1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
<?xml version='1.0'?> <!--*-nxml-*-->
<?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
<!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 General Public License as published by
the Free Software Foundation; either version 2 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<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>
<refentrytitle>systemd.device</refentrytitle>
<manvolnum>5</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd.device</refname>
<refpurpose>systemd device configuration files</refpurpose>
</refnamediv>
<refsynopsisdiv>
<para><filename>systemd.device</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>A unit configuration file whose name ends in
<filename>.device</filename> encodes information about
a device unit as exposed in the
sysfs/<citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>
device tree.</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 exist,
since no device-specific options may be
configured.</para>
<para>systemd will automatically create dynamic 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.</para>
<para>Device units are named after the
<filename>/sys</filename> and
<filename>/dev</filename> paths they control. Example:
the device <filename>/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>
</refsect1>
<refsect1>
<title>The udev Database</title>
<para>The settings of device units may either be
configured via unit files, or directly from the udev
database (which is recommended). The following udev
properties are understood by systemd:</para>
<variablelist>
<varlistentry>
<term><varname>SYSTEMD_WANTS=</varname></term>
<listitem><para>Adds dependencies of
type <varname>Wants</varname> from
this unit to all listed units. This
may be used to activate arbitrary
units, when a specific device becomes
available. Note that this and the
other tags are not taken into account
unless the device is tagged with the
"<literal>systemd</literal>" string in
the udev database, because otherwise
the device is not exposed as systemd
unit.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>SYSTEMD_ALIAS=</varname></term>
<listitem><para>Adds an additional
alias name to the device unit. This
must be an absolute path that is
automatically transformed into a unit
name. (See above.)</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>SYSTEMD_READY=</varname></term>
<listitem><para>If set to 0 systemd
will consider this device unplugged
even if it shows up in the udev
tree. If this property is unset or set
to 1 the device will be considered
plugged the moment it shows up in the
udev tree. This property has no
influence on the behaviour when a
device disappears from the udev
tree. This option is useful to support
devices that initially show up in an
uninitialized state in the tree, and for
which a changed event is generated the
moment they are fully set
up.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>ID_MODEL_FROM_DATABASE=</varname></term>
<term><varname>ID_MODEL=</varname></term>
<listitem><para>If set, this property is
used as description string for the
device unit.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
|
