Re: [gentoo-user] Consolekit and elogind switch questions

[Mick]

On Monday, 28 October 2019 08:25:06 GMT Neil Bothwick wrote:
> On Mon, 28 Oct 2019 02:46:45 -0500, Dale wrote:
> > Thanks much for the info.  Maybe the switch will go well for me too.
>
> If it works for you it will be good news for the rest of us ;-)

If hald's list of devices has anything to do with it, Dale is bound to nail it 
on the first (re)boot!  :-)

The consolekit framework is responsible switching between users on a system.  
As I understand it, when you go to 'Plasma/Leave/Switch User' menu option, 
console kit daemon is responsible for:

1. Looking at PAM and any processes you own as a user in a login session.
2. Checking which seat (local or remote) you are logged in as and associating 
the hardware you are using with it (e.g. keyboard, mouse, monitor, etc.).
3. Connecting to the d-bus system bus to manage the local login session and 
pass control of hardware devices to the new user.
4. When the new user enters their credentials at the Display Manager, check 
with PAM what processes the new user is authorised to access/use in their 
login session.

I should have the above mostly correct.  You may ask if any of this control 
framework complexity is *necessary* for a single user called Dale, who won't 
allow anyone else to take his 'seat' at the PC without a fight.  The answer is 
probably no, and this is why simpler desktop environments like *box, 
Enlightenment, etc. do not offer the facility to switch users and therefore do 
not ultimately need consolekit.

There are no screenshots of consolekit/elogind because AFAIK neither offer a 
GUI application.  However, when you run 'ck-list-sessions' in a terminal 
you'll see your local session, as well as any other login sessions you may be 
running at the time, e.g. /dev/tt1, remote logins over ssh and which of these 
are active at the time.

Since consolekit is no longer under development and systemd appears to have 
taken over most of the Linux distros, elogind is the current service which can 
run as stand alone on openrc (just as udev of systemd does).

When elogind is running you can use 'loginctl list-sessions' in a terminal to 
see who's running a session.  The man page gives more options.

You don't *have* to add elogind as a boot service, because any applications 
which need it will launch it themselves.  However, don't be surprised if some 
desktop functions are not working as expected.  For example, the SDDM Display 
Manager's shutdown/reboot buttons may not be displayed and even if they are 
displayed they'll do nothing when you click on them after a reboot.  If after 
a reboot you login/out into your Plasma desktop, then elogind will be running 
and the SDDM buttons should function again normally.

I have converted a number of systems to elogind.  It should be as easy as 
setting in your make.conf:

USE="elogind -consolekit"

grep consolekit -r /etc/portage

to find and remove/replace any USE flags still asking for consolekit to be 
emerged.  Then,

emerge --depclean -v -a consolekit

emerge -uaNDv @world

emerge @preserved-rebuild -v -a

rc-update del consolekit
rc-update add elogind boot

reboot

From memory that's all there is to it.
-- 
Regards,

Mick