man/systemd-udevd.service.xml

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   6 <refentry id="systemd-udevd.service">
   7   <refentryinfo>
   8     <title>systemd-udevd.service</title>
   9     <productname>systemd</productname>
  10     <authorgroup>
  11       <author>
  12         <contrib>Developer</contrib>
  13         <firstname>Kay</firstname>
  14         <surname>Sievers</surname>
  15         <email>kay@vrfy.org</email>
  16       </author>
  17     </authorgroup>
  18   </refentryinfo>
  19
  20   <refmeta>
  21     <refentrytitle>systemd-udevd.service</refentrytitle>
  22     <manvolnum>8</manvolnum>
  23     <refmiscinfo class="version"></refmiscinfo>
  24   </refmeta>
  25
  26   <refnamediv>
  27     <refname>systemd-udev.service</refname>
  28     <refname>systemd-udev-control.socket</refname>
  29     <refname>systemd-udev-kernel.socket</refname>
  30     <refname>systemd-udevd</refname>
  31     <refpurpose>Device event managing daemon</refpurpose>
  32   </refnamediv>
  33
  34   <refsynopsisdiv>
  35     <para><filename>systemd-udev.service</filename></para>
  36     <para><filename>systemd-udev-control.socket</filename></para>
  37     <para><filename>systemd-udev-kernel.socket</filename></para>
  38
  39     <cmdsynopsis>
  40       <command>/usr/lib/systemd/systemd-udevd</command>
  41       <arg><option>--daemon</option></arg>
  42       <arg><option>--debug</option></arg>
  43       <arg><option>--children-max=</option></arg>
  44       <arg><option>--exec-delay=</option></arg>
  45       <arg><option>--resolve-names=early|late|never</option></arg>
  46       <arg><option>--version</option></arg>
  47       <arg><option>--help</option></arg>
  48     </cmdsynopsis>
  49
  50   </refsynopsisdiv>
  51
  52   <refsect1><title>Description</title>
  53     <para>systemd-udevd listens to kernel uevents. For every event, systemd-udevd executes matching
  54     instructions specified in udev rules. See <citerefentry>
  55         <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum>
  56       </citerefentry>.</para>
  57     <para>The behavior of the running daemon can be changed with
  58     <command>udevadm control</command>.</para>
  59   </refsect1>
  60
  61   <refsect1><title>Options</title>
  62     <variablelist>
  63       <varlistentry>
  64         <term><option>--daemon</option></term>
  65         <listitem>
  66           <para>Detach and run in the background.</para>
  67         </listitem>
  68       </varlistentry>
  69       <varlistentry>
  70         <term><option>--debug</option></term>
  71         <listitem>
  72           <para>Print debug messages to stderr.</para>
  73         </listitem>
  74       </varlistentry>
  75       <varlistentry>
  76         <term><option>--children-max=</option></term>
  77         <listitem>
  78           <para>Limit the number of parallel executed events.</para>
  79         </listitem>
  80       </varlistentry>
  81       <varlistentry>
  82         <term><option>--exec-delay=</option></term>
  83         <listitem>
  84           <para>Number of seconds to delay the execution of RUN instructions.
  85           This might be useful when debugging system crashes during coldplug
  86           cause by loading non-working kernel modules.</para>
  87         </listitem>
  88       </varlistentry>
  89       <varlistentry>
  90         <term><option>--resolve-names=</option></term>
  91         <listitem>
  92           <para>Specify when systemd-udevd should resolve names of users and groups.
  93           When set to <option>early</option> (the default) names will be
  94           resolved when the rules are parsed.  When set to
  95           <option>late</option> names will be resolved for every event.
  96           When set to <option>never</option> names will never be resolved
  97           and all devices will be owned by root.</para>
  98         </listitem>
  99       </varlistentry>
 100       <varlistentry>
 101         <term><option>--version</option></term>
 102         <listitem>
 103           <para>Print version number.</para>
 104         </listitem>
 105       </varlistentry>
 106       <varlistentry>
 107         <term><option>--help</option></term>
 108         <listitem>
 109           <para>Print help text.</para>
 110         </listitem>
 111       </varlistentry>
 112     </variablelist>
 113   </refsect1>
 114
 115   <refsect1><title>Environment</title>
 116     <variablelist>
 117       <varlistentry>
 118         <term><varname>UDEV_LOG=</varname></term>
 119         <listitem>
 120           <para>Set the logging priority.</para>
 121         </listitem>
 122       </varlistentry>
 123     </variablelist>
 124  </refsect1>
 125
 126   <refsect1><title>Kernel command line</title>
 127     <variablelist>
 128       <para>The parameters starting with "rd.", will be read when udev is used in an initrd.</para>
 129       <varlistentry>
 130         <term><varname>udev.log-priority=</varname></term>
 131         <term><varname>rd.udev.log-priority=</varname></term>
 132         <listitem>
 133           <para>Set the logging priority.</para>
 134         </listitem>
 135       </varlistentry>
 136       <varlistentry>
 137         <term><varname>udev.children-max=</varname></term>
 138         <term><varname>rd.udev.children-max=</varname></term>
 139         <listitem>
 140           <para>Limit the number of parallel executed events.</para>
 141         </listitem>
 142       </varlistentry>
 143       <varlistentry>
 144         <term><varname>udev.exec-delay=</varname></term>
 145         <term><varname>rd.udev.exec-delay=</varname></term>
 146         <listitem>
 147           <para>Number of seconds to delay the execution of RUN instructions.
 148           This might be useful when debugging system crashes during coldplug
 149           cause by loading non-working kernel modules.</para>
 150         </listitem>
 151       </varlistentry>
 152     </variablelist>
 153  </refsect1>
 154
 155   <refsect1>
 156     <title>See Also</title>
 157     <para><citerefentry>
 158         <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum>
 159       </citerefentry>, <citerefentry>
 160         <refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum>
 161     </citerefentry></para>
 162   </refsect1>
 163 </refentry>