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diff --git a/docs/udev.xml b/docs/udev.xml new file mode 100644 index 0000000000..02dcd2586a --- /dev/null +++ b/docs/udev.xml @@ -0,0 +1,545 @@ +<?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> + <articleinfo> + <title>xmlto</title> + <author> + <firstname>Kay</firstname> + <surname>Sievers</surname> + <email>kay.sievers@vrfy.org</email> + </author> + <copyright> + <year>2005</year> + <holder>Kay Sievers</holder> + </copyright> + </articleinfo> + + <section> + <title>udev</title> + <refentry> + <refentryinfo> + <title>udev</title> + <date>August 2005</date> + <productname>udev</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>udev</refentrytitle> + <manvolnum>8</manvolnum> + </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 form the system. The program + <command>udev</command> itself may be used as an event handler in situations, + where running the daemon is not appropriate, like in initramfs.</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>All udev configuration files are placed in <filename>/etc/udev/*</filename>. + Every file consist of a set of lines of text. 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_db</option></term> + <listitem> + <para>The name and location of the udev database. The default value is + <filename>/dev/.udevdb</filename>.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>udev_rules</option></term> + <listitem> + <para>The name of the udev rules file or directory to look for files + with the suffix <filename>.rules</filename>. Multiple rule files are + read in lexical order. The default value is + <filename>/etc/udev/rules.d</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 + <filename>/etc/udev/rules.d</filename> directory or at the location specified + value in the configuraton file. Every line in the rules file contains at least + one key value pair. There are two kind of keys, match and assignement keys. + If all match keys are matching against its value, the rule gets applied and the + assign keys get the specified value assigned. 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 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 non-equality.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>=</option></term> + <listitem> + <para>Asign 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:</para> + <variablelist> + <varlistentry> + <term><option>ACTION</option></term> + <listitem> + <para>Match the kernel action name.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>KERNEL</option></term> + <listitem> + <para>Match the kernel device name</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>DEVPATH</option></term> + <listitem> + <para>Match the kernel devpath.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>SUBSYSTEM</option></term> + <listitem> + <para>Match the kernel subsystem name</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>BUS</option></term> + <listitem> + <para>Match the typ of bus the device is connected to.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>DRIVER</option></term> + <listitem> + <para>Match the kernel driver name.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>ID</option></term> + <listitem> + <para>Match the device number on the bus.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>ENV{<replaceable>key</replaceable>}</option></term> + <listitem> + <para>Match against the value of an environment key. Depending on + the specified operation, this key is also used as a assignment.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>SYSFS{<replaceable>filename</replaceable>}</option></term> + <listitem> + <para>Match the sysfs attribute value. Up to five values can be specified. + Trailing whitespace is ignored, if the specified match value does not contain + trailing whitespace itself.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>PROGRAM</option></term> + <listitem> + <para>Execute external program. The key is true, if the program returns + without exit code zero. The whole event environment is available to the + executed program. The program's output printed to stdout is available for + 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. + 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 a 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 over writes + the compiled-in default value.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>ENV{<replaceable>key</replaceable>}</option></term> + <listitem> + <para>Export the key to the environment. Depending on the specified + operation, this key is also used as a match.</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.</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 gname</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>IMPORT{<replaceable>type</replaceable>}</option></term> + <listitem> + <para>Import the printed result or the content of a file in environment key + format into the event environment. <option>program</option> will execute an + external program and read its output. <option>file</option> will inport a + text file. If no option is given, udev will determine it from the executable + bit of of the file permissions.