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514094f9 | 1 | <?xml version='1.0'?> |
63749b1a | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" |
12b42c76 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
420a506e | 4 | |
f48f7543 ZJS |
5 | <!-- |
6 | SPDX-License-Identifier: LGPL-2.1+ | |
f48f7543 ZJS |
7 | --> |
8 | ||
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9 | <refentry id="systemd-udevd.service" |
10 | xmlns:xi="http://www.w3.org/2001/XInclude"> | |
11 | ||
63749b1a | 12 | <refentryinfo> |
49408357 | 13 | <title>systemd-udevd.service</title> |
d3a2386d | 14 | <productname>systemd</productname> |
63749b1a | 15 | </refentryinfo> |
420a506e | 16 | |
63749b1a | 17 | <refmeta> |
bad1837c | 18 | <refentrytitle>systemd-udevd.service</refentrytitle> |
63749b1a | 19 | <manvolnum>8</manvolnum> |
63749b1a | 20 | </refmeta> |
420a506e | 21 | |
63749b1a | 22 | <refnamediv> |
51dfddc2 CG |
23 | <refname>systemd-udevd.service</refname> |
24 | <refname>systemd-udevd-control.socket</refname> | |
25 | <refname>systemd-udevd-kernel.socket</refname> | |
bad1837c | 26 | <refname>systemd-udevd</refname> |
b79f817b | 27 | <refpurpose>Device event managing daemon</refpurpose> |
63749b1a | 28 | </refnamediv> |
420a506e | 29 | |
63749b1a | 30 | <refsynopsisdiv> |
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31 | <para><filename>systemd-udevd.service</filename></para> |
32 | <para><filename>systemd-udevd-control.socket</filename></para> | |
33 | <para><filename>systemd-udevd-kernel.socket</filename></para> | |
b79f817b | 34 | |
63749b1a | 35 | <cmdsynopsis> |
12b42c76 | 36 | <command>/usr/lib/systemd/systemd-udevd</command> |
63749b1a | 37 | <arg><option>--daemon</option></arg> |
63749b1a | 38 | <arg><option>--debug</option></arg> |
9fa68615 KS |
39 | <arg><option>--children-max=</option></arg> |
40 | <arg><option>--exec-delay=</option></arg> | |
9719859c | 41 | <arg><option>--event-timeout=</option></arg> |
63749b1a | 42 | <arg><option>--resolve-names=early|late|never</option></arg> |
9fa68615 | 43 | <arg><option>--version</option></arg> |
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44 | <arg><option>--help</option></arg> |
45 | </cmdsynopsis> | |
b79f817b | 46 | |
63749b1a | 47 | </refsynopsisdiv> |
420a506e | 48 | |
63749b1a | 49 | <refsect1><title>Description</title> |
b8e8f0cb | 50 | <para><command>systemd-udevd</command> listens to kernel uevents. |
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51 | For every event, systemd-udevd executes matching instructions |
52 | specified in udev rules. See <citerefentry> | |
53 | <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum> | |
54 | </citerefentry>.</para> | |
55 | ||
203af57f ZJS |
56 | <para>The behavior of the daemon can be configured using |
57 | <citerefentry><refentrytitle>udev.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
81c7dd89 LP |
58 | its command line options, environment variables, and on the kernel |
59 | command line, or changed dynamically with <command>udevadm | |
203af57f | 60 | control</command>. |
6fc5a404 | 61 | </para> |
63749b1a | 62 | </refsect1> |
420a506e | 63 | |
63749b1a KS |
64 | <refsect1><title>Options</title> |
65 | <variablelist> | |
66 | <varlistentry> | |
a135d271 | 67 | <term><option>-d</option></term> |
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68 | <term><option>--daemon</option></term> |
69 | <listitem> | |
70 | <para>Detach and run in the background.</para> | |
71 | </listitem> | |
72 | </varlistentry> | |
dfdebb1b | 73 | |
63749b1a | 74 | <varlistentry> |
a135d271 | 75 | <term><option>-D</option></term> |
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76 | <term><option>--debug</option></term> |
77 | <listitem> | |
6db27428 | 78 | <para>Print debug messages to standard error.</para> |
9fa68615 KS |
79 | </listitem> |
80 | </varlistentry> | |
dfdebb1b | 81 | |
9fa68615 | 82 | <varlistentry> |
a135d271 | 83 | <term><option>-c=</option></term> |
9fa68615 | 84 | <term><option>--children-max=</option></term> |
63749b1a | 85 | <listitem> |
b8e8f0cb | 86 | <para>Limit the number of events executed in parallel.</para> |
63749b1a KS |
87 | </listitem> |
88 | </varlistentry> | |
dfdebb1b | 89 | |
63749b1a | 90 | <varlistentry> |
a135d271 | 91 | <term><option>-e=</option></term> |
9fa68615 | 92 | <term><option>--exec-delay=</option></term> |
63749b1a | 93 | <listitem> |
6db27428 | 94 | <para>Delay the execution of <varname>RUN</varname> |
66f756d4 | 95 | instructions by the given number of seconds. This option |
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96 | might be useful when debugging system crashes during |
97 | coldplug caused by loading non-working kernel | |
98 | modules.</para> | |
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99 | </listitem> |
100 | </varlistentry> | |
dfdebb1b | 101 | |
9719859c | 102 | <varlistentry> |
a135d271 | 103 | <term><option>-t=</option></term> |
9719859c HR |
104 | <term><option>--event-timeout=</option></term> |
105 | <listitem> | |
dd5eddd2 | 106 | <para>Set the number of seconds to wait for events to finish. After |
b938cb90 | 107 | this time, the event will be terminated. The default is 180 seconds.</para> |
9719859c HR |
108 | </listitem> |
109 | </varlistentry> | |
110 | ||
63749b1a | 111 | <varlistentry> |
a135d271 | 112 | <term><option>-N=</option></term> |
9fa68615 | 113 | <term><option>--resolve-names=</option></term> |
63749b1a | 114 | <listitem> |
f13b388f | 115 | <para>Specify when systemd-udevd should resolve names of users and groups. |
73e231ab | 116 | When set to <option>early</option> (the default), names will be |
63749b1a | 117 | resolved when the rules are parsed. When set to |
