X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fudev.xml;h=f107482329961362bbe3b22d6b044f3abfd2a876;hp=773635ecf77ed28212bdcfefe64e762ae908bfa5;hb=0778c3db87383ffcbe0fd303019c8b7e96b75394;hpb=6b76fa66199967b4ec71854f717d0b8ee94497c4 diff --git a/man/udev.xml b/man/udev.xml index 773635ecf..f10748232 100644 --- a/man/udev.xml +++ b/man/udev.xml @@ -30,7 +30,7 @@ udev - Linux dynamic device management + Dynamic device management Description @@ -54,49 +54,27 @@ sources is provided by the library libudev. - Configuration - udev configuration files are placed in /etc/udev - and /usr/lib/udev. All empty lines or lines beginning with - '#' are ignored. - - Configuration file - udev expects its main configuration file at /etc/udev/udev.conf. - It consists of a set of variables allowing the user to override default udev values. - The following variables can be set: - - - udev_log - - The logging priority. Valid values are the numerical syslog priorities - or their textual representations: , - and . - - - - - - Rules files + Rules Files The udev rules are read from the files located in the system rules directory /usr/lib/udev/rules.d, the volatile runtime directory /run/udev/rules.d and the local administration directory /etc/udev/rules.d. All rules files are collectively sorted and processed in lexical order, regardless of the directories in which they live. However, files with - identical file names replace each other. Files in /etc + identical filenames replace each other. Files in /etc have the highest priority, files in /run take precedence over files with the same name in /lib. This can be used to override a system-supplied rules file with a local file if needed; a symlink in /etc with the same name as a rules file in /lib, pointing to /dev/null, - disables the rules file entirely. - - Rule files must have the extension .rules; other - extensions are ignored. + disables the rules file entirely. Rule files must have the extension + .rules; other extensions are ignored. Every line in the rules file contains at least one key-value pair. + Except for empty lines or lines beginning with #, which are ignored. There are two kinds 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. + If all match keys match against their values, the rule gets applied and the + assignment keys get the specified values assigned. A matching rule may rename a network interface, add symlinks pointing to the device node, or run a specified program as part of @@ -148,30 +126,30 @@ 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. - + - + ACTION Match the name of the event action. - + DEVPATH Match the devpath of the event device. - + KERNEL Match the name of the event device. - + NAME Match the name of a network interface. It can be used once the NAME key has been set in one of the preceding rules. @@ -179,7 +157,7 @@ - + SYMLINK 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 @@ -189,20 +167,20 @@ - + SUBSYSTEM Match the subsystem of the event device. - + DRIVER 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. - + ATTR{filename} Match sysfs attribute values of the event device. Trailing whitespace in the attribute values is ignored unless the specified match @@ -212,59 +190,59 @@ - + KERNELS Search the devpath upwards for a matching device name. - + SUBSYSTEMS Search the devpath upwards for a matching device subsystem name. - + DRIVERS Search the devpath upwards for a matching device driver name. - + ATTRS{filename} Search the devpath upwards for a device with matching sysfs attribute values. - If multiple matches are specified, all of them + If multiple ATTRS 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. - + TAGS Search the devpath upwards for a device with matching tag. - + ENV{key} Match against a device property value. - + TAG Match against a device tag. - + TEST{octal mode mask} Test the existence of a file. An octal mode mask can be specified if needed. @@ -272,7 +250,7 @@ - + PROGRAM Execute a program to determine whether there is a match; the key is true if the program returns @@ -280,12 +258,12 @@ executed program in the environment. The program's stdout is available in the RESULT key. This can only be used for very short-running foreground tasks. For details - see . + see RUN. - + RESULT 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. @@ -293,7 +271,7 @@ - Most of the fields support shell-style pattern matching. The following + Most of the fields support shell glob pattern matching. The following pattern characters are supported: @@ -312,19 +290,20 @@ [] 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. + 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. + be used. If the first character following the [ is a + !, any characters not enclosed are matched. The following keys can get values assigned: - + - + NAME The name to use for a network interface. The name of a device node cannot be changed by udev, only additional symlinks can be created. @@ -332,14 +311,14 @@ - + SYMLINK The name of a symlink targeting the node. Every matching rule adds this value to the list of symlinks to be created. The set of characters to name a symlink is limited. Allowed - characters are [0-9A-Za-z#+-.:=@_/], valid utf8 character sequences, - and "\x00" hex encoding. All other characters are replaced by - a '_' character. + characters are 0-9A-Za-z#+-.:=@_/, valid UTF-8 character + sequences, and \x00 hex encoding. All other + characters are replaced by a _ character. 