From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by sourceware.org (Postfix) with ESMTPS id 05BBB3858CDA for ; Tue, 9 Apr 2024 16:38:33 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 05BBB3858CDA Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=SystematicSW.ab.ca Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=SystematicSW.ab.ca ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 05BBB3858CDA Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=216.40.44.15 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1712680714; cv=none; b=rLFc9EakzNQ3p8nizS6tWJn9jD+h9G7cazRbqUfcxu55Xd7gWDGvou3wb/r6phVnEkBKSsiuOip4iVs8LqBklVGisa+0V0Fhd2DW/LarjrAR7IwcSg6wBtRRXlRuJxcarrDvOUlvBea8Tnk4Baf9qmtB+4qs8tJvH8fenXRM0ck= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1712680714; c=relaxed/simple; bh=5bZ0FHGO746DwKhsBgLQFnRnsOoShGxTmjQSNrpvPjc=; h=Message-ID:Date:MIME-Version:Subject:To:From; b=JcVD6GxsuvMkgy8OFxp/k+nsLyyl2DHCcNsXci3KtH3R4Ev41tg8gLSw/3k7K/hJlK/rSoDW6APTP9vtl5U8FeVHXh83tp6kMdpf6Dk7Jrq4IdEJzhRHcCrjro8qjz2177l62xjFSlr7DC4mXzCtyJxDTkijc3ade+mU6yby+t0= ARC-Authentication-Results: i=1; server2.sourceware.org Received: from omf15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 6464EC04BF for ; Tue, 9 Apr 2024 16:38:32 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: Brian.Inglis@SystematicSW.ab.ca) by omf15.hostedemail.com (Postfix) with ESMTPA id D8C391A for ; Tue, 9 Apr 2024 16:38:30 +0000 (UTC) Message-ID: <8180fe90-776b-4ba0-9752-09186a08d771@SystematicSW.ab.ca> Date: Tue, 9 Apr 2024 10:38:29 -0600 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Reply-To: cygwin-patches@cygwin.com Subject: Re: /proc//{cwd, root} links to for cygrunsrv, daemons, and shells Content-Language: en-CA To: cygwin-patches@cygwin.com References: <0df79ac3-02ea-4180-8177-375407dee2a1@SystematicSW.ab.ca> From: Brian Inglis Organization: Systematic Software In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Stat-Signature: 67zcz5tcrfa3rhboke5r7oiy63gq33hp X-Rspamd-Server: rspamout07 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,KAM_DMARC_STATUS,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,SPF_HELO_PASS,SPF_PASS,TXREP,UNPARSEABLE_RELAY autolearn=ham autolearn_force=no version=3.4.6 X-Rspamd-Queue-Id: D8C391A X-Session-Marker: 427269616E2E496E676C69734053797374656D6174696353572E61622E6361 X-Session-ID: U2FsdGVkX1/xcdCR8DO/mMeA9AgZz+5mMhkz/71BcI4= X-HE-Tag: 1712680710-655411 X-HE-Meta: U2FsdGVkX1/OWSNaks2sgiylCDkE6a/2eJaNe2pLEUUgbciTiP7rWR4y0wOLwVTSKxbfT6yGpw2q3GKVD/4rgYXjtUvvuuHYajhyKoOHN4tyZWKCcyQvCQA0Xn1JavwxtgMo+UXaQWfRYIi7/mzhYiY7wLNEparekiu9UHsGW3N8MVDhC1r/B6aH9yWXocWBC7pg8R84nr2NLPC630fGplFw4fCI2dBcrckuFYDGZe6ORGi/Ib4u+3FwIRZ6d/fMw9cFoZHv52sGTnHFSvcP1bTe5Bo7Hyk0oNmGP1KjWbDHwVjGOA15p3aLwzH3n0RzuZMex2ZxRKuZqBpsCIfvx/ByXD3779+J X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On 2024-04-09 07:08, Corinna Vinschen wrote: > On Apr 7 13:34, Brian Inglis wrote: >> ISTM anomalous that for cygrunsrv, daemons, cron processes, and shells >> /proc//{cwd,root} have bad symlinks to "", normally a process >> or exe status: >> >> /proc/732/exe -> /usr/bin/cygrunsrv >> /proc/732/root -> >> /proc/732/cwd -> >> | /proc/733/exe -> /usr/sbin/cygserver >> ->/proc/733/root -> >> /proc/733/cwd -> >> /proc/740/exe -> /usr/bin/cygrunsrv >> /proc/740/root -> >> /proc/740/cwd -> >> | /proc/741/exe -> /usr/sbin/syslog-ng >> ->/proc/741/root -> >> /proc/741/cwd -> >> /proc/748/exe -> /usr/bin/cygrunsrv >> /proc/748/root -> >> /proc/748/cwd -> >> | /proc/749/exe -> /usr/sbin/cron >> ->/proc/749/root -> >> /proc/749/cwd -> >> | /proc/2080/exe -> /usr/sbin/cron >> ->/proc/2080/root -> >> /proc/2080/cwd -> >> | /proc/2082/exe -> /usr/bin/bash >> ->/proc/2082/root -> >> /proc/2082/cwd -> >> >> Should we consider changing that to root "/", or nothing, null, or something >> meaningful? > > That's typically a permission problem. On Linux you get something like > > ls: cannot read symbolic link '/proc/1/cwd': Permission denied Thanks Corinna, That now makes sense, as Cygwin ps -a and btop showed the processes, although procps and top did not, and other info is visible, I never thought about permissions as there were links, but I see from elevated admin sh: /proc/732/exe -> /usr/bin/cygrunsrv /proc/732/root -> / /proc/732/cwd -> /proc/cygdrive/c/WINDOWS/system32 | /proc/733/exe -> /usr/sbin/cygserver ->/proc/733/root -> / /proc/733/cwd -> /proc/cygdrive/WINDOWS/system32 /proc/740/exe -> /usr/bin/cygrunsrv /proc/740/root -> / /proc/740/cwd -> /proc/cygdrive/WINDOWS/system32 | /proc/741/exe -> /usr/sbin/syslog-ng ->/proc/741/root -> / /proc/741/cwd -> /proc/cygdrive/WINDOWS/system32 /proc/748/exe -> /usr/bin/cygrunsrv /proc/748/root -> / /proc/748/cwd -> /proc/cygdrive/WINDOWS/system32 | /proc/749/exe -> /usr/sbin/cron ->/proc/749/root -> / /proc/749/cwd -> /var/cron and from normal mintty bash: $ stat -L -c%a\ %A\ %n /proc/732/* 444 -r--r--r-- /proc/732/cmdline 444 -r--r--r-- /proc/732/ctty stat: cannot stat '/proc/732/cwd': No such file or directory 444 -r--r--r-- /proc/732/environ 755 -rwxr-xr-x /proc/732/exe 444 -r--r--r-- /proc/732/exename 555 dr-xr-xr-x /proc/732/fd 444 -r--r--r-- /proc/732/gid 444 -r--r--r-- /proc/732/maps 444 -r--r--r-- /proc/732/mountinfo 444 -r--r--r-- /proc/732/mounts 444 -r--r--r-- /proc/732/pgid 444 -r--r--r-- /proc/732/ppid stat: cannot stat '/proc/732/root': No such file or directory 444 -r--r--r-- /proc/732/sid 444 -r--r--r-- /proc/732/stat 444 -r--r--r-- /proc/732/statm 444 -r--r--r-- /proc/732/status 444 -r--r--r-- /proc/732/uid 444 -r--r--r-- /proc/732/winexename 444 -r--r--r-- /proc/732/winpid $ more /proc/732/* > /dev/null more: cannot open /proc/732/cwd: No such file or directory more: cannot open /proc/732/maps: Permission denied more: cannot open /proc/732/root: No such file or directory more: cannot open /proc/732/stat: Permission denied more: cannot open /proc/732/statm: Permission denied so I think perms on these should be 440 or 550 not 444 or 555, but that may involve a lot of work to decide that for each entry? > But on Cygwin the content of those links require to open the processes' > signal pipe and send/receive a message containing the information. I > didn't look into the code for a while but it seems we don't check why we > couldn't connect to a process to fetch the info. IIRC the current > fhandler_process framework doesn't have a way to communicate that > info. > > If you want to change that, feel free! I will take a look sometime but no promises of any patch(es) ;^> -- Take care. Thanks, Brian Inglis Calgary, Alberta, Canada La perfection est atteinte Perfection is achieved non pas lorsqu'il n'y a plus rien à ajouter not when there is no more to add mais lorsqu'il n'y a plus rien à retirer but when there is no more to cut -- Antoine de Saint-Exupéry