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| <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
| "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
| <!-- SPDX-License-Identifier: LGPL-2.1-or-later --> |
| |
| <refentry id="udevadm" |
| xmlns:xi="http://www.w3.org/2001/XInclude"> |
| |
| <refentryinfo> |
| <title>udevadm</title> |
| <productname>systemd</productname> |
| </refentryinfo> |
| |
| <refmeta> |
| <refentrytitle>udevadm</refentrytitle> |
| <manvolnum>8</manvolnum> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>udevadm</refname><refpurpose>udev management tool</refpurpose> |
| </refnamediv> |
| |
| <refsynopsisdiv> |
| <cmdsynopsis> |
| <command>udevadm</command> |
| <arg><option>--debug</option></arg> |
| <arg><option>--version</option></arg> |
| <arg><option>--help</option></arg> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>udevadm info <optional>options</optional> <optional>devpath</optional></command> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>udevadm trigger <optional>options</optional> <optional>devpath</optional></command> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>udevadm settle <optional>options</optional></command> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>udevadm control <replaceable>option</replaceable></command> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>udevadm monitor <optional>options</optional></command> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>udevadm test <optional>options</optional> <replaceable>devpath</replaceable></command> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>udevadm test-builtin <optional>options</optional> <replaceable>command</replaceable> <replaceable>devpath</replaceable></command> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>udevadm wait <optional>options</optional> <replaceable>device|syspath</replaceable></command> |
| </cmdsynopsis> |
| <cmdsynopsis> |
| <command>udevadm lock <optional>options</optional> <replaceable>command</replaceable></command> |
| </cmdsynopsis> |
| </refsynopsisdiv> |
| |
| <refsect1><title>Description</title> |
| <para><command>udevadm</command> expects a command and command |
| specific options. It controls the runtime behavior of |
| <command>systemd-udevd</command>, requests kernel events, manages |
| the event queue, and provides simple debugging mechanisms.</para> |
| </refsect1> |
| |
| <refsect1><title>Options</title> |
| <variablelist> |
| <varlistentry> |
| <term><option>-d</option></term> |
| <term><option>--debug</option></term> |
| <listitem> |
| <para>Print debug messages to standard error. This option is implied in <command>udevadm test</command> and |
| <command>udevadm test-builtin</command> commands.</para> |
| </listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| </variablelist> |
| |
| <refsect2><title>udevadm info |
| <arg choice="opt"><replaceable>options</replaceable></arg> |
| <arg choice="opt" rep="repeat"><replaceable>devpath</replaceable>|<replaceable>file</replaceable>|<replaceable>unit</replaceable></arg> |
| </title> |
| |
| <para>Query the udev database for device information.</para> |
| |
| <para>Positional arguments should be used to specify one or more devices. Each one may be a device name |
| (in which case it must start with <filename>/dev/</filename>), a sys path (in which case it must start |
| with <filename>/sys/</filename>), or a systemd device unit name (in which case it must end with |
| <literal>.device</literal>, see |
| <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>). |
| </para> |
| |
| <variablelist> |
| <varlistentry> |
| <term><option>-q</option></term> |
| <term><option>--query=<replaceable>TYPE</replaceable></option></term> |
| <listitem> |
| <para>Query the database for the specified type of device data. |
| Valid <replaceable>TYPE</replaceable>s are: |
| <constant>name</constant>, <constant>symlink</constant>, |
| <constant>path</constant>, <constant>property</constant>, |
| <constant>all</constant>.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--property=<replaceable>NAME</replaceable></option></term> |
| <listitem> |
| <para>When showing device properties using the <option>--query=property</option> |
| option, limit display to properties specified in the argument. The argument should |
| be a comma-separated list of property names. If not specified, all known properties |
| are shown.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--value</option></term> |
| <listitem> |
| <para>When showing device properties using the <option>--query=property</option> |
| option, print only their values, and skip the property name and <literal>=</literal>.</para> |
| <para>Cannot be used together with <option>-x/--export</option> or |
| <option>-P/--export-prefix</option>.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-p</option></term> |
