From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: util-linux-owner@vger.kernel.org Received: from mx1.redhat.com ([209.132.183.28]:34598 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753148AbbAFRWB (ORCPT ); Tue, 6 Jan 2015 12:22:01 -0500 Date: Tue, 6 Jan 2015 18:21:34 +0100 From: Karel Zak To: "Eric W. Biederman" Cc: Lubomir Rintel , util-linux@vger.kernel.org, Mikhail Gusarov Subject: Re: [PATCH 2/2] unshare: allow persisting namespaces Message-ID: <20150106172134.GJ18528@x2.net.home> References: <1419798218-3174-1-git-send-email-lkundrak@v3.sk> <1419798218-3174-2-git-send-email-lkundrak@v3.sk> <20150106130343.GG18528@x2.net.home> <87y4pfomui.fsf@x220.int.ebiederm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <87y4pfomui.fsf@x220.int.ebiederm.org> Sender: util-linux-owner@vger.kernel.org List-ID: On Tue, Jan 06, 2015 at 11:11:49AM -0600, Eric W. Biederman wrote: > No. An empty pid namespace is valid. An empty pid namespace is one > in which an init process has not entered the pid namespace, or one in but if I create a PID namespace (unshare/clone) then then I'm the init process.... how I can create empty PID namespace (from userspace)? > which the init process has exited (and thus no more processes are > allowed). yes, this makes sense > So an empty pid namespace is a little weird but valid. > > The implementation details of the patch completely baffle me. I can't > see a reason for things being implemented with clone for example. Yes, this part of the patch is strange, but I like the basic idea of the patch -- so make it possible to create an empty namespace and then later enter by nsenter. Karel -- Karel Zak http://karelzak.blogspot.com