From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: [RFC][PATCH] ns: Syscalls for better namespace sharing control. Date: Sat, 27 Feb 2010 11:08:35 -0800 Message-ID: References: <4B4F24AC.70105@trash.net> <4B50403A.6010507@trash.net> <1263568754.23480.142.camel@bigi> <1266875729.3673.12.camel@bigi> <1266931623.3973.643.camel@bigi> <1266934817.3973.654.camel@bigi> <1266966581.3973.675.camel@bigi> <4B883987.6090408@parallels.com> <4B883E6F.1060907@parallels.com> <4B88D80A.8010701@parallels.com> <4B88E431.6040609@parallels.com> <4B894564.7080104@parallels.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: hadi@cyberus.ca, Daniel Lezcano , Patrick McHardy , Linux Netdev List , containers@lists.linux-foundation.org, Netfilter Development Mailinglist , Ben Greear , Serge Hallyn , Matt Helsley To: Pavel Emelyanov Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]:56660 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030653Ab0B0TIp (ORCPT ); Sat, 27 Feb 2010 14:08:45 -0500 In-Reply-To: <4B894564.7080104@parallels.com> (Pavel Emelyanov's message of "Sat\, 27 Feb 2010 19\:16\:36 +0300") Sender: netdev-owner@vger.kernel.org List-ID: Pavel Emelyanov writes: > Eric W. Biederman wrote: >> Pavel Emelyanov writes: >> >>> Thanks. What's the problem with setns? >> >> joining a preexisting namespace is roughly the same problem as >> unsharing a namespace. We simply haven't figure out how to do it >> safely for the pid and the uid namespaces. > > The pid may change after this for sure. What problems do you know > about it? What if we try to allocate the same PID in a new space > or return -EBUSY? This will be a good starting point. If we manage > to fix it later this will not break the API at all. Parentage. The pid is the identity of a process and all kinds of things make assumptions in all kinds of strange places. I don't see how waitpid can work if you change the pid. glibc doesn't cope if you change someones pid. >> Definitely. I only consider the current interface to be a mushy not >> set in stone. > > OK. The interface is good. I just don't want you to send it for an inclusion > until we decide what to do with waiting. Sure. I am get a jump on 2.6.35 not aiming for inclusion this merge window. There is plenty of time. > > Poll is OK with me. As far as the notification is concerned - that's also > done in OpenVZ. If you are OK to wait for a week or two I can do it for net > namespaces. Seems reasonable. Eric