X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=docs%2Fudev.xml;h=e0542a6be199048f024550dd784835bb17a47a6a;hp=02dcd2586a8173939d55f0341a8bc9e74f6d195d;hb=864412e02df16555c02da9ccb0a67fddb6628acd;hpb=7b86ada7d4a6b2597299912964d1b8da3d059691 diff --git a/docs/udev.xml b/docs/udev.xml index 02dcd2586..e0542a6be 100644 --- a/docs/udev.xml +++ b/docs/udev.xml @@ -27,7 +27,7 @@ udev - 8 + 7 @@ -42,9 +42,7 @@ Usually udev runs as udevd 8 and receives uevents directly from the - kernel if a device is added or removed form the system. The program - udev itself may be used as an event handler in situations, - where running the daemon is not appropriate, like in initramfs. + kernel if a device is added or removed form the system. If udev receives a device event, it matches its configured rules against the available device attributes provided in sysfs to identify the device. @@ -55,7 +53,7 @@ CONFIGURATION All udev configuration files are placed in /etc/udev/*. - Every file consist of a set of lines of text. All empty lines or lines beginning + Every file consists of a set of lines of text. All empty lines or lines beginning with '#' will be ignored. Configuration file @@ -71,14 +69,6 @@ - - - - The name and location of the udev database. The default value is - /dev/.udevdb. - - - @@ -158,66 +148,68 @@ - Match the kernel action name. + Match the name of the event action. - Match the kernel device name + Match the name of the device. - Match the kernel devpath. + Match the devpath of the device. - Match the kernel subsystem name + Match the subsystem of the device. - Match the typ of bus the device is connected to. + Search the devpath upwards for a matching device subsystem name. - Match the kernel driver name. + Search the devpath upwards for a matching device driver name. - Match the device number on the bus. + Search the devpath upwards for a matching device name. - + - Match against the value of an environment key. Depending on - the specified operation, this key is also used as a assignment. + Search the devpath upwards for a device with matching sysfs attribute values. + Up to five keys can be specified per rule. All attributes + must match on the same device. Trailing whitespace in the attribute values is ignored, + if the specified match value does not contain trailing whitespace itself. - + - Match the sysfs attribute value. Up to five values can be specified. - Trailing whitespace is ignored, if the specified match value does not contain - trailing whitespace itself. + Match against the value of an environment variable. Up to five + keys can be specified per rule. This key can also be used to export a variable to + the environment. @@ -273,8 +265,8 @@ - The name of the node to be created, or the name, the network interface - should be renamed to. Only one rule can set the a name, all later rules with + The name of the node to be created, or the name the network interface + should be renamed to. Only one rule can set the node name, all later rules with a NAME key will be ignored. @@ -292,7 +284,7 @@ - The permissions for the device node. Every specified value over writes + The permissions for the device node. Every specified value overwrites the compiled-in default value. @@ -300,8 +292,8 @@ - Export the key to the environment. Depending on the specified - operation, this key is also used as a match. + Export a variable to the environment. This key can also be used to match + against an environment variable. @@ -330,7 +322,7 @@ - Import the printed result or the content of a file in environment key + Import the printed result or the value of a file in environment key format into the event environment. will execute an external program and read its output. will inport a text file. If no option is given, udev will determine it from the executable @@ -341,8 +333,8 @@ - Wait for the specified sysfs file of the device to be created. May be used - to fight agains timing issues wth the kernel. + Wait for the specified sysfs file of the device to be created. Can be used + to fight against kernel sysfs timing issues. @@ -361,68 +353,74 @@ The , , , - and fields support simple - printf-like string substitutions: + , 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 the complete environment set by earlier matching + rules. For all other fields, substitutions are applied while the individual rule is + being processed. The available substitutions are: - , + , The kernel name for this device. - , + , - The kernel bus id for this device. + The kernel number for this device. For example, 'sda3' has + kernel number of '3' - , + , - The kernel number for this device. For example, 'sda3' has - kernel number of '3' + The devpath of the device. - , + , - The devpath of the device. + The name of the device matched while searching the devpath upwards for + , and . + - , + , - The content of a sysfs attribute. + The value of a sysfs attribute found at the current or a parent device. - , + , The value of an environment variable. - , + , The kernel major number for the device. - + The kernel minor number for the device. - , + , The string returned by the external program requested with PROGRAM. A single part of the string, separated by a space character may be selected @@ -433,33 +431,21 @@ - , - - If a device node already exists with the name, the smallest next free - number is used. This can be used to create compatibility symlinks and enumerate - devices of the same type originating from different kernel subsystems. - Note: The use of the enumeration facility is unreliable for events that - request a number at the same time. The use of enumerations in todays setups - where devices can come and go at any time is not recomended. - - - - - , + , The node name of the parent device. - , + , The udev_root value. - , + , The name of a created temporary device node to provide access to the device from a external program before the real node is created. @@ -528,14 +514,11 @@ SEE ALSO - udev8 + udevd8 , udevinfo8 , - - udevd8 - , udevmonitor8