From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.kundenserver.de (mout.kundenserver.de [212.227.126.131]) by sourceware.org (Postfix) with ESMTPS id 20EE2386F836 for ; Wed, 27 Jan 2021 13:27:18 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 20EE2386F836 Received: from calimero.vinschen.de ([24.134.7.25]) by mrelayeu.kundenserver.de (mreue009 [212.227.15.167]) with ESMTPSA (Nemesis) id 1MOiLv-1lLTJr3FkN-00Q84j for ; Wed, 27 Jan 2021 14:27:16 +0100 Received: by calimero.vinschen.de (Postfix, from userid 500) id 5729EA80D7F; Wed, 27 Jan 2021 14:27:16 +0100 (CET) Date: Wed, 27 Jan 2021 14:27:16 +0100 From: Corinna Vinschen To: cygwin-patches@cygwin.com Subject: Re: [PATCH] Cygwin: fchmodat: add limited support for AT_SYMLINK_NOFOLLOW Message-ID: <20210127132716.GU4393@calimero.vinschen.de> Reply-To: cygwin-patches@cygwin.com Mail-Followup-To: cygwin-patches@cygwin.com References: <20210126213050.41241-1-kbrown@cornell.edu> <20210127124054.GT4393@calimero.vinschen.de> <5b3fbee6-b80f-1a46-4574-059b9b0c951f@cornell.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5b3fbee6-b80f-1a46-4574-059b9b0c951f@cornell.edu> X-Provags-ID: V03:K1:8SvPm9h48U1cgaV63HuCTyf0m3rP9gSk+CItj+J+zzaBNiC2Fwm GOHQeXiKDLZH1DFh8NwxLl1NgV248sJu8Q0PvTm42fNGQb+SE3IAZl0NWoRHJogxUXBcnsw Vb12HgG3R8kSionDlVfmRg26svJ2Wm606Code0ZsAUj9KiVsx4nD6NelvadSXBHIFCxAD/v w+4gCafrga/KUVseDB36w== X-UI-Out-Filterresults: notjunk:1;V03:K0:w9Ik+AP9Tos=:ZknF03fkddS9u8I6h5UZ9B 3Xzu8vnip3s4XC3HhV8gwCAEMu2hsN5QY+vEQRevSv51WLTGAcyM3qJdOsxLGrcQdAGLx7WxF tKCoRlm4iuR688wjfJcTUaUKewV0pZCiQz7Up9dM9TBEBckodghdWW/6tXDB9ZW5wIlcx2w9f zNT40FnbbZAWktSLZZe5sDau7U4FubZol4joXeQcRT4PNbQ+R824pNpdtdUgPdS6Xs+C5b2e8 qEjwlTsv8Zh/7i1rwX3hTC+Fgh38DJA2Hav5RNh1VXSMwfK0ukPvf6Q1NyTOHSEW5v3VmirwC WxiU4AhC7ufUwNVWx7WkhoNE/MLcYMrQlYsPotRmR/4JaRq5D1FhA0d2i0dbJ/WsBrDWULzzF n3c8WxmxChMvix8RBKiLyN0pWSWejBAtyg+0+f7WIFGD7VxXwrwMRfTllGe4tXdIbjpnI1Aiv XbHbpu8yPQ== X-Spam-Status: No, score=-101.2 required=5.0 tests=BAYES_00, GOOD_FROM_CORINNA_CYGWIN, KAM_DMARC_NONE, KAM_DMARC_STATUS, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NEUTRAL, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: cygwin-patches@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Cygwin core component patch submission and discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Jan 2021 13:27:19 -0000 On Jan 27 08:22, Ken Brown via Cygwin-patches wrote: > On 1/27/2021 7:40 AM, Corinna Vinschen via Cygwin-patches wrote: > > On Jan 26 16:30, Ken Brown via Cygwin-patches wrote: > > > Allow fchmodat with the AT_SYMLINK_NOFOLLOW flag to succeed on > > > non-symlinks. Previously it always failed, as it does on Linux. But > > > POSIX permits it to succeed on non-symlinks even if it fails on > > > symlinks. > > > > > > The reason for following POSIX rather than Linux is to make gnulib > > > report that fchmodat works on Cygwin. This improves the efficiency of > > > packages like GNU tar that use gnulib's fchmodat module. Previously > > > such packages would use a gnulib replacement for fchmodat on Cygwin. > > > > Wait, what? So if Cygwin behaves like Linux, gnulib treats fchmodat > > as non-working? So what does gnulib do on a Linux system? Does it > > use its own fchmodat there, too? > > Apparently so. Here's a comment from gnulib's test program for fchmodat: > > /* Test whether fchmodat+AT_SYMLINK_NOFOLLOW works on non-symlinks. > This test fails on GNU/Linux with glibc 2.31 (but not on > GNU/kFreeBSD nor GNU/Hurd) and Cygwin 2.9. */ > > I agree that it's strange. ¯\_(ツ)_/¯ Corinna