From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751062AbVHVUaL (ORCPT ); Mon, 22 Aug 2005 16:30:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751069AbVHVUaL (ORCPT ); Mon, 22 Aug 2005 16:30:11 -0400 Received: from embla.aitel.hist.no ([158.38.50.22]:17625 "HELO embla.aitel.hist.no") by vger.kernel.org with SMTP id S1751062AbVHVUaK (ORCPT ); Mon, 22 Aug 2005 16:30:10 -0400 Date: Mon, 22 Aug 2005 22:38:05 +0200 To: Guillermo =?iso-8859-1?Q?L=F3pez?= Alejos Cc: Linh Dang , linux-kernel@vger.kernel.org Subject: Re: Environment variables inside the kernel? Message-ID: <20050822203805.GA29754@aitel.hist.no> References: <4fec73ca050818084467f04c31@mail.gmail.com> <4fec73ca05081811488ec518e@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4fec73ca05081811488ec518e@mail.gmail.com> User-Agent: Mutt/1.5.9i From: Helge Hafting Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 18, 2005 at 08:48:04PM +0200, Guillermo López Alejos wrote: > Whoa!, I did not expect so many replies. Thank you for your answers. > > The thing is that the Computer Architecture area of the University I > am studying at is developing a parallel filesystem. Currently it works > as a stand-alone program (this is why it uses resources like > environment variables), and I have been told to integrate it in the > Linux kernel. > > I have to justify changes on this filesystem code (like avoiding the > use of environment variables) to my tutor. In this case I needed to > find why it is not possible to use environment variables in kernel > space. > > I was looking for a reference documentation which give a definition of > environment variables that exclude their use inside the kernel, or, > simply, I expected to find a design decision to justify this. But I > think I have enough information with your answers, I will be able to > elaborate a satisfactory conclusion. > > Excuse me if the topic was so obvious (it was not to me) and thank you again, It is obvious to someone who knows what the kernel is. A kernel and a process is very different things. A comparison to something different: A book always have a "page 1". It is usually only the title, so it is a nice place for writing some notes as well. (similiar to how a process have an environment.) A library is a big collection of books, (similiar to how the kernel manages a collection of processes.) Still, it does not make sense at all to talk about "page 1 of the library!" Even if it _is_ useful to write some library-specific notes somewhere. The kernel does not have an environment of its own. It manages all the processes, and jave equal access all of the environmnts (albeit in a hackish way only) for process envirnments are _not_ part of the kernel/process communication interface. |1 Helge Hafting