| <term><option>--path=<replaceable>DEVPATH</replaceable></option></term> |
| <listitem> |
| <para>The <filename>/sys/</filename> path of the device to query, e.g. |
| <filename><optional>/sys/</optional>/class/block/sda</filename>. This option is an alternative to |
| the positional argument with a <filename>/sys/</filename> prefix. <command>udevadm info |
| --path=/class/block/sda</command> is equivalent to <command>udevadm info |
| /sys/class/block/sda</command>.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-n</option></term> |
| <term><option>--name=<replaceable>FILE</replaceable></option></term> |
| <listitem> |
| <para>The name of the device node or a symlink to query, |
| e.g. <filename><optional>/dev/</optional>/sda</filename>. This option is an alternative to the |
| positional argument with a <filename>/dev/</filename> prefix. <command>udevadm info |
| --name=sda</command> is equivalent to <command>udevadm info /dev/sda</command>.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-r</option></term> |
| <term><option>--root</option></term> |
| <listitem> |
| <para>Print absolute paths in <command>name</command> or <command>symlink</command> |
| query.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-a</option></term> |
| <term><option>--attribute-walk</option></term> |
| <listitem> |
| <para>Print all sysfs properties of the specified device that can be used |
| in udev rules to match the specified device. It prints all devices |
| along the chain, up to the root of sysfs that can be used in udev rules.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-t</option></term> |
| <term><option>--tree</option></term> |
| <listitem> |
| <para>Display a sysfs tree. This recursively iterates through the sysfs hierarchy and displays it |
| in a tree structure. If a path is specified only the subtree below and its parent directories are |
| shown. This will show both device and subsystem items.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-x</option></term> |
| <term><option>--export</option></term> |
| <listitem> |
| <para>Print output as key/value pairs. Values are enclosed in single quotes. |
| This takes effects only when <option>--query=property</option> or |
| <option>--device-id-of-file=<replaceable>FILE</replaceable></option> is specified.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-P</option></term> |
| <term><option>--export-prefix=<replaceable>NAME</replaceable></option></term> |
| <listitem> |
| <para>Add a prefix to the key name of exported values. |
| This implies <option>--export</option>.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-d</option></term> |
| <term><option>--device-id-of-file=<replaceable>FILE</replaceable></option></term> |
| <listitem> |
| <para>Print major/minor numbers of the underlying device, where the file lives on. |
| If this is specified, all positional arguments are ignored.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-e</option></term> |
| <term><option>--export-db</option></term> |
| <listitem> |
| <para>Export the content of the udev database.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-c</option></term> |
| <term><option>--cleanup-db</option></term> |
| <listitem> |
| <para>Cleanup the udev database.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-w<optional>SECONDS</optional></option></term> |
| <term><option>--wait-for-initialization<optional>=SECONDS</optional></option></term> |
| <listitem> |
| <para>Wait for device to be initialized. If argument <replaceable>SECONDS</replaceable> |
| is not specified, the default is to wait forever.</para> |
| </listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| <xi:include href="standard-options.xml" xpointer="no-pager" /> |
| </variablelist> |
| |
| <para>The generated output shows the current device database entry in a terse format. Each line shown |
| is prefixed with one of the following characters:</para> |
| |
| <table> |
| <title><command>udevadm info</command> output prefixes</title> |
| <tgroup cols='2' align='left' colsep='1' rowsep='1'> |
| <colspec colname="prefix" /> |
| <colspec colname="meaning" /> |
| <thead> |
| <row> |
| <entry>Prefix</entry> |
| <entry>Meaning</entry> |
| </row> |
| </thead> |
| <tbody> |
| <row> |
| <entry><literal>P:</literal></entry> |
| <entry>Device path in <filename>/sys/</filename></entry> |
| </row> |
| <row> |
| <entry><literal>M:</literal></entry> |
| <entry>Device name in <filename>/sys/</filename> (i.e. the last component of <literal>P:</literal>)</entry> |
| </row> |
| <row> |
| <entry><literal>R:</literal></entry> |
| <entry>Device number in <filename>/sys/</filename> (i.e. the numeric suffix of the last component of <literal>P:</literal>)</entry> |
| </row> |
| <row> |
| <entry><literal>U:</literal></entry> |
| <entry>Kernel subsystem</entry> |
| </row> |
| <row> |
| <entry><literal>T:</literal></entry> |
| <entry>Kernel device type within subsystem</entry> |
