parse_elfnote.py - platform/ndk - Git at Google

 #!/usr/bin/env python3
 #
 # Copyright (C) 2016 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.
 #

 #
 # Dump the contents of the .note.android.ident section, a NOTE section
 # embedded into Android binaries. See here:
 #  - master: ndk/sources/crt/crtbrand.S
 #  - master: bionic/libc/arch-common/bionic/crtbrand.S
 #  - NDK before r14: development/ndk/platforms/common/src/crtbrand.c
 #
 # Note sections can also be dumped with `readelf -n`.
 #

 from __future__ import division, print_function

 import argparse
 import logging
 import shutil
 import struct
 import subprocess
 import sys
 from pathlib import Path

 SEC_NAME = ".note.android.ident"
 NDK_RESERVED_SIZE = 64


 def logger():
     """Returns the module logger."""
     return logging.getLogger(__name__)


 def round_up_to_nearest(val, step):
     """Round an integer, val, to the next multiple of a positive integer,
     step."""
     return (val + (step - 1)) // step * step


 class StructParser:
     def __init__(self, buf):
         self.buf = buf
         self.pos = 0

     @property
     def remaining(self):
         return len(self.buf) - self.pos

     @property
     def empty(self):
         return self.remaining == 0

     def read(self, read_len):
         buf = self.buf[self.pos : read_len + self.pos]
         self.pos += read_len
         return buf

     def read_struct(self, fmt, kind):
         fmt = struct.Struct(fmt)
         if self.remaining < fmt.size:
             sys.exit("error: {} was truncated".format(kind))
         return fmt.unpack(self.read(fmt.size))


 def iterate_notes(sec_data):
     sec_data = StructParser(sec_data)
     while not sec_data.empty:
         (namesz, descsz, kind) = sec_data.read_struct("<III", "note header")
         (name, desc) = sec_data.read_struct(
             "{}s{}s".format(
                 round_up_to_nearest(namesz, 4), round_up_to_nearest(descsz, 4)
             ),
             "note body",
         )
         name = name[:namesz]
         if len(name) > 0:
             if name[-1:] == b"\0":
                 name = name[:-1]
             else:
                 logger().warning("note name %s isn't NUL-terminated", name)
         yield name, kind, desc[:descsz]


 def dump_android_ident_note(note):
     note = StructParser(note)
     (android_api,) = note.read_struct("<I", "note descriptor")
     print("ABI_ANDROID_API: {}".format(android_api))
     if note.empty:
         return
     # Binaries generated by NDK r14 and later have these extra fields. Platform
     # binaries and binaries generated by older NDKs don't.
     ndk_version, ndk_build_number = note.read_struct(
         "{sz}s{sz}s".format(sz=NDK_RESERVED_SIZE), "note descriptor"
     )
     ndk_version = ndk_version.decode("utf-8")
     ndk_build_number = ndk_build_number.decode("utf-8")
     print("ABI_NDK_VERSION: {}".format(ndk_version.rstrip("\0")))
     print("ABI_NDK_BUILD_NUMBER: {}".format(ndk_build_number.rstrip("\0")))
     if not note.empty:
         logger().warning("excess data at end of descriptor")


 # Get the offset to a section from the output of readelf
 def get_section_pos(readelf: Path, sec_name: str, file_path: str) -> tuple[int, int]:
     cmd = [readelf, "--sections", "-W", file_path]
     output = subprocess.check_output(cmd)
     lines = output.decode("utf-8").splitlines()
     for line in lines:
         logger().debug('Checking line for "%s": %s', sec_name, line)
         # Looking for a line like the following (all whitespace of unknown
         # width).
         #
         #   [ 8] .note.android.ident NOTE 00000000 0000ec 000098 00 A 0 0 4
         #
         # The only column that might have internal whitespace is the first one.
         # Since we don't care about it, remove the head of the string until the
         # closing bracket, then split.
         if "]" not in line:
             continue
         line = line[line.index("]") + 1 :]

         sections = line.split()
         if len(sections) < 5 or sec_name != sections[0]:
             continue
         off = int(sections[3], 16)
         size = int(sections[4], 16)
         return (off, size)
     sys.exit("error: failed to find section: {}".format(sec_name))


 def get_ndk_install_path() -> Path | None:
     try:
         import ndk.paths  # pylint: disable=import-outside-toplevel

         path = ndk.paths.get_install_path()
         if path.exists():
             return path
         return None
     except ImportError:
         return None


 def readelf_from_ndk(ndk: Path) -> Path:
     if not ndk.exists():
         raise ValueError(f"--ndk is {ndk} but that path does not exist")
     prebuilt_dir = ndk / "toolchains/llvm/prebuilt"
     bins = list(prebuilt_dir.glob("*/bin"))
     if not bins:
         raise RuntimeError(f"{prebuilt_dir} contains no */bin")
     if len(bins) != 1:
         raise RuntimeError(f"{prebuilt_dir} contains more than one */bin")
     bin_dir = bins[0]

