Re: FEATURE REQUEST : shell option to automatically terminate child processes on parent death

[Corto Beau]

The PDEATHSIG flag is indeed cleared for the child of a fork, but 
preserved across calls to execve.

If there was a way to avoid this and propagate the flag across all 
descendants, I think it would mess up processes that expect their 
children to outlive them.

The rationale for this feature proposal is to be able to avoid leaving 
orphan processes behind ; how said processes manage their own children 
is up to them.

There's another reason the shell option is not a good idea though ; it 
tells Bash to set the PDEATHSIG flag on all direct children, but we 
might want to set the flag only for some specific children. Hence the 
"run_with_pdeathsig" builtin that sets it only for the child created to 
execute the command.

If target-specific features are an issue, I won't push that proposal any 
further.

On 12/11/2023 06:36, Oğuz wrote:
> On Saturday, November 11, 2023, Corto Beau <corto.beau@laposte.net> wrote:
>
>     Do you mean something like a "fork_noreparent" builtin that would
>     call make_child and set PDEATHSIG afterwards, or a "noreparent"
>     builtin that the child would have to call ?
>
> I don't have a preference for either. I oppose it being a shell option 
> because first, it's a single function call that works on only one 
> target platform; and second, its effect doesn't seem to stick. If I'm 
> not missing anything, if I enable the proposed noreparent option in a 
> shell and run a command, and that command forks, its children won't 
> receive the death signal when the shell dies. It doesn't make any sense.
>
> Unless there is a way to make it stick and affect all descendants of 
> the shell process, I don't think this would be very useful as a 
> loadable builtin either.
>
>
> --
> Oğuz