tools/extract_kernel.py - LeafOS-Project/android_build - Gitiles

 #!/usr/bin/env python
 #
 # Copyright (C) 2018 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.

 """
 A tool to extract kernel information from a kernel image.
 """

 import argparse
 import subprocess
 import sys
 import re

 CONFIG_PREFIX = b'IKCFG_ST'
 GZIP_HEADER = b'\037\213\010'
 COMPRESSION_ALGO = (
     (["gzip", "-d"], GZIP_HEADER),
     (["xz", "-d"], b'\3757zXZ\000'),
     (["bzip2", "-d"], b'BZh'),
     (["lz4", "-d", "-l"], b'\002\041\114\030'),

     # These are not supported in the build system yet.
     # (["unlzma"], b'\135\0\0\0'),
     # (["lzop", "-d"], b'\211\114\132'),
 )

 # "Linux version " UTS_RELEASE " (" LINUX_COMPILE_BY "@"
 # LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION "\n";
 LINUX_BANNER_PREFIX = b'Linux version '
 LINUX_BANNER_REGEX = LINUX_BANNER_PREFIX.decode() + \
     r'(?P<release>(?P<version>[0-9]+[.][0-9]+[.][0-9]+).*) \(.*@.*\) \((?P<compiler>.*)\) .*\n'


 def get_from_release(input_bytes, start_idx, key):
   null_idx = input_bytes.find(b'\x00', start_idx)
   if null_idx < 0:
     return None
   try:
     linux_banner = input_bytes[start_idx:null_idx].decode()
   except UnicodeDecodeError:
     return None
   mo = re.match(LINUX_BANNER_REGEX, linux_banner)
   if mo:
     return mo.group(key)
   return None


 def dump_from_release(input_bytes, key):
   """
   Helper of dump_version and dump_release
   """
   idx = 0
   while True:
     idx = input_bytes.find(LINUX_BANNER_PREFIX, idx)
     if idx < 0:
       return None

     value = get_from_release(input_bytes, idx, key)
     if value:
       return value.encode()

     idx += len(LINUX_BANNER_PREFIX)


 def dump_version(input_bytes):
   """
   Dump kernel version, w.x.y, from input_bytes. Search for the string
   "Linux version " and do pattern matching after it. See LINUX_BANNER_REGEX.
   """
   return dump_from_release(input_bytes, "version")


 def dump_compiler(input_bytes):
   """
   Dump kernel version, w.x.y, from input_bytes. Search for the string
   "Linux version " and do pattern matching after it. See LINUX_BANNER_REGEX.
   """
   return dump_from_release(input_bytes, "compiler")


 def dump_release(input_bytes):
   """
   Dump kernel release, w.x.y-..., from input_bytes. Search for the string
   "Linux version " and do pattern matching after it. See LINUX_BANNER_REGEX.
   """
   return dump_from_release(input_bytes, "release")


 def dump_configs(input_bytes):
   """
   Dump kernel configuration from input_bytes. This can be done when
   CONFIG_IKCONFIG is enabled, which is a requirement on Treble devices.

   The kernel configuration is archived in GZip format right after the magic
   string 'IKCFG_ST' in the built kernel.
   """

   # Search for magic string + GZip header
   idx = input_bytes.find(CONFIG_PREFIX + GZIP_HEADER)
   if idx < 0:
     return None

   # Seek to the start of the archive
   idx += len(CONFIG_PREFIX)

   sp = subprocess.Popen(["gzip", "-d", "-c"], stdin=subprocess.PIPE,
                         stdout=subprocess.PIPE, stderr=subprocess.PIPE)
   o, _ = sp.communicate(input=input_bytes[idx:])
   if sp.returncode == 1: # error
     return None

