devd. A daemon that hooks into the kernel's /dev/devctl to produce

arbitrary commands when devices come and go in the device tree (which is
different than the /dev directory).

This is an initial version.  Much of the planned power isn't here.
Instead of doing the full matching, we always run /etc/devd-generic.
/etc/devd.generic will go away at some point, I think.

I'm committing it in this early state so I can start getting feedback
from early adapters.

Approved by: re

1 files changed, 88 insertions, 0 deletions

diff --git a/sbin/devd/devd.8 b/sbin/devd/devd.8
new file mode 100644
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+++ b/sbin/devd/devd.8
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+.\"
+.\" Copyright (c) 2002 M. Warner Losh.
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd October 17, 2002
+.Dt DEVD 8
+.Os
+.Sh NAME
+.Nm devd
+.Nd "Device state change daemon"
+.Sh SYNOPSIS
+.Nm
+.Op Fl d
+.Sh DESCRIPTION
+The
+.Nm
+daemon provides a way to have userland programs run when certain
+kernel events happen.
+.Pp
+The following options are accepted.
+.Bl -tag -width indent
+.It Fl d
+Enable debugging messages and run in the foreground instead of
+becoming a daemon.
+.El
+.Sh IMPLEMENTATION NOTES
+.Nm 
+is a system daemon.
+It runs in the background all the time.
+When ever a device is added to or removed from the device tree, devd
+will cause a certain action to take place.
+In addition, when a device that is not matched enters the system, devd
+will also perform an action.
+.Pp
+.Nm 
+hooks into the
+.Xr 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 even to
+.Nm .
+Once 
+.Nm 
+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.
+.Pp
+.Nm reads /etc/devd.conf, and that drives the rest of the process.
+While the format of this file is described in 
+.Xr 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 each of these directories 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.
+.Sh SEE ALSO
+.Xr devctl 4 ,
+.Xr devd.conf 5
+.Sh AUTHORS
+.An M. Warner Losh