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>WAIT_FOR_SYSFS</option></term> + <listitem> + <para>Wait for the specified sysfs file of the device to be created. May be used + to fight agains timing issues wth the kernel.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>OPTIONS</option></term> + <listitem> + <para><option>last_rule</option> stops further rules application. No later rules + will have any effect. + <option>ignore_device</option> will ignore this event completely. + <option>ignore_remove</option> will ignore any later remove event for this + device. This may be useful as a workaround for broken device drivers. + <option>all_partitions</option> will create device nodes for all available partitions of + a block device. This may be useful for removable media.</para> + </listitem> + </varlistentry> + </variablelist> + + <para>The <option>NAME</option>, <option>SYMLINK</option>, <option>PROGRAM</option>, + <option>OWNER</option> and <option>GROUP</option> fields support simple + printf-like string substitutions:</para> + <variablelist> + <varlistentry> + <term><option>%k</option>, <option>$kernel</option></term> + <listitem> + <para>The kernel name for this device.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>%b</option>, <option>$id</option></term> + <listitem> + <para>The kernel bus id for this device.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>%n</option>, <option>$number</option></term> + <listitem> + <para>The kernel number for this device. For example, 'sda3' has + kernel number of '3'</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>%p</option>, <option>$devpath</option></term> + <listitem> + <para>The devpath of the device.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>%s{<replaceable>file</replaceable>}</option>, <option>$sysfs{<replaceable>file</replaceable>}</option></term> + <listitem> + <para>The content of a sysfs attribute.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>%e{<replaceable>key</replaceable>}</option>, <option>$env{<replaceable>key</replaceable>}</option></term> + <listitem> + <para>The value of an environment variable.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>%m</option>, <option>$major</option></term> + <listitem> + <para>The kernel major number for the device.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>%M</option> <option>$minor</option></term> + <listitem> + <para>The kernel minor number for the device.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>%c</option>, <option>$result</option></term> + <listitem> + <para>The string returned by the external program requested with PROGRAM. + A single part of the string, separated by a space character may be selected + by specifying the part number as an attribute: <option>%c{N}</option>. + If the number is followed by the '+' char this part plus all remaining parts + of the result string are substituted: <option>%c{N+}</option></para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>%e</option>, <option>$enum</option></term> + <listitem> + <para>If a device node already exists with the name, the smallest next free + number is used. This can be used to create compatibility symlinks and enumerate + devices of the same type originating from different kernel subsystems.</para> + <para>Note: The use of the enumeration facility is unreliable for events that + request a number at the same time. The use of enumerations in todays setups + where devices can come and go at any time is not recomended.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>%P</option>, <option>$parent</option></term> + <listitem> + <para>The node name of the parent device.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>%r</option>, <option>$root</option></term> + <listitem> + <para>The udev_root value.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>%N</option>, <option>$tempnode</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>ENVIRONMENT</title> + <variablelist> + <varlistentry> + <term><option>ACTION</option></term> + <listitem> + <para><replaceable>add</replaceable> or <replaceable>remove</replaceable> signifies + the addition or the removal of a device.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>DEVPATH</option></term> + <listitem> + <para>The sysfs devpath without the mountpoint but a leading slash.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>SUBSYSTEM</option></term> + <listitem> + <para>The kernel subsystem the device belongs to.</para> + </listitem> + </varlistentry> + + <varlistentry> + <term><option>UDEV_LOG</option></term> + <listitem> + <para>Overrides the syslog priority specified in the config file.</para> + </listitem> + </varlistentry> + </variablelist> + </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 <email>dsteklof@us.ibm.com</email> and many others.</para> + </refsect1> + + <refsect1> + <title>SEE ALSO</title> + <para><citerefentry> + <refentrytitle>udev</refentrytitle><manvolnum>8</manvolnum> + </citerefentry>, + <citerefentry> + <refentrytitle>udevinfo</refentrytitle><manvolnum>8</manvolnum> + </citerefentry>, + <citerefentry> + <refentrytitle>udevd</refentrytitle><manvolnum>8</manvolnum> + </citerefentry>, + <citerefentry> + <refentrytitle>udevmonitor</refentrytitle><manvolnum>8</manvolnum> + </citerefentry></para> + </refsect1> + </refentry> + </section> +</article> |