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>-d</option></term>
  93         <term><option>--daemon</option></term>
  94         <listitem>
  95           <para>Detach and run in the background.</para>
  96         </listitem>
  97       </varlistentry>
  98
  99       <varlistentry>
 100         <term><option>-D</option></term>
 101         <term><option>--debug</option></term>
 102         <listitem>
 103           <para>Print debug messages to standard error.</para>
 104         </listitem>
 105       </varlistentry>
 106
 107       <varlistentry>
 108         <term><option>-c=</option></term>
 109         <term><option>--children-max=</option></term>
 110         <listitem>
 111           <para>Limit the number of events executed in parallel.</para>
 112         </listitem>
 113       </varlistentry>
 114
 115       <varlistentry>
 116         <term><option>-e=</option></term>
 117         <term><option>--exec-delay=</option></term>
 118         <listitem>
 119           <para>Delay the execution of <varname>RUN</varname>
 120           instructions by the given number of seconds. This option
 121           might be useful when debugging system crashes during
 122           coldplug caused by loading non-working kernel
 123           modules.</para>
 124         </listitem>
 125       </varlistentry>
 126
 127       <varlistentry>
 128         <term><option>-t=</option></term>
 129         <term><option>--event-timeout=</option></term>
 130         <listitem>
 131           <para>Set the number of seconds to wait for events to finish. After
 132           this time, the event will be terminated. The default is 180 seconds.</para>
 133         </listitem>
 134       </varlistentry>
 135
 136       <varlistentry>
 137         <term><option>-N=</option></term>
 138         <term><option>--resolve-names=</option></term>
 139         <listitem>
 140           <para>Specify when systemd-udevd should resolve names of users and groups.
 141           When set to <option>early</option> (the default), names will be
 142           resolved when the rules are parsed.  When set to
 143           <option>late</option>, names will be resolved for every event.
 144           When set to <option>never</option>, names will never be resolved
 145           and all devices will be owned by root.</para>
 146         </listitem>
 147       </varlistentry>
 148
 149       <xi:include href="standard-options.xml" xpointer="help" />
 150       <xi:include href="standard-options.xml" xpointer="version" />
 151     </variablelist>
 152   </refsect1>
 153
 154   <refsect1><title>Kernel command line</title>
 155     <variablelist class='kernel-commandline-options'>
 156       <para>Parameters starting with "rd." will be read when
 157       <command>systemd-udevd</command> is used in an initrd.</para>
 158       <varlistentry>
 159         <term><varname>udev.log_priority=</varname></term>
 160         <term><varname>rd.udev.log_priority=</varname></term>
 161         <listitem>
 162           <para>Set the log level.</para>
 163         </listitem>
 164       </varlistentry>
 165       <varlistentry>
 166         <term><varname>udev.children_max=</varname></term>
 167         <term><varname>rd.udev.children_max=</varname></term>
 168         <listitem>
 169           <para>Limit the number of events executed in parallel.</para>
 170         </listitem>
 171       </varlistentry>
 172       <varlistentry>
 173         <term><varname>udev.exec_delay=</varname></term>
 174         <term><varname>rd.udev.exec_delay=</varname></term>
 175         <listitem>
 176           <para>Delay the execution of <varname>RUN</varname> instructions by the given
 177           number of seconds. This option might be useful when
 178           debugging system crashes during coldplug caused by loading
 179           non-working kernel modules.</para>
 180         </listitem>
 181       </varlistentry>
 182       <varlistentry>
 183         <term><varname>udev.event_timeout=</varname></term>
 184         <term><varname>rd.udev.event_timeout=</varname></term>
 185         <listitem>
 186           <para>Wait for events to finish up to the given number
 187           of seconds. This option might be useful if events are
 188           terminated due to kernel drivers taking too long to initialize.</para>
 189         </listitem>
 190       </varlistentry>
 191       <varlistentry>
 192         <term><varname>net.ifnames=</varname></term>
 193         <listitem>
 194           <para>Network interfaces are renamed to give them predictable names
 195           when possible. It is enabled by default; specifying 0 disables it.</para>
 196         </listitem>
 197       </varlistentry>
 198     </variablelist>
 199     <!-- when adding entries here, consider also adding them
 200          in kernel-command-line.xml -->
 201  </refsect1>
 202
 203   <refsect1>
 204     <title>See Also</title>
 205     <para>
 206       <citerefentry><refentrytitle>udev.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 207       <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 208       <citerefentry><refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 209     </para>
 210   </refsect1>
 211 </refentry>