packkernelimg/packkernelimg

#!/usr/bin/env python
#Copyright (c) 2016, The Linux Foundation. All rights reserved.
#Not a contribution.Apache license notifications and license are
#retained for attribution purposes only.
# 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
import sys
import re
import os

def filesize(f):
    if f is None:
        return 0
    try:
        return fstat(f.fileno()).st_size
    except OSError:
        return 0
def parse_cmdline():
    parser = ArgumentParser()
    parser.add_argument('--kernel', help='Path to UNCOMPRESSED kernel image',required=True)
    parser.add_argument('--dt', help='Path to device tree files', required=True)
    parser.add_argument('--dt_list', help='List of device tree files to pick up', required=False)
    return parser.parse_args()

def main():
    args = parse_cmdline()
    KERNEL_TYPE = 'UNCOMPRESSED_IMG'.encode()
    kernel = open(args.kernel, 'rb')
    str = kernel.readline()
    if args.dt_list is not None:
        dtb_list = args.dt_list.split()
    if str.startswith('UNCOMPRESSED_IMG'):
        print("File already patched")
        exit(0)
    kernel.seek(0)
    print("Kernel size is %d" % filesize(kernel))
    #Temp file to hold output
    output = open(args.kernel + 'tmp', 'wb')
    output.write(pack('16s', KERNEL_TYPE))
    output.write(pack('1I', filesize(kernel)))
    output.write(kernel.read())
    #Walk through the device tree dir and append all blobs to the output
    for root, directories, files in os.walk(args.dt):
        for filename in files:
            if filename.endswith('.dtb'):
                if args.dt_list is not None:
                    if filename not in dtb_list:
                        continue
                print("Processing file %s" % filename)
                filepath = os.path.join(root, filename)
                with open(filepath) as dtb_file:
                    output.write(dtb_file.read())
    output.close()
    kernel.close()
    #Write output from tmp file to original
    output = open(args.kernel, 'wb')
    kernel = open(args.kernel + 'tmp', 'rb')
    output.write(kernel.read())
    output.close()
    kernel.close()
    #delete tmp file
    os.remove(args.kernel + 'tmp')
if __name__ == '__main__':
    main()