From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from NAM12-DM6-obe.outbound.protection.outlook.com (mail-dm6nam12on2127.outbound.protection.outlook.com [40.107.243.127]) by sourceware.org (Postfix) with ESMTPS id 2F2EF3858022 for ; Wed, 27 Jan 2021 13:22:57 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 2F2EF3858022 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Bqa0rU/4XgpPLcqyFCydfsBEZ7KxlUFm4PP2+17opaww+nZm7gUYg5stcyuaSbWYqq2h6mJNbshep2nr4UqQdmPsWGQw3m5ETcShPya+S4W4dxayoAwU5zWUx3dzcwt3AycvQfEC0NMB87xszcoT5c2EJeNHU0kCIqd77qTL5ibW57Xz+qCcglXLlfZ7/NtOvLoczsWmSCEdFz9pJt4hrqhsVQ+ss60FHkTG6/1RNe+WHyrnqf2GXnSkCyzebThanu6Dh60obLmbsw3L/V8wfsLl4zE5lkeVfsXs8WR8lIWwUcYhS9HZ+JnCcVixT3xrp/LEX4nRZ1r+kv5cLJ79/w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=AgmL8GbmoYd/PBUoL76F58teOL2TEnmNzGp1WpIsxyI=; b=IsesGuGEDl5jla4aPWkT+RMlSRycIWaSgrTp5XoUNFi5V6qOgCDVyxXgdduoRjZP03DI1NV569R65ftnBD9O24UMTejzaOvlPipuP06vk/TWT8/V4Y1RF0FZquhtaJ5ILGgu54anf8Cc5uJ50D6SQfWjtvnxJE7kjZli64glOUjwS5kKQVkDT2Bh5U72GeaKJvzeaEH1GEByPiq95B0fr7tHeflcJbK8UKZA1ijyTEg2HNOQxkjwLY4vxHk0N0EFPdf+54oKHf3qrTH3mBmDZDLLs7zP18w1n54sJ4HuNeHAuwKbjlQMxfFPse8kmNx+iBriuADtIhOlo7/1L5GuBA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=cornell.edu; dmarc=pass action=none header.from=cornell.edu; dkim=pass header.d=cornell.edu; arc=none Received: from BN7PR04MB4388.namprd04.prod.outlook.com (2603:10b6:406:f8::19) by BN6PR04MB0660.namprd04.prod.outlook.com (2603:10b6:404:d9::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3784.13; Wed, 27 Jan 2021 13:22:55 +0000 Received: from BN7PR04MB4388.namprd04.prod.outlook.com ([fe80::f071:e174:ef12:375c]) by BN7PR04MB4388.namprd04.prod.outlook.com ([fe80::f071:e174:ef12:375c%6]) with mapi id 15.20.3784.017; Wed, 27 Jan 2021 13:22:55 +0000 Subject: Re: [PATCH] Cygwin: fchmodat: add limited support for AT_SYMLINK_NOFOLLOW To: cygwin-patches@cygwin.com References: <20210126213050.41241-1-kbrown@cornell.edu> <20210127124054.GT4393@calimero.vinschen.de> From: Ken Brown Message-ID: <5b3fbee6-b80f-1a46-4574-059b9b0c951f@cornell.edu> Date: Wed, 27 Jan 2021 08:22:53 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 In-Reply-To: <20210127124054.GT4393@calimero.vinschen.de> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [65.112.130.200] X-ClientProxiedBy: BN6PR03CA0112.namprd03.prod.outlook.com (2603:10b6:404:10::26) To BN7PR04MB4388.namprd04.prod.outlook.com (2603:10b6:406:f8::19) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [10.13.22.4] (65.112.130.200) by BN6PR03CA0112.namprd03.prod.outlook.com (2603:10b6:404:10::26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3805.16 via Frontend Transport; Wed, 27 Jan 2021 13:22:55 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 31b14842-66af-4e6f-b508-08d8c2c6a83b X-MS-TrafficTypeDiagnostic: