Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161108AbWBAQpx (ORCPT ); Wed, 1 Feb 2006 11:45:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161110AbWBAQpw (ORCPT ); Wed, 1 Feb 2006 11:45:52 -0500 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:23969 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S1161108AbWBAQpv (ORCPT ); Wed, 1 Feb 2006 11:45:51 -0500 To: Greg Cc: Linus Torvalds , Hubertus Franke , Dave Hansen , Greg KH , Alan Cox , "Serge E. Hallyn" , Arjan van de Ven , Linux Kernel Mailing List , Cedric Le Goater Subject: Re: RFC [patch 13/34] PID Virtualization Define new task_pid api References: <20060117143258.150807000@sergelap> <20060117143326.283450000@sergelap> <1137511972.3005.33.camel@laptopd505.fenrus.org> <20060117155600.GF20632@sergelap.austin.ibm.com> <1137513818.14135.23.camel@localhost.localdomain> <1137518714.5526.8.camel@localhost.localdomain> <20060118045518.GB7292@kroah.com> <1137601395.7850.9.camel@localhost.localdomain> <43D14578.6060801@watson.ibm.com> <43E0E1D3.5000803@fr.ibm.com> From: ebiederm@xmission.com (Eric W. Biederman) Date: Wed, 01 Feb 2006 09:44:44 -0700 In-Reply-To: <43E0E1D3.5000803@fr.ibm.com> (gkurz@fr.ibm.com's message of "Wed, 01 Feb 2006 17:29:07 +0100") Message-ID: User-Agent: Gnus/5.1007 (Gnus v5.10.7) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1412 Lines: 43 Greg writes: > Eric W. Biederman wrote: >> >> On this front I have been planning on using sys_clone as it allows >> pieces of the virtualization to be incrementally built, it already >> supports the FS namespace, and it supports flexibly specifying what >> you want to contain. >> > > What would you do to handle the following case: > > pid = getpid(); > if (sys_clone(CLONE_CONTAINER) == 0) { > ppid = getppid(); > assert(ppid == pid); > } > > Most of the calls involving resource ids will return values that aren't > *consistent* with ids already stored in userland... could possibly break some > piece of code. Perhaps a sys_exec() should also be enforced to reset the process > memory. Well that assertion will fail. At that point getppid() will return 0, and getpid() will return 1. Processes getting confused is their own problem. Now there will be a pid that the parent sees that will not be 0. And that is what the parent will see in the context of wait. In my code I introduced a wid (wait id) for that purpose. This makes it possible to manage a container using the usual unix process semantics. Which is very important. Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/