Function cbm_mkdtemp

src/foundation/compat.c:117–204

}

char *cbm_mkdtemp(char *tmpl) {
    /* Per-call storage is required: daemon sessions invoke mkdtemp concurrently.
     * A process-global buffer lets one request overwrite another request's path
     * between expansion, creation, and the copy back to its caller. */
    char buf[CBM_SZ_512];
    int written;
    if (strncmp(tmpl, "/tmp/", 5) == 0) {
        const char *tmp = getenv("TEMP");
        if (!tmp)
            tmp = getenv("TMP");
        if (!tmp)
            tmp = ".";
        written = snprintf(buf, sizeof(buf), "%s\\%s", tmp, tmpl + 5);
    } else {
        written = snprintf(buf, sizeof(buf), "%s", tmpl);
    }
    if (written < 0 || (size_t)written >= sizeof(buf)) {
        errno = ENAMETOOLONG;
        return NULL;
    }

    size_t length = strlen(buf);
    if (length < 6 || strcmp(buf + length - 6, "XXXXXX") != 0) {
        errno = EINVAL;
        return NULL;
    }

    static const char alphabet[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
    bool created = false;
    for (int attempt = 0; attempt < 128; attempt++) {
        unsigned char random_suffix[6];
        if (!cbm_secure_random(random_suffix, sizeof(random_suffix))) {
            errno = EIO;
            return NULL;
        }
        for (size_t index = 0; index < sizeof(random_suffix); index++) {
            buf[length - sizeof(random_suffix) + index] =
                alphabet[random_suffix[index] % (sizeof(alphabet) - 1)];
        }

        if (win_mkdtemp_private_create(buf)) {
            created = true;
            break;
        }

        /* Keep the existing compatibility fallback when an explicit private
         * descriptor is unavailable. A name collision is retried; any other
         * filesystem refusal is returned to the caller immediately. */
        DWORD create_error = GetLastError();
        wchar_t *wide_directory = cbm_utf8_to_wide(buf);
        errno = 0;
        int mkdir_result = wide_directory ? _wmkdir(wide_directory) : -1;
        int mkdir_error = errno;
        free(wide_directory);
        if (mkdir_result == 0) {
            static volatile LONG fallback_reported;
            if (InterlockedCompareExchange(&fallback_reported, 1, 0) == 0) {
                (void)fprintf(stderr,