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diff --git a/man/udev.xml b/man/udev.xml deleted file mode 100644 index 3359fb0865..0000000000 --- a/man/udev.xml +++ /dev/null @@ -1,755 +0,0 @@ -<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> -<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" - "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> - -<refentry id="udev"> - <refentryinfo> - <title>udev</title> - <productname>systemd</productname> - <authorgroup> - <author> - <contrib>Developer</contrib> - <firstname>Greg</firstname> - <surname>Kroah-Hartmann</surname> - <email>greg@kroah.com</email> - </author> - <author> - <contrib>Developer</contrib> - <firstname>Kay</firstname> - <surname>Sievers</surname> - <email>kay@vrfy.org</email> - </author> - </authorgroup> - </refentryinfo> - - <refmeta> - <refentrytitle>udev</refentrytitle> - <manvolnum>7</manvolnum> - </refmeta> - - <refnamediv> - <refname>udev</refname> - <refpurpose>Dynamic device management</refpurpose> - </refnamediv> - - <refsect1><title>Description</title> - <para>udev supplies the system software with device events, manages permissions - of device nodes and may create additional symlinks in the <filename>/dev</filename> - directory, or renames network interfaces. The kernel usually just assigns unpredictable - device names based on the order of discovery. Meaningful symlinks or network device - names provide a way to reliably identify devices based on their properties or - current configuration.</para> - - <para>The udev daemon, <citerefentry><refentrytitle>systemd-udevd.service</refentrytitle> - <manvolnum>8</manvolnum></citerefentry>, receives device uevents directly from - the kernel whenever a device is added or removed from the system, or it changes its - state. When udev receives a device event, it matches its configured set of rules - against various device attributes to identify the device. Rules that match may - provide additional device information to be stored in the udev database or - to be used to create meaningful symlink names.</para> - - <para>All device information udev processes is stored in the udev database and - sent out to possible event subscribers. Access to all stored data and the event - sources is provided by the library libudev.</para> - </refsect1> - - <refsect1><title>Rules Files</title> - <para>The udev rules are read from the files located in the - system rules directory <filename>/usr/lib/udev/rules.d</filename>, - the volatile runtime directory <filename>/run/udev/rules.d</filename> - and the local administration directory <filename>/etc/udev/rules.d</filename>. - All rules files are collectively sorted and processed in lexical order, - regardless of the directories in which they live. However, files with - identical filenames replace each other. Files in <filename>/etc</filename> - have the highest priority, files in <filename>/run</filename> take precedence - over files with the same name in <filename>/usr/lib</filename>. This can be - used to override a system-supplied rules file with a local file if needed; - a symlink in <filename>/etc</filename> with the same name as a rules file in - <filename>/usr/lib</filename>, pointing to <filename>/dev/null</filename>, - disables the rules file entirely. Rule files must have the extension - <filename>.rules</filename>; other extensions are ignored.</para> - - <para>Every line in the rules file contains at least one key-value pair. - Except for empty lines or lines beginning with <literal>#</literal>, which are ignored. - There are two kinds of keys: match and assignment. - If all match keys match against their values, the rule gets applied and the - assignment keys get the specified values assigned.</para> - - <para>A matching rule may rename a network interface, add symlinks - pointing to the device node, or run a specified program as part of - the event handling.</para> - - <para>A rule consists of a comma-separated list of one or more key-value pairs. - Each key has a distinct operation, depending on the used operator. Valid - operators are:</para> - <variablelist> - <varlistentry> - <term><literal>==</literal></term> - <listitem> - <para>Compare for equality.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><literal>!=</literal></term> - <listitem> - <para>Compare for inequality.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><literal>=</literal></term> - <listitem> - <para>Assign a value to a key. Keys that represent a list are reset - and only this single value is assigned.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><literal>+=</literal></term> - <listitem> - <para>Add the value to a key that holds a list of entries.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><literal>-=</literal></term> - <listitem> - <para>Remove the value from a key that holds a list of entries.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><literal>:=</literal></term> - <listitem> - <para>Assign a value to a key finally; disallow any later changes.</para> - </listitem> - </varlistentry> - </variablelist> - - <para>The following key names can be used to match against device properties. - Some of the keys also match against properties of the parent devices in sysfs, - not only the device that has generated the event. If multiple keys that match - a parent device are specified in a single rule, all these keys must match at - one and the same parent device.</para> - <variablelist class='udev-directives'> - <varlistentry> - <term><varname>ACTION</varname></term> - <listitem> - <para>Match the name of the event action.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>DEVPATH</varname></term> - <listitem> - <para>Match the devpath of the event device.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>KERNEL</varname></term> - <listitem> - <para>Match the name of the event device.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>NAME</varname></term> - <listitem> - <para>Match the name of a network interface. It can be used once the - NAME key has been set in one of the preceding rules.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>SYMLINK</varname></term> - <listitem> - <para>Match the name of a symlink targeting the node. It can - be used once a SYMLINK key has been set in one of the preceding - rules. There may be multiple symlinks; only one needs to match. - </para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>SUBSYSTEM</varname></term> - <listitem> - <para>Match the subsystem of the event device.