| </row> |
| <row> |
| <entry><literal>D:</literal></entry> |
| <entry>Kernel device node major/minor</entry> |
| </row> |
| <row> |
| <entry><literal>I:</literal></entry> |
| <entry>Network interface index</entry> |
| </row> |
| <row> |
| <entry><literal>N:</literal></entry> |
| <entry>Kernel device node name</entry> |
| </row> |
| <row> |
| <entry><literal>L:</literal></entry> |
| <entry>Device node symlink priority</entry> |
| </row> |
| <row> |
| <entry><literal>S:</literal></entry> |
| <entry>Device node symlink</entry> |
| </row> |
| <row> |
| <entry><literal>Q:</literal></entry> |
| <entry>Block device sequence number (DISKSEQ)</entry> |
| </row> |
| <row> |
| <entry><literal>V:</literal></entry> |
| <entry>Attached driver</entry> |
| </row> |
| <row> |
| <entry><literal>E:</literal></entry> |
| <entry>Device property</entry> |
| </row> |
| </tbody> |
| </tgroup> |
| </table> |
| </refsect2> |
| |
| <refsect2><title>udevadm trigger |
| <arg choice="opt"><replaceable>options</replaceable></arg> |
| <arg choice="opt"><replaceable>devpath</replaceable>|<replaceable>file</replaceable>|<replaceable>unit</replaceable></arg> |
| </title> |
| <para>Request device events from the kernel. Primarily used to replay events at system coldplug time.</para> |
| |
| <para>Takes device specifications as positional arguments. See the description of <command>info</command> |
| above.</para> |
| |
| <variablelist> |
| <varlistentry> |
| <term><option>-v</option></term> |
| <term><option>--verbose</option></term> |
| <listitem> |
| <para>Print the list of devices which will be triggered.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-n</option></term> |
| <term><option>--dry-run</option></term> |
| <listitem> |
| <para>Do not actually trigger the event.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-q</option></term> |
| <term><option>--quiet</option></term> |
| <listitem> |
| <para>Suppress error logging in triggering events.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-t</option></term> |
| <term><option>--type=<replaceable>TYPE</replaceable></option></term> |
| <listitem> |
| <para>Trigger a specific type of devices. Valid types are <literal>all</literal>, |
| <literal>devices</literal>, and <literal>subsystems</literal>. The default value is |
| <literal>devices</literal>.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-c</option></term> |
| <term><option>--action=<replaceable>ACTION</replaceable></option></term> |
| <listitem> |
| <para>Type of event to be triggered. Possible actions are <literal>add</literal>, |
| <literal>remove</literal>, <literal>change</literal>, <literal>move</literal>, |
| <literal>online</literal>, <literal>offline</literal>, <literal>bind</literal>, |
| and <literal>unbind</literal>. Also, the special value <literal>help</literal> can be used |
| to list the possible actions. The default value is <literal>change</literal>. |
| </para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--prioritized-subsystem=<replaceable>SUBSYSTEM<optional>,<replaceable>SUBSYSTEM</replaceable>…</optional></replaceable></option></term> |
| <listitem> |
| <para>Takes a comma separated list of subsystems. When triggering events for devices, the |
| devices from the specified subsystems and their parents are triggered first. For example, |
| if <option>--prioritized-subsystem=block,net</option>, then firstly all block devices and |
| their parents are triggered, in the next all network devices and their parents are |
| triggered, and lastly the other devices are triggered. This option can be specified |
| multiple times, and in that case the lists of the subsystems will be merged. That is, |
| <option>--prioritized-subsystem=block --prioritized-subsystem=net</option> is equivalent to |
| <option>--prioritized-subsystem=block,net</option>.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-s</option></term> |
| <term><option>--subsystem-match=<replaceable>SUBSYSTEM</replaceable></option></term> |
| <listitem> |
| <para>Trigger events for devices which belong to a |
| matching subsystem. This option supports shell style pattern matching. |
| When this option is specified more than once, then each matching result is ORed, that is, |
| all the devices in each subsystem are triggered.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-S</option></term> |
| <term><option>--subsystem-nomatch=<replaceable>SUBSYSTEM</replaceable></option></term> |
| <listitem> |
| <para>Do not trigger events for devices which belong to a matching subsystem. This option |
| supports shell style pattern matching. When this option is specified more than once, |
| then each matching result is ANDed, that is, devices which do not match all specified |
| subsystems are triggered.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-a</option></term> |
