From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from NAM02-BL2-obe.outbound.protection.outlook.com (mail-eopbgr750135.outbound.protection.outlook.com [40.107.75.135]) by sourceware.org (Postfix) with ESMTPS id 00F44385702F for ; Mon, 30 Nov 2020 23:19:10 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 00F44385702F ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=knxHlkpqns2RJ+r204dmslViD2V7IFK0Ak9iRJM+78tx0DRw1EPcjiokk/HJUz3s688W5T+nOQrzZNz93kDFAJtIwI2kK7JtvFWm9VQP+epinF6DLKCCSJLTRv53n2zXrvhIztLcQqwgLY4LmtFJzUUR6q4sd+3CuDnNOlxv5eG3LVkzuElC3VoHQ5RpbT7kkyoNpohSTXKIY1UH/OqMOlTzeaTasBCekTg91GFQakXej5IhyEbdYGKZaINwoePJDZfOrhipK51Ask2nUfLD0tOXGDEtz/34ars8TXMeLfDO4ETK4mhyfph8fkUpeDQMkjPDF7P2O+puTj1jX518qA== 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=UGeRGsLtBiMgl0Nu0s5hMalXrYWgS2MSUUO12ZD26vM=; b=Gajfgi/2SNk052+YLaaGKgF2dlDKBrR1oDsxTx9UcdrjFHUShO6FKzzwbqkfUrIzElfUP8WZlCRBzgH7U4QYbtdkbPhgM8noRfF9Jdr9ar9Z3nLlgz9pbu6W6B9EEisGaBSlA+r9lifltFtNwRogQX3neFNvPG2C6fC7gRyYCyiTUQcBlNMuPzfiPFFvNvW1Jw9voBxuWG8keXiusFdpfCtVS9NECVuT/UNf9QDEKLgfjXK+BquuQKGM8bI77hyMsnSRm7DXpLdkt9wVFApkA21TSd54A85fK65cC7NyCjJjpIQ+qgRZPBjfj8pPcFpMB+e8jX3fxj+HPAux5QGcYQ== 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 MN2PR04MB6176.namprd04.prod.outlook.com (2603:10b6:208:e3::13) by MN2PR04MB5760.namprd04.prod.outlook.com (2603:10b6:208:3e::31) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3611.22; Mon, 30 Nov 2020 23:19:08 +0000 Received: from MN2PR04MB6176.namprd04.prod.outlook.com ([fe80::113e:c874:1207:eca8]) by MN2PR04MB6176.namprd04.prod.outlook.com ([fe80::113e:c874:1207:eca8%6]) with mapi id 15.20.3611.025; Mon, 30 Nov 2020 23:19:08 +0000 Subject: Re: Unix Domain Socket Limitation? To: Norton Allen , cygwin References: <71490665-31b0-f63c-74da-461a053fac21@huarp.harvard.edu> <55ea1649-1979-6238-75ab-69100c22e069@cornell.edu> <4260ad1b-4ab2-fa36-fd0e-7c9644560114@huarp.harvard.edu> <38a82f82-1ef9-768e-7d3e-15f63147e188@cornell.edu> <16165727-f614-1543-70bc-36457ddbf260@cornell.edu> <75d1315b-5a56-a2e5-310d-6ac33a3cf17c@huarp.harvard.edu> From: Ken Brown Message-ID: Date: Mon, 30 Nov 2020 18:19:06 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 In-Reply-To: <75d1315b-5a56-a2e5-310d-6ac33a3cf17c@huarp.harvard.edu> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [68.175.129.7] X-ClientProxiedBy: CH2PR08CA0004.namprd08.prod.outlook.com (2603:10b6:610:5a::14) To MN2PR04MB6176.namprd04.prod.outlook.com (2603:10b6:208:e3::13) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [192.168.0.17] (68.175.129.7) by CH2PR08CA0004.namprd08.prod.outlook.com (2603:10b6:610:5a::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3611.20 via Frontend Transport; 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DIR:OUT; SFP:1102; X-MS-Exchange-AntiSpam-MessageData: =?Windows-1252?Q?s+ow5mGmTCBwrdVxVI3aqCsKnLGqp3SLMNibcYRmeuDfSu5PJ3afCN8X?= =?Windows-1252?Q?YKvofgUE8OoZuK4BhsP23DzgeOEoWDfMe66OFSNTkeeuTapffac9rwMw?= =?Windows-1252?Q?U3bfCMG6O8of18MDLWIvTs06/ZM0AKhk1i5OZvsZFOXZK2grFx+cad6P?= =?Windows-1252?Q?4Y4kwsdun0GiekOzFjs6o9gVBp0h//9D77VPgKPkE8pWdF8n8wjApcz8?= =?Windows-1252?Q?Hu3jzz6JFU9gZCF9jAJ2xkAxNTtYXLJ67KUxabUTmYMDkX3vOQdzYG1f?