Killing the systemd user session on logout

[Bernie Innocenti]

On 12/07/2020 00.14, Bernie Innocenti wrote:
> I'm trying to fix this longstanding bug where there are dangling user 
> processes after the desktop session exists:
> 
>    https://bugs.kde.org/show_bug.cgi?id=359651
> 
> This is reproducible every time on multiple distributions and KDE 
> versions. It also causes subsequent logins to fail or behave 
> surprisingly due to the presence of extraneous dbus services, pulseaudio 
> clients, etc.
> 
> I looked into plasma-workspace/startkde, and there's no hint of it 
> starting "systemd --user" directly. There's this cli tool called 
> "kde-systemd-start-condition" (which appears to be unused), and a few 
> other mentions of logind and systemd, but nothing really relevant.
> 
> Am I looking in the wrong place?

Hmm, well, maybe sddm was the right place to look. I see various places 
where sddm talks about the session with the login1 dbus service:

   https://github.com/sddm/sddm/blob/develop/src/daemon/Display.cpp


Yet, I can't spot the exact place where the session is created. I guess 
the fix for this bug might involve sending a KillSession message after 
startplasma-x11 or startplasma-wayland has exited. Maybe from 
HelperApp::sessionFinished?

-- 
_ // Bernie Innocenti
\X/  https://codewiz.org/