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118 | <option>late</option>, names will be resolved for every event. |
119 | When set to <option>never</option>, names will never be resolved | |
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120 | and all devices will be owned by root.</para> |
121 | </listitem> | |
122 | </varlistentry> | |
dfdebb1b | 123 | |
a135d271 | 124 | <xi:include href="standard-options.xml" xpointer="help" /> |
dfdebb1b | 125 | <xi:include href="standard-options.xml" xpointer="version" /> |
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126 | </variablelist> |
127 | </refsect1> | |
420a506e | 128 | |
8f7f1a2b | 129 | <refsect1><title>Kernel command line</title> |
ccc9a4f9 | 130 | <variablelist class='kernel-commandline-options'> |
b8e8f0cb ZJS |
131 | <para>Parameters starting with "rd." will be read when |
132 | <command>systemd-udevd</command> is used in an initrd.</para> | |
8f7f1a2b | 133 | <varlistentry> |
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134 | <term><varname>udev.log_priority=</varname></term> |
135 | <term><varname>rd.udev.log_priority=</varname></term> | |
8f7f1a2b | 136 | <listitem> |
f47ad593 | 137 | <para>Set the log level.</para> |
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138 | </listitem> |
139 | </varlistentry> | |
140 | <varlistentry> | |
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141 | <term><varname>udev.children_max=</varname></term> |
142 | <term><varname>rd.udev.children_max=</varname></term> | |
8f7f1a2b | 143 | <listitem> |
b8e8f0cb | 144 | <para>Limit the number of events executed in parallel.</para> |
8f7f1a2b KS |
145 | </listitem> |
146 | </varlistentry> | |
147 | <varlistentry> | |
1d84ad94 LP |
148 | <term><varname>udev.exec_delay=</varname></term> |
149 | <term><varname>rd.udev.exec_delay=</varname></term> | |
8f7f1a2b | 150 | <listitem> |
ed7e5fe3 | 151 | <para>Delay the execution of <varname>RUN</varname> instructions by the given |
b8e8f0cb ZJS |
152 | number of seconds. This option might be useful when |
153 | debugging system crashes during coldplug caused by loading | |
154 | non-working kernel modules.</para> | |
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155 | </listitem> |
156 | </varlistentry> | |
9719859c | 157 | <varlistentry> |
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158 | <term><varname>udev.event_timeout=</varname></term> |
159 | <term><varname>rd.udev.event_timeout=</varname></term> | |
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160 | <listitem> |
161 | <para>Wait for events to finish up to the given number | |
162 | of seconds. This option might be useful if events are | |
dd5eddd2 | 163 | terminated due to kernel drivers taking too long to initialize.</para> |
9719859c HR |
164 | </listitem> |
165 | </varlistentry> | |
0cf2d0d0 | 166 | <varlistentry> |
5a33334b | 167 | <term><varname>net.ifnames=</varname></term> |
0cf2d0d0 | 168 | <listitem> |
5a33334b | 169 | <para>Network interfaces are renamed to give them predictable names |
bcddd5bf | 170 | when possible. It is enabled by default; specifying 0 disables it.</para> |
0cf2d0d0 TG |
171 | </listitem> |
172 | </varlistentry> | |
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173 | <varlistentry> |
174 | <term><varname>net.naming-scheme=</varname></term> | |
175 | <listitem> | |
176 | <para>Network interfaces are renamed to give them predictable names when possible (unless | |
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177 | <varname>net.ifnames=0</varname> is specified, see above). The names are derived from various |
178 | device metadata fields. Newer versions of <filename>systemd-udevd.service</filename> take more of | |
179 | these fields into account, improving (and thus possibly changing) the names used for the same | |
180 | devices. With this kernel command line option it is possible to pick a specific version of this | |
181 | algorithm. It expects a naming scheme identifier as argument. Currently the following identifiers | |
182 | are known: <literal>v238</literal>, <literal>v239</literal>, <literal>v240</literal> which each | |
183 | implement the naming scheme that was the default in the indicated systemd version. In addition, | |
184 | <literal>latest</literal> may be used to designate the latest scheme known (to this particular | |
185 | version of <filename>systemd-udevd.service</filename>).</para> | |
186 | ||
187 | <para>Note that selecting a specific scheme is not sufficient to fully stabilize interface naming: | |
188 | the naming is generally derived from driver attributes exposed by the kernel. As the kernel is | |
189 | updated, previously missing attributes <filename>systemd-udevd.service</filename> is checking might | |
190 | appear, which affects older name derivation algorithms, too.</para> | |
f7e81fd9 LP |
191 | </listitem> |
192 | </varlistentry> | |
63749b1a | 193 | </variablelist> |
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194 | <!-- when adding entries here, consider also adding them |
195 | in kernel-command-line.xml --> | |
63749b1a | 196 | </refsect1> |
7b86ada7 | 197 | |
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198 | <refsect1> |
199 | <title>See Also</title> | |
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200 | <para> |
201 | <citerefentry><refentrytitle>udev.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
202 | <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>, | |
203 | <citerefentry><refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
204 | </para> | |
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205 | </refsect1> |
206 | </refentry> |