• intrigeri's avatar
    Convert a few X session startup programs to `systemd --user' units. · 9fb0136e
    intrigeri authored
    This is merely preparatory work that lays down some foundations.
    For now, we're using two targets:
     * basic.target sets up things that should be done as early as possible, don't
       need access to X, notifications, nor D-Bus ; it is automatically started by
       `systemd --user' when the logind session is created. Note that this happens
       after persistence has been set up, when the GDM autologin is triggered, and
       before /etc/gdm3/Xsession is run:
       - tails-add-GNOME-bookmarks.service
       - tails-create-tor-browser-directories.service
     * desktop.target: we're starting it via xdg/autostart during the GNOME session
       startup. There are a few units wanted by this target so far:
       - tails-configure-keyboard.service
       - tails-virt-notify-user: ideally, this should have something like
         After=notifications-ready.target (and then, most other things that
         wait for GNOME Shell to be ready to handle notifications could do the
         same instead of grep'ing the process list).
       - tails-warn-about-disabled-persistence.service
       - tails-upgrade-frontend.service: the idea is to later use systemd units
         ordering to make it run at a time that increases chances for the system
         having enough free memory; e.g. as soon as possible once the session is
         ready, Tor has bootstrapped, and some other memory-hungry programs we run
         at session startup time have completed.
       - tails-security-check.service: similarly, the idea is that we could get
         rid of the wrapper — that merely waits for Tor to have finished
         bootstrapping — given another systemd unit.
    Most of these units exit early unless they're run by the `amnesia' user.
    Otherwise they break e.g. Tails Greeter startup, and probably worse.
    Also note that the units that may take ages to complete have Type=simple.
    With Type=oneshot, systemd would wait for them to complete before running any
    follow-up units, and before considering the target they're part of has been
    reached. Two of our units can take minutes to complete, so the desktop.target
    startup would fail. Now, using Type=simple has one drawback: it makes it harder
    to order other units relatively to tails-security-check-wrapper's and
    tails-upgrade-frontend-wrapper's completion. This doesn't feel too bothering,
    though: it's more likely that we want to configure these units to start after
    others, than the opposite.
    Also, when the GNOME session is initialized, we import the relevant D-Bus, X11
    and locales variables into systemd --user's environment, so that our units can
    use them. We do that immediately before starting desktop.target.