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><varname>DRIVER</varname></term> - <listitem> - <para>Match the driver name of the event device. Only set this key for devices - which are bound to a driver at the time the event is generated.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><varname>ATTR{<replaceable>filename</replaceable>}</varname></term> - <listitem> - <para>Match sysfs attribute values of the event device. Trailing - whitespace in the attribute values is ignored unless the specified match - value itself contains trailing whitespace. - </para> - </listitem> - <term><varname>SYSCTL{<replaceable>kernel parameter</replaceable>}</varname></term> - <listitem> - <para>Match a kernel parameter value. - </para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>KERNELS</varname></term> - <listitem> - <para>Search the devpath upwards for a matching device name.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>SUBSYSTEMS</varname></term> - <listitem> - <para>Search the devpath upwards for a matching device subsystem name.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>DRIVERS</varname></term> - <listitem> - <para>Search the devpath upwards for a matching device driver name.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>ATTRS{<replaceable>filename</replaceable>}</varname></term> - <listitem> - <para>Search the devpath upwards for a device with matching sysfs attribute values. - If multiple <varname>ATTRS</varname> matches are specified, all of them - must match on the same device. Trailing whitespace in the attribute values is ignored - unless the specified match value itself contains trailing whitespace.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>TAGS</varname></term> - <listitem> - <para>Search the devpath upwards for a device with matching tag.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>ENV{<replaceable>key</replaceable>}</varname></term> - <listitem> - <para>Match against a device property value.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>TAG</varname></term> - <listitem> - <para>Match against a device tag.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>TEST{<replaceable>octal mode mask</replaceable>}</varname></term> - <listitem> - <para>Test the existence of a file. An octal mode mask can be specified - if needed.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>PROGRAM</varname></term> - <listitem> - <para>Execute a program to determine whether there - is a match; the key is true if the program returns - successfully. The device properties are made available to the - executed program in the environment. The program's standard output - is available in the <varname>RESULT</varname> key.</para> - <para>This can only be used for very short-running foreground tasks. For details, - see <varname>RUN</varname>.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>RESULT</varname></term> - <listitem> - <para>Match the returned string of the last <varname>PROGRAM</varname> call. - This key can be used in the same or in any later rule after a - <varname>PROGRAM</varname> call.</para> - </listitem> - </varlistentry> - </variablelist> - - <para>Most of the fields support shell glob pattern matching and - alternate patterns. The following special characters are supported:</para> - <variablelist> - <varlistentry> - <term><literal>*</literal></term> - <listitem> - <para>Matches zero or more characters.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><literal>?</literal></term> - <listitem> - <para>Matches any single character.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><literal>[]</literal></term> - <listitem> - <para>Matches any single character specified within the brackets. For - example, the pattern string <literal>tty[SR]</literal> - would match either <literal>ttyS</literal> or <literal>ttyR</literal>. - Ranges are also supported via the <literal>-</literal> character. - For example, to match on the range of all digits, the pattern - <literal>[0-9]</literal> could be used. If the first character - following the <literal>[</literal> is a <literal>!</literal>, - any characters not enclosed are matched.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><literal>|</literal></term> - <listitem> - <para>Separates alternative patterns. For example, the pattern string - <literal>abc|x*</literal> would match either <literal>abc</literal> - or <literal>x*</literal>.</para> - </listitem> - </varlistentry> - </variablelist> - - <para>The following keys can get values assigned:</para> - <variablelist class='udev-directives'> - <varlistentry> - <term><varname>NAME</varname></term> - <listitem> - <para>The name to use for a network interface. See - <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry> - for a higher-level mechanism for setting the interface name. - The name of a device node cannot be changed by udev, only additional - symlinks can be created.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>SYMLINK</varname></term> - <listitem> - <para>The name of a symlink targeting the node. Every matching rule adds - this value to the list of symlinks to be created.</para> - <para>The set of characters to name a symlink is limited. Allowed - characters are <literal>0-9A-Za-z#+-.:=@_/</literal>, valid UTF-8 character - sequences, and <literal>\x00</literal> hex encoding. All other - characters are replaced by a <literal>_</literal> character.</para> - <para>Multiple symlinks may be specified by separating the names by the - space character. In case multiple devices claim the same name, the link - always points to the device with the highest link_priority. If the current - device goes away, the links are re-evaluated and the device with the - next highest link_priority becomes the owner of the link. If no - link_priority is specified, the order of the devices (and which one of - them owns the link) is undefined.</para> - <para>Symlink names must never conflict with the kernel's default device - node names, as that would result in unpredictable behavior. - </para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>OWNER</varname>, <varname>GROUP</varname>, <varname>MODE</varname></term> - <listitem> - <para>The permissions for the device node. Every specified value overrides - the compiled-in default value.