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11a1589223
Files which are installed as-is (any .service and other unit files, .conf files, .policy files, etc), are left as is. My assumption is that SPDX identifiers are not yet that well known, so it's better to retain the extended header to avoid any doubt. I also kept any copyright lines. We can probably remove them, but it'd nice to obtain explicit acks from all involved authors before doing that.
110 lines
4.2 KiB
XML
110 lines
4.2 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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SPDX-License-Identifier: LGPL-2.1+
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This file is part of systemd.
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Copyright 2012 Lennart Poettering
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-->
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<refentry id="systemd-halt.service">
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<refentryinfo>
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<title>systemd-halt.service</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>systemd-halt.service</refentrytitle>
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<manvolnum>8</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>systemd-halt.service</refname>
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<refname>systemd-poweroff.service</refname>
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<refname>systemd-reboot.service</refname>
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<refname>systemd-kexec.service</refname>
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<refname>systemd-shutdown</refname>
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<refpurpose>System shutdown logic</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<para><filename>systemd-halt.service</filename></para>
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<para><filename>systemd-poweroff.service</filename></para>
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<para><filename>systemd-reboot.service</filename></para>
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<para><filename>systemd-kexec.service</filename></para>
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<para><filename>/usr/lib/systemd/systemd-shutdown</filename></para>
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<para><filename>/usr/lib/systemd/system-shutdown/</filename></para>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><filename>systemd-halt.service</filename> is a system
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service that is pulled in by <filename>halt.target</filename> and
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is responsible for the actual system halt. Similarly,
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<filename>systemd-poweroff.service</filename> is pulled in by
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<filename>poweroff.target</filename>,
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<filename>systemd-reboot.service</filename> by
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<filename>reboot.target</filename> and
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<filename>systemd-kexec.service</filename> by
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<filename>kexec.target</filename> to execute the respective
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actions.</para>
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<para>When these services are run, they ensure that PID 1 is
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replaced by the
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<filename>/usr/lib/systemd/systemd-shutdown</filename> tool which
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is then responsible for the actual shutdown. Before shutting down,
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this binary will try to unmount all remaining file systems,
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disable all remaining swap devices, detach all remaining storage
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devices and kill all remaining processes.</para>
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<para>It is necessary to have this code in a separate binary
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because otherwise rebooting after an upgrade might be broken — the
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running PID 1 could still depend on libraries which are not
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available any more, thus keeping the file system busy, which then
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cannot be re-mounted read-only.</para>
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<para>Immediately before executing the actual system
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halt/poweroff/reboot/kexec <filename>systemd-shutdown</filename>
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will run all executables in
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<filename>/usr/lib/systemd/system-shutdown/</filename> and pass
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one arguments to them: either <literal>halt</literal>,
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<literal>poweroff</literal>, <literal>reboot</literal> or
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<literal>kexec</literal>, depending on the chosen action. All
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executables in this directory are executed in parallel, and
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execution of the action is not continued before all executables
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finished.</para>
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<para>Note that <filename>systemd-halt.service</filename> (and the
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related units) should never be executed directly. Instead, trigger
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system shutdown with a command such as <literal>systemctl
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halt</literal> or suchlike.</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para>
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>systemd-suspend.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>bootup</refentrytitle><manvolnum>7</manvolnum></citerefentry>
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</para>
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</refsect1>
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</refentry>
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