| # Copyright 2015 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 itertools |
| |
| |
| def get_signature(file_object, elffile_module): |
| """Computes a unique signature of a library file. |
| |
| We only hash the .text section of the library in order to make the hash |
| resistant to stripping (we want the same hash for the same library with debug |
| symbols kept or stripped). |
| """ |
| try: |
| elf = elffile_module.ELFFile(file_object) |
| text_section = elf.get_section_by_name('.text') |
| except elffile_module.common.ELFError: |
| return None |
| file_object.seek(text_section['sh_offset']) |
| data = file_object.read(min(4096, text_section['sh_size'])) |
| def combine((i, c)): |
| return i ^ ord(c) |
| result = 16 * [0] |
| for i in xrange(0, len(data), len(result)): |
| result = map(combine, |
| itertools.izip_longest(result, |
| data[i:i + len(result)], |
| fillvalue='\0')) |
| return ''.join(["%02x" % x for x in result]) |
