c++ - C/C++ 函数中的 LoadLibrary 和 GetProcAddress

Question

我有这个代码:

int main(int argc, char *argv[])
{
    typedef HHOOK(__stdcall *f_funci)(int, HOOKPROC, HINSTANCE, DWORD);
    HINSTANCE hGetProcIDDLL = LoadLibrary(L"User32.dll");

    if (!hGetProcIDDLL) {
        printf("could not load the dynamic library");
        printf("%d", GetLastError());
        return EXIT_FAILURE;
    }

    // resolve function address here
    f_funci SetWindowsHookEx2 = (f_funci)GetProcAddress(hGetProcIDDLL, "SetWindowsHookExW");
    if (!SetWindowsHookEx2) {
        printf("could not locate the function SetWindowsHookExW");
        printf("%d", GetLastError());
        return EXIT_FAILURE;
    }

    hMouseHook = SetWindowsHookEx2(WH_MOUSE_LL, my_function, hInstance, NULL);

    return 0;
}

如何将所有这些代码插入到函数中，然后从主函数中调用它来获取 SetWindoesHookEx2 并稍后使用它？

这里的问题是，返回的值是 typedef HHOOK(__stdcall *f_funci)(int, HOOKPROC, HINSTANCE, DWORD) 并且它是一个 HHOOK 结构，我不知道如何处理。

在简历中我想要这样的东西:

int main(void) {
    SetWindowsHook2 = dynamyc_function("User32.dll", "SetWindowsHookExW", int, HOOKPROC, HINSTANCE, DWORD)
    hMouseHook = SetWindowsHookEx2(WH_MOUSE_LL, my_function, hInstance, NULL);
    return 0;
}

我做不到:

HHOOK load_hook(){
    typedef HHOOK(__stdcall *f_funci)(int, HOOKPROC, HINSTANCE, DWORD);
    HINSTANCE hGetProcIDDLL = LoadLibrary(L"User32.dll");

    if (!hGetProcIDDLL) {
        printf("could not load the dynamic library");
        printf("%d", GetLastError());
        return EXIT_FAILURE;
    }

    // resolve function address here
    f_funci SetWindowsHookEx2 = (f_funci)GetProcAddress(hGetProcIDDLL, "SetWindowsHookExW");
    if (!SetWindowsHookEx2) {
        printf("could not locate the function SetWindowsHookExW");
        printf("%d", GetLastError());
        return EXIT_FAILURE;

    }
    return SetWindowsHookEx2;
}

有两个错误:'return':无法从 'int' 转换为 'HHOOK' 和 'return':无法从 'f_funci' 转换为 'HHOOK' > 第一个引用return EXIT_FAILURE;，第二个引用“return SetWindowsHookEx2;”

谢谢。

Answer 1

尝试这样的事情:

#include <map>
#include <string>

std::map<std::wstring, HINSTANCE> libs;

template<typename T>
bool dynamyc_function(LPCWSTR libname, LPCSTR funcname, T *func)
{
    HINSTANCE hlib = libs[libname];
    if (!hlib)
    {
        hlib = LoadLibraryW(libname);
        if (!hlib)
        {
            wprintf(L"could not load the dynamic library %s! %d", libname, GetLastError());
            return false;
        }
        libs[libname] = hlib;
    }

    *func = (T) GetProcAddress(hlib, funcname);
    if (!*func)
    {
        printf("could not locate the function %s! %d", name, GetLastError());
        return false;
    }

    return true;
}

int main(int argc, char *argv[])
{
    typedef HHOOK(__stdcall *f_funci)(int, HOOKPROC, HINSTANCE, DWORD);

    // resolve function address here
    f_funci SetWindowsHookEx2;
    if (!dynamyc_function(L"User32.dll", "SetWindowsHookExW", &SetWindowsHookEx2))
        return EXIT_FAILURE;

    HHOOK hMouseHook = SetWindowsHookEx2(WH_MOUSE_LL, my_function, hInstance, NULL);
    if (!hMouseHook)
    {
        printf("could not set hook! %d", GetLastError());
        return EXIT_FAILURE;
    }
    ...
    UnhookWindowsHookEx(hMouseHook);

    return 0;
}

或者，如果您只对特定功能感兴趣，您可以尝试这样的方法:

typedef HHOOK(__stdcall *f_funci)(int, HOOKPROC, HINSTANCE, DWORD);

HHOOK __stdcall Impl_SetWindowsHookExW(int idHook, HOOKPROC lpfn, HINSTANCE hMod, DWORD dwThreadId);
HHOOK __stdcall Stub_SetWindowsHookExW(int idHook, HOOKPROC lpfn, HINSTANCE hMod, DWORD dwThreadId);
f_funci lpSetWindowsHookExW = &Stub_SetWindowsHookExW;

HHOOK __stdcall Impl_SetWindowsHookExW(int idHook, HOOKPROC lpfn, HINSTANCE hMod, DWORD 
{
    SetLastError(ERROR_CALL_NOT_IMPLEMENTED);
    return NULL;
}

HINSTANCE hUser32 = NULL;
HHOOK __stdcall Stub_SetWindowsHookExW(int idHook, HOOKPROC lpfn, HINSTANCE hMod, DWORD dwThreadId)
{
    if (!hUser32)
    {
        hUser32 = LoadLibraryW("User32.dll");
        if (!hUser32)
        {
            DWORD err = GetLastError();
            printf("could not load the dynamic library! %d", err);
            SetLastError(err);
            return NULL;
        }
    }

    f_funci func = (f_funci) GetProcAddress(hUser32, "SetWindowsHookExW");
    if (!func)
    {
        DWORD err = GetLastError();
        printf("could not locate the function! %d", err);
        SetLastError(err);
        func = &Impl_SetWindowsHookExW;
    }

    lpSetWindowsHookExW = func;
    return func(idHook, lpfn, hMod, dwThreadId);
}

int main(int argc, char *argv[])
{
    HHOOK hMouseHook = lpSetWindowsHookExW(WH_MOUSE_LL, my_function, hInstance, NULL);
    if (!hMouseHook)
    {
        printf("could not set hook! %d", GetLastError());
        return EXIT_FAILURE;
    }
    ...
    UnhookWindowsHookEx(hMouseHook);

    return 0;
}