# Copyright (C) 2002
#
# This file is part of the pxeconfig utils
#
# This program is free software; you can redistribute it and/or modify it 
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2, or (at your option) any
# later version.
#
# This program 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
#
# SVN info
#  $Id: pxeconfigd.py 206 2012-12-18 11:53:42Z bas $
"""
Author: Bas van der Vlies <basv@sara.nl>
Date  : 12 February 2002
Desc. : This script is used to control how a node is booted with PXE
        enabled network cards. The node boots and fetch a pxe
        config file which tells how the node must boot. This daemon
        enables a client to remove his/here pxe config file. With the
        next boot it will use the default one.

        command line option:
          -V/--version 
            Prints the version number and exits
          
        Note:
          This server can ONLY be started from inetd/xinetd.
"""
import time
import socket
import sys
import os
import string
import syslog
import getopt

# PXE modules
from pxe_global import *

# DEBUG
#
DEBUG=1

# Some Global Constants
#
BUFSIZE=4096
STDIN=0
STDOUT=1
SHORTOPT_LIST='V'
LONGOPT_LIST=['version']

PXE_CONF_DIR = '/tftpboot/pxelinux.cfg'
VERSION = '4.2.0'

# Give the current time
#
def now():
    return time.ctime(time.time())


def remove_link(ip, arp_cmd):
	"""
	This removes the pxe config filename for the host that is connected:
		ip      : ip address of the client host
		arp_cmd : For Dynamic ips, look up the mac address via arp
	"""

	## translate ip address ---> hex address 
	#
	d = string.split(ip, '.')
	haddr = '%02X%02X%02X%02X' %(int(d[0]), int(d[1]), int(d[2]), int(d[3])) 

	file = os.path.join(PXE_CONF_DIR, haddr)
	if DEBUG:
		print file

  	if not os.path.exists(file): 

		##
		# No ARP command set, just return
		#
		if not arp_cmd:
			return

		else:
			##
			#  arp -n 192.168.146.112 
			# Address          HWtype  HWaddress           Flags Mask Iface
			# 192.168.146.112  ether   00:23:ae:fd:cf:74   C          vlan133

			cmd = '%s %s' %(arp_cmd, ip)
			lines = os.popen(cmd).readlines()
			for line in lines:
				if line.startswith(ip):
					t = line.split()
					mac_addr = t[2] 
					haddr = '01-%s' %(mac_addr.replace(':', '-').lower())

					file = os.path.join(PXE_CONF_DIR, haddr) 
					if DEBUG:
						print file

					if not os.path.exists(file): 
						return

	if DEBUG:
		print 'file = %s' %file

	if os.path.islink(file): 
		try:
			os.unlink(file)
			syslog.openlog("pxeconfigd")
			syslog.syslog(syslog.LOG_INFO, file)
      			syslog.closelog()
		except OSError:
			err_msg = "No permission at directory: %s" %PXE_CONF_DIR
      			os.write(STDOUT, err_msg)
      			sys.exit(1)


# This function handles the client connection. It closes
# the connection if there is no data
#
def handleConnection(settings):
	"""
	Determines which host connects to the server
	""" 
	
	# Determine client address
	# 
	try:
		client_addr = socket.fromfd(sys.stdin.fileno(), socket.AF_INET, 
                          socket.SOCK_STREAM)
		client_ip = client_addr.getpeername()[0] 
	except socket.error, detail:
		error =  "pxeconfigd can only be started from inetd!!!"
		raise PxeConfig, error 
		
	
	if DEBUG:
		print 'ip = %s' %(client_ip) 

	try:
		cmd = '%s %s' %(settings['daemon_script_hook'], client_ip)
		print cmd
		os.system(cmd)
	except KeyError:
		pass

	try:
		arp_cmd = settings['arp_command']
	except KeyError:
		arp_cmd = None

	remove_link(client_ip, arp_cmd)
	sys.exit(0)

def check_args(argv, settings):
	"""
	Must we use another directory for the PXE configuration
	"""
	global PXE_CONF_DIR 
	
	try:
		opts, args = getopt.getopt(argv[1:], SHORTOPT_LIST, LONGOPT_LIST)
	except getopt.error, detail:
		print __doc__
		print detail
		sys.exit(1) 
		
	for opt, value in opts:
		if opt in ['-V', '--version']:
			print VERSION
			sys.exit(0)

	try:
		PXE_CONF_DIR = settings['pxe_config_dir']
	except KeyError:
		pass 
		
	PXE_CONF_DIR = os.path.realpath(PXE_CONF_DIR) 
	if not os.path.isdir(PXE_CONF_DIR):
		error =  'pxeconfig directory: %s does not exists' %(PXE_CONF_DIR)
		raise PxeConfig, error

def server():
  """Start the daemon
  """
  parser_config, default_settings = ReadConfig()
  check_args(sys.argv, default_settings)
  handleConnection(default_settings)

if __name__ == '__main__':
  server()