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Date: Thu, 24 Mar 2005 15:11:37 +0100
From: Corinna Vinschen <corinna AT vinschen DOT de>
To: cygwin AT cygwin DOT com
Subject: Re: ssh-agent people (and others) please try latest snapshot
Message-ID: <20050324141137.GB2820@cygbert.vinschen.de>
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References: <20050323181923 DOT GA9283 AT trixie DOT casa DOT cgf DOT cx> <200503232358 DOT j2NNwuMP021542 AT mx1 DOT redhat DOT com>
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On Mar 23 15:55, David Rothenberger wrote:
> On 3/23/2005 10:19 AM, Christopher Faylor wrote:
> >The latest (2005-03-23 as of this writing) snapshot has some more
> >improvements from Corinna wrt unix domain sockets.
> >
> >We're coming close to a 1.5.14 release so I would appreciate it if
> >people would try the latest snapshot and report their successes or
> >failures here.
> 
> This snapshot is not working as well as the 20050322 snapshot for me. I 
> start ssh-agent, add a key to it, and then run
> 
>   while true; do date; ssh-add -l; done
> 
> in four rxvt windows simultaneously. With the previous snapshot this 
> worked fine. With this snapshot, the loops occasionally all hang up for 
> a while and then several windows print
> 
>   Error writing to authentication socket.
>   Error writing to authentication socket.
>   The agent has no identities.

I could reproduce it and apparently the secret event handling isn't quite
as safe under load as expected.  I reworked the whole secret handhake so
that a AF_LOCAL/SOCK_STREAM session now always starts with a handshake on
the socket itself, which exchanges the connect secret and the credentials
and closes the connection if anything happens.  I've tested this solution
under heavy load and it only breaks for me now, if the number of sockets
in the TIME_WAIT state disallows any further connection to the running
ssh-agent.  In this case you'll get a message:

  Could not open a connection to your authentication agent.

This is not a Cygwin problem or only in so far as Cygwin uses AF_INET
sockets to implement AF_LOCAL sockets.  On my XP Pro system there's an
upper bound of about 2000 connections in TIME_WAIT, when the above
message shows up for the first time.

Please test the next Cygwin snapshot again.


Thanks,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          mailto:cygwin AT cygwin DOT com
Red Hat, Inc.

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