Introduce DirectPlay passthrough

source/VersionInfo.lua

@@ -1,7 +1,7 @@
 defines { 
     "rsc_FullName=\"DirectPlay Stub\"",
-    "rsc_MinorVersion=0",
+    "rsc_MinorVersion=1",
     "rsc_RevisionID=1",
     "rsc_BuildID=0",
-    "rsc_Copyright=\"2023\""
+    "rsc_Copyright=\"2023-2024\""
 }

source/dplayx.def

@@ -1,8 +1,9 @@
 LIBRARY DPLAYX
 EXPORTS
-	DirectPlayCreate=DirectPlayCreate_Stub @1
-	DirectPlayEnumerateA=DirectPlayEnumerate_Stub @2
-	DirectPlayEnumerateW=DirectPlayEnumerate_Stub @3
-	DirectPlayLobbyCreateA=DirectPlayLobbyCreate_Stub @4
-	DirectPlayLobbyCreateW=DirectPlayLobbyCreate_Stub @5
-	DirectPlayEnumerate=DirectPlayEnumerate_Stub @9
+	DirectPlayCreate @1
+	DirectPlayEnumerateA @2
+	DirectPlayEnumerateW @3
+	DirectPlayLobbyCreateA @4
+	DirectPlayLobbyCreateW @5
+	DirectPlayEnumerate @9
+	gdwDPlaySPRefCount @11

source/dplayx/dplayx.cpp

@@ -3,49 +3,88 @@
 
 #include <windows.h>
 #include <combaseapi.h>
+#include <ShlObj.h>
 
-#include "../dplay-stub.h"
+#include "../exportChecker.h"
+#include "stubs.h"
 
-HRESULT WINAPI DirectPlayCreate_Stub(LPGUID lpGUID, LPVOID* lplpDP, IUnknown* lpUnk)
+#include <filesystem>
+#include <mutex>
+
+static auto DirectPlayCreate_Func = &DirectPlayCreate_Stub;
+static auto DirectPlayEnumerate_Func = &DirectPlayEnumerate_Stub;
+static auto DirectPlayEnumerateA_Func = &DirectPlayEnumerate_Stub;
+static auto DirectPlayEnumerateW_Func = &DirectPlayEnumerate_Stub;
+static auto DirectPlayLobbyCreateA_Func = &DirectPlayLobbyCreate_Stub;
+static auto DirectPlayLobbyCreateW_Func = &DirectPlayLobbyCreate_Stub;
+
+static std::once_flag TryPassthroughFlag;
+static void DoTryPassthrough()
 {
-	if (lpUnk != nullptr)
-	{
-		return CLASS_E_NOAGGREGATION;
-	}
-	if (lpGUID == nullptr || lplpDP == nullptr)
+	PWSTR system32Path = nullptr;
+	if (SUCCEEDED(SHGetKnownFolderPath(FOLDERID_System, KF_FLAG_DEFAULT, nullptr, &system32Path)))
 	{
-		return DPERR_INVALIDPARAM;
+		const std::filesystem::path dllPath(std::filesystem::path(system32Path) / L"dplayx.dll");
+		if (CheckExports(dllPath.c_str(), {
+				"DirectPlayCreate", "DirectPlayEnumerate", "DirectPlayEnumerateA", "DirectPlayEnumerateW", "DirectPlayLobbyCreateA", "DirectPlayLobbyCreateW"
+			}))
+		{
+			HMODULE systemDplay = LoadLibraryW(dllPath.c_str());
+			if (systemDplay != nullptr)
+			{
+				DirectPlayCreate_Func = reinterpret_cast<decltype(DirectPlayCreate_Func)>(GetProcAddress(systemDplay, "DirectPlayCreate"));
+				DirectPlayEnumerate_Func = reinterpret_cast<decltype(DirectPlayEnumerate_Func)>(GetProcAddress(systemDplay, "DirectPlayEnumerate"));
+				DirectPlayEnumerateA_Func = reinterpret_cast<decltype(DirectPlayEnumerateA_Func)>(GetProcAddress(systemDplay, "DirectPlayEnumerateA"));
+				DirectPlayEnumerateW_Func = reinterpret_cast<decltype(DirectPlayEnumerateW_Func)>(GetProcAddress(systemDplay, "DirectPlayEnumerateW"));
+				DirectPlayLobbyCreateA_Func = reinterpret_cast<decltype(DirectPlayLobbyCreateA_Func)>(GetProcAddress(systemDplay, "DirectPlayLobbyCreateA"));
+				DirectPlayLobbyCreateW_Func = reinterpret_cast<decltype(DirectPlayLobbyCreateW_Func)>(GetProcAddress(systemDplay, "DirectPlayLobbyCreateW"));
+
+				// "Leak" the DLL handle on purpose
+			}
+		}
+
+		CoTaskMemFree(system32Path);
 	}
+}
 
