X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udev.8;h=680587a270c2d829a862a4bbe40bdce9ada58e3c;hp=9a597276c6fd00165c431523ca779bcb31f3733a;hb=42e4b6819ff91725fc101e1169e30ed27a7da3ca;hpb=765cbd97599d943adc73d03f4c91bd7cf7ef7fab diff --git a/udev.8 b/udev.8 index 9a597276c..680587a27 100644 --- a/udev.8 +++ b/udev.8 @@ -3,14 +3,45 @@ 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: +.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 continue, regardless of the state of the device representation. +.TP +.B UDEV_NO_DEVD +The default behavior of +.B udev +is to execute programs in the +.I /etc/dev.d/ +directory after device handling. If set, +.B udev +will skip this step. .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. +provides a dynamic device directory containing only the files for actually +present devices. It creates or removes device node files usually located in +the /dev directory, or it renames network interfaces. +.br + .P As part of the .B hotplug @@ -21,144 +52,125 @@ 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 -unique name for device file creation. +These attributes may be used as keys to determine a +unique name for the device. .B udev maintains a database for devices present on the system. .br 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 " , " group " or " path. -.TP -.BI -p " sysfs_path" -Specify the sysfs path of the device to query. -.TP -.BI -n " name" -Specify the name of the node for the device to query. -.TP -.B -d -Dump the whole database. -.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. +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: +.IR /etc/udev/udev.conf . +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 -.I /udev/ +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 -.I /udev/.udev.tdb +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 -.I /etc/udev/udev.rules +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 +.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 device handled. +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 -.I 0666 +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 -.I root +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 -.I root +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 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" -# default_mode - set the default mode for all nodes that have no -# explicit match in the permissions file +# udev_log - set to "yes" if you want logging, else "no" +udev_log="yes" + +# 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 file. .P 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 device name. One or 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 to name the device file or the network interface. .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 of 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. @@ -173,30 +185,64 @@ Match the device number on the bus, like PCI bus id. .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. +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. +.TP +.B NAME +The name of the node to be created, or the name, the network interface +should be renamed to. +.br +If given with the attribute +.BR NAME{ all_partitions } +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. +.TP +.B OWNER, GROUP, MODE +The permissions for this device. Every specified value overwrites the value +given in the permissions 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. @@ -211,15 +257,28 @@ 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 a space character +may be selected by specifying the part number as an attribute: +.BI %c{ N } +If the number is followed by the + char this part plus +all remaining parts of the result string are substituted: +.BI %c{ N+ } +.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 @@ -228,10 +287,10 @@ The '%' char itself. 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" +# 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 BUS="pci", ID="00:0b.0", NAME="dsp" @@ -243,12 +302,12 @@ BUS="usb", PLACE="2.3", NAME="mouse1" 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 +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 @@ -257,11 +316,6 @@ 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 @@ -273,6 +327,17 @@ video*:root:video:0660 dsp1:::0666 .fi .P +The value +.I $local +can be used instead of a specific username. In that case, udev will determine +the current local user at the time of device node creation and substitute +that username as the owner of the new device node. This is useful, for +example, to let hot-plugged devices, such as cameras, be owned by the user at +the current console. Note that if no user is currently logged in, or if udev +otherwise fails to determine a current user, the +.I default_owner +value is used in lieu. +.P A number of different fields in the above configuration files support a simple form of shell style pattern matching. It supports the following pattern characters: .TP @@ -285,21 +350,45 @@ Matches any single character, but does not match zero characters. .B [ ] Matches any single character specified within the brackets. For example, the pattern string "tty[SR]" would match either "ttyS" or "ttyR". Ranges are also -supported within this match with the '-' character. For example, to match on -the range of all digits, the pattern [0-9] would be used. If the first character -following the '[' is a '!' then any character not enclosed is matched. +supported within this match with the '\-' character. For example, to match on +the range of all digits, the pattern [0\-9] would be used. If the first character +following the '[' is a '!', any character not enclosed is matched. +.P +After device node creation, removal, or network device renaming, +.B udev +executes the programs in the directory tree under +.IR /etc/dev.d/ . +The name of a program must end with +.I .dev +suffix, to be recognized. +.br +In addition to the hotplug environment variables, +.B DEVNAME +is exported to make the name of the created node, or the name the network +device is renamed to, available to the executed program. The programs in every +directory are sorted in lexical order, while the directories are searched in +the following order: +.sp +.nf +/etc/dev.d/$(DEVNAME)/*.dev +/etc/dev.d/$(SUBSYSTEM)/*.dev +/etc/dev.d/default/*.dev +.fi .SH "FILES" .nf /sbin/udev udev program /etc/udev/* udev config files /etc/hotplug.d/default/udev.hotplug hotplug symlink to udev program +/etc/dev.d/* programs invoked by udev .fi .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