You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
219 lines
7.3 KiB
219 lines
7.3 KiB
5 years ago
|
#-------------------------------------------------------------------------------
|
||
|
|
# elftools: dwarf/die.py
|
||
|
|
#
|
||
|
|
# DWARF Debugging Information Entry
|
||
|
|
#
|
||
|
|
# Eli Bendersky (eliben@gmail.com)
|
||
|
|
# This code is in the public domain
|
||
|
|
#-------------------------------------------------------------------------------
|
||
|
|
from collections import namedtuple, OrderedDict
|
||
|
|
import os
|
||
|
|
|
||
|
|
from ..common.exceptions import DWARFError
|
||
|
|
from ..common.py3compat import bytes2str, iteritems
|
||
|
|
from ..common.utils import struct_parse, preserve_stream_pos
|
||
|
|
from .enums import DW_FORM_raw2name
|
||
|
|
|
||
|
|
|
||
|
|
# AttributeValue - describes an attribute value in the DIE:
|
||
|
|
#
|
||
|
|
# name:
|
||
|
|
# The name (DW_AT_*) of this attribute
|
||
|
|
#
|
||
|
|
# form:
|
||
|
|
# The DW_FORM_* name of this attribute
|
||
|
|
#
|
||
|
|
# value:
|
||
|
|
# The value parsed from the section and translated accordingly to the form
|
||
|
|
# (e.g. for a DW_FORM_strp it's the actual string taken from the string table)
|
||
|
|
#
|
||
|
|
# raw_value:
|
||
|
|
# Raw value as parsed from the section - used for debugging and presentation
|
||
|
|
# (e.g. for a DW_FORM_strp it's the raw string offset into the table)
|
||
|
|
#
|
||
|
|
# offset:
|
||
|
|
# Offset of this attribute's value in the stream (absolute offset, relative
|
||
|
|
# the beginning of the whole stream)
|
||
|
|
#
|
||
|
|
AttributeValue = namedtuple(
|
||
|
|
'AttributeValue', 'name form value raw_value offset')
|
||
|
|
|
||
|
|
|
||
|
|
class DIE(object):
|
||
|
|
""" A DWARF debugging information entry. On creation, parses itself from
|
||
|
|
the stream. Each DIE is held by a CU.
|
||
|
|
|
||
|
|
Accessible attributes:
|
||
|
|
|
||
|
|
tag:
|
||
|
|
The DIE tag
|
||
|
|
|
||
|
|
size:
|
||
|
|
The size this DIE occupies in the section
|
||
|
|
|
||
|
|
offset:
|
||
|
|
The offset of this DIE in the stream
|
||
|
|
|
||
|
|
attributes:
|
||
|
|
An ordered dictionary mapping attribute names to values. It's
|
||
|
|
ordered to preserve the order of attributes in the section
|
||
|
|
|
||
|
|
has_children:
|
||
|
|
Specifies whether this DIE has children
|
||
|
|
|
||
|
|
abbrev_code:
|
||
|
|
The abbreviation code pointing to an abbreviation entry (note
|
||
|
|
that this is for informational pusposes only - this object
|
||
|
|
interacts with its abbreviation table transparently).
|
||
|
|
|
||
|
|
See also the public methods.
|
||
|
|
"""
|
||
|
|
def __init__(self, cu, stream, offset):
|
||
|
|
""" cu:
|
||
|
|
CompileUnit object this DIE belongs to. Used to obtain context
|
||
|
|
information (structs, abbrev table, etc.)
|
||
|
|
|
||
|
|
stream, offset:
|
||
|
|
The stream and offset into it where this DIE's data is located
|
||
|
|
"""
|
||
|
|
self.cu = cu
|
||
|
|
self.dwarfinfo = self.cu.dwarfinfo # get DWARFInfo context
|
||
|
|
self.stream = stream
|
||
|
|
self.offset = offset
|
||
|
|
|
||
|
|
self.attributes = OrderedDict()
|
||
|
|
self.tag = None
|
||
|
|
self.has_children = None
|
||
|
|
self.abbrev_code = None
|
||
|
|
self.size = 0
|
||
|
|
# Null DIE terminator. It can be used to obtain offset range occupied
|
||
|
|
# by this DIE including its whole subtree.
|
||
|
|
self._terminator = None
|
||
|
|
self._parent = None
|
||
|
|
|
||
|
|
self._parse_DIE()
|
||
|
|
|
||
|
|
def is_null(self):
|
||
|
|
""" Is this a null entry?
|
||
|
|
"""
|
||
|
|
return self.tag is None
|
||
|
|
|
||
|
|
def get_parent(self):
|
||
|
|
""" The parent DIE of this DIE. None if the DIE has no parent (i.e. a
|
||
|
|
top-level DIE).
|
||
|
|
"""
|
||
|
|
return self._parent
|
||
|
|
|
||
|
|
def get_full_path(self):
|
||
|
|
""" Return the full path filename for the DIE.
|
||
|
|
|
||
|
|
The filename is the join of 'DW_AT_comp_dir' and 'DW_AT_name',
|
||
|
|
either of which may be missing in practice. Note that its value is
|
||
|
|
usually a string taken from the .debug_string section and the
|
||
|
|
returned value will be a string.
