| #!/usr/bin/env python |
| # Copyright 2017 Google Inc. |
| # |
| # 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. |
| # |
| ################################################################################ |
| |
| from __future__ import print_function |
| import argparse |
| import os |
| import re |
| import shutil |
| import subprocess |
| import sys |
| |
| INSTRUMENTED_LIBRARIES_DIRNAME = 'instrumented_libraries' |
| MSAN_LIBS_PATH = os.getenv('MSAN_LIBS_PATH', '/msan') |
| |
| |
| def IsElf(file_path): |
| """Whether if the file is an elf file.""" |
| with open(file_path) as f: |
| return f.read(4) == '\x7fELF' |
| |
| |
| def Ldd(binary_path): |
| """Run ldd on a file.""" |
| try: |
| output = subprocess.check_output(['ldd', binary_path], stderr=subprocess.STDOUT) |
| except subprocess.CalledProcessError: |
| print('Failed to call ldd on', binary_path, file=sys.stderr) |
| return [] |
| |
| libs = [] |
| |
| OUTPUT_PATTERN = re.compile(r'\s*([^\s]+)\s*=>\s*([^\s]+)') |
| for line in output.splitlines(): |
| match = OUTPUT_PATTERN.match(line) |
| if not match: |
| continue |
| |
| libs.append((match.group(1), match.group(2))) |
| |
| return libs |
| |
| |
| def FindLib(path): |
| """Find instrumented version of lib.""" |
| candidate_path = os.path.join(MSAN_LIBS_PATH, path[1:]) |
| if os.path.exists(candidate_path): |
| return candidate_path |
| |
| for lib_dir in os.listdir(MSAN_LIBS_PATH): |
| candidate_path = os.path.join(MSAN_LIBS_PATH, lib_dir, path[1:]) |
| if os.path.exists(candidate_path): |
| return candidate_path |
| |
| return None |
| |
| |
| def PatchBinary(binary_path, instrumented_dir): |
| """Patch binary to link to instrumented libs.""" |
| extra_rpaths = set() |
| |
| for name, path in Ldd(binary_path): |
| if not os.path.isabs(path): |
| continue |
| |
| instrumented_path = FindLib(path) |
| if not instrumented_path: |
| print('WARNING: Instrumented library not found for', path, |
| file=sys.stderr) |
| continue |
| |
| target_path = os.path.join(instrumented_dir, path[1:]) |
| if not os.path.exists(target_path): |
| print('Copying instrumented lib to', target_path) |
| target_dir = os.path.dirname(target_path) |
| if not os.path.exists(target_dir): |
| os.makedirs(target_dir) |
| shutil.copy2(instrumented_path, target_path) |
| |
| extra_rpaths.add( |
| os.path.join('$ORIGIN', INSTRUMENTED_LIBRARIES_DIRNAME, |
| os.path.dirname(path[1:]))) |
| |
| if not extra_rpaths: |
| return |
| |
| existing_rpaths = subprocess.check_output( |
| ['patchelf', '--print-rpath', binary_path]).strip() |
| processed_rpaths = ':'.join(extra_rpaths) |
| if existing_rpaths: |
| processed_rpaths += ':' + existing_rpaths |
| print('Patching rpath for', binary_path, 'from', existing_rpaths, 'to', |
| processed_rpaths) |
| |
| subprocess.check_call( |
| ['patchelf', '--force-rpath', '--set-rpath', |
| processed_rpaths, binary_path]) |
| |
| |
| def PatchBuild(output_directory): |
| """Patch build to use msan libs.""" |
| instrumented_dir = os.path.join(output_directory, |
| INSTRUMENTED_LIBRARIES_DIRNAME) |
| if not os.path.exists(instrumented_dir): |
| os.mkdir(instrumented_dir) |
| |
| for root_dir, _, filenames in os.walk(output_directory): |
| for filename in filenames: |
| file_path = os.path.join(root_dir, filename) |
| |
| if os.path.islink(file_path): |
| continue |
| |
| if not IsElf(file_path): |
| continue |
| |
| PatchBinary(file_path, instrumented_dir) |
| |
| |
| def main(): |
| parser = argparse.ArgumentParser('patch_build.py', description='MSan build patcher.') |
| parser.add_argument('output_dir', help='Output directory.') |
| |
| args = parser.parse_args() |
| |
| PatchBuild(os.path.abspath(args.output_dir)) |
| |
| |
| if __name__ == '__main__': |
| main() |