From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:51773) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TDyUD-0002Fv-BG for qemu-devel@nongnu.org; Tue, 18 Sep 2012 10:09:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TDyUC-0004No-6u for qemu-devel@nongnu.org; Tue, 18 Sep 2012 10:09:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:65290) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TDyUB-0004Ni-TO for qemu-devel@nongnu.org; Tue, 18 Sep 2012 10:09:12 -0400 Message-ID: <5058806B.1050307@redhat.com> Date: Tue, 18 Sep 2012 16:08:43 +0200 From: Kevin Wolf MIME-Version: 1.0 References: <20120917152149.GB6879@in.ibm.com> <20120917152343.GD6879@in.ibm.com> <5058759C.50207@redhat.com> <505877CC.4040000@redhat.com> In-Reply-To: <505877CC.4040000@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v7 2/5] sockets: Change inet_parse() to accept address specification without port List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Anthony Liguori , Anand Avati , Vijay Bellur , Stefan Hajnoczi , Amar Tumballi , qemu-devel@nongnu.org, Markus Armbruster , Blue Swirl , Avi Kivity , bharata@linux.vnet.ibm.com Am 18.09.2012 15:31, schrieb Paolo Bonzini: > Il 18/09/2012 15:22, Kevin Wolf ha scritto: >> Am 17.09.2012 17:23, schrieb Bharata B Rao: >>> sockets: Change inet_parse() to accept address specification without port >>> >>> From: Bharata B Rao >>> >>> inet_parse() expects address:port. Change it to work without explicit port >>> specification. In addition, don't depend solely on the return value of >> >> Things like "in addition" in a commit message are almost always a sign >> that the patch should be split in two. >> >>> sscanf but also consider the value obtained for %n directive used in sscanf. >>> This ensures that the scanning of malformed inet address isn't flagged as >>> success. >> >> Can you give an example string that would be falsely accepted? To me the >> old checks look fine (even though the new ones are a little bit easier >> to read, so even if they don't fix anything, they might be worth doing). > > "localhost" would fail to be parsed: > > - if (2 != sscanf(str,"%64[^:]:%32[^,]%n",addr,port,&pos)) { > + ret = sscanf(str, "%64[^:]%n:%32[^,]%n", addr, &addr_pos, > + port, &port_pos); > + if (addr_pos == -1 || ret == EOF) { > > because the : in the format string would not match and sscanf would > return 1. Yes, that's the part with making the port optional. Bharata also claims that "scanning of malformed inet address" could falsely succeed before, which I can't see (but which I suspect is what the first two hunks of the patch are meant to address). > However, is it correct to set the port unconditionally to an empty > string? Your usecase makes sense, but perhaps the default port be > passed as an extra parameter to inet_parse instead. I thought about this, too, but didn't care enough to mention it. Now that we're two, yes, I'd like adding a default port parameter. Kevin