recvfrom问题记录

<span style="font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">    偶然情况下recvfrom函数出现了不正常的情况，目前还没有复现。</span>

贴出部分的代码和日志问价里面的信息。

struct timeval tv_out;

tv_out.tv_sec = 120;
tv_out.tv_usec = 0;

setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, &tv_out, sizeof(tv_out));

 udp_media_cond = 1;

    while(udp_media_cond)
    {
        memset(buf, 0, sizeof(buf));
        memset(temp, 0, sizeof(temp));
        len = recvfrom(sockfd, buf, sizeof(buf), 0, (struct sockaddr *)&client_addr_from, &fromlen);

        if (0 >= len)
        {
            syslog(LOG_DEBUG, "DEBUG:recv data error!");
            syslog(LOG_DEBUG, "DEBUG:uid is '%s', port is '%d'.", uid, port);
            if (EAGAIN == errno)
            {
                syslog(LOG_DEBUG, "DEBUG: EAGAIN!");
                //return 0;
            }
        }

        buf[len] = '\0';
}

日志里面的打印：

Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:recv data error!
Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:uid is '00060110', port is '5500'.
Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG: EAGAIN!
Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:recv data error!
Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:uid is '00060110', port is '5500'.
Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:recv data error!
Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:uid is '00060110', port is '5500'.
Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:recv data error!
Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:uid is '00060110', port is '5500'.
Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:recv data error!
Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:uid is '00060110', port is '5500'.

后面那个打印了十几W条

Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf rsyslogd-2177: imuxsock begins to drop messages from pid 2218 due to rate-limiting
Oct 27 12:26:22 32f32c8c-8c75-4249-bbf2-afa068de9aaf rsyslogd-2177: imuxsock lost 176521 messages from pid 2218 due to rate-limiting

正常的情况是不会有这些的打印，打印

Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG: EAGAIN!

是因为过了2分钟，没有收到任何数据。

狂打印

Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:recv data error!
Oct 27 12:26:16 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:uid is '00060110', port is '5500'.

就是不正常的，除非开始接受数据，每次接受的数据为为空。

这个线程最后是死掉了，过了一段时候后

Oct 27 12:26:22 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:recv data error!
Oct 27 12:26:22 32f32c8c-8c75-4249-bbf2-afa068de9aaf rsyslogd-2177: imuxsock begins to drop messages from pid 2218 due to rate-limiting
Oct 27 12:26:29 32f32c8c-8c75-4249-bbf2-afa068de9aaf rsyslogd-2177: imuxsock lost 3408 messages from pid 2218 due to rate-limiting
Oct 27 12:26:29 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:recv data error!
Oct 27 12:26:29 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG:uid is '00060001', port is '5501'.
Oct 27 12:26:29 32f32c8c-8c75-4249-bbf2-afa068de9aaf server_debug:[2218]: DEBUG: EAGAIN!

主线程收不到任何的数据，也有可能是客户端没有发送（可能性极小），该线程再也没有任何打印。