調用GetProcAddress時出現錯誤127

Question

我正在爲WH_GETMESSAGE寫入全局鉤子。但是，當從dll調用GetProcAddress函數時，我得到錯誤代碼127，即ERROR_PROC_NOT_FOUND。它無法找到GetMsgProc。任何想法爲什麼？

此外，我是這種編程的新手，所以對任何錯誤都不抱歉。

DLL文件：

#include "windows.h" 
#include <stdio.h> 

BOOL APIENTRY DllMain(HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved) 
{ 
    return TRUE; 
} 

__declspec(dllexport) LRESULT CALLBACK GetMsgProc(int nCode, WPARAM wParam, LPARAM lParam) 
{ 
    MessageBox(NULL, TEXT("I am in"),TEXT("In a DLL"), MB_OK); 

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

程序加載的DLL文件：

#include <windows.h> 
#include <tchar.h> 
#include <stdio.h> 

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

int main() 
{ 
    HMODULE hDll = LoadLibrary(_T("../../dllTouchInputHook/x64/Debug/dllTouchInputHook.dll")); 
    LPGetMsgProc proc = (LPGetMsgProc)GetProcAddress(hDll, "GetMsgProc"); 
    if (proc == NULL) { 
     printf("The error code is %d", GetLastError()); 
    } 

    HHOOK hMsgHook = SetWindowsHookEx(WH_GETMESSAGE, proc, hDll, 0); 

    MSG msg; 
    while (GetMessage(&msg, NULL, 0, 0) > 0) { 

     TranslateMessage(&msg); 
     DispatchMessage(&msg); 
    } 

    UnhookWindowsHookEx(hMsgHook); 

    return 0; 
} 

Answer 1

的功能沒有被發現，因爲像你期望它不被導出爲"GetMsgProc"。它實際上更像"_GetMsgProc@12"（32位）或"_GetMsgProc@20"（64位）。如果您希望導出爲"GetMsgProc"，那麼在編譯DLL時需要使用.DEF文件。

你不應該以這種方式實施鉤子開始。你應該將呼叫轉移到SetWindowsHookEx() DLL本身裏面，然後導出函數來調用它，例如：

#include "windows.h" 
#include <stdio.h> 

HINSTANCE hThisDLL; 
HHOOK hMsgHook; 

BOOL APIENTRY DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved) 
{ 
    hThisDLL = hinstDLL; 
    return TRUE; 
} 

LRESULT CALLBACK GetMsgProc(int nCode, WPARAM wParam, LPARAM lParam) 
{ 
    MessageBox(NULL, TEXT("I am in"), TEXT("In a DLL"), MB_OK); 
    return CallNextHookEx(NULL, nCode, wParam, lParam); 
} 

__declspec(dllexport) BOOL WINAPI InstallHook() 
{ 
    if (!hMsgHook) 
     hMsgHook = SetWindowsHookEx(WH_GETMESSAGE, &GetMsgProc, hThisDll, 0); 
    return (hMsgHook != NULL); 
} 

__declspec(dllexport) VOID WINAPI UninstallHook() 
{ 
    if (hMsgHook) 
    { 
     UnhookWindowsHookEx(hMsgHook); 
     hMsgHook = NULL; 
    } 
} 

#include <windows.h> 
#include <tchar.h> 
#include <stdio.h> 

typedef BOOL (WINAPI *LPInstallHook)(); 
typedef VOID (WINAPI *LPUninstallHook)(); 

int main() 
{ 
    HMODULE hDll = LoadLibrary(_T("../../dllTouchInputHook/x64/Debug/dllTouchInputHook.dll")); 
    if (!hDll) 
    { 
     printf("The error code is %d", GetLastError()); 
     return -1; 
    } 

    LPInstallHook installProc = (LPInstallHook) GetProcAddress(hDll, "InstallHook"); // or "_InstallHook" 
    LPUninstallHook uninstallProc = (installProc) ? (LPUninstallHook) GetProcAddress(hDll, "UninstallHook") : NULL; // or "_UninstallHook" 

    if (!(installProc && uninstallProc)) 
    { 
     printf("The error code is %d", GetLastError()); 
     FreeLibrary(hDll); 
     return -1; 
    } 

    if (!installProc()) 
    { 
     printf("The error code is %d", GetLastError()); 
     FreeLibrary(hDll); 
     return -1; 
    } 

    MSG msg; 
    while (GetMessage(&msg, NULL, 0, 0) > 0) { 
     TranslateMessage(&msg); 
     DispatchMessage(&msg); 
    } 

    uninstallProc(); 

    FreeLibrary(hDll); 

    return 0; 
}