| <term><option>--attr-match=<replaceable>ATTRIBUTE</replaceable>=<replaceable>VALUE</replaceable></option></term> |
| <listitem> |
| <para>Trigger events for devices with a matching sysfs attribute. If a value is specified along |
| with the attribute name, the content of the attribute is matched against the given value using |
| shell style pattern matching. If no value is specified, the existence of the sysfs attribute is |
| checked. When this option is specified multiple times, then each matching result is ANDed, |
| that is, only devices which have all specified attributes are triggered.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-A</option></term> |
| <term><option>--attr-nomatch=<replaceable>ATTRIBUTE</replaceable>=<replaceable>VALUE</replaceable></option></term> |
| <listitem> |
| <para>Do not trigger events for devices with a matching sysfs attribute. If a value is specified |
| along with the attribute name, the content of the attribute is matched against the given value |
| using shell style pattern matching. If no value is specified, the existence of the sysfs attribute |
| is checked. When this option is specified multiple times, then each matching result is ANDed, |
| that is, only devices which have none of the specified attributes are triggered.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-p</option></term> |
| <term><option>--property-match=<replaceable>PROPERTY</replaceable>=<replaceable>VALUE</replaceable></option></term> |
| <listitem> |
| <para>Trigger events for devices with a matching property value. This option supports shell style |
| pattern matching. When this option is specified more than once, then each matching result is ORed, |
| that is, devices which have one of the specified properties are triggered.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-g</option></term> |
| <term><option>--tag-match=<replaceable>TAG</replaceable></option></term> |
| <listitem> |
| <para>Trigger events for devices with a matching tag. When this option is specified multiple times, |
| then each matching result is ANDed, that is, devices which have all specified tags are triggered.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-y</option></term> |
| <term><option>--sysname-match=<replaceable>NAME</replaceable></option></term> |
| <listitem> |
| <para>Trigger events for devices for which the last component (i.e. the filename) of the |
| <filename>/sys/</filename> path matches the specified <replaceable>PATH</replaceable>. This option |
| supports shell style pattern matching. When this option is specified more than once, then each |
| matching result is ORed, that is, all devices which have any of the specified |
| <replaceable>NAME</replaceable> are triggered.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--name-match=<replaceable>NAME</replaceable></option></term> |
| <listitem> |
| <para>Trigger events for devices with a matching device path. When this option is specified more than once, |
| then each matching result is ORed, that is, all specified devices are triggered.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-b</option></term> |
| <term><option>--parent-match=<replaceable>SYSPATH</replaceable></option></term> |
| <listitem> |
| <para>Trigger events for all children of a given device. When this option is specified more than once, |
| then each matching result is ORed, that is, all children of each specified device are triggered.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--initialized-match</option></term> |
| <term><option>--initialized-nomatch</option></term> |
| <listitem> |
| <para>When <option>--initialized-match</option> is specified, trigger events for devices |
| that are already initialized by <command>systemd-udevd</command>, and skip devices that |
| are not initialized yet.</para> |
| <para>When <option>--initialized-nomatch</option> is specified, trigger events for devices |
| that are not initialized by <command>systemd-udevd</command> yet, and skip devices that |
| are already initialized.</para> |
| <para>Typically, it is essential that applications which intend to use such a match, make |
| sure a suitable udev rule is installed that sets at least one property on devices that |
| shall be matched. See also Initialized Devices section below for more details.</para> |
| <para>WARNING: <option>--initialized-nomatch</option> can potentially save a significant |
| amount of time compared to re-triggering all devices in the system and e.g. can be used to |
| optimize boot time. However, this is not safe to be used in a boot sequence in general. |
| Especially, when udev rules for a device depend on its parent devices (e.g. |
| <literal>ATTRS</literal> or <literal>IMPORT{parent}</literal> keys, see |
| <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| for more details), the final state of the device becomes easily unstable with this option. |
| </para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-w</option></term> |
