SilentPatch/DDraw/dllmain.cpp

#define WIN32_LEAN_AND_MEAN
#define WINVER 0x0501
#define _WIN32_WINNT 0x0501

#include <windows.h>
#include <stdio.h>
#include <Shlwapi.h>
#include <ShlObj.h>
#include "MemoryMgr.h"
#include "Patterns.h"

#pragma comment(lib, "shlwapi.lib")

extern "C" HRESULT WINAPI DirectDrawCreateEx(GUID FAR *lpGUID, LPVOID *lplpDD, REFIID iid, IUnknown FAR *pUnkOuter)
{
	static HRESULT	(WINAPI *pDirectDrawCreateEx)(GUID FAR*, LPVOID*, REFIID, IUnknown FAR*);
	if ( pDirectDrawCreateEx == nullptr )
	{
		wchar_t		wcSystemPath[MAX_PATH];
		GetSystemDirectoryW(wcSystemPath, MAX_PATH);
		PathAppendW(wcSystemPath, L"ddraw.dll");

		HMODULE		hLib = LoadLibraryW(wcSystemPath);
		pDirectDrawCreateEx = (HRESULT(WINAPI*)(GUID FAR*, LPVOID*, REFIID, IUnknown FAR*))GetProcAddress(hLib, "DirectDrawCreateEx");
	}
	return pDirectDrawCreateEx(lpGUID, lplpDD, iid, pUnkOuter);
}

char** ppUserFilesDir;

char* GetMyDocumentsPath()
{
	static char	cUserFilesPath[MAX_PATH];

	if ( cUserFilesPath[0] == '\0' )
	{	
		SHGetFolderPathA(nullptr, CSIDL_MYDOCUMENTS, nullptr, SHGFP_TYPE_CURRENT, cUserFilesPath);
		PathAppendA(cUserFilesPath, *ppUserFilesDir);

		CreateDirectoryA(cUserFilesPath, nullptr);
	}
	return cUserFilesPath;
}


void InjectHooks()
{
	using namespace Memory::VP;

	static char		aNoDesktopMode[64];

	RECT			desktop;
	GetWindowRect(GetDesktopWindow(), &desktop);
	sprintf_s(aNoDesktopMode, "Cannot find %dx%dx32 video mode", desktop.right, desktop.bottom);

	if (*(DWORD*)0x5C1E75 == 0xB85548EC)
	{
		// III 1.0
		ppUserFilesDir = (char**)0x580C16;
		InjectHook(0x580BB0, GetMyDocumentsPath, PATCH_JUMP);

		Patch<DWORD>(0x581E5E, desktop.right);
		Patch<DWORD>(0x581E68, desktop.bottom);
		Patch<BYTE>(0x581E72, 32);
		Patch<const char*>(0x581EA8, aNoDesktopMode);

		// No 12mb vram check
		Patch<BYTE>(0x581411, 0xEB);

		// No DirectPlay dependency
		Patch<BYTE>(0x5812D6, 0xB8);
		Patch<DWORD>(0x5812D7, 0x900);
	}
	else if (*(DWORD*)0x5C2135 == 0xB85548EC)
	{
		// III 1.1
		ppUserFilesDir = (char**)0x580F66;
		InjectHook(0x580F00, GetMyDocumentsPath, PATCH_JUMP);

		Patch<DWORD>(0x58219E, desktop.right);
		Patch<DWORD>(0x5821A8, desktop.bottom);
		Patch<BYTE>(0x5821B2, 32);
		Patch<const char*>(0x5821E8, aNoDesktopMode);

		// No 12mb vram check
		Patch<BYTE>(0x581753, 0xEB);

		// No DirectPlay dependency
		Patch<BYTE>(0x581620, 0xB8);
		Patch<DWORD>(0x581621, 0x900);
	}
	else if (*(DWORD*)0x5C6FD5 == 0xB85548EC)
	{
		// III Steam
		ppUserFilesDir = (char**)0x580E66;
		InjectHook(0x580E00, GetMyDocumentsPath, PATCH_JUMP);

		Patch<DWORD>(0x58208E, desktop.right);
		Patch<DWORD>(0x582098, desktop.bottom);
		Patch<BYTE>(0x5820A2, 32);
		Patch<const char*>(0x5820D8, aNoDesktopMode);

		// No 12mb vram check
		Patch<BYTE>(0x581653, 0xEB);

		// No DirectPlay dependency
		Patch<BYTE>(0x581520, 0xB8);
		Patch<DWORD>(0x581521, 0x900);
	}

	else if (*(DWORD*)0x667BF5 == 0xB85548EC)
	{
		// VC 1.0
		ppUserFilesDir = (char**)0x6022AA;
		InjectHook(0x602240, GetMyDocumentsPath, PATCH_JUMP);

		InjectHook(0x601A40, GetMyDocumentsPath, PATCH_CALL);
		InjectHook(0x601A45, 0x601B2F, PATCH_JUMP);

