mirror of
https://github.com/AuxXxilium/eudev.git
synced 2024-11-24 07:20:56 +07:00
700 lines
29 KiB
XML
700 lines
29 KiB
XML
<?xml version='1.0'?>
|
|
<?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
|
|
<!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>udev</productname>
|
|
</refentryinfo>
|
|
|
|
<refmeta>
|
|
<refentrytitle>udev</refentrytitle>
|
|
<manvolnum>7</manvolnum>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>udev</refname>
|
|
<refpurpose>Linux 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>udevd</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>Configuration</title>
|
|
<para>udev configuration files are placed in <filename>/etc/udev/</filename>
|
|
and <filename>/lib/udev/</filename>. All empty lines or lines beginning with
|
|
'#' are ignored.</para>
|
|
|
|
<refsect2><title>Configuration file</title>
|
|
<para>udev expects its main configuration file at <filename>/etc/udev/udev.conf</filename>.
|
|
It consists of a set of variables allowing the user to override default udev values.
|
|
The following variables can be set:</para>
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><option>udev_root</option></term>
|
|
<listitem>
|
|
<para>Specifies where to place the device nodes in the filesystem.
|
|
The default value is <filename>/dev</filename>.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>udev_log</option></term>
|
|
<listitem>
|
|
<para>The logging priority. Valid values are the numerical syslog priorities
|
|
or their textual representations: <option>err</option>, <option>info</option>
|
|
and <option>debug</option>.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect2>
|
|
|
|
<refsect2><title>Rules files</title>
|
|
<para>The udev rules are read from the files located in the
|
|
default rules directory <filename>/lib/udev/rules.d/</filename>,
|
|
the custom rules directory <filename>/etc/udev/rules.d/</filename>
|
|
and the temporary rules directory <filename>/run/udev/rules.d/</filename>.
|
|
All rule files are collectively sorted and processed in lexical order,
|
|
regardless of the directories in which they live. However, files in
|
|
<filename>/etc/udev/rules.d/</filename> take precedence over files with
|
|
the same name in <filename>/lib/udev/rules.d/</filename>; this can be
|
|
used to ignore a default rules file if needed.</para>
|
|
|
|
<para>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.
|
|
There are two kind of keys: match and assignment.
|
|
If all match keys are matching against its value, the rule gets applied and the
|
|
assignment keys get the specified value 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><option>==</option></term>
|
|
<listitem>
|
|
<para>Compare for equality.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>!=</option></term>
|
|
<listitem>
|
|
<para>Compare for inequality.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>=</option></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><option>+=</option></term>
|
|
<listitem>
|
|
<para>Add the value to a key that holds a list of entries.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>:=</option></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>
|
|
<varlistentry>
|
|
<term><option>ACTION</option></term>
|
|
<listitem>
|
|
<para>Match the name of the event action.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>DEVPATH</option></term>
|
|
<listitem>
|
|
<para>Match the devpath of the event device.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>KERNEL</option></term>
|
|
<listitem>
|
|
<para>Match the name of the event device.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>NAME</option></term>
|
|
<listitem>
|
|
<para>Match the name of the node or network interface. It can
|
|
be used once the NAME key has been set in one of the preceding
|
|
rules.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>SYMLINK</option></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><option>SUBSYSTEM</option></term>
|
|
<listitem>
|
|
<para>Match the subsystem of the event device.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><option>DRIVER</option></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><option>ATTR{<replaceable>filename</replaceable>}</option></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>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>KERNELS</option></term>
|
|
<listitem>
|
|
<para>Search the devpath upwards for a matching device name.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>SUBSYSTEMS</option></term>
|
|
<listitem>
|
|
<para>Search the devpath upwards for a matching device subsystem name.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>DRIVERS</option></term>
|
|
<listitem>
|
|
<para>Search the devpath upwards for a matching device driver name.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>ATTRS{<replaceable>filename</replaceable>}</option></term>
|
|
<listitem>
|
|
<para>Search the devpath upwards for a device with matching sysfs attribute values.
|
|
If multiple <option>ATTRS</option> 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><option>ENV{<replaceable>key</replaceable>}</option></term>
|
|
<listitem>
|
|
<para>Match against a device property value.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>TAG</option></term>
|
|
<listitem>
|
|
<para>Match against a device tag.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>TEST{<replaceable>octal mode mask</replaceable>}</option></term>
|
|
<listitem>
|
|
<para>Test the existence of a file. An octal mode mask can be specified
|
|
if needed.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>PROGRAM</option></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 stdout
|
|
is available in the RESULT key.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>RESULT</option></term>
|
|
<listitem>
|
|
<para>Match the returned string of the last PROGRAM call. This key can
|
|
be used in the same or in any later rule after a PROGRAM call.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
<para>Most of the fields support shell-style pattern matching. The following
|
|
pattern characters are supported:</para>
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><option>*</option></term>
|
|
<listitem>
|
|
<para>Matches zero or more characters.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><option>?</option></term>
|
|
<listitem>
|
|
<para>Matches any single character.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><option>[]</option></term>
|
|
<listitem>
|
|
<para>Matches any single character specified within the brackets. For
|
|
example, the pattern string 'tty[SR]' would match either 'ttyS' or 'ttyR'.
|
|
Ranges are also supported via the '-' character.
