X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udev.8;h=3eb4aecad27b8adbbe3f92f1709d214cb867b10c;hp=771ecfa454915c2fd3b4eb13478837ff853923f9;hb=f1db055ab2e349ce22254562faaece66d6a4a873;hpb=d3db5e5e405b81ae094a5b0fab53d37b2356514c diff --git a/udev.8 b/udev.8 index 771ecfa45..3eb4aecad 100644 --- a/udev.8 +++ b/udev.8 @@ -2,81 +2,285 @@ .SH NAME udev \- Linux configurable dynamic device naming support .SH SYNOPSIS +.BI udev " hotplug-subsystem" +.br .B udev +.RI "[-q " sysfs_path "] [-rVh]" .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. +.P As part of the .B hotplug subsystem, .B udev -is exectuted if a kernel device is added or removed from the system. -.P +is executed if a kernel device is added or removed from the system. On device creation, .B udev -reads the sysfs directory of the given device, to collect device attributes +reads the sysfs directory of the given device to collect device attributes like label, serial number or bus device number. -These attributes are passed as a key to the namedev subsystem -to receive a unique name for device file creation. -namedev maintains a database for devices present on the system. -.P +These attributes are treated as a key +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 namedev database for the name of the device file to delete. +queries the internal 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. +.TP +.BI -q " sysfs_path" +Query with the sysfs path as argument for the name of the created device node. +.TP +.B -h +Print help text. +.SH "CONFIGURATION" +All +.B udev +configuration files consist of a set of lines of text. All empty +lines, and lines beginning with a '#' will be ignored. +.P + +.B udev +expects its main configuration file at +.I /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: +.TP +.B udev_root +This is the where in the filesystem to place the device nodes. The default +value for this is +.I /udev/ +.TP +.B udev_db +The name and location of the udev database. The default value for this is +.I /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 +.TP +.B udev_permissions +This is the location of the udev permission file. The default value for this is +.I /etc/udev/udev.permissions +.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 +.br +.P +.RI "A sample " udev.conf " might look like this: +.sp +.nf +# udev_root - where in the filesystem to place the device nodes +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_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 +# explicit match in the permissions file +default_mode="0666" +.fi +.P +The rules for udev to use when naming devices may specified at +.I /etc/udev/udev.rules +or specified by the +.I udev_rules +value in the +.I /etc/udev/udev.conf +file. .P -namedev expects its configuration at -.I /etc/udev/namedev.config. -The file consists of a set of lines. All empty lines and -lines beginning with a '#' will be ignored. +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. .br -Every line defines the mapping between device attributes and the name of -the device file. It starts with a keyword defining the method for -overriding the default kernel naming scheme, followed by a list -of keys and ends with the definition of the filename for the device. +If no matching configuration is found, the default kernel device name +is used. +.P +The line format is: +.sp +.I method, key,[key,...] name [, symlink] +.sp +where valid methods with corresponding keys are: +.TP +.B CALLOUT +calling external program, that returns a string to match. The +.B BUS +key is optional, but if specified, the sysfs device bus must be able to be +determined by a "device" symlink. +.br +.RB "keys: " BUS ", " PROGRAM ", " ID .TP .B LABEL device label or serial number, like USB serial number, SCSI UUID or -file system label +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. The +.B 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 ", " SYSFS_ .TP .B NUMBER device number on the bus, like PCI bus id +.br +.RB "keys: " BUS ", " ID .TP .B TOPOLOGY device position on bus, like physical port of USB device +.br +.RB "keys: " BUS ", " PLACE .TP .B REPLACE string replacement of the kernel device name +.br +.RB "key: " KERNEL +.TP +.B IGNORE +tell udev to not care about creation of this device, e.g. because the +device is already handled by another program +.br +.RB "key: " KERNEL +.P +The methods are applied in the following order: +.BR IGNORE ", " CALLOUT ", " LABEL ", " NUMBER ", " TOPOLOGY ", " REPLACE "." +.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' +.TP +.B %k +The "kernel name" for the device. +.TP +.B %M +The kernel major number for the device. +.TP +.B %m +The kernel minor number for the device. +.TP +.B %b +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.) +.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'. .P -If no matching configuration is found, the default kernel device name is used. -.SH "EXAMPLE" +.RI "A sample " udev.rules " might look like this:" +.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" + # USB printer to be called lp_color -LABEL, BUS="usb", serial="W09090207101241330", NAME="lp_color" +LABEL, 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" # sound card with PCI bus id 00:0b.0 to be called dsp -NUMBER, BUS="pci", id="00:0b.0", NAME="dsp" +NUMBER, 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" +TOPOLOGY, BUS="usb", PLACE="2.3", NAME="mouse1" -# ttyUSB1 should always be called pda -REPLACE, KERNEL="ttyUSB1", NAME="pda" +# ttyUSB1 should always be called pda with two additional symlinks +REPLACE, 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" +.fi +.P +Permissions and ownership for the created device files may specified at +.I /etc/udev/udev.permissions +or specified by the +.I udev_permission +value in the +.I /etc/udev/udev.conf +file. +.br +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 +.nf +#name:user:group:mode +input/*:root:root:644 +ttyUSB1:0:8:0660 +video*:root:video:0660 +dsp1:::0666 .fi +.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 +.B * +Matches zero, one, or more characters. +.TP +.B ? +Matches any single character, but does not match zero characters. +.TP +.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 +following the '[' is a '!' then any character not enclosed is matched. .SH "FILES" .nf -.ft B -.ft /sbin/udev udev program -/etc/udev/* udev config and database files +/etc/udev/* udev config files /etc/hotplug.d/default/udev.hotplug hotplug symlink to udev program .fi .LP .SH "SEE ALSO" -.B hotplug (8) +.BR hotplug (8) .PP The .I http://linux-hotplug.sourceforge.net/ web site. .SH AUTHORS -udev was developed by Greg Kroah-Hartman with much help from -Dan Stekloff and many others. +.B udev +was developed by Greg Kroah-Hartman with much help from +Dan Stekloff , Kay Sievers , and +many others.