		Patch<DWORD>(0x600E7E, desktop.right);
		Patch<DWORD>(0x600E88, desktop.bottom);
		Patch<BYTE>(0x600E92, 32);
		Patch<const char*>(0x600EC8, aNoDesktopMode);

		// No 12mb vram check
		Patch<BYTE>(0x601E26, 0xEB);

		// No DirectPlay dependency
		Patch<BYTE>(0x601CA0, 0xB8);
		Patch<DWORD>(0x601CA1, 0x900);
	}
	else if (*(DWORD*)0x667C45 == 0xB85548EC)
	{
		// VC 1.1
		ppUserFilesDir = (char**)0x60228A;
		InjectHook(0x602220, GetMyDocumentsPath, PATCH_JUMP);

		InjectHook(0x601A70, GetMyDocumentsPath, PATCH_CALL);
		InjectHook(0x601A75, 0x601B5F, PATCH_JUMP);

		Patch<DWORD>(0x600E9E, desktop.right);
		Patch<DWORD>(0x600EA8, desktop.bottom);
		Patch<BYTE>(0x600EB2, 32);
		Patch<const char*>(0x600EE8, aNoDesktopMode);

		// No 12mb vram check
		Patch<BYTE>(0x601E56, 0xEB);

		// No DirectPlay dependency
		Patch<BYTE>(0x601CD0, 0xB8);
		Patch<DWORD>(0x601CD1, 0x900);
	}
	else if (*(DWORD*)0x666BA5 == 0xB85548EC)
	{
		// VC Steam
		ppUserFilesDir = (char**)0x601ECA;
		InjectHook(0x601E60, GetMyDocumentsPath, PATCH_JUMP);

		InjectHook(0x6016B0, GetMyDocumentsPath, PATCH_CALL);
		InjectHook(0x6016B5, 0x60179F, PATCH_JUMP);

		Patch<DWORD>(0x600ADE, desktop.right);
		Patch<DWORD>(0x600AE8, desktop.bottom);
		Patch<BYTE>(0x600AF2, 32);
		Patch<const char*>(0x600B28, aNoDesktopMode);

		// No 12mb vram check
		Patch<BYTE>(0x601A96, 0xEB);

		// No DirectPlay dependency
		Patch<BYTE>(0x601910, 0xB8);
		Patch<DWORD>(0x601911, 0x900);
	}
}


static bool FixRwcseg_Patterns();
static bool rwcsegUnprotected = false;

static void ProcHook()
{
	static bool		bPatched = false;
	if ( !bPatched )
	{
		bPatched = true;

		InjectHooks();

		if ( !rwcsegUnprotected )
		{
			rwcsegUnprotected = FixRwcseg_Patterns();
		}
	}
}

static VOID (WINAPI* pOrgGetStartupInfoA)(LPSTARTUPINFOA);
VOID WINAPI GetStartupInfoA_Hook(LPSTARTUPINFOA lpStartupInfo)
{
	ProcHook();
	pOrgGetStartupInfoA(lpStartupInfo);
}

static uint8_t orgCode[5];
static decltype(SystemParametersInfoA)* pOrgSystemParametersInfoA;
BOOL WINAPI SystemParametersInfoA_OverwritingHook( UINT uiAction, UINT uiParam, PVOID pvParam, UINT fWinIni )
{
	ProcHook();
	Memory::VP::Patch( pOrgSystemParametersInfoA, { orgCode[0], orgCode[1], orgCode[2], orgCode[3], orgCode[4] } );
	return pOrgSystemParametersInfoA( uiAction, uiParam, pvParam, fWinIni );
}

static bool FixRwcseg_Header()
{
	HINSTANCE					hInstance = GetModuleHandle(nullptr);
	PIMAGE_NT_HEADERS			ntHeader = (PIMAGE_NT_HEADERS)((DWORD_PTR)hInstance + ((PIMAGE_DOS_HEADER)hInstance)->e_lfanew);

	// Give _rwcseg proper access rights
	PIMAGE_SECTION_HEADER	pSection = IMAGE_FIRST_SECTION(ntHeader);

	for ( SIZE_T i = 0, j = ntHeader->FileHeader.NumberOfSections; i < j; i++, pSection++ )
	{
		if ( *(uint64_t*)(pSection->Name) == 0x006765736377725F )	// _rwcseg
		{
			DWORD	dwProtect;
			VirtualProtect((LPVOID)((DWORD_PTR)hInstance + pSection->VirtualAddress), pSection->Misc.VirtualSize, PAGE_EXECUTE_READ, &dwProtect);

