#!/usr/bin/env python
#
# Copyright (c) 2003-2007 Andrea Luzzardi <scox@sig11.org>
#
# This file is part of the pam_usb project. pam_usb is free software;
# you can redistribute it and/or modify it under the terms of the GNU General
# Public License version 2, as published by the Free Software Foundation.
#
# pam_usb is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc., 59 Temple
# Place, Suite 330, Boston, MA  02111-1307  USA

import os
import sys
import pwd
import getopt
import syslog
import gobject
import dbus
if getattr(dbus, 'version', (0,0,0)) >= (0,41,0):
    import dbus.glib
try:
    import cElementTree as et
except ImportError:
    import elementtree.ElementTree as et

class HotPlugDevice:
    def __init__(self, serial):
        self.__udi = None
        self.__serial = serial
        self.__callbacks = []
        self.__bus = dbus.SystemBus()
        self.__running = False

    def run(self):
        self.__scanDevices()
        self.__registerSignals()
        self.__running = True
        gobject.MainLoop().run()
        print 'signals registered'

    def addCallback(self, callback):
        self.__callbacks.append(callback)

    def __scanDevices(self):
        halService = self.__bus.get_object('org.freedesktop.Hal',
                                           '/org/freedesktop/Hal/Manager')
        halManager = dbus.Interface(halService, 'org.freedesktop.Hal.Manager')
        for udi in halManager.FindDeviceStringMatch('info.bus', 'usb_device'):
            self.__deviceAdded(udi)

    def __registerSignals(self):
        for signal, callback in (('DeviceAdded', self.__deviceAdded),
                                 ('DeviceRemoved', self.__deviceRemoved)):
            self.__bus.add_signal_receiver(callback,
                                           signal,
                                           'org.freedesktop.Hal.Manager',
                                           'org.freedesktop.Hal',
                                           '/org/freedesktop/Hal/Manager')

    def __deviceAdded(self, udi):
        if self.__udi is not None:
            return
        deviceObj = self.__bus.get_object('org.freedesktop.Hal',
                                          udi)
        deviceProperties = deviceObj.GetAllProperties(
            dbus_interface = 'org.freedesktop.Hal.Device')
        if not deviceProperties.has_key('usb_device.serial'):
            return
        if deviceProperties['usb_device.serial'] != self.__serial:
            return
        self.__udi = udi
        if self.__running:
            [ cb('added') for cb in self.__callbacks ]

    def __deviceRemoved(self, udi):
        if self.__udi is None:
            return
        if self.__udi != udi:
            return
        self.__udi = None
        if self.__running:
            [ cb('removed') for cb in self.__callbacks ]

class Log:
    def __init__(self):
        syslog.openlog('pamusb-agent', syslog.LOG_PID | syslog.LOG_PERROR,
                       syslog.LOG_AUTH)

    def info(self, message):
        self.__logMessage(syslog.LOG_NOTICE, message)

    def error(self, message):
        self.__logMessage(syslog.LOG_ERR, message)

    def __logMessage(self, priority, message):
        syslog.syslog(priority, message)

def usage():
    print 'Usage: %s [--config file] [--daemon] [--path pamusb-check\'s path]' % \
          os.path.basename(__file__)
    sys.exit(1)

import getopt

try:
    opts, args = getopt.getopt(sys.argv[1:], "hc:dp:",
                               ["help", "config=", "daemon", "path="])
except getopt.GetoptError:
    usage()

options = {'configFile' : '/etc/pamusb.conf',
            'daemon' : False,
            'path' : '/usr/bin/pamusb-check'}

if len(args) != 0:
    usage()

for o, a in opts:
    if o in ('-h', '--help'):
        usage()
    if o in ('-c', '--config'):
        options['configFile'] = a
    if o in ('-d', '--daemon'):
        options['daemon'] = True
    if o in ('-p', '--path'):
        options['path'] = a


if not os.path.exists(options['path']):
    print '%s not found.' % options['path']
    print "You might specify manually pamusb-check's location using --path."
    usage()

username = pwd.getpwuid(os.getuid())[0]

logger = Log()

doc = et.parse(options['configFile'])
users = doc.findall('users/user')
for user in users:
    if user.get('id') == username:
        break
else:
    logger.error('User %s not found in configuration file' % username)
    sys.exit(1)

events = {
    'lock' : [],
    'unlock' : []
    }

for hotplug in user.findall('hotplug'):
    events[hotplug.get('event')].append(hotplug.text)

deviceName = user.find('device').text

devices = doc.findall("devices/device")
for device in devices:
    if device.get('id') == deviceName:
        break
else:
    logger.error('Device %s not found in configurtion file' % deviceName)
    sys.exit(1)

serial = device.find('serial').text

def authChangeCallback(event):
    if event == 'removed':
        logger.info('Device "%s" has been removed, ' \
                    'locking down user "%s"...' % (deviceName, username))
        for cmd in events['lock']:
            logger.info('Running "%s"' % cmd)
            os.system(cmd)
        logger.info('Locked.')
        return

    logger.info('Device "%s" has been inserted. ' \
                'Performing verification...' % deviceName)
    cmdLine = "%s -q -c %s -u %s -s pamusb-agent -a" % (options['path'],
                                                        options['configFile'],
                                                        username)
    logger.info('Executing "%s"' % cmdLine)
    if not os.system(cmdLine):
        logger.info('Authentication succeeded. ' \
                    'Unlocking user "%s"...' % username)
        for cmd in events['unlock']:
            logger.info('Running "%s"' % cmd)
            os.system(cmd)
        logger.info('Unlocked.')
    else:
        logger.info('Authentication failed for device %s. ' \
                    'Keeping user "%s" locked down.' % (deviceName, username))

hpDev = HotPlugDevice(serial)
hpDev.addCallback(authChangeCallback)


if options['daemon'] and os.fork():
    sys.exit(0)

logger.info('pamusb-agent up and running.')
logger.info('Watching device "%s" for user "%s"' % (deviceName, username))

try:
    hpDev.run()
except KeyboardInterrupt:
    logger.error('Caught keyboard interruption, exiting...')