|
|
For example, to match on the range of all digits, the pattern [0-9] could
|
|
be used. If the first character following the '[' is a '!', any characters
|
|
not enclosed are matched.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
|
|
<para>The following keys can get values assigned:</para>
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><option>NAME</option></term>
|
|
<listitem>
|
|
<para>What a network interface should be named.</para>
|
|
<para>Also, as a temporary workaround, this is what a device node
|
|
should be named; usually the kernel provides the defined node name or creates
|
|
and removes the node before udev even receives any event. Changing
|
|
the node name from the kernel's default creates inconsistencies
|
|
and is not supported. If the kernel and NAME specify different names,
|
|
an error is logged. udev is only expected to handle device node
|
|
permissions and to create additional symlinks, not to change
|
|
kernel-provided device node names. Instead of renaming a device node,
|
|
SYMLINK should be used. However, symlink names must never conflict with
|
|
device node names, as that would result in unpredictable behavior.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>SYMLINK</option></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. 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. Also, 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><option>OWNER, GROUP, MODE</option></term>
|
|
<listitem>
|
|
<para>The permissions for the device node. Every specified value overwrites
|
|
the compiled-in default value.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>ATTR{<replaceable>key</replaceable>}</option></term>
|
|
<listitem>
|
|
<para>The value that should be written to a sysfs attribute of the
|
|
event device.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>ENV{<replaceable>key</replaceable>}</option></term>
|
|
<listitem>
|
|
<para>Set a device property value. Property names with a leading '.'
|
|
are neither stored in the database nor exported to events or
|
|
external tools (run by, say, the PROGRAM match key).</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>TAG</option></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><option>RUN</option></term>
|
|
<listitem>
|
|
<para>Add a program to the list of programs to be executed for a specific
|
|
device. This can only be used for very short running tasks. Running an
|
|
event process for a long period of time may block all further events for
|
|
this or a dependent device. Long running tasks need to be immediately
|
|
detached from the event process itself.</para>
|
|
<para>If no absolute path is given, the program is expected to live in
|
|
the directory provided at compile-time to configure via --libexecdir
|
|
(this is usually <filename>/lib/udev</filename>), otherwise the absolute
|
|
path must be specified. The program name and following arguments are
|
|
separated by spaces. Single quotes can be used to specify arguments with
|
|
spaces.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>LABEL</option></term>
|
|
<listitem>
|
|
<para>A named label to which a GOTO may jump.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>GOTO</option></term>
|
|
<listitem>
|
|
<para>Jumps to the next LABEL with a matching name.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>IMPORT{<replaceable>type</replaceable>}</option></term>
|
|
<listitem>
|
|
<para>Import a set of variables as device properties,
|
|
depending on <replaceable>type</replaceable>:</para>
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><option>program</option></term>
|
|
<listitem>
|
|
<para>Execute an external program specified as the assigned value and
|
|
import its output, which must be in environment key
|
|
format. Path specification, command/argument separation,
|
|
and quoting work like in <option>RUN</option>.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><option>file</option></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><option>db</option></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><option>cmdline</option></term>
|
|
<listitem>
|
|
<para>Import a single property from the kernel command line. For simple flags
|
|
the value of the property is set to '1'.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><option>parent</option></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-style pattern matching used for
|
|
comparisons).</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
<para>If no option is given, udev chooses between <option>program</option>
|
|
and <option>file</option> based on the executable bit of the file
|
|
permissions.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>WAIT_FOR</option></term>
|
|
<listitem>
|
|
<para>Wait for a file to become available or until a timeout of
|
|
10 seconds expires. The path is relative to the sysfs device;
|
|
if no path is specified, this waits for an attribute to appear.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>OPTIONS</option></term>
|
|
<listitem>
|
|
<para>Rule and device options:</para>
|
|
<variablelist>
|
|
<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>event_timeout=</option></term>
|
|
<listitem>
|
|
<para>Number of seconds an event waits for operations to finish before
|
|
giving up and terminating itself.</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. Static device nodes might be provided by kernel modules
|
|
or copied from <filename>/lib/udev/devices</filename>. These nodes might not have
|
|
a corresponding kernel device at the time udevd is started; they can trigger
|
|
automatic kernel module loading.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><option>watch</option></term>
|
|
<listitem>
|
|
<para>Watch the device node with inotify; when closed after being opened for
|
|
writing, a change uevent is synthesised.</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 <option>NAME</option>, <option>SYMLINK</option>, <option>PROGRAM</option>,
|
|
<option>OWNER</option>, <option>GROUP</option>, <option>MODE</option> and <option>RUN</option>
|
|
fields support simple string substitutions. The <option>RUN</option>
|
|
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>
|
|
<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, 'sda3' has
|
|
kernel number of '3'</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 KERNELS, SUBSYSTEMS, DRIVERS, or
|
|
ATTRS 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 PROGRAM.
|
|
A single part of the string, separated by a space character, may be selected
|
|
by specifying the part number as an attribute: <option>%c{N}</option>.
|
|
If the number is followed by the '+' character, this part plus all remaining parts
|
|
of the result string are substituted: <option>%c{N+}</option></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 node. 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>$sys</option>, <option>%S</option></term>
|
|
<listitem>
|
|
<para>The sysfs mount point.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>$tempnode</option>, <option>%N</option></term>
|
|
<listitem>
|
|
<para>The name of a temporary device node created to provide access to
|
|
the device from a external program before the real node is created.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>%%</option></term>
|
|
<listitem>
|
|
<para>The '%' character itself.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>$$</option></term>
|
|
<listitem>
|
|
<para>The '$' character itself.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect2>
|
|
</refsect1>
|
|
|
|
<refsect1><title>Author</title>
|
|
<para>Written by Greg Kroah-Hartman <email>greg@kroah.com</email> and
|
|
Kay Sievers <email>kay.sievers@vrfy.org</email>. With much help from
|
|
Dan Stekloff and many others.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
<para><citerefentry>
|
|
<refentrytitle>udevd</refentrytitle><manvolnum>8</manvolnum>
|
|
</citerefentry>,
|
|
<citerefentry>
|
|
<refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum>
|
|
</citerefentry></para>
|
|
</refsect1>
|
|
</refentry>
|