From owner-freebsd-current@FreeBSD.ORG Mon Feb 9 06:33:00 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 380EC16A4CE for ; Mon, 9 Feb 2004 06:33:00 -0800 (PST) Received: from smtp.des.no (flood.des.no [217.116.83.31]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0C6CD43D1D for ; Mon, 9 Feb 2004 06:33:00 -0800 (PST) (envelope-from des@des.no) Received: by smtp.des.no (Pony Express, from userid 666) id C4C53530D; Mon, 9 Feb 2004 15:32:58 +0100 (CET) Received: from dwp.des.no (des.no [80.203.228.37]) by smtp.des.no (Pony Express) with ESMTP id 191495309; Mon, 9 Feb 2004 15:32:48 +0100 (CET) Received: by dwp.des.no (Postfix, from userid 2602) id 883A233C6F; Mon, 9 Feb 2004 15:32:48 +0100 (CET) To: Barney Wolff References: <20040209023623.GA30071@xor.obsecurity.org> <20040209051116.GA42857@pit.databus.com> From: des@des.no (Dag-Erling =?iso-8859-1?q?Sm=F8rgrav?=) Date: Mon, 09 Feb 2004 15:32:48 +0100 In-Reply-To: <20040209051116.GA42857@pit.databus.com> (Barney Wolff's message of "Mon, 9 Feb 2004 00:11:16 -0500") Message-ID: User-Agent: Gnus/5.090024 (Oort Gnus v0.24) Emacs/21.3 (berkeley-unix) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on flood.des.no X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=AWL autolearn=no version=2.63 cc: current@freebsd.org cc: Kris Kennaway Subject: Re: grep bug X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 09 Feb 2004 14:33:00 -0000 Barney Wolff writes: > On Sun, Feb 08, 2004 at 06:36:23PM -0800, Kris Kennaway wrote: >> kkenn@rot13:~ grep -r foo / > /dev/null >> grep: /dev/network: Permission denied >> grep: /dev/geom.ctl: Permission denied >> grep: /dev/devctl: Permission denied >> grep: /dev/ata: Permission denied >> grep: /dev/console: Permission denied >> grep in realloc(): error: allocation failed >> ^C^C^CAbort (core dumped) > > grepping /dev/zero seems to fail. /dev/zero will provide grep with infinite amounts of data. So will /dev/random. Yet other device nodes (serial ports for instance) will cause grep to block because they provide neither data nor EOF. The /dev/zero case is a little special because grep tries to read in an entire line, but /dev/zero provides an endless string of zeroes with no EOL in sight. /dev/random, on the other hand, is pretty much guaranteed to provide EOL every 256 bytes on average. DES --=20 Dag-Erling Sm=F8rgrav - des@des.no