From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24447 invoked by alias); 3 Jul 2007 01:13:30 -0000 Received: (qmail 24438 invoked by uid 22791); 3 Jul 2007 01:13:30 -0000 X-Spam-Check-By: sourceware.org Received: from b.mail.sonic.net (HELO b.mail.sonic.net) (64.142.19.5) by sourceware.org (qpsmtpd/0.31) with ESMTP; Tue, 03 Jul 2007 01:13:28 +0000 Received: from webmail.sonic.net (b.webmail.sonic.net [64.142.100.148]) by b.mail.sonic.net (8.13.8.Beta0-Sonic/8.13.7) with ESMTP id l631DQmq007050; Mon, 2 Jul 2007 18:13:26 -0700 Received: from 12.7.175.2 (SquirrelMail authenticated user msnyder) by webmail.sonic.net with HTTP; Mon, 2 Jul 2007 18:13:26 -0700 (PDT) Message-ID: <7995.12.7.175.2.1183425206.squirrel@webmail.sonic.net> In-Reply-To: <20070701155543.GF10872@caradoc.them.org> References: <13902.12.7.175.2.1183067383.squirrel@webmail.sonic.net> <20070628215829.GA10350@caradoc.them.org> <6989.12.7.175.2.1183069038.squirrel@webmail.sonic.net> <20070628224250.GB12578@caradoc.them.org> <10837.12.7.175.2.1183071869.squirrel@webmail.sonic.net> <20070701155543.GF10872@caradoc.them.org> Date: Tue, 03 Jul 2007 01:13:00 -0000 Subject: Re: [OB] cli/cli-script.c, null ptr guard From: msnyder@sonic.net To: msnyder@sonic.net, gdb-patches@sourceware.org User-Agent: SquirrelMail/1.4.9a MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2007-07/txt/msg00046.txt.bz2 > On Thu, Jun 28, 2007 at 04:04:29PM -0700, Michael Snyder wrote: >> > On Thu, Jun 28, 2007 at 03:17:18PM -0700, msnyder@sonic.net wrote: >> >> > No, I don't think this is obvious. What does it mean to have a >> null >> >> > string here and how can it happen? I'm pretty sure it can't, and >> the >> >> > if check is just clutter. >> >> >> >> The reasoning is that, since we checked it for NULL in the >> >> first statement of the function, we must believe that the >> >> possibility exists for it to be NULL. >> > >> > Right. So, is it a sensible check? Or should it be removed, or >> > should the condition for the error be simplified? >> >> Well, it either makes sense to check it for null, or it doesn't. >> If the new test is redundant, so is the old one. Whoever wrote >> it in the first place seemed to think it was worth checking. >> >> This is called from a number of places, but they are all local to the >> module. >> >> Ultimately the argument comes from the command parser. >> It's one of those typical (char *args, int from_tty) things. > > There's four calls to build_command_line. Three are passed a freshly > incremented pointer, so it can never be NULL. That's > if/while/commands. The other one came from get_command_line. Those > can be NULL - well, I'm not sure, but I think they can. They're > always if/while. > > So how about adding gdb_assert (args != NULL) after the error call, > like below? If you follow where the result of this function goes, > if we actually set cmd->line = NULL we will crash. Yes, OK, will commit as shown.