def __getitem__(self, name):
hash = 5381
for c in name:
hash = hash * 33 + c & bitmask(32)
word = hash // self.maskword_bits % self.header['maskwords']
self.stream.seek(self.filter + word * self.maskword_size)
word = struct_parse(self.Maskword, self.stream)
mask = 1 << hash % self.maskword_bits
mask |= 1 << (hash >> self.header['shift2']) % self.maskword_bits
if ~word & mask:
raise KeyError(name)
self.stream.seek(self.buckets + hash % self.header['nbuckets'] * 4)
bucket = struct_parse(self.Elf_word(None), self.stream)
if not bucket:
raise KeyError(name)
while True:
offset = self.values + (bucket - self.header['symndx']) * 4
value = struct_parse(self.Elf_word(None), self.stream,
stream_pos=offset)
if value & ~1 == hash & ~1:
sym = self.symtab[bucket]
if sym.name == name:
return sym
if value & 1:
raise KeyError(name)
bucket += 1
def parse_macro_section(elf, dwarf, section):
header_struct = create_header_struct(elf, dwarf)
section.stream.seek(section['sh_offset'])
header = struct_parse(header_struct, section.stream)
yield header
entry_struct = create_entry_struct(elf, dwarf, header.flags)
while section.stream.tell() - section['sh_offset'] < section['sh_size']:
yield struct_parse(entry_struct, section.stream)
def line_program_for_CU(self, cu):
top_DIE = cu.get_top_DIE()
if 'DW_AT_stmt_list' in top_DIE.attributes:
stm = self.linestream
stm.seek(top_DIE.attributes['DW_AT_stmt_list'].value, 0)
structs = self.structs
len = struct_parse(structs.Dwarf_uint32(''), stm)
pc = struct_parse(structs.Dwarf_target_addr(''), stm)
return LineTableV1(stm, structs, len, pc)
else:
return None
def __iter__(self):
for offset in range(self.buckets, self.values, 4):
self.stream.seek(offset)
bucket = struct_parse(self.Elf_word(None), self.stream)
if not bucket:
continue
sym = self.symtab[bucket]
while True:
offset = self.values + (bucket - self.header['symndx']) * 4
value = struct_parse(self.Elf_word(None), self.stream,
stream_pos=offset)
yield self.symtab[bucket]
if value & 1:
break
bucket += 1
def __iter__(self):
end = self.chain + self.header['nchain'] * 4
for offset in range(self.buckets, end, 4):
self.stream.seek(offset)
sym = struct_parse(self.Elf_word(None), self.stream)
if sym:
yield self.symtab[sym]
def compute_relocation(elffile, reloc, symtab):
if reloc['r_info_sym'] >= symtab.num_symbols():
raise ELFRelocationError(
'Invalid symbol reference in relocation: index %s' %
(reloc['r_info_sym']))
sym_value = symtab.get_symbol(reloc['r_info_sym'])['st_value']
reloc_type = reloc['r_info_type']
recipe = None
if elffile.get_machine_arch() == 'x86':
if reloc.is_RELA():
raise ELFRelocationError('Unexpected RELA relocation for x86: %s' %
reloc)
recipe = _RELOCATION_RECIPES_X86.get(reloc_type, None)
elif elffile.get_machine_arch() == 'x64':
if not reloc.is_RELA():
raise ELFRelocationError('Unexpected REL relocation for x64: %s' %
reloc)
recipe = _RELOCATION_RECIPES_X64.get(reloc_type, None)
elif elffile.get_machine_arch() == 'MIPS':
if reloc.is_RELA():
raise ELFRelocationError(
'Unexpected RELA relocation for MIPS: %s' % reloc)
recipe = _RELOCATION_RECIPES_MIPS.get(reloc_type, None)
if recipe is None:
raise ELFRelocationError('Unsupported relocation type: %s' %
reloc_type)
# So now we have everything we need to actually perform the relocation.
# Let's get to it:
# 0. Find out which struct we're going to be using to read this value
# from the stream and write it back.
if recipe.bytesize == 4:
value_struct = elffile.structs.Elf_word('')
elif recipe.bytesize == 8:
value_struct = elffile.structs.Elf_word64('')
else:
raise ELFRelocationError('Invalid bytesize %s for relocation' %
recipe.bytesize)
# 1. Read the value from the stream (with correct size and endianness)
original_value = struct_parse(value_struct,
elffile.stream,
stream_pos=reloc['r_offset'])
# 2. Apply the relocation to the value, acting according to the recipe
relocated_value = recipe.calc_func(
value=original_value,
sym_value=sym_value,
offset=reloc['r_offset'],
addend=reloc['r_addend'] if recipe.has_addend else 0)
