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#!/usr/bin/python
# Hotplug script for gpsd by Eric S. Raymond, March 2005
# This script is part of the gpsd distribution: see http://gpsd.berlios.de
# Can be called like "gpsd.hotplug [+-]/dev/ttyUSB0" for test purposes.
import sys, os, syslog, glob, socket
CONTROL_SOCKET = "/var/run/gpsd.sock"
def gpsd_control_connect():
"Acquire a connection to the GPSD control socket."
try:
sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM, 0)
sock.connect(CONTROL_SOCKET)
sockfile = sock.makefile()
except socket.error, msg:
if sock:
sock.close()
sock = None
sockfile = None
if not sock:
syslog.syslog("gpsd is not running or control socket is unreachable")
return None
else:
return sockfile
def wake_up_gpsd(devpath, action):
subnodes = glob.glob("/sys" + devpath + "/*")
subnodes = map(os.path.basename, subnodes)
subnodes = filter(lambda s: s.startswith("ttyUSB"), subnodes)
if len(subnodes) == 0:
syslog.syslog("no ttyUSB device under " + devpath)
return
elif len(subnodes) > 1:
syslog.syslog("too many ttyUSB devices under " + devpath)
return
else:
tty = "/dev/" + subnodes[0]
syslog.syslog(tty + " has gone active")
# Next get a connection to gpsd; start one if not already running
connect = gpsd_connect()
if connect:
syslog.syslog("reached a running gpsd")
elif action == 'add':
syslog.syslog("attempting to launch gpsd")
os.system("gpsd -F " + CONTROL_SOCKET)
connect = gpsd_control_connect()
if not connect:
return
# We've got a live connection to the gpsd control socket. No
# need to parse response, because gpsd will lock on to the
# device if it's really a GPS and ignore it if it's not.
if action == 'add':
connect.write("+%s\r\n" % tty)
elif action == 'remove':
connect.write("-%s\r\n" % tty)
connect.close()
return
def hotplug(action, devpath):
syslog.openlog('gpsdplug', 0, syslog.LOG_DAEMON)
syslog.syslog("gpsdplug begins with action: %s" % action)
if not devpath:
syslog.syslog("No device")
else:
wake_up_gpsd(devpath, action)
syslog.syslog("gpsdplug ends")
syslog.closelog()
if __name__ == '__main__':
if len(sys.argv) == 1: # Called as hotplug script
hotplug(os.getenv("ACTION"), os.getenv("DEVPATH"))
else: # Called by hand for testing
fp = gpsd_control_connect()
fp.write(sys.argv[1]+"\n")
fp.close()
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