X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udev.8;h=8ebcf7bd997e4c66bda8ea4fb3d524dec41246a0;hp=d7999aadfd182a686e3c17a063c52530e1bdc8e6;hb=3e16482d259c4a768b24a82bc0ed0e3a77954210;hpb=167a27e70f4010fdce561cff2ea1a07730aae28a diff --git a/udev.8 b/udev.8 index d7999aadf..8ebcf7bd9 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: +.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 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 contaning only the files for +actually present devices. .P As part of the .B hotplug @@ -18,7 +41,7 @@ On device creation, .B udev reads the sysfs directory of the given device to collect device attributes like label, serial number or bus device number. -These attributes may used as keys to determine a +These attributes may be used as keys to determine a unique name for device file creation. .B udev maintains a database for devices present on the system. @@ -30,27 +53,27 @@ queries its database for the name of the device file to be deleted. All .B udev configuration files consist of a set of lines of text. All empty -lines, and lines beginning with a '#' will be ignored. +lines and lines beginning with a '#' will be ignored. .P .B udev expects its main configuration file at .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: +The file consists of a set of variables and values allowing the user to +override default udev values. The following variables can be overridden +in this file: .TP .B udev_root -This is the where in the filesystem to place the device nodes. The default -value for this is +Indicates where to place the device nodes in the filesystem. The default +value is .IR /udev/ . .TP .B udev_db -The name and location of the udev database. The default value for this is +The name and location of the udev database. The default value is .IR /udev/.udev.tdb . .TP .B udev_rules -This is the location of the udev rules file. The default value for this is +This is the location of the udev rules file. The default value for this is .IR /etc/udev/udev.rules . If a directory is specified, the whole directory is scanned for files ending with @@ -66,32 +89,32 @@ 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 +removed. The default value 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 +This is the default mode for all nodes not explicitely matching in the +permissions file. The default value is .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 +This is the default owner for all nodes not explicitely matching in the +permissions file. The default value 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 +This is the default group for all nodes not explicitely matching in the +permissions file. The default value is .IR root . .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 - where to place the device nodes in the filesystem udev_root="/udev/" -# udev_db - The name and location of the udev database. +# udev_db - The name and location of the udev database udev_db="/udev/.udev.tdb" # udev_rules - The location of the directory where to look for files @@ -104,22 +127,22 @@ 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 - set the default mode for all nodes not +# explicitely matching 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 - set the default owner for all nodes not +# explicitely matching 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 - set the default group for all nodes not +# explicitely matching in the permissions file default_group="root" .fi .P -The rules for udev to use when naming devices may specified at +The rules for udev to use when naming devices may specified in .I /etc/udev/udev.rules -or specified by the +or by the .I udev_rules value in the .I /etc/udev/udev.conf @@ -128,16 +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 fields are: .TP .B BUS Match the bus type of the device. @@ -155,34 +177,56 @@ Match the topological position on bus, like physical port of USB device .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. +all of the values being required to match the rule. +.br +Trailing whitespace characters in the sysfs attribute value are ignored, if +the key doesn't have any trailing whitespace characters by itself. .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 +The environment variables of +.B udev +are also available for the program. +.br +The string returned by the program may be 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 +call. This key may be 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. +.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. +.br +If both the name and the symlink fields are omitted or its +values empty, the device will be ignored and no node will be created. +.br +If only the symlink field is given and the name field is omitted, +the rule will not be applied immediatly, but the symlink field is added +to the symlink list of the rule which will create the node. +This makes it possible to specify additional symlinks in a possibly +separate rules file, while the device nodes are maintained by the +distribution provided rules file. .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. @@ -197,22 +241,25 @@ The kernel minor number for the device. The bus id for the device. .TP .B %c -The +The string returned from the execution of .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: +A single part of the string, separated by a space character +may 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 %% -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 @@ -223,7 +270,7 @@ 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" -# SCSI disk with a specific vendor and model number is to be called boot +# SCSI disk with a specific vendor and model number will be called boot BUS="scsi", SYSFS{vendor}="IBM", SYSFS{model}="ST336", NAME="boot%n" # sound card with PCI bus id 00:0b.0 to be called dsp @@ -239,9 +286,9 @@ KERNEL="ttyUSB1", NAME="pda", SYMLINK="palmtop handheld" BUS="usb", SYSFS{model}="XV3", NAME="video%n", SYMLINK="webcam%n" .fi .P -Permissions and ownership for the created device files may specified at +Permissions and ownership for the created device files may specified in .I /etc/udev/udev.permissions -or specified by the +or by the .I udev_permission value in the .I /etc/udev/udev.conf @@ -261,6 +308,17 @@ video*:root:video:0660 dsp1:::0666 .fi .P +The value +.I $local +can be used instead of 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 @@ -273,9 +331,9 @@ 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 -following the '[' is a '!' then any character not enclosed is matched. +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 character not enclosed is matched. .SH "FILES" .nf /sbin/udev udev program @@ -285,10 +343,11 @@ 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