man/systemd-udevd.service.xml

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