     readelf = (bin_dir / "llvm-readelf").with_suffix(
         ".exe" if sys.platform == "win32" else ""
     )
     if not readelf.exists():
         raise RuntimeError(f"{readelf} does not exist")
     return readelf


 def find_readelf(ndk: Path | None) -> Path:
     if ndk is not None:
         return readelf_from_ndk(ndk)
     if (install_path := get_ndk_install_path()) is not None:
         return readelf_from_ndk(install_path)
     if (readelf := shutil.which("llvm-readelf")) is not None:
         return Path(readelf)
     if (readelf := shutil.which("readelf")) is not None:
         return Path(readelf)
     raise RuntimeError(
         "Could not find llvm-readelf or readelf in PATH and could find find any NDK"
     )


 def parse_args():
     """Parses command line arguments."""
     parser = argparse.ArgumentParser()
     parser.add_argument("file_path", help="path of the ELF file with embedded ABI tags")
     parser.add_argument(
         "-v",
         "--verbose",
         dest="verbosity",
         action="count",
         default=0,
         help="Increase logging verbosity.",
     )
     parser.add_argument(
         "--ndk",
         type=Path,
         help="Path to the NDK. If given, the NDK's llvm-readelf will be used.",
     )
     return parser.parse_args()


 def main():
     args = parse_args()
     if args.verbosity == 1:
         logging.basicConfig(level=logging.INFO)
     elif args.verbosity >= 2:
         logging.basicConfig(level=logging.DEBUG)
     else:
         logging.basicConfig()

     file_path = args.file_path

     readelf = find_readelf(args.ndk)

     with open(file_path, "rb") as obj_file:
         (sec_off, sec_size) = get_section_pos(readelf, SEC_NAME, file_path)

         obj_file.seek(sec_off)
         sec_data = obj_file.read(sec_size)
         if len(sec_data) != sec_size:
             sys.exit("error: could not read {} section".format(SEC_NAME))

         print("----------ABI INFO----------")
         if len(sec_data) == 0:
             logger().warning("%s section is empty", SEC_NAME)
         for name, kind, desc in iterate_notes(sec_data):
             if (name, kind) == (b"Android", 1):
                 dump_android_ident_note(desc)
             else:
                 logger().warning(
                     "unrecognized note (name %s, type %d)", repr(name), kind
                 )


 if __name__ == "__main__":
     main()
	#!/usr/bin/env python3
	#
	# Copyright (C) 2016 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.
	#

	#
	# Dump the contents of the .note.android.ident section, a NOTE section
	# embedded into Android binaries. See here:
	# - master: ndk/sources/crt/crtbrand.S
	# - master: bionic/libc/arch-common/bionic/crtbrand.S
	# - NDK before r14: development/ndk/platforms/common/src/crtbrand.c
	#
	# Note sections can also be dumped with `readelf -n`.
	#

	from __future__ import division, print_function

	import argparse
	import logging
	import shutil
	import struct
	import subprocess
	import sys
	from pathlib import Path

	SEC_NAME = ".note.android.ident"
	NDK_RESERVED_SIZE = 64


	def logger():
	"""Returns the module logger."""
	return logging.getLogger(__name__)


	def round_up_to_nearest(val, step):
	"""Round an integer, val, to the next multiple of a positive integer,
	step."""
	return (val + (step - 1)) // step * step


	class StructParser:
	def __init__(self, buf):
	self.buf = buf
	self.pos = 0

	@property
	def remaining(self):
	return len(self.buf) - self.pos

	@property
	def empty(self):
	return self.remaining == 0

	def read(self, read_len):
	buf = self.buf[self.pos : read_len + self.pos]
	self.pos += read_len
	return buf

	def read_struct(self, fmt, kind):
	fmt = struct.Struct(fmt)
	if self.remaining < fmt.size:
	sys.exit("error: {} was truncated".format(kind))
	return fmt.unpack(self.read(fmt.size))


	def iterate_notes(sec_data):
	sec_data = StructParser(sec_data)
	while not sec_data.empty:
	(namesz, descsz, kind) = sec_data.read_struct("<III", "note header")
	(name, desc) = sec_data.read_struct(
	"{}s{}s".format(
	round_up_to_nearest(namesz, 4), round_up_to_nearest(descsz, 4)
	),
	"note body",
	)
	name = name[:namesz]
	if len(name) > 0:
	if name[-1:] == b"\0":
	name = name[:-1]
	else:
	logger().warning("note name %s isn't NUL-terminated", name)
	yield name, kind, desc[:descsz]


	def dump_android_ident_note(note):
	note = StructParser(note)
	(android_api,) = note.read_struct("<I", "note descriptor")
	print("ABI_ANDROID_API: {}".format(android_api))
	if note.empty:
	return
	# Binaries generated by NDK r14 and later have these extra fields. Platform
	# binaries and binaries generated by older NDKs don't.
	ndk_version, ndk_build_number = note.read_struct(
	"{sz}s{sz}s".format(sz=NDK_RESERVED_SIZE), "note descriptor"
	)
	ndk_version = ndk_version.decode("utf-8")
	ndk_build_number = ndk_build_number.decode("utf-8")
	print("ABI_NDK_VERSION: {}".format(ndk_version.rstrip("\0")))
	print("ABI_NDK_BUILD_NUMBER: {}".format(ndk_build_number.rstrip("\0")))
	if not note.empty:
	logger().warning("excess data at end of descriptor")


