X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=udev%2Fudev.xml;h=7b31173b21870f6cc159e0331a7d342ec4f44b81;hb=12a362be5c1982f80dbfb75bda070208a2c99cdf;hp=934fe628ae66dbdf226a1d0f97d46ff8b0ecb1e8;hpb=f045aa1cabab0ea0c3c3a6ee45cc9013a36c35b1;p=elogind.git
diff --git a/udev/udev.xml b/udev/udev.xml
index 934fe628a..7b31173b2 100644
--- a/udev/udev.xml
+++ b/udev/udev.xml
@@ -1,644 +1,707 @@
-
+
-
-
+
+ udev
-
-
- udev
- August 2005
- udev
-
-
-
- udev
- 7
-
-
-
-
- udev
- dynamic device management
-
-
- DESCRIPTION
- udev provides a dynamic device directory containing only the files for
- actually present devices. It creates or removes device node files in the
- /dev directory, or it renames network interfaces.
-
- Usually udev runs as udevd
- 8 and receives uevents directly from the
- kernel if a device is added or removed from the system.
-
- 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.
-
-
- CONFIGURATION
- udev configuration files are placed in /etc/udev/
- and /lib/udev/. All empty lines, or lines beginning with
- '#' will be 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:
-
-
-
-
- Specifies where to place the device nodes in the filesystem.
- The default value is /dev.
-
-
-
-
-
-
- The logging priority. Valid values are the numerical syslog priorities
- or their textual representations: ,
- and .
-
-
-
-
-
- Rules files
- The udev rules are read from the files located in the
- default rules directory /lib/udev/rules.d/,
- the custom rules directory /etc/udev/rules.d/
- and the temporary rules directory /dev/.udev/rules.d/.
- All rule files are sorted and processed in lexical order, regardless
- in which of these directories they live.
-
- Rule files are required to have a unique name, duplicate file names
- are ignored. Files in /etc/udev/rules.d/ have precedence
- over files with the same name in /lib/udev/rules.d/. This
- can be used to ignore a default rules file if needed.
-
- 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.
-
- 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.
-
- 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:
-
-
-
-
- Compare for equality.
-
-
-
-
-
-
- Compare for inequality.
-
-
-
-
-
-
- Assign a value to a key. Keys that represent a list, are reset
- and only this single value is assigned.
-
-
-
-
-
-
- Add the value to a key that holds a list of entries.
-
-
-
-
-
-
- Assign a value to a key finally; disallow any later changes,
- which may be used to prevent changes by any later rules.
-
-
-
-
- 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.
-
-
-
-
- Match the name of the event action.
-
-
-
-
-
-
- Match the devpath of the event device.
-
-
-
-
-
-
- Match the name of the event device.
-
-
-
-
-
-
- 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.
-
-
-
-
-
-
- Match the subsystem of the event device.
-
-
-
-
-
- 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.
-
-
-
-
-
- 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.
-
-
-
-
-
-
-
- Search the devpath upwards for a matching device name.
-
-
-
-
-
-
- Search the devpath upwards for a matching device subsystem name.
-
-
-
-
-
-
- Search the devpath upwards for a matching device driver name.
-
-
-
-
-
-
- Search the devpath upwards for a device with matching sysfs attribute values.
- If multiple 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.
-
-
-
-
-
-
- Match against a device property value.
-
-
-
-
-
-
- Test the existence of a file. An octal mode mask can be specified
- if needed.
-
-
-
-
-
-
- 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.
-
-
-
-
-
-
- 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.
-
-
-
-
- Most of the fields support a shell style pattern matching. The following
- pattern characters are supported:
-
-
-
-
- Matches zero, or any number of characters.
-
-
-
-
-
- Matches any single character.
-
-
-
-
-
- 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.
-
-
-
-
- The following keys can get values assigned:
-
-
-
-
- The name of the node to be created, or the name the network interface
- should be renamed to.
-
-
-
-
-
-
- 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.
-
-
-
-
-
-
- The permissions for the device node. Every specified value overwrites
- the compiled-in default value.
-
-
-
-
-
-
- The value that should be written to a sysfs attribute of the
- event device.
-
-
-
-
-
-
- Set a device property value. Property names with a leading '.'
- are not stored in the database or exported to external tool or events.
-
-
-
-
-
-
- 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 specified string starts with
- , 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.