   # success or trailing garbage warning
   assert sp.returncode in (0, 2), sp.returncode

   return o


 def try_decompress_bytes(cmd, input_bytes):
   sp = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE,
                         stderr=subprocess.PIPE)
   o, _ = sp.communicate(input=input_bytes)
   # ignore errors
   return o


 def try_decompress(cmd, search_bytes, input_bytes):
   idx = 0
   while True:
     idx = input_bytes.find(search_bytes, idx)
     if idx < 0:
       return

     yield try_decompress_bytes(cmd, input_bytes[idx:])
     idx += 1


 def decompress_dump(func, input_bytes):
   """
   Run func(input_bytes) first; and if that fails (returns value evaluates to
   False), then try different decompression algorithm before running func.
   """
   o = func(input_bytes)
   if o:
     return o
   for cmd, search_bytes in COMPRESSION_ALGO:
     for decompressed in try_decompress(cmd, search_bytes, input_bytes):
       if decompressed:
         o = decompress_dump(func, decompressed)
         if o:
           return o
     # Force decompress the whole file even if header doesn't match
     decompressed = try_decompress_bytes(cmd, input_bytes)
     if decompressed:
       o = decompress_dump(func, decompressed)
       if o:
         return o


 def dump_to_file(f, dump_fn, input_bytes, desc):
   """
   Call decompress_dump(dump_fn, input_bytes) and write to f. If it fails, return
   False; otherwise return True.
   """
   if f is not None:
     o = decompress_dump(dump_fn, input_bytes)
     if o:
       f.write(o)
     else:
       sys.stderr.write(
           "Cannot extract kernel {}".format(desc))
       return False
   return True

 def to_bytes_io(b):
   """
   Make b, which is either sys.stdout or sys.stdin, receive bytes as arguments.
   """
   return b.buffer if sys.version_info.major == 3 else b

 def main():
   parser = argparse.ArgumentParser(
       formatter_class=argparse.RawTextHelpFormatter,
       description=__doc__ +
       "\nThese algorithms are tried when decompressing the image:\n    " +
       " ".join(tup[0][0] for tup in COMPRESSION_ALGO))
   parser.add_argument('--input',
                       help='Input kernel image. If not specified, use stdin',
                       metavar='FILE',
                       type=argparse.FileType('rb'),
                       default=to_bytes_io(sys.stdin))
   parser.add_argument('--output-configs',
                       help='If specified, write configs. Use stdout if no file '
                            'is specified.',
                       metavar='FILE',
                       nargs='?',
                       type=argparse.FileType('wb'),
                       const=to_bytes_io(sys.stdout))
   parser.add_argument('--output-version',
                       help='If specified, write version. Use stdout if no file '
                            'is specified.',
                       metavar='FILE',
                       nargs='?',
                       type=argparse.FileType('wb'),
                       const=to_bytes_io(sys.stdout))
   parser.add_argument('--output-release',
                       help='If specified, write kernel release. Use stdout if '
                            'no file is specified.',
                       metavar='FILE',
                       nargs='?',
                       type=argparse.FileType('wb'),
                       const=to_bytes_io(sys.stdout))
   parser.add_argument('--output-compiler',
                       help='If specified, write the compiler information. Use stdout if no file '
                            'is specified.',
                       metavar='FILE',
                       nargs='?',
                       type=argparse.FileType('wb'),
                       const=to_bytes_io(sys.stdout))
   parser.add_argument('--tools',
                       help='Decompression tools to use. If not specified, PATH '
                            'is searched.',
                       metavar='ALGORITHM:EXECUTABLE',
                       nargs='*')
   args = parser.parse_args()

   tools = {pair[0]: pair[1]
            for pair in (token.split(':') for token in args.tools or [])}
   for cmd, _ in COMPRESSION_ALGO:
     if cmd[0] in tools:
       cmd[0] = tools[cmd[0]]

   input_bytes = args.input.read()

   ret = 0
   if not dump_to_file(args.output_configs, dump_configs, input_bytes,
                       "configs in {}".format(args.input.name)):
     ret = 1
   if not dump_to_file(args.output_version, dump_version, input_bytes,
                       "version in {}".format(args.input.name)):
     ret = 1
   if not dump_to_file(args.output_release, dump_release, input_bytes,
                       "kernel release in {}".format(args.input.name)):
     ret = 1

   if not dump_to_file(args.output_compiler, dump_compiler, input_bytes,
                       "kernel compiler in {}".format(args.input.name)):
     ret = 1

   return ret


 if __name__ == '__main__':
   sys.exit(main())
	#!/usr/bin/env python
	#
	# Copyright (C) 2018 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.

