#!/usr/bin/python2.7
# Copyright (c) 2012, Niklas Femerstrand <nik@qnrq.se>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
# Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
# IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
# OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
# OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
import re
import os
import md5
import socket
import threading
import BaseHTTPServer
from optparse import OptionParser
from SimpleHTTPServer import SimpleHTTPRequestHandler
from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer

argparse = OptionParser()
argparse.add_option("-k", "--key", dest="key",
                                        help = "Optional, when set it adds a key to the panic signal.",
                                        metavar="<your key>")
argparse.add_option("-p", "--port", dest="port",
                                        help = "HTTP port to use",
                                        metavar="<your key>")

args = argparse.parse_args()

global key
key = args[0].key or ""

global port
port = int(args[0].port or 8080)

global signal
signal = "/\\x"
signal += "\\x".join(x.encode("hex") for x in md5.new("panic" + key).digest())

# Basic HTTP server that listens to GET /panic and triggers panic.
# Written to provide a standardized interface for panic triggering.
# To trigger panic through HTTP simply request http://localhost:port/panic
class panicHandler(BaseHTTPRequestHandler):
    def do_GET(self):
        req = "/\\x" + "\\x".join(x.encode("hex") for x in md5.new(re.sub("^\/", "", self.path)).digest())
        if req == signal:
            sendSignal()

def httpd():
    s = HTTPServer(('', port), panicHandler)
    s.serve_forever()

# TODO: Extend with a C lib that iterates through used physmem addresses and
#       overwrites values in a prio order before triggering poweroff.
# TODO: Use mountedDrives() to iterate and eject (crypto) mounts
def treatPanic():
    os.popen("truecrypt -d")
    # Linux, possibly more
    os.popen("shutdown -P now")
    # FreeBSD, possibly more
    os.popen("shutdown -p now")

def sigListener():
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
    s.bind(("", 1337)) # Listen on all devices

    while True:
        try:
            message, address = s.recvfrom(65)
            if message == signal:
                treatPanic()
        except:
            pass

def bcast():
    bcast = os.popen("ifconfig | grep -o \"broadcast [0-9]*\.[0-9]*\.[0-9]*\.[0-9]*\"").read()
    bcast = bcast.replace("broadcast ", "")
    return bcast

def sendSignal():
    s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
    s.sendto(signal, (bcast(), 1337))
    s.close()
    return 0


httpd = threading.Thread(name="httpd", target=httpd)
httpd.start()
sigListener = threading.Thread(name="sigListener", target=sigListener)
sigListener.start()
