Question

我是一名C ++初学者（3-4个月），我正试图依靠Windows挂钩。我有一个DLL的错误，我正在尝试注入，一段时间后，我意识到我的DllMain没有被调用！我查看了StackOverflow上的几乎所有线程，无法弄清楚我的问题。我发现通过将变量初始化为5，在DllMain中将其更改为1并在函数中输出变量。变量永远不会改变。这是代码：

int i = 5;

BOOL APIENTRY DllMain( HANDLE hModule, DWORD  ul_reason_for_call, LPVOID lpReserved  )
{
    i=1;
    switch (ul_reason_for_call)
    {
    case DLL_PROCESS_ATTACH:
        hDll  = (HINSTANCE) hModule;

        break;

    case DLL_THREAD_ATTACH:  break;
    case DLL_THREAD_DETACH:  break;
    case DLL_PROCESS_DETACH:  break;

    }

    return TRUE;
}

bool InstallHook(){
    cout << "INSTALLING HOOK... " << endl;
    cout << i << endl;
    hHook = SetWindowsHookEx(WH_CBT, (HOOKPROC) CBTProc, hDll, 0);
    return hHook != NULL;
}

这是我加载DLL ...

typedef bool (*InstallHook)();
typedef void (*UninstallHook)();
InstallHook ih;
UninstallHook uh;
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch(msg)
    {
        case WM_CLOSE:
            DestroyWindow(hwnd);
        break;
        case WM_DESTROY:
            uh();
            PostQuitMessage(0);
        break;
        default:
            return DefWindowProc(hwnd, msg, wParam, lParam);
    }
    return 0;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    LPSTR lpCmdLine, int nCmdShow)
{
    // Bunch of code to initialize a simple window until this: 
    HINSTANCE hDll = LoadLibrary("e:\\projects\\DLL\\ToInject.dll");
    ih = (InstallHook)GetProcAddress(hDll, "InstallHook");
    uh = (UninstallHook)GetProcAddress(hDll, "UninstallHook");
    if (!ih()){
        cout << "SUCCESS" << endl;
    }else{
        cout << "FAILED" << endl;
    }
    // other stuff to create a window
    return Msg.wParam;
}

输出：

INSTALLING HOOK... 
5 // We can see here that the DLL never changed the value of i to 1.
SUCCESS
UNINSTALL HOOK...

Answer 1

按照以下步骤制作一个工作示例（这是针对visual studio）：

创建新的控制台应用程序;
检查Dll;
将其放在dllmain.cpp中：

的 dllmain.cpp 的

// dllmain.cpp : Defines the entry point for the DLL application. #include "stdafx.h" #include <string> std::string test = "not Loaded"; BOOL APIENTRY DllMain( HMODULE hModule, DWORD ul_reason_for_call, LPVOID lpReserved ) { test = "loaded"; //You also change on this location the value of a variable switch (ul_reason_for_call) { case DLL_PROCESS_ATTACH: MessageBoxA(NULL,"test","test",NULL); break; case DLL_THREAD_ATTACH: case DLL_THREAD_DETACH: case DLL_PROCESS_DETACH: break; } return TRUE; } extern "C" __declspec (dllexport) bool example() { MessageBoxA(NULL,test.c_str(),"test",NULL); return true; }

编译代码，确保它处于发布模式;

创建新的控制台应用程序;

检查空项目;

创建一个名为main.cpp;
的新文件
将其复制到文件中：

的 Main.cpp的 的

#include <windows.h> typedef bool (*testFunction)(); testFunction dllFunction; int main() { HINSTANCE hDll = LoadLibraryA("example.dll"); if(hDll) { dllFunction = (testFunction)GetProcAddress(hDll, "example"); dllFunction(); } return 0; }

构建项目，确保它处于发布模式;

从控制台应用程序中复制您在release文件夹中创建的DLL;

运行程序。

它在这里工作。我得到一个带有测试的MessageBox和一次加载。您可以将此代码与您的代码进行比较。我希望你能找到问题。

Answer 2

我在同一个程序中看到WinMain和cout。请解释您已创建的项目类型。

你可以看看这里的钩子示例 - http://www.codeproject.com/Articles/5002/Mousey-Roll-Over-and-Park

Answer 3

// Create consts for firewall types.
const int NET_FW_PROFILE2_DOMAIN = 1;
const int NET_FW_PROFILE2_PRIVATE = 2;
const int NET_FW_PROFILE2_PUBLIC = 4;

// Create the firewall type.
Type FWManagerType = Type.GetTypeFromProgID("HNetCfg.FwPolicy2");

// Use the firewall type to create a firewall manager object.
dynamic FWManager = Activator.CreateInstance(FWManagerType);

// Get the firewall settings.
bool CheckDomain =
    FWManager.FirewallEnabled(NET_FW_PROFILE2_DOMAIN);
bool CheckPrivate =
    FWManager.FirewallEnabled(NET_FW_PROFILE2_PRIVATE);
bool CheckPublic =
    FWManager.FirewallEnabled(NET_FW_PROFILE2_PUBLIC);

如果您使用C ++编译它，则必须添加＆＃34; extern＆＃34; C＆＃34; ＆＃34;在DllMain功能中

使用LoadLibrary后没有调用DllMain

3 个答案: