From mboxrd@z Thu Jan 1 00:00:00 1970 From: "J. Bruce Fields" Subject: Re: [RFC PATCH 0/2] net: connect to UNIX sockets from specified root Date: Mon, 13 Aug 2012 12:47:30 -0400 Message-ID: <20120813164730.GB2497@fieldses.org> References: <20120810125701.7115.71612.stgit@localhost.localdomain> <50254FA6.3060806@zytor.com> <20120810192628.79a34d28@pyramind.ukuu.org.uk> <20120810191149.GA17985@fieldses.org> <20120810202818.06236f46@pyramind.ukuu.org.uk> <50259494.8060304@zytor.com> <5025FA5A.4090403@parallels.com> <50263ECC.4060501@parallels.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Pavel Emelyanov , "H. Peter Anvin" , Alan Cox , "Trond.Myklebust@netapp.com" , "davem@davemloft.net" , "linux-nfs@vger.kernel.org" , "eric.dumazet@gmail.com" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "viro@zeniv.linux.org.uk" , "tim.c.chen@linux.intel.com" , "devel@openvz.org" To: Stanislav Kinsbursky Return-path: Received: from fieldses.org ([174.143.236.118]:32942 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752241Ab2HMQrp (ORCPT ); Mon, 13 Aug 2012 12:47:45 -0400 Content-Disposition: inline In-Reply-To: <50263ECC.4060501@parallels.com> Sender: netdev-owner@vger.kernel.org List-ID: On Sat, Aug 11, 2012 at 03:15:24PM +0400, Stanislav Kinsbursky wrote: > 11.08.2012 10:23, Pavel Emelyanov =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > >On 08/11/2012 03:09 AM, H. Peter Anvin wrote: > >>On 08/10/2012 12:28 PM, Alan Cox wrote: > >>>Explicitly for Linux yes - this is not generally true of the AF_UN= IX > >>>socket domain and even the permissions aspect isn't guaranteed to = be > >>>supported on some BSD environments ! > >>Yes, but let's worry about what the Linux behavior should be. > >> > >>>The name is however just a proxy for the socket itself. You don't = even > >>>get a device node in the usual sense or the same inode in the file= system > >>>space. > >> > >>No, but it is looked up the same way any other inode is (the differ= ence > >>between FIFOs and sockets is that sockets have separate connections= , > >>which is also why open() on sockets would be nice.) > >> > >>However, there is a fundamental difference between AF_UNIX sockets = and > >>open(), and that is how the pathname is delivered. It thus would m= ake > >>more sense to provide the openat()-like information in struct > >>sockaddr_un, but that may be very hard to do in a sensible way. In= that > >>sense it perhaps would be cleaner to be able to do an open[at]() on= the > >>socket node with O_PATH (perhaps there should be an O_SOCKET option= , > >>even?) and pass the resulting file descriptor to bind() or connect(= ). > >I vote for this (openat + O_WHATEVER on a unix socket) as well. It w= ill > >help us in checkpoint-restore, making handling of overmounted/unlink= ed > >sockets much cleaner. >=20 > I have to notice, that it's not enough and doesn't solve the issue. > There should be some way how to connect/bind already existent unix > socket (from kernel, at least), because socket can be created in > user space. > And this way (sock operation or whatever) have to provide an ability > to lookup UNIX socket starting from specified root to support > containers. I don't understand--the rpcbind sockets are created by the kernel. Wha= t am I missing? --b.