嵌入式下邮件发送

来源：互联网发布：java 接口初始化编辑：程序博客网时间：2024/05/19 20:49

在采用socket实现嵌入式下邮件发送的功能时，由于网络的原因会出现登录邮件服务器失败的情况，此种情况如果socket采用阻塞模式就会导致程序卡在connect函数中出不来。我采用的解决方法是在connect时将socket设置为非阻塞模式，设置10s的超时，然后再将socket设置为非阻塞模式。

具体的代码片段如下：

//获得域名地址
static char *GetIp(char *dn_or_ip)
{
   struct sockaddr_in addr;
   struct hostent *host;
   struct ifreq req;
   int sock;
   if (dn_or_ip == NULL) return NULL;
   if (strcmp(dn_or_ip, "localhost") == 0)
   {
       sock = socket(AF_INET, SOCK_DGRAM, 0);
       strncpy(req.ifr_name, "eth0", IFNAMSIZ);
       if ( ioctl(sock, SIOCGIFADDR, &req) < 0 )
       {
           DBG_PRINT(("ioctl error: %s\n", strerror (errno)));
           return NULL;
        }
       dn_or_ip = (char *)inet_ntoa(*(struct in_addr *) &((struct sockaddr_in *) &req.ifr_addr)->sin_addr);
       shutdown(sock, 2);
       close(sock);
   }
   else
   {
       host = gethostbyname(dn_or_ip);
       if (host == NULL) return NULL;
       dn_or_ip = (char *)inet_ntoa(*(struct in_addr *)(host->h_addr));
    }
   return dn_or_ip;
}

int opt;
int nSendBuf=500;
m_nfd = socket(AF_INET,SOCK_STREAM,0);
if(m_nfd == SOCKET_ERROR)
{
  printf("socket init error/n");
  shutdown(m_nfd,SD_BOTH);
  close(m_nfd);
  return 0;
}

opt = SO_REUSEADDR;
setsockopt(m_nfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
setsockopt(m_nfd,SOL_SOCKET,SO_SNDBUF,(const char*)&nSendBuf,sizeof(int));

int flags = fcntl(m_nfd,F_GETFL,0);
fcntl(m_nfd,F_SETFL,flags|O_NONBLOCK);

//入参检查
if ((szHost == NULL) || (*szHost == '/0'))
{
  return 0;
}
    hostip = GetIp(const_cast<char*>(szHost));
if(hostip == NULL)
{
  return 0;
}
memset(&m_RemoteSockAddr,0,sizeof(struct sockaddr));
m_RemoteSockAddr.sin_family = AF_INET;
m_RemoteSockAddr.sin_port   = htons(m_nPort);
m_RemoteSockAddr.sin_addr.s_addr = inet_addr(hostip);

m_nResult = connect(m_nfd,(struct sockaddr *)&m_RemoteSockAddr,sizeof(struct sockaddr));
if( m_nResult < 0 && errno != EINPROGRESS)
{
  printf("connect erro:%d/n",errno);
  shutdown(m_nfd,SD_BOTH);
  close(m_nfd);
  return 0;
}

fd_set sendSeT;
FD_ZERO(&sendSeT);
FD_SET(m_nfd,&sendSeT);

timeval timeout;
timeout.tv_sec= 10;
timeout.tv_usec= 0;
m_nResult= select(m_nfd+1,0,&sendSeT,0,&timeout);

if((SOCKET_ERROR==m_nResult)||!m_nResult)
{
  printf("connect erro:%d/n",errno);
  shutdown(m_nfd,SD_BOTH);
  close(m_nfd);
  return 0;

}

printf("connect Mail Host success!!!!/n");

fcntl(m_nfd, F_SETFL, flags);