Finding a 3rd party QWidget with injected code & QWidget::find(hwnd)

Question

Hey, I have a Qt Dll wich I inject into a third-party Application using windows detours library:

if(!DetourCreateProcessWithDll( Path, NULL, NULL, NULL, TRUE, 
                                CREATE_DEFAULT_ERROR_MODE | CREATE_SUSPENDED, NULL, NULL,
                                &si, &pi, "C:\\Program Files\\Microsoft Research\\Detours Express 2.1\\bin\\detoured.dll",
           "C:\\Users\\Dave\\Documents\\Visual Studio 2008\\Projects\\XOR\\Debug\\XOR.dll", NULL))

and then I set a system-wide hook to intercept window creation:

HHOOK h_hook = ::SetWindowsHookEx(WH_CBT, (HOOKPROC)CBTProc, Status::getInstance()->getXORInstance(), 0);

Where XOR is my programs name, and Status::getInstance() is a Singleton where I keep globals.

In my CBTProc callback, I want to intercept all windows that are QWidgets:

HWND hwnd= FindWindow(L"QWidget", NULL);

which works well, since I get a corresponding HWND (I checked with Spy++) Then, I want to get a pointer to the QWidget, so I can use its functions:

QWidget* q = QWidget::find(hwnd);

but here's the problem, the returned pointer is always 0. Am I not injecting my code into the process properly? Or am I not using QWidget::find() as I should?

Thanks,

Dave

EDIT:If i change the QWidget::find() function to an exported function of my DLL, after setting the hooks (so I can set and catch a breakpoint), QWidgetPrivate::mapper is NULL.

Answer 1

Compare the addresses of `QWidgetPrivate::mapper in the DLL and in your code. Esp. if one is linked statically, there might be two instance of it, each with it's own, disjoint, set of widgets.

Answer 2

Answered:

Stupid mistake, I was compiling in Debug, so it was QtGui4d.dll and QtCore4d.dll that where loading, not QtCore4.dll and QtGui.dll

Answer 3

how can i find out which dll is loaded? i have the same problem as David Menard

I'm running debug build, succesfully(??) hook dll, attach with debuger to injected application exe, but no success using QWidget::find. HWND is correct.