| <term><option>--settle</option></term> |
| <listitem> |
| <para>Apart from triggering events, also waits for those events to |
| finish. Note that this is different from calling <command>udevadm |
| settle</command>. <command>udevadm settle</command> waits for all |
| events to finish. This option only waits for events triggered by |
| the same command to finish.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--uuid</option></term> |
| <listitem> |
| <para>Trigger the synthetic device events, and associate a randomized UUID with each. These UUIDs |
| are printed to standard output, one line for each event. These UUIDs are included in the uevent |
| environment block (in the <literal>SYNTH_UUID=</literal> property) and may be used to track |
| delivery of the generated events.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--wait-daemon[=<replaceable>SECONDS</replaceable>]</option></term> |
| <listitem> |
| <para>Before triggering uevents, wait for systemd-udevd daemon to be initialized. |
| Optionally takes timeout value. Default timeout is 5 seconds. This is equivalent to invoke |
| invoking <command>udevadm control --ping</command> before <command>udevadm trigger</command>.</para> |
| </listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| </variablelist> |
| |
| <para>In addition, optional positional arguments can be used |
| to specify device names or sys paths. They must start with |
| <filename>/dev/</filename> or <filename>/sys/</filename> |
| respectively.</para> |
| </refsect2> |
| |
| <refsect2><title>udevadm settle |
| <arg choice="opt"><replaceable>options</replaceable></arg> |
| </title> |
| <para>Watches the udev event queue, and exits if all current events are handled.</para> |
| <variablelist> |
| <varlistentry> |
| <term><option>-t</option></term> |
| <term><option>--timeout=<replaceable>SECONDS</replaceable></option></term> |
| <listitem> |
| <para>Maximum number of seconds to wait for the event |
| queue to become empty. The default value is 120 seconds. A |
| value of 0 will check if the queue is empty and always |
| return immediately. A non-zero value will return an exit |
| code of 0 if queue became empty before timeout was reached, |
| non-zero otherwise.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-E</option></term> |
| <term><option>--exit-if-exists=<replaceable>FILE</replaceable></option></term> |
| <listitem> |
| <para>Stop waiting if file exists.</para> |
| </listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| </variablelist> |
| |
| <para>See |
| <citerefentry><refentrytitle>systemd-udev-settle.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| for more information.</para> |
| </refsect2> |
| |
| <refsect2><title>udevadm control <replaceable>option</replaceable></title> |
| <para>Modify the internal state of the running udev daemon.</para> |
| <variablelist> |
| <varlistentry> |
| <term><option>-e</option></term> |
| <term><option>--exit</option></term> |
| <listitem> |
| <para>Signal and wait for systemd-udevd to exit. No option except for |
| <option>--timeout</option> can be specified after this option. |
| Note that <filename>systemd-udevd.service</filename> contains |
| <option>Restart=always</option> and so as a result, this option restarts systemd-udevd. |
| If you want to stop <filename>systemd-udevd.service</filename>, please use the following: |
| <programlisting>systemctl stop systemd-udevd-control.socket systemd-udevd-kernel.socket systemd-udevd.service</programlisting> |
| </para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-l</option></term> |
| <term><option>--log-level=<replaceable>value</replaceable></option></term> |
| <listitem> |
| <para>Set the internal log level of |
| <filename>systemd-udevd</filename>. Valid values are the |
| numerical syslog priorities or their textual |
| representations: <option>emerg</option>, |
| <option>alert</option>, <option>crit</option>, |
| <option>err</option>, <option>warning</option>, |
| <option>notice</option>, <option>info</option>, and |
| <option>debug</option>.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-s</option></term> |
| <term><option>--stop-exec-queue</option></term> |
| <listitem> |
| <para>Signal systemd-udevd to stop executing new events. Incoming events |
| will be queued.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-S</option></term> |
| <term><option>--start-exec-queue</option></term> |
| <listitem> |
| <para>Signal systemd-udevd to enable the execution of events.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-R</option></term> |
| <term><option>--reload</option></term> |
| <listitem> |
| <para>Signal systemd-udevd to reload the rules files and other databases like the kernel |
| module index. Reloading rules and databases does not apply any changes to already |
