[apue] syslog 导致 accept 出错?

 1 void serve (int sockfd)
 2 {
 3     int ret; 
 4     int clfd; 
 5     int status; 
 6 
 7     FILE *fp; 
 8     pid_t pid; 
 9     char buf[BUFLEN]; 
10 
11     for (;;) { 
12         clfd = accept (sockfd, NULL, NULL); 
13         if (clfd < 0) { 
14             syslog (LOG_ERR, "accept error: %d, %s", errno, strerror (errno)); 
15             //if (errno == EOPNOTSUPP)
16             //{
17             //    syslog (LOG_INFO, "retry.."); 
18             //    continue; 
19             //}
20 
21             exit (1); 
22         }
23 
24         fp = popen ("/usr/bin/uptime", "r"); 
25         if (fp == NULL) { 
26             sprintf (buf, "error: %s\n", strerror (errno)); 
27             ret = send (clfd, buf, strlen (buf), 0); 
28             syslog (LOG_ERR, "write back %d for error", ret); 
29         } else { 
30             while (fgets (buf, BUFLEN, fp) != NULL) 
31             {
32                 ret = send (clfd, buf, strlen (buf), 0); 
33                 // very amazing, add these log will lead to accept failed with EOPNOTSUPP (95)
34                 // maybe syslog used dgram socket confuse us..
35                 syslog (LOG_ERR, "write back %d", ret); 
36             }
37 
38             pclose (fp); 
39         }
40 
41         close (clfd); 
42     }
43 }

[yunhai@localhost 16.chapter]$ ./uptime_tcp_clt
connect ok
 02:02:26 up 6 days,  4:40,  5 users,  load average: 0.00, 0.00, 0.00

ruptimed: write back 70

[yunhai@localhost 16.chapter]$ ./uptime_tcp_clt
connect failed, retry...
connect failed, retry...
connect failed, retry...

ruptimed: accept error: 95, Operation not supported