[systemd-devel] [hostnamed] Why the service will automatically exit after 30 seconds

[Michael Chapman]

On Thu, 19 Aug 2021, Michael Chapman wrote:
> On Thu, 19 Aug 2021, Cristian Rodríguez wrote:
> > On Tue, Aug 17, 2021 at 9:35 PM 李成刚 <lichenggang at uniontech.com> wrote:
> > >
> > > How to configure this service so that it will not automatically exit
> > 
> > 
> > So what are you trying to accomplish with this ? why do you need yet
> > another service running when it is totally idle ?
> > 
> > > When the systemd-hostnamed service is started through policykit, the password window will automatically exit, which seems to be a terrible experience
> > 
> > DAFUQ? if polkit is really talking to hostnamed then has to deal with
> > things so they either remaining alive or connect again ...
> 
> It's the other way around. hostnamed uses polkit to authorise requests 
> sent to it over D-Bus.
> 
> If hostnamed is exiting while in the middle of a polkit conversation, then 
> yes I would say that is a bug in hostnamed. It really ought not to do 
> that.

I've looked at this more closely now, and it's a bit more complicated than 
I would have liked.

While hostnamed's own idle timeout can easily be disabled while a 
polkit conversation is in progress, that won't necessarily help anybody 
using hostnamectl. hostnamectl uses sd-bus's default method call timeout, 
which is 25 seconds.

Perhaps this should be increased for method calls that are likely to 
result in using polkit? 25 seconds might be too short for some people to 
enter their password.

Is it possible for sd_bus_call to detect that the recipient of a call has 
dropped off the bus and is never going to return a response? If that were 
possible we could possibly rely on that rather than an explicit timeout. I 
think the answer to this question might be "no" though...