CoopAllTheThings/tests/hook_selftest.cpp

// In-process self-test for the core forwarding logic: IPC publish/read + the
// SafetyHook XInput interception. No injection or physical controller needed --
// this process plays both host and game. Exits 0 on pass, 1 on failure.

#include <cstddef>
#include <cstdio>

#include <windows.h>
#include <xinput.h>

#include "coop/protocol.hpp"
#include "coop/shared_memory.hpp"
#include "ipc_client.hpp"
#include "xinput_hook.hpp"

using namespace coop;

namespace
{

constexpr std::uint16_t kButtonA = 0x1000;
constexpr std::uint16_t kButtonB = 0x2000;

int g_failures = 0;

void check(bool ok, const char* what)
{
	if (!ok)
	{
		std::printf("  FAIL: %s\n", what);
		++g_failures;
	}
}

} // namespace

// Exercises every export the game touches on one loaded xinput DLL, so the inline
// hook + trampoline over *that DLL's* real prologue is actually called -- not just
// installed. Older games load older variants (e.g. xinput1_3.dll) whose export
// prologues differ, which is where a 32-bit trampoline-relocation fault hides.
void exercise_dll(const wchar_t* dll_name)
{
	HMODULE m = GetModuleHandleW(dll_name);
	if (m == nullptr)
	{
		return; // not loaded on this machine; nothing to exercise
	}
	char tag[96];

	using GetState_t = DWORD(WINAPI*)(DWORD, XINPUT_STATE*);
	using SetState_t = DWORD(WINAPI*)(DWORD, XINPUT_VIBRATION*);
	using GetCaps_t = DWORD(WINAPI*)(DWORD, DWORD, XINPUT_CAPABILITIES*);

	auto get_state = reinterpret_cast<GetState_t>(GetProcAddress(m, "XInputGetState"));
	auto get_state_ex = reinterpret_cast<GetState_t>(GetProcAddress(m, MAKEINTRESOURCEA(100)));
	auto get_caps = reinterpret_cast<GetCaps_t>(GetProcAddress(m, "XInputGetCapabilities"));
	auto set_state = reinterpret_cast<SetState_t>(GetProcAddress(m, "XInputSetState"));

	if (get_state != nullptr)
	{
		XINPUT_STATE s = {};
		std::snprintf(tag, sizeof(tag), "%ls XInputGetState forwards state", dll_name);
		check(get_state(0, &s) == ERROR_SUCCESS && s.dwPacketNumber == 7, tag);
	}
	if (get_state_ex != nullptr)
	{
		XINPUT_STATE s = {};
		std::snprintf(tag, sizeof(tag), "%ls XInputGetStateEx (ord 100) forwards state", dll_name);
		check(get_state_ex(0, &s) == ERROR_SUCCESS && s.dwPacketNumber == 7, tag);
	}
	if (get_caps != nullptr)
	{
		XINPUT_CAPABILITIES c = {};
		std::snprintf(tag, sizeof(tag), "%ls XInputGetCapabilities reports gamepad", dll_name);
		check(get_caps(0, 0, &c) == ERROR_SUCCESS && c.Type == XINPUT_DEVTYPE_GAMEPAD, tag);
	}
	if (set_state != nullptr)
	{
		// A game commonly rumbles in response to a button press; this is the call
		// path "crashes as soon as a button is pressed" pointed at.
		XINPUT_VIBRATION v = {};
		v.wLeftMotorSpeed = 0x8000;
		v.wRightMotorSpeed = 0x4000;
		std::snprintf(tag, sizeof(tag), "%ls XInputSetState (rumble) accepted, no crash", dll_name);
		check(set_state(0, &v) == ERROR_SUCCESS, tag);
	}
}

void dump_layout()
{
	std::printf("LAYOUT sizeof(SharedBlock)=%zu CoopPadState=%zu\n", sizeof(SharedBlock), sizeof(CoopPadState));
	std::printf("LAYOUT off pads=%zu sequence=%zu status=%zu control=%zu video=%zu\n",
	            offsetof(SharedBlock, pads), offsetof(SharedBlock, sequence), offsetof(SharedBlock, status),
	            offsetof(SharedBlock, control), offsetof(SharedBlock, video));
	std::printf("LAYOUT HookStatus sizeof=%zu get_state_calls=%zu attached=%zu audio_streams=%zu hook_entries=%zu\n",
	            sizeof(HookStatus), offsetof(HookStatus, get_state_calls), offsetof(HookStatus, attached),
	            offsetof(HookStatus, audio_streams), offsetof(HookStatus, hook_entries));
	std::printf("LAYOUT VideoShare sizeof=%zu present_calls=%zu HookControl sizeof=%zu\n", sizeof(VideoShare),
	            offsetof(VideoShare, present_calls), sizeof(HookControl));
}

int main()
{
	dump_layout();

