Function cbm_resolve_comspec

src/foundation/compat_fs.c:179–191

Resolve the shell explicitly — %COMSPEC%, else \cmd.exe — so it * can be passed as lpApplicationName and CreateProcess never walks the search * path (no cmd.exe planting from a hostile CWD). Heap string; caller frees. */

 * can be passed as lpApplicationName and CreateProcess never walks the search
 * path (no cmd.exe planting from a hostile CWD). Heap string; caller frees. */
static wchar_t *cbm_resolve_comspec(void) {
    wchar_t buf[MAX_PATH];
    const wchar_t suffix[] = L"\\cmd.exe";
    DWORD n = GetEnvironmentVariableW(L"COMSPEC", buf, MAX_PATH);
    if (n == 0 || n >= MAX_PATH) {
        UINT sn = GetSystemDirectoryW(buf, MAX_PATH);
        if (sn == 0 || (size_t)sn + wcslen(suffix) >= MAX_PATH) {
            return NULL;
        }
        wmemcpy(buf + sn, suffix, wcslen(suffix) + 1);
    }
    return _wcsdup(buf);
}

/* On failure returns NULL with *stage naming the failing step and *gle the
 * GetLastError value captured at that step (0 when errno is the signal). */