From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp1 ([2001:41d0:2:bcc0::]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) by ms0.migadu.com with LMTPS id +L5YCR/HeGAYsgAAgWs5BA (envelope-from ) for ; Fri, 16 Apr 2021 01:07:11 +0200 Received: from aspmx1.migadu.com ([2001:41d0:2:bcc0::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp1 with LMTPS id oAcZAx/HeGAUPwAAbx9fmQ (envelope-from ) for ; Thu, 15 Apr 2021 23:07:11 +0000 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by aspmx1.migadu.com (Postfix) with ESMTPS id 769FCDB80 for ; Fri, 16 Apr 2021 01:07:10 +0200 (CEST) Received: from localhost ([::1]:57312 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lXB4m-00048p-Kw for larch@yhetil.org; Thu, 15 Apr 2021 19:07:08 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58950) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lXB4g-00048h-LS for bug-guix@gnu.org; Thu, 15 Apr 2021 19:07:02 -0400 Received: from debbugs.gnu.org ([209.51.188.43]:56210) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lXB4g-00068k-Ex for bug-guix@gnu.org; Thu, 15 Apr 2021 19:07:02 -0400 Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1lXB4g-00052y-AQ for bug-guix@gnu.org; Thu, 15 Apr 2021 19:07:02 -0400 X-Loop: help-debbugs@gnu.org Subject: bug#36508: GDM files have incorrect owner after temporarily removing service Resent-From: Mark H Weaver Original-Sender: "Debbugs-submit" Resent-CC: bug-guix@gnu.org Resent-Date: Thu, 15 Apr 2021 23:07:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 36508 X-GNU-PR-Package: guix X-GNU-PR-Keywords: To: Ludovic =?UTF-8?Q?Court=C3=A8s?= Received: via spool by 36508-submit@debbugs.gnu.org id=B36508.161852798419354 (code B ref 36508); Thu, 15 Apr 2021 23:07:02 +0000 Received: (at 36508) by debbugs.gnu.org; 15 Apr 2021 23:06:24 +0000 Received: from localhost ([127.0.0.1]:39523 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lXB44-000525-MT for submit@debbugs.gnu.org; Thu, 15 Apr 2021 19:06:24 -0400 Received: from world.peace.net ([64.112.178.59]:41330) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lXB41-00051o-38 for 36508@debbugs.gnu.org; Thu, 15 Apr 2021 19:06:24 -0400 Received: from mhw by world.peace.net with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lXB3u-0002Zm-Ox; Thu, 15 Apr 2021 19:06:14 -0400 From: Mark H Weaver In-Reply-To: <878s5j8ga7.fsf@gnu.org> References: <20190705083620.lbzu7a33awbymh3d@cf0> <1576552162.14721.1618320275616@office.mailbox.org> <87czuxsya5.fsf@netris.org> <875z0pgnqn.fsf@gnu.org> <87lf9jiems.fsf@netris.org> <878s5j8ga7.fsf@gnu.org> Date: Thu, 15 Apr 2021 19:04:30 -0400 Message-ID: <87wnt3gndy.fsf@netris.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-guix@gnu.org List-Id: Bug reports for GNU Guix List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Brendan Tildesley , 36508@debbugs.gnu.org Errors-To: bug-guix-bounces+larch=yhetil.org@gnu.org Sender: "bug-Guix" X-Migadu-Flow: FLOW_IN ARC-Message-Signature: i=1; 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aspmx1.migadu.com; dkim=none; dmarc=none; spf=pass (aspmx1.migadu.com: domain of bug-guix-bounces@gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=bug-guix-bounces@gnu.org X-Migadu-Spam-Score: -2.44 Authentication-Results: aspmx1.migadu.com; dkim=none; dmarc=none; spf=pass (aspmx1.migadu.com: domain of bug-guix-bounces@gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=bug-guix-bounces@gnu.org X-Migadu-Queue-Id: 769FCDB80 X-Spam-Score: -2.44 X-Migadu-Scanner: scn0.migadu.com X-TUID: BfnAlnTDQ308 Hi Ludovic, Ludovic Court=C3=A8s writes: > IDs as hash of the user names are interesting because that=E2=80=99d be > stateless (conversely, the current ID allocation strategy is stateful: > it arranges to not reuse recently-freed IDs.) > > But like you write, we=E2=80=99d need 32-bit UIDs. In libc, =E2=80=98uid= _t=E2=80=99 > (specifically =E2=80=98__UID_T_TYPE=E2=80=99 in typesizes.h) is 32-bit, s= o it might work > rather well in user space. The kernel and core system components certainly support 32-bit UIDs, and have for around 20 years. > It still sounds like a change with significant implications though, and > it=E2=80=99s hard to predict exactly how it would go or what would break. Right, my concern is with the vast majority of programs and libraries in Guix, most of which probably haven't seen much (if any) testing with large UIDs. > For example, that does away with the system/non-system ranges, and > wouldn=E2=80=99t play well with =E2=80=9Cspecial=E2=80=9D IDs like 0 and = 65535. This particular issue is easily addressed. It's easy enough to find a function from 31-hash values to 32-bit IDs that's injective and avoids any chosen subset of special IDs, as long as there are fewer than 2^31 special IDs. Simply adding 65536 (or even 2^31) to the hash value would be one easy option. What do you think? Mark