diff options
Diffstat (limited to 'udev/udev.xml')
| -rw-r--r-- | udev/udev.xml | 1342 |
1 files changed, 669 insertions, 673 deletions
diff --git a/udev/udev.xml b/udev/udev.xml index 678023c373..adf531b372 100644 --- a/udev/udev.xml +++ b/udev/udev.xml @@ -1,677 +1,673 @@ <?xml version='1.0'?> -<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" +<?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"> -<article> - <section> +<refentry id="udev"> + <refentryinfo> <title>udev</title> - <refentry> - <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 information - 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 are 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 - '#' will be 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>/dev/.udev/rules.d/</filename>. - All rule files are sorted and processed in lexical order, regardless - in which of these directories they live.</para> - - <para>Rule files are required to have a unique name, duplicate file names - are ignored. Files in <filename>/etc/udev/rules.d/</filename> have 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>Every line in the rules file contains at least one key value pair. - There are two kind of keys, match and assignment keys. - If all match keys are matching against its value, the rule gets applied and the - assign 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 list of one or more key value pairs separated by - a comma. 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, - which may be used to prevent changes by any later rules.</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 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, if the specified match - value does not contain trailing whitespace itself. - </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, - if the specified match value does not contain trailing whitespace itself.</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. 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 output printed to - 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 a shell style pattern matching. The following - pattern characters are supported:</para> - <variablelist> - <varlistentry> - <term><option>*</option></term> - <listitem> - <para>Matches zero, or any number of 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 within this match with the '-' character. - For example, to match on the range of all digits, the pattern [0-9] would - 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>The name, a network interface should be renamed to. Or as - a temporary workaraound, the name a device node should be named. - Usually the kernel provides the defined node name, or even 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 will be 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. Symlink names must never conflict with - device node names, it will 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 will add - 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 will always point to the device with - the highest link_priority. If the current device goes away, the links will - be re-evaluated and the device with the next highest link_priority will own - the link. If no link_priority is specified, the order of the devices, and - which one of them will own the link, is undefined. Claiming the same name for - a symlink, which is or might be used for a device node, may result in - unexpected behavior and is not supported. - </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 not stored in the database or exported to external tool or events.</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. If the option - <option>RUN{<replaceable>fail_event_on_error</replaceable>}</option> is - specified, and the executed program returns non-zero, the event will be - marked as failed for a possible later handling.</para> - <para>If no absolute path is given, the program is expected to live in - <filename>/lib/udev</filename>, otherwise the absolute path must be - specified. Program name and 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>Named label where a GOTO can jump to.</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, 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>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 will choose 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 10 - seconds timeout expires.</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 will wait for operations to finish, before it - will terminate 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>watch</option></term> - <listitem> - <para>Watch the device node with inotify, when closed after being opened for - writing, a change uevent will be synthesised.</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 printf-like string substitutions. The <option>RUN</option> - format chars gets applied after all rules have been processed, right before the program - is executed. It allows the use of device properties set by earlier matching - rules. For all other fields, substitutions are applied 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, follow the chain of parent devices and use the value - of the first attribute that matches. - 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 '+' char 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>$links</option></term> - <listitem> - <para>The current list of symlinks, separated by a space character. The value is - only set if an earlier rule assigned a value, or during a remove events.</para> - </listitem> - </varlistentry> - - <varlistentry> - <term><option>$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 created temporary device node 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> - </section> -</article> + <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 information + 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 are 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 + '#' will be 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>/dev/.udev/rules.d/</filename>. + All rule files are sorted and processed in lexical order, regardless + in which of these directories they live.</para> + + <para>Rule files are required to have a unique name, duplicate file names + are ignored. Files in <filename>/etc/udev/rules.d/</filename> have 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>Every line in the rules file contains at least one key value pair. + There are two kind of keys, match and assignment keys. + If all match keys are matching against its value, the rule gets applied and the + assign 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 list of one or more key value pairs separated by + a comma. 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, + which may be used to prevent changes by any later rules.</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 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, if the specified match + value does not contain trailing whitespace itself. + </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, + if the specified match value does not contain trailing whitespace itself.</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. 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 output printed to + 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 a shell style pattern matching. The following + pattern characters are supported:</para> + <variablelist> + <varlistentry> + <term><option>*</option></term> + <listitem> + <para>Matches zero, or any number of 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 within this match with the '-' character. + For example, to match on the range of all digits, the pattern [0-9] would + 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>The name, a network interface should be renamed to. Or as + a temporary workaraound, the name a device node should be named. + Usually the kernel provides the defined node name, or even 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 will be 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. Symlink names must never conflict with + device node names, it will 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 will add + 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 will always point to the device with + the highest link_priority. If the current device goes away, the links will + be re-evaluated and the device with the next highest link_priority will own + the link. If no link_priority is specified, the order of the devices, and + which one of them will own the link, is undefined. Claiming the same name for + a symlink, which is or might be used for a device node, may result in + unexpected behavior and is not supported. + </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 not stored in the database or exported to external tool or events.</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. If the option + <option>RUN{<replaceable>fail_event_on_error</replaceable>}</option> is + specified, and the executed program returns non-zero, the event will be + marked as failed for a possible later handling.</para> + <para>If no absolute path is given, the program is expected to live in + <filename>/lib/udev</filename>, otherwise the absolute path must be + specified. Program name and 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>Named label where a GOTO can jump to.</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, 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>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 will choose 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 10 + seconds timeout expires.</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 will wait for operations to finish, before it + will terminate 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>watch</option></term> + <listitem> + <para>Watch the device node with inotify, when closed after being opened for + writing, a change uevent will be synthesised.</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 printf-like string substitutions. The <option>RUN</option> + format chars gets applied after all rules have been processed, right before the program + is executed. It allows the use of device properties set by earlier matching + rules. For all other fields, substitutions are applied 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, follow the chain of parent devices and use the value + of the first attribute that matches. + 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 '+' char 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>The current list of symlinks, separated by a space character. The value is + only set if an earlier rule assigned a value, or during a remove events.</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 created temporary device node 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> |