From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from omta001.cacentral1.a.cloudfilter.net (omta001.cacentral1.a.cloudfilter.net [3.97.99.32]) by sourceware.org (Postfix) with ESMTPS id A19603858400 for ; Fri, 25 Feb 2022 18:35:27 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org A19603858400 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=SystematicSw.ab.ca Authentication-Results: sourceware.org; spf=none smtp.mailfrom=systematicsw.ab.ca Received: from shw-obgw-4003a.ext.cloudfilter.net ([10.228.9.183]) by cmsmtp with ESMTP id NZbqn0cVL43SgNfR9nI3FS; Fri, 25 Feb 2022 18:35:27 +0000 Received: from [10.0.0.5] ([184.64.124.72]) by cmsmtp with ESMTP id NfR8nZ5nDQV6mNfR8nyVIV; Fri, 25 Feb 2022 18:35:27 +0000 X-Authority-Analysis: v=2.4 cv=PbTsOwtd c=1 sm=1 tr=0 ts=6219216f a=oHm12aVswOWz6TMtn9zYKg==:117 a=oHm12aVswOWz6TMtn9zYKg==:17 a=IkcTkHD0fZMA:10 a=94nOnFI1EgyDtX4ev68A:9 a=QEXdDO2ut3YA:10 Message-ID: <2526762f-71f0-2341-03cc-27f18c0c30f3@SystematicSw.ab.ca> Date: Fri, 25 Feb 2022 11:35:26 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Reply-To: cygwin-patches@cygwin.com Subject: Re: [PATCH 0/2] Provide virtual /dev/fd and /dev/{stdin,stdout,stderr} symlinks Content-Language: en-CA To: cygwin-patches@cygwin.com References: From: Brian Inglis Organization: Systematic Software In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CMAE-Envelope: MS4xfJVmQZRXwj3pyxVv1KeZvETlnVsIMrUjod028l+C1vx/8bwnkd2DOahOV4D9Dn5e8eD8VtVGf17FaqYTIdl8Ntt6ueMj15cWy/7nKhZ8YvzSa4GGuOV9 5HY+ChYtqZ9m51uqUYeAvhDlDdVvrjG2LncK3Og5rsEFQr3gRr2sEVdYRk/shLVSOExCDQDfp3qwQjFxfm5RdqxiwoUfw3ohAWY= X-Spam-Status: No, score=-1163.8 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, KAM_LAZY_DOMAIN_SECURITY, NICE_REPLY_A, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP, T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) 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: Fri, 25 Feb 2022 18:35:29 -0000 On 2022-02-21 06:36, Johannes Schindelin wrote: > These symbolic links are crucial e.g. to support process substitution (Bash's > very nice `<(SOME-COMMAND)` feature). > > For various reasons, it is a bit cumbersome (or impossible) to generate these > symbolic links in all circumstances where Git for Windows wants to use its > close fork of the Cygwin runtime. > > Therefore, let's just handle these symbolic links as implicit, virtual ones. > > If there is appetite for it, I wonder whether we should do something similar > for `/dev/shm` and `/dev/mqueue`? Are these even still used in Cygwin? Looks like that would make sense, as Cygwin appears to create all of those only on first startup (and probably rechecks if they need created every startup) e.g. Cygwin-32 $ ls -Fglot /dev/ | tail -6 lrwxrwxrwx 1 13 Apr 29 2012 fd -> /proc/self/fd/ lrwxrwxrwx 1 15 Apr 29 2012 stderr -> /proc/self/fd/2 lrwxrwxrwx 1 15 Apr 29 2012 stdout -> /proc/self/fd/1| lrwxrwxrwx 1 15 Apr 29 2012 stdin -> /proc/self/fd/0 drwxr-xr-x+ 1 0 Apr 29 2012 mqueue/ drwxr-xr-x+ 1 0 Apr 29 2012 shm/ Cygwin-64 $ ls -Fglot /dev/ | tail -6 drwxrwxrwt+ 1 0 Dec 2 2017 shm/ lrwxrwxrwx 1 13 May 14 2013 fd -> /proc/self/fd/ lrwxrwxrwx 1 15 May 14 2013 stderr -> /proc/self/fd/2 lrwxrwxrwx 1 15 May 14 2013 stdout -> /proc/self/fd/1| lrwxrwxrwx 1 15 May 14 2013 stdin -> /proc/self/fd/0 drwxrwxrwt+ 1 0 May 14 2013 mqueue/ so they would all get 2006-12-01 00:00:00+0000 birth time. [Looks like I ran something using shm in 2017!] -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada This email may be disturbing to some readers as it contains too much technical detail. Reader discretion is advised. [Data in binary units and prefixes, physical quantities in SI.]