Question

我尝试使用Detour库挂钩CreateThread（）功能。但由于一些错误，它不会起作用。最后只调用CreateThread函数而不是直接调用，我构造自己的DLL。在DLL构造和程序编译期间。它不会返回任何错误。但是，在运行它的停止时。

testdll.cpp

#include <windows.h>

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

extern "C" _declspec(dllexport) bool _stdcall C_thread(LPSECURITY_ATTRIBUTES lpThreadAttributes,SIZE_T dwStackSize,LPTHREAD_START_ROUTINE lpStartAddress,LPVOID lpParameter,DWORD dwCreationFlags,LPDWORD lpThreadId)
{
    HANDLE hThread;
    DWORD threadID;
    hThread = CreateThread(lpThreadAttributes,dwStackSize,lpStartAddress,lpParameter,dwCreationFlags,lpThreadId);
    return hThread;
}

通过使用上面的testdll.cpp，我正在构建DLL。

cl / nologo / W3 / Ox / Zi / MD / LD test.cpp

link / DEBUG / SUBSYSTEM：WINDOWS / ENTRY：DllMain /OUT:testdll_temp.dll /DEF:test.def testdll_temp.obj kernel32.lib

testcall.cpp // *主程序* //

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

DWORD WINAPI ThreadFun(LPVOID param)
{
    printf("hi");
    return 0;
}

int main()
{
    HANDLE h;   
    DWORD threadID;
    typedef bool (_stdcall *CALL_A)(LPSECURITY_ATTRIBUTES lpThreadAttributes,SIZE_T dwStackSize,LPTHREAD_START_ROUTINE lpStartAddress,LPVOID lpParameter,DWORD dwCreationFlags,LPDWORD lpThreadId);
    printf("Creating Handle");
    HINSTANCE hinstDLL;
    BOOL fFreeDLL;

    printf("\nLoading library test.dll .... ");

    hinstDLL = LoadLibrary("testdll.dll");
    if (hinstDLL != NULL)
    {
        printf("\nLibrary loaded\n");
        CALL_A C_thread;
        C_thread = (CALL_A)GetProcAddress(hinstDLL,"C_thread"); 
        if (C_thread != NULL)
        {
            printf("lets see, it calling");
            HANDLE a = C_thread(NULL, 0, ThreadFu, NULL, 0, &threadID);
            printf("working");
        }
        else
        {
            printf("Address not found ");
        }
        fFreeDLL = FreeLibrary(hinstDLL);
    }    
    else
        printf("Library not found");
    return 0;
}

即使我编译了这个， cl / Zi testcall.cpp

但是我运行了testcall.exe文件。库已正确加载，但在执行下线时，它停止了。

HANDLE a = C_thread（NULL，0，ThreadFu，NULL，0，＆amp; threadID）;

我正在使用Visual-C ++命令提示符（不是GUI）。请帮我解决这个问题。如果有的话，请指正。

Answer 1

您的程序有未定义的行为。创建线程时，无法保证它立即运行。即使它立即运行，您在线程中FreeLibrary和printf的运行时调用之间也存在竞争条件。

您的主线程必须等到辅助线程终止：

    CALL_A C_thread;
    C_thread = (CALL_A)GetProcAddress(hinstDLL,"C_thread"); 

    if (C_thread != NULL)
    {
        printf("lets see, it calling");
        HANDLE a = C_thread(NULL, 0, ThreadFu, NULL, 0, &threadID);
        printf("working");

        if (WaitForSingleObject(a, some_time_or_infinite) != WAIT_OBJECT_0)
        {
            // this is dirty since the thread has probable no chance to release resources.
            TerminateThread(hThread);
        }
    }
    else
    {
        printf("Address not found ");
    }

    fFreeDLL = FreeLibrary(hinstDLL);

我如何解决此运行时错误？

1 个答案: