From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:32885) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QOVMy-0007rR-DT for qemu-devel@nongnu.org; Mon, 23 May 2011 09:40:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QOVMw-0005pE-Q4 for qemu-devel@nongnu.org; Mon, 23 May 2011 09:40:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20595) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QOVMw-0005p4-JG for qemu-devel@nongnu.org; Mon, 23 May 2011 09:40:26 -0400 Date: Mon, 23 May 2011 14:40:21 +0100 From: "Daniel P. Berrange" Message-ID: <20110523134021.GT24143@redhat.com> References: <20110520180331.GA21837@amd.home.annexia.org> <4DD6AEB9.6060506@codemonkey.ws> <20110523130411.GR24143@redhat.com> <4DDA620F.1090308@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <4DDA620F.1090308@codemonkey.ws> Subject: Re: [Qemu-devel] [PATCH] qemu: json: Fix parsing of integers >= 0x8000000000000000 Reply-To: "Daniel P. Berrange" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: qemu-devel@nongnu.org, "Richard W.M. Jones" , Luiz Capitulino On Mon, May 23, 2011 at 08:33:03AM -0500, Anthony Liguori wrote: > On 05/23/2011 08:04 AM, Daniel P. Berrange wrote: > >On Fri, May 20, 2011 at 01:11:05PM -0500, Anthony Liguori wrote: > >>On 05/20/2011 01:03 PM, Richard W.M. Jones wrote: > >>> > >>>There seem to be a few unsafe uses of strto* functions. This patch > >>>just fixes the one that affects me :-) > >> > >>Sending an integer of this size is not valid JSON. > >> > >>Your patch won't accept negative numbers, correct? > >> > >>JSON only supports int64_t. > > > >That's not really true. JSON supports arbitrarily large numbers > >& integers. > > Try the following snippet in your browser: > > > > > > > > The actual value of the alert will surprise you :-) > > Integers in Javascript are actually represented as doubles > internally which means that integer constants are only accurate up > to 52 bits. > > So really, we should cap integers at 32-bit :-/ > > Have I mentioned recently that I really dislike JSON... NB, I am distinguishing between JSON the generic specification and JSON as implemented in web browsers. JSON the specification has *no* limitation on integers. Any limitation, like the one you demonstrate, is inherantly just specific to the implementation. We have no need to limit ourselves to what web browsers currently support for integers in JSON. Indeed, limiting ourselves to what browsers support will make the JSON monitor mode essentially useless, requiring yet another new mode with a format which can actually represent the data we need to use. What I suggested is in compliance with the JSON specification and allows us to support uint64 which we need for commands which take disk or memory offsets. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|