blob: a62ef169dc894717f33087a882549546908fb1cc [file] [log] [blame]
# elftools: elf/
# ELF Dynamic Tags
# Mike Frysinger (
# This code is in the public domain
import itertools
from .sections import Section
from .segments import Segment
from ..common.utils import struct_parse
from .enums import ENUM_D_TAG
class DynamicTag(object):
""" Dynamic Tag object - representing a single dynamic tag entry from a
dynamic section.
Allows dictionary-like access to the dynamic structure. For special
tags (those listed in the _HANDLED_TAGS set below), creates additional
attributes for convenience. For example, .soname will contain the actual
value of DT_SONAME (fetched from the dynamic symbol table).
_HANDLED_TAGS = frozenset(
def __init__(self, entry, elffile):
self.entry = entry
if entry.d_tag in self._HANDLED_TAGS:
dynstr = elffile.get_section_by_name(b'.dynstr')
setattr(self, entry.d_tag[3:].lower(),
def __getitem__(self, name):
""" Implement dict-like access to entries
return self.entry[name]
def __repr__(self):
return '<DynamicTag (%s): %r>' % (self.entry.d_tag, self.entry)
def __str__(self):
if self.entry.d_tag in self._HANDLED_TAGS:
s = '"%s"' % getattr(self, self.entry.d_tag[3:].lower())
s = '%#x' % self.entry.d_ptr
return '<DynamicTag (%s) %s>' % (self.entry.d_tag, s)
class Dynamic(object):
""" Shared functionality between dynamic sections and segments.
def __init__(self, stream, elffile, position):
self._stream = stream
self._elffile = elffile
self._elfstructs = elffile.structs
self._num_tags = -1
self._offset = position
self._tagsize = self._elfstructs.Elf_Dyn.sizeof()
def iter_tags(self, type=None):
""" Yield all tags (limit to |type| if specified)
for n in itertools.count():
tag = self.get_tag(n)
if type is None or tag.entry.d_tag == type:
yield tag
if tag.entry.d_tag == 'DT_NULL':
def get_tag(self, n):
""" Get the tag at index #n from the file (DynamicTag object)
offset = self._offset + n * self._tagsize
entry = struct_parse(
return DynamicTag(entry, self._elffile)
def num_tags(self):
""" Number of dynamic tags in the file
if self._num_tags != -1:
return self._num_tags
for n in itertools.count():
tag = self.get_tag(n)
if tag.entry.d_tag == 'DT_NULL':
self._num_tags = n + 1
return self._num_tags
class DynamicSection(Section, Dynamic):
""" ELF dynamic table section. Knows how to process the list of tags.
def __init__(self, header, name, stream, elffile):
Section.__init__(self, header, name, stream)
Dynamic.__init__(self, stream, elffile, self['sh_offset'])
class DynamicSegment(Segment, Dynamic):
""" ELF dynamic table segment. Knows how to process the list of tags.
def __init__(self, header, stream, elffile):
Segment.__init__(self, header, stream)
Dynamic.__init__(self, stream, elffile, self['p_offset'])