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>SECLABEL{<replaceable>module</replaceable>}</varname></term> - <listitem> - <para>Applies the specified Linux Security Module label to the device node.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>ATTR{<replaceable>key</replaceable>}</varname></term> - <listitem> - <para>The value that should be written to a sysfs attribute of the - event device.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>SYSCTL{<replaceable>kernel parameter</replaceable>}</varname></term> - <listitem> - <para>The value that should be written to kernel parameter.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>ENV{<replaceable>key</replaceable>}</varname></term> - <listitem> - <para>Set a device property value. Property names with a leading <literal>.</literal> - are neither stored in the database nor exported to events or - external tools (run by, for example, the <varname>PROGRAM</varname> - match key).</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>TAG</varname></term> - <listitem> - <para>Attach a tag to a device. This is used to filter events for users - of libudev's monitor functionality, or to enumerate a group of tagged - devices. The implementation can only work efficiently if only a few - tags are attached to a device. It is only meant to be used in - contexts with specific device filter requirements, and not as a - general-purpose flag. Excessive use might result in inefficient event - handling.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>RUN{<replaceable>type</replaceable>}</varname></term> - <listitem> - <para>Add a program to the list of programs to be executed after - processing all the rules for a specific event, depending on - <literal>type</literal>:</para> - <variablelist> - <varlistentry> - <term><literal>program</literal></term> - <listitem> - <para>Execute an external program specified as the assigned - value. If no absolute path is given, the program is expected - to live in <filename>/usr/lib/udev</filename>; otherwise, the - absolute path must be specified.</para> - <para>This is the default if no <replaceable>type</replaceable> - is specified.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><literal>builtin</literal></term> - <listitem> - <para>As <varname>program</varname>, but use one of the - built-in programs rather than an external one.</para> - </listitem> - </varlistentry> - </variablelist> - <para>The program name and following arguments are separated by spaces. - Single quotes can be used to specify arguments with spaces.</para> - <para>This can only be used for very short-running foreground tasks. Running an - event process for a long period of time may block all further events for - this or a dependent device.</para> - <para>Starting daemons or other long-running processes is not appropriate - for udev; the forked processes, detached or not, will be unconditionally - killed after the event handling has finished.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>LABEL</varname></term> - <listitem> - <para>A named label to which a <varname>GOTO</varname> may jump.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>GOTO</varname></term> - <listitem> - <para>Jumps to the next <varname>LABEL</varname> with a matching name.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>IMPORT{<replaceable>type</replaceable>}</varname></term> - <listitem> - <para>Import a set of variables as device properties, - depending on <literal>type</literal>:</para> - <variablelist> - <varlistentry> - <term><literal>program</literal></term> - <listitem> - <para>Execute an external program specified as the assigned - value and, if it returns successfully, - import its output, which must be in environment key - format. Path specification, command/argument separation, - and quoting work like in <varname>RUN</varname>.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><literal>builtin</literal></term> - <listitem> - <para>Similar to <literal>program</literal>, but use one of the - built-in programs rather than an external one.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><literal>file</literal></term> - <listitem> - <para>Import a text file specified as the assigned value, the content - of which must be in environment key format.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><literal>db</literal></term> - <listitem> - <para>Import a single property specified as the assigned value from the - current device database. This works only if the database is already populated - by an earlier event.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><literal>cmdline</literal></term> - <listitem> - <para>Import a single property from the kernel command line. For simple flags - the value of the property is set to <literal>1</literal>.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><literal>parent</literal></term> - <listitem> - <para>Import the stored keys from the parent device by reading - the database entry of the parent device. The value assigned to - <option>IMPORT{parent}</option> is used as a filter of key names - to import (with the same shell glob pattern matching used for - comparisons).</para> - </listitem> - </varlistentry> - </variablelist> - <para>This can only be used for very short-running foreground tasks. For details - see <option>RUN</option>.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><varname>OPTIONS</varname></term> - <listitem> - <para>Rule and device options:</para> - <variablelist class='udev-directives'> - <varlistentry> - <term><option>link_priority=<replaceable>value</replaceable></option></term> - <listitem> - <para>Specify the priority of the created symlinks. Devices with higher - priorities overwrite existing symlinks of other devices. The default is 0.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><option>string_escape=<replaceable>none|replace</replaceable></option></term> - <listitem> - <para>Usually, control and other possibly unsafe characters are replaced - in strings used for device naming. The mode of replacement can be specified - with this option.