-	*lplpDP = nullptr;
-	return DPERR_UNSUPPORTED;
+static void TryPassthrough()
+{
+	std::call_once(TryPassthroughFlag, DoTryPassthrough);
 }
 
-HRESULT WINAPI DirectPlayEnumerate_Stub(LPVOID lpEnumCallback, LPVOID /*lpContext*/)
+
+HRESULT WINAPI DirectPlayCreate(LPGUID lpGUID, LPVOID* lplpDP, IUnknown* lpUnk)
 {
-	if (lpEnumCallback == nullptr)
-	{
-		return DPERR_INVALIDPARAM;
-	}
-	return DP_OK;
+	TryPassthrough();
+	return DirectPlayCreate_Func(lpGUID, lplpDP, lpUnk);
 }
 
-HRESULT WINAPI DirectPlayLobbyCreate_Stub(LPGUID lpGUIDDSP, LPVOID* lplpDPL, IUnknown* lpUnk, void* lpData, DWORD dwDataSize)
+HRESULT WINAPI DirectPlayEnumerate(LPVOID lpEnumCallback, LPVOID lpContext)
 {
-	if (lpGUIDDSP != nullptr && *lpGUIDDSP != GUID_NULL)
-	{
-		return DPERR_INVALIDPARAM;
-	}
-	if (lpUnk != nullptr)
-	{
-		return CLASS_E_NOAGGREGATION;
-	}
-	if (lpData != nullptr || dwDataSize != 0)
-	{
-		return DPERR_INVALIDPARAM;
-	}
+	TryPassthrough();
+	return DirectPlayEnumerate_Func(lpEnumCallback, lpContext);
+}
+
+HRESULT WINAPI DirectPlayEnumerateA(LPVOID lpEnumCallback, LPVOID lpContext)
+{
+	TryPassthrough();
+	return DirectPlayEnumerateA_Func(lpEnumCallback, lpContext);
+}
 
-	// lplpDPL is not checked for validity in the real DLL...
-	*lplpDPL = nullptr;
-	return DPERR_UNSUPPORTED;
+HRESULT WINAPI DirectPlayEnumerateW(LPVOID lpEnumCallback, LPVOID lpContext)
+{
+	TryPassthrough();
+	return DirectPlayEnumerateW_Func(lpEnumCallback, lpContext);
+}
+
+HRESULT WINAPI DirectPlayLobbyCreateA(LPGUID lpGUIDDSP, LPVOID* lplpDPL, IUnknown* lpUnk, void* lpData, DWORD dwDataSize)
+{
+	TryPassthrough();
+	return DirectPlayLobbyCreateA_Func(lpGUIDDSP, lplpDPL, lpUnk, lpData, dwDataSize);
+}
+
+HRESULT WINAPI DirectPlayLobbyCreateW(LPGUID lpGUIDDSP, LPVOID* lplpDPL, IUnknown* lpUnk, void* lpData, DWORD dwDataSize)
+{
+	TryPassthrough();
+	return DirectPlayLobbyCreateW_Func(lpGUIDDSP, lplpDPL, lpUnk, lpData, dwDataSize);
 }

