[原创]捕捉 OutputDebugString 输出的字符串_outputdebugstring信息监听vc-优快云博客

[原创]捕捉 OutputDebugString 输出的字符串

在调试状态下，VC 等调试器可以捕捉程序中的 OutputDebugString 输出的信息。其实 OutputDebugString 就是往一片共享影射的内存中写入了一段数据，并创建了两个 Enevt，指明数据写入事件被触发。在非调试状态下，我们也可以通过编程实现捕捉 OutputDebugString 的输出。下面的代码演示了如何获取这些信息:

DWORD WINAPI CDebugTrack::TrackProc(PVOID pvParam)
{ 
  HANDLE hMapping = NULL;
  HANDLE hAckEvent = NULL;
  PDEBUGBUFFER pdbBuffer = NULL;
  TCHAR tzBuffer[MAX_DebugBuffer];

  _Try
  { 
    // 设置初始结果
    m_dwResult = ERROR_INVALID_HANDLE;

    // 打开事件句柄
    hAckEvent = CreateEvent(NULL, FALSE, FALSE, TEXT("DBWIN_BUFFER_READY"));
    _LeaveIf(hAckEvent == NULL);

    m_hReadyEvent = CreateEvent(NULL, FALSE, FALSE, TEXT("DBWIN_DATA_READY"));
    _LeaveIf(m_hReadyEvent == NULL);

    // 创建文件映射
    hMapping = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, MAX_DebugBuffer, TEXT("DBWIN_BUFFER"));
    _LeaveIf(hMapping == NULL);

    // 映射调试缓冲区
    pdbBuffer = (PDEBUGBUFFER) MapViewOfFile(hMapping, FILE_MAP_READ, 0, 0, 0);
    _LeaveIf(pdbBuffer == NULL);

    // 循环
    for (m_dwResult = ERROR_SIGNAL_PENDING; (m_dwResult == ERROR_SIGNAL_PENDING); )
    { 
      // 等待缓冲区数据
      SetEvent(hAckEvent);
      if (WaitForSingleObject(m_hReadyEvent, INFINITE) == WAIT_OBJECT_0)
      { 
        // 如果是继续等待，否则表示主线程发出了停止信号，退出当前线程
        if (m_dwResult == ERROR_SIGNAL_PENDING)
        { 
          // 添加新项
          _AStrToStr(tzBuffer, pdbBuffer->szString);
          CListView::AddDebugItem(tzBuffer, pdbBuffer->dwProcessId);
         }
       }
      else
      { 
        // 等待失败
        m_dwResult = WAIT_ABANDONED;
       }
     }
   }
  _Finally
  { 
    // 释放
    if (pdbBuffer)
    { 
      UnmapViewOfFile(pdbBuffer);
     }

    _SafeCloseHandle(hMapping);
    _SafeCloseHandle(m_hReadyEvent);
    _SafeCloseHandle(hAckEvent);

    PostMessage(CMainWnd::m_hWnd, WM_COMMAND, IDC_DebugTrack, m_dwResult);

    // 返回结果
    return m_dwResult;
   }
 }