elftools/elf/notes.py

   1 #-------------------------------------------------------------------------------
   2 # elftools: elf/notes.py
   3 #
   4 # ELF notes
   5 #
   6 # Eli Bendersky (eliben@gmail.com)
   7 # This code is in the public domain
   8 #-------------------------------------------------------------------------------
   9 from ..common.utils import struct_parse, bytes2hex, roundup, bytes2str
  10 from ..construct import CString
  11
  12
  13 def iter_notes(elffile, offset, size):
  14     """ Yield all the notes in a section or segment.
  15     """
  16     end = offset + size
  17     while offset < end:
  18         note = struct_parse(
  19             elffile.structs.Elf_Nhdr,
  20             elffile.stream,
  21             stream_pos=offset)
  22         note['n_offset'] = offset
  23         offset += elffile.structs.Elf_Nhdr.sizeof()
  24         elffile.stream.seek(offset)
  25         # n_namesz is 4-byte aligned.
  26         disk_namesz = roundup(note['n_namesz'], 2)
  27         note['n_name'] = bytes2str(
  28             CString('').parse(elffile.stream.read(disk_namesz)))
  29         offset += disk_namesz
  30
  31         desc_data = elffile.stream.read(note['n_descsz'])
  32         note['n_descdata'] = desc_data
  33         if note['n_type'] == 'NT_GNU_ABI_TAG':
  34             note['n_desc'] = struct_parse(elffile.structs.Elf_abi,
  35                                           elffile.stream,
  36                                           offset)
  37         elif note['n_type'] == 'NT_GNU_BUILD_ID':
  38             note['n_desc'] = bytes2hex(desc_data)
  39         elif note['n_type'] == 'NT_GNU_GOLD_VERSION':
  40             note['n_desc'] = bytes2str(desc_data)
  41         elif note['n_type'] == 'NT_PRPSINFO':
  42             note['n_desc'] = struct_parse(elffile.structs.Elf_Prpsinfo,
  43                                           elffile.stream,
  44                                           offset)
  45         elif note['n_type'] == 'NT_FILE':
  46             note['n_desc'] = struct_parse(elffile.structs.Elf_Nt_File,
  47                                           elffile.stream,
  48                                           offset)
  49         elif note['n_type'] == 'NT_GNU_PROPERTY_TYPE_0':
  50             off = offset
  51             props = []
  52             while off < end:
  53                 p = struct_parse(elffile.structs.Elf_Prop, elffile.stream, off)
  54                 off += roundup(p.pr_datasz + 8, 2 if elffile.elfclass == 32 else 3)
  55                 props.append(p)
  56             note['n_desc'] = props
  57         else:
  58             note['n_desc'] = desc_data
  59         offset += roundup(note['n_descsz'], 2)
  60         note['n_size'] = offset - note['n_offset']
  61         yield note