#!/usr/bin/env python
# Copyright 2015, The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import print_function
from sys import argv, exit, stderr
from argparse import ArgumentParser, FileType, Action
from os import fstat
from struct import pack
from hashlib import sha1
def filesize(f):
if f is None:
return 0
try:
return fstat(f.fileno()).st_size
except OSError:
return 0
def update_sha(sha, f):
if f:
sha.update(f.read())
f.seek(0)
sha.update(pack('I', filesize(f)))
else:
sha.update(pack('I', 0))
def pad_file(f, padding):
pad = (padding - (f.tell() & (padding - 1))) & (padding - 1)
f.write(pack(str(pad) + 'x'))
def write_header(args):
BOOT_MAGIC = 'ANDROID!'.encode()
args.output.write(pack('8s', BOOT_MAGIC))
args.output.write(pack('8I',
filesize(args.kernel), # size in bytes
args.base + args.kernel_offset, # physical load addr
filesize(args.ramdisk), # size in bytes
args.base + args.ramdisk_offset, # physical load addr
filesize(args.second), # size in bytes
args.base + args.second_offset, # physical load addr
args.base + args.tags_offset, # physical addr for kernel tags
args.pagesize)) # flash page size we assume
args.output.write(pack('8x')) # future expansion: should be 0
args.output.write(pack('16s', args.board.encode())) # asciiz product name
args.output.write(pack('512s', args.cmdline[:512].encode()))
sha = sha1()
update_sha(sha, args.kernel)
update_sha(sha, args.ramdisk)
update_sha(sha, args.second)
img_id = pack('32s', sha.digest())
args.output.write(img_id)
args.output.write(pack('1024s', args.cmdline[512:].encode()))
pad_file(args.output, args.pagesize)
return img_id
class ValidateStrLenAction(Action):
def __init__(self, option_strings, dest, nargs=None, **kwargs):
if 'maxlen' not in kwargs:
raise ValueError('maxlen must be set')
self.maxlen = int(kwargs['maxlen'])
del kwargs['maxlen']
super(ValidateStrLenAction, self).__init__(option_strings, dest, **kwargs)
def __call__(self, parser, namespace, values, option_string=None):
if len(values) > self.maxlen:
raise ValueError('String argument too long: max {0:d}, got {1:d}'.
format(self.maxlen, len(values)))
setattr(namespace, self.dest, values)
def write_padded_file(f_out, f_in, padding):
if f_in is None:
return
f_out.write(f_in.read())
pad_file(f_out, padding)
def parse_cmdline():
parser = ArgumentParser()
parser.add_argument('--kernel', help='path to the kernel', type=FileType('rb'),
required=True)
parser.add_argument('--ramdisk', help='path to the ramdisk', type=FileType('rb'))
parser.add_argument('--second', help='path to the 2nd bootloader', type=FileType('rb'))
parser.add_argument('--cmdline', help='extra arguments to be passed on the '
'kernel command line', default='', action=ValidateStrLenAction, maxlen=1536)
parser.add_argument('--base', help='base address', type=int, default=0x10000000)
parser.add_argument('----kernel_offset', help='kernel offset', type=int, default=0x00008000)
parser.add_argument('--ramdisk_offset', help='ramdisk offset', type=int, default=0x01000000)
parser.add_argument('--second_offset', help='2nd bootloader offset', type=int,
default=0x00f00000)
parser.add_argument('--tags_offset', help='tags offset', type=int, default=0x00000100)
parser.add_argument('--board', help='board name', default='', action=ValidateStrLenAction,
maxlen=16)
parser.add_argument('--pagesize', help='page size', type=int,
choices=[2**i for i in range(11,15)], default=2048)
parser.add_argument('--id', help='print the image ID on standard output',
action='store_true')
parser.add_argument('-o', '--output', help='output file name', type=FileType('wb'),
required=True)
return parser.parse_args()
def write_data(args):
write_padded_file(args.output, args.kernel, args.pagesize)
write_padded_file(args.output, args.ramdisk, args.pagesize)
write_padded_file(args.output, args.second, args.pagesize)
def main():
args = parse_cmdline()
img_id = write_header(args)
write_data(args)
if args.id:
print('0x' + ''.join('{:02x}'.format(ord(c)) for c in img_id))
if __name__ == '__main__':
main()