	"""
	A tool to extract kernel information from a kernel image.
	"""

	import argparse
	import subprocess
	import sys
	import re

	CONFIG_PREFIX = b'IKCFG_ST'
	GZIP_HEADER = b'\037\213\010'
	COMPRESSION_ALGO = (
	(["gzip", "-d"], GZIP_HEADER),
	(["xz", "-d"], b'\3757zXZ\000'),
	(["bzip2", "-d"], b'BZh'),
	(["lz4", "-d", "-l"], b'\002\041\114\030'),

	# These are not supported in the build system yet.
	# (["unlzma"], b'\135\0\0\0'),
	# (["lzop", "-d"], b'\211\114\132'),
	)

	# "Linux version " UTS_RELEASE " (" LINUX_COMPILE_BY "@"
	# LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION "\n";
	LINUX_BANNER_PREFIX = b'Linux version '
	LINUX_BANNER_REGEX = LINUX_BANNER_PREFIX.decode() + \
	r'(?P<release>(?P<version>[0-9]+[.][0-9]+[.][0-9]+).) \(.@.\) \((?P<compiler>.)\) .*\n'


	def get_from_release(input_bytes, start_idx, key):
	null_idx = input_bytes.find(b'\x00', start_idx)
	if null_idx < 0:
	return None
	try:
	linux_banner = input_bytes[start_idx:null_idx].decode()
	except UnicodeDecodeError:
	return None
	mo = re.match(LINUX_BANNER_REGEX, linux_banner)
	if mo:
	return mo.group(key)
	return None


	def dump_from_release(input_bytes, key):
	"""
	Helper of dump_version and dump_release
	"""
	idx = 0
	while True:
	idx = input_bytes.find(LINUX_BANNER_PREFIX, idx)
	if idx < 0:
	return None

	value = get_from_release(input_bytes, idx, key)
	if value:
	return value.encode()

	idx += len(LINUX_BANNER_PREFIX)


	def dump_version(input_bytes):
	"""
	Dump kernel version, w.x.y, from input_bytes. Search for the string
	"Linux version " and do pattern matching after it. See LINUX_BANNER_REGEX.
	"""
	return dump_from_release(input_bytes, "version")


	def dump_compiler(input_bytes):
	"""
	Dump kernel version, w.x.y, from input_bytes. Search for the string
	"Linux version " and do pattern matching after it. See LINUX_BANNER_REGEX.
	"""
	return dump_from_release(input_bytes, "compiler")


	def dump_release(input_bytes):
	"""
	Dump kernel release, w.x.y-..., from input_bytes. Search for the string
	"Linux version " and do pattern matching after it. See LINUX_BANNER_REGEX.
	"""
	return dump_from_release(input_bytes, "release")


	def dump_configs(input_bytes):
	"""
	Dump kernel configuration from input_bytes. This can be done when
	CONFIG_IKCONFIG is enabled, which is a requirement on Treble devices.

	The kernel configuration is archived in GZip format right after the magic
	string 'IKCFG_ST' in the built kernel.
	"""

	# Search for magic string + GZip header
	idx = input_bytes.find(CONFIG_PREFIX + GZIP_HEADER)
	if idx < 0:
	return None

	# Seek to the start of the archive
	idx += len(CONFIG_PREFIX)

	sp = subprocess.Popen(["gzip", "-d", "-c"], stdin=subprocess.PIPE,
	stdout=subprocess.PIPE, stderr=subprocess.PIPE)
	o, _ = sp.communicate(input=input_bytes[idx:])
	if sp.returncode == 1: # error
	return None

