On Tue, 28 Nov 2017 12:14:29 +0200 Pekka Paalanen <ppaalanen@xxxxxxxxx> wrote: > From: Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxxxx> > > There are many bad and even worse attempts to make Weston run as a > systemd service, and very few good ones. Let's add a good one as an > example in upstream: does not use weston-launch, does not run weston as > root, does not need wrapper scripts, and relies on logind and PAM. > > This example has been composed from a couple of real-world Weston unit > files used in production. It has not been used verbatim, but it has been > briefly tested on one Yocto-based system. > > The service file is not installed by the build. It would likely need > small adjustments for each distribution or system to be deplyed on. > > The session-c1.scope workaround refers to a systemd bug that has been > said to be hard to reproduce, but the details have been lost in time. > > Fixes: https://phabricator.freedesktop.org/T63 > > Cc: martyn.welch@xxxxxxxxxxxxxxx > Cc: fabien.lahoudere@xxxxxxxxxxxxxxx > Cc: matt.hoosier@xxxxxxxxx > Cc: sjoerd.simons@xxxxxxxxxxxxxxx > Signed-off-by: Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxxxx> > > --- > > Hi all, > > I have cross-posted this patch to systemd-devel with the hope that > someone would recall details about the systemd or PAM plugin race that > prompted the session-c1.scope workaround. I belive Martyn spoke about it > in person with Lennart, but as far as Martyn recalls, there is no record > of the issue. Enabling session lingering was mentioned as another > workaround. Hi all, I was recently contacted asking about what happened to this patch. It still hasn't landed in Weston in any form, because this good discussion around November 2017 - January 2018 had suggestions I have not had the time to integrate. I did do a few changes, and the latest is currently tracked at: https://gitlab.freedesktop.org/wayland/weston/merge_requests/39 The lacking bits are those particularly around PAM and the old system specific workaround that is still present. I would be happy if someone wants to take over this, as it is unlikely I can push it forward or test meaningfully myself. Thanks, pq > --- > doc/systemd/README | 45 +++++++++++++++++++++++++++++++ > doc/systemd/weston.service | 66 ++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 111 insertions(+) > create mode 100644 doc/systemd/README > create mode 100644 doc/systemd/weston.service > > diff --git a/doc/systemd/README b/doc/systemd/README > new file mode 100644 > index 00000000..2aa3aa9a > --- /dev/null > +++ b/doc/systemd/README > @@ -0,0 +1,45 @@ > + Systemd integration examples > + > +These examples rely on Weston's logind and systemd support. Weston needs to be > +built with options: --enable-dbus --enable-systemd-login --enable-systemd-notify > + > +Furthermore, Weston needs to be configured to load systemd-notify.so plugin. > +This can be done on the Weston command line: > + > +$ weston --modules=systemd-notify.so > + > +or in weston.ini: > + > +[core] > +modules=systemd-notify.so > + > +The plugin implements the systemd service notification protocol, watchdog > +protocol, and also allows socket activation and configuring listening sockets > +via systemd. > + > + > + weston.service > + > +An example on how to run Weston as a system service. It starts a full user > +session of the named user on the given virtual terminal. > + > +This is useful for running a login manager or for dedicated systems that do not > +have personal user accounts and do not need the user to log in. > + > +You should very least customize the user, but likely also the tty and > +and the weston command line. See 'systemctl edit' command for an easy way to > +do that per-system if you don't edit the service file before installing it. > + > +This approach has an issue that in one system was worked around with the > +"After=session-c1.scope" directive. The details have been forgotten, but > +enabling session lingering was mentioned as another workaround. It might > +perhaps have something to do with multiple system units triggering the setup > +of a user session. It would be much better to start Weston as a systemd user > +service instead to avoid the issue completely. > + > + > +TODO: add an example of socket activation and defining sockets with systemd > + > +TODO: talk about starting Weston as a systemd user service, as that would > +often be more appropriate than as a system service. The user can still be > +automatically logged in. Presumably the auto-login service can allocate the VT. > diff --git a/doc/systemd/weston.service b/doc/systemd/weston.service > new file mode 100644 > index 00000000..80d242a6 > --- /dev/null > +++ b/doc/systemd/weston.service > @@ -0,0 +1,66 @@ > +# This is a system unit for launching Weston with auto-login as the > +# user configured here. > +# > +# Weston must be built with systemd support, and your weston.ini must load > +# the plugin systemd-notify.so. > + > +[Unit] > +Description=Weston, a Wayland compositor, as a system service > +Documentation=man:weston(1) man:weston.ini(5) > +Documentation=http://wayland.freedesktop.org/ > + > +# Make sure we are started after logins are permitted. > +After=systemd-user-sessions.service > + > +# If Plymouth is used, we want to start when it is on its way out. > +After=plymouth-quit-wait.service > + > +# D-Bus is necessary for contacting logind. Logind is required. > +Wants=dbus.socket > +After=dbus.socket > + > +# This scope is created by pam_systemd when logging in as the user. > +# This directive is a workaround to a systemd bug, where the setup of the > +# user session by PAM has some race condition, possibly leading to a failure. > +# See README for more details. > +After=session-c1.scope > + > +# Since we are part of the graphical session, make sure we are started before > +# it is complete. > +Before=graphical.target > + > +# Prevent starting on systems without virtual consoles, Weston requires one > +# for now. > +ConditionPathExists=/dev/tty0 > + > +[Service] > + > +# Requires systemd-notify.so Weston plugin. > +Type=notify > +ExecStart=/usr/bin/weston > + > +# Optional watchdog setup > +TimeoutStartSec=60 > +WatchdogSec=20 > + > +# The user to run Weston as. > +User=westonuser > + > +# Set up a full user session for the user, required by Weston. > +PAMName=login > + > +# A virtual terminal is needed. > +TTYPath=/dev/tty7 > +TTYReset=yes > +TTYVHangup=yes > +TTYVTDisallocate=yes > + > +# Fail to start if not controlling the tty. > +StandardInput=tty-fail > + > +# Log this user with utmp, letting it show up with commands 'w' and 'who'. > +UtmpIdentifier=tty7 > +UtmpMode=user > + > +[install] > +WantedBy=graphical.target
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