Always use VT_OPENQRY

[Vogtinator]

There is no other way to reliably grab a VT for use.

+ bonus tty fix.

Draft because not tested yet.

[Vogtinator]

The PR works, but does unfortunately not fix the issue. It's broken at a lower level, VT_OPENQRY lies. Even after systemd claims it started getty@ttyX, VT_OPENQRY still returns X as available!

From journalctl:

Mar 18 16:15:45 localhost.localdomain systemd[1]: Started Getty on tty1.
Mar 18 16:15:45 localhost.localdomain systemd[1]: Started Getty on tty2.
Mar 18 16:15:45 localhost.localdomain systemd[1]: Reached target Login Prompts.
Mar 18 16:15:45 localhost.localdomain systemd[1]: Starting Postfix Mail Transport Agent...
Mar 18 16:15:45 localhost.localdomain systemd[1]: Started Simple Desktop Display Manager.
...
Mar 18 16:15:45 localhost.localdomain sddm[1059]: Doing open /dev/tty0
Mar 18 16:15:45 localhost.localdomain sddm[1059]: Did VT_OPENQRY 2
Mar 18 16:15:45 localhost.localdomain sddm[1059]: Xauthority path: "/run/sddm/xauth_rpUCLS"
Mar 18 16:15:45 localhost.localdomain sddm[1059]: Using VT 2
...
Mar 18 16:15:46 localhost.localdomain sddm[1059]: Doing open /dev/tty0
Mar 18 16:15:46 localhost.localdomain sddm[1059]: Did VT_OPENQRY 1
Mar 18 16:15:46 localhost.localdomain sddm[1059]: Session "/usr/share/wayland-sessions/plasmawayland.desktop" selected, command: "/usr/libexec/plasma-dbus-run-session-if-needed /usr/bin/startplasma-wayland" for VT 1

[Vogtinator]

Even after systemd claims it started getty@ttyX, VT_OPENQRY still returns X as available!

Apparently getty@.service has Type=idle which means it is marked as active before anything actually happened. I don't see a way to fix this.

[Vogtinator]

Even after systemd claims it started getty@ttyX, VT_OPENQRY still returns X as available!

Apparently getty@.service has Type=idle which means it is marked as active before anything actually happened. I don't see a way to fix this.

Reported as systemd/systemd#31909

[ftiede]

Sorry to mention this, but there is a reason I fixed #1650: I want sddm to run on a specific VT. Removing the feature entirely renders SDDM unusable for me.
Essentially this PR means I need to revert it completely in the future.

[Vogtinator]

Sorry to mention this, but there is a reason I fixed #1650: I want sddm to run on a specific VT. Removing the feature entirely renders SDDM unusable for me.

The option to use a specific VT only ever works in the specific case of rootful X with an X desktop inside, everything else needs dynamic allocation.

You can influence dynamic allocation to reserve lower VTs though and get SDDM to use a specific one that way.

[Vogtinator]

I plan to make some changes to this PR anyway (open the tty in the daemon process), which should make it easier to reintroduce SDDM_INITIAL_VT in a way that actually works though.