examples/dwarf_pubnames_types.py

   1 #-------------------------------------------------------------------------------
   2 # elftools example: dwarf_pubnames_types.py
   3 #
   4 # Dump the contents of .debug_pubnames and .debug_pubtypes sections from the
   5 # ELF file.
   6 #
   7 # Note: sample_exe64.elf doesn't have a .debug_pubtypes section.
   8 #
   9 # Vijay Ramasami (rvijayc@gmail.com)
  10 # This code is in the public domain
  11 #-------------------------------------------------------------------------------
  12 from __future__ import print_function
  13 import sys
  14
  15 # If pyelftools is not installed, the example can also run from the root or
  16 # examples/ dir of the source distribution.
  17 sys.path[0:0] = ['.', '..']
  18
  19 from elftools.elf.elffile import ELFFile
  20 from elftools.common.py3compat import bytes2str
  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         # get .debug_pubtypes section.
  36         pubnames = dwarfinfo.get_pubnames()
  37         if pubnames is None:
  38             print('ERROR: No .debug_pubnames section found in ELF.')
  39         else:
  40             print('%d entries found in .debug_pubnames' % len(pubnames))
  41
  42             print('Trying pubnames example ...')
  43             for name, entry in pubnames.items():
  44                 print('%s: cu_ofs = %d, die_ofs = %d' %
  45                         (name, entry.cu_ofs, entry.die_ofs))
  46
  47                 # get the actual CU/DIE that has this information.
  48                 print('Fetching the actual die for %s ...' % name)
  49                 for cu in dwarfinfo.iter_CUs():
  50                     if cu.cu_offset == entry.cu_ofs:
  51                         for die in cu.iter_DIEs():
  52                             if die.offset == entry.die_ofs:
  53                                 print('Die Name: %s' %
  54                                         bytes2str(die.attributes['DW_AT_name'].value))
  55
  56             # dump all entries in .debug_pubnames section.
  57             print('Dumping .debug_pubnames table ...')
  58             print('-' * 66)
  59             print('%50s%8s%8s' % ('Symbol', 'CU_OFS', 'DIE_OFS'))
  60             print('-' * 66)
  61             for (name, entry) in pubnames.items():
  62                 print('%50s%8d%8d' % (name, entry.cu_ofs, entry.die_ofs))
  63             print('-' * 66)
  64
  65         # get .debug_pubtypes section.
  66         pubtypes = dwarfinfo.get_pubtypes()
  67         if pubtypes is None:
  68             print('ERROR: No .debug_pubtypes section found in ELF')
  69         else:
  70             print('%d entries found in .debug_pubtypes' % len(pubtypes))
  71
  72             for name, entry in pubtypes.items():
  73                 print('%s: cu_ofs = %d, die_ofs = %d' %
  74                         (name, entry.cu_ofs, entry.die_ofs))
  75
  76                 # get the actual CU/DIE that has this information.
  77                 print('Fetching the actual die for %s ...' % name)
  78                 for cu in dwarfinfo.iter_CUs():
  79                     if cu.cu_offset == entry.cu_ofs:
  80                         for die in cu.iter_DIEs():
  81                             if die.offset == entry.die_ofs:
  82                                 print('Die Name: %s' %
  83                                         bytes2str(die.attributes['DW_AT_name'].value))
  84                                 die_info_rec(die)
  85
  86             # dump all entries in .debug_pubtypes section.
  87             print('Dumping .debug_pubtypes table ...')
  88             print('-' * 66)
  89             print('%50s%8s%8s' % ('Symbol', 'CU_OFS', 'DIE_OFS'))
  90             print('-' * 66)
  91             for (name, entry) in pubtypes.items():
  92                 print('%50s%8d%8d' % (name, entry.cu_ofs, entry.die_ofs))
  93             print('-' * 66)
  94
  95
  96 def die_info_rec(die, indent_level='    '):
  97     """ A recursive function for showing information about a DIE and its
  98         children.
  99     """
 100     print(indent_level + 'DIE tag=%s, attrs=' % die.tag)
 101     for name, val in die.attributes.items():
 102         print(indent_level + '  %s = %s' % (name, val))
 103     child_indent = indent_level + '  '
 104     for child in die.iter_children():
 105         die_info_rec(child, child_indent)
 106
 107
 108 if __name__ == '__main__':
 109     if sys.argv[1] == '--test':
 110         process_file(sys.argv[2])
 111         sys.exit(0)
 112
 113     if len(sys.argv) < 2:
 114         print('Expected usage: {0} <executable>'.format(sys.argv[0]))
 115         sys.exit(1)
 116     process_file(sys.argv[1])