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enigmail  1.4.3
check_debug_ranges.py
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00001 # ***** BEGIN LICENSE BLOCK *****
00002 # Version: MPL 1.1/GPL 2.0/LGPL 2.1
00003 #
00004 # The contents of this file are subject to the Mozilla Public License Version
00005 # 1.1 (the "License"); you may not use this file except in compliance with
00006 # the License. You may obtain a copy of the License at
00007 # http://www.mozilla.org/MPL/
00008 #
00009 # Software distributed under the License is distributed on an "AS IS" basis,
00010 # WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
00011 # for the specific language governing rights and limitations under the
00012 # License.
00013 #
00014 # The Original Code is mozilla.org
00015 #
00016 # The Initial Developer of the Original Code is
00017 # the Mozilla Foundation
00018 # Portions created by the Initial Developer are Copyright (C) 2011
00019 # the Initial Developer. All Rights Reserved.
00020 #
00021 # Contributor(s):
00022 # Mike Hommey <mh@glandium.org>
00023 #
00024 # Alternatively, the contents of this file may be used under the terms of
00025 # either the GNU General Public License Version 2 or later (the "GPL"), or
00026 # the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
00027 # in which case the provisions of the GPL or the LGPL are applicable instead
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00030 # use your version of this file under the terms of the MPL, indicate your
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00033 # the provisions above, a recipient may use your version of this file under
00034 # the terms of any one of the MPL, the GPL or the LGPL.
00035 #
00036 # ***** END LICENSE BLOCK *****
00037 
00038 # This script returns the number of items for the DW_AT_ranges corresponding
00039 # to a given compilation unit. This is used as a helper to find a bug in some
00040 # versions of GNU ld.
00041 
00042 import subprocess
00043 import sys
00044 import re
00045 
00046 def get_range_for(compilation_unit, debug_info):
00047     '''Returns the range offset for a given compilation unit
00048        in a given debug_info.'''
00049     name = ranges = ''
00050     search_cu = False
00051     for nfo in debug_info.splitlines():
00052         if 'DW_TAG_compile_unit' in nfo:
00053             search_cu = True
00054         elif 'DW_TAG_' in nfo or not nfo.strip():
00055             if name == compilation_unit:
00056                 return int(ranges, 16)
00057             name = ranges = ''
00058             search_cu = False
00059         if search_cu:
00060             if 'DW_AT_name' in nfo:
00061                 name = nfo.rsplit(None, 1)[1]
00062             elif 'DW_AT_ranges' in nfo:
00063                 ranges = nfo.rsplit(None, 1)[1]
00064     return None
00065 
00066 def get_range_length(range, debug_ranges):
00067     '''Returns the number of items in the range starting at the
00068        given offset.'''
00069     length = 0
00070     for line in debug_ranges.splitlines():
00071         m = re.match('\s*([0-9a-fA-F]+)\s+([0-9a-fA-F]+)\s+([0-9a-fA-F]+)', line)
00072         if m and int(m.group(1), 16) == range:
00073             length += 1
00074     return length
00075 
00076 def main(bin, compilation_unit):
00077     p = subprocess.Popen(['objdump', '-W', bin], stdout = subprocess.PIPE, stderr = subprocess.PIPE)
00078     (out, err) = p.communicate()
00079     sections = re.split('\n(Contents of the|The section) ', out)
00080     debug_info = [s for s in sections if s.startswith('.debug_info')]
00081     debug_ranges = [s for s in sections if s.startswith('.debug_ranges')]
00082     if not debug_ranges or not debug_info:
00083         return 0
00084 
00085     range = get_range_for(compilation_unit, debug_info[0])
00086     if range is not None:
00087         return get_range_length(range, debug_ranges[0])
00088 
00089     return -1
00090 
00091 
00092 if __name__ == '__main__':
00093     print main(*sys.argv[1:])