# 3. Return reolcation as a tuple
# Make sure the relocated value fits back by wrapping it around. This
# looks like a problem, but it seems to be the way this is done in
# binutils too.
relocated_value = relocated_value % (2**(recipe.bytesize * 8))
return (reloc['r_offset'], relocated_value)
def _parse_call_site_entry(self, encoding):
base_encoding = encoding & 0x0f
modifier = encoding & 0xf0
# header
s = struct_parse(
Struct(
'CallSiteEntry',
self._formats[base_encoding]('cs_start'),
self._formats[base_encoding]('cs_len'),
self._formats[base_encoding]('cs_lp'),
self.entry_structs.Dwarf_uleb128('cs_action'),
), self.stream)
cs_start = s['cs_start']
cs_len = s['cs_len']
cs_lp = s['cs_lp']
cs_action = s['cs_action']
if modifier == 0:
pass
else:
raise NotImplementedError(
"Unsupported modifier for CallSiteEntry: %#x." % modifier)
return CallSiteEntry(cs_start, cs_len, cs_lp, cs_action)
def parse_expr(self, expr):
stm = BytesIO(bytelist2string(expr))
parsed = []
while True:
# Get the next opcode from the stream. If nothing is left in the
# stream, we're done.
byte = stm.read(1)
if len(byte) == 0:
break
# Decode the opcode and its name.
op = ord(byte)
op_name = DW_OP_opcode2name.get(op, 'OP:0x%x' % op)
if op <= 4 or op == 0x80:
args = [
struct_parse(self.structs.Dwarf_target_addr(''), stm),
]
else:
args = []
parsed.append(DWARFExprOp(op=op, op_name=op_name, args=args))
return parsed
def __init__(self, stm, cu, di):
self.cu = cu
self.dwarfinfo = di
self.stream = stm
self.offset = stm.tell()
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
structs = self.dwarfinfo.structs
self.size = struct_parse(structs.Dwarf_uint32(''), stm)
if self.size < 8:
self.tag = 'DW_TAG_padding'
self.has_children = False
else:
tag_code = struct_parse(structs.Dwarf_uint16(''), stm)
if tag_code not in TAG_reverse:
raise ValueError("%d not a known tag" % (tag_code))
self.tag = TAG_reverse[tag_code]
while stm.tell() < self.offset + self.size:
attr_offset = self.stream.tell()
attr = struct_parse(structs.Dwarf_uint16(''), stm)
form = FORM_reverse[attr & 0xf]
attr >>= 4
if attr in ATTR_reverse:
name = ATTR_reverse[attr]
elif 0x200 <= attr <= 0x3ff: #DW_AT_MIPS represented as 0x204???
name = 'DW_AT_user_0x%x' % attr
else:
raise ValueError("%d not a known attribute" % (attr))
raw_value = struct_parse(structs.Dwarf_dw_form[form], stm)
value = raw_value
self.attributes[name] = AttributeValue(name=name,
form=form,
value=value,
raw_value=raw_value,
offset=attr_offset)
self.has_children = self.attributes[
'DW_AT_sibling'].value >= self.offset + self.size + 8
def _parse_lsda_header(self):
# lpstart
lpstart_encoding = self.stream.read(1)[0]
if lpstart_encoding != DW_EH_encoding_flags['DW_EH_PE_omit']:
base_encoding = lpstart_encoding & 0x0f
modifier = lpstart_encoding & 0xf0
lpstart = struct_parse(
Struct('dummy', self._formats[base_encoding]('LPStart')),
self.stream)['LPStart']
if modifier == 0:
pass
elif modifier == DW_EH_encoding_flags['DW_EH_PE_pcrel']:
lpstart += self.address + (self.stream.tell() -
self.base_offset)
else:
raise NotImplementedError("Unsupported modifier %#x." %
modifier)
else:
lpstart = None
# ttype
ttype_encoding = self.stream.read(1)[0]
if ttype_encoding != DW_EH_encoding_flags['DW_EH_PE_omit']:
ttype_offset = struct_parse(
Struct('dummy', self.entry_structs.Dwarf_uleb128('TType')),
self.stream)['TType']
else:
ttype_offset = None
# call site table length
cstable_encoding = self.stream.read(1)[0]
cstable_length = struct_parse(
Struct('dummy', self.entry_structs.Dwarf_uleb128('CSTable')),
self.stream)['CSTable']
return ExceptionTableHeader(
lpstart,
ttype_encoding,
