c) <= 0xFFFF ? iswlower((wint_t)(c)) : 0)
+#define tre_isprint(c) ((c) <= 0xFFFF ? iswprint((wint_t)(c)) : 1)
+#define tre_ispunct(c) ((c) <= 0xFFFF ? iswpunct((wint_t)(c)) : 0)
+#define tre_isspace(c) ((c) <= 0xFFFF ? iswspace((wint_t)(c)) : 0)
+#define tre_isupper(c) ((c) <= 0xFFFF ? iswupper((wint_t)(c)) : 0)
+#define tre_isxdigit(c) ((c) <= 0xFFFF ? iswxdigit((wint_t)(c)) : 0)
+
+#define tre_tolower(c) ((c) <= 0xFFFF ? (int)towlower((wint_t)(c)) : (c))
+#define tre_toupper(c) ((c) <= 0xFFFF ? (int)towupper((wint_t)(c)) : (c))
+#define tre_strlen  wcslen
+
+/* Use system provided iswctype() and wctype(). */
+typedef wctype_t tre_ctype_t;
+#define tre_isctype(c, t) ((c) <= 0xFFFF ? iswctype((wint_t)(c), (t)) : 0)
+#define tre_ctype   wctype
+
+/* Returns number of bytes to add to (char *)ptr to make it
+   properly aligned for the type. */
+#define ALIGN(ptr, type) \
+  ((((uintptr_t)ptr) % sizeof(type)) \
+   ? (sizeof(type) - (((uintptr_t)ptr) % sizeof(type))) \
+   : 0)
+
+#undef MAX
+#undef MIN
+#define MAX(a, b) (((a) >= (b)) ? (a) : (b))
+#define MIN(a, b) (((a) <= (b)) ? (a) : (b))
+
+/* TNFA transition type. A TNFA state is an array of transitions,
+   the terminator is a transition with NULL `state'. */
+typedef struct tnfa_transition tre_tnfa_transition_t;
+
+struct tnfa_transition {
+  /* Range of accepted characters. */
+  tre_cint_t code_min;
+  tre_cint_t code_max;
+  /* Pointer to the destination state. */
+  tre_tnfa_transition_t *state;
+  /* ID number of the destination state. */
+  int state_id;
+  /* -1 terminated array of tags (or NULL). */
+  int *tags;
+  /* Assertion bitmap. */
+  int assertions;
+  /* Assertion parameters. */
+  union {
+    /* Character class assertion. */
+    tre_ctype_t class;
+    /* Back reference assertion. */
+    int backref;
+  } u;
+  /* Negative character class assertions. */
+  tre_ctype_t *neg_classes;
+};
+
+
+/* Assertions. */
+#define ASSERT_AT_BOL		  1   /* Beginning of line. */
+#define ASSERT_AT_EOL		  2   /* End of line. */
+#define ASSERT_CHAR_CLASS	  4   /* Character class in `class'. */
+#define ASSERT_CHAR_CLASS_NEG	  8   /* Character classes in `neg_classes'. */
+#define ASSERT_AT_BOW		 16   /* Beginning of word. */
+#define ASSERT_AT_EOW		 32   /* End of word. */
+#define ASSERT_AT_WB		 64   /* Word boundary. */
+#define ASSERT_AT_WB_NEG	128   /* Not a word boundary. */
+#define ASSERT_BACKREF		256   /* A back reference in `backref'. */
+#define ASSERT_LAST		256
+
+/* Tag directions. */
+typedef enum {
+  TRE_TAG_MINIMIZE = 0,
+  TRE_TAG_MAXIMIZE = 1
+} tre_tag_direction_t;
+
+/* Instructions to compute submatch register values from tag values
+   after a successful match.  */
+struct tre_submatch_data {
+  /* Tag that gives the value for rm_so (submatch start offset). */
+  int so_tag;
+  /* Tag that gives the value for rm_eo (submatch end offset). */
+  int eo_tag;
+  /* List of submatches this submatch is contained in. */
+  int *parents;
+};
+
+typedef struct tre_submatch_data tre_submatch_data_t;
+
+
+/* TNFA definition. */
+typedef struct tnfa tre_tnfa_t;
+
+struct tnfa {
+  tre_tnfa_transition_t *transitions;
+  unsigned int num_transitions;
+  tre_tnfa_transition_t *initial;
+  tre_tnfa_transition_t *final;
+  tre_submatch_data_t *submatch_data;
+  char *firstpos_chars;
+  int first_char;
+  unsigned int num_submatches;
+  tre_tag_direction_t *tag_directions;
+  int *minimal_tags;
+  int num_tags;
+  int num_minimals;
+  int end_tag;
+  int num_states;
+  int cflags;
+  int have_backrefs;
+  int have_approx;
+};
+
+/* from tre-mem.h: */
+
+#define TRE_MEM_BLOCK_SIZE 1024
+
+typedef struct tre_list {
+  void *data;
+  struct tre_list *next;
+} tre_list_t;
+
+typedef struct tre_mem_struct {
+  tre_list_t *blocks;
+  tre_list_t *current;
+  char *ptr;
+  size_t n;
+  int failed;
+  void **provided;
+} *tre_mem_t;
+
+#define tre_mem_new_impl   __tre_mem_new_impl
+#define tre_mem_alloc_impl __tre_mem_alloc_impl
+#define tre_mem_destroy    __tre_mem_destroy
+
+hidden tre_mem_t tre_mem_new_impl(int provided, void *provided_block);
+hidden void *tre_mem_alloc_impl(tre_mem_t mem, int provided, void *provided_block,
+                                int zero, size_t size);
+
+/* Returns a new memory allocator or NULL if out of memory. */
+#define tre_mem_new()  tre_mem_new_impl(0, NULL)
+
+/* Allocates a block of `size' bytes from `mem'.  Returns a pointer to the
+   allocated block or NULL if an underlying malloc() failed. */
+#define tre_mem_alloc(mem, size) tre_mem_alloc_impl(mem, 0, NULL, 0, size)
+
+/* Allocates a block of `size' bytes from `mem'.  Returns a pointer to the
+   allocated block or NULL if an underlying malloc() failed.  The memory
+   is set to zero. */
+#define tre_mem_calloc(mem, size) tre_mem_alloc_impl(mem, 0, NULL, 1, size)
+
+#ifdef TRE_USE_ALLOCA
+/* alloca() versions.  Like above, but memory is allocated with alloca()
+   instead of malloc(). */
+
+#define tre_mem_newa() \
+  tre_mem_new_impl(1, alloca(sizeof(struct tre_mem_struct)))
+
+#define tre_mem_alloca(mem, size)					      \
+  ((mem)->n >= (size)							      \
+   ? tre_mem_alloc_impl((mem), 1, NULL, 0, (size))			      \
+   : tre_mem_alloc_impl((mem), 1, alloca(TRE_MEM_BLOCK_SIZE), 0, (size)))
+#endif /* TRE_USE_ALLOCA */
+
+
+/* Frees the memory allocator and all memory allocated with it. */
+hidden void tre_mem_destroy(tre_mem_t mem);
+
+#define xmalloc malloc
+#define xcalloc calloc
+#define xfree free
+#define xrealloc realloc
+