	# Get the offset to a section from the output of readelf
	def get_section_pos(readelf: Path, sec_name: str, file_path: str) -> tuple[int, int]:
	cmd = [readelf, "--sections", "-W", file_path]
	output = subprocess.check_output(cmd)
	lines = output.decode("utf-8").splitlines()
	for line in lines:
	logger().debug('Checking line for "%s": %s', sec_name, line)
	# Looking for a line like the following (all whitespace of unknown
	# width).
	#
	# [ 8] .note.android.ident NOTE 00000000 0000ec 000098 00 A 0 0 4
	#
	# The only column that might have internal whitespace is the first one.
	# Since we don't care about it, remove the head of the string until the
	# closing bracket, then split.
	if "]" not in line:
	continue
	line = line[line.index("]") + 1 :]

	sections = line.split()
	if len(sections) < 5 or sec_name != sections[0]:
	continue
	off = int(sections[3], 16)
	size = int(sections[4], 16)
	return (off, size)
	sys.exit("error: failed to find section: {}".format(sec_name))


	def get_ndk_install_path() -> Path \| None:
	try:
	import ndk.paths # pylint: disable=import-outside-toplevel

	path = ndk.paths.get_install_path()
	if path.exists():
	return path
	return None
	except ImportError:
	return None


	def readelf_from_ndk(ndk: Path) -> Path:
	if not ndk.exists():
	raise ValueError(f"--ndk is {ndk} but that path does not exist")
	prebuilt_dir = ndk / "toolchains/llvm/prebuilt"
	bins = list(prebuilt_dir.glob("*/bin"))
	if not bins:
	raise RuntimeError(f"{prebuilt_dir} contains no */bin")
	if len(bins) != 1:
	raise RuntimeError(f"{prebuilt_dir} contains more than one */bin")
	bin_dir = bins[0]

	readelf = (bin_dir / "llvm-readelf").with_suffix(
	".exe" if sys.platform == "win32" else ""
	)
	if not readelf.exists():
	raise RuntimeError(f"{readelf} does not exist")
	return readelf


	def find_readelf(ndk: Path \| None) -> Path:
	if ndk is not None:
	return readelf_from_ndk(ndk)
	if (install_path := get_ndk_install_path()) is not None:
	return readelf_from_ndk(install_path)
	if (readelf := shutil.which("llvm-readelf")) is not None:
	return Path(readelf)
	if (readelf := shutil.which("readelf")) is not None:
	return Path(readelf)
	raise RuntimeError(
	"Could not find llvm-readelf or readelf in PATH and could find find any NDK"
	)


	def parse_args():
	"""Parses command line arguments."""
	parser = argparse.ArgumentParser()
	parser.add_argument("file_path", help="path of the ELF file with embedded ABI tags")
	parser.add_argument(
	"-v",
	"--verbose",
	dest="verbosity",
	action="count",
	default=0,
	help="Increase logging verbosity.",
	)
	parser.add_argument(
	"--ndk",
	type=Path,
	help="Path to the NDK. If given, the NDK's llvm-readelf will be used.",
	)
	return parser.parse_args()


	def main():
	args = parse_args()
	if args.verbosity == 1:
	logging.basicConfig(level=logging.INFO)
	elif args.verbosity >= 2:
	logging.basicConfig(level=logging.DEBUG)
	else:
	logging.basicConfig()

	file_path = args.file_path

	readelf = find_readelf(args.ndk)

	with open(file_path, "rb") as obj_file:
	(sec_off, sec_size) = get_section_pos(readelf, SEC_NAME, file_path)

	obj_file.seek(sec_off)
	sec_data = obj_file.read(sec_size)
	if len(sec_data) != sec_size:
	sys.exit("error: could not read {} section".format(SEC_NAME))

	print("----------ABI INFO----------")
	if len(sec_data) == 0:
	logger().warning("%s section is empty", SEC_NAME)
	for name, kind, desc in iterate_notes(sec_data):
	if (name, kind) == (b"Android", 1):
	dump_android_ident_note(desc)
	else:
	logger().warning(
	"unrecognized note (name %s, type %d)", repr(name), kind
	)


	if __name__ == "__main__":
	main()