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classic-maximized-windows-fix 2.0 (#447)
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- Moved global window procedure hooking to leverage the availability of the theme engine (uxtheme), rather than using SetWindowsHookEx.
- Improved compatibility with many apps, such as pre-Windows 8 versions of Task Manager.
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@ephemeralViolette
ephemeralViolette authored Dec 25, 2023
1 parent f80c31b commit a7051cb
Showing 1 changed file with 107 additions and 153 deletions.
260 changes: 107 additions & 153 deletions mods/classic-maximized-windows-fix.wh.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@
// @id classic-maximized-windows-fix
// @name Fix Classic Theme Maximized Windows
// @description Fix maximized windows having borders that spill out onto additional displays when using the classic theme.
// @version 1.2
// @version 2.0
// @author ephemeralViolette
// @github https://github.com/ephemeralViolette
// @include *
Expand All @@ -16,6 +16,8 @@
// @exclude winlogon.exe
// @exclude logonui.exe
// @exclude ApplicationFrameHost.exe
// @exclude gameinputsvc.exe
// @exclude svchost.exe

// @compilerOptions -lgdi32 -luser32
// ==/WindhawkMod==
Expand Down Expand Up @@ -46,15 +48,17 @@ so rarely they may be affected. For consistency, I manually excluded `conhost.ex
#include <vector>
#include <unordered_map>
#include <algorithm>
#include <synchapi.h>
#include <windhawk_utils.h>

// No critical section; this is only written to once and from only one thread.
bool g_instanceHasInit = false;
// Defines data shared by all instances of the library, even across processes.
#define SHARED_SECTION __attribute__((section(".shared")))
asm(".section .shared,\"dws\"\n");

CRITICAL_SECTION g_lockForAffectedWindows;
std::vector<HWND> g_affectedWindows;

CRITICAL_SECTION g_lockForAffectedThreads;
std::unordered_map<DWORD, HHOOK> g_affectedThreads;
void *g_pfnThemePostWndProc SHARED_SECTION = NULL;

// === DPI HELPERS === //
// These are only available in Windows 10, version 1607 and newer.
Expand Down Expand Up @@ -156,9 +160,9 @@ void HandleMaxForWindow(HWND hWnd, UINT uMsg)
GetSystemMetricsForWindow(hWnd, SM_CXPADDEDBORDER);

/**
* Get the info for the monitor the window is on.
* This contains rcWork, which accounts for the taskbar.
*/
* Get the info for the monitor the window is on.
* This contains rcWork, which accounts for the taskbar.
*/
HMONITOR hm = MonitorFromWindow(hWnd, MONITOR_DEFAULTTONEAREST);
MONITORINFO mi;
mi.cbSize = sizeof(MONITORINFO);
Expand Down Expand Up @@ -207,21 +211,6 @@ LRESULT WINAPI DefWindowProcW_hook(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM l
return DefWindowProcW_orig(hWnd, uMsg, wParam, lParam);
}

/*
* OnCallWndProc: Handle window procedure calls received from the hooks.
*/
LRESULT CALLBACK OnCallWndProc(int nCode, WPARAM wParam, LPARAM lParam)
{
CWPSTRUCT *params = (CWPSTRUCT *)lParam;

if (nCode < 0)
return 0;

HandleMaxForWindow(params->hwnd, params->message);

return 0;
}

/*
* InitCriticalSections: Setup data-access locks.
*/
Expand All @@ -230,9 +219,6 @@ bool InitCriticalSections()
if (!InitializeCriticalSectionAndSpinCount(&g_lockForAffectedWindows, 0x400))
return false;

if (!InitializeCriticalSectionAndSpinCount(&g_lockForAffectedThreads, 0x400))
return false;

return true;
}

Expand All @@ -242,90 +228,103 @@ bool InitCriticalSections()
void CleanCriticalSections()
{
DeleteCriticalSection(&g_lockForAffectedWindows);
DeleteCriticalSection(&g_lockForAffectedThreads);
}

