We don't have plural in the name of any other -util files and this
inconsistency trips me up every time I try to type this file name
from memory. "formats-util" is even hard to pronounce.
It's possible that sd_bus_creds_get_tty() fails and thus
scheduled_shutdown_tty is NULL in method_schedule_shutdown().
Fix logind_wall_tty_filter() to get along with that, by showing the message on
all TTYs, instead of crashing in strcmp().
https://launchpad.net/bugs/1553040
The files are named too generically, so that they might conflict with
the upstream project headers. Hence, let's add a "-util" suffix, to
clarify that this are just our utility headers and not any official
upstream headers.
So far we had two pretty much identical calls in user-util.[ch]:
lookup_uid() and uid_to_name(). Get rid of the former, in favour of the
latter, and while we are at it, rewrite it, to use getpwuid_r()
correctly, inside an allocation loop, as POSIX intended.
Add a timer to print UTMP wall messages so that it repeatedly informs users
about a scheduled shutdown:
* every 1 minute with less than 10 minutes to go
* every 15 minutes with less than 60 minutes to go
* every 30 minutes with less than 180 minutes (3 hours) to go
* every 60 minutes if more than that to go
This functionality only active if the .EnableWallMessages DBus property
is set to true. Also, a custom string can be added to the wall message,
set through the WallMessagePrefix property.
