In order to prepare things for the single-writer cgroup scheme, let's
make logind use systemd's own primitives for cgroup management.
Every login user now gets his own private slice unit, in which his sessions
live in a scope unit each. Also, add user@$UID.service to the same
slice, and implicitly start it on first login.
While most folks will be using the derivative from user-session-units,
I'm updating this one to reflect some of the fixes and things to note
about user sessions:
- cgroup should be set with "%u" - username instead of %I
- set dbus path with %U explicitly too
- hint to folks that wish to use MEM_CG features in user sessions
- allow unit to be enabled for instances with systemctl enable
We finally got the OK from all contributors with non-trivial commits to
relicense systemd from GPL2+ to LGPL2.1+.
Some udev bits continue to be GPL2+ for now, but we are looking into
relicensing them too, to allow free copy/paste of all code within
systemd.
The bits that used to be MIT continue to be MIT.
The big benefit of the relicensing is that closed source code may now
link against libsystemd-login.so and friends.
