CoopAllTheThings/hook/src/dllmain.cpp

// coop_hook.dll -- injected into the target game by the host.
//
// On load it opens the host's shared-memory channel (named by this process's
// pid), hooks XInput so the game reads the forwarded controller state, and
// spoofs focus so the game keeps running while the tool holds the real OS focus.
// All real work happens on a worker thread; DllMain only kicks it off to stay
// clear of the loader lock.

#include <atomic>

#include <windows.h>

#include <objbase.h>

#include "audio_hook.hpp"
#include "coop/audio_ring.hpp"
#include "coop/log_ring.hpp"
#include "coop/shared_memory.hpp"
#include "debug_log.hpp"
#include "focus_spoof.hpp"
#include "hook_registry.hpp"
#include "ipc_client.hpp"
#include "xinput_hook.hpp"

namespace
{

coop::hook::IpcClient g_ipc;
std::atomic<bool> g_running{true};
coop::SharedMemory g_audio_shm; // the host's audio ring, opened when present
coop::SharedMemory g_log_shm;   // the host's log ring, opened when present

DWORD WINAPI worker_thread(LPVOID)
{
	coop::hook::logf("worker_thread: started");

	// The host creates the mapping around injection time; give it a few seconds.
	if (!g_ipc.connect(/*attempts=*/200, /*delay_ms=*/25))
	{
		coop::hook::logf("worker_thread: IPC connect FAILED (no host mapping); exiting");
		return 0;
	}
	// Attach the host's log ring first so the rest of bring-up streams to the Log
	// window. The host creates it at injection time; it's normally already there.
	{
		const std::wstring log_name = coop::log_ring_name(GetCurrentProcessId());
		if (g_log_shm.open(log_name, coop::log_ring_total_size(coop::kLogCapacity)))
		{
			auto* lr = g_log_shm.as<coop::LogRing>();
			if (coop::log_ring_valid(*lr))
			{
				coop::hook::set_log_ring(lr);
			}
			else
			{
				g_log_shm.reset();
			}
		}
	}

	coop::hook::logf("worker_thread: IPC connected");

	// The audio render-hook instantiates a COM enumerator on this thread.
	const bool com_ok = SUCCEEDED(CoInitializeEx(nullptr, COINIT_MULTITHREADED));
	coop::hook::logf("worker_thread: CoInitializeEx com_ok=%d", com_ok ? 1 : 0);

	bool xinput_installed = false;
	bool focus_installed = false;
	bool audio_installed = false;
	bool audio_ring_open = false;

	// Each tick, reconcile each subsystem with the host's requested state: install
	// what's wanted but missing (modules / the game window may appear lazily) and
	// remove what's no longer wanted (the host toggled it off). Beat a heartbeat so
	// the host can see the hook is alive.
	while (g_running.load(std::memory_order_relaxed))
	{
		// --- Input (XInput) ---
		const bool want_input = g_ipc.subsystem_install_requested(coop::HookSubsys_Input);
		if (want_input && !xinput_installed)
		{
			xinput_installed = coop::hook::install_xinput_hooks(g_ipc);
		}
		else if (!want_input && xinput_installed)
		{
			coop::hook::remove_xinput_hooks();
			xinput_installed = false;
		}

		// --- Focus spoof ---
		const bool want_focus = g_ipc.subsystem_install_requested(coop::HookSubsys_Focus);
		if (want_focus && !focus_installed)
		{
			focus_installed = coop::hook::install_focus_spoof(g_ipc);
		}
		else if (!want_focus && focus_installed)
		{
			coop::hook::remove_focus_spoof();
			focus_installed = false;
		}

		// --- Audio render-hook ---
		// Install even before the host's ring exists so render streams are counted
		// regardless; attach the ring (enabling capture+silence) once it appears.
		const bool want_audio = com_ok && g_ipc.subsystem_install_requested(coop::HookSubsys_Audio);
		if (want_audio && !audio_installed)
		{
			audio_installed = coop::hook::install_audio_hooks(g_ipc, nullptr);
			if (audio_installed)
			{
				coop::hook::logf("worker_thread: audio hooks installed");
				audio_ring_open = false; // re-attach the ring below after a reinstall
			}
		}
		else if (!want_audio && audio_installed)
		{
			coop::hook::remove_audio_hooks();
			audio_installed = false;
			audio_ring_open = false;
			coop::hook::logf("worker_thread: audio hooks removed (host request)");
		}

		if (audio_installed && !audio_ring_open)
		{
			const std::wstring name = coop::audio_ring_name(GetCurrentProcessId());
			if (!g_audio_shm.valid())
			{
				g_audio_shm.open(name, coop::audio_ring_total_size(coop::kAudioRingCapacity));
			}
			if (g_audio_shm.valid())
			{
				auto* ring = g_audio_shm.as<coop::AudioRingHeader>();
				if (coop::audio_ring_valid(*ring))
				{
					coop::hook::set_audio_ring(ring);
					audio_ring_open = true;
					coop::hook::logf("worker_thread: audio ring opened");
				}
				else
				{
					g_audio_shm.reset(); // present but not our contract; retry
				}
			}
		}
		// The primary stream is often registered before the ring is attached (or the
		// host re-inits the ring on a mirror re-toggle, clearing its format); keep
		// the format published so the host consumes the ring instead of falling back.
		if (audio_ring_open)
		{
			coop::hook::republish_audio_format();
		}
		coop::hook::update_input_diagnostics(g_ipc); // refreshes each tick; registrations can change
		coop::hook::hook_publish(g_ipc);             // installed-hooks list + call counts
		g_ipc.heartbeat();
		Sleep(250);
	}

	if (com_ok)
	{
		CoUninitialize();
	}
	return 0;
}

} // namespace

BOOL APIENTRY DllMain(HMODULE module, DWORD reason, LPVOID reserved)
{
	switch (reason)
	{
	case DLL_PROCESS_ATTACH:
		DisableThreadLibraryCalls(module);
		if (HANDLE thread = CreateThread(nullptr, 0, &worker_thread, nullptr, 0, nullptr))
		{
			CloseHandle(thread);
		}
		break;
	case DLL_PROCESS_DETACH:
		// Skip cleanup when the process is tearing down (reserved != null): the
		// loader is already unwinding and touching other modules is unsafe.
		if (reserved == nullptr)
		{
			g_running.store(false, std::memory_order_relaxed);
			coop::hook::set_log_ring(nullptr);
			coop::hook::remove_focus_spoof();
			coop::hook::remove_xinput_hooks();
			coop::hook::remove_audio_hooks();
			coop::hook::hook_registry_reset();
		}
		break;
	default:
		break;
	}
	return TRUE;
}