= =?Windows-1252?Q?F4Ybkpb0W3G4fvHJPcqhq1KJestPW2SLRzRfiSeeuTlcNgQ1dw23YOn+?= =?Windows-1252?Q?t7vJ6lJqNqQVuP42Vm1izB4o8mR1qQxr/r4wmpdolIATBD0ak2+wKA1a?= =?Windows-1252?Q?lQIDcqf5jeWiwXtGWtdszde0ogIPix4BQY93BMx8LqIm7DFIKOznbk0q?= =?Windows-1252?Q?ddIgyHoQVzpJ79YYYCpqVKDPn5cOmjFgjKrRI9uJ83s8w0DVEsXMrurc?= =?Windows-1252?Q?hhwvHlWijGxe0cK1KmtKnRRjzA4Je9qEQoWg9ejAVhoXpv+NOz8hz43z?= =?Windows-1252?Q?+6CNcC/QXc6yndDyCQjL9YAH3+tsL6wzdezETyEZLdAyNvtNt6iVIO1b?= =?Windows-1252?Q?DyOgJ0gZBZ3Fec+apsF1pZjGjuvpkWZM+SKtv6uCpdLWLGNGwpBLHVCo?= =?Windows-1252?Q?1n4vbgPd61k+aQOJJZZODdyOCrgZ4cSfwPR0MuSTFFDEnT+XG+mR9CVZ?= =?Windows-1252?Q?AdvgMSEfTuZ5c/xiJf61uWZZPf05CG11f6lXB4fGFc/wKejWxpD3oVZl?= =?Windows-1252?Q?LvXTL1JPa6U1Sa1X0Ug5mKwvwvjZE8XYFnWBgDZ8blCIk8wmlFhZcywb?= =?Windows-1252?Q?akqrj+n+b9DfAEBh1+dqKaTBVwR17IVHBF0UbmahS4RI9+mGFUJnRG4F?= =?Windows-1252?Q?n3dgu6e6NL91XZY8rN0wa4YssztXgJt2bYXq2uNgBiXdLuR+ptl9jwbd?= =?Windows-1252?Q?d5iJGp1KzQiaW8sBWsT+Uw2eYvII3EXTE2S9xEr/dIE9vTlbQcs5Kqi7?= =?Windows-1252?Q?C8VCyvp8GNQ9Fm4Q?= X-OriginatorOrg: cornell.edu X-MS-Exchange-CrossTenant-Network-Message-Id: 643ebc08-0557-45a9-2492-08d895865642 X-MS-Exchange-CrossTenant-AuthSource: MN2PR04MB6176.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Nov 2020 23:19:07.9935 (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: C7Le1SHOYLws4RwOJRm20/sSTlgfX8xKA0YK7h04brlixP+dklz++kvHlpKtao2YKl1sRy6hr1KblsWgdu8IRg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR04MB5760 X-Spam-Status: No, score=-0.2 required=5.0 tests=BAYES_00, DKIM_INVALID, DKIM_SIGNED, KAM_DMARC_STATUS, MSGID_FROM_MTA_HEADER, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_PASS, SPF_PASS, TXREP autolearn=no 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@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: General Cygwin discussions and problem reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 30 Nov 2020 23:19:11 -0000 On 11/30/2020 1:26 PM, Norton Allen wrote: > On 11/30/2020 1:14 PM, Ken Brown wrote: >> I can reproduce the hang, and it happens if I use the new AF_UNIX code also. >> But what I'm seeing (at least with the new code) isn't exactly what you describe. >> >> When the server's first select call returns, accept succeeds.  The server then >> calls select a second time, and that call doesn't return. I haven't checked >> yet to see what's going on in the client, and I may not get to that for a while. >> > That's good news, and seems to be consistent with my theory that it is some sort > of race condition that might be particularly sensitive to system-specific > timing. I am compiling cygwin1.dll now. Hi Norton, I think there's a mistake in your test program. Shouldn't client_pselect() be waiting for the socket to be write-ready rather than read-ready? Here's a quote from the Posix page for 'connect': If the connection cannot be established immediately and O_NONBLOCK is set for the file descriptor for the socket, connect() shall fail and set errno to [EINPROGRESS], but the connection request shall not be aborted, and the connection shall be established asynchronously.... When the connection has been established asynchronously, pselect(), select(), and poll() shall indicate that the file descriptor for the socket is ready for writing. Ken