基于visual c++之windows核心编程代码分析（17）通过pipe进程间通信

http://tech.ddvip.com/2012-12/1355150688186856.html

管道是一种用于在进程间共享数据的机制，其实质是一段共享内存。Windows系统为这段共享的内存设计采用数据流I/0的方式来访问。由一个进程读、另一个进程写，类似于一个管道两端，因此这种进程间的通信方式称作“管道”。

   管道分为匿名管道和命名管道。

   匿名管道只能在父子进程间进行通信，不能在网络间通信，而且数据传输是单向的，只能一端写，另一端读。

   命令管道可以在任意进程间通信，通信是双向的，任意一端都可读可写，但是在同一时间只能有一端读、一端写。

管道客户端代码实现如下

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/* 头文件 */ #include <windows.h>      #include <stdio.h>     #include <conio.h>     #include <tchar.h>     /* 常量 */ #define BUFSIZE 512     /* ************************************    * int main(VOID)     * 功能    pipe 通信服务端主函数    **************************************/ int main(int argc, TCHAR *argv[])      {          HANDLE hPipe;          LPTSTR lpvMessage=TEXT("Default message from client");          TCHAR chBuf[BUFSIZE];          BOOL fSuccess;          DWORD cbRead, cbWritten, dwMode;          LPTSTR lpszPipename = TEXT("\.pipesamplenamedpipe");                     if( argc > 1 )  // 如果输入了参数，则使用输入的参数             lpvMessage = argv[1];         while(1)          {              // 打开一个命名pipe             hPipe = CreateFile(                  lpszPipename,  // pipe 名                  GENERIC_READ |   GENERIC_WRITE,    //  可读可写                 0,             // 不共享                 NULL,          // 默认安全属性                 OPEN_EXISTING, // 已经存在（由服务端创建）                 0,             // 默认属性                 NULL);                 if(hPipe != INVALID_HANDLE_VALUE)                  break;                         // 如果不是 ERROR_PIPE_BUSY 错误，直接退出               if(GetLastError() != ERROR_PIPE_BUSY)              {                 printf("Could not open pipe");                  return0;             }                        // 如果所有pipe实例都处于繁忙状态，等待2秒。             if(!WaitNamedPipe(lpszPipename, 2000))              {                  printf("Could not open pipe");                  return0;             }          }                     // pipe已经连接，设置为消息读状态          dwMode = PIPE_READMODE_MESSAGE;          fSuccess = SetNamedPipeHandleState(              hPipe,   // 句柄             &dwMode, // 新状态             NULL,    // 不设置最大缓存             NULL);   // 不设置最长时间         if(!fSuccess)          {             printf("SetNamedPipeHandleState failed");              return0;         }                    // 写入pipe         fSuccess = WriteFile(              hPipe,                 // 句柄             lpvMessage,            // 写入的内容             (lstrlen(lpvMessage)+1)*sizeof(TCHAR),// 写入内容的长度             &cbWritten,            // 实际写的内容             NULL);                 // 非 overlapped          if(!fSuccess)          {             printf("WriteFile failed");              return0;         }                    do      {              // 读回复              fSuccess = ReadFile(                  hPipe,   // 句柄                 chBuf,   // 读取内容的缓存                 BUFSIZE*sizeof(TCHAR), // 缓存大小                 &cbRead, // 实际读的字节                 NULL);   // 非 overlapped                         if(! fSuccess && GetLastError() != ERROR_MORE_DATA)                  break;//失败，退出                        _tprintf( TEXT("%sn"), chBuf );// 打印读的结果         }while (!fSuccess); //  ERROR_MORE_DATA 或者成功则循环                    getch();//任意键退出         // 关闭句柄         CloseHandle(hPipe);           return0;      }

