From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from NAM12-DM6-obe.outbound.protection.outlook.com (mail-dm6nam12on2101.outbound.protection.outlook.com [40.107.243.101]) by sourceware.org (Postfix) with ESMTPS id DCE883857C66 for ; Thu, 26 Nov 2020 17:13:14 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org DCE883857C66 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=B8nSqckPXj3qnXt9LGhzqxhotf+/DTbuLTA8jWfTMIRbjeLYaFruiEsGm+LzsjmVSIfmMnzWzav92UTf+y5Z4yHrg9RLZh4n+JYST8GtW7ZMB9W6R/ymljwwZgreYAze+Qk0vMyAYkJpKvKpUS3kWpOz58mZZdADmMHxxvtyak+yMsbo+NGpswXJt35c7USO5OJGqAO8u8GCdliDk3KHFhY7Zo1lVIjuxCGt1b4Jyh52TGfctyD54cOUe2xkVDyIGDb3iegxg9IB2d75A8xIqzGMTUXcqfq1bD9BExGgLaGCoBa8wS7VKwlPQr4qYBbQSeMFultbQC1TN0k+hDb/YQ== 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=fzMrH7Xxx8OopeCciyKt9Sy801BKIpFyn50Bgzswm0s=; b=ZzwBT7Tgn9sR7XlhMWWpQxXO2EEQumX5F/xc+F08UhO+BO/hMRFt6qUtCpmcwgb/3nzIM19AQKj6OGm/yW30CZhJZmvXvj1PSD8LI9LiTrBFMs2DmMfxDqdkNwEvJJLw137gRXaiN+31fJXeS9Z1wxjdd1Iqphn8/MoD8xjdYkLRB10giPmqUTW4jtIXusUwO+yaylbl+mF4qVMUnfKMdYUW1uIUMl5u1JK+gCYAMuwEIrZ90KMsiLu5hkaR89tt2NfObRxKEb9WtKlSQ/eH+vg0WMfhMS/jinbHFggKpLakK+flOeGh2lfh7MdmykQ6Q6nr6mpNm23n1c3DDKPTTg== 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 MN2PR04MB6095.namprd04.prod.outlook.com (2603:10b6:208:d7::32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3589.22; Thu, 26 Nov 2020 17:13:11 +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 15.20.3589.030; Thu, 26 Nov 2020 17:13:10 +0000 Subject: Re: Unix Domain Socket Limitation? To: Norton Allen References: <71490665-31b0-f63c-74da-461a053fac21@huarp.harvard.edu> <55ea1649-1979-6238-75ab-69100c22e069@cornell.edu> <4260ad1b-4ab2-fa36-fd0e-7c9644560114@huarp.harvard.edu> Cc: cygwin From: Ken Brown Message-ID: <38a82f82-1ef9-768e-7d3e-15f63147e188@cornell.edu> Date: Thu, 26 Nov 2020 12:13:08 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 In-Reply-To: <4260ad1b-4ab2-fa36-fd0e-7c9644560114@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: BL0PR05CA0016.namprd05.prod.outlook.com (2603:10b6:208:91::26) 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 BL0PR05CA0016.namprd05.prod.outlook.com (2603:10b6:208:91::26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3632.8 via Frontend Transport; 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DIR:OUT; SFP:1102; X-MS-Exchange-AntiSpam-MessageData: =?Windows-1252?Q?vpJ+iMFN2igXSJAK1bcTuphFqy4HyMWBxDuPeLuLL5aa6BaoJ/mFcpQx?= =?Windows-1252?Q?EVcQFpgGTxgAaGBXoj3EW2bRP0YeREodgXomdmsuXXAo9EgFhJCP9O4G?= =?Windows-1252?Q?gp4JuOm1Qrgr5HRTbULEulyuxzUxjhSdVbuhmMXRwC89QYxrMrnkVCBg?= =?Windows-1252?Q?QTd+kHa41Vyx0Zz4vNRKIxUOV+lTrrOD/t3TCEnFGdFmkclDwewgTHr9?= =?Windows-1252?Q?XNRpjN+lwlvTYkDbhNUMzkHNR3kpzIDuusAx+5HVThv6Pb17G4cWRPF5?= =?Windows-1252?Q?DVzeEgh+hbeCOLYQzQ7btpLBPV1jfzTEYwTeytEV0WpCNohBYIIQDBb0?= =?Windows-1252?Q?+cqxR6U9/lc2WK5DQpECV9eRrX/ZvMfG8k7CC49zSockjYliIohfnc3E?= =?Windows-1252?Q?//9UVE2EQtofNkpAPGKt+N4Ke+1+HJ30OLZxEG5SnDbmvgb5CglXqYMK?= =?Windows-1252?Q?LiCH8JjGTtatyO6VYE1ao6qmwH3csqFmNRLTLieU5xEE8tJr7t/ewGOl?