[systemd-devel] [PATCH] Allow PID 1 systemd --user instances to exit

[Lennart Poettering]

On Thu, 06.11.14 16:59, Vito Caputo (vito.caputo at coreos.com) wrote:

> Because for all intents and purposes it's effectively still a user
> instance, just having its own PID namespace isn't cause --system behaviors
> like disabling systemctl exit for example.

I am pretty sure doing something like this will break at a ton of
other places.

I really wonder if it's worth supporting this, after all a lot of our
code checks getpid() == 1 to see if we are run in system mode. I mean,
once upon a time we had a mode in systemd, where we supported running
--system system as PID != 1. We removed that because it only ever
half-worked, because it confused things, because the usecase was
weak, because nobody really cared and because it bitrotted. Now,
supporting running systemd --user in a PID namespace kinda feels like
the same story, just inverted. Which makes me immediately wonder why
this should be different for this case.

So, what's the real usecase for all of this? Can you elaborate on
that? 

> Preventing exit from PID 1 makes sense when you're going to panic the
> kernel, but doesn't --user imply otherwise?

Well, the --user switch as PID 1 is probably something we should
refuse early on...

Lennart

-- 
Lennart Poettering, Red Hat