examples/examine_dwarf_info.py

   1 #-------------------------------------------------------------------------------
   2 # elftools example: examine_dwarf_info.py
   3 #
   4 # An example of examining information in the .debug_info section of an ELF file.
   5 #
   6 # Eli Bendersky (eliben@gmail.com)
   7 # This code is in the public domain
   8 #-------------------------------------------------------------------------------
   9 from __future__ import print_function
  10 import sys
  11
  12 # If elftools is not installed, maybe we're running from the root or examples
  13 # dir of the source distribution
  14 try:
  15     import elftools
  16 except ImportError:
  17     sys.path.extend(['.', '..'])
  18
  19 from elftools.common.py3compat import bytes2str
  20 from elftools.elf.elffile import ELFFile
  21
  22
  23 def process_file(filename):
  24     print('Processing file:', filename)
  25     with open(filename, 'rb') as f:
  26         elffile = ELFFile(f)
  27
  28         if not elffile.has_dwarf_info():
  29             print('  file has no DWARF info')
  30             return
  31
  32         # get_dwarf_info returns a DWARFInfo context object, which is the
  33         # starting point for all DWARF-based processing in pyelftools.
  34         dwarfinfo = elffile.get_dwarf_info()
  35
  36         for CU in dwarfinfo.iter_CUs():
  37             # DWARFInfo allows to iterate over the compile units contained in
  38             # the .debug_info section. CU is a CompileUnit object, with some
  39             # computed attributes (such as its offset in the section) and
  40             # a header which conforms to the DWARF standard. The access to
  41             # header elements is, as usual, via item-lookup.
  42             print('  Found a compile unit at offset %s, length %s' % (
  43                 CU.cu_offset, CU['unit_length']))
  44
  45             # The first DIE in each compile unit describes it.
  46             top_DIE = CU.get_top_DIE()
  47             print('    Top DIE with tag=%s' % top_DIE.tag)
  48
  49             # Each DIE holds an OrderedDict of attributes, mapping names to
  50             # values. Values are represented by AttributeValue objects in
  51             # elftools/dwarf/die.py
  52             # We're interested in the DW_AT_name attribute. Note that its value
  53             # is usually a string taken from the .debug_str section. This
  54             # is done transparently by the library, and such a value will be
  55             # simply given as a string.
  56             name_attr = top_DIE.attributes['DW_AT_name']
  57             print('    name=%s' % bytes2str(name_attr.value))
  58
  59 if __name__ == '__main__':
  60     for filename in sys.argv[1:]:
  61         process_file(filename)
  62
  63
  64
  65
  66