Messages in this thread | | | Subject | Re: [PATCH] prctl: add PR_{SET,GET}_CHILD_SUBREAPER to allow simple process supervision | From | Valdis.Kletnieks@vt ... | Date | Sat, 07 Jan 2012 11:13:50 -0500 |
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On Sat, 07 Jan 2012 16:56:37 +0100, Kay Sievers said: > Resending this, it got lost last year's September. > > We still need it to properly implement init-like service managers.
> From: Lennart Poettering <lennart@poettering.net> > Subject: prctl: add PR_{SET,GET}_CHILD_SUBREAPER to allow simple process supervision
> Users of this will be the systemd per-user instance, which provides > init-like functionality for the user's login session and D-Bus, which > activates bus services on-demand. Both need init-like capabilities > to be able to properly keep track of the services they start.
> --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -552,6 +552,18 @@ struct signal_struct { > int group_stop_count; > unsigned int flags; /* see SIGNAL_* flags below */ > > + /* > + * PR_SET_CHILD_SUBREAPER marks a process, like a service > + * manager, to re-parent orphan (double-forking) child processes > + * to this process instead of 'init'. The service manager is > + * able to receive SIGCHLD signals and is able to investigate > + * the process until it calls wait(). All children of this > + * process will inherit a flag if they should look for a > + * child_subreaper process at exit. > + */ > + unsigned int is_child_subreaper:1; > + unsigned int has_child_subreaper:1;
Is there someplace we can stick these two fields where they won't expand the signal_struct? Can we stick them in signal_struct->flags instead? Looks like we've only burned 3 bits of that unsigned int. Yes, I know that would complicate the prctl get/set code.
> + /* find the first ancestor marked as child_subreaper */ > + for (reaper = father->real_parent; > + reaper != &init_task; > + reaper = reaper->real_parent) {
I admit being insufficiently caffienated - does this DTRT in a PID namespace? That &init_task looks fishy to me... [unhandled content-type:application/pgp-signature] | |