Setting up lightdm for autologin

From: Anton Shepelev <anton.txt_at_gmail.com>
Date: Sat, 29 Jun 2024 22:36:29 UTC
Hello, all.

I need you help in configuring lightdm for autologin on
FreeBSD 14.1.  The handbook does not explain how to do it,
and only mentions that a greeter is not required in case of
autologin:

   <https://docs.freebsd.org/en/books/handbook/desktop/#xfce-start>

I therefore found no better method than following the
ArchLinux instruction about enabling autologin:

   https://wiki.archlinux.org/title/LightDM#Enabling_autologin

with the necessary correction for FreeBSD differences in
tools and paths.  Since it had no effect, i.e. I still was
promtped for login and password by the greeter, I tried to
move pam out of the way and relaxed some tests in /usr/
local/etc/pam.d/lighdm-autologin.so:

   auth     required    pam_env.so
   auth     sufficient  pam_permit.so
   account  sufficient  pam_permit.so

But autologin does not occur, anyway, lightdm.log showing
this warning:

   Failed to get list of logind seats:
     GDbus.Error:org.freedesktop.DBus.Error.ServiceUnknown:
       The name org.freedesktop.login1 was not provided by any .service files

and a failed attempt to autologin:

   pid=1533: Started with service 'lightd-autologin', username '<my_user>'
   pid=1533: Exited with return value 1
   Session:  Failed during authentification

But why?  How can I troubleshoot it?