Improve loading of winmm in mtasa.dll

Author: botder

Client/loader-proxy/main.cpp

@@ -17,36 +17,18 @@
 #include <windows.h>
 #include <shlobj.h>
 
-__forceinline void SetupLibraryExports(HMODULE Handle) noexcept;
+namespace fs = std::filesystem;
 
-void DisplayErrorMessageBox(const std::wstring& message, const std::wstring& errorCode)
-{
-    std::wstring caption = L"MTA: San Andreas  [" + errorCode + L"]   (CTRL+C to copy)";
-    MessageBoxW(nullptr, message.c_str(), caption.c_str(), MB_OK | MB_TOPMOST | MB_ICONWARNING);
-    TerminateProcess(GetCurrentProcess(), 1);
-}
+void SetupLibraryExports(HMODULE Handle) noexcept;
+void DisplayErrorMessageBox(const std::wstring& message, const std::wstring& errorCode);
+auto GetProcessPath() -> fs::path;
+auto LoadWinmmLibrary() -> std::pair<HMODULE, DWORD>;
 
-auto GetProcessPath() -> std::filesystem::path
-{
-    std::wstring filePath(4096, L'\0');
-
-    while (true)
-    {
-        DWORD length = GetModuleFileNameW(nullptr, filePath.data(), static_cast<DWORD>(filePath.size() + 1));
-
-        if (GetLastError() == ERROR_INSUFFICIENT_BUFFER)
-        {
-            filePath.resize(filePath.capacity() * 2);
-            continue;
-        }
-
-        filePath.resize(length);
-        return {filePath};
-    }
-}
+static HMODULE core{};
+static DWORD   winmmSource = 0;
 
 static auto winmm = ([]() -> HMODULE {
-    HMODULE winmm = LoadLibraryExW(L"winmm.dll", nullptr, LOAD_LIBRARY_SEARCH_SYSTEM32);
+    auto [winmm, source] = LoadWinmmLibrary();
 
     if (!winmm)
     {
@@ -61,11 +43,10 @@ static auto winmm = ([]() -> HMODULE {
     }
 
     SetupLibraryExports(winmm);
+    winmmSource = source;
     return winmm;
 })();
 
-static HMODULE core{};
-
 BOOL WINAPI DllMain(HINSTANCE, DWORD reason, LPVOID)
 {
     if (reason == DLL_PROCESS_ATTACH)
@@ -134,3 +115,88 @@ BOOL WINAPI DllMain(HINSTANCE, DWORD reason, LPVOID)
 
     return TRUE;
 }
+
+extern "C" __declspec(dllexport) HMODULE mtasaGetLibraryHandle()
+{
+    return winmm;
+}
+
+extern "C" __declspec(dllexport) DWORD mtasaGetLibrarySource()
+{
+    return winmmSource;
+}
+
+void DisplayErrorMessageBox(const std::wstring& message, const std::wstring& errorCode)
+{
+    std::wstring caption = L"MTA: San Andreas  [" + errorCode + L"]   (CTRL+C to copy)";
+    MessageBoxW(nullptr, message.c_str(), caption.c_str(), MB_OK | MB_TOPMOST | MB_ICONWARNING);
+    TerminateProcess(GetCurrentProcess(), 1);
+}
+
+auto GetProcessPath() -> fs::path
+{
+    std::wstring filePath(4096, L'\0');
+
+    while (true)
+    {
+        DWORD length = GetModuleFileNameW(nullptr, filePath.data(), static_cast<DWORD>(filePath.size() + 1));
+
+        if (GetLastError() == ERROR_INSUFFICIENT_BUFFER)
+        {
+            filePath.resize(filePath.capacity() * 2);
+            continue;
+        }
+
+        filePath.resize(length);
+        return {filePath};
+    }
+}
+
+auto GetKnownFolderPath(REFKNOWNFOLDERID id, DWORD flags = 0) -> fs::path
+{
+    wchar_t* path{};
+
+    if (HRESULT hr = SHGetKnownFolderPath(id, flags, nullptr, &path); SUCCEEDED(hr))
+    {
+        fs::path result(path);
+        CoTaskMemFree(path);
+        return result;
+    }
+
+    return {};
+}
+
+auto GetSystemWinmmPath() -> fs::path
+{
+    std::error_code ec{};
+    fs::path        systemPath = GetKnownFolderPath(FOLDERID_SystemX86);
+
+    if (systemPath.empty() || !std::filesystem::is_directory(systemPath, ec))
+        return {};
+
+    fs::path winmmPath = systemPath / "winmm.dll";
+
+    if (!fs::is_regular_file(winmmPath, ec))
+        return {};
+
+    return winmmPath;
+}
+
+auto LoadWinmmLibrary() -> std::pair<HMODULE, DWORD>
+{
+    HMODULE winmm{};
+
+    if (winmm = LoadLibraryExW(L"winmm.dll", nullptr, LOAD_LIBRARY_SEARCH_SYSTEM32))
+        return {winmm, 1};
+
+    if (fs::path winmmPath = GetSystemWinmmPath(); !winmmPath.empty())
+    {
+        if (winmm = LoadLibraryW(winmmPath.wstring().c_str()))
+            return {winmm, 2};
+    }
+
+    if (winmm = LoadLibraryW(L"winmm.dll"))
+        return {winmm, 3};
+
+    return {nullptr, 0};
+}