| existing devices; the new configuration will only be applied to new events.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-p</option></term> |
| <term><option>--property=<replaceable>KEY</replaceable>=<replaceable>value</replaceable></option></term> |
| <listitem> |
| <para>Set a global property for all events.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-m</option></term> |
| <term><option>--children-max=</option><replaceable>value</replaceable></term> |
| <listitem> |
| <para>Set the maximum number of events, systemd-udevd will handle at the |
| same time.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>--ping</option></term> |
| <listitem> |
| <para>Send a ping message to systemd-udevd and wait for the reply. This may be useful to check that |
| systemd-udevd daemon is running.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-t</option></term> |
| <term><option>--timeout=</option><replaceable>seconds</replaceable></term> |
| <listitem> |
| <para>The maximum number of seconds to wait for a reply from systemd-udevd.</para> |
| </listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| </variablelist> |
| </refsect2> |
| |
| <refsect2><title>udevadm monitor |
| <arg choice="opt"><replaceable>options</replaceable></arg> |
| </title> |
| <para>Listens to the kernel uevents and events sent out by a udev rule |
| and prints the devpath of the event to the console. It can be used to analyze the |
| event timing, by comparing the timestamps of the kernel uevent and the udev event. |
| </para> |
| <variablelist> |
| <varlistentry> |
| <term><option>-k</option></term> |
| <term><option>--kernel</option></term> |
| <listitem> |
| <para>Print the kernel uevents.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-u</option></term> |
| <term><option>--udev</option></term> |
| <listitem> |
| <para>Print the udev event after the rule processing.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-p</option></term> |
| <term><option>--property</option></term> |
| <listitem> |
| <para>Also print the properties of the event.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-s</option></term> |
| <term><option>--subsystem-match=<replaceable>string[/string]</replaceable></option></term> |
| <listitem> |
| <para>Filter kernel uevents and udev events by subsystem[/devtype]. Only events with a matching subsystem value will pass. |
| When this option is specified more than once, then each matching result is ORed, that is, all devices in the specified |
| subsystems are monitored.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-t</option></term> |
| <term><option>--tag-match=<replaceable>string</replaceable></option></term> |
| <listitem> |
| <para>Filter udev events by tag. Only udev events with a given tag attached will pass. |
| When this option is specified more than once, then each matching result is ORed, that is, devices which have one of the |
| specified tags are monitored.</para> |
| </listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| </variablelist> |
| </refsect2> |
| |
| <refsect2><title>udevadm test |
| <arg choice="opt"><replaceable>options</replaceable></arg> |
| <arg choice="opt"><replaceable>devpath</replaceable>|<replaceable>file</replaceable>|<replaceable>unit</replaceable></arg> |
| </title> |
| <para>Simulate a udev event run for the given device, and print debug output.</para> |
| <variablelist> |
| <varlistentry> |
| <term><option>-a</option></term> |
| <term><option>--action=<replaceable>ACTION</replaceable></option></term> |
| <listitem> |
| <para>Type of event to be simulated. Possible actions are <literal>add</literal>, |
| <literal>remove</literal>, <literal>change</literal>, <literal>move</literal>, |
| <literal>online</literal>, <literal>offline</literal>, <literal>bind</literal>, |
| and <literal>unbind</literal>. Also, the special value <literal>help</literal> can be used |
| to list the possible actions. The default value is <literal>add</literal>.</para> |
| </listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><option>-N</option></term> |
| <term><option>--resolve-names=<constant>early</constant>|<constant>late</constant>|<constant>never</constant></option></term> |
| <listitem> |
| <para>Specify when udevadm should resolve names of users |
| and groups. When set to <constant>early</constant> (the |
| default), names will be resolved when the rules are |
| parsed. When set to <constant>late</constant>, names will |
| be resolved for every event. When set to |
| <constant>never</constant>, names will never be resolved |
| and all devices will be owned by root.</para> |
| </listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| </variablelist> |
| </refsect2> |
| |
| <refsect2><title>udevadm test-builtin |
| <arg choice="opt"><replaceable>options</replaceable></arg> |
| <arg><replaceable>command</replaceable></arg> |
| <arg choice="opt"><replaceable>devpath</replaceable>|<replaceable>file</replaceable>|<replaceable>unit</replaceable></arg> |
