将 CALLBACK 从 dll 传递到 EXE

Question

我有一个 DLL，用来挂接记事本并捕获击键。一切正常，但我想从我的 exe 中访问 KeyboardHook 回调。这样，每次触发 .dll 中的回调时，它都会将其值传递给 .exe 这可能吗？

** HOOK.dll (hookDll.cpp) **

#include "windows.h"

#pragma data_seg (".SHARED")  
     HHOOK keyboardHook = 0;  
     HINSTANCE g_hInstance = 0;  
#pragma data_seg()  

#pragma comment(linker, "/SECTION:.SHARED,RWS")

extern "C" __declspec(dllexport) LRESULT CALLBACK KeyboardHook(int nCode, WPARAM wParam, LPARAM lParam)
{
    if(0 > nCode)
    return CallNextHookEx(keyboardHook, nCode, wParam, lParam);

    {
        MessageBox(NULL, L"Got Keyboard Event !", L"Event", 0);
    }

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

extern "C" __declspec(dllexport) bool InstallKeyboardHook(unsigned long threadID)
{
    keyboardHook = SetWindowsHookEx(WH_KEYBOARD, &KeyboardHook, g_hInstance, threadID);
    return true;
}

extern "C" __declspec(dllexport) bool UnInstallKeyboardHook()
{
    UnhookWindowsHookEx(keyboardHook);  
    return true;
}

BOOL APIENTRY DllMain( HMODULE hModule, DWORD  ul_reason_for_call, LPVOID lpReserved ) 
{     
switch (ul_reason_for_call){
    case DLL_PROCESS_ATTACH:
        g_hInstance  = (HINSTANCE) hModule;
        break;
    case DLL_THREAD_ATTACH:
    case DLL_THREAD_DETACH:
    case DLL_PROCESS_DETACH:
        break;
}     
return TRUE; 
}

** Hook.exe (hook.h) **

#pragma once

#include "afxwin.h"

typedef bool(*InstallHook)(unsigned long);
typedef bool(*UnInstallHook)();
typedef LRESULT (*KeyboardHook)(int nCode, WPARAM wParam, LPARAM lParam);

LRESULT CALLBACK MyCallback(int nCode, WPARAM wParam, LPARAM lParam)
{
    //Id like this to get called whenever the CALLBACK in the dll is called
    MessageBox(NULL, L"test", L"test", 0);
    return NULL;
}


class CTrayMeApp : public CWinApp
{
public:
CTrayMeApp(){};
~CTrayMeApp(){};

virtual BOOL InitInstance();
};

extern CTrayMeApp theApp;

** Hook.exe (hook.cpp) **

#include "hook.h"

CTrayMeApp theApp;

BOOL CTrayMeApp::InitInstance()
{
BOOL bReturn = FALSE;

CWinApp::InitInstance();

HMODULE hModule = LoadLibrary(_T("Hook.dll"));

//Get the function address which installs the keyboard events filter.
InstallHook fpKeyboardHook = (InstallHook) GetProcAddress(hModule,"InstallKeyboardHook");

//Install the Keyboard Event Hook (Filter).
fpKeyboardHook(GetTargetThreadIdFromWindow("Notepad", "Untitled - Notepad"));

//Install the Callback
KeyboardHook cpKeyboardHook = (KeyboardHook) GetProcAddress(hModule,"_KeyboardHook@12");

//OK, are callback is here, now how do we make use of it?
KeyboardHook(MyCallback); //of course this won't work, but it gives an idea of what I'm trying to do.

FreeLibrary(hModule);

Sleep(10000); //give us 10 seconds to test it out
return bReturn;
}

Answer 1

在 DLL 内部：

LRESULT CALLBACK (*myCallbackRef)(int nCode, WPARAM wParam, LPARAM lParam);

extern "C" __declspec(dllexport) void InstallMyHook(LRESULT CALLBACK (*MyCallback)(int nCode, WPARAM wParam, LPARAM lParam))
{
   myCallbackRef = MyCallback;
}

使用 myCallbackRef 以及 KeyboardHook 内的参数。

在你的程序中
称呼

InstallMyHook(MyCallBack);