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 pyelftools is not installed, the example can also run from the root or
  13 # examples/ dir of the source distribution.
  14 sys.path[0:0] = ['.', '..']
  15
  16 from elftools.common.py3compat import bytes2str
  17 from elftools.elf.elffile import ELFFile
  18
  19
  20 def process_file(filename):
  21     print('Processing file:', filename)
  22     with open(filename, 'rb') as f:
  23         elffile = ELFFile(f)
  24
  25         if not elffile.has_dwarf_info():
  26             print('  file has no DWARF info')
  27             return
  28
  29         # get_dwarf_info returns a DWARFInfo context object, which is the
  30         # starting point for all DWARF-based processing in pyelftools.
  31         dwarfinfo = elffile.get_dwarf_info()
  32
  33         for CU in dwarfinfo.iter_CUs():
  34             # DWARFInfo allows to iterate over the compile units contained in
  35             # the .debug_info section. CU is a CompileUnit object, with some
  36             # computed attributes (such as its offset in the section) and
  37             # a header which conforms to the DWARF standard. The access to
  38             # header elements is, as usual, via item-lookup.
  39             print('  Found a compile unit at offset %s, length %s' % (
  40                 CU.cu_offset, CU['unit_length']))
  41
  42             # The first DIE in each compile unit describes it.
  43             top_DIE = CU.get_top_DIE()
  44             print('    Top DIE with tag=%s' % top_DIE.tag)
  45
  46             # Each DIE holds an OrderedDict of attributes, mapping names to
  47             # values. Values are represented by AttributeValue objects in
  48             # elftools/dwarf/die.py
  49             # We're interested in the DW_AT_name attribute. Note that its value
  50             # is usually a string taken from the .debug_str section. This
  51             # is done transparently by the library, and such a value will be
  52             # simply given as a string.
  53             name_attr = top_DIE.attributes['DW_AT_name']
  54             print('    name=%s' % bytes2str(name_attr.value))
  55
  56 if __name__ == '__main__':
  57     for filename in sys.argv[1:]:
  58         process_file(filename)
  59
  60
  61
  62
  63