systemd/units/systemd-boot-update.service

#  SPDX-License-Identifier: LGPL-2.1-or-later
#
#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.

[Unit]
Description=Automatic Boot Loader Update
Documentation=man:bootctl(1)
DefaultDependencies=no
Conflicts=shutdown.target
After=local-fs.target
Before=sysinit.target shutdown.target systemd-update-done.service

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=bootctl --no-variables --graceful update

[Install]
WantedBy=sysinit.target
boot: optionally update sd-boot on boot Boot loaders are software like any other, and hence muse be updated in regular intervals. Let's add a simple (optional) service that updates sd-boot automatically from the host if it is found installed but out-of-date in the ESP. Note that traditional distros probably should invoke "bootctl update" directly from the package scripts whenver they update the sd-boot package. This new service is primarily intended for image-based update systems, i.e. where the rootfs or /usr are atomically updated in A/B style and where the current boot loader should be synced into the ESP from the currently booted image every now and then. It can also act as safety net if the packaging scripts in classic systems are't doing the bootctl update stuff themselves. Since updating boot loaders mit be a tiny bit risky (even though we try really hard to make them robust, by fsck'ing the ESP and mounting it only on demand, by doing updates mostly as single file updates and by fsync()ing heavily) this is an optional feature, i.e. subject to "systemctl enable". However, since it's the right thing to do I think, it's enabled by default via the preset logic. Note that the updating logic is implemented gracefully: i.e. it's a NOP if the boot loader is already new enough, or was never installed. 2021-07-02 21:04:10 +08:00			`# SPDX-License-Identifier: LGPL-2.1-or-later`
			`#`
			`# This file is part of systemd.`
			`#`
			`# systemd is free software; you can redistribute it and/or modify it`
			`# under the terms of the GNU Lesser General Public License as published by`
			`# the Free Software Foundation; either version 2.1 of the License, or`
			`# (at your option) any later version.`

			`[Unit]`
			`Description=Automatic Boot Loader Update`
			`Documentation=man:bootctl(1)`
			`DefaultDependencies=no`
			`Conflicts=shutdown.target`
			`After=local-fs.target`
			`Before=sysinit.target shutdown.target systemd-update-done.service`

			`[Service]`
			`Type=oneshot`
			`RemainAfterExit=yes`
			`ExecStart=bootctl --no-variables --graceful update`

			`[Install]`
			`WantedBy=sysinit.target`