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><option>static_node=</option></term> - <listitem> - <para>Apply the permissions specified in this rule to the - static device node with the specified name. Also, for every - tag specified in this rule, create a symlink - in the directory - <filename>/run/udev/static_node-tags/<replaceable>tag</replaceable></filename> - pointing at the static device node with the specified name. - Static device node creation is performed by systemd-tmpfiles - before systemd-udevd is started. The static nodes might not - have a corresponding kernel device; they are used to trigger - automatic kernel module loading when they are accessed.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><option>watch</option></term> - <listitem> - <para>Watch the device node with inotify; when the node is - closed after being opened for writing, a change uevent is - synthesized.</para> - </listitem> - </varlistentry> - <varlistentry> - <term><option>nowatch</option></term> - <listitem> - <para>Disable the watching of a device node with inotify.</para> - </listitem> - </varlistentry> - </variablelist> - </listitem> - </varlistentry> - </variablelist> - - <para>The <varname>NAME</varname>, <varname>SYMLINK</varname>, - <varname>PROGRAM</varname>, <varname>OWNER</varname>, - <varname>GROUP</varname>, <varname>MODE</varname>, <varname>SECLABEL</varname>, - and <varname>RUN</varname> fields support simple string substitutions. - The <varname>RUN</varname> substitutions are performed after all rules - have been processed, right before the program is executed, allowing for - the use of device properties set by earlier matching rules. For all other - fields, substitutions are performed while the individual rule is being - processed. The available substitutions are:</para> - <variablelist class='udev-directives'> - <varlistentry> - <term><option>$kernel</option>, <option>%k</option></term> - <listitem> - <para>The kernel name for this device.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$number</option>, <option>%n</option></term> - <listitem> - <para>The kernel number for this device. For example, - <literal>sda3</literal> has kernel number <literal>3</literal>. - </para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$devpath</option>, <option>%p</option></term> - <listitem> - <para>The devpath of the device.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$id</option>, <option>%b</option></term> - <listitem> - <para>The name of the device matched while searching the devpath - upwards for <option>SUBSYSTEMS</option>, <option>KERNELS</option>, - <option>DRIVERS</option>, and <option>ATTRS</option>. - </para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$driver</option></term> - <listitem> - <para>The driver name of the device matched while searching the - devpath upwards for <option>SUBSYSTEMS</option>, - <option>KERNELS</option>, <option>DRIVERS</option>, and - <option>ATTRS</option>. - </para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$attr{<replaceable>file</replaceable>}</option>, <option>%s{<replaceable>file</replaceable>}</option></term> - <listitem> - <para>The value of a sysfs attribute found at the device where - all keys of the rule have matched. If the matching device does not - have such an attribute, and a previous <option>KERNELS</option>, - <option>SUBSYSTEMS</option>, <option>DRIVERS</option>, or - <option>ATTRS</option> test selected a parent device, then the - attribute from that parent device is used. - </para> - <para>If the attribute is a symlink, the last element of the - symlink target is returned as the value. - </para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$env{<replaceable>key</replaceable>}</option>, <option>%E{<replaceable>key</replaceable>}</option></term> - <listitem> - <para>A device property value.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$major</option>, <option>%M</option></term> - <listitem> - <para>The kernel major number for the device.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$minor</option>, <option>%m</option></term> - <listitem> - <para>The kernel minor number for the device.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$result</option>, <option>%c</option></term> - <listitem> - <para>The string returned by the external program requested with - <varname>PROGRAM</varname>. - A single part of the string, separated by a space character, may be selected - by specifying the part number as an attribute: <literal>%c{N}</literal>. - If the number is followed by the <literal>+</literal> character, this part plus all remaining parts - of the result string are substituted: <literal>%c{N+}</literal>.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$parent</option>, <option>%P</option></term> - <listitem> - <para>The node name of the parent device.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$name</option></term> - <listitem> - <para>The current name of the device. If not changed by a rule, it is the - name of the kernel device.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$links</option></term> - <listitem> - <para>A space-separated list of the current symlinks. The value is - only set during a remove event or if an earlier rule assigned a value.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$root</option>, <option>%r</option></term> - <listitem> - <para>The udev_root value.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$sys</option>, <option>%S</option></term> - <listitem> - <para>The sysfs mount point.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$devnode</option>, <option>%N</option></term> - <listitem> - <para>The name of the device node.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>%%</option></term> - <listitem> - <para>The <literal>%</literal> character itself.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$$</option></term> - <listitem> - <para>The <literal>$</literal> character itself.</para> - </listitem> - </varlistentry> - </variablelist> - </refsect1> - - <refsect1> - <title>See Also</title> - <para> - <citerefentry> - <refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum> - </citerefentry>, - <citerefentry> - <refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum> - </citerefentry>, - <citerefentry> - <refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum> - </citerefentry> - </para> - </refsect1> -</refentry> |