管道服务端代码实现如下，

双击代码全选

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/* 头文件 */ #include <windows.h>      #include <stdio.h>     #include <tchar.h>     /* 常量 */ #define PIPE_TIMEOUT 5000     #define BUFSIZE 4096     /* 结构定义 */ typedef struct  {          OVERLAPPED oOverlap;          HANDLE hPipeInst;          TCHAR chRequest[BUFSIZE];          DWORD cbRead;         TCHAR chReply[BUFSIZE];          DWORD cbToWrite;      } PIPEINST, *LPPIPEINST;      /* 函数声明 */ VOID DisconnectAndClose(LPPIPEINST);      BOOL CreateAndConnectInstance(LPOVERLAPPED);      BOOL ConnectToNewClient(HANDLE, LPOVERLAPPED);      VOID GetAnswerToRequest(LPPIPEINST);      VOID WINAPI CompletedWriteRoutine(DWORD, DWORD, LPOVERLAPPED);      VOID WINAPI CompletedReadRoutine(DWORD, DWORD, LPOVERLAPPED);      /* 全局变量 */ HANDLE hPipe;      /* ************************************    * int main(VOID)     * 功能    pipe 通信服务端主函数    **************************************/ int main(VOID)      {          HANDLE hConnectEvent;          OVERLAPPED oConnect;          LPPIPEINST lpPipeInst;          DWORD dwWait, cbRet;          BOOL fSuccess, fPendingIO;                     // 用于连接操作的事件对象          hConnectEvent = CreateEvent(              NULL,   // 默认属性             TRUE,   // 手工reset             TRUE,   // 初始状态 signaled              NULL);  // 未命名                    if(hConnectEvent == NULL)          {             printf("CreateEvent failed with %d.n", GetLastError());              return0;         }         // OVERLAPPED 事件         oConnect.hEvent = hConnectEvent;                     // 创建连接实例，等待连接         fPendingIO = CreateAndConnectInstance(&oConnect);                     while(1)          {             // 等待客户端连接或读写操作完成              dwWait = WaitForSingleObjectEx(                  hConnectEvent, // 等待的事件                  INFINITE,      // 无限等待                 TRUE);                               switch(dwWait)              {              case0:                      // pending                  if(fPendingIO)                  {                      // 获取 Overlapped I/O 的结果                     fSuccess = GetOverlappedResult(                          hPipe,    // pipe 句柄                          &oConnect,// OVERLAPPED 结构                          &cbRet,   // 已经传送的数据量                         FALSE);   // 不等待                     if(!fSuccess)                      {                         printf("ConnectNamedPipe (%d)n", GetLastError());                          return0;                     }                 }                             // 分配内存                  lpPipeInst = (LPPIPEINST) HeapAlloc(GetProcessHeap(),0,sizeof(PIPEINST));                  if(lpPipeInst == NULL)                  {                     printf("GlobalAlloc failed (%d)n", GetLastError());                      return0;                 }                 lpPipeInst->hPipeInst = hPipe;                             // 读和写，注意CompletedWriteRoutine和CompletedReadRoutine的相互调用                 lpPipeInst->cbToWrite = 0;                  CompletedWriteRoutine(0, 0, (LPOVERLAPPED) lpPipeInst);                             // 再创建一个连接实例，以响应下一个客户端的连接                 fPendingIO = CreateAndConnectInstance(                      &oConnect);                  break;                             // 读写完成              caseWAIT_IO_COMPLETION:                  break;                         default:                  {                     printf("WaitForSingleObjectEx (%d)n", GetLastError());                      return0;                 }             }          }          return0;      }                 /* ************************************    * CompletedWriteRoutine     *   写入pipe操作的完成函数    *   接口参见FileIOCompletionRoutine回调函数定义    *    *   当写操作完成时被调用，开始读另外一个客户端的请求    **************************************/ VOID WINAPI CompletedWriteRoutine(                                       DWORD dwErr,                                        DWORD cbWritten,                                        LPOVERLAPPED lpOverLap)      {          LPPIPEINST lpPipeInst;          BOOL fRead = FALSE;          // 保存overlap实例         lpPipeInst = (LPPIPEINST) lpOverLap;                 // 如果没有错误         if((dwErr == 0) && (cbWritten == lpPipeInst->cbToWrite))          {                    fRead = ReadFileEx(              lpPipeInst->hPipeInst,              lpPipeInst->chRequest,              BUFSIZE*sizeof(TCHAR),              (LPOVERLAPPED) lpPipeInst,              // 写读操作完成后，调用CompletedReadRoutine             (LPOVERLAPPED_COMPLETION_ROUTINE) CompletedReadRoutine);          }            if(! fRead)              // 出错，断开连接             DisconnectAndClose(lpPipeInst);      }                 /* ************************************    * CompletedReadRoutine     *   读取pipe操作的完成函数    *   接口参见FileIOCompletionRoutine回调函数定义    *    *   当读操作完成时被调用，写入回复    **************************************/ VOID WINAPI CompletedReadRoutine(                                      DWORD dwErr,                                       DWORD cbBytesRead,                                       LPOVERLAPPED lpOverLap)      {          LPPIPEINST lpPipeInst;          BOOL fWrite = FALSE;                     // 保存overlap实例         lpPipeInst = (LPPIPEINST) lpOverLap;                     // 如果没有错误         if((dwErr == 0) && (cbBytesRead != 0))          {              // 根据客户端的请求，生成回复             GetAnswerToRequest(lpPipeInst);              // 将回复写入到pipe             fWrite = WriteFileEx(                  lpPipeInst->hPipeInst,                  lpPipeInst->chReply,//将响应写入pipe                 lpPipeInst->cbToWrite,                  (LPOVERLAPPED) lpPipeInst,                  // 写入完成后，调用CompletedWriteRoutine                 (LPOVERLAPPED_COMPLETION_ROUTINE) CompletedWriteRoutine);          }                     if(! fWrite)              // 出错，断开连接             DisconnectAndClose(lpPipeInst);      }                 /* ************************************    * VOID DisconnectAndClose(LPPIPEINST lpPipeInst)     * 功能    断开一个连接的实例    * 参数    lpPipeInst，断开并关闭的实例句柄    **************************************/ VOID DisconnectAndClose(LPPIPEINST lpPipeInst)      {          // 关闭连接实例         if(! DisconnectNamedPipe(lpPipeInst->hPipeInst) )          {             printf("DisconnectNamedPipe failed with %d.n", GetLastError());         }         // 关闭 pipe 实例的句柄          CloseHandle(lpPipeInst->hPipeInst);          // 释放         if(lpPipeInst != NULL)              HeapFree(GetProcessHeap(),0, lpPipeInst);      }                 /* ************************************    * BOOL CreateAndConnectInstance(LPOVERLAPPED lpoOverlap)    * 功能    建立连接实例    * 参数    lpoOverlap，用于overlapped IO的结构    * 返回值   是否成功    **************************************/ BOOL CreateAndConnectInstance(LPOVERLAPPED lpoOverlap)      {          LPTSTR lpszPipename = TEXT("\.pipesamplenamedpipe");          // 创建named pipe           hPipe = CreateNamedPipe(              lpszPipename,            // pipe 名              PIPE_ACCESS_DUPLEX |     // 可读可写             FILE_FLAG_OVERLAPPED,    // overlapped 模式              // pipe模式             PIPE_TYPE_MESSAGE |      // 消息类型 pipe              PIPE_READMODE_MESSAGE |  // 消息读模式              PIPE_WAIT,               // 阻塞模式             PIPE_UNLIMITED_INSTANCES,// 无限制实例             BUFSIZE*sizeof(TCHAR),   // 输出缓存大小             BUFSIZE*sizeof(TCHAR),   // 输入缓存大小             PIPE_TIMEOUT,            // 客户端超时             NULL);                   // 默认安全属性         if(hPipe == INVALID_HANDLE_VALUE)          {             printf("CreateNamedPipe failed with %d.n", GetLastError());              return0;         }                    // 连接到新的客户端         returnConnectToNewClient(hPipe, lpoOverlap);      }                /* ************************************    * BOOL ConnectToNewClient(HANDLE hPipe, LPOVERLAPPED lpo)    * 功能    建立连接实例    * 参数    lpoOverlap，用于overlapped IO的结构    * 返回值   是否成功    **************************************/ BOOL ConnectToNewClient(HANDLE hPipe, LPOVERLAPPED lpo)      {          BOOL fConnected, fPendingIO = FALSE;                     // 开始一个 overlapped 连接          fConnected = ConnectNamedPipe(hPipe, lpo);                     if(fConnected)          {             printf("ConnectNamedPipe failed with %d.n", GetLastError());              return0;         }         switch(GetLastError())          {              // overlapped连接进行中.          caseERROR_IO_PENDING:              fPendingIO = TRUE;              break;              // 已经连接，因此Event未置位          caseERROR_PIPE_CONNECTED:              if(SetEvent(lpo->hEvent))                  break;              // error         default:              {                 printf("ConnectNamedPipe failed with %d.n", GetLastError());                 return0;             }         }          returnfPendingIO;      }                // TODO根据客户端的请求，给出响应     VOID GetAnswerToRequest(LPPIPEINST pipe)     {         _tprintf( TEXT("[%d] %sn"), pipe->hPipeInst, pipe->chRequest);         lstrcpyn( pipe->chReply,  TEXT("Default answer from server") ,BUFSIZE);         pipe->cbToWrite = (lstrlen(pipe->chReply)+1)*sizeof(TCHAR);     }