Hermit/src/os_compat.c

#ifndef _DEFAULT_SOURCE
#define _DEFAULT_SOURCE
#endif
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

#ifdef __APPLE__
#include <mach-o/dyld.h>
#include <stdint.h>
#endif
#include "os_compat.h"

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef _WIN32
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#include <direct.h>
#include <fcntl.h>
#include <io.h>
#include <process.h>
#include <windows.h>
#else
#include <fcntl.h>
#include <poll.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#endif

void os_run_result_free(os_run_result_t *r) {
  if (!r)
    return;
  free(r->out);
  r->out = NULL;
  r->out_len = 0;
}

int os_path_is_abs(const char *p) {
  if (!p || !p[0])
    return 0;
#ifdef _WIN32
  if (p[0] == '/' || p[0] == '\\')
    return 1;
  if (((p[0] >= 'A' && p[0] <= 'Z') || (p[0] >= 'a' && p[0] <= 'z')) &&
      p[1] == ':' && (p[2] == '/' || p[2] == '\\' || p[2] == '\0'))
    return 1;
  return 0;
#else
  return p[0] == '/';
#endif
}

void os_path_norm_slashes(char *p) {
  if (!p)
    return;
  for (; *p; p++) {
    if (*p == '\\')
      *p = '/';
  }
}

int os_path_join(char *out, size_t out_sz, const char *a, const char *b) {
  if (!out || out_sz < 2 || !a)
    return -1;
  if (!b || !b[0]) {
    snprintf(out, out_sz, "%s", a);
    return 0;
  }
  if (os_path_is_abs(b)) {
    snprintf(out, out_sz, "%s", b);
    return 0;
  }
  size_t al = strlen(a);
  while (al > 0 && (a[al - 1] == '/' || a[al - 1] == '\\'))
    al--;
#ifdef _WIN32
  int n = snprintf(out, out_sz, "%.*s\\%s", (int)al, a, b);
#else
  int n = snprintf(out, out_sz, "%.*s/%s", (int)al, a, b);
#endif
  if (n < 0 || (size_t)n >= out_sz)
    return -1;
  return 0;
}

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;
  if (strlen(r) + 1 > out_sz) {
    free(r);
    return -1;
  }
  memcpy(out, r, strlen(r) + 1);
  free(r);
  return 0;
#endif
}

int os_path_under(const char *root, const char *path) {
  if (!root || !path)
    return 0;
  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
}

int os_mkdir(const char *path, int mode) {
  if (!path)
    return -1;
#ifdef _WIN32
  (void)mode;
  if (_mkdir(path) != 0 && errno != EEXIST)
    return -1;
  return 0;
#else
  if (mkdir(path, (mode_t)mode) != 0 && errno != EEXIST)
    return -1;
  return 0;
#endif
}

int os_mkdir_p(const char *path, int mode) {
  if (!path || !path[0])
    return -1;
  char tmp[OS_PATH_MAX];
  snprintf(tmp, sizeof(tmp), "%s", path);
  for (char *p = tmp + 1; *p; p++) {
    if (*p == '/' || *p == '\\') {
      char c = *p;
      *p = 0;
      os_mkdir(tmp, mode);
      *p = c;
    }
  }
  return os_mkdir(tmp, mode);
}

int os_config_dir(char *out, size_t out_sz) {
  if (!out || out_sz < 8)
    return -1;
#ifdef _WIN32
  const char *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);
#else
  const char *xdg = getenv("XDG_CONFIG_HOME");
  const char *home = getenv("HOME");
  int n;
  if (xdg && xdg[0] == '/')
    n = snprintf(out, out_sz, "%s/cst-agent", xdg);
  else if (home && home[0])
    n = snprintf(out, out_sz, "%s/.config/cst-agent", home);
  else
    return -1;
#endif
  if (n < 0 || (size_t)n >= out_sz)
    return -1;
  return 0;
}

