APIHijack - A Library for easy DLL function hooking.

Introduction

Based on DelayLoadProfileDLL.CPP, by Matt Pietrek for MSJ February 2000. This code is intended to be included in a DLL inserted through a global Windows Hook (CBT hook for example). It will replace functions from other DLLs (e.g. DDRAW.DLL) with functions from your DLL.

Functions are hooked by passing a parameter structure to the HookAPICalls() function as follows:

SDLLHook D3DHook = 
{
    "DDRAW.DLL",
    false, NULL,    // Default hook disabled, NULL function pointer.
    {
        { "DirectDrawCreate", MyDirectDrawCreate },
        { NULL, NULL }
    }
};

BOOL APIENTRY DllMain( HINSTANCE hModule, DWORD fdwReason, LPVOID lpReserved)
{
    if ( fdwReason == DLL_PROCESS_ATTACH )  // When initializing....
    {
        hDLL = hModule;

        // We don't need thread notifications for what we're doing.  Thus, 
        // get rid of them, thereby eliminating some of the overhead of 
        // this DLL
        DisableThreadLibraryCalls( hModule );

        // Only hook the APIs if this is the right process.
        GetModuleFileName( GetModuleHandle( NULL ), Work, sizeof(Work) );
        PathStripPath( Work );

        if ( stricmp( Work, "myhooktarget.exe" ) == 0 )
            HookAPICalls( &D3DHook );
    }

    return TRUE;
}

Now all that remains is to get your DLL loaded into the target process.