udev \- Linux configurable dynamic device naming support
.SH SYNOPSIS
.BI udev " hotplug-subsystem"
+.br
+.B udev
+.RI "[-q " query_type " -p " sysfs_path "] [-drVh]"
.SH "DESCRIPTION"
.B udev
creates or removes device node files usually located in the /dev directory.
.B udev
reads the sysfs directory of the given device to collect device attributes
like label, serial number or bus device number.
-These attributes are treated as a key
-to determine a unique name for device file creation.
+These attributes may used as keys to determine a
+unique name for device file creation.
.B udev
maintains a database for devices present on the system.
.br
On device removal,
.B udev
-queries the internal database for the name of the device file to be deleted.
+queries its database for the name of the device file to be deleted.
+.SH "OPTIONS"
+.B udev
+normally is called by
+.B hotplug
+with the subsystem as argument and various environment variables set.
+.br
+It may also called with the following options:
+.TP
+.B -V
+Print the version information.
+.TP
+.B -r
+Print the the
+.B udev_root
+directory. When used in conjunction with a query for the node name, the
+.B udev_root
+will be prepended.
+.TP
+.BI -q " query_type"
+Query the database for specified value of a created device node.
+Valid types are:
+.BR name ", " symlink ", " owner " or " group .
+.TP
+.BI -p " sysfs_path"
+Specify the sysfs path needed for the query.
+.TP
+.B -d
+Dump the whole database.
+.TP
+.B -h
+Print help text.
.SH "CONFIGURATION"
All
.B udev
# udev_permissions - The name and location of the udev permission file
udev_permissions="/etc/udev/udev.permissions"
-# default_mode - set the default mode for all nodes that have no
+# default_mode - set the default mode for all nodes that have no
# explicit match in the permissions file
default_mode="0666"
.fi
.I /etc/udev/udev.conf
file.
.P
-Every line in the rules file define the mapping between device attributes and
-the device file name. It starts with a keyword defining the method used to
-match, followed by one ore more keys to compare and the filename for the
-device. One ore more optional symlinks targeting the node may be specified.
+Every line in the rules file defines the mapping between device attributes
+and the device file name. One ore more keys are specified to match a rule
+with the current device. If all keys are matching, the rule will be applied
+and the name is used for the device node. One or more optional symlinks
+targeting the node may be specified.
.br
-If no matching configuration is found, the default kernel device name
-is used.
+If no matching rule is found, the default kernel device name is used.
.P
The line format is:
.sp
-.I method, key,[key,...] name [, symlink]
+.I key,[key,...] name [, symlink]
.sp
-where valid methods with corresponding keys are:
+where keys are:
.TP
-.B CALLOUT
-calling external program, that returns a string to match. The
-.BR BUS
-key is optional, but if specified, the sysfs device bus must be able to be
-detemined by a "device" symlink.
-.br
-.RB "keys: " BUS ", " PROGRAM ", " ID
+.B BUS
+Match the bus type of the device.
+(The sysfs device bus must be able to be determined by a "device" symlink.)
.TP
-.B LABEL
-device label or serial number, like USB serial number, SCSI UUID or
-file system label. Up to 5 different sysfs files can be checked, with
-all of the values being required in order to match the rule.
-.br
-.RB "keys: " BUS ", " SYSFS_
+.B KERNEL
+Match the kernel device name.
.TP
-.B NUMBER
-device number on the bus, like PCI bus id
-.br
-.RB "keys: " BUS ", " ID
+.B ID
+Match the device number on the bus, like PCI bus id.
.TP
-.B TOPOLOGY
-device position on bus, like physical port of USB device
-.br
-.RB "keys: " BUS ", " PLACE
+.B PLACE
+Match the topological position on bus, like physical port of USB device
.TP
-.B REPLACE
-string replacement of the kernel device name
-.br
-.RB "key: " KERNEL
-.P
-The methods are applied in the following order:
-.BR CALLOUT ", " LABEL ", " NUMBER ", " TOPOLOGY ", " REPLACE "."
+.BI SYSFS_ filename
+Match sysfs device attribute like label, vendor, USB serial number, SCSI UUID
+or file system label. Up to 5 different sysfs files can be checked, with
+all of the values being required in order to match the rule.
+.TP
+.B PROGRAM
+Call external program. This key is valid if the program returns successful.
+The string returned by the program may additionally matched with the
+.B RESULT
+key.
+.TP
+.B RESULT
+Match the returned string of the last
+.B PROGRAM
+call. This key may used in any following rule after a
+.B PROGRAM
+call.
.P
.RB "The " NAME " ," SYMLINK " and " PROGRAM
fields support simple printf-like string substitution:
The bus id for the device.
.TP
.B %c
-The CALLOUT program returned string.
-(This does not work within the PROGRAM field for the obvious reason.)
+The
+.B PROGRAM
+returned string.
+(This does not work within the
+.B PROGRAM
+field for the obvious reason.)
.TP
.B %D
Use the devfs style disk name for this device.
.sp
.nf
# if /sbin/scsi_id returns "OEM 0815" device will be called disk1
-CALLOUT, BUS="scsi", PROGRAM="/sbin/scsi_id", ID="OEM 0815", NAME="disk1"
+BUS="scsi", PROGRAM="/sbin/scsi_id", RESULT="OEM 0815", NAME="disk1"
# USB printer to be called lp_color
-LABEL, BUS="usb", SYSFS_serial="W09090207101241330", NAME="lp_color"
+BUS="usb", SYSFS_serial="W09090207101241330", NAME="lp_color"
# SCSI disk with a specific vendor and model number is to be called boot
-LABEL, BUS="scsi", SYSFS_vendor="IBM", SYSFS_model="ST336", NAME="boot%n"
+BUS="scsi", SYSFS_vendor="IBM", SYSFS_model="ST336", NAME="boot%n"
# sound card with PCI bus id 00:0b.0 to be called dsp
-NUMBER, BUS="pci", ID="00:0b.0", NAME="dsp"
+BUS="pci", ID="00:0b.0", NAME="dsp"
# USB mouse at third port of the second hub to be called mouse1
-TOPOLOGY, BUS="usb", PLACE="2.3", NAME="mouse1"
+BUS="usb", PLACE="2.3", NAME="mouse1"
# ttyUSB1 should always be called pda with two additional symlinks
-REPLACE, KERNEL="ttyUSB1", NAME="pda", SYMLINK="palmtop handheld"
+KERNEL="ttyUSB1", NAME="pda", SYMLINK="palmtop handheld"
# multiple USB webcams with symlinks to be called webcam0, webcam1, ...
-LABEL, BUS="usb", SYSFS_model="XV3", NAME="video%n", SYMLINK="webcam%n"
+BUS="usb", SYSFS_model="XV3", NAME="video%n", SYMLINK="webcam%n"
.fi
.P
Permissions and ownership for the created device files may specified at
~ianmdlvl / elogind.git / blobdiff