From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Waychison Subject: Re: [PATCH] [RFC] c/r: Add UTS support Date: Wed, 18 Mar 2009 17:46:07 -0700 Message-ID: <49C195CF.1080506@google.com> References: <1236880612-15316-1-git-send-email-danms@us.ibm.com> <20090312162954.4a4b8e00@thinkcentre.lan> <87fxhipfrh.fsf@caffeine.danplanet.com> <20090312224820.GA12723@hallyn.com> <87bps6pcyf.fsf@caffeine.danplanet.com> <49C0B069.6060300@cs.columbia.edu> <20090318134932.GC22636@us.ibm.com> <878wn353mf.fsf@caffeine.danplanet.com> <49C1175F.9060600@free.fr> <49C1506C.1080500@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: "Eric W. Biederman" Cc: containers-qjLDD68F18O7TbgM5vRIOg@public.gmane.org, Dan Smith , Nathan Lynch List-Id: containers.vger.kernel.org Eric W. Biederman wrote: > Mike Waychison writes: > >> Cedric Le Goater wrote: >>> Dan Smith wrote: >>>> SH> (Note that in Dan's next version, he did move unshare into >>>> SH> userspace) >>>> >>>> The idealist in me still wants it to be in the kernel. However, after >>>> seeing it done I agree that it's the right thing to do, at least in >>>> this case. >>> I would say in all cases. >>> >>> as you can't unshare(CLONE_NEWPID), >> Eric, >> >> Is there a particular reason the above doesn't work? I made an attempt to >> implement it a while back, but haven't convinced myself that signals and >> re-attaching a new struct pid to a running task is correct. > > Last time I was thinking about this I figured unsharing a pid namespace would > simply place it's children in a different pid namespace, not the originating > process. > > Would that semantic be useful? It would certainly be a lot less effort than > changing the pid on a running process correctly. Hmm, that would be a little odd. I think getting the unsharing task to become pid 1 is a bit easier to understand and it makes it clear which task is the reaper for the new namespace. Otherwise the first child becomes pid 1 but it isn't the reaper.