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udevd: clarify worker exit status
[elogind.git] / udev / udevd.xml
1 <?xml version='1.0'?>
2 <?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
4   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
5
6 <refentry id="udevd">
7   <refentryinfo>
8     <title>udevd</title>
9     <productname>udev</productname>
10   </refentryinfo>
11
12   <refmeta>
13     <refentrytitle>udevd</refentrytitle>
14     <manvolnum>8</manvolnum>
15     <refmiscinfo class="version"></refmiscinfo>
16   </refmeta>
17
18   <refnamediv>
19     <refname>udevd</refname><refpurpose>event managing daemon</refpurpose>
20   </refnamediv>
21
22   <refsynopsisdiv>
23     <cmdsynopsis>
24       <command>udevd</command>
25       <arg><option>--daemon</option></arg>
26       <arg><option>--debug</option></arg>
27       <arg><option>--children-max=</option></arg>
28       <arg><option>--exec-delay=</option></arg>
29       <arg><option>--resolve-names=early|late|never</option></arg>
30       <arg><option>--version</option></arg>
31       <arg><option>--help</option></arg>
32     </cmdsynopsis>
33   </refsynopsisdiv>
34
35   <refsect1><title>Description</title>
36     <para>udevd listens to kernel uevents. For every event, udevd executes matching
37     instructions specified in udev rules. See <citerefentry>
38         <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum>
39       </citerefentry>.</para>
40     <para>On startup the content of the directory <filename>/lib/udev/devices</filename>
41     is copied to <filename>/dev</filename>. If kernel modules specify static device
42     nodes, these nodes are created even without a corresponding kernel device, to
43     allow on-demand loading of kernel modules. Matching permissions specified in udev
44     rules are applied to these static device nodes.</para>
45     <para>The behavior of the running daemon can be changed with
46     <command>udevadm control</command>.</para>
47   </refsect1>
48
49   <refsect1><title>Options</title>
50     <variablelist>
51       <varlistentry>
52         <term><option>--daemon</option></term>
53         <listitem>
54           <para>Detach and run in the background.</para>
55         </listitem>
56       </varlistentry>
57       <varlistentry>
58         <term><option>--debug</option></term>
59         <listitem>
60           <para>Print debug messages to stderr.</para>
61         </listitem>
62       </varlistentry>
63       <varlistentry>
64         <term><option>--children-max=</option></term>
65         <listitem>
66           <para>Limit the number of parallel executed events.</para>
67         </listitem>
68       </varlistentry>
69       <varlistentry>
70         <term><option>--exec-delay=</option></term>
71         <listitem>
72           <para>Number of seconds to delay the execution of RUN instructions.
73           This might be useful when debugging system crashes during coldplug
74           cause by loading non-working kernel modules.</para>
75         </listitem>
76       </varlistentry>
77       <varlistentry>
78         <term><option>--resolve-names=</option></term>
79         <listitem>
80           <para>Specify when udevd should resolve names of users and groups.
81           When set to <option>early</option> (the default) names will be
82           resolved when the rules are parsed.  When set to
83           <option>late</option> names will be resolved for every event.
84           When set to <option>never</option> names will never be resolved
85           and all devices will be owned by root.</para>
86         </listitem>
87       </varlistentry>
88       <varlistentry>
89         <term><option>--version</option></term>
90         <listitem>
91           <para>Print version number.</para>
92         </listitem>
93       </varlistentry>
94       <varlistentry>
95         <term><option>--help</option></term>
96         <listitem>
97           <para>Print help text.</para>
98         </listitem>
99       </varlistentry>
100     </variablelist>
101   </refsect1>
102
103   <refsect1><title>Environment</title>
104     <variablelist>
105       <varlistentry>
106         <term><varname>UDEV_LOG=</varname></term>
107         <listitem>
108           <para>Set the logging priority.</para>
109         </listitem>
110       </varlistentry>
111     </variablelist>
112  </refsect1>
113
114   <refsect1><title>Kernel command line</title>
115     <variablelist>
116       <varlistentry>
117         <term><varname>udev.log-priority=</varname></term>
118         <listitem>
119           <para>Set the logging priority.</para>
120         </listitem>
121       </varlistentry>
122       <varlistentry>
123         <term><varname>udev.children-max=</varname></term>
124         <listitem>
125           <para>Limit the number of parallel executed events.</para>
126         </listitem>
127       </varlistentry>
128       <varlistentry>
129         <term><varname>udev.exec-delay=</varname></term>
130         <listitem>
131           <para>Number of seconds to delay the execution of RUN instructions.
132           This might be useful when debugging system crashes during coldplug
133           cause by loading non-working kernel modules.</para>
134         </listitem>
135       </varlistentry>
136     </variablelist>
137  </refsect1>
138
139   <refsect1><title>Author</title>
140     <para>Written by Kay Sievers <email>kay.sievers@vrfy.org</email>.</para>
141   </refsect1>
142
143   <refsect1>
144     <title>See Also</title>
145     <para><citerefentry>
146         <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum>
147       </citerefentry>, <citerefentry>
148         <refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum>
149     </citerefentry></para>
150   </refsect1>
151 </refentry>