I use socat 1.7.3.1-r0并在alpine 3.3linux服务器：
socat -d -d -d PTY,link=/dev/ttyFOOBAR,echo=0,raw,unlink-close=0 TCP-LISTEN:7000,forever,reuseaddr
Socat将侦听客户端并通过从虚拟串行端口传递数据来创建双向通信/dev/ttyFOOBAR到客户端并通过 TCP 再次返回。一旦客户端断开连接socat应该退出。
建立此类连接后，socat 会记录以下内容：
I socat by Gerhard Rieger - see www.dest-unreach.org
I This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit. (http://www.openssl.org/)
I This product includes software written by Tim Hudson ([email protected] /cdn-cgi/l/email-protection)
I setting option "symbolic-link" to "/dev/ttyFOOBAR"
I setting option "echo" to 0
I setting option "raw"
I setting option "unlink-close" to 0
I openpty({5}, {6}, {"/dev/pts/3"},,) -> 0
N PTY is /dev/pts/3
I setting option "forever" to 1
I setting option "so-reuseaddr" to 1
I socket(2, 1, 6) -> 7
I starting accept loop
N listening on AF=2 0.0.0.0:7000
I accept(7, {2, AF=2 CLIENT_IP:PORT}, 16) -> 8
N accepting connection from AF=2 CLIENT_IP:PORT on AF=2 172.20.0.2:7000
I permitting connection from AF=2 CLIENT_IP:PORT
I close(7)
I resolved and opened all sock addresses
N starting data transfer loop with FDs [5,5] and [8,8]
ss服务器上的命令打印：
Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port
tcp ESTAB 0 0 172.20.0.2:7000 CLIENT_IP:PORT
问题是，当我断开客户端连接（通过将其关闭）时，tcp 连接仍然建立，并且 socat 没有添加任何日志记录。ss仍将连接显示为 ESTAB。有什么想法吗？当我再次连接客户端时，日志中会显示以下内容：
W read(8, 0x7fa8f48c4020, 8192): Connection reset by peer
N socket 2 to socket 1 is in error
N socket 2 (fd 8) is at EOF
I poll timed out (no data within 0.500000 seconds)
I close(5)
I shutdown(8, 2)
I shutdown(8, 2): Socket not connected
N exiting with status 0
但为什么会在连接而不是断开连接时发生这种情况呢？
