From owner-freebsd-hackers@freebsd.org Thu May 14 20:30:31 2020 Return-Path: <owner-freebsd-hackers@freebsd.org> Delivered-To: freebsd-hackers@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id C2F7C2DE80A for <freebsd-hackers@mailman.nyi.freebsd.org>; Thu, 14 May 2020 20:30:31 +0000 (UTC) (envelope-from phk@critter.freebsd.dk) Received: from mailman.nyi.freebsd.org (mailman.nyi.freebsd.org [IPv6:2610:1c1:1:606c::50:13]) by mx1.freebsd.org (Postfix) with ESMTP id 49NNTL4XvHz3P2W for <freebsd-hackers@freebsd.org>; Thu, 14 May 2020 20:30:30 +0000 (UTC) (envelope-from phk@critter.freebsd.dk) Received: by mailman.nyi.freebsd.org (Postfix) id 9BB912DE807; Thu, 14 May 2020 20:30:30 +0000 (UTC) Delivered-To: hackers@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 9B6B92DE806; Thu, 14 May 2020 20:30:30 +0000 (UTC) (envelope-from phk@critter.freebsd.dk) Received: from phk.freebsd.dk (phk.freebsd.dk [130.225.244.222]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 49NNTL38M2z3P2V; Thu, 14 May 2020 20:30:29 +0000 (UTC) (envelope-from phk@critter.freebsd.dk) Received: from critter.freebsd.dk (v-critter.freebsd.dk [192.168.55.3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by phk.freebsd.dk (Postfix) with ESMTPS id A1E181AF18C; Thu, 14 May 2020 20:30:27 +0000 (UTC) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.15.2/8.15.2) with ESMTPS id 04EKURnS033551 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Thu, 14 May 2020 20:30:27 GMT (envelope-from phk@critter.freebsd.dk) Received: (from phk@localhost) by critter.freebsd.dk (8.15.2/8.15.2/Submit) id 04EKUQmj033550; Thu, 14 May 2020 20:30:26 GMT (envelope-from phk) To: Alan Somers <asomers@freebsd.org> cc: "Julian H. Stacey" <jhs@berklix.com>, Kyle Evans <kevans@freebsd.org>, "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org>, "freebsd-hackers@freebsd.org" <hackers@freebsd.org> Subject: Re: [HEADSUP] Disallowing read() of a directory fd In-reply-to: <CAOtMX2i2Z-KX=3rYR2nZ1g1Lb_tF==H3xPKcQMBxJs1Kqr-meQ@mail.gmail.com> From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> References: <CACNAnaFszg+QWPRS0kghsnQMxXc+5niPTTNiUPSmK60YyBGCzA@mail.gmail.com> <202005142017.04EKH0aA093503@fire.js.berklix.net> <CAOtMX2i2Z-KX=3rYR2nZ1g1Lb_tF==H3xPKcQMBxJs1Kqr-meQ@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <33548.1589488226.1@critter.freebsd.dk> Content-Transfer-Encoding: quoted-printable Date: Thu, 14 May 2020 20:30:26 +0000 Message-ID: <33549.1589488226@critter.freebsd.dk> X-Rspamd-Queue-Id: 49NNTL38M2z3P2V X-Spamd-Bar: ----- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-5.96 / 15.00]; NEURAL_HAM_MEDIUM(-0.96)[-0.964,0]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; REPLY(-4.00)[] X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Technical Discussions relating to FreeBSD <freebsd-hackers.freebsd.org> List-Unsubscribe: <https://lists.freebsd.org/mailman/options/freebsd-hackers>, <mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers/> List-Post: <mailto:freebsd-hackers@freebsd.org> List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help> List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, <mailto:freebsd-hackers-request@freebsd.org?subject=subscribe> X-List-Received-Date: Thu, 14 May 2020 20:30:31 -0000 -------- In message <CAOtMX2i2Z-KX=3D3rYR2nZ1g1Lb_tF=3D=3DH3xPKcQMBxJs1Kqr-meQ@mail= .gmail.com> , Alan Somers writes: >Really? When is that occasionally useful? I've never seen anything usef= ul >come out of reading a directory. Two things I have done over the years: Figure out which filenames prevent a enormous but sparse directory from being compacted. Figure out which control characters were in a filename. It might be a good idea to add a override flag on this feature, along the lines of: kern.geom.debugflags=3D0x10 -- = Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe = Never attribute to malice what can adequately be explained by incompetence= .