From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262994AbVALBpm (ORCPT ); Tue, 11 Jan 2005 20:45:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262995AbVALBpm (ORCPT ); Tue, 11 Jan 2005 20:45:42 -0500 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:44259 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S262994AbVALBp3 (ORCPT ); Tue, 11 Jan 2005 20:45:29 -0500 Date: Tue, 11 Jan 2005 20:36:41 -0200 From: Marcelo Tosatti To: David Lang Cc: Jesper Juhl , Andries Brouwer , "Barry K. Nathan" , Linus Torvalds , Alan Cox , Lukasz Trabinski , Linux Kernel Mailing List Subject: Re: [PATCH] make uselib configurable (was Re: uselib() & 2.6.X?) Message-ID: <20050111223641.GA27100@logos.cnet> References: <20050111235907.GG2760@pclin040.win.tue.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.5.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 11, 2005 at 05:18:16PM -0800, David Lang wrote: > On Wed, 12 Jan 2005, Jesper Juhl wrote: > > >On Wed, 12 Jan 2005, Andries Brouwer wrote: > > > >>On Tue, Jan 11, 2005 at 02:51:27PM -0800, Barry K. Nathan wrote: > >>>On Sat, Jan 08, 2005 at 10:46:19AM -0800, Linus Torvalds wrote: > >>>>Another issue is likely that we should make the whole "uselib()" > >>>>interfaces configurable. I don't think modern binaries use it (where > >>>>"modern" probably means "compiled within the last 8 years" ;). > >> > >>libc 5.4.46 is from 1998-06-21 or so, glibc 2.0.5 from 1997-08-25 or so. > >> > >>>+config SYS_USELIB > >>>+ bool "sys_uselib syscall support (needed for old binaries)" > >>>+ ---help--- > >>>+ Many old binaries (e.g. dynamically linked a.out binaries, and > >>>+ ELF binaries that are dynamically linked against libc5), require > >>>+ the sys_uselib syscall. However, on the typical Linux system, this > >>>+ code is just old cruft that no longer serves a purpose. > >>>+ > >>>+ If you are unsure, say "N" if you care more about security and > >>>+ trimming bloat, or say "Y" if you care more about compatibility > >>>+ with old software. (If you will answer "Y" or "M" to BINFMT_AOUT, > >>>+ below, you probably should answer "Y" here.) > >> > >>s/sys_uselib/uselib/ > >>The system call is uselib(). > >> > >>Hmm - old cruft.. Why insult your users? > >>I do not have source for Maple. And my xmaple binary works just fine. > >>But it is a libc4 binary. > >> > >>You mean "on the typical recently installed Linux system, with nothing > >>but the usual Linux utilities". > >> > >>People always claim that Linux is good in preserving binary compatibility. > >>Don't know how true that was, but introducing such config options doesnt > >>help. > >> > >>Let me also mutter about something else. > >>In principle configuration options are evil. Nobody wants fifty thousand > >>configuration options. But I see them multiply like ioctls. > >>There should be a significant gain in having a config option. > >> > >I don't have much to say exceppt express my agreement. That is so very > >true. > >The less config options the user is presented with the better, and for > >each config option there should be a very good reason. Very much agreed. > > > > > >>Maybe some argue that there is a gain in security here. Perhaps. > >>Or a gain in memory. It is negligible. > >>I see mostly a loss. > >> > >>There are more ancient system calls, like old_stat and oldolduname. > >>Do we want separate options for each system call that is obsoleted? > >> > >IMO, no, we do not. > > how about something like the embedded, experimental, and broken options. > that way normal users can disable all of them at a stroke, people who need > them can add them in. Thats just not an option - you would have zillions of config options. Moreover this is a system call, and the system call interface is one of the few supposed to be stable. You shouldnt simply assume that "no one will ever use sys_uselib()" - there might be programs out there who use it. I agree with Andries.