xref: /aosp_15_r20/system/update_engine/scripts/trim_ota_package.py (revision 5a9231315b4521097b8dc3750bc806fcafe0c72f)
1#!/usr/bin/env python3
2
3import zipfile
4import struct
5
6
7def readPayloadMetadata(zfp: zipfile.ZipFile, entry):
8  _MAGIC = b'CrAU'
9  # 8 bytes for version, 8 bytes for manifest length, 4 bytes for metadata signature length
10  HEADER_STRUCT = ">4sQQL"
11  HEADER_LEN = struct.calcsize(HEADER_STRUCT)
12  with zfp.open(entry) as fp:
13    header = fp.read(HEADER_LEN)
14    (magic, version, manifest_length,
15     metadata_signature_len) = struct.unpack(HEADER_STRUCT, header)
16    assert magic == _MAGIC
17    assert version == 2, "Unsupported major payload version " + str(version)
18    print(f"{manifest_length} {metadata_signature_len}")
19    return header + fp.read(manifest_length + metadata_signature_len)
20
21
22def main(argv):
23  if len(argv) != 3:
24    print("Usage:", argv[0], "<input file> <output file>")
25    return 1
26  infile = argv[1]
27  outfile = argv[2]
28  with zipfile.ZipFile(infile, "r") as inzfp, zipfile.ZipFile(outfile, "w") as outzfp:
29    for entry in inzfp.infolist():
30      if entry.filename.startswith("META") or entry.filename.endswith(".map") or entry.filename.endswith(".prop"):
31        outzfp.writestr(entry, inzfp.read(entry))
32      elif entry.filename == "payload.bin":
33        outzfp.writestr(entry, readPayloadMetadata(inzfp, entry))
34
35
36if __name__ == '__main__':
37  import sys
38  sys.exit(main(sys.argv))
39