#!/usr/bin/env python # Copyright 2014 The Chromium Authors. All rights reserved. # Use of this source code is governed by a BSD-style license that can be # found in the LICENSE file. import glob import optparse import os import shutil import subprocess import sys sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', '..', 'third_party', 'pefile')) import pefile def reorder_imports(input_dir, output_dir, architecture): """Swap chrome_elf.dll to be the first import of chrome.exe. Also copy over any related files that might be needed (pdbs, manifests etc.). """ # TODO(thakis): See if there is a reliable way to write the # correct executable in the first place, so that this script # only needs to verify that and not write a whole new exe. input_image = os.path.join(input_dir, 'chrome.exe') output_image = os.path.join(output_dir, 'chrome.exe') # pefile mmap()s the whole executable, and then parses parts of # it into python data structures for ease of processing. # To write the file again, only the mmap'd data is written back, # so modifying the parsed python objects generally has no effect. # However, parsed raw data ends up in pe.Structure instances, # and these all get serialized back when the file gets written. # So things that are in a Structure must have their data set # through the Structure, while other data must bet set through # the set_bytes_*() methods. pe = pefile.PE(input_image, fast_load=True) if architecture == 'x64': assert pe.PE_TYPE == pefile.OPTIONAL_HEADER_MAGIC_PE_PLUS else: assert pe.PE_TYPE == pefile.OPTIONAL_HEADER_MAGIC_PE pe.parse_data_directories(directories=[ pefile.DIRECTORY_ENTRY['IMAGE_DIRECTORY_ENTRY_IMPORT']]) found_elf = False for i, peimport in enumerate(pe.DIRECTORY_ENTRY_IMPORT): if peimport.dll.lower() == 'chrome_elf.dll': assert not found_elf, 'only one chrome_elf.dll import expected' found_elf = True if i > 0: swap = pe.DIRECTORY_ENTRY_IMPORT[0] # Morally we want to swap peimport.struct and swap.struct here, # but the pe module doesn't expose a public method on Structure # to get all data of a Structure without explicitly listing all # field names. # NB: OriginalFirstThunk and Characteristics are an union both at # offset 0, handling just one of them is enough. peimport.struct.OriginalFirstThunk, swap.struct.OriginalFirstThunk = \ swap.struct.OriginalFirstThunk, peimport.struct.OriginalFirstThunk peimport.struct.TimeDateStamp, swap.struct.TimeDateStamp = \ swap.struct.TimeDateStamp, peimport.struct.TimeDateStamp peimport.struct.ForwarderChain, swap.struct.ForwarderChain = \ swap.struct.ForwarderChain, peimport.struct.ForwarderChain peimport.struct.Name, swap.struct.Name = \ swap.struct.Name, peimport.struct.Name peimport.struct.FirstThunk, swap.struct.FirstThunk = \ swap.struct.FirstThunk, peimport.struct.FirstThunk assert found_elf, 'chrome_elf.dll import not found' pe.write(filename=output_image) for fname in glob.iglob(os.path.join(input_dir, 'chrome.exe.*')): shutil.copy(fname, os.path.join(output_dir, os.path.basename(fname))) return 0 def main(argv): usage = 'reorder_imports.py -i -o -a ' parser = optparse.OptionParser(usage=usage) parser.add_option('-i', '--input', help='reorder chrome.exe in DIR', metavar='DIR') parser.add_option('-o', '--output', help='write new chrome.exe to DIR', metavar='DIR') parser.add_option('-a', '--arch', help='architecture of build (optional)', default='ia32') opts, args = parser.parse_args() if not opts.input or not opts.output: parser.error('Please provide and input and output directory') return reorder_imports(opts.input, opts.output, opts.arch) if __name__ == "__main__": sys.exit(main(sys.argv[1:]))