man/systemd-udevd.service.xml

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  10   Copyright 2010-2013 Kay Sievers
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  25
  26 <refentry id="systemd-udevd.service"
  27           xmlns:xi="http://www.w3.org/2001/XInclude">
  28
  29   <refentryinfo>
  30     <title>systemd-udevd.service</title>
  31     <productname>systemd</productname>
  32     <authorgroup>
  33       <author>
  34         <contrib>Developer</contrib>
  35         <firstname>Kay</firstname>
  36         <surname>Sievers</surname>
  37         <email>kay@vrfy.org</email>
  38       </author>
  39     </authorgroup>
  40   </refentryinfo>
  41
  42   <refmeta>
  43     <refentrytitle>systemd-udevd.service</refentrytitle>
  44     <manvolnum>8</manvolnum>
  45   </refmeta>
  46
  47   <refnamediv>
  48     <refname>systemd-udevd.service</refname>
  49     <refname>systemd-udevd-control.socket</refname>
  50     <refname>systemd-udevd-kernel.socket</refname>
  51     <refname>systemd-udevd</refname>
  52     <refpurpose>Device event managing daemon</refpurpose>
  53   </refnamediv>
  54
  55   <refsynopsisdiv>
  56     <para><filename>systemd-udevd.service</filename></para>
  57     <para><filename>systemd-udevd-control.socket</filename></para>
  58     <para><filename>systemd-udevd-kernel.socket</filename></para>
  59
  60     <cmdsynopsis>
  61       <command>/usr/lib/systemd/systemd-udevd</command>
  62       <arg><option>--daemon</option></arg>
  63       <arg><option>--debug</option></arg>
  64       <arg><option>--children-max=</option></arg>
  65       <arg><option>--exec-delay=</option></arg>
  66       <arg><option>--event-timeout=</option></arg>
  67       <arg><option>--resolve-names=early|late|never</option></arg>
  68       <arg><option>--version</option></arg>
  69       <arg><option>--help</option></arg>
  70     </cmdsynopsis>
  71
  72   </refsynopsisdiv>
  73
  74   <refsect1><title>Description</title>
  75     <para><command>systemd-udevd</command> listens to kernel uevents.
  76     For every event, systemd-udevd executes matching instructions
  77     specified in udev rules. See <citerefentry>
  78     <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum>
  79     </citerefentry>.</para>
  80
  81     <para>The behavior of the daemon can be configured using
  82     <citerefentry><refentrytitle>udev.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  83     its command line options, environment variables, and on the kernel
  84     command line, or changed dynamically with <command>udevadm
  85     control</command>.
  86     </para>
  87   </refsect1>
  88
  89   <refsect1><title>Options</title>
  90     <variablelist>
  91       <varlistentry>
  92         <term><option>--daemon</option></term>
  93         <listitem>
  94           <para>Detach and run in the background.</para>
  95         </listitem>
  96       </varlistentry>
  97
  98       <varlistentry>
  99         <term><option>--debug</option></term>
 100         <listitem>
 101           <para>Print debug messages to standard error.</para>
 102         </listitem>
 103       </varlistentry>
 104
 105       <varlistentry>
 106         <term><option>--children-max=</option></term>
 107         <listitem>
 108           <para>Limit the number of events executed in parallel.</para>
 109         </listitem>
 110       </varlistentry>
 111
 112       <varlistentry>
 113         <term><option>--exec-delay=</option></term>
 114         <listitem>
 115           <para>Delay the execution of <varname>RUN</varname>
 116           instructions by the given number of seconds. This option
 117           might be useful when debugging system crashes during
 118           coldplug caused by loading non-working kernel
 119           modules.</para>
 120         </listitem>
 121       </varlistentry>
 122
 123       <varlistentry>
 124         <term><option>--event-timeout=</option></term>
 125         <listitem>
 126           <para>Set the number of seconds to wait for events to finish. After
 127           this time, the event will be terminated. The default is 180 seconds.</para>
 128         </listitem>
 129       </varlistentry>
 130
 131       <varlistentry>
 132         <term><option>--resolve-names=</option></term>
 133         <listitem>
 134           <para>Specify when systemd-udevd should resolve names of users and groups.
 135           When set to <option>early</option> (the default), names will be
 136           resolved when the rules are parsed.  When set to
 137           <option>late</option>, names will be resolved for every event.
 138           When set to <option>never</option>, names will never be resolved
 139           and all devices will be owned by root.</para>
 140         </listitem>
 141       </varlistentry>
 142
 143       <varlistentry>
 144         <term><option>--help</option></term>
 145
 146         <xi:include href="standard-options.xml" xpointer="help-text" />
 147       </varlistentry>
 148       <xi:include href="standard-options.xml" xpointer="version" />
 149     </variablelist>
 150   </refsect1>
 151
 152   <refsect1><title>Kernel command line</title>
 153     <variablelist class='kernel-commandline-options'>
 154       <para>Parameters starting with "rd." will be read when
 155       <command>systemd-udevd</command> is used in an initrd.</para>
 156       <varlistentry>
 157         <term><varname>udev.log_priority=</varname></term>
 158         <term><varname>rd.udev.log_priority=</varname></term>
 159         <listitem>
 160           <para>Set the log level.</para>
 161         </listitem>
 162       </varlistentry>
 163       <varlistentry>
 164         <term><varname>udev.children_max=</varname></term>
 165         <term><varname>rd.udev.children_max=</varname></term>
 166         <listitem>
 167           <para>Limit the number of events executed in parallel.</para>
 168         </listitem>
 169       </varlistentry>
 170       <varlistentry>
 171         <term><varname>udev.exec_delay=</varname></term>
 172         <term><varname>rd.udev.exec_delay=</varname></term>
 173         <listitem>
 174           <para>Delay the execution of <varname>RUN</varname> instructions by the given
 175           number of seconds. This option might be useful when
 176           debugging system crashes during coldplug caused by loading
 177           non-working kernel modules.</para>
 178         </listitem>
 179       </varlistentry>
 180       <varlistentry>
 181         <term><varname>udev.event_timeout=</varname></term>
 182         <term><varname>rd.udev.event_timeout=</varname></term>
 183         <listitem>
 184           <para>Wait for events to finish up to the given number
 185           of seconds. This option might be useful if events are
 186           terminated due to kernel drivers taking too long to initialize.</para>
 187         </listitem>
 188       </varlistentry>
 189       <varlistentry>
 190         <term><varname>net.ifnames=</varname></term>
 191         <listitem>
 192           <para>Network interfaces are renamed to give them predictable names
 193           when possible. It is enabled by default; specifying 0 disables it.</para>
 194         </listitem>
 195       </varlistentry>
 196     </variablelist>
 197     <!-- when adding entries here, consider also adding them
 198          in kernel-command-line.xml -->
 199  </refsect1>
 200
 201   <refsect1>
 202     <title>See Also</title>
 203     <para>
 204       <citerefentry><refentrytitle>udev.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 205       <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 206       <citerefentry><refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 207     </para>
 208   </refsect1>
 209 </refentry>