From: Cyrill Gorcunov <gorcunov@gmail.com> To: Konstantin Osipov <kostja.osipov@gmail.com> Cc: tml <tarantool-patches@dev.tarantool.org> Subject: Re: [Tarantool-patches] [PATCH 1/5] popen: Introduce a backend engine Date: Sat, 30 Nov 2019 10:36:28 +0300 [thread overview] Message-ID: <20191130073628.GP19879@uranus> (raw) In-Reply-To: <20191130041405.GB31199@atlas> On Sat, Nov 30, 2019 at 07:14:05AM +0300, Konstantin Osipov wrote: > * Cyrill Gorcunov <gorcunov@gmail.com> [19/11/30 07:03]: > > Once we sart using non-blocking IO the read() could return -EAGAIN. > > I think I need to find out how python is handling this situation, > > is their read is blocking or not. > > Take a look at how coio works. It adds the descriptor to the event > loop and yields the current fiber. I will, thanks! You know there is another problem with nonblocking descriptors: consider a case where user runs a script like in my test "input=''; read -n 5 input; echo $input". If you run it inside a regular terminal the script will wait for input to apprear first, but if we provide nonblocking pipe the "read" will exit with -EAGAIN and script fail. Actually my first implementations have been creating pipes with O_NONBLOCK and since such test case start to fail I dropped O_NONBLOCK then. > > The eio reaps children itself, ie calls for wait. Thus imagine a situation, > > we start killing the process like > > > > popen_kill(handle) > > ... > > kill(handle->pid) > > ... > > > > but before we reach kill() this process exited by self or killed > > by a user on the node. The signal handler sets pid = -1 and we > > call kill(-1). Which is wrong of course. > > Can't you check the pid > 0 before you send the signal? This won't work, a signal can interrupt us in any moment and set the pid to -1 between if() and kill().
next prev parent reply other threads:[~2019-11-30 7:36 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-11-28 20:45 [Tarantool-patches] [PATCH 0/5] popen: Add ability to run external process Cyrill Gorcunov 2019-11-28 20:45 ` [Tarantool-patches] [PATCH 1/5] popen: Introduce a backend engine Cyrill Gorcunov 2019-11-29 5:52 ` Konstantin Osipov 2019-11-29 9:57 ` Cyrill Gorcunov 2019-11-29 5:59 ` Konstantin Osipov 2019-11-29 9:40 ` Cyrill Gorcunov 2019-11-29 11:19 ` Konstantin Osipov 2019-11-29 11:36 ` Cyrill Gorcunov 2019-11-29 14:50 ` Konstantin Osipov 2019-11-29 15:14 ` Cyrill Gorcunov 2019-11-29 15:17 ` Cyrill Gorcunov 2019-11-29 18:31 ` Konstantin Osipov 2019-11-29 19:17 ` Cyrill Gorcunov 2019-11-29 22:36 ` Cyrill Gorcunov 2019-11-30 4:21 ` Konstantin Osipov 2019-11-30 7:48 ` Cyrill Gorcunov 2019-11-30 4:14 ` Konstantin Osipov 2019-11-30 7:36 ` Cyrill Gorcunov [this message] 2019-11-30 10:04 ` Konstantin Osipov 2019-11-30 10:47 ` Cyrill Gorcunov 2019-11-30 10:54 ` Cyrill Gorcunov 2019-11-30 12:16 ` Cyrill Gorcunov 2019-11-30 20:30 ` Konstantin Osipov 2019-11-30 20:36 ` Cyrill Gorcunov 2019-12-13 2:50 ` Alexander Turenko 2019-11-28 20:45 ` [Tarantool-patches] [PATCH 2/5] lua/fio: Add lbox_fio_push_error as a separate helper Cyrill Gorcunov 2019-11-29 6:02 ` Konstantin Osipov 2019-11-29 9:47 ` Cyrill Gorcunov 2019-11-29 11:22 ` Konstantin Osipov 2019-11-29 11:42 ` Cyrill Gorcunov 2019-11-29 14:51 ` Konstantin Osipov 2019-11-28 20:45 ` [Tarantool-patches] [PATCH 3/5] popen/fio: Merge popen engine into fio internal module Cyrill Gorcunov 2019-11-28 20:45 ` [Tarantool-patches] [PATCH 4/5] popen/fio: Implement lua interface for a popen object Cyrill Gorcunov 2019-11-28 20:45 ` [Tarantool-patches] [PATCH 5/5] test: Add app/popen test Cyrill Gorcunov
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