From owner-freebsd-hackers@FreeBSD.ORG Wed Apr 23 11:28:32 2008 Return-Path: Delivered-To: hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CF8311065674 for ; Wed, 23 Apr 2008 11:28:32 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from relay02.kiev.sovam.com (relay02.kiev.sovam.com [62.64.120.197]) by mx1.freebsd.org (Postfix) with ESMTP id 63DB08FC25 for ; Wed, 23 Apr 2008 11:28:32 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from [212.82.216.226] (helo=skuns.kiev.zoral.com.ua) by relay02.kiev.sovam.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.67) (envelope-from ) id 1Jod9L-000MOb-3X for hackers@freebsd.org; Wed, 23 Apr 2008 14:28:31 +0300 Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by skuns.kiev.zoral.com.ua (8.14.2/8.14.2) with ESMTP id m3NBSWGc023221 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 23 Apr 2008 14:28:32 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.2/8.14.2) with ESMTP id m3NBSPTJ082863; Wed, 23 Apr 2008 14:28:25 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.2/8.14.2/Submit) id m3NBSPVJ082862; Wed, 23 Apr 2008 14:28:25 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Wed, 23 Apr 2008 14:28:25 +0300 From: Kostik Belousov To: Simun Mikecin Message-ID: <20080423112825.GX18958@deviant.kiev.zoral.com.ua> References: <251738.1147.qm@web36602.mail.mud.yahoo.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Y+QtaVjtxOtr8cXH" Content-Disposition: inline In-Reply-To: <251738.1147.qm@web36602.mail.mud.yahoo.com> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: ClamAV version 0.91.2, clamav-milter version 0.91.2 on skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-4.4 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.2.4 X-Spam-Checker-Version: SpamAssassin 3.2.4 (2008-01-01) on skuns.kiev.zoral.com.ua X-Scanner-Signature: 7155bbd8d023de41950ebecbe4708355 X-DrWeb-checked: yes X-SpamTest-Envelope-From: kostikbel@gmail.com X-SpamTest-Group-ID: 00000000 X-SpamTest-Header: Not Detected X-SpamTest-Info: Profiles 2695 [Apr 23 2008] X-SpamTest-Info: helo_type=3 X-SpamTest-Method: none X-SpamTest-Rate: 0 X-SpamTest-Status: Not detected X-SpamTest-Status-Extended: not_detected X-SpamTest-Version: SMTP-Filter Version 3.0.0 [0278], KAS30/Release Cc: hackers@freebsd.org, mwm-keyword-freebsdhackers2.e313df@mired.org Subject: Re: strdup(NULL) supposed to create SIGSEGV? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 23 Apr 2008 11:28:32 -0000 --Y+QtaVjtxOtr8cXH Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Apr 23, 2008 at 02:38:54AM -0700, Simun Mikecin wrote: > >Yes, it's supposed to segfault. Check out what, say, strcpy does if > >you ask it to copy a NULL pointer. And this is an improvement from the > >bad old days, when they would happily walk through memory starting at > >0..... > >Besides, errno is used to signal errors from system calls. strdup > >isn't a system call, it's a library function (says so at the top of > >the man page). > >Do you have examples of systems where strdup doesn't behave this way? >=20 > According to Open Group strdup should return NULL and set errno. Look at: > http://www.opengroup.org/onlinepubs/009695399/functions/strdup.html >=20 > There is no valid argument for doing segfault instead of above behavior. No, the Open Group specification says the following in the System Interfaces -> 2.1 Use and Implementation of Functions: ### If an argument to a function has an invalid value (such as a value outside the domain of the function, or a pointer outside the address space of the program, or a null pointer), the behavior is undefined. ### Also, see my another answer with the proper incantation from the ANSI C standard. --Y+QtaVjtxOtr8cXH Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.8 (FreeBSD) iEYEARECAAYFAkgPHVkACgkQC3+MBN1Mb4gIQgCbBk7CjAO1FJ13NEf6tjXjSBQt mzcAoIksACyHmxOG8DRi0GYuzDhVJCFD =mhIg -----END PGP SIGNATURE----- --Y+QtaVjtxOtr8cXH--