BN6PR04MB0660: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:7219; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:BN7PR04MB4388.namprd04.prod.outlook.com; PTR:; CAT:NONE; SFS:(4636009)(136003)(376002)(396003)(346002)(366004)(39860400002)(31686004)(2616005)(6916009)(6486002)(786003)(31696002)(316002)(86362001)(956004)(5660300002)(52116002)(75432002)(53546011)(16576012)(8936002)(66476007)(36756003)(66946007)(66556008)(8676002)(478600001)(2906002)(186003)(26005)(16526019)(45980500001)(43740500002); DIR:OUT; SFP:1102; X-MS-Exchange-AntiSpam-MessageData: =?Windows-1252?Q?spt5GWTERychSOZRcXHhCLR0DpXBc/xnkXq8Uqr0z62HSvlqAi5qDLgX?= =?Windows-1252?Q?NNBL2bbomLKyvKH8zWCnUEnww2EaxWYMU7OnXgoQWAvC8iD2ANZ5J44S?= =?Windows-1252?Q?7PzFwR5iig/rqpWZwFpdql6NX8IoZTL55/Zwu/EAltFD4mTjHSlZWXq4?= =?Windows-1252?Q?Q9aKKXEgKX3+7O0IwEmnnTIn5TDDhBEI3AyMvl0JZcA67QWeME/p5RZe?= =?Windows-1252?Q?ncLB2RMDKYB9k/Cf8NMQ9IrVguicwTkXDj3YWFVsY32rAg29PgYvCIJo?= =?Windows-1252?Q?fQS76y/Ea/8oJ2jb0Y1ha7DEY9qk0CzAGtNePdhGivcBGKK9lBQymTWJ?= =?Windows-1252?Q?UW1kRvug6z29Lfg4SJuiJ0B2n3mexEMTf6fGVkeN5+ncu4fZ/5eyjHKy?= =?Windows-1252?Q?jsPUcIppje/Xg/2Xt7MGAzAVrJoB1//fxnjsky6nBtGSu/kOOMdvXZpU?= =?Windows-1252?Q?eMlCVLMInVumzeOBw/H/YEzTaUjIDuiNAnWDq3YBp8Uh4q67A2zGXM4Q?= =?Windows-1252?Q?T3bZ2uFF7IBjXxDxt5C6K9yhZGYmbk0yWnT2ZYsKvOkh6AmI0VmUjPCT?= =?Windows-1252?Q?9yS/tW4wOEKPHbs/c9jgi5RQoTU4SNPeaTuVAxTWNfZZ3kzJ5o6wnXES?= =?Windows-1252?Q?q5/YCN/IOU3Q2bOUmupCknbrEpCBSX8Sq6ug48Z4MeX4qGLC1ApG5/CY?= =?Windows-1252?Q?TZdHZ+ZTmxuHfByJk5F2yWeYoQHU92HSZxMmlzJguMbG/hK3jbEBxuHB?= =?Windows-1252?Q?f6xSGk/a4jlEdqaftr+NsIFYJ769JmpL0W2Q4iq0JWMuOMzPiO+TGgex?= =?Windows-1252?Q?9ZFx86Ls54a7GYwSg2GbyBJFEyNyVHbRd4Fc/F2MQ8BKPxA5LFKzyCo9?= =?Windows-1252?Q?fTRpyNCEorUUp3gqeC3K/y0V2BkdEftAZZ/hE7vvdiV9W1c0kXM4gPtK?= =?Windows-1252?Q?8sfEIq1Bua81nhf/frY/ihL99B3v4VZAGJaQbKW/4R9l9t/EklC9w4ns?= =?Windows-1252?Q?kVhfNbAjnWal1C39OpxBmteq6moMc/ZFodvMqxxwYoahYXXehl3CDWZL?= =?Windows-1252?Q?WD97P9lXg1+0lviIDpuuo/14fuxWvr2SBxGMlmdeJU3gqAJgDH42WePF?= =?Windows-1252?Q?TsalrEa94N3YoONtCv5VEXzB?= X-OriginatorOrg: cornell.edu X-MS-Exchange-CrossTenant-Network-Message-Id: 31b14842-66af-4e6f-b508-08d8c2c6a83b X-MS-Exchange-CrossTenant-AuthSource: BN7PR04MB4388.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Jan 2021 13:22:55.5742 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 5d7e4366-1b9b-45cf-8e79-b14b27df46e1 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 0OwBYT+Qp2G0MGGcu1kLJ7cJAVIqSIiJDkrorAQsJ+BImQ4WikEopBjQMJ/ZW4CbCHgr0IP8qYPdqFEzKI+J/g== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN6PR04MB0660 X-Spam-Status: No, score=-3.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, MSGID_FROM_MTA_HEADER, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_PASS, SPF_PASS, 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 13:22:58 -0000 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. Ken