-
-
-
-
-
-
- Named label where a GOTO can jump to.
-
-
-
-
-
-
- Jumps to the next LABEL with a matching name
-
-
-
-
-
-
- Import a set of variables as device properties,
- depending on type:
-
-
-
-
- Execute an external program specified as the assigned value and
- import its output, which must be in environment key format.
-
-
-
-
-
- Import a text file specified as the assigned value, which must be in
- environment key format.
-
-
-
-
-
- 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
- comparisons).
-
-
-
- If no option is given, udev will choose between
- and based on the executable bit of the file
- permissions.
-
-
-
-
-
-
- Wait for a file to become available.
-
-
-
-
-
-
- Rule and device options:
-
-
-
-
- Stops further rules application. No later rules will have
- any effect.
-
-
-
-
-
- Ignore this event completely.
-
-
-
-
-
- Do not remove the device node when the device goes away. This may be
- useful as a workaround for broken device drivers.
-
-
-
-
-
- Specify the priority of the created symlinks. Devices with higher
- priorities overwrite existing symlinks of other devices. The default is 0.
-
-
-
-
-
- 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.
-
-
-
-
-
- Number of seconds an event will wait for operations to finish, before it
- will terminate itself.
-
-
-
-
-
- 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.
-
-
-
-
-
- Watch the device node with inotify, when closed after being opened for
- writing, a change uevent will be synthesised.
-
-
-
-
-
-
-
- The , , ,
- , , and
- fields support simple printf-like string substitutions. The
- 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:
-
-
- ,
-
- The kernel name for this device.
-
-
-
-
- ,
-
- The kernel number for this device. For example, 'sda3' has
- kernel number of '3'
-
-
-
-
- ,
-
- The devpath of the device.
-
-
-
-
- ,
-
- The name of the device matched while searching the devpath upwards for
- , , and .
-
-
-
-
-
-
-
- The driver name of the device matched while searching the devpath upwards for
- , , and .
-
-
-
-
-
- ,
-
- 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.
-
-
-
-
- ,
-
- A device property value.
-
-
-
-
- ,
-
- The kernel major number for the device.
-
-
-
-
- ,
-
- The kernel minor number for the device.
-
-
-
-
- ,
-
- 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 '+' char this part plus all remaining parts
- of the result string are substituted:
-
-
-
-
- ,
-
- The node name of the parent device.
-
-
-
-
-
-
- The current name of the device node. If not changed by a rule, it is the
- name of the kernel device.
-
-
-
-
-
-
- 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.
-
-
-
-
- ,
-
- The udev_root value.
-
-
-
-
- ,
-
- The sysfs mount point.
-
-
-
-
- ,
-
- The name of a created temporary device node to provide access to
- the device from a external program before the real node is created.
-
-
-
-
-
-
- The '%' character itself.
-
-
-
-
-
-
- The '$' character itself.
-
-
-
-
-
-
- AUTHOR
- Written by Greg Kroah-Hartman greg@kroah.com and
- Kay Sievers kay.sievers@vrfy.org. With much help from
- Dan Stekloff and many others.
-
-
-
- SEE ALSO
-
- udevd8
- ,
-
- udevadm8
-
-
-
-
-
+ udev
+
+
+
+ udev
+ 7
+
+
+
+ udev
+ Linux dynamic device management
+
+
+ Description
+ udev supplies the system software with device events, manages permissions
+ of device nodes and may create additional symlinks in the /dev
+ 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.
+
+ The udev daemon, udevd
+ 8, receives device uevents directly from
+ the kernel whenever a device is added or removed from the system, or it changes its
+ state. When udev receives a device event, it matches its configured set of rules
+ against various device attributes to identify the device. Rules that match may
+ provide additional device information to be stored in the udev database or
+ to be used to create meaningful symlink names.
+
+ All device information udev processes is stored in the udev database and
+ sent out to possible event subscribers. Access to all stored data and the event
+ sources is provided by the library libudev.
+
+
+ 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:
+
+
+
+
+ Specifies where to place the device nodes in the filesystem.
+ The default value is /dev.
+
+
+
+
+
+
+ The logging priority. Valid values are the numerical syslog priorities
+ or their textual representations: ,
+ and .
+
+
+
+
+
+ Rules files
+ The udev rules are read from the files located in the
+ system rules directory /usr/lib/udev/rules.d,
+ the local administration directory /etc/udev/rules.d
+ and the volatile runtime directory /run/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 /run
+ have the highest priority, files in /etc take precedence
+ over files with the same name in /lib. This can be
+ used to overwrite a system rules 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.
