Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269382AbUINS5O (ORCPT ); Tue, 14 Sep 2004 14:57:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269439AbUINSzk (ORCPT ); Tue, 14 Sep 2004 14:55:40 -0400 Received: from mail2.bluewin.ch ([195.186.4.73]:9913 "EHLO mail2.bluewin.ch") by vger.kernel.org with ESMTP id S269366AbUINSxt (ORCPT ); Tue, 14 Sep 2004 14:53:49 -0400 Date: Tue, 14 Sep 2004 20:45:18 +0200 From: Roger Luethi To: William Lee Irwin III Cc: Albert Cahalan , Stephen Smalley , Andrew Morton OSDL , lkml , Albert Cahalan , Paul Jackson , James Morris , Chris Wright Subject: Re: [1/1][PATCH] nproc v2: netlink access to /proc information Message-ID: <20040914184517.GA2655@k3.hellgate.ch> Mail-Followup-To: William Lee Irwin III , Albert Cahalan , Stephen Smalley , Andrew Morton OSDL , lkml , Albert Cahalan , Paul Jackson , James Morris , Chris Wright References: <20040914064403.GB20929@k3.hellgate.ch> <20040914071058.GH9106@holomorphy.com> <20040914075508.GA10880@k3.hellgate.ch> <20040914080132.GJ9106@holomorphy.com> <20040914092748.GA11238@k3.hellgate.ch> <20040914153758.GO9106@holomorphy.com> <20040914160150.GB13978@k3.hellgate.ch> <20040914163712.GT9106@holomorphy.com> <20040914171525.GA14031@k3.hellgate.ch> <20040914174325.GX9106@holomorphy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040914174325.GX9106@holomorphy.com> X-Operating-System: Linux 2.6.8 on i686 X-GPG-Fingerprint: 92 F4 DC 20 57 46 7B 95 24 4E 9E E7 5A 54 DC 1B X-GPG: 1024/80E744BD wwwkeys.ch.pgp.net User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2079 Lines: 40 On Tue, 14 Sep 2004 10:43:25 -0700, William Lee Irwin III wrote: > On Tue, 14 Sep 2004 09:37:12 -0700, William Lee Irwin III wrote: > >> Not particularly. It largely means poorly-coded apps may report gibberish. > > On Tue, Sep 14, 2004 at 07:15:25PM +0200, Roger Luethi wrote: > > If we are still talking about the same thing here, gibberish is a rather > > strong word. In the design I proposed access control affects the subset > > of tasks returned as a result -- the tool would still display meaningful > > information for the tasks it got replies for. > > That sounds bizarre. I'd expect some kind of reply, even if merely an > error. I suppose "no reply" could be interpreted as "ESRCH", though > this means distinguishing between "some field caused an error" and > "the thing is dead" means the app has to fall back to requesting fields > one at a time. I suppose you are thinking of a request that lists a number of PIDs along with a number of field IDs. In that case yes, I agree that it makes sense to provide some explicit feedback to the tool once we add access control (before that, there is no ambiguity: a missing answer means ESRCH). The most common request, though, won't provide a list of pids, it will only provide a list of field IDs and select all processes in the system (NPROC_SELECT_ALL). There is no ambiguity here, either: The tool didn't ask for any specific process to begin with, ESRCH doesn't make sense here. And for a system that looks anything like /proc does today, fields that are capable of triggering EPERM are few and far between, certainly not something you are hitting unexpectedly in the fast path of a process monitoring tool. Thanks, by the way, for all the feedback that helped me realize that I have so far failed to explain the design well enough. I will try to work on that. Roger - 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/