udev \- Linux configurable dynamic device naming support
.SH SYNOPSIS
.BI udev " hotplug-subsystem"
-.br
+.P
+The environment must provide the following variables:
+.TP
+.B ACTION
+.IR add " or " remove
+signifies the connection or disconnection of a device.
+.TP
+.B DEVPATH
+The sysfs devpath of the device without the mountpoint but a leading slash.
+.P
+Additional optional environment variables are:
+.TP
+.B UDEV_CONFIG_FILE
+Overrides the default location of the
.B udev
-.RI "[-q " query_type " -p " sysfs_path "] [-drVh]"
+config file.
+.TP
+.B UDEV_NO_SLEEP
+The default behavior of
+.B udev
+is to wait until all the sysfs files of the device chain are populated. If set
+.B udev
+will will continue, regardless of the state of the device representation.
.SH "DESCRIPTION"
.B udev
creates or removes device node files usually located in the /dev directory.
-Its goal is to provide a dynamic device directory that contains only the files
-for devices that are actually present.
+It provides a dynamic device directory that contains only the files for
+devices that are actually present.
.P
As part of the
.B hotplug
On device removal,
.B udev
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
.B udev
expects its main configuration file at
-.I /etc/udev/udev.conf.
+.IR /etc/udev/udev.conf .
The file consists of a set of variables and values that allow the user to
override default udev values. The current set of variables that can be
overridden in this file is:
.B udev_root
This is the where in the filesystem to place the device nodes. The default
value for this is
-.I /udev/
+.IR /udev/ .
.TP
.B udev_db
The name and location of the udev database. The default value for this is
-.I /udev/.udev.tdb
+.IR /udev/.udev.tdb .
.TP
.B udev_rules
This is the location of the udev rules file. The default value for this is
-.I /etc/udev/udev.rules
+.IR /etc/udev/udev.rules .
+If a directory is specified, the whole directory is
+scanned for files ending with
+.I .rules
+and all rule files are read in lexical order.
.TP
.B udev_permissions
-This is the location of the udev permission file. The default value for this is
-.I /etc/udev/udev.permissions
+This is the location of the udev permission file. The default value for this is
+.IR /etc/udev/udev.permissions .
+If a directory is specified, the whole directory is scanned for files ending with
+.I .permissions
+and all permission files are read in lexical order.
+.TP
+.B udev_log
+If you want udev to log some information to the syslog for every node created or
+removed. The default value for this is
+.IR yes .
.TP
.B default_mode
This is the default mode for all nodes that have no explicit match in the
permissions file. The default value for this is
-.I 0666
+.IR 0666 .
+.TP
+.B default_owner
+This is the default owner for all nodes that have no explicit match in the
+permissions file. The default value for this is
+.IR root .
+.TP
+.B default_group
+This is the default group for all nodes that have no explicit match in the
+permissions file. The default value for this is
+.IR root .
.br
.P
.RI "A sample " udev.conf " might look like this:
# udev_db - The name and location of the udev database.
udev_db="/udev/.udev.tdb"
-# udev_rules - The name and location of the udev rules file
-udev_rules="/etc/udev/udev.rules"
+# udev_rules - The location of the directory where to look for files
+ which names ending with .rules
+udev_rules="/etc/udev/"
# udev_permissions - The name and location of the udev permission file
udev_permissions="/etc/udev/udev.permissions"
+# udev_log - set to "yes" if you want logging, else "no"
+udev_log="yes"
+
# default_mode - set the default mode for all nodes that have no
# explicit match in the permissions file
default_mode="0666"
+
+# default_owner - set the default owner for all nodes that have no
+# explicit match in the permissions file
+default_owner="root"
+
+# default_group - set the default group for all nodes that have no
+# explicit match in the permissions file
+default_group="root"
.fi
.P
The rules for udev to use when naming devices may specified at
.B PLACE
Match the topological position on bus, like physical port of USB device
.TP
-.BI SYSFS_ filename
+.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.
+A few command line options may specified, but shell characters like pipe,
+diversion or similiar options are not available. The environment variables of
+.B udev
+are also available for the program.
+.br
The string returned by the program may additionally matched with the
.B RESULT
key.
.B PROGRAM
call.
.P
+The
+.B NAME
+field given with the attribute
+.BR NAME{ all_partitions }
+will create all 15 partitions of a blockdevice.
+This may be useful for removable media devices.
+.P
.RB "The " NAME " ," SYMLINK " and " PROGRAM
fields support simple printf-like string substitution:
.TP
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.)
+.br
+A single part of the string, separated by the space character
+my be selected by specifying the part number as a attribute:
+.BI %c{ part }
+.TP
+.BI %s{ filename }
+The content of a sysfs attribute.
.TP
-.B %D
-Use the devfs style disk name for this device.
-For partitions, this will result in 'part%n'
-If this is not a partition, it will result in 'disc'.
+.B %%
+The '%' char itself.
.P
.RI "A sample " udev.rules " might look like this:"
.sp
BUS="scsi", PROGRAM="/sbin/scsi_id", RESULT="OEM 0815", NAME="disk1"
# USB printer to be called lp_color
-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
-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
BUS="pci", ID="00:0b.0", NAME="dsp"
KERNEL="ttyUSB1", NAME="pda", SYMLINK="palmtop handheld"
# multiple USB webcams with symlinks to be called webcam0, webcam1, ...
-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
Every line lists a device name followed by owner, group and permission
mode. All values are separated by colons. The name field may contain a
pattern to apply the values to a whole class of devices.
-.br
-If
-.B udev
-was built using klibc or is used before the user database is accessible (e.g.
-.BR initrd "(4)), only numeric owner and group values may be used."
.sp
.RI "A sample " udev.permissions " might look like this:"
.sp
.fi
.LP
.SH "SEE ALSO"
+.BR udevinfo (8),
+.BR udevd (8),
.BR hotplug (8)
.PP
The
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