/*
* InstallHookForCurrentThread: Sets up a Windows Hook for listening to application messages.
* ThemePostWndProc_hook: Leverage theme hooks being available to hook window procedures globally.
*
* Since the theme engine is available for most applications, even for the majority of classic theme
* users since Windows 8, it is possible to take advantage of one of its hooks in order to globally
* hook window procedure handling.
*
* This is used as an alternative method to knowing when a window is maximized, since it doesn't
* depend on a program calling DefWindowProc.
* To my knowledge, this will only fail for 16-bit applications (which Windhawk cannot hook anyways)
* and windows owned by certain system processes (such as CSRSS).
*/
HRESULT InstallHookForCurrentThread()
typedef BOOL (CALLBACK *ThemePostWndProc_t)(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam, LRESULT *plResult, void **ppvParam);
ThemePostWndProc_t ThemePostWndProc_orig;
BOOL CALLBACK ThemePostWndProc_hook(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam, LRESULT *plResult, void **ppvParam)
{
HRESULT hr = S_OK;
DWORD currentThreadId = GetCurrentThreadId();
Wh_Log(L"Entering critical section in thread #%d", currentThreadId);
EnterCriticalSection(&g_lockForAffectedThreads);
BOOL result = ThemePostWndProc_orig(hWnd, uMsg, wParam, lParam, plResult, ppvParam);

if (!g_affectedThreads.contains(currentThreadId))
{
HHOOK hHook = SetWindowsHookExW(
WH_CALLWNDPROC,
(HOOKPROC)OnCallWndProc,
NULL,
currentThreadId
);

if (hHook)
{
Wh_Log(
L"Installed Windows Hook #%d (%p) for thread #%d (%p)",
hHook, hHook,
currentThreadId, currentThreadId
);
g_affectedThreads.insert(
std::make_pair(currentThreadId, hHook)
);
}
else
{
hr = E_FAIL;
}
}
Wh_Log(L"Leaving critical section in thread #%d", currentThreadId);
LeaveCriticalSection(&g_lockForAffectedThreads);
HandleMaxForWindow(hWnd, uMsg);

return hr;
return result;
}

struct CMWF_SYMBOL_HOOK {
std::vector<std::wstring> symbols;
void** pOriginalFunction;
void* hookFunction = nullptr;
bool optional = false;
void **pSharedMemoryCache;
};

/*
* UninstallHooks: Uninstall all Windows Hooks for every thread.
* CmwfHookSymbols: A custom hook wrapper which allows storing symbol hook results in the
* module's shared memory for faster access.
*
* TODO: This is good for the current application, which hooks only one symbol, but it will
* be less efficient to use for multiple symbol hooks at the moment because it requeries
* each time. Please keep this in mind if you're looking to use this code for your own
* purposes.
*/
void UninstallHooks()
bool CmwfHookSymbols(
HMODULE module,
const CMWF_SYMBOL_HOOK *symbolHooks,
size_t symbolHooksCount
)
{
DWORD currentThreadId = GetCurrentThreadId();
Wh_Log(L"Entering critical section in thread #%d", currentThreadId);
EnterCriticalSection(&g_lockForAffectedThreads);

int installedHooks = g_affectedThreads.size();

for (auto &it : g_affectedThreads)
for (size_t i = 0; i < symbolHooksCount; i++)
{
HHOOK &hHook = it.second;
BOOL success = UnhookWindowsHookEx(hHook);

if (success)
installedHooks--;
}
void *address = nullptr;
if (symbolHooks[i].pSharedMemoryCache && *(symbolHooks[i].pSharedMemoryCache) != NULL)
{
address = *(symbolHooks[i].pSharedMemoryCache);
Wh_Log(
L"CmwfHookSymbols: Hooking symbol %.*s from in-memory cache.",
symbolHooks[i].symbols[0].length(),
symbolHooks[i].symbols[0].data()
);
}
else
{
address = nullptr;
WindhawkUtils::SYMBOL_HOOK proxyHook = {
symbolHooks[i].symbols,
&address,
NULL,
symbolHooks[i].optional
};

