summaryrefslogtreecommitdiff
path: root/man/systemd-udevd.service.xml
blob: 7fce3000f5516179613be6df208ec9c1103791df (plain)
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
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
<?xml version='1.0'?>
<?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">

<refentry id="systemd-udevd.service">
  <refentryinfo>
    <title>systemd-udevd.service</title>
    <productname>systemd</productname>
    <authorgroup>
      <author>
        <contrib>Developer</contrib>
        <firstname>Kay</firstname>
        <surname>Sievers</surname>
        <email>kay@vrfy.org</email>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd-udevd.service</refentrytitle>
    <manvolnum>8</manvolnum>
    <refmiscinfo class="version"></refmiscinfo>
  </refmeta>

  <refnamediv>
    <refname>systemd-udevd.service</refname>
    <refname>systemd-udevd-control.socket</refname>
    <refname>systemd-udevd-kernel.socket</refname>
    <refname>systemd-udevd</refname>
    <refpurpose>Device event managing daemon</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <para><filename>systemd-udevd.service</filename></para>
    <para><filename>systemd-udevd-control.socket</filename></para>
    <para><filename>systemd-udevd-kernel.socket</filename></para>

    <cmdsynopsis>
      <command>/usr/lib/systemd/systemd-udevd</command>
      <arg><option>--daemon</option></arg>
      <arg><option>--debug</option></arg>
      <arg><option>--children-max=</option></arg>
      <arg><option>--exec-delay=</option></arg>
      <arg><option>--resolve-names=early|late|never</option></arg>
      <arg><option>--version</option></arg>
      <arg><option>--help</option></arg>
    </cmdsynopsis>

  </refsynopsisdiv>

  <refsect1><title>Description</title>
    <para><command>systemd-udevd</command> listens to kernel uevents.
      For every event, systemd-udevd executes matching instructions
      specified in udev rules. See <citerefentry>
      <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum>
      </citerefentry>.</para>
    <para>The behavior of the running daemon can be changed with
    <command>udevadm control</command>.</para>
  </refsect1>

  <refsect1><title>Options</title>
    <variablelist>
      <varlistentry>
        <term><option>--daemon</option></term>
        <listitem>
          <para>Detach and run in the background.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>--debug</option></term>
        <listitem>
          <para>Print debug messages to stderr.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>--children-max=</option></term>
        <listitem>
          <para>Limit the number of events executed in parallel.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>--exec-delay=</option></term>
        <listitem>

          <para>Delay the execution of RUN instruction by the given
          number of seconds. This option might be useful when
          debugging system crashes during coldplug caused by loading
          non-working kernel modules.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>--resolve-names=</option></term>
        <listitem>
          <para>Specify when systemd-udevd should resolve names of users and groups.
          When set to <option>early</option> (the default) names will be
          resolved when the rules are parsed.  When set to
          <option>late</option> names will be resolved for every event.
          When set to <option>never</option> names will never be resolved
          and all devices will be owned by root.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>--version</option></term>
        <listitem>
          <para>Print version number.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>--help</option></term>
        <listitem>
          <para>Print help text.</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1><title>Environment</title>
    <variablelist class='environment-variables'>
      <varlistentry>
        <term><varname>$UDEV_LOG=</varname></term>
        <listitem>
          <para>Set the logging priority.</para>
        </listitem>
      </varlistentry>
    </variablelist>
 </refsect1>

  <refsect1><title>Kernel command line</title>
    <variablelist class='kernel-commandline-options'>
      <para>Parameters starting with "rd." will be read when
      <command>systemd-udevd</command> is used in an initrd.</para>
      <varlistentry>
        <term><varname>udev.log-priority=</varname></term>
        <term><varname>rd.udev.log-priority=</varname></term>
        <listitem>
          <para>Set the logging priority.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>udev.children-max=</varname></term>
        <term><varname>rd.udev.children-max=</varname></term>
        <listitem>
          <para>Limit the number of events executed in parallel.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>udev.exec-delay=</varname></term>
        <term><varname>rd.udev.exec-delay=</varname></term>
        <listitem>
          <para>Delay the execution of RUN instruction by the given
          number of seconds. This option might be useful when
          debugging system crashes during coldplug caused by loading
          non-working kernel modules.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><varname>net.ifnames=</varname></term>
        <listitem>
          <para>Network interfaces are renamed to give them predictable names
          when possible. It is enabled by default, specifying 0 disables it.</para>
        </listitem>
      </varlistentry>
    </variablelist>
    <!-- when adding entries here, consider also adding them
         in kernel-command-line.xml -->
 </refsect1>

 <refsect1><title>Configuration file</title>
   <para>udev expects its main configuration file at <filename>/etc/udev/udev.conf</filename>.
   It consists of a set of variables allowing the user to override default udev values. All
   empty lines or lines beginning with '#' are ignored. The following variables can be
   set:</para>
   <variablelist>
     <varlistentry>
       <term><varname>udev_log</varname></term>
       <listitem>
         <para>The logging priority. Valid values are the numerical syslog priorities
         or their textual representations: <option>err</option>, <option>info</option>
         and <option>debug</option>.</para>
       </listitem>
     </varlistentry>
   </variablelist>
 </refsect1>

  <refsect1>
    <title>See Also</title>
    <para><citerefentry>
        <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum>
      </citerefentry>, <citerefentry>
        <refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum>
    </citerefentry></para>
  </refsect1>
</refentry>