device 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 above.
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,
will execute actions
when an Ethernet adapter is added to the system, and kill the
instance 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
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.
or the alternate
configuration file specified with a
option and uses that file to drive the rest of the process. While the format
of this file is described in
some basics are covered here. In the
section, one can define multiple
directories to search for config files. All files in these directories whose
names match the pattern *.conf
These files are intended to be installed by third party vendors that wish to
hook into the
system without 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 UNIX
domain socket at
- The default
- The socket used by
devd to communicate
with its clients.
- A deprecated socket retained for use with old clients.
utility first appeared in
M. Warner Losh