+
+ Every line in the rules file contains at least one key-value pair.
+ There are two kind of keys: match and assignment.
+ If all match keys are matching against its value, the rule gets applied and the
+ assignment keys get the specified value assigned.
+
+ 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.
+
+ A rule consists of a comma-separated list of one or more key-value pairs.
+ Each key has a distinct operation, depending on the used operator. Valid
+ operators are:
+
+
+
+
+ Compare for equality.
+
+
+
+
+
+
+ Compare for inequality.
+
+
+
+
+
+
+ Assign a value to a key. Keys that represent a list are reset
+ and only this single value is assigned.
+
+
+
+
+
+
+ Add the value to a key that holds a list of entries.
+
+
+
+
+
+
+ Assign a value to a key finally; disallow any later changes.
+
+
+
+
+ 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.
+
+
+
+
+ Match the name of the event action.
+
+
+
+
+
+
+ Match the devpath of the event device.
+
+
+
+
+
+
+ Match the name of the event device.
+
+
+
+
+
+
+ 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.
+
+
+
+
+
+
+ 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.
+
+
+
+
+
+
+
+ Match the subsystem of the event device.
+
+
+
+
+
+ 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.
+
+
+
+
+
+ Match sysfs attribute values of the event device. Trailing
+ whitespace in the attribute values is ignored unless the specified match
+ value itself contains trailing whitespace.
+
+
+
+
+
+
+
+ Search the devpath upwards for a matching device name.
+
+
+
+
+
+
+ Search the devpath upwards for a matching device subsystem name.
+
+
+
+
+
+
+ Search the devpath upwards for a matching device driver name.
+
+
+
+
+
+
+ Search the devpath upwards for a device with matching sysfs attribute values.
+ If multiple 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.
+
+
+
+
+
+
+ Search the devpath upwards for a device with matching tag.
+
+
+
+
+
+
+ Match against a device property value.
+
+
+
+
+
+
+ Match against a device tag.
+
+
+
+
+
+
+ Test the existence of a file. An octal mode mask can be specified
+ if needed.
+
+
+
+
+
+
+ Execute a program to determine whether there
+ is a match; the key is true if the program returns
+ successfully. The device properties are made available to the
+ executed program in the environment. The program's stdout
+ is available in the RESULT key.
+
+
+
+
+
+
+ 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.
+
+
+
+
+ Most of the fields support shell-style pattern matching. The following
+ pattern characters are supported:
+
+
+
+
+ Matches zero or more characters.
+
+
+
+
+
+ Matches any single character.
+
+
+
+
+
+ Matches any single character specified within the brackets. For
+ example, the pattern string 'tty[SR]' would match either 'ttyS' or 'ttyR'.
+ Ranges are also supported via the '-' character.
+ For example, to match on the range of all digits, the pattern [0-9] could
+ be used. If the first character following the '[' is a '!', any characters
+ not enclosed are matched.
+
+
+
+
+ The following keys can get values assigned:
+
+
+
+
+ What a network interface should be named.
+ Also, as a temporary workaround, this is what a device node
+ should be named; usually the kernel provides the defined node name or creates
+ and removes the node before udev even receives any event. Changing
+ the node name from the kernel's default creates inconsistencies
+ and is not supported. If the kernel and NAME specify different names,
+ an error is logged. udev is only expected to handle device node
+ permissions and to create additional symlinks, not to change
+ kernel-provided device node names. Instead of renaming a device node,
+ SYMLINK should be used. However, symlink names must never conflict with
+ device node names, as that would result in unpredictable behavior.
+
+
+
+
+
+
+ The name of a symlink targeting the node. Every matching rule adds
+ this value to the list of symlinks to be created. Multiple symlinks may be
+ specified by separating the names by the space character. In case multiple
+ devices claim the same name, the link always points to the device with
+ the highest link_priority. If the current device goes away, the links are
+ re-evaluated and the device with the next highest link_priority becomes the owner of
+ the link. If no link_priority is specified, the order of the devices (and
+ which one of them owns the link) is undefined. Also, symlink names must
+ never conflict with the kernel's default device node names, as that would
+ result in unpredictable behavior.
