XTEND(8) BSD System Manager's Manual XTEND(8)NAMExtend — X-10 daemon
SYNOPSIS
/usr/libexec/xtend
DESCRIPTION
Xtend interfaces between user-level programs and the TW523 X-10 con‐
troller. It logs all packets received from the TW523, attempts to track
the status of all X-10 devices, and accepts socket connections from user-
level client programs that need to manipulate X-10 devices.
When xtend is started, it forks, releases the controlling terminal, then
opens its log file, where it subsequently records all X-10 activity and
diagnostic messages. It then begins processing packets received from the
TW523 and accepting connections one at a time from clients wishing to
issue X-10 commands.
Sending xtend a SIGHUP causes it to close and reopen its log file. This
is useful in shell scripts that rotate the log files to keep them from
growing indefinitely. If xtend receives a SIGTERM, it shuts down grace‐
fully and exits. A SIGPIPE causes xtend to abort the current client con‐
nection.
Xtend communicates with client processes by a simple protocol in which a
one-line command is sent by the client, and is acknowledged by a one-line
response from the daemon.
Xtend understands four types of commands:
status H U where H is a single letter house code, and U is a numeric
unit code, causes xtend to respond with one line of status
information about the specified device.
send H U N where H is a single-letter house code, U is either a numeric
unit code or a function code (see source file
xtend/packet.c) for a list, and N is a number indicating the
number of times (usually 2) the packet is to be transmitted
without gaps, causes xtend to perform the specified X-10
transmission. If the transmission was apparently success‐
ful, a single-line response containing OK is issued, other‐
wise a single-line response containing ERROR is produced.
dump causes xtend to dump the current status of all devices to an
ASCII file in the spool directory. The response OK is
issued, regardless of whether the status dump was success‐
ful.
monitor H U causes xtend to add the current client socket connection to
a list of clients that are to be notified about activity
concerning the specified X-10 device. The single-line
acknowledgement OK is returned if the maximum (currently 5)
number of such clients was not exceeded, otherwise ERROR is
returned. Xtend then returns to its normal mode of accept‐
ing connections from clients. However, each subsequent
change in the status of the specified device will cause
xtend to write one line of status information for the device
(in the same format as produced by the status command) to
the saved socket. This feature is useful for writing pro‐
grams that need to monitor the activity of devices, like
motion detectors, that can perform X-10 transmissions.
OPTIONS
None.
FILES
/dev/tw0 the TW523 special file
/var/run/tw523 socket for client connections
/var/run/xtend.pid pid file
/var/spool/xten/Log log file
/var/spool/xten/Status device status file (binary)
/var/spool/xten/status.out ASCII dump of device status
SEE ALSOxten(1), tw(4)AUTHORS
Eugene W. Stark ⟨stark@cs.sunysb.edu⟩
BUGS
There is currently no timeout on client socket connections, so a hung
client program can prevent other clients from accessing the daemon.
Xtend does the best it can at trying to track device status, but there is
usually no way it can tell when a device has been operated manually.
This is due to the fact that most X-10 devices are not able to respond to
queries about their status.
BSD October 30, 1993 BSD