	# success or trailing garbage warning
	assert sp.returncode in (0, 2), sp.returncode

	return o


	def try_decompress_bytes(cmd, input_bytes):
	sp = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE,
	stderr=subprocess.PIPE)
	o, _ = sp.communicate(input=input_bytes)
	# ignore errors
	return o


	def try_decompress(cmd, search_bytes, input_bytes):
	idx = 0
	while True:
	idx = input_bytes.find(search_bytes, idx)
	if idx < 0:
	return

	yield try_decompress_bytes(cmd, input_bytes[idx:])
	idx += 1


	def decompress_dump(func, input_bytes):
	"""
	Run func(input_bytes) first; and if that fails (returns value evaluates to
	False), then try different decompression algorithm before running func.
	"""
	o = func(input_bytes)
	if o:
	return o
	for cmd, search_bytes in COMPRESSION_ALGO:
	for decompressed in try_decompress(cmd, search_bytes, input_bytes):
	if decompressed:
	o = decompress_dump(func, decompressed)
	if o:
	return o
	# Force decompress the whole file even if header doesn't match
	decompressed = try_decompress_bytes(cmd, input_bytes)
	if decompressed:
	o = decompress_dump(func, decompressed)
	if o:
	return o


	def dump_to_file(f, dump_fn, input_bytes, desc):
	"""
	Call decompress_dump(dump_fn, input_bytes) and write to f. If it fails, return
	False; otherwise return True.
	"""
	if f is not None:
	o = decompress_dump(dump_fn, input_bytes)
	if o:
	f.write(o)
	else:
	sys.stderr.write(
	"Cannot extract kernel {}".format(desc))
	return False
	return True

	def to_bytes_io(b):
	"""
	Make b, which is either sys.stdout or sys.stdin, receive bytes as arguments.
	"""
	return b.buffer if sys.version_info.major == 3 else b

	def main():
	parser = argparse.ArgumentParser(
	formatter_class=argparse.RawTextHelpFormatter,
	description=__doc__ +
	"\nThese algorithms are tried when decompressing the image:\n " +
	" ".join(tup[0][0] for tup in COMPRESSION_ALGO))
	parser.add_argument('--input',
	help='Input kernel image. If not specified, use stdin',
	metavar='FILE',
	type=argparse.FileType('rb'),
	default=to_bytes_io(sys.stdin))
	parser.add_argument('--output-configs',
	help='If specified, write configs. Use stdout if no file '
	'is specified.',
	metavar='FILE',
	nargs='?',
	type=argparse.FileType('wb'),
	const=to_bytes_io(sys.stdout))
	parser.add_argument('--output-version',
	help='If specified, write version. Use stdout if no file '
	'is specified.',
	metavar='FILE',
	nargs='?',
	type=argparse.FileType('wb'),
	const=to_bytes_io(sys.stdout))
	parser.add_argument('--output-release',
	help='If specified, write kernel release. Use stdout if '
	'no file is specified.',
	metavar='FILE',
	nargs='?',
	type=argparse.FileType('wb'),
	const=to_bytes_io(sys.stdout))
	parser.add_argument('--output-compiler',
	help='If specified, write the compiler information. Use stdout if no file '
	'is specified.',
	metavar='FILE',
	nargs='?',
	type=argparse.FileType('wb'),
	const=to_bytes_io(sys.stdout))
	parser.add_argument('--tools',
	help='Decompression tools to use. If not specified, PATH '
	'is searched.',
	metavar='ALGORITHM:EXECUTABLE',
	nargs='*')
	args = parser.parse_args()

	tools = {pair[0]: pair[1]
	for pair in (token.split(':') for token in args.tools or [])}
	for cmd, _ in COMPRESSION_ALGO:
	if cmd[0] in tools:
	cmd[0] = tools[cmd[0]]

	input_bytes = args.input.read()

	ret = 0
	if not dump_to_file(args.output_configs, dump_configs, input_bytes,
	"configs in {}".format(args.input.name)):
	ret = 1
	if not dump_to_file(args.output_version, dump_version, input_bytes,
	"version in {}".format(args.input.name)):
	ret = 1
	if not dump_to_file(args.output_release, dump_release, input_bytes,
	"kernel release in {}".format(args.input.name)):
	ret = 1

	if not dump_to_file(args.output_compiler, dump_compiler, input_bytes,
	"kernel compiler in {}".format(args.input.name)):
	ret = 1

	return ret


	if __name__ == '__main__':
	sys.exit(main())