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Processed in 2.145329 secs); 01 Jul 2019 10:09:37 -0000 X-Envelope-From: p.stephenson@samsung.com X-Qmail-Scanner-Mime-Attachments: | X-Qmail-Scanner-Zip-Files: | Received-SPF: pass (ns1.primenet.com.au: SPF record at _spf.samsung.com designates 210.118.77.12 as permitted sender) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout2.w1.samsung.com 20190701100856euoutp028b559d94cec28a5489a47b7a904d7a8d~tQKgHYL9F0760907609euoutp02N DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1561975736; bh=IjySdoELktDHbQmzNdE/Pth6jv5RLpfGHnskR2ZGCmE=; h=Subject:From:To:Date:In-Reply-To:References:From; b=C/rsp1rs95solnyUs+rKwtuKVx0uiwU34szB6DP7fmD2Ev2JUj75PhnltH5HR5Re6 a9VoyaflVMfd/32uIf800iKqzhJUM5320DbTGFhgPUQUKvVoK7SSNhNJXbXsjIuqv3 6HrhUTGzmmEW8ZucJ+OXrsWRdjA+3hkOzDvXZkyk= X-AuditID: cbfec7f2-f2dff700000010ca-66-5d19dbb7e779 Message-ID: <1561975733.6006.2.camel@samsung.com> Subject: Re: <(...), >(...) and fds above 9 From: Peter Stephenson To: Date: Mon, 1 Jul 2019 11:08:53 +0100 In-Reply-To: <20190701100001.hbegs7zyu2auckhf@chaz.gmail.com> X-Mailer: Evolution 3.18.5.2-0ubuntu3.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrAIsWRmVeSWpSXmKPExsWy7djP87rbb0vGGqzdpGJxsPkhkwOjx6qD H5gCGKO4bFJSczLLUov07RK4MqY/Ps9e0MtbsfDvS7YGxmNcXYycHBICJhIzPjWzdzFycQgJ rGCUONDQwwLh9DFJzFnzmA3C6WWS2L3mHitMy9fJB6BaljNKPHw+ixWuasmFU8wQzmlGiWdb OqGc84wSCztPMYL08woYSuz8uRdslrCAtsTta8vA4mxA8ambZoPZIgKSEteaT4PZLAIqEpem 7mEHsTkFbCWe/Z0LdYeGxIabx5ggZgpKnJz5hAXEZhaQl2jeOhtssYTAfTaJrsuNzBANLhIn +g5D2cISr45vYYewZST+75zPBNHQziixZtJrdginh1Fi09E7jBBV1hJ9ty8C2RxAKzQl1u/S hwg7SmxvOcYMEpYQ4JO48VYQ4gg+iUnbpkOFeSU62oQgqtUkdjRtZYQIy0g8XaMwgVFpFpIP ZiH5YBbCqgWMzKsYxVNLi3PTU4sN81LL9YoTc4tL89L1kvNzNzEC08Hpf8c/7WD8einpEKMA B6MSD2/DHYlYIdbEsuLK3EOMEhzMSiK8+1dIxgrxpiRWVqUW5ccXleakFh9ilOZgURLnrWZ4 EC0kkJ5YkpqdmlqQWgSTZeLglGpg3C9vK14bkM7FlscsGLFsjbVD5ZplP3c8Y7B+1hSq6PdO N3rp/j26Rl2V1VmN/87Jld/aHL3n6KwHMgn8a98zPv3DZ6WtnVvb1yMZ6+8RclHzzq2l61ks LmTcMtpnU/rtbNC2v6vuv0h6U/7wRXl22e9YK13eONF9DLrtU2XfHOHqr2G68LJViaU4I9FQ i7moOBEAtZIdnAMDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmpmkeLIzCtJLcpLzFFi42I5/e/4Pd1ttyVjDWZ0GlocbH7I5MDoserg B6YAxig9m6L80pJUhYz84hJbpWhDCyM9Q0sLPSMTSz1DY/NYKyNTJX07m5TUnMyy1CJ9uwS9 jOmPz7MX9PJWLPz7kq2B8RhXFyMnh4SAicTXyQfYuxi5OIQEljJKPNzzig0iISPx6cpHdghb WOLPtS42iKJuJonrrZ2sEM5pRokZF9ZDtZ9nlJi1YT8zSAuvgKHEzp97WUFsYQFtidvXljGC 2GxA8ambZoPZIgKSEteaT4PZLAIqEpem7gFbxylgK/Hs71yoDRMZJR58OAh2E7OApkTr9t9Q