ttype_offset,
cstable_encoding,
cstable_length,
)
def __init__(self, elf, *pos, **kw):
BaseHash.__init__(self, elf, *pos, **kw)
self.Elf_word = elf.structs.Elf_word
self.header = Struct('Hash table header',
self.Elf_word('nbucket'), self.Elf_word('nchain'))
self.header = struct_parse(self.header, self.stream)
self.buckets = self.stream.tell()
self.chain = self.buckets + self.header['nbucket'] * 4
def _iter_verneed(self, offset):
[num] = self.entries["DT_VERNEEDNUM"]
Elf_Verneed = self.elf.structs.Elf_Verneed
for _ in range(num):
entry = struct_parse(Elf_Verneed, self.elf.stream, offset)
aux_offset = offset + entry["vn_aux"]
versions = self._file_versions(aux_offset, entry["vn_cnt"])
yield (self.strtab[entry["vn_file"]], versions)
offset += entry["vn_next"]
def __getitem__(self, sym):
"""Get Symbol() object for given table index"""
self.stream.seek(self.offset + sym * self.entsize)
entry = struct_parse(self.Elf_Sym, self.stream)
name = entry['st_name']
if name:
name = self.stringtable[name]
else:
name = None
return Symbol(entry, name)
def __parse_files_info(self, dwarf_info, structs, offset=0):
files = {}
lineprog_header = struct_parse(structs.Dwarf_lineprog_header,
dwarf_info.debug_line_sec.stream,
offset)
for i, entry in enumerate(lineprog_header.file_entry):
files[i + 1] = File(
id=i + 1,
name=entry.name,
directory=lineprog_header.include_directory[entry.dir_index -
1])
return files
def get_entries(self):
if self._decoded_entries is None:
stm = self.stm
offset = stm.tell()
end_offset = offset + self.len
structs = self.structs
entries = []
pc = self.pc
while offset < end_offset:
line = struct_parse(structs.Dwarf_uint32(''), stm)
col = struct_parse(structs.Dwarf_uint16(''), stm)
pc_delta = struct_parse(structs.Dwarf_uint32(''), stm)
if line == 0:
break
state = LineState(True)
state.file = 0
state.line = line
state.column = col if col != 0xffff else None
state.address = pc
entries.append(LineProgramEntry(0, False, [], state))
pc += pc_delta
self._decoded_entries = entries
return self._decoded_entries
def version_definitions(self):
offset = self.entries["DT_VERDEF"]
if not offset:
return
[offset] = offset
offset = self.segments.map(offset)
[num] = self.entries["DT_VERDEFNUM"]
Elf_Verdef = self.elf.structs.Elf_Verdef
for _ in range(num):
entry = struct_parse(Elf_Verdef, self.elf.stream, offset)
aux_offset = offset + entry["vd_aux"]
names = self._version_names(aux_offset, entry["vd_cnt"])
definition = Version(entry, next(names))
yield (definition, names)
offset += entry["vd_next"]
def __getitem__(self, name):
hash = 0
for c in name:
hash = (hash << 4) + c
hash = (hash ^ hash >> 24 & 0xF0) & bitmask(28)
self.stream.seek(self.buckets + hash % self.header['nbucket'] * 4)
while True:
index = struct_parse(self.Elf_word(None), self.stream)
if not index:
raise KeyError(name)
sym = self.symtab[index]
if sym.name == name:
return sym
self.stream.seek(self.chain + index * 4)
def __init__(self, elf, *pos, **kw):
BaseHash.__init__(self, elf, *pos, **kw)
self.Elf_word = elf.structs.Elf_word
self.Maskword = elf.structs.Elf_xword("Maskword")
self.header = Struct('GNU hash table header',
self.Elf_word('nbuckets'),
self.Elf_word('symndx'),
self.Elf_word('maskwords'),
self.Elf_word('shift2'),
)
self.header = struct_parse(self.header, self.stream)
self.filter = self.stream.tell()
self.maskword_size = self.Maskword.sizeof()
self.maskword_bits = self.maskword_size * 8
self.buckets = (self.filter +
self.header['maskwords'] * self.maskword_size)
self.values = self.buckets + self.header['nbuckets'] * 4
def iter_notes(self):
""" Iterates the list of notes in the segment.
