<?xml version='1.0'?> <!--*-nxml-*-->
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
- "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
-
-<!--
- This file is part of systemd.
-
- Copyright 2010 Lennart Poettering
-
- 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.
-
- systemd is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
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- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
--->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
+ "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
+<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="systemd.device">
<refentryinfo>
<title>systemd.device</title>
<productname>systemd</productname>
-
- <authorgroup>
- <author>
- <contrib>Developer</contrib>
- <firstname>Lennart</firstname>
- <surname>Poettering</surname>
- <email>lennart@poettering.net</email>
- </author>
- </authorgroup>
</refentryinfo>
<refmeta>
<refsect1>
<title>Description</title>
- <para>A unit configuration file whose name ends in
- <literal>.device</literal> encodes information about a device unit
- as exposed in the
- sysfs/<citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- device tree.</para>
+ <para>A unit configuration file whose name ends in <literal>.device</literal> encodes information about a
+ device unit as exposed in the
+ sysfs/<citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry> device
+ tree. This may be used to define dependencies between devices and other units.</para>
<para>This unit type has no specific options. See
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for the common options of all unit configuration files. The common
configuration items are configured in the generic
- <literal>[Unit]</literal> and <literal>[Install]</literal>
- sections. A separate <literal>[Device]</literal> section does not
+ [Unit] and [Install]
+ sections. A separate [Device] section does not
exist, since no device-specific options may be configured.</para>
- <para>systemd will dynamically create device units for all kernel
- devices that are marked with the "systemd" udev tag (by default
- all block and network devices, and a few others). This may be used
- to define dependencies between devices and other units. To tag a
- udev device, use <literal>TAG+="systemd"</literal> in the udev
- rules file, see
- <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- for details.</para>
-
- <para>Device units are named after the <filename>/sys</filename>
- and <filename>/dev</filename> paths they control. Example: the
- device <filename noindex='true'>/dev/sda5</filename> is exposed in
+ <para>systemd will dynamically create device units for all kernel devices that are marked with the
+ <literal>systemd</literal> udev tag (by default all block and network devices, and a few others). Note
+ that <emphasis>if <filename>systemd-udevd.service</filename> is not running, no device units will be
+ available (for example in a typical container)</emphasis>.</para>
+
+ <para>Device units are named after the <filename>/sys/</filename>
+ and <filename>/dev/</filename> paths they control. Example: the
+ device <filename index="false">/dev/sda5</filename> is exposed in
systemd as <filename>dev-sda5.device</filename>. For details about
the escaping logic used to convert a file system path to a unit
name see
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+ <para>To tag a udev device, use <literal>TAG+="systemd"</literal> in the udev rules file, see
+ <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details.
+ </para>
+
<para>Device units will be reloaded by systemd whenever the
corresponding device generates a <literal>changed</literal> event.
Other units can use <varname>ReloadPropagatedFrom=</varname> to react
- to that event</para>
-
+ to that event.</para>
</refsect1>
<refsect1>
- <title>Implicit Dependencies</title>
-
- <para>Many unit types automatically acquire dependencies on device
- units of devices they require. For example,
- <filename>.socket</filename> unit acquire dependencies on the
- device units of the network interface specified in
- <varname>BindToDevice=</varname>. Similar, swap and mount units
- acquire dependencies on the units encapsulating their backing
- block devices.</para>
- </refsect1>
+ <title>Automatic Dependencies</title>
- <refsect1>
- <title>Default Dependencies</title>
+ <refsect2>
+ <title>Implicit Dependencies</title>
+
+ <para>Many unit types automatically acquire dependencies on device
+ units of devices they require. For example,
+ <filename>.socket</filename> unit acquire dependencies on the
+ device units of the network interface specified in
+ <varname>BindToDevice=</varname>. Similar, swap and mount units
+ acquire dependencies on the units encapsulating their backing
+ block devices.</para>
+ </refsect2>
- <para>There are no default dependencies for device units.</para>
+ <refsect2>
+ <title>Default Dependencies</title>
+
+ <para>There are no default dependencies for device units.</para>
+ </refsect2>
</refsect1>
<refsect1>
</varlistentry>
</variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Options</title>
+ <para>Device unit files may include [Unit] and [Install] sections, which are described in
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. No
+ options specific to this file type are supported.</para>
</refsect1>
<refsect1>
<title>See Also</title>
- <para>
- <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- </para>
+ <para><simplelist type="inline">
+ <member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
+ <member><citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
+ </simplelist></para>
</refsect1>
</refentry>
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