From owner-freebsd-hackers@FreeBSD.ORG Fri Sep 5 15:53:58 2014 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 86A63F52; Fri, 5 Sep 2014 15:53:58 +0000 (UTC) Received: from bigwig.baldwin.cx (bigwig.baldwin.cx [IPv6:2001:470:1f11:75::1]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 5C8A31918; Fri, 5 Sep 2014 15:53:58 +0000 (UTC) Received: from jhbbsd.localnet (unknown [209.249.190.124]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id 4C90AB9C3; Fri, 5 Sep 2014 11:53:57 -0400 (EDT) From: John Baldwin To: Julian Elischer Subject: Re: Can anyone help clarify details about the FreeBSD system call interface? Date: Fri, 5 Sep 2014 11:43:32 -0400 User-Agent: KMail/1.13.5 (FreeBSD/8.4-CBSD-20140415; KDE/4.5.5; amd64; ; ) References: <2041449.H6lUHcsTDl@ralph.baldwin.cx> <54090FDB.6090801@freebsd.org> In-Reply-To: <54090FDB.6090801@freebsd.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201409051143.33213.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Fri, 05 Sep 2014 11:53:57 -0400 (EDT) Cc: freebsd-hackers@freebsd.org, kib@freebsd.org, Steven Stewart-Gallus , Benjamin Kaduk X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 05 Sep 2014 15:53:58 -0000 On Thursday, September 04, 2014 9:20:27 pm Julian Elischer wrote: > On 9/4/14, 7:06 AM, John Baldwin wrote: > > On Wednesday, September 03, 2014 05:30:01 PM Benjamin Kaduk wrote: > >> On Thu, 28 Aug 2014, Steven Stewart-Gallus wrote: > >>>> svn blame says that the whole implementation dates from r1541. > >>>> Looks like > >>>> it was never implemented. Some googling indicates that it was a > >>>> plannedroutine to set the stack size, which was never implemented, > >>>> anywhere. > >>>> > >>>> The locking comments were added in r79224, but the implementation is > >>>> otherwise from r1541, i.e., it was never implemented. > >>> Alright, so sys/kern/syscalls.master can be patched somewhat like so > >>> and I won't need to document them? > >>> > >>> -72 AUE_O_VADVISE STD { int ovadvise(int anom); } vadvise \ > >>> - ovadvise_args int > >>> +72 AUE_NULL OBSOL ovadvise > >>> > >>> -70 AUE_SSTK STD { int sstk(int incr); } > >>> +70 AUE_SSTK OBSOL sstk > >> I don't think so; I think that would be a regression. > >> > >> We do currently provide implementations for these syscalls, that just > >> happen to always return failure. I think that the OBSOL annotation > >> corresponds to a complete lack of implementation. Perhaps it would be > >> acceptable at a major release boundary, but this is not my area of > >> expertise. > > For these two calls, I doubt anything is actually using them. They've been > > stubs since the Mach VM was imported into BSD in 1990. We don't ship a system > > call for creat() anymore either. In this particular case, I think it would be > > more of a feature if those symbols disappeared from libc and caused link > > errors. > have we ever shipped code for creat? > > if we lose teh ability to run FreeBSD 1.1 chroots I'll be most upset.. > it's a great > selling point when pointing out our commitment to ABI stability and > backwards > portability. These system calls were NOPs in 4.4 BSD. vadvise was marked as obsolete ('ovadvise') in syscalls.master when it was first imported in 1989: http://svnweb.freebsd.org/csrg/sys/kern/syscalls.master?view=markup&pathrev=37325 I can't actually find the implementations of vadvise() and sstk() prior to the Mach VM import in the CSRG repository so I don't know how far back they were NOPs, but I doubt any FreeBSD binary uses these. -- John Baldwin