On 2/20/20 3:02 AM, Denys Vlasenko wrote:
> On 2/19/20 9:30 PM, Chet Ramey wrote:
>> On 2/19/20 5:29 AM, Denys Vlasenko wrote:
>>> A bug report from Harald van Dijk:
>>>
>>> test2.sh:
>>> trap 'kill $!; exit' TERM
>>> { kill $$; exec sleep 9; } &
>>> wait $!
>>>
>>> The above script ought exit quickly, and not leave a stray
>>> "sleep" child:
>>> (1) if "kill $$" signal is delivered before "wait",
>>> then TERM trap will kill the child, and exit.
>>
>> This strikes me as a shaky assumption, dependent on when the shell receives
>> the SIGTERM and when it runs traps.
>
> The undisputable fact is that after shell forks a child
> to run the "{...} &" subshell, it will receive the SIGTERM signal.
>
> And since it has a trap for it, it should be run.
>
>> (There's nothing in POSIX that says
>> when pending traps are processed. Bash runs them after commands.)
>
> Yes, and here we are "after command", specifically after "{...} &" command.
> Since we got a trapped signal, we must run its trap.
Did you look at the scenario in my message?
Keep in mind that you can't run the trap out of the signal handler.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU c...@case.edu http://tiswww.cwru.edu/~chet/
