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Date: Tue, 13 Apr 2010 21:20:10 +0200
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
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Subject: Re: configure test for accept4 hangs
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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.


Thanks for the testcase,
Corinna

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

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