#!/usr/bin/env python
#
# Author: Bas van der Vlies <basv@sara.nl>
# Date  : 16 February 2002
#
# Tester: Walter de Jong <walter@sara.nl>
#
# CVS info
#  $Date: 2002/08/16 07:43:21 $
#  $Revision: 1.9 $
#
# 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
#
"""
Usage: pxeconfig [-d|--directory <pxe_config_dir> ]

With this program you can configure which PXE configuration file
to use when a node boots. The program will ask the following questions:
  1) Network address (Class C-network address only)
  2) Starting number
  3) Ending number
  4) Which PXE config file to use 

For example, if the answers are: 
  1) 10.168.44
  2) 2
  3) 4
  4) default.node_install

Then the result is that is create symbolic links in /tftpboot/pxelinux.cfg:
  0AA82C02 ----> default.node_install
  0AA82C03 ----> default.node_install
  0AA82C04 ----> default.node_install
"""

import string
import sys
import os
import glob
import getopt

# DEBUG
#
DEBUG=0

# Constants
#
PXE_CONF_DIR='/tftpboot/pxelinux.cfg'
NADDR=0
PXEFILE=1
START=2
END=3
SHORTOPT_LIST='d:'
LONGOPT_LIST=['directory=']

def choice_pxe_configfile():
  """
  Let user choose which pxeconfig file to use.
  """

  os.chdir(PXE_CONF_DIR)

  # Try to determine to which file the default symlink points, and 
  # if it exists, remove it from the list.
  #
  try:
    default_file = os.readlink('default')
  except OSError:
    default_file = None
    pass

  files = glob.glob('default.*')
  if not files:
    print 'There are no pxe config files starting with: default.'
    sys.exit(1)

  if default_file:
    files.remove(default_file)
 

  print 'Which pxe config file must we use: ?' 
  i = 1   
  for file in files:
    print "%d : %s" %(i,file)
    i = i +1

  while 1:
    index = raw_input('Select a number: ')
    try:
      index = int(index)
    except ValueError:
      index = len(files) + 1

    # Is the user smart enough to select
    # the right value??
    #
    if 0 < index <= len(files): break

  return files[index-1]

def create_links(list):
  """
  Create the links in the PXE_CONF_DIR,
    list : A list containing: network hex address, pxe config file, 
           start number, end number
  """
  os.chdir(PXE_CONF_DIR)
  naddr = list[NADDR]
  pxe_filename = list[PXEFILE]
  for i in range(list[START], list[END]+1):
    haddr = '%s%02X' %(naddr, i)
    if DEBUG:
      print 'linking %s to %s' %(haddr, pxe_filename)

    if os.path.exists(haddr):
       os.unlink(haddr)

    os.symlink(pxe_filename, haddr)


def check_network(net):
  """
  This function checks if the give network is a Class C-network and will
  convert the network address to a hex address if true.
  """
  d = string.split(net, '.')

  if len(d) != 3:
    print('Only C-class nerwork addresses are supported!!!')
    sys.exit(1)

  # Check if we have valid network values
  r = ''
  for i in d:
    i = check_number(i)
    r = '%s%02X' %(r,i)

  if DEBUG:
    print r

  return r

def check_number(number):
  """
  This functions checks if the input is between 0 < number < 255:
     number : is a string
  """
  try:
    n = int(number)
  except ValueError, detail:
    print detail
    sys.exit(1)

  if 0 <= n <= 255:
    return n
  else:
    print '%s is not a valid number, must be between 0 and 255' %number
    sys.exit(1)

def interactive():

  iptable = {}

  print __doc__

  network = raw_input('Give network address (xxx.xxx.xxx): ') 
  naddr = check_network(network)

  start = raw_input('Starting number: ') 
  start = check_number(start)

  end = raw_input('Ending number: ') 
  end = check_number(end)

  pxe_filename = choice_pxe_configfile()

  iptable[network] = []
  iptable[network].append(naddr)
  iptable[network].append(pxe_filename)
  iptable[network].append(int(start))
  iptable[network].append(int(end))

  for net in iptable.keys():
    if DEBUG:
      print net, iptable[net]    
    create_links(iptable[net])


def check_args(argv):
  """
  command line option:
    -d/--directory <dir>
      Where <dir> is the directory where the pxe config files reside.
  """
  global PXE_CONF_DIR
  try:
    opts, args = getopt.getopt(argv[1:], SHORTOPT_LIST, LONGOPT_LIST)
  except getopt.error, detail:
    print check_args.__doc__
    print detail
    sys.exit(1)

  if opts:
    opt, PXE_CONF_DIR = opts[0]

  if not os.path.isdir(PXE_CONF_DIR):
    print 'Directory %s does not exists' %PXE_CONF_DIR
    sys.exit(1)

def main():
  check_args(sys.argv)
  interactive()

if __name__ == '__main__':
  main()