mirror of
https://github.com/google/pebble.git
synced 2025-03-15 16:51:21 +00:00
147 lines
4.9 KiB
Python
147 lines
4.9 KiB
Python
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# Copyright 2024 Google LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import struct
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import uuid
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class PebbleAppHeader(object):
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MAGIC = 'PBLAPP\x00\x00'
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# 10 bytes
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HEADER_STRUCT_DEFINITION = [
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'8s', # header
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'2B', # struct version
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]
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HEADER_STRUCT = struct.Struct(''.join(HEADER_STRUCT_DEFINITION))
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# 116 bytes
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V1_STRUCT_VERSION = (0x08, 0x01)
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V1_STRUCT_DEFINTION = [
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# format, name, deserialization transform, serialization transform
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('B', 'sdk_version_major', None, None),
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('B', 'sdk_version_minor', None, None),
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('B', 'app_version_major', None, None),
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('B', 'app_version_minor', None, None),
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('H', 'app_size', None, None),
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('I', 'offset', None, None),
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('I', 'crc', None, None),
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('32s', 'app_name', lambda bytes: bytes.rstrip('\0'), None),
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('32s', 'company_name', lambda bytes: bytes.rstrip('\0'), None),
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('I', 'icon_resource_id', None, None),
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('I', 'symbol_table_addr', None, None),
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('I', 'flags', None, None),
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('I', 'relocation_list_index', None, None),
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('I', 'num_relocation_entries', None, None),
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('16s', 'uuid', lambda s: uuid.UUID(bytes=s), lambda u: u.bytes),
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]
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# 120 bytes
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V2_STRUCT_VERSION = (0x10, 0x00)
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V2_STRUCT_DEFINTION = list(V1_STRUCT_DEFINTION)
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del V2_STRUCT_DEFINTION[12] # relocation list was dropped in v2.x
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V2_STRUCT_DEFINTION += [
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('I', 'resource_crc', None, None),
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('I', 'resource_timestamp', None, None),
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('H', 'virtual_size', None, None),
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]
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V2_HEADER_LENGTH = 10 + 120
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DEFINITION_MAP = {
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V1_STRUCT_VERSION: V1_STRUCT_DEFINTION,
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V2_STRUCT_VERSION: V2_STRUCT_DEFINTION,
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}
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@classmethod
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def get_def_and_struct(cls, struct_version):
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definition = cls.DEFINITION_MAP.get(struct_version)
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if not definition:
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raise Exception("Unsupported "
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"struct version %s" % str(struct_version))
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fmt = '<' + reduce(lambda s, t: s + t[0], definition, '')
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s = struct.Struct(fmt)
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return definition, s
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@classmethod
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def deserialize(cls, app_bin):
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header_size = cls.HEADER_STRUCT.size
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header = app_bin[0:header_size]
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values = cls.HEADER_STRUCT.unpack(header)
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struct_version = (values[1], values[2])
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info = {
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'sentinel': values[0],
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'struct_version_major': struct_version[0],
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'struct_version_minor': struct_version[1],
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}
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if info['sentinel'] != cls.MAGIC:
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raise Exception('This is not a pebble watchapp')
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definition, s = cls.get_def_and_struct(struct_version)
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values = s.unpack(app_bin[header_size:header_size + s.size])
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for value, elem in zip(values, definition):
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field_name = elem[1]
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transform = elem[2]
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info[field_name] = value if not transform else transform(value)
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return info
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def serialize(self):
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struct_version = (self._info['struct_version_major'],
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self._info['struct_version_minor'])
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header = PebbleAppHeader.HEADER_STRUCT.pack(PebbleAppHeader.MAGIC,
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*struct_version)
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definition, s = self.__class__.get_def_and_struct(struct_version)
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def map_args(elem):
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value = self._info[elem[1]]
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transform = elem[3]
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return value if not transform else transform(value)
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args = map(map_args, definition)
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return header + s.pack(*args)
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def __init__(self, app_bin_bytes):
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self._info = PebbleAppHeader.deserialize(app_bin_bytes)
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def __getattr__(self, name):
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value = self._info.get(name)
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if value is None:
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raise Exception("Unknown field %s" % name)
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return value
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def __setattr__(self, name, value):
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if name == '_info':
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super(PebbleAppHeader, self).__setattr__(name, value)
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self._info[name] = value
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def __repr__(self):
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return self._info.__repr__()
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def __str__(self):
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return self.__repr__()
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if __name__ == '__main__':
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import argparse
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import pprint
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parser = argparse.ArgumentParser()
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parser.add_argument('bin_file')
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args = parser.parse_args()
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with open(args.bin_file, 'rb') as f:
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app_info = PebbleAppHeader.deserialize(f.read())
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pprint.pprint(app_info)
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