X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udev%2Fudev.xml;h=fca0dad7bff1956c8324e8dd75053ace61bb5d38;hp=78b538bd4a2d333c8957ac61d15c08d99335b960;hb=220893b3cbdbf8932f95c44811b169a8f0d33939;hpb=401e59e9aefdda48d037e8d5026c2c8e1edec96e diff --git a/udev/udev.xml b/udev/udev.xml index 78b538bd4..fca0dad7b 100644 --- a/udev/udev.xml +++ b/udev/udev.xml @@ -41,8 +41,8 @@ Configuration - udev configuration files are placed in /etc/udev/ - and /lib/udev/. All empty lines or lines beginning with + udev configuration files are placed in /etc/udev + and /usr/lib/udev. All empty lines or lines beginning with '#' are ignored. Configuration file @@ -71,14 +71,18 @@ Rules files The udev rules are read from the files located in the - default rules directory /lib/udev/rules.d/, - the custom rules directory /etc/udev/rules.d/ - and the temporary rules directory /run/udev/rules.d/. - All rule files are collectively sorted and processed in lexical order, - regardless of the directories in which they live. However, files in - /etc/udev/rules.d/ take precedence over files with - the same name in /lib/udev/rules.d/; this can be - used to ignore a default rules file if needed. + system rules directory /usr/lib/udev/rules.d, + the local administration directory /etc/udev/rules.d + and the volatile runtime directory /run/udev/rules.d. + All rules files are collectively sorted and processed in lexical order, + regardless of the directories in which they live. However, files with + identical file names replace each other. Files in /run + have the highest priority, files in /etc take precedence + over files with the same name in /lib. This can be + used to overwrite a system rules file if needed; a symlink in + /etc with the same name as a rules file in + /lib, pointing to /dev/null, + disables the rules file entirely. Rule files must have the extension .rules; other extensions are ignored. @@ -163,9 +167,8 @@ - Match the name of the node or network interface. It can - be used once the NAME key has been set in one of the preceding - rules. + Match the name of a network interface. It can be used once the + NAME key has been set in one of the preceding rules. @@ -233,6 +236,13 @@ + + + + Search the devpath upwards for a device with matching tag. + + + @@ -281,7 +291,7 @@ - Matches zero, or any number of characters. + Matches zero or more characters. @@ -295,8 +305,8 @@ 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 + Ranges are also supported via the '-' character. + For example, to match on the range of all digits, the pattern [0-9] could be used. If the first character following the '[' is a '!', any characters not enclosed are matched. @@ -308,17 +318,8 @@ - The name, a network interface should be renamed to. Or as - a temporary workaround, the name a device node should be named. - Usually the kernel provides the defined node name, or even creates - and removes the node before udev even receives any event. Changing - the node name from the kernel's default creates inconsistencies - and is not supported. If the kernel and NAME specify different names, - an error is logged. Udev is only expected to handle device node - permissions and to create additional symlinks, not to change - kernel-provided device node names. Instead of renaming a device node, - SYMLINK should be used. Symlink names must never conflict with - device node names, it results in unpredictable behavior. + The name to use for a network interface. The name of a device node + can not be changed by udev, only additional symlinks can be created. @@ -331,10 +332,10 @@ devices claim the same name, the link always points to the device with the highest link_priority. If the current device goes away, the links are re-evaluated and the device with the next highest link_priority becomes the owner of - the link. If no link_priority is specified, the order of the devices, and - which one of them owns the link, is undefined. Claiming the same name for - a symlink, which is or might be used for a device node, may result in - unexpected behavior and is not supported. + the link. If no link_priority is specified, the order of the devices (and + which one of them owns the link) is undefined. Also, symlink names must + never conflict with the kernel's default device node names, as that would + result in unpredictable behavior. @@ -359,7 +360,8 @@ Set a device property value. Property names with a leading '.' - are not stored in the database or exported to external tool or events. + are neither stored in the database nor exported to events or + external tools (run by, say, the PROGRAM match key). @@ -385,23 +387,25 @@ this or a dependent device. Long running tasks need to be immediately detached from the event process itself. If no absolute path is given, the program is expected to live in - /lib/udev, otherwise the absolute path must be - specified. Program name and arguments are separated by spaces. Single quotes - can be used to specify arguments with spaces. + the directory provided at compile-time to configure via --libexecdir + (this is usually /usr/lib/udev), otherwise the absolute + path must be specified. The program name and following arguments are + separated by spaces. Single quotes can be used to specify arguments with + spaces. - Named label where a GOTO can jump to. + A named label to which a GOTO may jump. - Jumps to the next LABEL with a matching name + Jumps to the next LABEL with a matching name. @@ -423,8 +427,8 @@ - Import a text file specified as the assigned value, which must be in - environment key format. + Import a text file specified as the assigned value, the content + of which must be in environment key format. @@ -438,7 +442,7 @@ - Import a single property from the kernel commandline. For simple flags + Import a single property from the kernel command line. For simple flags the value of the property is set to '1'. @@ -453,18 +457,15 @@ - If no option is given, udev chooses between - and based on the executable bit of the file - permissions. - Wait for a file to become available or until a 10 - seconds timeout expires. The path is relative to the sysfs device, - i. e. if no path is specified this waits for an attribute to appear. + Wait for a file to become available or until a timeout of + 10 seconds expires. The path is relative to the sysfs device; + if no path is specified, this waits for an attribute to appear. @@ -498,9 +499,9 @@ - Apply the permissions specified in this rule to a static device node with + Apply the permissions specified in this rule to the static device node with the specified name. Static device nodes might be provided by kernel modules - or copied from /lib/udev/devices. These nodes might not have + or copied from /usr/lib/udev/devices. These nodes might not have a corresponding kernel device at the time udevd is started; they can trigger automatic kernel module loading. @@ -508,8 +509,8 @@ - Watch the device node with inotify; when closed after being opened for - writing, a change uevent is synthesised. + Watch the device node with inotify; when the node is closed after being opened for + writing, a change uevent is synthesized. @@ -525,10 +526,10 @@ The , , , , , and - fields support simple printf-like string substitutions. The - format chars gets applied after all rules have been processed, right before the program - is executed. It allows the use of device properties set by earlier matching - rules. For all other fields, substitutions are applied while the individual rule is + fields support simple string substitutions. The + substitutions are performed after all rules have been processed, right before the program + is executed, allowing for the use of device properties set by earlier matching + rules. For all other fields, substitutions are performed while the individual rule is being processed. The available substitutions are: @@ -577,9 +578,9 @@ The value of a sysfs attribute found at the device where all keys of the rule have matched. If the matching device does not have such an attribute, and a previous KERNELS, SUBSYSTEMS, DRIVERS, or - ATTRS test selected a parent device, use the attribute from that - parent device. - If the attribute is a symlink, the last element of the symlink target is + ATTRS test selected a parent device, then the attribute from that + parent device is used. + If the attribute is a symlink, the last element of the symlink target is returned as the value. @@ -609,9 +610,9 @@ , The string returned by the external program requested with PROGRAM. - A single part of the string, separated by a space character may be selected + A single part of the string, separated by a space character, may be selected by specifying the part number as an attribute: . - If the number is followed by the '+' char this part plus all remaining parts + If the number is followed by the '+' character, this part plus all remaining parts of the result string are substituted: @@ -626,7 +627,7 @@ - The current name of the device node. If not changed by a rule, it is the + The current name of the device. If not changed by a rule, it is the name of the kernel device. @@ -634,8 +635,8 @@ - The current list of symlinks, separated by a space character. The value is - only set if an earlier rule assigned a value, or during a remove events. + A space-separated list of the current symlinks. The value is + only set during a remove event or if an earlier rule assigned a value. @@ -654,10 +655,9 @@ - , + , - The name of a created temporary device node to provide access to - the device from a external program before the real node is created. + The name of the device node.