Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751085AbWHXKn6 (ORCPT ); Thu, 24 Aug 2006 06:43:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751096AbWHXKn6 (ORCPT ); Thu, 24 Aug 2006 06:43:58 -0400 Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:57222 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S1751085AbWHXKn5 (ORCPT ); Thu, 24 Aug 2006 06:43:57 -0400 Subject: Re: [PATCH 4/6] BC: user interface (syscalls) From: Alan Cox To: Andrew Morton Cc: Kirill Korotaev , Linux Kernel Mailing List , Christoph Hellwig , Pavel Emelianov , Andrey Savochkin , devel@openvz.org, Rik van Riel , Andi Kleen , Greg KH , Oleg Nesterov , Matt Helsley , Rohit Seth , Chandra Seetharaman In-Reply-To: <20060823213512.88f4344d.akpm@osdl.org> References: <44EC31FB.2050002@sw.ru> <44EC369D.9050303@sw.ru> <44EC5B74.2040104@sw.ru> <20060823095031.cb14cc52.akpm@osdl.org> <1156354182.3007.37.camel@localhost.localdomain> <20060823213512.88f4344d.akpm@osdl.org> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Thu, 24 Aug 2006 12:04:16 +0100 Message-Id: <1156417456.3007.72.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.2 (2.6.2-1.fc5.5) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1231 Lines: 31 Ar Mer, 2006-08-23 am 21:35 -0700, ysgrifennodd Andrew Morton: > > Its a uid_t because of setluid() and twenty odd years of existing unix > > practice. > > > > I don't understand. This number is an identifier for an accounting > container, which was somehow dreamed up by userspace. Which happens to be a uid_t. It could easily be anyother_t of itself and you can create a container_id_t or whatever. It is just a number. The ancient Unix implementations of this kind of resource management and security are built around setluid() which sets a uid value that cannot be changed again and is normally used for security purposes. That happened to be a uid_t and in simple setups at login uid = luid = euid would be the norm. Thus the Linux one happens to be a uid_t. It could be something else but for the "container per user" model whatever a container is must be able to hold all possible uid_t values. So we can certainly do something like typedef uid_t container_id_t; Alan - 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/