挂钩 WH_CALLWNDPROC 后未获取窗口过程消息 [英] Not getting Window Procedure messages after hooking WH_CALLWNDPROC

问题描述

我尝试过使用全局钩子，但钩子过程只接收到我的程序线程的窗口过程消息，而针对特定应用程序(线程)的结果根本没有消息.

I've tried using a global hook but the hookprocedure only recieved window procedure messages for my program thread, and targeting a specific application (thread) results in no messages at all.

我正确地将 DLL 中的函数用于非本地挂钩.这是我的应用代码.

I'm properly using a function in a DLL for a non-local hook. Here is my app code.

#include <Windows.h>
#include <stdio.h>

HINSTANCE hinst;
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

int main() {
    HWND notepad = FindWindow(NULL, L"Untitled - Notepad");

    if (!notepad)
        return 0;

    hinst = GetModuleHandle(NULL);

    // create a window class:
    WNDCLASS wc = {};
    wc.lpfnWndProc = WindowProc;
    wc.hInstance = hinst;
    wc.lpszClassName = L"hooking";

    // register class with operating system:
    RegisterClass(&wc);

    // create and show window:
    HWND hwnd = CreateWindow(L"hooking", L"hooking", WS_OVERLAPPEDWINDOW, 0, 0, 500, 400, NULL, NULL, hinst, NULL);

    if (hwnd == NULL) {
        return 0;
    }

    ShowWindow(hwnd, SW_SHOW);

    DWORD threadID = GetWindowThreadProcessId(notepad, NULL);

    HINSTANCE hinstDLL = LoadLibrary(TEXT("..\\Debug\\ProcHookDLL.dll"));

    void (*AttachHookProc)(DWORD);
    AttachHookProc = (void (*)(DWORD)) GetProcAddress(hinstDLL, "AttachHook"); 
    AttachHookProc(threadID);

    // handle messages:
    MSG msg = {};

    while(GetMessage(&msg, hwnd, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    printf("Done execution... press any key to exit");
    char garbage = getchar();
    return 0;
}


LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
    if (uMsg == WM_DESTROY) {
        PostQuitMessage(0);
    }
    return DefWindowProc(hwnd, uMsg, wParam, lParam);
}

这是 DLL 的代码.我没有收到任何消息是什么原因?

Here is the code for the DLL. Is there a reason i'm not receiving any messages?

#include <Windows.h>
#include <stdio.h>

// TODO: create a mutex so this can only be loaded once
HMODULE thisModule;
HHOOK hook;
LRESULT CALLBACK LaunchListener(int nCode, WPARAM wParam, LPARAM lParam);

BOOL APIENTRY DllMain(HMODULE hModule, DWORD  ul_reason_for_call, LPVOID lpReserved)
{
    thisModule = hModule;

    // Very restricted set of things that can be done in DllMain, refer to documentation
    // before adding anything here.

    switch (ul_reason_for_call) {
    case DLL_PROCESS_ATTACH:
    case DLL_THREAD_ATTACH:
        break;
    case DLL_THREAD_DETACH:
    case DLL_PROCESS_DETACH:
        break;
    }
    return TRUE;
}

#ifdef __cplusplus    // If used by C++ code, 
extern "C" {          // we need to export the C interface
#endif
//window message loop is necessary for hooks to work? (didn't work with console app)
//provide function pointer to execute when notepad is launched.
__declspec(dllexport) void AttachHook(DWORD threadID) {
    hook = SetWindowsHookEx(WH_CALLWNDPROC, LaunchListener, thisModule, threadID);
}
#ifdef __cplusplus
}
#endif

LRESULT CALLBACK LaunchListener(int nCode, WPARAM wParam, LPARAM lParam) {
    // process event here
    if (nCode >= 0) {
        //wparam specifies if the message was sent by the current thread or not.
        CWPSTRUCT * cwp = (CWPSTRUCT *)lParam;
        wchar_t windowName[256];
        GetWindowText(cwp->hwnd, windowName, 256);
        wprintf(L"%#8X: %s\n", cwp->message, windowName);
        if (cwp->message == WM_CREATE) {
            __debugbreak();
            wchar_t moduleName[256];
            //cwp->hwnd
            //GetModuleFileName(0, moduleName, 256);
            GetWindowText(cwp->hwnd, moduleName, 256);
            int x = 0;
            x++;
        }
    }

    return CallNextHookEx(NULL, nCode, wParam, lParam);
}

推荐答案

没有问题，hook 安装正确.但是我不知道钩子过程是从窗口过程收到消息的进程的上下文中运行的.

There was no problem, the hook installs correctly. However I didn't know that the hook procedure runs from the context of the process whose window procedure has gotten a message.

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