= =?Windows-1252?Q?vQVe5vwaia8wfUUShlOb2bKc0CqvuTAVlqWAnYCgz9vZa9uR4dXbiQwX?= =?Windows-1252?Q?3OcdkH3eUIpQ3V8pahi1i8YCsy7Nrelii2NnnuW6wzZlGPnwsNJiF2NG?= =?Windows-1252?Q?RYQXeE7HCrv0+E/fVS8yCXMd2of6f9oL/xCJhMmaY86JrZfln9HJbgVQ?= =?Windows-1252?Q?Ya7MMydlwwfqKOEb8Q+LSVBujX608Tl8gB56WXtQI5CKWr6KO3sZWI9X?= =?Windows-1252?Q?VEoNn05zWS8GMp835CxPo+EEi3L/lKnbaHUKlegcVNeZXXXu28dYkpMt?= =?Windows-1252?Q?ZcfmmXXzUwiccYQ6VN1Z0y4PXX0pjoFKDgsXKAJ6WRO3epzLaSG6p7/5?= =?Windows-1252?Q?8HmWHD7zePN2E+izqNjZbKQskgimFQ/N3SqGBWyMhB7phq8dm7ya5Vyd?= =?Windows-1252?Q?bOq+qH9PWdnugwd3fLSARbZzYEMD0Ty7zwNwMjqOAlHm3WlIXh5uw5OK?= =?Windows-1252?Q?hJZR2wzW0AEaDjn4JIyXNHps2IOhGLCPf70RE6V/ewD/eV/p4Y6vV3WJ?= =?Windows-1252?Q?RzrRFFjyEwC8/ezk?= X-OriginatorOrg: cornell.edu X-MS-Exchange-CrossTenant-Network-Message-Id: 8d37f130-c56d-4c0d-aa57-08d8922e8c85 X-MS-Exchange-CrossTenant-AuthSource: MN2PR04MB6176.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Nov 2020 17:13:09.8625 (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: ml5FrNTCYoZPlodiwTrwWnd9Ro4ZSJbQxGe46b+5PV7MTkPdmL0cCGjwLdClSnZ3CE8T11JIvy/0G/mBpUJhhg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR04MB6095 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: Thu, 26 Nov 2020 17:13:16 -0000 [Adding the Cygwin list back to the Cc.] On 11/26/2020 11:27 AM, Norton Allen wrote: > On 11/25/2020 5:27 PM, Ken Brown via Cygwin wrote: >> On 11/25/2020 4:47 PM, Norton Allen wrote: >>> In my recent tests, it appears as though it is not possible to successfully >>> connect via two Unix Domain sockets from one client application to one server >>> application. >>> >>> Specifically, if I create a server which listens on a Unix Domain socket and >>> a client, which attempts to connect() twice, both seem to lock up. This is >>> not the behavior under Linux. >>> >>> I will be happy to work up a minimal example if it is helpful in tracking >>> this down. I wanted to start by asking whether this is a known limitation >>> and/or if there is something about the Cygwin implementation that makes this >>> sort of thing very difficult. >> >> A minimal example would be extremely helpful. >> >> Corinna can answer questions about limitations in the current implementation. >> But there is a new implementation under development. It's in the topic/af_unix >> branch of the Cygwin git repository if you're interested in looking at it. >> >> Corinna began working on this a couple years ago, and I've recently been >> trying to finish it.  I've made quite a bit of progress, but there's still >> more to do and undoubtedly many bugs. So any test cases you have would be very >> useful. > > Thanks Ken, > > As it happens, attempting to produce a minimal example suggests my problem may > be somewhere else. I think I've worked in most of the features of my application > one by one but have not yet revealed a failure. OK. But if you ever do have occasion to write small test programs involving AF_UNIX sockets, please send them on. The new AF_UNIX code needs as much testing as it can get. Ken