if (!WindhawkUtils::HookSymbols(module, &proxyHook, 1))
{
return false;
}

for (HWND &it : g_affectedWindows)
{
UndoWindowMasking(it);
}
if (address)
{
if (symbolHooks[i].pSharedMemoryCache && *(symbolHooks[i].pSharedMemoryCache) == NULL)
{
*(symbolHooks[i].pSharedMemoryCache) = address;
}
}
else
{
return false;
}
}

if (installedHooks == 0)
{
Wh_Log(L"Successfully uninstalled all hooks.");
g_affectedThreads.clear();
}
else
{
Wh_Log(L"Failed to uninstall %d hooks. Memory was not cleared for process.", installedHooks);
if (address != NULL)
{
Wh_SetFunctionHook(
address,
symbolHooks[i].hookFunction,
symbolHooks[i].pOriginalFunction
);
}
}

Wh_Log(L"Leaving critical section in thread #%d", currentThreadId);
LeaveCriticalSection(&g_lockForAffectedThreads);
return true;
}

// The mod is being initialized, load settings, hook functions, and do other
Expand All @@ -337,6 +336,7 @@ BOOL Wh_ModInit()
InitCriticalSections();

HMODULE user32 = LoadLibraryW(L"user32.dll");
HMODULE uxtheme = LoadLibraryW(L"uxtheme.dll");

// Init DPI helpers:
*(FARPROC *)&g_pGetDpiForWindow = GetProcAddress(user32, "GetDpiForWindow");
Expand All @@ -358,10 +358,22 @@ BOOL Wh_ModInit()
(void **)&DefWindowProcA_orig
);

// Windows hook as a workaround for some applications (i.e. Firefox):
InstallHookForCurrentThread();
CMWF_SYMBOL_HOOK symbolHooks[] = {
{
.symbols = {
#ifdef _WIN64
L"int __cdecl ThemePostWndProc(struct HWND__ *,unsigned int,unsigned __int64,__int64,__int64 *,void * *)"
#else
L"int __stdcall ThemePostWndProc(struct HWND__ *,unsigned int,unsigned int,long,long *,void * *)"
#endif
},
.pOriginalFunction = (void **)&ThemePostWndProc_orig,
.hookFunction = (void *)ThemePostWndProc_hook,
.pSharedMemoryCache = (void **)&g_pfnThemePostWndProc
}
};

g_instanceHasInit = true;
CmwfHookSymbols(uxtheme, symbolHooks, ARRAYSIZE(symbolHooks));

Wh_Log(L"Finished init");

Expand All @@ -373,63 +385,5 @@ void Wh_ModUninit()
{
Wh_Log(L"Uninit");

UninstallHooks();
CleanCriticalSections();

g_instanceHasInit = false;
}

/*
* DllMain: Listen for thread creation for hook installation.
*/
BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD fdwReason, LPVOID lpvReserved)
{
switch (fdwReason)
{
// DLL_THREAD_ATTACH: Install a Windows Hook on all incoming threads (if necessary):
case DLL_THREAD_ATTACH:
{
InstallHookForCurrentThread();
break;
}

case DLL_THREAD_DETACH:
{
DWORD currentThreadId = GetCurrentThreadId();
Wh_Log(L"Entering critical section in thread #%d", currentThreadId);
EnterCriticalSection(&g_lockForAffectedThreads);

if (g_affectedThreads.contains(currentThreadId))
{
HHOOK &hHook = g_affectedThreads.at(currentThreadId);
BOOL status = UnhookWindowsHookEx(hHook);

if (status)
{
Wh_Log(
L"Successfully detached Windows Hook #%d (%p) for thread #%d (%p)!",
hHook, hHook,
currentThreadId, currentThreadId
);

g_affectedThreads.erase(currentThreadId);
}
else
{
Wh_Log(
L"Failed to detach Windows Hook #%d (%p) for thread #%d (%p)",
hHook, hHook,
currentThreadId, currentThreadId
);
}
}

Wh_Log(L"Leaving critical section in thread #%d", currentThreadId);
LeaveCriticalSection(&g_lockForAffectedThreads);

break;
}
}

return TRUE;
}

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