From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael Kerrisk (man-pages)" Subject: Re: Edited seccomp.2 man page for review [v2] Date: Wed, 07 Jan 2015 12:53:27 +0100 Message-ID: <54AD1E37.8020509@gmail.com> References: <54A29722.1010901@gmail.com> <54A300D0.7090802@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Kees Cook Cc: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, Daniel Borkmann , Linux API , "linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , lkml , Will Drewry List-Id: linux-api@vger.kernel.org Hi Kees, On 01/05/2015 09:25 PM, Kees Cook wrote: > On Tue, Dec 30, 2014 at 11:45 AM, Michael Kerrisk (man-pages) > wrote: >>>> The program counter will be as though the system call happened >>>> (i.e., it will not point to the system call instruction). >>>> The return value register will contain an architecture\-dependent value; >>>> if resuming execution, set it to something sensible. >>>> .\" FIXME Regarding the preceding line, can you give an example(s) >>>> .\" of "something sensible"? (Depending on the answer, maybe it >>>> .\" might be useful to add some text on this point.) >>> >>> This means sensible in the context of the syscall made, or the desired >>> behavior. For example, setting the return value to ELOOP for something >>> like a "bind" syscall isn't very sensible. >> >> Okay -- I did s/sensible/appropriate for the system call/ > > Yes, perfect. That captures it nicely. Okay. >>>> .\" >>>> .\" FIXME Please check: >>>> .\" In an attempt to make the text clearer, I changed >>>> .\" "replacing it with" to "setting the return value register to" >>>> .\" Okay? >>>> (The architecture dependency is because setting the return value register to >>>> .BR ENOSYS >>>> could overwrite some useful information.) >>> >>> Well, the arch dependency is really because _how_ to change the >>> register, and the register itself, is different between architectures. >>> (i.e. which ptrace call is needed, and which register is being >>> changed.) The overwriting of useful information is certainly true too, >>> though. >> >> So, revert to the previous wording? Or do you have a suggested >> better wording? > > I think the previous wording is better. I'm struggling to produce > language that makes more sense here. Okay -- reverted. >> Thanks. We're getting close now. > > Excellent! :) Still hoping to hear from Will Drewy regarding this FIXME in the page source: .\" FIXME What is the significance of the line .\" ftest->code = BPF_LDX | BPF_W | BPF_ABS; .\" in kernel/seccomp.c::seccomp_check_filter()? Do you know if he's about? Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/