man/systemd-udevd.service.xml

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