From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Van Hensbergen Subject: Re: [PATCH] private mounts Date: Thu, 28 Apr 2005 08:47:44 -0500 Message-ID: References: <20050424205422.GK13052@parcelfarce.linux.theplanet.co.uk> <20050424210616.GM13052@parcelfarce.linux.theplanet.co.uk> <20050424213822.GB9304@mail.shareable.org> <20050425152049.GB2508@elf.ucw.cz> <20050425190734.GB28294@mail.shareable.org> <20050426092924.GA4175@elf.ucw.cz> <20050426140715.GA10833@mail.shareable.org> Reply-To: Eric Van Hensbergen Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Cc: Pavel Machek , Al Viro , Miklos Szeredi , hch@infradead.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@osdl.org Return-path: Received: from wproxy.gmail.com ([64.233.184.194]:21846 "EHLO wproxy.gmail.com") by vger.kernel.org with ESMTP id S262132AbVD1Nrp convert rfc822-to-8bit (ORCPT ); Thu, 28 Apr 2005 09:47:45 -0400 Received: by wproxy.gmail.com with SMTP id 68so643574wri for ; Thu, 28 Apr 2005 06:47:44 -0700 (PDT) To: Jamie Lokier In-Reply-To: <20050426140715.GA10833@mail.shareable.org> Content-Disposition: inline Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On 4/26/05, Jamie Lokier wrote: > > It's called /proc/NNN/root. > > So no new system calls are needed. A daemon to hand out per-user > namespaces (or any other policy) can be written using existing > kernels, and those namespaces can be joined using chroot. > > That's the theory anyway. It's always possible I misread the code (as > I don't use namespaces and don't have tools handy to try them). > Should have checked myself before posting my previous reply -- but this doesn't seem to work. /proc/NNN/root is represented as a symlink, but when you CLONE_NS and then try to look at another one of your process' /proc/NNN/root the link doesn't seem to have a target and you get permission denied on all accesses. I haven't looked at the underlying procfs code, but adapting procfs for this sort of purpose feels wrong. -eric