state change daemon
daemon provides a way to have userland
programs run when certain kernel events happen.
The following options are accepted.
- Run in the foreground instead of becoming a daemon and log
additional information for debugging.
- Use configuration file
file instead of the default
/etc/devd.conf. If option
-f is specified more than once, the last file
specified is used.
- Limit concurrent socket connections to
num. The default connection limit is
- Do not process all pending events before becoming a daemon.
Instead, call daemon right away.
- Quiet mode. Only log messages at priority LOG_WARNING or
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
. For example,
when an Ethernet adapter is added to
the system, and kill the dhclient(8)
when the same adapter is removed. Another example would be for
to use a table to locate and load via
the proper driver for an unrecognized
device that is added to the system.
utility hooks into the
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
. Once devd
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.
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 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
modifying the user's other config files.
allows only one active reader,
multiplexes it, forwarding all events to any
number of connected clients. Clients connect by opening the SOCK_SEQPACKET
domain socket at
- The default devd configuration
- The socket used by devd to
communicate with its clients.
- A deprecated socket retained for use with old clients.
M. Warner Losh