diff options
Diffstat (limited to 'system/gpsd/gpsd.hotplug')
| -rw-r--r-- | system/gpsd/gpsd.hotplug | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/system/gpsd/gpsd.hotplug b/system/gpsd/gpsd.hotplug new file mode 100644 index 0000000000..805f941998 --- /dev/null +++ b/system/gpsd/gpsd.hotplug @@ -0,0 +1,124 @@ +#!/usr/bin/python +# +# This file is Copyright (c) 2010 by the GPSD project +# BSD terms apply: see the file COPYING in the distribution root for details. +# +# 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 [add|remove] /dev/ttyUSB0" for test +# purposes. +import sys, time, os, syslog, glob, socket, stat + +CONTROL_SOCKET = os.getenv('GPSD_SOCKET') or "/var/run/gpsd.sock" +GPSD_OPTIONS = os.getenv('GPSD_OPTIONS') or "" + +WHEREAMI = __file__ + +def gpsd_control_connect(complain=True): + "Acquire a connection to the GPSD control socket." + if not os.path.exists(CONTROL_SOCKET): + syslog.syslog("socket %s doesn't exist" % CONTROL_SOCKET) + return None + try: + sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM, 0) + sock.connect(CONTROL_SOCKET) + except socket.error, msg: + if complain: + syslog.syslog("socket %s creation failure: %s" % (CONTROL_SOCKET, msg)) + if sock: + sock.close() + sock = None + #else: + # syslog.syslog("socket %s created OK" % CONTROL_SOCKET) + return sock + +def gpsd_control(action, argument): + "Pass a command to gpsd; start the daemon if not already running." + syslog.syslog("gpsd_control(action=%s, arg=%s)" % (action, argument)) + connect = gpsd_control_connect(complain=False) + if connect: + syslog.syslog("reached a running gpsd") + elif action == 'add': + gpsdcmd = "gpsd %s -F %s" % (GPSD_OPTIONS, CONTROL_SOCKET) + syslog.syslog("launching %s" % gpsdcmd) + os.system(gpsdcmd) + connect = gpsd_control_connect(complain=True) + if not connect: + syslog.syslog("can't reach gpsd") + return None + # We've got a live connection to the gpsd control socket. No + # need to parse the 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': + # Force the group-read & group-write bits on, so gpsd will still be + # able to use this device after dropping root privileges. + os.chmod(argument, stat.S_IMODE(os.stat(argument)[stat.ST_MODE])|0660) + connect.sendall("+%s\r\n" % argument) + connect.recv(12) + elif action == 'remove': + connect.sendall("-%s\r\n" % argument) + connect.recv(12) + elif action == 'send': + connect.sendall("%s\r\n" % argument) + connect.recv(12) + connect.close() + #syslog.syslog("gpsd_control ends") + return action + +def hotplug(action, devpath): + #syslog.syslog("ACTION=%s DEVPATH=%s" % (action,devpath)) + if not devpath: + syslog.syslog("No device") + else: + 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("waiting for " + tty) + while not os.path.exists(tty): + time.sleep(1) + syslog.syslog(tty + " has gone active") + + gpsd_control(action, tty) + + remover = os.getenv("REMOVER") + #syslog.syslog("REMOVER=%s" % remover) + fp = open(remover, "w") + fp.write(WHEREAMI + " remove " + tty) + fp.close() + os.chmod(remover, stat.S_IRUSR|stat.S_IXUSR|stat.S_IRGRP|stat.S_IXGRP) + return + +if __name__ == '__main__': + # In recent versions of udev, the gpsd script runs in series with + # the task that creates the real /dev/ttyUSB0 device + # node. Unfortunately, the gpsd script runs BEFORE the creation of + # the node, and the node is not created until after you kill the + # gpsd script, because the gpsd script waits forever for the node + # to appear. + # + # This is a race condition, and is best fixed by running the + # actual wait/hotplug portion in the background. + pid = os.fork() + if not pid: + syslog.openlog('gpsd.hotplug', 0, syslog.LOG_DAEMON) + try: + if len(sys.argv) == 1: # Called as hotplug script + hotplug(os.getenv("ACTION"), os.getenv("DEVPATH")) + else: # Called by hand for testing + gpsd_control(sys.argv[1], sys.argv[2]) + except: + (exc_type, exc_value, exc_traceback) = sys.exc_info() + syslog.syslog("gpsd.hotplug: exception %s yields %s" % (exc_type, exc_value)) + raise exc_type, exc_value, exc_traceback + #syslog.syslog("gpsd.hotplug ends") + syslog.closelog() + |