GSOAP服务卡住？

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字数统计: 904 字 | 阅读时长 ≈ 4 分钟

很久以前参考了https://www.genivia.com/doc/soapdoc2.html 中的一段：How to Create a Multi-Threaded Stand-Alone Service 完成了一个简单多线程服务器的编写。但是一直以来服务器运行一段时间，接收一定量的请求后，就会出现服务器再也不返回的情况。怀疑过是不是socket数量不够用了，后来跟踪发现还能正常listen。怀疑是不是工作线程异常退出了，补充了所需的日志，也没有。后来查询到，有人曾经也问过这个问题：https://sourceforge.net/p/gsoap2/bugs/844/ 在gsoap的代码中加入日志，确实是在soap_serve卡住了，而卡住的位置就是在recv函数，位于文件stdsoap2.cpp的933行（72行）：

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frecv(struct soap *soap, char *s, size_t n)
{ register int r;
  register int retries = 100; /* max 100 retries with non-blocking sockets */
  soap->errnum = 0;
#if defined(__cplusplus) && !defined(WITH_LEAN) && !defined(WITH_COMPAT)
  if (soap->is)
  { if (soap->is->good())
      return soap->is->read(s, (std::streamsize)n).gcount();
    return 0;
  }
#endif
  if (soap_valid_socket(soap->socket))
  { for (;;)
    {
#ifdef WITH_OPENSSL
      register int err = 0;
#endif
#ifdef WITH_OPENSSL
      if (soap->recv_timeout && !soap->ssl) /* SSL: sockets are nonblocking */
#else
      if (soap->recv_timeout)
#endif
      { for (;;)
        { r = tcp_select(soap, soap->socket, SOAP_TCP_SELECT_RCV | SOAP_TCP_SELECT_ERR, soap->recv_timeout);
          if (r > 0)
            break;
          if (!r)
            return 0;
          r = soap->errnum;
          if (r != SOAP_EINTR && r != SOAP_EAGAIN && r != SOAP_EWOULDBLOCK)
            return 0;
        }
      }
#ifdef WITH_OPENSSL
      if (soap->ssl)
      { r = SSL_read(soap->ssl, s, (int)n);
        if (r > 0)
          return (size_t)r;
        err = SSL_get_error(soap->ssl, r);
        if (err != SSL_ERROR_NONE && err != SSL_ERROR_WANT_READ && err != SSL_ERROR_WANT_WRITE)
          return 0;
      }
      else if (soap->bio)
      { r = BIO_read(soap->bio, s, (int)n);
        if (r > 0)
          return (size_t)r;
        return 0;
      }
      else
#endif
#ifdef WITH_GNUTLS
      if (soap->session)
      { r = (int)gnutls_record_recv(soap->session, s, n);
        if (r >= 0)
          return (size_t)r;
      }
      else
#endif
      {
#ifndef WITH_LEAN
        if ((soap->omode & SOAP_IO_UDP))
        { SOAP_SOCKLEN_T k = (SOAP_SOCKLEN_T)sizeof(soap->peer);
          memset((void*)&soap->peer, 0, sizeof(soap->peer));
          r = recvfrom(soap->socket, s, (SOAP_WINSOCKINT)n, soap->socket_flags, (struct sockaddr*)&soap->peer, &k);	/* portability note: see SOAP_SOCKLEN_T definition in stdsoap2.h */
          soap->peerlen = (size_t)k;
#ifndef WITH_IPV6
          soap->ip = ntohl(soap->peer.sin_addr.s_addr);
#endif
        }
        else
#endif
          r = recv(soap->socket, s, (int)n, soap->socket_flags);
#ifdef PALM
        /* CycleSyncDisplay(curStatusMsg); */
#endif
        if (r >= 0)
          return (size_t)r;
        r = soap_socket_errno(soap->socket);
        if (r != SOAP_EINTR && r != SOAP_EAGAIN && r != SOAP_EWOULDBLOCK)
        { soap->errnum = r;
          return 0;
        }
      }
#if defined(WITH_OPENSSL)
      if (soap->ssl && err == SSL_ERROR_WANT_WRITE)
         r = tcp_select(soap, soap->socket, SOAP_TCP_SELECT_SND | SOAP_TCP_SELECT_ERR, soap->recv_timeout ? soap->recv_timeout : 5);
      else
#elif defined(WITH_GNUTLS)
      if (soap->session && gnutls_record_get_direction(soap->session))
         r = tcp_select(soap, soap->socket, SOAP_TCP_SELECT_SND | SOAP_TCP_SELECT_ERR, soap->recv_timeout ? soap->recv_timeout : 5);
      else
#endif
        r = tcp_select(soap, soap->socket, SOAP_TCP_SELECT_RCV | SOAP_TCP_SELECT_ERR, soap->recv_timeout ? soap->recv_timeout : 5);
      if (!r && soap->recv_timeout)
        return 0;
      if (r < 0)
      { r = soap->errnum;
        if (r != SOAP_EINTR && r != SOAP_EAGAIN && r != SOAP_EWOULDBLOCK)
          return 0;
      }
      if (retries-- <= 0)
        return 0;
#ifdef PALM
      r = soap_socket_errno(soap->socket);
      if (r != SOAP_EINTR && retries-- <= 0)
      { soap->errnum = r;
        return 0;
      }
#endif
    }
  }
#ifdef WITH_FASTCGI
  return fread(s, 1, n, stdin);
#else
#ifdef UNDER_CE
  return fread(s, 1, n, soap->recvfd);
#else
#ifdef WMW_RPM_IO
  if (soap->rpmreqid)
    r = httpBlockRead(soap->rpmreqid, s, n);
  else
#endif
#ifdef WIN32
    r = _read(soap->recvfd, s, (unsigned int)n);
#else
    r = read(soap->recvfd, s, (unsigned int)n);
#endif
  if (r >= 0)
    return (size_t)r;
  soap->errnum = soap_errno;
  return 0;
#endif
#endif
}

按照上面的网址链接，解决此问题的办法是：You have to set the recv_timeout and send_timeout values as well. I/O may block otherwise更神奇的是在这个文档中：https://www.genivia.com/tutorials.html 例子里面的soap则添加了超时处理！

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int main()
{
  struct soap *soap = soap_new1(SOAP_IO_KEEPALIVE); /* new context with HTTP keep-alive enabled */
  SOAP_SOCKET m;                                    /* master socket */
  THREAD_TYPE tids[POOLSIZE];                       /* thread pool */
  int i;
  soap->accept_timeout = 24*60*60;             /* quit after 24h of inactivity (optional) */
  soap->send_timeout = soap->recv_timeout = 5; /* 5 sec socket idle timeout */
  soap->transfer_timeout = 10;                 /* 10 sec message transfer timeout */

我就想问官方，你的例子为啥不能一起更新呢？