int os_temp_dir(char *out, size_t out_sz) {
  if (!out || out_sz < 2)
    return -1;
#ifdef _WIN32
  DWORD n = GetTempPathA((DWORD)out_sz, out);
  if (n == 0 || n >= out_sz)
    return -1;
  os_path_norm_slashes(out);
  size_t L = strlen(out);
  while (L > 0 && out[L - 1] == '/')
    out[--L] = 0;
  return 0;
#else
  const char *t = getenv("TMPDIR");
  if (!t || !t[0])
    t = "/tmp";
  snprintf(out, out_sz, "%s", t);
  return 0;
#endif
}

int os_mkstemp(char *out, size_t out_sz, const char *prefix) {
  if (!out || out_sz < 16)
    return -1;
  char dir[OS_PATH_MAX];
  if (os_temp_dir(dir, sizeof(dir)) != 0)
    return -1;
  if (!prefix)
    prefix = "cst";
#ifdef _WIN32
  char name[MAX_PATH];
  if (GetTempFileNameA(dir, prefix, 0, name) == 0)
    return -1;
  os_path_norm_slashes(name);
  if (strlen(name) + 1 > out_sz)
    return -1;
  memcpy(out, name, strlen(name) + 1);
  int fd = _open(out, _O_RDWR | _O_BINARY);
  return fd;
#else
  int n = snprintf(out, out_sz, "%s/%s-XXXXXX", dir, prefix);
  if (n < 0 || (size_t)n >= out_sz)
    return -1;
  int fd = mkstemp(out);
  return fd;
#endif
}

/* Optional: main() may set this for Termux / argv0 fallback when
 * /proc/self/exe is unavailable. */
static char g_argv0_dir[OS_PATH_MAX];

void os_set_prog_path(const char *argv0) {
  g_argv0_dir[0] = 0;
  if (!argv0 || !argv0[0])
    return;
  char buf[OS_PATH_MAX];
  snprintf(buf, sizeof(buf), "%s", argv0);
  os_path_norm_slashes(buf);
  char *slash = strrchr(buf, '/');
  if (!slash)
    return;
  *slash = 0;
  /* Relative "./foo" → keep as-is; caller may pass absolute. */
  snprintf(g_argv0_dir, sizeof(g_argv0_dir), "%s", buf);
}

int os_exe_dir(char *out, size_t out_sz) {
  if (!out || out_sz < 2)
    return -1;
  const char *env = getenv("CST_EXE_DIR");
  if (env && env[0]) {
    snprintf(out, out_sz, "%s", env);
    return 0;
  }
#ifdef _WIN32
  char buf[OS_PATH_MAX];
  DWORD n = GetModuleFileNameA(NULL, buf, (DWORD)sizeof(buf));
  if (n == 0 || n >= sizeof(buf))
    return -1;
  os_path_norm_slashes(buf);
  char *slash = strrchr(buf, '/');
  if (!slash)
    return -1;
  *slash = 0;
  if (strlen(buf) + 1 > out_sz)
    return -1;
  memcpy(out, buf, strlen(buf) + 1);
  return 0;
#else
  char buf[OS_PATH_MAX];
#ifdef __APPLE__
  uint32_t asz = (uint32_t)sizeof(buf);
  ssize_t n = _NSGetExecutablePath(buf, &asz) == 0 ? (ssize_t)strlen(buf) : -1;
#else
  ssize_t n = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
#endif
  if (n >= 0) {
    buf[n] = 0;
    char *slash = strrchr(buf, '/');
    if (slash) {
      *slash = 0;
      if (strlen(buf) + 1 <= out_sz) {
        memcpy(out, buf, strlen(buf) + 1);
        return 0;
      }
    }
  }
  /* Termux / restricted Android: fall back to argv0 dir. */
  if (g_argv0_dir[0]) {
    snprintf(out, out_sz, "%s", g_argv0_dir);
    return 0;
  }
  return -1;
#endif
}

static int file_exists(const char *p) {
#ifdef _WIN32
  DWORD a = GetFileAttributesA(p);
  return a != INVALID_FILE_ATTRIBUTES && !(a & FILE_ATTRIBUTE_DIRECTORY);
#else
  return access(p, X_OK) == 0 || access(p, F_OK) == 0;
#endif
}

