BOOL WINAPI DetourProcessViaHelperDllsW()

in src/creatwth.cpp [1440:1536]
82 lines of code
12 McCabe index (conditional complexity)

BOOL WINAPI DetourProcessViaHelperDllsW(_In_ DWORD dwTargetPid,
                                        _In_ DWORD nDlls,
                                        _In_reads_(nDlls) LPCSTR *rlpDlls,
                                        _In_ PDETOUR_CREATE_PROCESS_ROUTINEW pfCreateProcessW)
{
    BOOL Result = FALSE;
    PROCESS_INFORMATION pi;
    STARTUPINFOW si;
    WCHAR szExe[MAX_PATH];
    WCHAR szCommand[MAX_PATH];
    PDETOUR_EXE_HELPER helper = NULL;
    HRESULT hr;
    WCHAR szDllName[MAX_PATH];
    int cchWrittenWideChar;
    DWORD nLen = GetEnvironmentVariableW(L"WINDIR", szExe, ARRAYSIZE(szExe));

    DETOUR_TRACE(("DetourProcessViaHelperDlls(pid=%lu,dlls=%lu)\n", dwTargetPid, nDlls));
    if (nDlls < 1 || nDlls > 4096) {
        SetLastError(ERROR_INVALID_PARAMETER);
        goto Cleanup;
    }
    if (!AllocExeHelper(&helper, dwTargetPid, nDlls, rlpDlls)) {
        goto Cleanup;
    }

    if (nLen == 0 || nLen >= ARRAYSIZE(szExe)) {
        goto Cleanup;
    }

#if DETOURS_OPTION_BITS
#if DETOURS_32BIT
    hr = StringCchCatW(szExe, ARRAYSIZE(szExe), L"\\sysnative\\rundll32.exe");
#else // !DETOURS_32BIT
    hr = StringCchCatW(szExe, ARRAYSIZE(szExe), L"\\syswow64\\rundll32.exe");
#endif // !DETOURS_32BIT
#else // DETOURS_OPTIONS_BITS
    hr = StringCchCatW(szExe, ARRAYSIZE(szExe), L"\\system32\\rundll32.exe");
#endif // DETOURS_OPTIONS_BITS
    if (!SUCCEEDED(hr)) {
        goto Cleanup;
    }

    //for East Asia languages and so on, like Chinese, print format with "%hs" can not work fine before user call _tsetlocale(LC_ALL,_T(".ACP"));
    //so we can't use "%hs" in format string, because the dll that contain this code would inject to any process, even not call _tsetlocale(LC_ALL,_T(".ACP")) before
    
    cchWrittenWideChar = MultiByteToWideChar(CP_ACP, 0, &helper->rDlls[0], -1, szDllName, ARRAYSIZE(szDllName));
    if (cchWrittenWideChar >= ARRAYSIZE(szDllName) || cchWrittenWideChar <= 0) {
        goto Cleanup;
    }
    hr = StringCchPrintfW(szCommand, ARRAYSIZE(szCommand),
        L"rundll32.exe \"%s\",#1", szDllName);
    if (!SUCCEEDED(hr)) {
        goto Cleanup;
    }

    ZeroMemory(&pi, sizeof(pi));
    ZeroMemory(&si, sizeof(si));
    si.cb = sizeof(si);

    DETOUR_TRACE(("DetourProcessViaHelperDlls(\"%ls\", \"%ls\")\n", szExe, szCommand));
    if (pfCreateProcessW(szExe, szCommand, NULL, NULL, FALSE, CREATE_SUSPENDED,
                         NULL, NULL, &si, &pi)) {

        if (!DetourCopyPayloadToProcess(pi.hProcess,
                                        DETOUR_EXE_HELPER_GUID,
                                        helper, helper->cb)) {
            DETOUR_TRACE(("DetourCopyPayloadToProcess failed: %lu\n", GetLastError()));
            TerminateProcess(pi.hProcess, ~0u);
            CloseHandle(pi.hProcess);
            CloseHandle(pi.hThread);
            goto Cleanup;
        }

        ResumeThread(pi.hThread);
        WaitForSingleObject(pi.hProcess, INFINITE);

        DWORD dwResult = 500;
        GetExitCodeProcess(pi.hProcess, &dwResult);

        CloseHandle(pi.hProcess);
        CloseHandle(pi.hThread);

        if (dwResult != 0) {
            DETOUR_TRACE(("Rundll32.exe failed: result=%lu\n", dwResult));
            goto Cleanup;
        }
        Result = TRUE;
    }
    else {
        DETOUR_TRACE(("CreateProcess failed: %lu\n", GetLastError()));
        goto Cleanup;
    }

  Cleanup:
    FreeExeHelper(&helper);
    return Result;
}