X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udev.8;h=c0dc68b80360a2454a882ec319d2c255dde03a87;hp=603ca45cbac74a9e5afb0bedd9489d056b85cbfe;hb=c58f8c3000b99db5c3810b9f8b1ecc2044070ac1;hpb=ad63031e49abc18a961c4b4302312744a487f417

diff --git a/udev.8 b/udev.8
index 603ca45cb..c0dc68b80 100644
--- a/udev.8
+++ b/udev.8
@@ -3,11 +3,34 @@
 udev \- Linux configurable dynamic device naming support
 .SH SYNOPSIS
 .BI udev " hotplug-subsystem"
+.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
+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
@@ -35,7 +58,7 @@ lines, and lines beginning with a '#' will be ignored.
 
 .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:
@@ -43,39 +66,46 @@ 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
-.I yes
+.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
-.I root
+.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
-.I root
+.IR root .
 .br
 .P
 .RI "A sample " udev.conf " might look like this:
@@ -87,8 +117,9 @@ udev_root="/udev/"
 # 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"
@@ -120,16 +151,15 @@ file.
 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.
+and the name is used for the device node.
 .br
 If no matching rule is found, the default kernel device name is used.
 .P
-The line format is:
+Every rule consists of a list a comma separated fields:
 .sp
-.I key,[key,...] name [, symlink]
+.IR "key " ,[ "key " ,...] " name " [, " symlink" ]
 .sp
-where keys are:
+where possible fields are:
 .TP
 .B BUS
 Match the bus type of the device.
@@ -151,6 +181,10 @@ 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 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.
@@ -161,20 +195,26 @@ Match the returned string of the last
 call. This key may used in any following rule after a
 .B PROGRAM
 call.
-.P
-The
+.TP
 .B NAME
-field given with the attribute
+The name of the node to be created. If the name field is omitted or its
+value is empty, the device will be ignored and no node will be created.
+.br
+If given with the attribute
 .BR NAME{ all_partitions }
-will  create all 15 partitions of a blockdevice.
+it will  create all 15 partitions of a blockdevice.
 This may be useful for removable media devices.
+.TP
+.B SYMLINK
+The name of a symlink targeting the node. Multiple symlinks may be
+specified by separating the names by the space character.
 .P
 .RB "The " NAME " ," SYMLINK " and " PROGRAM
 fields support simple printf-like string substitution:
 .TP
 .B %n
 The "kernel number" of the device.
-for example, 'sda3' has a "kernel number" of '3'
+For example, 'sda3' has a "kernel number" of '3'.
 .TP
 .B %k
 The "kernel name" for the device.
@@ -204,7 +244,11 @@ my be selected by specifying the part number as a attribute:
 The content of a sysfs attribute.
 .TP
 .B %%
-The '%' char itself.
+The '%' character itself.
+.P
+The count of charcters to insert may be limited by specifying
+the format length value. For example, '%3s{file}' will only insert
+the first three characters of the sysfs attribute.
 .P
 .RI "A sample " udev.rules " might look like this:"
 .sp
@@ -242,11 +286,6 @@ file.
 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
@@ -258,6 +297,17 @@ video*:root:video:0660
 dsp1:::0666
 .fi
 .P
+The value
+.I $local
+can be substituted for a specific username.  In that case, udev will determine
+the current local user at the time of device node creation and substitute
+that username as the owner of the new device node.  This is useful, for
+example, to let hot-plugged devices, such as cameras, be owned by the user at
+the current console.  Note that if no user is currently logged in, or if udev
+otherwise fails to determine a current user, the
+.I default_owner
+value is used in lieu.
+.P
 A number of different fields in the above configuration files support a simple
 form of shell style pattern matching. It supports the following pattern characters:
 .TP
@@ -270,8 +320,8 @@ Matches any single character, but does not match zero characters.
 .B [ ]
 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
+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 '!' then any character not enclosed is matched.
 .SH "FILES"
 .nf
@@ -282,10 +332,11 @@ following the '[' is a '!' then any character not enclosed is matched.
 .LP
 .SH "SEE ALSO"
 .BR udevinfo (8),
+.BR udevd (8),
 .BR hotplug (8)
 .PP
 The
-.I http://linux-hotplug.sourceforge.net/
+.I http://linux\-hotplug.sourceforge.net/
 web site.
 .SH AUTHORS
 .B udev