| </title> |
| <para>Run a built-in command <replaceable>COMMAND</replaceable> |
| for device <replaceable>DEVPATH</replaceable>, and print debug |
| output.</para> |
| <variablelist> |
| <varlistentry> |
| <term><option>-a</option></term> |
| <term><option>--action=<replaceable>ACTION</replaceable></option></term> |
| <listitem> |
| <para>Type of event to be simulated. Possible actions are <literal>add</literal>, |
| <literal>remove</literal>, <literal>change</literal>, <literal>move</literal>, |
| <literal>online</literal>, <literal>offline</literal>, <literal>bind</literal>, |
| and <literal>unbind</literal>. Also, the special value <literal>help</literal> can be used |
| to list the possible actions. The default value is <literal>add</literal>.</para> |
| </listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| </variablelist> |
| </refsect2> |
| |
| <refsect2> |
| <title>udevadm wait |
| <arg choice="opt"><replaceable>options</replaceable></arg> |
| <arg choice="opt"><replaceable>device|syspath</replaceable></arg> |
| … |
| </title> |
| |
| <para>Wait for devices or device symlinks being created and initialized by |
| <command>systemd-udevd</command>. Each device path must start with |
| <literal>/dev/</literal> or <literal>/sys/</literal>, e.g. <literal>/dev/sda</literal>, |
| <literal>/dev/disk/by-path/pci-0000:3c:00.0-nvme-1-part1</literal>, |
| <literal>/sys/devices/pci0000:00/0000:00:1f.6/net/eth0</literal>, or |
| <literal>/sys/class/net/eth0</literal>. This can take multiple devices. This may be useful for |
| waiting for devices being processed by <command>systemd-udevd</command> after e.g. partitioning |
| or formatting the devices.</para> |
| |
| <variablelist> |
| <varlistentry> |
| <term><option>-t</option></term> |
| <term><option>--timeout=<replaceable>SECONDS</replaceable></option></term> |
| <listitem> |
| <para>Maximum number of seconds to wait for the specified devices or device symlinks being |
| created, initialized, or removed. The default value is <literal>infinity</literal>.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--initialized=<replaceable>BOOL</replaceable></option></term> |
| <listitem> |
| <para>Check if <command>systemd-udevd</command> initialized devices. Defaults to true. When |
| false, the command only checks if the specified devices exist. Set false to this setting if |
| there is no udev rules for the specified devices, as the devices will never be considered |
| as initialized in that case. See Initialized Devices section below for more details.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--removed</option></term> |
| <listitem> |
| <para>When specified, the command wait for devices being removed instead of created or |
| initialized. If this is specified, <option>--initialized=</option> will be ignored.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--settle</option></term> |
| <listitem> |
| <para>When specified, also watches the udev event queue, and wait for all queued events |
| being processed by <command>systemd-udevd</command>.</para> |
| </listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| </variablelist> |
| </refsect2> |
| |
| <refsect2> |
| <title>udevadm lock |
| <arg choice="opt"><replaceable>options</replaceable></arg> |
| <arg choice="opt"><replaceable>command</replaceable></arg> |
| … |
| </title> |
| |
| <para><command>udevadm lock</command> takes an (advisory) exclusive lock on a block device (or all |
| specified devices), as per <ulink url="https://systemd.io/BLOCK_DEVICE_LOCKING">Locking Block Device |
| Access</ulink> and invokes a program with the locks taken. When the invoked program exits the locks |
| are automatically released and its return value is propagated as exit code of <command>udevadm |
| lock</command>.</para> |
| |
| <para>This tool is in particular useful to ensure that |
| <citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| does not probe a block device while changes are made to it, for example partitions created or file |
| systems formatted. Note that many tools that interface with block devices natively support taking |
| relevant locks, see for example |
| <citerefentry project='man-pages'><refentrytitle>sfdisk</refentrytitle><manvolnum>8</manvolnum></citerefentry>'s |
| <option>--lock</option> switch.</para> |
| |
| <para>The command expects at least one block device specified via <option>--device=</option> or |
| <option>--backing=</option>, and a command line to execute as arguments.</para> |
| |
| <variablelist> |
| <varlistentry> |
| <term><option>--device=<replaceable>DEVICE</replaceable></option></term> |
| <term><option>-d <replaceable>DEVICE</replaceable></option></term> |
| |
| <listitem><para>Takes a path to a device node of the device to lock. This switch may be used |
| multiple times (and in combination with <option>--backing=</option>) in order to lock multiple |
