X-Recipient: archive-cygwin AT delorie DOT com
X-Spam-Check-By: sourceware.org
Date: Sat, 5 Dec 2009 10:48:55 +0100
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: [1.7] getgroups regression?
Message-ID: <20091205094855.GQ8059@calimero.vinschen.de>
Reply-To: cygwin AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
References: <loom DOT 20091204T232305-913 AT post DOT gmane DOT org>  <loom DOT 20091204T233949-57 AT post DOT gmane DOT org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <loom.20091204T233949-57@post.gmane.org>
User-Agent: Mutt/1.5.20 (2009-06-14)
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
Precedence: bulk
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 Dec  4 22:48, Eric Blake wrote:
> Meanwhile, is sorting and/or pruning duplicate getgroups results something that 
> cygwin should consider doing?  POSIX is explicit that the result is a 
> mathematical set, and that two processes can have the same set membership but 
> different orders based on the sequence of events that created those two 
> processes.  But will Linux ever list a duplicate, even if duplicates appear 
> in /etc/group?

Probably not.  I assume the job of getgroups() is much easier on Linux.
It just has to list the gids in the group list.  Cygwin fetches the
/etc/group file and verifies for each entry if its SID is in the process
token.  Avoiding dups requires YA loop in the loop, I don't think it's
actually worth the effort.


Corinna

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

--
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