source/dplayx/stubs.cpp

@@ -0,0 +1,47 @@
+#include "stubs.h"
+
+HRESULT WINAPI DirectPlayCreate_Stub(LPGUID lpGUID, LPVOID* lplpDP, IUnknown* lpUnk)
+{
+	if (lpUnk != nullptr)
+	{
+		return CLASS_E_NOAGGREGATION;
+	}
+	if (lpGUID == nullptr || lplpDP == nullptr)
+	{
+		return DPERR_INVALIDPARAM;
+	}
+
+	*lplpDP = nullptr;
+	return DPERR_UNSUPPORTED;
+}
+
+HRESULT WINAPI DirectPlayEnumerate_Stub(LPVOID lpEnumCallback, LPVOID /*lpContext*/)
+{
+	if (lpEnumCallback == nullptr)
+	{
+		return DPERR_INVALIDPARAM;
+	}
+	return DP_OK;
+}
+
+HRESULT WINAPI DirectPlayLobbyCreate_Stub(LPGUID lpGUIDDSP, LPVOID* lplpDPL, IUnknown* lpUnk, void* lpData, DWORD dwDataSize)
+{
+	if (lpGUIDDSP != nullptr && *lpGUIDDSP != GUID_NULL)
+	{
+		return DPERR_INVALIDPARAM;
+	}
+	if (lpUnk != nullptr)
+	{
+		return CLASS_E_NOAGGREGATION;
+	}
+	if (lpData != nullptr || dwDataSize != 0)
+	{
+		return DPERR_INVALIDPARAM;
+	}
+
+	// lplpDPL is not checked for validity in the real DLL...
+	*lplpDPL = nullptr;
+	return DPERR_UNSUPPORTED;
+}
+
+DWORD gdwDPlaySPRefCount = 0;

source/dplayx/stubs.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#define WIN32_LEAN_AND_MEAN
+#define NOMINMAX
+
+#include <windows.h>
+#include <combaseapi.h>
+
+#include "../dplay-stub.h"
+
+HRESULT WINAPI DirectPlayCreate_Stub(LPGUID lpGUID, LPVOID* lplpDP, IUnknown* lpUnk);
+HRESULT WINAPI DirectPlayEnumerate_Stub(LPVOID lpEnumCallback, LPVOID /*lpContext*/);
+HRESULT WINAPI DirectPlayLobbyCreate_Stub(LPGUID lpGUIDDSP, LPVOID* lplpDPL, IUnknown* lpUnk, void* lpData, DWORD dwDataSize);

source/exportChecker.cpp

@@ -0,0 +1,42 @@
+#include "exportChecker.h"
+
+#define WIN32_LEAN_AND_MEAN
+#define NOMINMAX
+
+#include <windows.h>
+
+#include <vector>
+
+bool CheckExports(const wchar_t* path, std::initializer_list<std::string_view> exports)
+{
+	std::vector<std::string_view> exportsToCheck(exports);
+
+	HMODULE file = LoadLibraryExW(path, nullptr, LOAD_LIBRARY_AS_IMAGE_RESOURCE);
+	if (file != nullptr)
+	{
+		DWORD_PTR instance = reinterpret_cast<DWORD_PTR>(file) & ~3;
+		const PIMAGE_NT_HEADERS ntHeader = reinterpret_cast<PIMAGE_NT_HEADERS>(instance + reinterpret_cast<PIMAGE_DOS_HEADER>(instance)->e_lfanew);
+		const DWORD exportVA = ntHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress;
+		if (exportVA != 0)
+		{
+			const PIMAGE_EXPORT_DIRECTORY exportDirectory = reinterpret_cast<PIMAGE_EXPORT_DIRECTORY>(instance + exportVA);
+			const DWORD* functionNames = reinterpret_cast<DWORD*>(instance + exportDirectory->AddressOfNames);
+			for (DWORD i = 0; i < exportDirectory->NumberOfNames; i++)
+			{
+				const char* nameRva = reinterpret_cast<const char*>(instance + functionNames[i]);
+				auto it = std::find(exportsToCheck.begin(), exportsToCheck.end(), nameRva);
+				if (it != exportsToCheck.end())
+				{
+					exportsToCheck.erase(it);
+					if (exportsToCheck.empty())
+					{
+						// Early out if all required functions are found
+						break;
+					}
+				}
+			}
+		}
+		FreeLibrary(file);
+	}
+	return exportsToCheck.empty();
+}

source/exportChecker.h

@@ -0,0 +1,6 @@
+#pragma once
+
+#include <initializer_list>
+#include <string_view>
+
+bool CheckExports(const wchar_t* path, std::initializer_list<std::string_view> exports);