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1#!/usr/bin/env python3
2#
3# Copyright (C) 2021 The Android Open Source Project
4#
5# Licensed under the Apache License, Version 2.0 (the "License");
6# you may not use this file except in compliance with the License.
7# You may obtain a copy of the License at
8#
9#      http://www.apache.org/licenses/LICENSE-2.0
10#
11# Unless required by applicable law or agreed to in writing, software
12# distributed under the License is distributed on an "AS IS" BASIS,
13# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14# See the License for the specific language governing permissions and
15# limitations under the License.
16#
17
18"""Command-line tool for converting OTA payloads to VABC style COW images."""
19
20import os
21import sys
22import tempfile
23import zipfile
24import subprocess
25
26
27def IsSparseImage(filepath):
28  """Determine if an image is a sparse image
29  Args:
30    filepath: str, a path to an .img file
31
32  Returns:
33    return true iff the filepath is a sparse image.
34
35  """
36  with open(filepath, 'rb') as fp:
37    # Magic for android sparse image format
38    # https://source.android.com/devices/bootloader/images
39    return fp.read(4) == b'\x3A\xFF\x26\xED'
40
41
42def ConvertCOW(ota_path, target_file_path, tmp_dir, output_dir):
43  """Convert ota payload to COW IMAGE
44  Args:
45    ota_path: str, path to ota.zip
46    target_file_path: str, path to target_file.zip,
47      must be the target build for OTA.
48    tmp_dir: A temp dir as scratch space
49    output_dir: A directory where all converted COW images will be written.
50  """
51  with zipfile.ZipFile(ota_path) as ota_zip:
52    payload_path = ota_zip.extract("payload.bin", output_dir)
53  with zipfile.ZipFile(target_file_path) as zfp:
54    for fileinfo in zfp.infolist():
55      img_name = os.path.basename(fileinfo.filename)
56      if not fileinfo.filename.endswith(".img"):
57        continue
58      if fileinfo.filename.startswith("IMAGES/") or \
59              fileinfo.filename.startswith("RADIO/"):
60        img_path = zfp.extract(fileinfo, tmp_dir)
61        target_img_path = os.path.join(output_dir, img_name)
62        if IsSparseImage(img_path):
63          subprocess.check_call(["simg2img", img_path, target_img_path])
64        else:
65          os.rename(img_path, target_img_path)
66        print("Extracted", fileinfo.filename, "size:", fileinfo.file_size)
67
68  subprocess.call(["cow_converter", payload_path,
69                   output_dir])
70
71
72def main():
73  if len(sys.argv) != 4:
74    print(
75        "Usage:", sys.argv[0], "<your_ota.zip> <target_file.zip> <output dir>")
76    return 1
77  ota_path = sys.argv[1]
78  target_file_path = sys.argv[2]
79  output_dir = sys.argv[3]
80  os.makedirs(output_dir, exist_ok=True)
81  with tempfile.TemporaryDirectory() as tmp_dir:
82    ConvertCOW(ota_path, target_file_path, tmp_dir, output_dir)
83  return 0
84
85
86if __name__ == '__main__':
87  sys.exit(main())
88