| devices. If a partition block device node is specified the containing "whole" block device is |
| automatically determined and used for the lock, as per the specification. If multiple devices are |
| specified, they are deduplicated, sorted by the major/minor of their device nodes and then locked |
| in order.</para> |
| |
| <para>This switch must be used at least once, to specify at least one device to |
| lock. (Alternatively, use <option>--backing=</option>, see below.)</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--backing=<replaceable>PATH</replaceable></option></term> |
| <term><option>-b <replaceable>PATH</replaceable></option></term> |
| |
| <listitem><para>If a path to a device node is specified, identical to |
| <option>--device=</option>. However, this switch alternatively accepts a path to a regular file or |
| directory, in which case the block device of the file system the file/directory resides on is |
| automatically determined and used as if it was specified with |
| <option>--device=</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--timeout=<replaceable>SECS</replaceable></option></term> |
| <term><option>-t <replaceable>SECS</replaceable></option></term> |
| |
| <listitem><para>Specifies how long to wait at most until all locks can be taken. Takes a value in |
| seconds, or in the usual supported time units, see |
| <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>. If |
| specified as zero the lock is attempted and if not successful the invocation will immediately |
| fail. If passed as <literal>infinity</literal> (the default) the invocation will wait indefinitely |
| until the lock can be acquired. If the lock cannot be taken in the specified time the specified |
| command will not be executed and the invocation will fail.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><option>--print</option></term> |
| <term><option>-p</option></term> |
| |
| <listitem><para>Instead of locking the specified devices and executing a command, just print the |
| device paths that would be locked, and execute no command. This command is useful to determine |
| the "whole" block device in case a partition block device is specified. The devices will be sorted |
| by their device node major number as primary ordering key and the minor number as secondary |
| ordering key (i.e. they are shown in the order they'd be locked). Note that the number of lines |
| printed here can be less than the number of <option>--device=</option> and |
| <option>--backing=</option> switches specified in case these resolve to the same "whole" |
| devices.</para></listitem> |
| </varlistentry> |
| |
| <xi:include href="standard-options.xml" xpointer="help" /> |
| </variablelist> |
| </refsect2> |
| </refsect1> |
| |
| <refsect1> |
| <title>Initialized Devices</title> |
| |
| <para>Initialized devices are those for which at least one udev rule already completed execution |
| – for any action but <literal>remove</literal> — that set a property or other device setting (and |
| thus has an entry in the udev device database). Devices are no longer considered initialized if a |
| <literal>remove</literal> action is seen for them (which removes their entry in the udev device |
| database). Note that devices that have no udev rules are never considered initialized, but might |
| still be announced via the sd-device API (or similar).</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Example</title> |
| |
| <example> |
| <title>Format a File System</title> |
| |
| <para>Take a lock on the backing block device while creating a file system, to ensure that |
| <command>systemd-udevd</command> doesn't probe or announce the new superblock before it is |
| comprehensively written:</para> |
| |
| <programlisting># udevadm lock --device=/dev/sda1 mkfs.ext4 /dev/sda1</programlisting> |
| </example> |
| |
| <example> |
| <title>Format a RAID File System</title> |
| |
| <para>Similar, but take locks on multiple devices at once:</para> |
| |
| <programlisting># udevadm lock --device=/dev/sda1 --device=/dev/sdb1 mkfs.btrfs /dev/sda1 /dev/sdb1</programlisting> |
| </example> |
| |
| <example> |
| <title>Copy in a File System</title> |
| |
| <para>Take a lock on the backing block device while copying in a prepared file system image, to ensure |
| that <command>systemd-udevd</command> doesn't probe or announce the new superblock before it is fully |
| written:</para> |
| |
| <programlisting># udevadm lock -d /dev/sda1 dd if=fs.raw of=/dev/sda1</programlisting> |
| </example> |
| </refsect1> |
| |
| <refsect1> |
| <title>See Also</title> |
| <para><citerefentry> |
| <refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum> |
| </citerefentry>, |
| <citerefentry> |
| <refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum> |
| </citerefentry></para> |
| </refsect1> |
| </refentry> |
