From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F14C5C3F2D1 for ; Mon, 2 Mar 2020 12:55:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C73A8217F4 for ; Mon, 2 Mar 2020 12:55:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727883AbgCBMze (ORCPT ); Mon, 2 Mar 2020 07:55:34 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:56364 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727173AbgCBMze (ORCPT ); Mon, 2 Mar 2020 07:55:34 -0500 Received: from ip5f5bf7ec.dynamic.kabel-deutschland.de ([95.91.247.236] helo=wittgenstein) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1j8kbc-0005MT-1m; Mon, 02 Mar 2020 12:55:32 +0000 Date: Mon, 2 Mar 2020 13:55:31 +0100 From: Christian Brauner To: Florian Weimer Cc: David Howells , linux-api@vger.kernel.org, viro@zeniv.linux.org.uk, metze@samba.org, torvalds@linux-foundation.org, cyphar@cyphar.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Have RESOLVE_* flags superseded AT_* flags for new syscalls? Message-ID: <20200302125531.7z2viveb3zxhqkuj@wittgenstein> References: <96563.1582901612@warthog.procyon.org.uk> <20200228152427.rv3crd7akwdhta2r@wittgenstein> <87h7z7ngd4.fsf@oldenburg2.str.redhat.com> <20200302115239.pcxvej3szmricxzu@wittgenstein> <8736arnel9.fsf@oldenburg2.str.redhat.com> <20200302121959.it3iophjavbhtoyp@wittgenstein> <20200302123510.bm3a2zssohwvkaa4@wittgenstein> <87y2sjlygl.fsf@oldenburg2.str.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <87y2sjlygl.fsf@oldenburg2.str.redhat.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 02, 2020 at 01:42:50PM +0100, Florian Weimer wrote: > * Christian Brauner: > > > One difference to openat() is that openat2() doesn't silently ignore > > unknown flags. But I'm not sure that would matter for iplementing > > openat() via openat2() since there are no flags that openat() knows about > > that openat2() doesn't know about afaict. So the only risks would be > > programs that accidently have a bit set that isn't used yet. > > Will there be any new flags for openat in the future? If not, we can > just use a constant mask in an openat2-based implementation of openat. >From past experiences with other syscalls I would expect that any new features would only be available through openat2(). The way I see it in general is that a revised version of a syscall basically deprecates the old syscall _wrt to new features_, i.e. new features will only be available through the revised version unless there are very strong reasons to also allow it in the old version (security bug or whatever). (But I don't want to be presumptuous here and pretend I can make any definiteve statement. Ultimately it's up to the community, I guess. :)) Christian