#!/usr/bin/python2.6
# -*- coding: utf-8 -*-
#
# Univention Grub menu.lst generator
#
# Copyright 2012 Univention GmbH
#
# http://www.univention.de/
#
# All rights reserved.
#
# The source code of this program is made available
# under the terms of the GNU Affero General Public License version 3
# (GNU AGPL V3) as published by the Free Software Foundation.
#
# Binary versions of this program provided by Univention to you as
# well as other copyrighted, protected or trademarked materials like
# Logos, graphics, fonts, specific documentations and configurations,
# cryptographic keys etc. are subject to a license agreement between
# you and Univention and not subject to the GNU AGPL V3.
#
# In the case you use this program under the terms of the GNU AGPL V3,
# the program is provided 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public
# License with the Debian GNU/Linux or Univention distribution in file
# /usr/share/common-licenses/AGPL-3; if not, see
# <http://www.gnu.org/licenses/>.

import os
import sys
import optparse
from shutil import copyfile
from glob import glob
from distutils.version import LooseVersion
import univention.config_registry as ucr

configRegistry = ucr.ConfigRegistry()
configRegistry.load()

f = open('/proc/cmdline')
try:
	args = "%s splash=nosplash" % f.read().strip()
finally:
	f.close()

parser = optparse.OptionParser()
parser.add_option("-f", "--force", action="store_true",
		dest="force", default=False, help="Force writing menu.lst")
parser.add_option("-n", "--dry-run", action="store_true",
		dest="dry", default=False, help="Print to stdout instead of menu.lst")
parser.add_option("-c", "--commandline", "--append", action="store",
		dest="args", default=args, help="Overwrite kernel command line arguments")
options, args = parser.parse_args()

if configRegistry.is_false('grub/generate-menu-lst', False):
	print >>sys.stderr, "Disables via grub/generate-menu-lst"
	if options.force:
		print >>sys.stderr, "Forced!"
	else:
		sys.exit(0)

os.chdir("/boot")
if os.path.exists("grub/menu.lst"):
	f = open("grub/menu.lst", "r")
	for line in f:
		if "auto-generated through univention-grub-generate-menu-lst" in line:
			break
	else:
		print >>sys.stderr, "menu.lst already exists. This typically happens if you have updated from UCS 2.4"
		print >>sys.stderr, "and haven't converted from chain loading"
		if options.force:
			print >>sys.stderr, "Forced!"
		else:
			sys.exit(0)

kernels = glob("vmlinuz-*")
if not kernels:
	print >>sys.stderr, "No kernels found matching /boot/vmlinuz-*."
	sys.exit(0)

if os.path.exists("grub/menu.lst"):
	if options.dry:
		print >>sys.stderr, "Skip moving!"
	else:
		copyfile("grub/menu.lst", "grub/menu.lst.bak")

print >>sys.stderr, "Generating legacy menu.lst from current kernels"

if options.dry:
	out = sys.stdout
else:
	out = open("grub/menu.lst", "w")
try:
	print >>out, "# This Grub configuration is auto-generated through univention-grub-generate-menu-lst."
	print >>out, "# It is used when booting UCS 3.0 as a Xen DomU with an older version of PyGrub."
	print >>out, ""
	print >>out, "default 0"
	print >>out, "timeout %s" % configRegistry.get("grub/timeout", "5")
	print >>out, ""

	for kernel in sorted(kernels, key=LooseVersion, reverse=True):
		kver = kernel[8:] # vmlinuz-
		initrd = "initrd.img-%s" % kver
		print >>out, "title           UCS, kernel %s" % kver
		print >>out, "root            (hd0,0)"
		print >>out, "kernel          /%s %s" % (kernel, options.args)
		if os.path.exists(initrd):
			print >>out, "initrd          /%s" % initrd
		print >>out, ""
finally:
	out.close()