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diff --git a/udev/udev.xml b/udev/udev.xml new file mode 100644 index 0000000000..c740c0d807 --- /dev/null +++ b/udev/udev.xml @@ -0,0 +1,639 @@ +<?xml version='1.0'?> +<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> + +<article> + <section> + <title>udev</title> + <refentry> + <refentryinfo> + <title>udev</title> + <date>August 2005</date> + <productname>udev</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>udev</refentrytitle> + <manvolnum>7</manvolnum> + <refmiscinfo class="version"></refmiscinfo> + </refmeta> + + <refnamediv> + <refname>udev</refname> + <refpurpose>dynamic device management</refpurpose> + </refnamediv> + + <refsect1><title>DESCRIPTION</title> + <para>udev provides a dynamic device directory containing only the files for + actually present devices. It creates or removes device node files in the + <filename>/dev</filename> directory, or it renames network interfaces.</para> + + <para>Usually udev runs as <citerefentry><refentrytitle>udevd</refentrytitle> + <manvolnum>8</manvolnum></citerefentry> and receives uevents directly from the + kernel if a device is added or removed from the system.</para> + + <para>If udev receives a device event, it matches its configured rules + against the available device attributes provided in sysfs to identify the device. + Rules that match may provide additional device information or specify a device + node name and multiple symlink names and instruct udev to run additional programs + as part of the device event handling.</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. 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 specify the name of the device node, add a symlink + pointing to the node, or run a specified program as part of the event handling. + If no matching rule is found, the default device node name is used.</para> + + <para>A rule may consist 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 non-equality.</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>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. Up to five + <option>ATTR</option> keys can be specified per rule. Trailing + whitespace in the attribute values is ignored, if the specified match + value does not contain trailing whitespace itself. Depending on the type + of operator, this key is also used to set the value of a sysfs attribute. + </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. + Up to five <option>ATTRS</option> keys can be specified per rule, but 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 the value of an environment variable. Up to five <option>ENV</option> + keys can be specified per rule. Depending on the type of operator, this key is also used + to export a variable to the environment.</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 external program. The key is true, if the program returns + with exit code zero. The whole event environment is available to the + executed program. 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 of the node to be created, or the name the network interface + should be renamed to. Only one rule can set the node name, all later rules with + a NAME key will be ignored.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>SYMLINK</option></term> + <listitem> + <para>The name of a symlink targeting the node. Every matching rule can add + this value to the list of symlinks to be created along with the device node. + Multiple symlinks may be specified by separating the names by the space + character.</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. Depending on the type of operator, this key is also + used to match against the value of a sysfs attribute.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>ENV{<replaceable>key</replaceable>}</option></term> + <listitem> + <para>Export a variable to the environment. Depending on the type of operator, + this key is also to match against an environment variable.</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 the specifiefd string starts with + <option>socket:<replaceable>path</replaceable></option>, all current event + values will be passed to the specified socket, as a message in the same + format the kernel sends an uevent. If the first character of the specified path + is an @ character, an abstract namespace socket is used, instead of an existing + socket file.</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 into the event environment, + 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.</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>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.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>OPTIONS</option></term> + <listitem> + <para>Rule and device options:</para> + <variablelist> + <varlistentry> + <term><option>last_rule</option></term> + <listitem> + <para>Stops further rules application. No later rules will have + any effect.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><option>ignore_device</option></term> + <listitem> + <para>Ignore this event completely.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><option>ignore_remove</option></term> + <listitem> + <para>Do not remove the device node when the device goes away. This may be + useful as a workaround for broken device drivers.</para> + </listitem> + </varlistentry> + <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>all_partitions</option></term> + <listitem> + <para>Create the device nodes for all available partitions of a block device. + This may be useful for removable media devices where media changes are not + detected.</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> + </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 the complete environment 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>$env{<replaceable>key</replaceable>}</option>, <option>%E{<replaceable>key</replaceable>}</option></term> + <listitem> + <para>The value of an environment variable.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>$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> + <para>The count of characters to be substituted may be limited by specifying + the format length value. For example, '%3s{file}' will only + insert the first three characters of the sysfs attribute</para> + </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> |