X-Recipient:	archive-cygwin AT delorie DOT com
X-Spam-Check-By:	sourceware.org
Date:	Thu, 13 Aug 2009 16:15:20 -0400
From:	Christopher Faylor <cgf-use-the-mailinglist-please AT cygwin DOT com>
To:	cygwin AT cygwin DOT com
Subject:	Re: Cygwin1.dll 1.7.0-5x: RSYNC failures in close() system call on pipe file descriptors
Message-ID:	<20090813201520.GA4365@ednor.casa.cgf.cx>
Reply-To:	cygwin AT cygwin DOT com
Mail-Followup-To:	cygwin AT cygwin DOT com
References:	<4A844A97 DOT 1050809 AT sipxx DOT com> <loom DOT 20090813T193850-591 AT post DOT gmane DOT org>
MIME-Version:	1.0
In-Reply-To:	<loom.20090813T193850-591@post.gmane.org>
User-Agent:	Mutt/1.5.20 (2009-06-14)
Mailing-List:	contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id:	<cygwin.cygwin.com>
List-Unsubscribe:	<mailto:cygwin-unsubscribe-archive-cygwin=delorie DOT com AT cygwin DOT com>
List-Subscribe:	<mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive:	<http://sourceware.org/ml/cygwin/>
List-Post:	<mailto:cygwin AT cygwin DOT com>
List-Help:	<mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender:	cygwin-owner AT cygwin DOT com
Mail-Followup-To:	cygwin AT cygwin DOT com
Delivered-To:	mailing list cygwin AT cygwin DOT com

On Thu, Aug 13, 2009 at 07:52:01PM +0000, Eric Blake wrote:
>cygwin <karl <at> sipxx.com> writes:
>
>> 
>> -               if (dup2(to_child_pipe[0], STDIN_FILENO) < 0 ||
>> -                   close(to_child_pipe[1]) < 0 ||
>> -                   close(from_child_pipe[0]) < 0 ||
>> -                   dup2(from_child_pipe[1], STDOUT_FILENO) < 0) {
>> -                       rsyserr(FERROR, errno, "Failed to dup/close");
>> +               if (dup2(to_child_pipe[0], STDIN_FILENO) < 0) {
>> +                       rsyserr(FERROR, errno, "Failed to dup2(to-0)");
>>                         exit_cleanup(RERR_IPC);
>>                 }
>> -               if (to_child_pipe[0] != STDIN_FILENO)
>> -                       close(to_child_pipe[0]);
>> -               if (from_child_pipe[1] != STDOUT_FILENO)
>> -                       close(from_child_pipe[1]);
>
>Ouch.  rsync has a bug even without your patch: if you run rsync with
>stdout closed (as opposed to redirected), then to_child_pipe[0] can be
>1, and you end up closing the just-duplicated from_child_pipe[1] that
>was copied to the new stdout.  To be correct, rsync must compare
>to_child_pipe[0] against both 0 and 1, not just 0 (likewise for
>from_child_pipe[1] against both 0 and 1, not just 1).  Amazing how
>often this type of bug reappears, too - historical cygwin has had it in
>the past with newlib's popen implementation (I fixed it 2006-08-22), as
>well as m4 1.4.13-1 having it due to code from gnulib (I fixed it
>2009-07- 17).

Just a point of order: Cygwin doesn't use the newlib version of
popen.

cgf

--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple

- Raw text -