N2lIbLh5jAlimaDEyZlPWCBq5CWat85mnsAoNAtJyywkZbOQlC1gZF7FKJJaWpybnltspFec mFtcmpeul5yfu4kRGAHbjv3csoOx613wIUYBDkYlHl6NWxKxQqyJZcWVuYcYJTiYlUR496+Q jBXiTUmsrEotyo8vKs1JLT7EaAr00URmKdHkfGB05pXEG5oamltYGpobmxubWSiJ83YIHIwR EkhPLEnNTk0tSC2C6WPi4JRqYFwjcLu+r9/u8Ov0BW6W/Kvuqm7Z4j77YcStPd7ycYptPxQF e7aeeHbSf+LuvMS226qF9Y+zlRYzuvbUHHihsMFLJ/D5E+bod1ItYgVKBivCphT80lrvb/Dj lG3ygi6tZ9+0SrJmLC9avNjAyO/UF90nyzIie/72Z1mG73x/UHGOzgHn8E4bSSWW4oxEQy3m ouJEAGQXiIiWAgAA X-CMS-MailID: 20190701100855eucas1p269520d36f2c12cba97fa76549e4b70f4 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20190701100058epcas2p25e5f8dbd14d048fe2be1d831f3cf60ab X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20190701100058epcas2p25e5f8dbd14d048fe2be1d831f3cf60ab References: <20190701100001.hbegs7zyu2auckhf@chaz.gmail.com> On Mon, 2019-07-01 at 11:00 +0100, Stephane Chazelas wrote: > /tmp$ zsh -c 'exec {fd}< a; zmodload zsh/system; sysopen -u fd2 /dev/fd/$fd; echo $fd $fd2; exec 7< a; ls -l /proc/self/fd; cat <(ls -l /proc/self/fd)' > 12 13 > total 0 > lrwx------ 1 stephane stephane 64 Jul  1 10:52 0 -> /dev/pts/15 > lrwx------ 1 stephane stephane 64 Jul  1 10:52 1 -> /dev/pts/15 > lr-x------ 1 stephane stephane 64 Jul  1 10:52 12 -> /tmp/a > lr-x------ 1 stephane stephane 64 Jul  1 10:52 13 -> /tmp/a > lrwx------ 1 stephane stephane 64 Jul  1 10:52 2 -> /dev/pts/15 > lr-x------ 1 stephane stephane 64 Jul  1 10:52 3 -> /proc/464/fd > lr-x------ 1 stephane stephane 64 Jul  1 10:52 7 -> /tmp/a > total 0 > lrwx------ 1 stephane stephane 64 Jul  1 10:52 0 -> /dev/null > l-wx------ 1 stephane stephane 64 Jul  1 10:52 1 -> pipe:[2044936] > lrwx------ 1 stephane stephane 64 Jul  1 10:52 2 -> /dev/pts/15 > lr-x------ 1 stephane stephane 64 Jul  1 10:52 3 -> /proc/465/fd > lr-x------ 1 stephane stephane 64 Jul  1 10:52 7 -> /tmp/a > > It seems fds above 9 are closed in those forms of process substitutions.  > > It doesn't happen for the =(...) form of process substitution. > > Is that intentional? I'd be surprised if there was any deliberate intention to make these different, but there may be some detail I can't think of. In general closing file descriptors from 10 up that don't have a good reason to be open is handled by a call to closem() when forking.  There may be a difference in the arguments used here, and "a good reason to be open" is a matter of opinion and documentation rather than logical rigour. pws