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Date: Tue, 13 Apr 2010 21:58:18 +0200
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: configure test for accept4 hangs
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On Apr 13 21:20, Corinna Vinschen wrote:
> On Apr 13 10:43, David Rothenberger wrote:
> > While configuring apr-1.4.2 with Cygwin 1.7.5, the test for accept4
> > hung. I don't know much about this API, so I've just disabled it in
> > libapr1 for now, but I wanted to report the hang in case it was a
> > Cygwin bug.
> 
> Boy, this testcase is really stressing the limits.
> 
> The problem is that connect() is called in that loop so fast, that at
> one point the AF_UNIX socket file already exists, but is not yet filled
> with the information necessary to be recognized as AF_UNIX socket.
> Consequentially, at that point connect() fails with EBADF, since it
> assumes you're trying to connect to a file which is not a socket.
> 
> The hang is just a followup effect due to the parent waiting in accept()
> for a connect() which will never happen, because the child process
> already left the connect() loop.
> 
> I try to come up with a more robust solution which also catches this
> scenario.

In CVS I just changed the way the socket file gets created in bind() and
the way it's tested for being a socket file in connect() so this timing
problem shouldn't occur anymore.  Would you mind to test either CVS or
the next developers snapshot from http://cygwin.com/snapshots/ ?


Thanks,
Corinna

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

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