From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Bligh Subject: Re: [PATCH 0/7] Network namespace manipulation with file descriptors Date: Sun, 08 May 2011 13:31:01 +0100 Message-ID: <974CF8842C14240ADB10AD9C@nimrod.local> References: <3A54AB469A0294933EAC2257@nimrod.local> Reply-To: Alex Bligh Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-arch@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Linux Containers , linux-fsdevel@vger.kernel.org, Alex Bligh To: "Eric W. Biederman" Return-path: Received: from mail.avalus.com ([89.16.176.221]:55150 "EHLO mail.avalus.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752559Ab1EHMbH (ORCPT ); Sun, 8 May 2011 08:31:07 -0400 In-Reply-To: Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: Eric, --On 7 May 2011 07:18:44 -0700 "Eric W. Biederman" wrote: > You are essentially describing my setns system call. Great - thanks. >> As a secondary issue, ever without your patch, it would be really >> useful to be able to read from userspace the current network namespace. >> (i.e. the pid concerned, or 1 if not unshared). I would like to >> simply modify a routing daemon's init script so it doesn't start >> if in the host, e.g. at the top: >> [ `cat /proc/.../networknamespace` eq 1 ] && exit 0 > > You can read the processes network namespace by opening > /proc//ns/net. Unfortunately comparing the network > namespaces for identity is another matter. You will probably > be better off simply forcing the routing daemon to start > in the desired network namespace in it's initscript. It's solely a minor convenience issue. The network namespace is unshared by the filing system namespace isn't. So there's an /etc/init.d/bird, which I would like to remain there so I can call it from the network namespace concerned (which doesn't exist at boot time). But I'd also like it not to run at boot time. So it would be useful to me if the script could check whether it is running in the default namespace and refuse to launch if so. I note the /proc/ file you mention is not present in the main tree at the moment. > For purposes of clarity please have a look at my work in > progress patch for iproute2. This demonstrates how I expect > userspace to work in a multi-network namespace world. Will do -- Alex Bligh