From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Emelyanov Subject: Re: [RFC PATCH 0/2] net: connect to UNIX sockets from specified root Date: Sat, 11 Aug 2012 10:23:22 +0400 Message-ID: <5025FA5A.4090403@parallels.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: "J. Bruce Fields" , "Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org" , "davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org" , "linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org" , "netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org" , "tim.c.chen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org" , "devel-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org" To: "H. Peter Anvin" , Alan Cox , Stanislav Kinsbursky Return-path: In-Reply-To: <50259494.8060304-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org> Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org 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_UNIX >> 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 difference > 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 make > 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 will help us in checkpoint-restore, making handling of overmounted/unlinked sockets much cleaner. > -hpa Thanks, Pavel -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html