Re: wait and SIGSTOP

[Hadrien Lacour <hadrien.lacour@xxxxxxxxxx>]

On Wed, Nov 14, 2018 at 02:07:05AM +0100, Hadrien Lacour wrote:
> On Wed, Nov 14, 2018 at 01:34:10AM +0100, Hadrien Lacour wrote:
> > On Mon, Nov 12, 2018 at 05:08:15PM +0100, Hadrien Lacour wrote:
> > > Hello,
> > >
> > > after reading https://www.mail-archive.com/dash@xxxxxxxxxxxxxxx/msg00683.html,
> > > I still wonder what the correct behaviour is supposed to be. The last message
> > > lets me think that untrapped signals shouldn't interrupt wait. With the script
> > >
> > >     #!/bin/dash
> > >
> > >     sleep 100 &
> > >     echo $!
> > >     wait $!
> > >     echo status: $?
> > >
> > > wait still exits immediatly with status 128 when I kill -STOP the output pid
> > > . The other shells I tested still wait for the job and give me:
> > > * bash: 143
> > > * zsh: 147
> > > * busybox ash: 143
> > >
> > > (this was using dash 0.5.10.2)
> > >
> > >
> > > Sincerly,
> > > Hadrien Lacour
> >
> > After some more testing, I'm even more confused, here's what I get when
> > 1) running kill -STOP then kill -CONT on sleep
> > 2) running kill on sleep
> >
> > +-------------+-------------------------------+------+
> > | shell       | kill -STOP; kill -CONT        | kill |
> > +-------------+-------------------------------+------+
> > | zsh         | 147                           | 143  |
> > +-------------+-------------------------------+------+
> > | bash        | 0                             | 143  |
> > +-------------+-------------------------------+------+
> > | busybox ash | 0                             | 143  |
> > +-------------+-------------------------------+------+
> > | dash        | 128 (SIGSTOP interrupts wait) | 143  |
> > +-------------+-------------------------------+------+
> >
> > After reading `man 1p wait` more carefully, I think that bash and busybox ash
> > have the correct behviour.
>
> Here's a way to test it without touching anything:
>
> > for sh in zsh bash dash "busybox ash"
> do
> $sh test.sh &; sleep 0.5; pid=$(cat sleep.pid); kill -STOP $pid; sleep 0.5; kill -CONT $pid; wait $!
> $sh test.sh &; sleep 0.5; pid=$(cat sleep.pid); kill $pid
> done 2>/dev/null| grep '^status'

Sorry, I'm tired, forgot the new script:

	sleep 5 &
	echo $! >sleep.pid
	wait $!
	echo status: $?