int os_resolve_shell(char *out, size_t out_sz) {
  if (!out || out_sz < 2)
    return -1;
  const char *env = getenv("CST_SHELL");
  if (env && env[0]) {
    snprintf(out, out_sz, "%s", env);
    return 0;
  }
  char dir[OS_PATH_MAX];
  if (os_exe_dir(dir, sizeof(dir)) == 0) {
#ifdef _WIN32
    char cand[OS_PATH_MAX];
    if (os_path_join(cand, sizeof(cand), dir, "busybox.exe") == 0 &&
        file_exists(cand)) {
      snprintf(out, out_sz, "%s", cand);
      return 0;
    }
#else
    char cand[OS_PATH_MAX];
    if (os_path_join(cand, sizeof(cand), dir, "busybox") == 0 &&
        file_exists(cand)) {
      snprintf(out, out_sz, "%s", cand);
      return 0;
    }
#endif
  }
#ifdef _WIN32
  snprintf(out, out_sz, "%s", "busybox.exe");
  return 0;
#else
  /* Termux: $PREFIX/bin/sh */
  {
    const char *prefix = getenv("PREFIX");
    if (prefix && prefix[0]) {
      char cand[OS_PATH_MAX];
      if (os_path_join(cand, sizeof(cand), prefix, "bin/sh") == 0 &&
          file_exists(cand)) {
        snprintf(out, out_sz, "%s", cand);
        return 0;
      }
    }
  }
  if (file_exists("/bin/sh")) {
    snprintf(out, out_sz, "%s", "/bin/sh");
    return 0;
  }
  if (file_exists("/system/bin/sh")) {
    snprintf(out, out_sz, "%s", "/system/bin/sh");
    return 0;
  }
  snprintf(out, out_sz, "%s", "sh");
  return 0;
#endif
}

static volatile int *g_run_cancel;
static int g_run_timeout_s;

void os_set_cancel_flag(volatile int *flag) { g_run_cancel = flag; }

void os_set_run_timeout(int seconds) { g_run_timeout_s = seconds; }

static int run_timeout_s(void) {
  if (g_run_timeout_s > 0)
    return g_run_timeout_s;
  const char *e = getenv("CST_SHELL_TIMEOUT");
  if (e && atoi(e) > 0)
    return atoi(e);
  return 120;
}

double os_now_ms(void) {
#ifdef _WIN32
  static LARGE_INTEGER freq;
  LARGE_INTEGER now;
  if (!freq.QuadPart)
    QueryPerformanceFrequency(&freq);
  QueryPerformanceCounter(&now);
  return (double)now.QuadPart * 1000.0 / (double)freq.QuadPart;
#else
  struct timespec ts;
  clock_gettime(CLOCK_MONOTONIC, &ts);
  return (double)ts.tv_sec * 1000.0 + (double)ts.tv_nsec / 1e6;
#endif
}

/* 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) {
  if (*len >= max_out) {
    *truncated = 1;
    return 0;
  }
  if (*len + n > max_out) {
    n = max_out - *len;
    *truncated = 1;
  }
  if (*len + n + 1 > *cap) {
    size_t nc = *cap ? *cap * 2 : 4096;
    while (nc < *len + n + 1)
      nc *= 2;
    char *nb = realloc(*buf, nc);
    if (!nb)
      return -1;
    *buf = nb;
    *cap = nc;
  }
  memcpy(*buf + *len, data, n);
  *len += n;
  (*buf)[*len] = 0;
  return 0;
}

static void 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);
    if (!nb)
      return;
    *buf = nb;
    *cap = *len + n + 1;
  }
  memcpy(*buf + *len, note, n + 1);
  *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
int os_run_capture(const char *cwd, const char *const argv[], size_t max_out,
                   os_run_result_t *r) {
  return os_run_capture_ex(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) {
  if (!argv || !argv[0] || !r)
    return -1;
  if (max_out == 0)
    max_out = 512 * 1024;
  memset(r, 0, sizeof(*r));

