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.elf.elffile import ELFFile
  20
  21
  22 def process_file(filename):
  23     print('Processing file:', filename)
  24     with open(filename, 'rb') as f:
  25         elffile = ELFFile(f)
  26
  27         if not elffile.has_dwarf_info():
  28             print('  file has no DWARF info')
  29             return
  30
  31         # get_dwarf_info returns a DWARFInfo context object, which is the
  32         # starting point for all DWARF-based processing in pyelftools.
  33         dwarfinfo = elffile.get_dwarf_info()
  34
  35         for CU in dwarfinfo.iter_CUs():
  36             # DWARFInfo allows to iterate over the compile units contained in
  37             # the .debug_info section. CU is a CompileUnit object, with some
  38             # computed attributes (such as its offset in the section) and
  39             # a header which conforms to the DWARF standard. The access to
  40             # header elements is, as usual, via item-lookup.
  41             print('  Found a compile unit at offset %s, length %s' % (
  42                 CU.cu_offset, CU['unit_length']))
  43
  44             # The first DIE in each compile unit describes it.
  45             top_DIE = CU.get_top_DIE()
  46             print('    Top DIE with tag=%s' % top_DIE.tag)
  47
  48             # Each DIE holds an OrderedDict of attributes, mapping names to
  49             # values. Values are represented by AttributeValue objects in
  50             # elftools/dwarf/die.py
  51             # We're interested in the DW_AT_name attribute. Note that its value
  52             # is usually a string taken from the .debug_str section. This
  53             # is done transparently by the library, and such a value will be
  54             # simply given as a string.
  55             name_attr = top_DIE.attributes['DW_AT_name']
  56             print('    name=%s' % name_attr.value)
  57
  58 if __name__ == '__main__':
  59     for filename in sys.argv[1:]:
  60         process_file(filename)
  61
  62
  63
  64
  65