	// --- Host side: create the section (named by our pid) and publish a pad. ---
	SharedMemory shm;
	if (!shm.create(shared_memory_name(GetCurrentProcessId()), sizeof(SharedBlock)))
	{
		std::printf("FAIL: could not create shared memory\n");
		return 1;
	}
	auto* block = shm.as<SharedBlock>();
	block->version = kProtocolVersion;
	block->sequence.store(0, std::memory_order_relaxed);
	block->magic = kProtocolMagic;

	CoopPadState pads[kMaxPads] = {};
	pads[0].connected = 1;
	pads[0].packet = 7;
	pads[0].buttons = kButtonA | kButtonB;
	pads[0].left_trigger = 128;
	pads[0].thumb_lx = 12345;
	pads[0].thumb_ry = -4321;
	publish_pads(*block, pads, kMaxPads);

	// Load every xinput variant *before* installing hooks, so install_xinput_hooks
	// (which only hooks already-loaded modules) covers all of them and the matrix
	// below exercises each DLL's real export prologue under SafetyHook. A real game
	// loads exactly one, but which one varies by game age -- and the 32-bit crash
	// only reproduces over the specific DLL the game uses.
	const wchar_t* xinput_modules[] = {L"xinput1_4.dll", L"xinput1_3.dll", L"xinput9_1_0.dll", L"xinputuap.dll"};
	for (const wchar_t* name : xinput_modules)
	{
		LoadLibraryW(name); // best-effort; absent variants stay unloaded
	}

	// --- Hook side: connect and install over this process's own xinput. ---
	hook::IpcClient ipc;
	check(ipc.connect(10, 5), "IPC client connect");
	check(hook::install_xinput_hooks(ipc), "install XInput hooks");

	// --- Game side: query and verify we get the forwarded synthetic state. ---
	XINPUT_STATE state = {};
	check(XInputGetState(0, &state) == ERROR_SUCCESS, "slot 0 reports connected");
	check(state.dwPacketNumber == 7, "packet number forwarded");
	check(state.Gamepad.wButtons == (kButtonA | kButtonB), "buttons forwarded");
	check(state.Gamepad.bLeftTrigger == 128, "left trigger forwarded");
	check(state.Gamepad.sThumbLX == 12345, "left thumb X forwarded");
	check(state.Gamepad.sThumbRY == -4321, "right thumb Y forwarded");

	XINPUT_STATE other = {};
	check(XInputGetState(1, &other) == ERROR_DEVICE_NOT_CONNECTED, "slot 1 hidden as disconnected");

	XINPUT_CAPABILITIES caps = {};
	check(XInputGetCapabilities(0, 0, &caps) == ERROR_SUCCESS, "slot 0 capabilities reported");
	check(caps.Type == XINPUT_DEVTYPE_GAMEPAD, "capability device type");

	// Now drive every loaded variant's full export set (GetState, ordinal-100
	// GetStateEx, GetCapabilities, and the rumble SetState a game calls on a button
	// press) so each DLL's hooked prologue/trampoline is actually run.
	for (const wchar_t* name : xinput_modules)
	{
		exercise_dll(name);
	}

	// Status back-channel: the host relies on these to prove the hook is live.
	check(block->status.attached == 1, "status reports attached");
	check(block->status.get_state_calls[0].load(std::memory_order_relaxed) >= 1, "status counts slot 0 GetState");
	check(block->status.get_state_calls[1].load(std::memory_order_relaxed) >= 1, "status counts slot 1 GetState");
	check(block->status.get_caps_calls[0].load(std::memory_order_relaxed) >= 1, "status counts slot 0 GetCaps");

	// Rumble forwarding: exercise_dll called XInputSetState(0, {0x8000, 0x4000}); the
	// hook should have recorded it into the status for the host to forward to the guest.
	check(block->status.rumble_left[0] == 0x8000 && block->status.rumble_right[0] == 0x4000,
	      "status records rumble from XInputSetState");

	hook::remove_xinput_hooks();

	std::printf(g_failures == 0 ? "SELFTEST PASS\n" : "SELFTEST FAILED (%d)\n", g_failures);
	return g_failures == 0 ? 0 : 1;
}