man/systemd-udevd.service.xml

   1 <?xml version='1.0'?>
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   3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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   5
   6 <refentry id="systemd-udevd.service"
   7           xmlns:xi="http://www.w3.org/2001/XInclude">
   8
   9   <refentryinfo>
  10     <title>systemd-udevd.service</title>
  11     <productname>systemd</productname>
  12     <authorgroup>
  13       <author>
  14         <contrib>Developer</contrib>
  15         <firstname>Kay</firstname>
  16         <surname>Sievers</surname>
  17         <email>kay@vrfy.org</email>
  18       </author>
  19     </authorgroup>
  20   </refentryinfo>
  21
  22   <refmeta>
  23     <refentrytitle>systemd-udevd.service</refentrytitle>
  24     <manvolnum>8</manvolnum>
  25   </refmeta>
  26
  27   <refnamediv>
  28     <refname>systemd-udevd.service</refname>
  29     <refname>systemd-udevd-control.socket</refname>
  30     <refname>systemd-udevd-kernel.socket</refname>
  31     <refname>systemd-udevd</refname>
  32     <refpurpose>Device event managing daemon</refpurpose>
  33   </refnamediv>
  34
  35   <refsynopsisdiv>
  36     <para><filename>systemd-udevd.service</filename></para>
  37     <para><filename>systemd-udevd-control.socket</filename></para>
  38     <para><filename>systemd-udevd-kernel.socket</filename></para>
  39
  40     <cmdsynopsis>
  41       <command>/usr/lib/systemd/systemd-udevd</command>
  42       <arg><option>--daemon</option></arg>
  43       <arg><option>--debug</option></arg>
  44       <arg><option>--children-max=</option></arg>
  45       <arg><option>--exec-delay=</option></arg>
  46       <arg><option>--event-timeout=</option></arg>
  47       <arg><option>--resolve-names=early|late|never</option></arg>
  48       <arg><option>--version</option></arg>
  49       <arg><option>--help</option></arg>
  50     </cmdsynopsis>
  51
  52   </refsynopsisdiv>
  53
  54   <refsect1><title>Description</title>
  55     <para><command>systemd-udevd</command> listens to kernel uevents.
  56     For every event, systemd-udevd executes matching instructions
  57     specified in udev rules. See <citerefentry>
  58     <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum>
  59     </citerefentry>.</para>
  60
  61     <para>The behavior of the running daemon can be changed
  62     dynamically with <command>udevadm control</command>, or
  63     configured using
  64     <citerefentry><refentrytitle>udev.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
  65     </para>
  66   </refsect1>
  67
  68   <refsect1><title>Options</title>
  69     <variablelist>
  70       <varlistentry>
  71         <term><option>--daemon</option></term>
  72         <listitem>
  73           <para>Detach and run in the background.</para>
  74         </listitem>
  75       </varlistentry>
  76
  77       <varlistentry>
  78         <term><option>--debug</option></term>
  79         <listitem>
  80           <para>Print debug messages to standard error.</para>
  81         </listitem>
  82       </varlistentry>
  83
  84       <varlistentry>
  85         <term><option>--children-max=</option></term>
  86         <listitem>
  87           <para>Limit the number of events executed in parallel.</para>
  88         </listitem>
  89       </varlistentry>
  90
  91       <varlistentry>
  92         <term><option>--exec-delay=</option></term>
  93         <listitem>
  94           <para>Delay the execution of <varname>RUN</varname>
  95           instructions by the given number of seconds. This option
  96           might be useful when debugging system crashes during
  97           coldplug caused by loading non-working kernel
  98           modules.</para>
  99         </listitem>
 100       </varlistentry>
 101
 102       <varlistentry>
 103         <term><option>--event-timeout=</option></term>
 104         <listitem>
 105           <para>Set the number of seconds to wait for events to finish. After
 106           this time the event will be terminated. The default is 30 seconds.</para>
 107         </listitem>
 108       </varlistentry>
 109
 110       <varlistentry>
 111         <term><option>--resolve-names=</option></term>
 112         <listitem>
 113           <para>Specify when systemd-udevd should resolve names of users and groups.
 114           When set to <option>early</option> (the default), names will be
 115           resolved when the rules are parsed.  When set to
 116           <option>late</option>, names will be resolved for every event.
 117           When set to <option>never</option>, names will never be resolved
 118           and all devices will be owned by root.</para>
 119         </listitem>
 120       </varlistentry>
 121
 122       <varlistentry>
 123         <term><option>--help</option></term>
 124
 125         <xi:include href="standard-options.xml" xpointer="help-text" />
 126       </varlistentry>
 127       <xi:include href="standard-options.xml" xpointer="version" />
 128     </variablelist>
 129   </refsect1>
 130
 131   <refsect1><title>Environment</title>
 132     <variablelist class='environment-variables'>
 133       <varlistentry>
 134         <term><varname>$UDEV_LOG=</varname></term>
 135         <listitem>
 136           <para>Set the logging priority.</para>
 137         </listitem>
 138       </varlistentry>
 139     </variablelist>
 140  </refsect1>
 141
 142   <refsect1><title>Kernel command line</title>
 143     <variablelist class='kernel-commandline-options'>
 144       <para>Parameters starting with "rd." will be read when
 145       <command>systemd-udevd</command> is used in an initrd.</para>
 146       <varlistentry>
 147         <term><varname>udev.log-priority=</varname></term>
 148         <term><varname>rd.udev.log-priority=</varname></term>
 149         <listitem>
 150           <para>Set the logging priority.</para>
 151         </listitem>
 152       </varlistentry>
 153       <varlistentry>
 154         <term><varname>udev.children-max=</varname></term>
 155         <term><varname>rd.udev.children-max=</varname></term>
 156         <listitem>
 157           <para>Limit the number of events executed in parallel.</para>
 158         </listitem>
 159       </varlistentry>
 160       <varlistentry>
 161         <term><varname>udev.exec-delay=</varname></term>
 162         <term><varname>rd.udev.exec-delay=</varname></term>
 163         <listitem>
 164           <para>Delay the execution of <varname>RUN</varname> instructions by the given
 165           number of seconds. This option might be useful when
 166           debugging system crashes during coldplug caused by loading
 167           non-working kernel modules.</para>
 168         </listitem>
 169       </varlistentry>
 170       <varlistentry>
 171         <term><varname>udev.event-timeout=</varname></term>
 172         <term><varname>rd.udev.event-timeout=</varname></term>
 173         <listitem>
 174           <para>Wait for events to finish up to the given number
 175           of seconds. This option might be useful if events are
 176           terminated due to kernel drivers taking too long to initialize.</para>
 177         </listitem>
 178       </varlistentry>
 179       <varlistentry>
 180         <term><varname>net.ifnames=</varname></term>
 181         <listitem>
 182           <para>Network interfaces are renamed to give them predictable names
 183           when possible. It is enabled by default; specifying 0 disables it.</para>
 184         </listitem>
 185       </varlistentry>
 186     </variablelist>
 187     <!-- when adding entries here, consider also adding them
 188          in kernel-command-line.xml -->
 189  </refsect1>
 190
 191   <refsect1>
 192     <title>See Also</title>
 193     <para>
 194       <citerefentry><refentrytitle>udev.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 195       <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 196       <citerefentry><refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 197     </para>
 198   </refsect1>
 199 </refentry>