A header-only library for proxying DLLs with one function call:

UPD::CreateProxy(dll);

• No .masm or other assembly files required
• No module definition files (.def) files required
• No project configuration required
• Built DLL can dynamically proxy any supported DLL without rebuilding (just rename the DLL)
• Easily create callbacks for exported functions
• No race conditions (exported functions will wait for proxy creation)
• No LoadLibrary calls within DllMain
• Works for 32-bit and 64-bit games (32-bit has limited support!)

A simple DLL with a DllMain like this is all that is needed:

#include <Windows.h> #include "UniversalProxyDLL.h" BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved) { if (fdwReason == DLL_PROCESS_ATTACH) { UPD::OpenDebugTerminal(); UPD::CreateProxy(hinstDLL); } return TRUE; }

That's it! The DLL will then be proxied properly.

In the following example, Elden Ring was proxied with a dxgi.dll proxy:

Note: The debug terminal is optional.

From there you can create a new thread and do the usual proxy DLL stuff:

#include <Windows.h> #include "UniversalProxyDLL.h" DWORD WINAPI NewThread(LPVOID lpParam) { printf("Doing some very naughty stuff\n"); char* p = nullptr; char c = *p; return 0; } BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved) { if (fdwReason == DLL_PROCESS_ATTACH) { UPD::OpenDebugTerminal(); UPD::CreateProxy(hinstDLL); CreateThread(0, 0, &NewThread, NULL, 0, NULL); } return TRUE; }

You may add callbacks back to your own code for when an exported function is called:

#include <Windows.h> #include "UniversalProxyDLL.h" using FpDirectInput8Create = HRESULT (*)(HINSTANCE, DWORD, REFIID, LPVOID*, LPUNKNOWN); void* fpDirectInput8Create = nullptr; HRESULT CallbackDirectInput8Create(HINSTANCE hinst, DWORD dwVersion, REFIID riidltf, LPVOID* ppvOut, LPUNKNOWN punkOuter) { printf("Callback called!\n"); return (*(FpDirectInput8Create*)fpDirectInput8Create)(hinst, dwVersion, riidltf, ppvOut, punkOuter); } BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved) { if (fdwReason == DLL_PROCESS_ATTACH) { UPD::OpenDebugTerminal(); fpDirectInput8Create = UPD::RegisterCallback("DirectInput8Create", &CallbackDirectInput8Create); UPD::CreateProxy(hinstDLL); } return TRUE; }

Dinput8.dll was proxied in this example.

Your callback will be called directly prior to the exported function being executed.

Note: It's crucial that the function signature for the callback exactly matches the function signature of the exported function. For instance, the function signature for "DirectInput8Create" used in the example was found here.

As for the return with a call to the original exported function - in some cases you might get away with omitting it, but I wouldn't recommend it.

Yes, in practice this project is not truly universal, only in theory. See section "Adding support for a DLL".

The most common proxy DLLs are supported out of the box:

• dxgi
• d3d10
• d3d11
• d3d12 (see issue #1)
• dinput8
• XInput1_3
• XInput1_4
• steam_api64
• steam_api
• opengl32
• winhttp
• bink2w64

Note: I do not guarantee that all supported DLLs will work for 32-bit games. Trial and error is required in this case.

Adding support for a DLL is simple. In the "scripts" folder you will find some Python scripts.

Use the create_export_list.py script by running python create_export_list.py <path_to_dll>. This will create a "<dll>_export_list.txt" file in the script folder:

Copy the contents of the generated file to somewhere at the bottom of "UniversalProxyDLL.h" and build:

The DLL should now be proxied correctly.

Note: If your DLL has a higher number of exports than the current amount of Forward and ForwardOrdinal functions, you must also use the scripts create_export_ordinals.py and create_forward_functions.py to generate an amount of functions equal to or higher than the number of exports of your DLL.

Also note: Some system DLLs such as user32 may refuse to be proxied!

To check which DLLs you can use to create proxies for specific games, you may for example use the dumpbin tool provided with Visual Studio:

Some of my other projects, such as DirectXHook and Elden Mod Loader.

If you find that a DLL is not supported and you've added the exports yourself, I'd appreciate if you'd create a PR so the exports can be made available to others. Thank you.

LICENSE.md