+
+
+
+
+
+
+
+ The permissions for the device node. Every specified value overwrites
+ the compiled-in default value.
+
+
+
+
+
+
+ The value that should be written to a sysfs attribute of the
+ event device.
+
+
+
+
+
+
+ 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).
+
+
+
+
+
+
+ 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.
+
+
+
+
+
+
+ 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 no absolute path is given, the program is expected to live in
+ the directory provided at compile-time to configure via --libexecdir
+ (this is usually /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.
+
+
+
+
+
+
+ A named label to which a GOTO may jump.
+
+
+
+
+
+
+ Jumps to the next LABEL with a matching name.
+
+
+
+
+
+
+ Import a set of variables as device properties,
+ depending on type:
+
+
+
+
+ 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 .
+
+
+
+
+
+ Import a text file specified as the assigned value, the content
+ of which must be in environment key format.
+
+
+
+
+
+ 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.
+
+
+
+
+
+ Import a single property from the kernel command line. For simple flags
+ the value of the property is set to '1'.
+
+
+
+
+
+ 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
+ comparisons).
+
+
+
+
+
+
+
+
+
+ Wait for a file to become available or until a timeout of
+ 10 seconds expires. The path is relative to the sysfs device;
+ if no path is specified, this waits for an attribute to appear.
+
+
+
+
+
+
+ Rule and device options:
+
+
+
+
+ Specify the priority of the created symlinks. Devices with higher
+ priorities overwrite existing symlinks of other devices. The default is 0.
+
+
+
+
+
+ Number of seconds an event waits for operations to finish before
+ giving up and terminating itself.
+
+
+
+
+
+ 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.
+
+
+
+
+
+ Apply the permissions specified in this rule to the static device node with
+ the specified name. Static device nodes might be provided by kernel modules
+ or copied from /usr/lib/udev/devices. These nodes might not have
+ a corresponding kernel device at the time udevd is started; they can trigger
+ automatic kernel module loading.
+
+
+
+
+
+ Watch the device node with inotify; when the node is closed after being opened for
+ writing, a change uevent is synthesized.
+
+
+
+
+
+ Disable the watching of a device node with inotify.
+
+
+
+
+
+
+
+ The , , ,
+ , , and
+ fields support simple string substitutions. The
+ 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:
+
+
+ ,
+
+ The kernel name for this device.
+
+
+
+
+ ,
+
+ The kernel number for this device. For example, 'sda3' has
+ kernel number of '3'
+
+
+
+
+ ,
+
+ The devpath of the device.
+
+
+
+
+ ,
+
+ The name of the device matched while searching the devpath upwards for
+ , , and .
+
+
+
+
+
+
+
+ The driver name of the device matched while searching the devpath upwards for
+ , , and .
+
+
+
+
+
+ ,
+
+ The value of a sysfs attribute found at the device where
+ all keys of the rule have matched. If the matching device does not have
+ such an attribute, and a previous KERNELS, SUBSYSTEMS, DRIVERS, or
+ ATTRS test selected a parent device, then the attribute from that
+ parent device is used.
+ If the attribute is a symlink, the last element of the symlink target is
+ returned as the value.
+
+
+
+
+ ,
+
+ A device property value.
+
+
+
+
+ ,
+
+ The kernel major number for the device.
+
+
+
+
+ ,
+
+ The kernel minor number for the device.
+
+
+
+
+ ,
+
+ 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:
+
+
+
+
+ ,
+
+ The node name of the parent device.
+
+
+
+
+
+
+ The current name of the device node. If not changed by a rule, it is the
+ name of the kernel device.
+
+
+
+
+
+
+ A space-separated list of the current symlinks. The value is
+ only set during a remove event or if an earlier rule assigned a value.
+
+
+
+
+ ,
+
+ The udev_root value.
+
+
+
+
+ ,
+
+ The sysfs mount point.
+
+
+
+
+ ,
+
+ The name of a temporary device node created to provide access to
+ the device from a external program before the real node is created.
+
+
+
+
+
+
+ The '%' character itself.
+
+
+
+
+
+
+ The '$' character itself.
+
+
+
+
+
+
+ Author
+ Written by Greg Kroah-Hartman greg@kroah.com and
+ Kay Sievers kay.sievers@vrfy.org. With much help from
+ Dan Stekloff and many others.
+
+
+
+ See Also
+
+ udevd8
+ ,
+
+ udevadm8
+
+
+