			DWORD Characteristics = pSection->Characteristics;
			if ( (Characteristics & IMAGE_SCN_CNT_CODE) == 0 )
			{
				Characteristics |= IMAGE_SCN_CNT_CODE;
				Memory::VP::Patch( &ntHeader->OptionalHeader.SizeOfCode, ntHeader->OptionalHeader.SizeOfCode + pSection->Misc.VirtualSize );
			}
			if ( (Characteristics & IMAGE_SCN_CNT_INITIALIZED_DATA) != 0 )
			{
				Characteristics &= ~(IMAGE_SCN_CNT_INITIALIZED_DATA);
				Memory::VP::Patch( &ntHeader->OptionalHeader.SizeOfInitializedData, ntHeader->OptionalHeader.SizeOfInitializedData - pSection->Misc.VirtualSize );
			}
			if ( (Characteristics & IMAGE_SCN_CNT_UNINITIALIZED_DATA) != 0 )
			{
				Characteristics &= ~(IMAGE_SCN_CNT_UNINITIALIZED_DATA);
				Memory::VP::Patch( &ntHeader->OptionalHeader.SizeOfUninitializedData, ntHeader->OptionalHeader.SizeOfUninitializedData - pSection->Misc.VirtualSize );
			}
			Memory::VP::Patch( &pSection->Characteristics, Characteristics );
			return true;
		}
	}
	return false;
}

static bool FixRwcseg_Patterns()
{
	using namespace hook;

	auto begin = pattern( "55 8B EC 50 53 51 52 8B 5D 14 8B 4D 10 8B 45 0C 8B 55 08" ).count_hint(1000);
	auto end = pattern( "9B D9 3D ? ? ? ? 81 25 ? ? ? ? FF FC FF FF 83 0D ? ? ? ? 3F" ).count_hint(1000);

	if ( begin.count_hint(1).size() == 1 && end.count_hint(1).size() == 1 )
	{
		const ptrdiff_t size = (intptr_t)end.get_first( 24 ) - (intptr_t)begin.get_first();
		if ( size > 0 )
		{
			DWORD dwProtect;
			VirtualProtect( begin.get_first(), size, PAGE_EXECUTE_READ, &dwProtect );
			return true;
		}
	}
	return false;
}

static bool PatchIAT()
{
	HINSTANCE					hInstance = GetModuleHandle(nullptr);
	PIMAGE_NT_HEADERS			ntHeader = (PIMAGE_NT_HEADERS)((DWORD_PTR)hInstance + ((PIMAGE_DOS_HEADER)hInstance)->e_lfanew);

	// Find IAT	
	PIMAGE_IMPORT_DESCRIPTOR	pImports = (PIMAGE_IMPORT_DESCRIPTOR)((DWORD_PTR)hInstance + ntHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress);

	// Find kernel32.dll
	for ( ; pImports->Name != 0; pImports++ )
	{
		if ( !_stricmp((const char*)((DWORD_PTR)hInstance + pImports->Name), "KERNEL32.DLL") )
		{
			if ( pImports->OriginalFirstThunk == 0 ) return false;

			PIMAGE_IMPORT_BY_NAME*		pFunctions = (PIMAGE_IMPORT_BY_NAME*)((DWORD_PTR)hInstance + pImports->OriginalFirstThunk);

			// kernel32.dll found, find GetStartupInfoA
			for ( ptrdiff_t j = 0; pFunctions[j] != nullptr; j++ )
			{
				if ( !strcmp((const char*)((DWORD_PTR)hInstance + pFunctions[j]->Name), "GetStartupInfoA") )
				{
					// Overwrite the address with the address to a custom GetStartupInfoA
					DWORD			dwProtect[2];
					DWORD_PTR*		pAddress = &((DWORD_PTR*)((DWORD_PTR)hInstance + pImports->FirstThunk))[j];

					VirtualProtect(pAddress, sizeof(DWORD_PTR), PAGE_EXECUTE_READWRITE, &dwProtect[0]);
					pOrgGetStartupInfoA = **(VOID(WINAPI**)(LPSTARTUPINFOA))pAddress;
					*pAddress = (DWORD_PTR)GetStartupInfoA_Hook;
					VirtualProtect(pAddress, sizeof(DWORD_PTR), dwProtect[0], &dwProtect[1]);

					return true;
				}
			}
		}
	}
	return false;
}

static bool PatchIAT_ByPointers()
{
	pOrgSystemParametersInfoA = SystemParametersInfoA;
	memcpy( orgCode, pOrgSystemParametersInfoA, sizeof(orgCode) );
	Memory::VP::InjectHook( pOrgSystemParametersInfoA, SystemParametersInfoA_OverwritingHook, PATCH_JUMP );
	return true;
}

static void ApplyDDrawHooks()
{
	rwcsegUnprotected = FixRwcseg_Header();

	bool getStartupInfoHooked = PatchIAT();
	if ( !getStartupInfoHooked )
	{
		PatchIAT_ByPointers();
	}
}

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
{
	UNREFERENCED_PARAMETER(hinstDLL);
	UNREFERENCED_PARAMETER(lpvReserved);

	if ( fdwReason == DLL_PROCESS_ATTACH )
	{
		ApplyDDrawHooks();
	}

	return TRUE;
}