通过无连接数据报 Unix 套接字发送时出现 ECONNREFUSED 的可能原因是什么?
也欢迎任何有关如何调试此问题的建议,因为此问题是可重现的。
无论是否使用 sendto()
或 sendmsg()
我都会收到错误消息。
if ((sock = socket(PF_UNIX, SOCK_DGRAM, 0)) < 0)
{
return 0;
}
unlink("/tmp/serv");
addr.sun_family = AF_UNIX;
strncpy(&addr.sun_path[0], "/tmp/serv", sizeof(addr.sun_path));
if (bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0)
{
return 0;
}
sockaddr_un from;
int fromlen = sizeof(from);
if (recvfrom(sock, &i, sizeof(i),0,(sockaddr*)&from,(socklen_t*)&fromlen) < 0 )
{
//some error handling code
}
printf("from.sun_family=%d, from.sun_path=%s",from.sun_family,from.sun_path); // this prints, as expected "from.sun_family=1, from.sun_path=/tmp/client"
strncpy(&addr.sun_path[0], "/tmp/client", sizeof(addr.sun_path));
sendto(sock,"abc",3,0,(sockaddr*)&addr, sizeof(addr)); //this fails with ECONNREFUSED
最佳答案
来自 man 7 unix
:
ECONNREFUSED The remote address specified by connect(2) was not a listening socket. This error can also occur if the target filename is not a socket.
在 Linux 中,sendto
在 Unix 套接字上 does the following :
1548 if (sock_flag(other, SOCK_DEAD)) {
1549 /*
1550 * Check with 1003.1g - what should
1551 * datagram error
1552 */
1553 unix_state_unlock(other);
1554 sock_put(other);
1555
1556 err = 0;
1557 unix_state_lock(sk);
1558 if (unix_peer(sk) == other) {
1559 unix_peer(sk) = NULL;
1560 unix_state_unlock(sk);
1561
1562 unix_dgram_disconnected(sk, other);
1563 sock_put(other);
1564 err = -ECONNREFUSED;
1565 } else {
1566 unix_state_unlock(sk);
1567 }
1568
1569 other = NULL;
1570 if (err)
1571 goto out_free;
1572 goto restart;
1573 }
换句话说,您发送到的套接字的另一端没有读取器,或者套接字不再存在于文件系统中。
关于c++ - 数据报 Unix 套接字上的 ECONNREFUSED,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26016189/