Thanks, Paul.

Your report is useful for me.
I realize this problem can happen not only my source.

I hope this is a buf in JSch library and fix it.
But I can prepare for the problem, because I know it happens.

Regards,

(2010/01/01 15:01), Paul Michael Reilly さんは書きました:
> On 12/29/2009 03:55 AM, Paul Michael Reilly wrote:
>> On 12/28/2009 12:12 AM, matsuda wrote:
>>> Hi,
>>>
>>> I have a trouble using (SSH)Exec problem.
>>> It is that "channel object" sometimes fails to detect the close signal.
>>> Can anyone help me?
>>>
>>> While program does polling a remote SSH server by "ls" command,
>>> "if(channel.isClosed())" sometimes doesn't change true forever!
>>>
>>> According to my experience, it occurs after running some nights or
>>> more than 1000 times loop.
>>>
>>> For debug, I add below test message, then it appears.
>>> It shows exit status code changed( from -1 to 0 ),
>>> but channel hasn't closed.
>>>     if( !channel.isClosed()&&   channel.getExitStatus() == 0 ){
>>>       System.out.println("before close exit-status changed!" );
>>>     }
>>>
>>>
>>> Q1. Is is a known problem?
>>>
>>> Q2. How should I write program to recover this problem?
>> These are very good questions.  I have encountered both recently myself.
>>    I also can attest that disconnects I know to exist were not reported
>> by my running application, so either I misunderstand the semantics of
>> Channel.isClosed() and/or Channel.isConnected() or in fact there is a
>> bug in this part of the JSch library.
> 
> I still do not have a good feel whether there is a bug in the 
> Channel/Session classes wrt disconnect and closing not being detected 
> and reported properly.  I think there is but would be hard pressed to 
> clearly state what it is.
> 
> The new application code I have written to work around this very real 
> problem tries to force the issue by opening a short lived ChannelExec 
> connection and executing a simple (date) command.  The theory being that 
> if the Session has died (been closed or disconnected but still reports a 
> connected status) then the death will be revealed for sure in the 
> attempt to transfer bytes.  Once the workaround can be shown to be 
> working I will attempt to find the real problem with the library while 
> still having a useful application.  I expect it will take much effort 
> and considerable time.
> 
> -pmr

----------------------------------
Yukimasa Matsuda
   Quatre-i Science Co., Ltd.
     e-mail: mats...@i4s.co.jp
     http://www.i4s.co.jp
----------------------------------


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