static char _clar_path[4096];

static int

is_valid_tmp_path(const char *path)

{

	STAT_T st;

	if (stat(path, &st) != 0)

		return 0;

	if (!S_ISDIR(st.st_mode))

		return 0;

	return (access(path, W_OK) == 0);

}

static int

find_tmp_path(char *buffer, size_t length)

{

#ifndef _WIN32

	static const size_t var_count = 5;

	static const char *env_vars[] = {

		"CLAR_TMP", "TMPDIR", "TMP", "TEMP", "USERPROFILE"

 	};

 	size_t i;

	for (i = 0; i < var_count; ++i) {

		const char *env = getenv(env_vars[i]);

		if (!env)

			continue;

		if (is_valid_tmp_path(env)) {

			strncpy(buffer, env, length);

			return 0;

		}

	}

	/* If the environment doesn't say anything, try to use /tmp */

	if (is_valid_tmp_path("/tmp")) {

		strncpy(buffer, "/tmp", length);

		return 0;

	}

#else

	DWORD env_len = GetEnvironmentVariable("CLAR_TMP", buffer, (DWORD)length);

	if (env_len > 0 && env_len < (DWORD)length)

		return 0;

	if (GetTempPath((DWORD)length, buffer))

		return 0;

#endif

	/* This system doesn't like us, try to use the current directory */

	if (is_valid_tmp_path(".")) {

		strncpy(buffer, ".", length);

		return 0;

	}

	return -1;

}

static void clar_unsandbox(void)

{

	if (_clar_path[0] == '\0')

		return;

	cl_must_pass(chdir(".."));

	fs_rm(_clar_path);

}

static int build_sandbox_path(void)

{

#ifdef CLAR_TMPDIR

	const char path_tail[] = CLAR_TMPDIR "_XXXXXX";

#else

	const char path_tail[] = "clar_tmp_XXXXXX";

#endif

	size_t len;

	if (find_tmp_path(_clar_path, sizeof(_clar_path)) < 0)

		return -1;

	len = strlen(_clar_path);

#ifdef _WIN32

	{ /* normalize path to POSIX forward slashes */

		size_t i;

		for (i = 0; i < len; ++i) {

			if (_clar_path[i] == '\\')

				_clar_path[i] = '/';

		}

	}

#endif

	if (_clar_path[len - 1] != '/') {

		_clar_path[len++] = '/';

	}

	strncpy(_clar_path + len, path_tail, sizeof(_clar_path) - len);

#if defined(__MINGW32__)

	if (_mktemp(_clar_path) == NULL)

		return -1;

	if (mkdir(_clar_path, 0700) != 0)

		return -1;

#elif defined(_WIN32)

	if (_mktemp_s(_clar_path, sizeof(_clar_path)) != 0)

		return -1;

	if (mkdir(_clar_path, 0700) != 0)

		return -1;

#else

	if (mkdtemp(_clar_path) == NULL)

		return -1;

#endif

	return 0;

}

static int clar_sandbox(void)

{

	if (_clar_path[0] == '\0' && build_sandbox_path() < 0)

		return -1;

	if (chdir(_clar_path) != 0)

		return -1;

	return 0;

}

const char *clar_sandbox_path(void)

{

	return _clar_path;

}