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<== Date ==> | <== Thread ==> |
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Subject: | RE: iocLogServer connection problem on win32-x86 platform |
From: | "Hill, Jeff" <[email protected]> |
To: | Janez Golob <[email protected]>, "[email protected]" <[email protected]> |
Date: | Tue, 4 Jun 2013 14:10:17 +0000 |
Ø
What is the reason for using half-duplex connection only? The purpose was to release resources that were not being used. I have not observed any issues resulting from
this choice in the past, but the log server maybe isn’t run on windows all that often. I suspect that it won’t cause any issues to remove that shutdown call, other than additional resource consumption, although I haven’t touched this code in some time. Could you file a bug report on this issue? Thanks, Jeff From: [email protected]
[mailto:[email protected]] On Behalf Of Janez Golob Hi All, I am running iocLogServer on the win32-x86 platform (base 3.14.12, VS 2010 Express).
If the connection to the log server is inactive for more than 90 second (more precisely, if there are no messages logged) the following error is reported by the IOC (IOC log client): epics> log client: lost contact with log server at "127.0.0.1:7111" because "An existing connection was forcibly closed by the remote host. " I was digging a bit in to the iocLogServer.c source code and it seems to me the following statement causes the problem: 494 status =
shutdown(pclient->insock,
SHUT_WR); It seems to me that
shutting down one half of the connection can also close the opposite half. On the socket level the below two short python programs can be used to reproduce the behavior. What is the reason for using half-duplex connection only? To my experience the shutdown function is used to close the connection gracefully. Regards, Janez Server side: import
socket HOST =
'' PORT = 50007 s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.bind((HOST, PORT)) s.listen(1) conn, addr = s.accept() print
'Connected by', addr conn.shutdown(socket.SHUT_WR) while
1: data = "">
if
not data:
break
print
'"{}"'.format(data) conn.close() Client side: import
socket import
time HOST =
'localhost' PORT = 50007 s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((HOST, PORT)) s.send('This
should succeed') time.sleep(100) s.send('This
shuld fail') |