dllmain.cpp

#include "MinHook.h"

#if defined _M_X64
#pragma comment(lib, "libMinHook.x64.lib")
#elif defined _M_IX86
#pragma comment(lib, "libMinHook.x86.lib")
#endif

#include <cstdio>
#include <cstring>
#include <fstream>
#include <functional>
#include <iostream>
#include <string>

#include <Windows.h>


using FreeLibraryProc = BOOL (WINAPI *)(HMODULE);
FreeLibraryProc fpFreeLibrary = nullptr;

static std::ofstream logger;


BOOL WINAPI _FreeLibrary(HMODULE hModule)
{
	logger << "Intercepting call to FreeLibrary()" << std::endl;
	return fpFreeLibrary(hModule);
}

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID)
{
	switch (fdwReason)
	{
	case DLL_PROCESS_ATTACH:
		if (fpFreeLibrary != nullptr)
			break;

		logger.open("bwhook.log", std::ios::out | std::ios::app);
		logger << "Logging started" << std::endl;

		if (MH_Initialize() != MH_OK)
		{
			logger << "Failed to initialize MinHook" << std::endl;
			logger.close();
			return FALSE;
		}

		if (MH_CreateHook(&FreeLibrary, &_FreeLibrary, reinterpret_cast<LPVOID *>(&fpFreeLibrary)) != MH_OK)
		{
			logger << "Failed to create a FreeLibrary hook" << std::endl;
			logger.close();
			return FALSE;
		}

		if (MH_EnableHook(&FreeLibrary) != MH_OK)
		{
			logger << "Failed to enable FreeLibrary hook" << std::endl;
			logger.close();
			return FALSE;
		}
		break;
	case DLL_PROCESS_DETACH:
		MH_DisableHook(&FreeLibrary);
		MH_Uninitialize();
		logger << "Logging ended\n" << std::endl;
		logger.close();
		break;
	default:
		break;
	}

	return TRUE;
}