#ifndef CST_SANDBOX_H
#define CST_SANDBOX_H

/*
 * OS sandbox for run_shell: reads and exec stay allowed everywhere, writes
 * are limited to the workspace, the temp dir, /dev/null and /dev/tty, and
 * the network is cut where the OS can do it.
 *   Linux   Landlock (network needs ABI 4, kernel 6.7+)
 *   Linux   seccomp user-notify when Landlock is missing (Android/Termux,
 *           older kernels): a supervisor thread checks the path of every
 *           write-type syscall and IPv4/IPv6 sockets are refused. Guards
 *           against mistakes, not hostile code (the path is checked before
 *           the kernel reads it again).
 *   macOS   sandbox_init (Seatbelt profile)
 *   other   none: callers fall back to rule-based approval
 */

#include "os_compat.h"

#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif

typedef enum {
  CST_SANDBOX_NONE = 0,
  CST_SANDBOX_LANDLOCK,
  CST_SANDBOX_SEATBELT,
  CST_SANDBOX_SECCOMP
} 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. */
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" */
const char *cst_sandbox_name(int kind);
/* Landlock ABI version (0 when unavailable); ≥4 also blocks TCP. */
int cst_sandbox_landlock_abi(void);

typedef struct {
  int kind;
  int ruleset_fd; /* Landlock, built in the parent */
  char *profile;  /* Seatbelt */
  void *sc;       /* seccomp: filter program and supervisor thread */
} cst_sandbox_plan_t;

/* Parent side: build the policy. Returns 0, or -1 (plan->kind = NONE). */
int cst_sandbox_prepare(const char *workspace, const char *tmpdir,
                        cst_sandbox_plan_t *plan);
/* Child side, after fork and before exec (os_run_capture_ex hook):
 * async-signal-safe. Returns 0 when confined. */
int cst_sandbox_enter(void *plan);
void cst_sandbox_release(cst_sandbox_plan_t *plan);

/* `sh -c cmd` confined to workspace (+ temp dir). Fails closed: if the
 * policy cannot be applied the command does not run (exit 126). */
int cst_sandbox_run_shell(const char *workspace, const char *cmd,
                          size_t max_out, os_run_result_t *r);

/* Output of a failed sandboxed run that looks like the sandbox got in the
 * way (EACCES / EPERM / EROFS / blocked network). */
int cst_sandbox_blocked(const char *out, size_t n, int exit_code);

#ifdef __cplusplus
}
#endif

#endif