From: Bart Schaefer <email@example.com>
To: Jun T <firstname.lastname@example.org>
Cc: Zsh hackers list <email@example.com>
Subject: Re: zargs with -P intermittently failing in zsh 5.9 and macOS
Date: Fri, 27 May 2022 09:10:29 -0700 [thread overview]
Message-ID: <CAH+w=7apQ0aN-xUsyAftJZORJ0iRkpO4Q5ZoOOrMcdeJGH_3Qw@mail.gmail.com> (raw)
On Thu, May 26, 2022 at 10:30 PM Jun T <firstname.lastname@example.org> wrote:
> When wait_for_processes() is called (in signal handler?), wait3(&state)
> _sometimes_ returns with WIFCONTINUED(status) set to true.
> Then wait_for_processes() calls addbgstatus(pid, val) with
> Later the process exits normally, and addbgstatus(pid, 0) is called.
> This means bgstatus_list has two entries for the pid.
> When 'wait pid' calls getbgstatus(pid), it finds the entry with status=19
> and returns it.
Even if it's correct to have two entries, it's wrong to return the
least recent one.
> A simple fix would be, at line 584 of signals.c,
> (A) call addbgstatus() only if WIFCONTINUED() is not true.
I think that's insufficient ... we should be recording the most recent
state, per your question about WIFSTOPPED.
> So I guess we need to call addbgstatus() only if the process has actually
> exited (or killed). If this is the case, better solution would be
> (B) call addbgstatus() only if WIFEXITED() or WIFSIGNALED() is true.
> This it the patch below.
Does that really work? I would expect WIFSIGNALED to be true when
each of WIFSTOPPED and WIFCONTINUED is also true, so it wouldn't
change anything? (There isn't any way to stop/continue without using
a signal that I can think of.)
> Or, if we want to call addbgstatus() unconditionally,
> (C) modify addbgstatus() so that if there is already an entry for
> the pid then update it instead of adding a new entry.
I think either that, or
(D) Make sure getbgstatus() always returns the most recent entry.
But ... there isn't any way for a user / script to examine more than
one job status per PID, so unless we're using it internally somewhere
(?) I would think (C) is best.
next prev parent reply other threads:[~2022-05-27 16:11 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-24 16:09 Eric Nielsen
2022-05-24 17:32 ` Bart Schaefer
2022-05-24 20:21 ` Eric Nielsen
2022-05-24 20:35 ` Bart Schaefer
2022-05-26 8:57 ` Jun T
2022-05-26 11:21 ` Jun. T
2022-05-27 3:39 ` Bart Schaefer
2022-05-27 4:18 ` Lawrence Velázquez
2022-05-27 5:29 ` Jun T
2022-05-27 16:10 ` Bart Schaefer [this message]
2022-05-27 17:25 ` Jun. T
2022-05-29 3:30 ` Bart Schaefer
2022-05-29 14:47 ` Jun. T
2022-05-29 20:07 ` Bart Schaefer
2022-05-30 11:16 ` Jun T
2022-06-07 6:51 ` Jun T
2022-06-09 2:56 ` Bart Schaefer
2022-06-12 16:43 ` Eric Nielsen
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