From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753150AbbAPS0E (ORCPT ); Fri, 16 Jan 2015 13:26:04 -0500 Received: from mail-we0-f173.google.com ([74.125.82.173]:63451 "EHLO mail-we0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751502AbbAPS0C (ORCPT ); Fri, 16 Jan 2015 13:26:02 -0500 Message-ID: <54B957B5.8000202@gmail.com> Date: Fri, 16 Jan 2015 19:25:57 +0100 From: Piotr Karbowski User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Al Viro CC: linux-kernel@vger.kernel.org Subject: Re: [BUG] rename() from outside of the target dir breaks /proc exe symlink. References: <549EEEEA.1050306@gmail.com> <20141227181412.GG22149@ZenIV.linux.org.uk> <54A329C1.9030704@gmail.com> In-Reply-To: <54A329C1.9030704@gmail.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/30/2014 11:40 PM, Piotr Karbowski wrote: > Hi Al, > > On 12/27/2014 07:14 PM, Al Viro wrote: >> That's because it never _had_ worked. Note that opening the damn thing >> will give the right file - it does not work by traversing the result of >> readlink(2). readlink(2) output on those is not promised to be useful >> in all cases; often enough it is, but it won't work on cross-directory >> renames, it can't be used to tell a filename that really ends with " >> (deleted)" >> from a removed file, etc. Moreover, it only very recently became >> usable for >> victim names with the last component longer than 40 characters if you >> did an >> overwriting rename. >> >> What are you trying to use it for? > > I am using it to track the origin of running processes. I am working > with continuous integration of a Linux embedded software. The tests goes > in Linux containers, multiple instances of binary with the same name in > a single container/namespace, all with cwd symlink pointing to / which > looks from outside virtually the same, the binaries are modified at > runtime by coping, modifing and replacing for another execution of the > same binary (using patchelf to add additional NEEDED to header or change > rpath or dynamic loader and such). > > In my very usecase, the exe symlink is essential. *Friendly bump* Can anything be done about it or is there any other mechanism that I could use to get origin of the running binary? -- Piotr.