  int pipefd[2];
  if (pipe(pipefd) != 0)
    return -1;
  pid_t pid = fork();
  if (pid < 0) {
    close(pipefd[0]);
    close(pipefd[1]);
    return -1;
  }
  if (pid == 0) {
    setpgid(0, 0);
    close(pipefd[0]);
    int devnull = open("/dev/null", O_RDONLY);
    if (devnull >= 0) {
      dup2(devnull, STDIN_FILENO);
      close(devnull);
    }
    dup2(pipefd[1], STDOUT_FILENO);
    dup2(pipefd[1], STDERR_FILENO);
    close(pipefd[1]);
    if (cwd && cwd[0] && chdir(cwd) != 0)
      _exit(127);
    if (child_hook && child_hook(ud) != 0) {
      static const char msg[] = "[cst: sandbox setup failed; command not "
                                "run]\n";
      ssize_t w = write(STDERR_FILENO, msg, sizeof(msg) - 1);
      (void)w;
      _exit(126);
    }
    execvp(argv[0], (char *const *)argv);
    _exit(127);
  }
  setpgid(pid, pid); /* also in parent: avoid racing the child */
  close(pipefd[1]);
  size_t cap = 4096, len = 0;
  char *buf = malloc(cap);
  if (!buf) {
    close(pipefd[0]);
    kill(-pid, SIGKILL);
    waitpid(pid, NULL, 0);
    return -1;
  }
  buf[0] = 0;
  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;
  for (;;) {
    struct pollfd pfd = {pipefd[0], POLLIN, 0};
    int pr = poll(&pfd, 1, 100);
    if (pr < 0 && errno != EINTR)
      break;
    if (pr > 0) {
      char tmp[4096];
      ssize_t n = read(pipefd[0], tmp, sizeof(tmp));
      if (n == 0)
        break; /* every writer closed */
      if (n > 0)
        cap_append(&buf, &len, &cap, max_out, tmp, (size_t)n, &truncated);
      else if (errno != EINTR && errno != EAGAIN)
        break;
    }
    double now = os_now_ms();
    if (!reaped && waitpid(pid, &status, WNOHANG) == pid) {
      reaped = 1;
      reaped_at = now;
    }
    /* The shell exited but a background child still holds the pipe
     * (`server &`): give it a moment, then end the group. */
    if (reaped && !killed && !bg_killed && now - reaped_at > 1000) {
      kill(-pid, SIGKILL);
      bg_killed = 1;
      killed_at = now;
    }
    /* Checked on every pass, so a chatty command still stops promptly. */
    if (!reaped && !killed &&
        ((g_run_cancel && *g_run_cancel) || now > deadline)) {
      killed = (g_run_cancel && *g_run_cancel) ? 2 : 1;
      killed_at = now;
      kill(-pid, SIGTERM);
    }
    if (killed && !reaped && now - killed_at > 1000)
      kill(-pid, SIGKILL);
    /* a writer that left the process group can keep the pipe open */
    if ((killed || bg_killed) && now - killed_at > 3000)
      break;
  }
  close(pipefd[0]);
  if (pid > 0 && !reaped) {
    if (killed)
      kill(-pid, SIGKILL);
    waitpid(pid, &status, 0);
  }
  if (truncated)
    cap_note(&buf, &len, &cap, "\n...(output truncated)\n");
  if (bg_killed)
    cap_note(&buf, &len, &cap,
             "\n[cst: background processes left running were stopped]\n");
  r->out = buf;
  r->out_len = len;
  r->exit_code = WIFEXITED(status) ? WEXITSTATUS(status) : 1;
  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);
    r->exit_code = 124;
  } else if (killed == 2) {
    cap_note(&r->out, &r->out_len, &cap, "\n[cst: cancelled]\n");
    r->exit_code = 130;
  }
  return 0;
}
#endif

int os_run_shell_c(const char *cwd, const char *cmd, size_t max_out,
                   os_run_result_t *r) {
  return os_run_shell_ex(cwd, cmd, max_out, r, NULL, NULL);
}

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)
    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);
  }
}

void os_localtime(const time_t *t, struct tm *out) {
  if (!t || !out)
    return;
#ifdef _WIN32
  localtime_s(out, t);
#else
  localtime_r(t, out);
#endif
}

int os_getpid(void) {
#ifdef _WIN32
  return (int)GetCurrentProcessId();
#else
  return (int)getpid();
#endif
}

int os_chmod_private(const char *path) {
  if (!path)
    return -1;
#ifdef _WIN32
  (void)path;
  return 0;
#else
  return chmod(path, 0600);
#endif
}