"""
offset = self['p_offset']
end = self['p_offset'] + self['p_filesz']
while offset < end:
note = struct_parse(self.elffile.structs.Elf_Nhdr,
self.stream,
stream_pos=offset)
note['n_offset'] = offset
offset += self.elffile.structs.Elf_Nhdr.sizeof()
self.stream.seek(offset)
# n_namesz is 4-byte aligned.
disk_namesz = roundup(note['n_namesz'], 2)
note['n_name'] = bytes2str(
CString('').parse(self.stream.read(disk_namesz)))
offset += disk_namesz
desc_data = bytes2str(self.stream.read(note['n_descsz']))
note['n_desc'] = desc_data
offset += roundup(note['n_descsz'], 2)
note['n_size'] = offset - note['n_offset']
yield note
def iter_notes(self):
""" Iterates the list of notes in the segment.
"""
offset = self['p_offset']
end = self['p_offset'] + self['p_filesz']
while offset < end:
note = struct_parse(
self._elfstructs.Elf_Nhdr,
self.stream,
stream_pos=offset)
note['n_offset'] = offset
offset += self._elfstructs.Elf_Nhdr.sizeof()
self.stream.seek(offset)
# n_namesz is 4-byte aligned.
disk_namesz = roundup(note['n_namesz'], 2)
note['n_name'] = bytes2str(
CString('').parse(self.stream.read(disk_namesz)))
offset += disk_namesz
desc_data = bytes2str(self.stream.read(note['n_descsz']))
note['n_desc'] = desc_data
offset += roundup(note['n_descsz'], 2)
note['n_size'] = offset - note['n_offset']
yield note
def rel_table_entries(self, entries, size, type):
(entsize, Struct) = {
"DT_RELA": ("DT_RELAENT", self.elf.structs.Elf_Rela),
"DT_REL": ("DT_RELENT", self.elf.structs.Elf_Rel),
}[type]
(table,) = entries
(size,) = self.entries[size]
(entsize,) = self.entries[entsize]
table = self.segments.map(table, size)
if entsize < Struct.sizeof():
msg = "{} entry size too small: {}"
raise NotImplementedError(msg.format(Struct.name, entsize))
if size % entsize:
msg = "{} table size: {}"
raise NotImplementedError(msg.format(Struct.name, size))
# TODO: mmap
# TODO: read rel table in one go
for offset in range(table, table + size, entsize):
self.elf.stream.seek(offset)
entry = struct_parse(Struct, self.elf.stream)
yield Relocation(entry, self.elf)
def _parse_lsda_header(self):
# https://www.airs.com/blog/archives/464
self.elf.seek(self.lsda_offset)
lpstart_raw = self.elf.read(1)[0]
lpstart = None
if lpstart_raw != DW_EH_encoding_flags['DW_EH_PE_omit']:
# See https://www.airs.com/blog/archives/460, it should be omit in
# practice
raise Exception("We do not handle this case for now")
base_encoding = lpstart_raw & 0x0F
modifier = lpstart_raw & 0xF0
lpstart = struct_parse(
Struct('dummy', self._formats[base_encoding]('LPStart')),
self.elf)['LPStart']
if modifier == 0:
pass
elif modifier == DW_EH_encoding_flags['DW_EH_PE_pcrel']:
lpstart += self.address + (self.elf.tell() - self.base_offset)
else:
raise Exception("what")
typetable_encoding = self.elf.read(1)[0]
typetable_offset = None
# NOW TODO : the encoding is the right one + 1, which is weird
self.typetable_offset = 0
if typetable_encoding != DW_EH_encoding_flags['DW_EH_PE_omit']:
self.typetable_offset = struct_parse(
Struct('dummy', self.entry_structs.Dwarf_uleb128('TType')),
self.elf)['TType']
self.typetable_offset_present = True
else:
self.typetable_offset_present = False
call_site_table_encoding = self.elf.read(1)[0]
call_site_table_len = struct_parse(
Struct('dummy', self.entry_structs.Dwarf_uleb128('CSTable')),
self.elf)['CSTable']
if self.typetable_offset_present == False:
self.typetable_offset = call_site_table_len
print("lpstart", lpstart_raw)
print("lpstart_pcrel", lpstart)
print("typetable_encoding", typetable_encoding)
print("call_site_table_encoding", call_site_table_encoding)
print("CALL SITE TABLE LENGTH %d" % call_site_table_len)
print("TYPETABLE OFFSET %d" % self.typetable_offset)
self.end_label = ".LLSDATT%x" % self.fstart
self.table_label = ".LLSDATTD%x" % self.fstart
self.action_label = ".LLSDACSE%x" % self.fstart
self.callsite_label = ".LLSDACSB%x" % self.fstart
self.ttable_prefix_label = ".LLSDATYP%x" % self.fstart
# Need to construct some representation here.
self.header = {
"lpstart": lpstart_raw,
"encoding": call_site_table_encoding,
"typetable_encoding": typetable_encoding,
"call_site_table_len": call_site_table_len,
"cs_act_tt_total_len": self.
typetable_offset, # Don't forget to check typetable_offset_present
}
def ParseELFSymbols(elf):
"""Parses list of symbols in an ELF file.
