bug#37191: Cannot login after graphical install

[Jussi Kuokkanen]

> Hi Jussi,
>
> Jussi Kuokkanen via Bug reports for GNU Guix address@hidden skribis:
>
> > I'm getting a "Cannot make/remove an entry for the specified session" after 
> > logging into the installed system, which returns me to the login prompt. 
> > The cause seems to be shepherd failing to start dbus, which PAM depends on. 
> > System config file and logs as attachments.
>
> [...]
>
> > Aug 26 15:14:04 localhost login[203]: pam_elogind(login:session): Failed to 
> > connect to system bus: No such file or directory
> > Aug 26 15:14:04 localhost login[203]: pam_unix(login:session): session 
> > opened for user jussi by LOGIN(uid=0)
> > Aug 26 15:14:04 localhost login[203]: Cannot make/remove an entry for the 
> > specified session
>
> It seems that there’s at least one serious problem, which is
> /var/run/dbus/system_bus_socket is unavailable, for some reason.
>
> Did the ‘dbus-system’ shepherd service start correctly, or did you get
> messages suggesting otherwise?
>
> Thanks,
> Ludo’.

It failed to start as can be seen from the 'debug' logfile:
> Aug 26 01:27:27 localhost shepherd[1]: Service dbus-system could not be 
> started.