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 @@ -354,7 +333,7 @@ - , , + OWNER, GROUP, MODE The permissions for the device node. Every specified value overrides the compiled-in default value. @@ -362,7 +341,7 @@ - + ATTR{key} The value that should be written to a sysfs attribute of the event device. @@ -370,16 +349,16 @@ - + ENV{key} - Set a device property value. Property names with a leading '.' + 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). - + TAG 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 @@ -392,14 +371,31 @@ - + RUN{type} - Add a program to the list of programs to be executed for a specific - device. - If no absolute path is given, the program is expected to live in - /usr/lib/udev, 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. + Add a program to the list of programs to be executed after processing all the + rules for a specific event, depending on type: + + + program + + Execute an external program specified as the assigned + value. If no absolute path is given, the program is expected to live in + /usr/lib/udev, otherwise the absolute path must be specified. + This is the default if no type is + specified. + + + + builtin + + As program, but use one of the built-in programs rather + than an external one. + + + + The program name and following arguments are separated by spaces. + Single quotes can be used to specify arguments with spaces. This can only be used for very short-running foreground tasks. Running an event process for a long period of time may block all further events for this or a dependent device. @@ -410,21 +406,21 @@ - + LABEL A named label to which a GOTO may jump. - + GOTO Jumps to the next LABEL with a matching name. - + IMPORT{type} Import a set of variables as device properties, depending on type: @@ -435,10 +431,17 @@ 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 . + and quoting work like in RUN. + builtin + + Similar to program, but use one of the + built-in programs rather than an external one. + + + file Import a text file specified as the assigned value, the content @@ -457,7 +460,7 @@ cmdline Import a single property from the kernel command line. For simple flags - the value of the property is set to '1'. + the value of the property is set to 1. @@ -466,7 +469,7 @@ Import the stored keys from the parent device by reading the database entry of the parent device. The value assigned to is used as a filter of key names - to import (with the same shell-style pattern matching used for + to import (with the same shell glob pattern matching used for comparisons). @@ -477,7 +480,7 @@ - + WAIT_FOR Wait for a file to become available or until a timeout of 10 seconds expires. The path is relative to the sysfs device; @@ -486,10 +489,10 @@ - + OPTIONS Rule and device options: - + @@ -516,9 +519,13 @@ Apply the permissions specified in this rule to the static device node with - the specified name. Static device node creation can be requested by kernel modules. - These nodes might not have a corresponding kernel device at the time systemd-udevd is - started; they can trigger automatic kernel module loading. + the specified name. Also, for every tag specified in this rule, create a symlink + in the directory + /run/udev/static_node-tags/tag + pointing at the static device node with the specified name. Static device node + creation is performed by systemd-tmpfiles before systemd-udevd is started. The + static nodes might not have a corresponding kernel device; they are used to + trigger automatic kernel module loading when they are accessed. @@ -539,14 +546,14 @@ - The , , , - , , and - fields support simple string substitutions. The + The NAME, SYMLINK, PROGRAM, + OWNER, GROUP, MODE and RUN + fields support simple string substitutions. The RUN 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: - + , @@ -557,8 +564,8 @@ , - The kernel number for this device. For example, 'sda3' has - kernel number of '3' + The kernel number for this device. For example, + sda3 has kernel number 3. @@ -626,9 +633,9 @@ 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: . - If the number is followed by the '+' character, this part plus all remaining parts - of the result string are substituted: + by specifying the part number as an attribute: %c{N}. + If the number is followed by the + character, this part plus all remaining parts + of the result string are substituted: %c{N+}. @@ -677,20 +684,54 @@ - %% + - The '%' character itself. + The % character itself. - $$ + - The '$' character itself. + The $ character itself. - + + + Hardware Database Files + The hwdb files are read from the files located in the + system hwdb directory /usr/lib/udev/hwdb.d, + the volatile runtime directory /run/udev/hwdb.d + and the local administration directory /etc/udev/hwdb.d. + All hwdb files are collectively sorted and processed in lexical order, + regardless of the directories in which they live. However, files with + identical filenames replace each other. Files in /etc + have the highest priority, files in /run take precedence + over files with the same name in /lib. This can be + used to override a system-supplied hwdb file with a local file if needed; + a symlink in /etc with the same name as a hwdb file in + /lib, pointing to /dev/null, + disables the hwdb file entirely. hwdb files must have the extension + .hwdb; other extensions are ignored. + + The hwdb file contains data records consisting of matches and + associated key-value pairs. Every record in the hwdb starts with one or + more match string, specifying a shell glob to compare the database + lookup string against. Multiple match lines are specified in additional + consecutive lines. Every match line is compared indivdually, they are + combined by OR. Every match line must start at the first character of + the line. + + The match lines are followed by one or more key-value pair lines, which + are recognized by a leading space character. The key name and value are separated + by =. An empty line signifies the end + of a record. Lines beginning with # are ignored. + + The content of all hwdb files is read by + udevadm8 + and compiled to a binary database located at /etc/udev/hwdb.bin. + During runtime only the binary database is used.