General Syntax

A devd(8) configuration consists of two general features, statements and comments. All statements end with a semicolon. Many statements can contain substatements, which are also terminated with a semicolon.

The following statements are supported:

attach

Specifies various matching criteria and actions to perform when a newly attached device matches said criteria.

detach

Specifies various matching criteria and actions to perform when a newly detached device matches said criteria.

nomatch

Specifies various matching criteria and actions to perform when no device driver currently loaded in the kernel claims a (new) device.

notify

Specifies various matching criteria and actions to perform when the kernel sends an event notification to userland.

options

Specifies various options and parameters for the operation of devd(8).

Statements may occur in any order in the configuration file, and may be repeated as often as required. Further details on the syntax and meaning of each statement and their substatements are explained below.

Each statement, except options has a priority (an arbitrary number) associated with it, where ‘0’ is defined as the lowest priority. If two statements match the same event, only the action of the statement with highest priority will be executed. In this way generic statements can be overridden for devices or notifications that require special attention.

The general syntax of a statement is:

statement priority {
	substatement "value";
	...
	substatement "value";
};

Sub-statements

The following sub-statements are supported within the options statement.

directory "/some/path";

Adds the given directory to the list of directories from which devd(8) will read all files named "*.conf" as further configuration files. Any number of directory statements can be used.

pid-file "/var/run/devd.pid";

Specifies PID file.

set regexp-name "(some|regexp)";

Creates a regular expression and assigns it to the variable regexp-name. The variable is available throughout the rest of the configuration file. If the string begins with ‘!’, it matches if the regular expression formed by the rest of the string does not match. All regular expressions have an implicit ‘^$’ around them.

The following sub-statements are supported within the attach and detach statements.

action "command";

Command to execute upon a successful match. Example “/etc/pccard_ether $device-name start”.

class "string";

This is shorthand for “match "class" "string"”.

device-name "string";

This is shorthand for “match "device-name" "string"”. This matches a device named string, which is allowed to be a regular expression or a variable previously created containing a regular expression. The “device-name” variable is available for later use with the action statement.

match "variable" "value";

Matches the content of value against variable; the content of value may be a regular expression. Not required during attach nor detach events since the device-name statement takes care of all device matching. For a partial list of variables, see below.

media-type "string";

For network devices, media-type will match devices that have the given media type. Valid media types are: “Ethernet”, “802.11”, and “ATM”.

subdevice "string";

This is shorthand for “match "subdevice" "string"”.

The following sub-statements are supported within the nomatch statement.

action "command";

Same as above.

match "variable" "value";

Matches the content of value against variable; the content of value may be a regular expression. For a partial list of variables, see below.

The following sub-statements are supported within the notify statement. The “notify” variable is available inside this statement and contains, a value, depending on which system and subsystem that delivered the event.

action "command";

Command to execute upon a successful match. Example “/etc/rc.d/power_profile $notify”.

match "system | subsystem | type | notify" "value";

Any number of match statements can exist within a notify statement; value can be either a fixed string or a regular expression. Below is a list of available systems, subsystems, and types.

media-type "string";

See above.

Variables that can be used with the match statement

A partial list of variables and their possible values that can be used together with the match statement. The variables are published by the bus based on characteristics of the device that generated the event (for device events). Variables for other classes of events are dependent on those events.

Variable

Description

*

The entire message from the current event.

_

The entire message from the current event, after the initial type character.

timestamp

The time this event was processed, in seconds since 1970 dot fraction.

bus

Device name of parent bus.

cdev

Device node path if one is created by the devfs(5) filesystem.

class

Device class.

comm

Executable name (kernel).

core

Path to core file (kernel).

device

Device ID.

devclass

Device Class (USB).

devsubclass

Device Sub-class (USB).

device-name

Name of attached/detached device.

endpoints

Endpoint count (USB).

function

Card functions.

interface

Interface ID (USB).

intclass

Interface Class (USB).

intprotocol

Interface Protocol (USB).

intsubclass

Interface Sub-class (USB).

jail

Jail name for the process triggering the rule (RCTL).

mode

Peripheral mode (USB).

notify

Match the value of the “notify” variable.

parent

Parent device.

pid

PID of the process triggering the rule (RCTL).

port

Hub port number (USB).

product

Product ID (USB).

release

Hardware revision (USB).

ruid

Real UID of the process triggering the rule (RCTL).

rule

Rule (RCTL).

sernum

Serial Number (USB).

slot

Card slot.

subvendor

Sub-vendor ID (PCI).

subdevice

Sub-device ID (PCI).

subsystem

Matches a subsystem of a system, see below.

system

Matches a system type, see below.

type

Type of notification, see below.

vendor

Vendor ID.

Notify matching

A partial list of systems, subsystems, and types used within the notify mechanism.

A link state change to UP on the interface “fxp0” would result in the following notify event:

system=IFNET subsystem=fxp0 type=LINK_UP

An AC line state change to “offline” would result in the following event:

system=ACPI subsystem=ACAD notify=0x00

Comments

Comments may appear anywhere that whitespace may appear in a configuration file. To appeal to programmers of all kinds, they can be written in C, C++, or shell/Perl constructs.

C-style comments start with the two characters ‘/*’ (slash, star) and end with ‘*/’ (star, slash). Because they are completely delimited with these characters, they can be used to comment only a portion of a line or to span multiple lines.

C-style comments cannot be nested. For example, the following is not valid because the entire comment ends with the first ‘*/’:

/* This is the start of a comment.
   This is still part of the comment.
/* This is an incorrect attempt at nesting a comment. */
   This is no longer in any comment. */

C++-style comments start with the two characters ‘//’ (slash, slash) and continue to the end of the physical line. They cannot be continued across multiple physical lines; to have one logical comment span multiple lines, each line must use the ‘//’ pair. For example:

// This is the start of a comment.  The next line
// is a new comment, even though it is logically
// part of the previous comment.

Notes on Variable Expansion

To prevent issues with special shell characters, the following happens for each variable $foo.

1. The characters “$'” are inserted.
2. The string “$foo” is removed.
3. The value of the foo variable is inserted into the buffer with all single quote characters prefixed by a backslash.

See sh(1) for what this construct means. It is safe in all context, except one: inside single quotes. If foo=meta and bar=var, then a rule like the following:

action "echo '$foo $bar'";

echo '$'meta' $'var''

$meta $var

The above should be written as

action "echo $foo' '$bar"