Editing Devd.conf

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==Introduction==





The devd utility is a system daemon that runs in the background all the time.  Whenever a device is added to or removed from the device tree,   devd will execute actions specified in [https://www.freebsd.org/cgi/man.cgi?query=devd.conf&apropos=0&sektion=0&manpath=FreeBSD+12.1-RELEASE+and+Ports&arch=default&format=html devd.conf(5)].  For example,	devd  might execute [https://www.freebsd.org/cgi/man.cgi?query=dhclient&sektion=8&apropos=0&manpath=FreeBSD+12.1-RELEASE+and+Ports dhclient(8)] when an Ethernet	adapter	is added to the	system, and kill the [https://www.freebsd.org/cgi/man.cgi?query=dhclient&sektion=8&apropos=0&manpath=FreeBSD+12.1-RELEASE+and+Ports dhclient(8)] instance when the same adapter is removed.<br/>
Another example would be for devd to use a	table to locate	and load via [https://www.freebsd.org/cgi/man.cgi?query=kldload&sektion=8&apropos=0&manpath=FreeBSD+12.1-RELEASE+and+Ports kldload(8)] the proper driver for an unrecognized device that is added to  the system.

The devd utility hooks into the [https://www.freebsd.org/cgi/man.cgi?query=devctl&sektion=4&apropos=0&manpath=FreeBSD+12.1-RELEASE+and+Ports devctl(4)] device driver.  This device  driver has	hooks into the device configuration system.  When nodes	are   added or deleted from the tree, this device will deliver information    about the event to	devd.  Once devd has parsed the	message, it will  search its	action list for	that kind of event and perform the action with  the highest matching value.  For most mundane uses, the default handlers   are adequate.  However, for more advanced users, the power	is present to    tweak every aspect	of what	happens.

The devd utility reads '''/etc/devd.conf''' or the alternate configuration file  specified with a -f option	and uses that file to drive the	rest of	the    process.  While the format	of this	file is	described in [https://www.freebsd.org/cgi/man.cgi?query=devd.conf&apropos=0&sektion=0&manpath=FreeBSD+12.1-RELEASE+and+Ports&arch=default&format=html devd.conf(5)], some basics are covered here.  In the options section, one	can define
multiple directories to search for	config files.  All files in these directories whose names match the pattern *.conf are	parsed.	 These files are intended to be	installed by third party vendors that wish to hook  into the devd system without modifying the	user's other config files.

Since [https://www.freebsd.org/cgi/man.cgi?query=devctl&sektion=4&apropos=0&manpath=FreeBSD+12.1-RELEASE+and+Ports devctl(4)] allows only one active reader, devd multiplexes it, forwarding all events	to any number of connected clients.  Clients connect    by	opening	the SOCK_SEQPACKET UNIX	domain socket at  '''/var/run/devd.seqpacket.pipe'''.

==The Configuration File devd.conf==

A [https://www.freebsd.org/cgi/man.cgi?query=devd&sektion=8&apropos=0&manpath=FreeBSD+12.1-RELEASE+and+Ports 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:
{|class="wikitable" style="width:96.5%;background:#FFFFFF; border:2px solid #008000;text-align:left;padding: 10px" 
|-
! scope="col" style="width: 100px;"|'''Name'''
! scope="col" style="width: 350px;"|'''Description'''
|-
|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  [https://www.freebsd.org/cgi/man.cgi?query=devd&sektion=8&apropos=0&manpath=FreeBSD+12.1-RELEASE+and+Ports  devd(8)].
|}

==More Information==

For more information read 
* [https://www.freebsd.org/cgi/man.cgi?query=devd.conf&apropos=0&sektion=0&manpath=FreeBSD+12.1-RELEASE+and+Ports&arch=default&format=html the man page]
* [https://github.com/OpenRC/openrc/blob/72df51e17ba0e1a0f94451b4bbfb338288c4625c/etc/devd.conf on GitHub]

[[Category:Sysutils]]
@@ Line 4: / Line 4: @@
 ==Introduction==
-Refer to [https://www.freebsd.org/cgi/man.cgi?query=devd.conf&apropos=0&sektion=0&manpath=FreeBSD+12.1-RELEASE+and+Ports&arch=default&format=html devd.conf(5)] and [https://www.freebsd.org/cgi/man.cgi?query=devd&sektion=8&apropos=0&manpath=FreeBSD+12.1-RELEASE+and+Ports devd(8)] man pages for the details on how to run and configure devd.
-'''devd.conf ''' is the configuration	file for [https://www.freebsd.org/cgi/man.cgi?query=devd&sektion=8&apropos=0&manpath=FreeBSD+12.1-RELEASE+and+Ports devd(8)]
-==What is [https://www.freebsd.org/cgi/man.cgi?query=devd&sektion=8&apropos=0&manpath=FreeBSD+12.1-RELEASE+and+Ports devd(8)]==
-The devd daemon provides a way to have userland programs run when certain  kernel events happen.
 The devd utility is a system daemon that runs in the background all the time.  Whenever a device is added to or removed from the device tree,   devd will execute actions specified in [https://www.freebsd.org/cgi/man.cgi?query=devd.conf&apropos=0&sektion=0&manpath=FreeBSD+12.1-RELEASE+and+Ports&arch=default&format=html devd.conf(5)].  For example,	devd  might execute [https://www.freebsd.org/cgi/man.cgi?query=dhclient&sektion=8&apropos=0&manpath=FreeBSD+12.1-RELEASE+and+Ports dhclient(8)] when an Ethernet	adapter	is added to the	system, and kill the [https://www.freebsd.org/cgi/man.cgi?query=dhclient&sektion=8&apropos=0&manpath=FreeBSD+12.1-RELEASE+and+Ports dhclient(8)] instance when the same adapter is removed.<br/>