1.\" 2.\" Copyright (c) 2002 M. Warner Losh. 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd October 17, 2002 29.Dt DEVD 8 30.Os 31.Sh NAME 32.Nm devd 33.Nd "Device state change daemon" 34.Sh SYNOPSIS 35.Nm 36.Op Fl d 37.Sh DESCRIPTION 38The 39.Nm 40daemon provides a way to have userland programs run when certain 41kernel events happen. 42.Pp 43The following options are accepted. 44.Bl -tag -width indent 45.It Fl d 46Enable debugging messages and run in the foreground instead of 47becoming a daemon. 48.El 49.Sh IMPLEMENTATION NOTES 50.Nm 51is a system daemon that runs in the background all the time. 52Whenever a device is added to or removed from the device tree, 53.Nm 54will execute actions specified in 55.Xr devd.conf 5 . 56For example, 57.Nm 58might execute 59.Xr dhclient 8 60when an ethernet adapter is added to the system and kill the 61.Xr dhclient 8 62instance when the same adapter is removed. 63Another example would be for 64.Nm 65to use a table to locate and load via 66.Xr kldload 8 67the proper driver for an unrecognized device that is added to the system. 68.Pp 69.Nm 70hooks into the 71.Xr devctl 4 72device driver. 73This device driver has hooks into the device configuration system. 74When nodes are added or deleted from the tree, this device will 75deliver information about the event to 76.Nm . 77Once 78.Nm 79has parsed the message, it will search its action list for that kind 80of event and perform the action with the highest matching value. 81For most mundane uses, the default handlers are adequate. 82However, for more advanced users, the power is present to tweak every 83aspect of what happens. 84.Pp 85.Nm 86reads /etc/devd.conf and uses that file to drive the rest of the process. 87While the format of this file is described in 88.Xr devd.conf 5 89some basics are covered here. 90In the options section, one can define multiple directories to search 91for config files. 92All files in each of these directories are parsed. 93These files are intended to be installed by third party vendors that 94wish to hook into the 95.Nm 96system without modifying the user's other 97config files. 98.Sh SEE ALSO 99.Xr devctl 4 , 100.Xr devd.conf 5 101.Sh AUTHORS 102.An M. Warner Losh 103.Sh BUGS 104devd currently always runs "/etc/devd-generic $device $startstop" for 105all device events, regardless of what the config file says to do. 106