Process hierarchy on a DC?

Ralph Böhme slow at samba.org
Sat Apr 29 10:30:57 UTC 2017


On Sat, Apr 29, 2017 at 05:18:19AM -0400, Simo Sorce via samba-technical wrote:
> Sorry for the dumb question, but why are you doing double forks and escaping
> the original process group,

fwiw, this is actually not caused by my code, running in a different process
group (and session) is just the expected result given the arguemts source4
passes to samba_runcmd_send() to start smbd and winbindd. It doesn't pass
--no-process-group so smbd and winbindd put themselves in a new process group by
calling become_daeomon() with no_process_group=false.

> ... and then try to undo all this stuff by sending
> around new process groups to kill ?

The idea is to avoid dealing with SIGCHLD and waitpid in the caller.

> Why not just do a simple straight fork and retain the process group and
> hierarchy ?

Because it's requires coordination with other subsystems that use fork. Eg in
source3 we use CatchChild() to install a SIGCHLD handler what reaps alld
child. This interferes with the current implementation of samba_runcmd_send().

-slow



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