From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 9966 invoked by alias); 27 Jun 2012 09:51:41 -0000 Received: (qmail 9954 invoked by uid 22791); 27 Jun 2012 09:51:40 -0000 X-SWARE-Spam-Status: No, hits=-3.2 required=5.0 tests=AWL,BAYES_00,KHOP_THREADED,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mail.mvtec.com (HELO mail.mvtec.com) (62.245.183.138) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 27 Jun 2012 09:51:27 +0000 Received: from localhost (localhost [127.0.0.1]) by mail.mvtec.com (8.14.4/8.14.4) with ESMTP id q5R9pPDP008343 for ; Wed, 27 Jun 2012 11:51:25 +0200 X-Spam-Score: -4.306 Received: from mail.mvtec.com ([127.0.0.1]) by localhost (mail.mvtec.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id Hzj-oBan5Haq for ; Wed, 27 Jun 2012 11:51:18 +0200 (CEST) Received: from [192.168.32.114] (mercury.mvtec [192.168.32.114]) by mail.mvtec.com (8.14.4/8.14.4) with ESMTP id q5R9pHdG008336 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO) for ; Wed, 27 Jun 2012 11:51:17 +0200 Message-ID: <4FEAD792.8040200@mvtec.com> Date: Wed, 27 Jun 2012 09:51:00 -0000 From: Eric Doenges User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: crossgcc@sourceware.org Subject: Re: How can I modify the source of new,malloc References: <8347C635-3CB0-4967-8BCB-5AA28FC204B1@gmail.com> <201206262214.37680.yann.morin.1998@free.fr> <4FEACF83.7010904@mvtec.com> In-Reply-To: <4FEACF83.7010904@mvtec.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-IsSubscribed: yes Mailing-List: contact crossgcc-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: crossgcc-owner@sourceware.org X-SW-Source: 2012-06/txt/msg00053.txt.bz2 On 27.06.2012 11:16, Eric Doenges wrote: > On 26.06.2012 22:14, Yann E. MORIN wrote: > >> As Mirko suggested, I'd use a loader trick to pre-load a shared lib that >> overrides the malloc() and free() functions. Something like (untested!): >> >> void* malloc( size_t size ) >> { >> static void* real_malloc; >> >> if( ! real_malloc ) { >> real_malloc = dlsym( RTLD_NEXT, "malloc" ); >> if( ! real_malloc ) { >> panic_and_exit(); >> } >> } >> fprintf( stderr, "Allocating %d bytes\n", size ); >> return real_malloc( size ); >> } >> >> Then, replacing printf with calls to backtrace(3) and backtrace_symbols_fd(3), >> you can know the caller (function, offset), if you have the debug symbols in >> the binaries (libs and executable), in which case you can post-process that >> to find the actual file, function and line at which the call to malloc is >> made. >> >> (Note: do not use backtrace_symbols(3), as it calls malloc! So you have >> to use backtrace_symbols_fd(3)). Just a short addendum: backtrace() calls malloc() internally (see bug report from 2005 http://sourceware.org/bugzilla/show_bug.cgi?id=956), so unfortunately you can't use it in your malloc/free wrapper. -- Dr. Eric Dönges doenges@mvtec.com MVTec Software GmbH | Neherstr. 1 | 81675 München | Germany www.mvtec.com | Tel: +49 89 457695-0 | Fax: +49 89 457695-55 Geschäftsführer: Dr. Wolfgang Eckstein, Dr. Olaf Munkelt Amtsgericht München HRB 114695 -- For unsubscribe information see http://sourceware.org/lists.html#faq