From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S271183AbTHLVyR (ORCPT ); Tue, 12 Aug 2003 17:54:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S271185AbTHLVyR (ORCPT ); Tue, 12 Aug 2003 17:54:17 -0400 Received: from gate.firmix.at ([80.109.18.208]:19921 "EHLO buffy.firmix.at") by vger.kernel.org with ESMTP id S271183AbTHLVyQ (ORCPT ); Tue, 12 Aug 2003 17:54:16 -0400 Subject: Re: generic strncpy - off-by-one error From: Bernd Petrovitsch To: Anthony Truong Cc: Alan Cox , Linux Kernel Mailing List In-Reply-To: <1060708460.12532.59.camel@dhcp22.swansea.linux.org.uk> References: <1060653362.5294.58.camel@huykhoi> <1060708460.12532.59.camel@dhcp22.swansea.linux.org.uk> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.8.99 Date: 12 Aug 2003 23:53:58 +0200 Message-Id: <1060725239.1500.22.camel@gimli.at.home> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2003-08-12 at 19:14, Alan Cox wrote: > On Maw, 2003-08-12 at 02:56, Anthony Truong wrote: > > Thanks for pointing that out to me. However, I don't think the kernel > > strncpy implementation is exactly the same as that of Standard C lib > > It is true it doesnt need to be Nevertheless it is defined the inefficient way by the C-Standard and lots of people actually really know this. So IMHO (re)implementing a function called "strncpy" differently doesn't make much sense. > > implementation. Iwas just looking at it from the kernel code context. The kernel is implemented in C. And the function strncpy() _is_ already defined by C. So please use at least another name. Given the existence of strlcpy() - http://www.courtesan.com/todd/papers/strlcpy.html- this problem already has been solved. > > There's a point in doing it the "kernel" way, to save precious CPU > > cycles from being wasted otherwise. > > CPU cycles, got lots of those 8). If its going to do anything it might > be to reference an extra cache line. For people who dont need padding > 2.6 has strlcpy. Lots of drivers assume strncpy fills the entire block ACK. To use strlcpy() is correct solution (if padding is not required). Bernd