From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1KXCPc-0005mG-R7
	for qemu-devel@nongnu.org; Sun, 24 Aug 2008 06:01:33 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1KXCPb-0005lP-6n
	for qemu-devel@nongnu.org; Sun, 24 Aug 2008 06:01:32 -0400
Received: from [199.232.76.173] (port=60617 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1KXCPa-0005lG-Vp
	for qemu-devel@nongnu.org; Sun, 24 Aug 2008 06:01:31 -0400
Received: from mail2.shareable.org ([80.68.89.115]:36525)
	by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32)
	(Exim 4.60) (envelope-from <jamie@shareable.org>) id 1KXCPa-0000G2-LI
	for qemu-devel@nongnu.org; Sun, 24 Aug 2008 06:01:30 -0400
Date: Sun, 24 Aug 2008 11:01:29 +0100
From: Jamie Lokier <jamie@shareable.org>
Subject: Re: [Qemu-devel] vnc port selection
Message-ID: <20080824100128.GB24946@shareable.org>
References: <48AD99CF.6070004@redhat.com> <48ADB43D.9050401@qumranet.com>
	<48ADB58D.9070409@codemonkey.ws> <48B121D6.6060008@qumranet.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <48B121D6.6060008@qumranet.com>
Reply-To: qemu-devel@nongnu.org
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: qemu-devel@nongnu.org
Cc: Xen Development Mailing List <xen-devel@lists.xensource.com>

Avi Kivity wrote:
> Anthony Liguori wrote:
> >
> >>Alternatively, have the management application pass an fd denoting 
> >>the socket.
> >
> >If you are allocating the ports in the management tool, then just tell 
> >QEMU what port to open up.  I don't think you gain anything passing an 
> >fd.
> >
> 
> It prevents races, allows listening on non-traditional sockets (vnc over 
> unix-domain), and allows privilege separation.

Agreed: races are particularly irksome.

I have the same problem in another application, where one program
allocates a fee port, but another (SSH tunnel) opens it.  It's very
annoying that the second program fails from time to time, due to the
race.

-- Jamie