|
||
|
|
"""
|
||
|
|
comp_dir_attr = self.attributes.get('DW_AT_comp_dir', None)
|
||
|
|
comp_dir = bytes2str(comp_dir_attr.value) if comp_dir_attr else ''
|
||
|
|
fname_attr = self.attributes.get('DW_AT_name', None)
|
||
|
|
fname = bytes2str(fname_attr.value) if fname_attr else ''
|
||
|
|
return os.path.join(comp_dir, fname)
|
||
|
|
|
||
|
|
def iter_children(self):
|
||
|
|
""" Iterates all children of this DIE
|
||
|
|
"""
|
||
|
|
return self.cu.iter_DIE_children(self)
|
||
|
|
|
||
|
|
def iter_siblings(self):
|
||
|
|
""" Yield all siblings of this DIE
|
||
|
|
"""
|
||
|
|
if self._parent:
|
||
|
|
for sibling in self._parent.iter_children():
|
||
|
|
if sibling is not self:
|
||
|
|
yield sibling
|
||
|
|
else:
|
||
|
|
raise StopIteration()
|
||
|
|
|
||
|
|
# The following methods are used while creating the DIE and should not be
|
||
|
|
# interesting to consumers
|
||
|
|
#
|
||
|
|
|
||
|
|
def set_parent(self, die):
|
||
|
|
self._parent = die
|
||
|
|
|
||
|
|
#------ PRIVATE ------#
|
||
|
|
|
||
|
|
def __repr__(self):
|
||
|
|
s = 'DIE %s, size=%s, has_children=%s\n' % (
|
||
|
|
self.tag, self.size, self.has_children)
|
||
|
|
for attrname, attrval in iteritems(self.attributes):
|
||
|
|
s += ' |%-18s: %s\n' % (attrname, attrval)
|
||
|
|
return s
|
||
|
|
|
||
|
|
def __str__(self):
|
||
|
|
return self.__repr__()
|
||
|
|
|
||
|
|
def _parse_DIE(self):
|
||
|
|
""" Parses the DIE info from the section, based on the abbreviation
|
||
|
|
table of the CU
|
||
|
|
"""
|
||
|
|
structs = self.cu.structs
|
||
|
|
|
||
|
|
# A DIE begins with the abbreviation code. Read it and use it to
|
||
|
|
# obtain the abbrev declaration for this DIE.
|
||
|
|
# Note: here and elsewhere, preserve_stream_pos is used on operations
|
||
|
|
# that manipulate the stream by reading data from it.
|
||
|
|
self.abbrev_code = struct_parse(
|
||
|
|
structs.Dwarf_uleb128(''), self.stream, self.offset)
|
||
|
|
|
||
|
|
# This may be a null entry
|
||
|
|
if self.abbrev_code == 0:
|
||
|
|
self.size = self.stream.tell() - self.offset
|
||
|
|
return
|
||
|
|
|
||
|
|
abbrev_decl = self.cu.get_abbrev_table().get_abbrev(self.abbrev_code)
|
||
|
|
self.tag = abbrev_decl['tag']
|
||
|
|
self.has_children = abbrev_decl.has_children()
|
||
|
|
|
||
|
|
# Guided by the attributes listed in the abbreviation declaration, parse
|
||
|
|
# values from the stream.
|
||
|
|
for name, form in abbrev_decl.iter_attr_specs():
|
||
|
|
attr_offset = self.stream.tell()
|
||
|
|
raw_value = struct_parse(structs.Dwarf_dw_form[form], self.stream)
|
||
|
|
|
||
|
|
value = self._translate_attr_value(form, raw_value)
|
||
|
|
self.attributes[name] = AttributeValue(
|
||
|
|
name=name,
|
||
|
|
form=form,
|
||
|
|
value=value,
|
||
|
|
raw_value=raw_value,
|
||
|
|
offset=attr_offset)
|
||
|
|
|
||
|
|
self.size = self.stream.tell() - self.offset
|
||
|
|
|
||
|
|
def _translate_attr_value(self, form, raw_value):
|
||
|
|
""" Translate a raw attr value according to the form
|
||
|
|
"""
|
||
|
|
value = None
|
||
|
|
if form == 'DW_FORM_strp':
|
||
|
|
with preserve_stream_pos(self.stream):
|
||
|
|
value = self.dwarfinfo.get_string_from_table(raw_value)
|
||
|
|
elif form == 'DW_FORM_flag':
|
||
|
|
value = not raw_value == 0
|
||
|
|
elif form == 'DW_FORM_flag_present':
|
||
|
|
value = True
|
||
|
|
elif form == 'DW_FORM_indirect':
|
||
|
|
try:
|
||
|
|
form = DW_FORM_raw2name[raw_value]
|
||
|
|
except KeyError as err:
|
||
|
|
raise DWARFError(
|
||
|
|
'Found DW_FORM_indirect with unknown raw_value=' +
|
||
|
|
str(raw_value))
|
||
|
|
|
||
|
|
raw_value = struct_parse(
|
||
|
|
self.cu.structs.Dwarf_dw_form[form], self.stream)
|
||
|
|
# Let's hope this doesn't get too deep :-)
|
||
|
|
return self._translate_attr_value(form, raw_value)
|
||
|
|
else:
|
||
|
|
value = raw_value
|
||
|
|
return value
|