Args:
elf: An elffile.ELFFile instance.
Returns:
A 2-tuple of (imported, exported) symbols. |imported| is a set of strings
of undefined symbols. |exported| is a dict where the keys are defined
symbols and the values are 3-tuples (st_info_bind, st_size, st_shndx) with
the details of the corresponding exported symbol. Note that for imported
symbols this information is always ('STB_GLOBAL', 0, 'SHN_UNDEF') and thus
not included in the result.
"""
imp = set()
exp = dict()
if elf.header.e_type not in ('ET_DYN', 'ET_EXEC'):
return imp, exp
for segment in elf.iter_segments():
if segment.header.p_type != 'PT_DYNAMIC':
continue
# Find strtab and symtab virtual addresses.
strtab_ptr = None
symtab_ptr = None
symbol_size = elf.structs.Elf_Sym.sizeof()
for tag in segment.iter_tags():
if tag.entry.d_tag == 'DT_SYMTAB':
symtab_ptr = tag.entry.d_ptr
if tag.entry.d_tag == 'DT_STRTAB':
strtab_ptr = tag.entry.d_ptr
if tag.entry.d_tag == 'DT_SYMENT':
assert symbol_size == tag.entry.d_val
stringtable = segment._get_stringtable() # pylint: disable=W0212
symtab_offset = next(elf.address_offsets(symtab_ptr))
# Assume that symtab ends right before strtab.
# This is the same assumption that glibc makes in dl-addr.c.
# The first symbol is always local undefined, unnamed so we ignore it.
for i in range(1, (strtab_ptr - symtab_ptr) / symbol_size):
symbol_offset = symtab_offset + (i * symbol_size)
symbol = utils.struct_parse(elf.structs.Elf_Sym, elf.stream,
symbol_offset)
if symbol['st_info']['bind'] == 'STB_LOCAL':
# Ignore local symbols.
continue
symbol_name = stringtable.get_string(symbol.st_name)
if symbol['st_shndx'] == 'SHN_UNDEF':
if symbol['st_info']['bind'] == 'STB_GLOBAL':
# Global undefined --> required symbols.
# We ignore weak undefined symbols.
imp.add(symbol_name)
elif symbol['st_other']['visibility'] == 'STV_DEFAULT':
# Exported symbols must have default visibility.
st_shndx = SH_TYPE_VALUES.get(symbol['st_shndx'], symbol['st_shndx'])
exp[symbol_name] = (symbol['st_info']['bind'], symbol['st_size'],
st_shndx)
return imp, exp
def ParseELFSymbols(elf):
"""Parses list of symbols in an ELF file.
Args:
elf: An elffile.ELFFile instance.
Returns:
A 2-tuple of (imported, exported) symbols. |imported| is a set of strings
of undefined symbols. |exported| is a dict where the keys are defined
symbols and the values are 3-tuples (st_info_bind, st_size, st_shndx) with
the details of the corresponding exported symbol. Note that for imported
symbols this information is always ('STB_GLOBAL', 0, 'SHN_UNDEF') and thus
not included in the result.
"""
imp = set()
exp = dict()
if elf.header.e_type not in ('ET_DYN', 'ET_EXEC'):
return imp, exp
for segment in elf.iter_segments():
if segment.header.p_type != 'PT_DYNAMIC':
continue
# Find strtab and symtab virtual addresses.
strtab_ptr = None
symtab_ptr = None
symbol_size = elf.structs.Elf_Sym.sizeof()
for tag in segment.iter_tags():
if tag.entry.d_tag == 'DT_SYMTAB':
symtab_ptr = tag.entry.d_ptr
if tag.entry.d_tag == 'DT_STRTAB':
strtab_ptr = tag.entry.d_ptr
if tag.entry.d_tag == 'DT_SYMENT':
assert symbol_size == tag.entry.d_val
stringtable = segment._get_stringtable() # pylint: disable=W0212
symtab_offset = next(elf.address_offsets(symtab_ptr))
# Assume that symtab ends right before strtab.
# This is the same assumption that glibc makes in dl-addr.c.
# The first symbol is always local undefined, unnamed so we ignore it.
for i in range(1, (strtab_ptr - symtab_ptr) / symbol_size):
symbol_offset = symtab_offset + (i * symbol_size)
symbol = utils.struct_parse(elf.structs.Elf_Sym, elf.stream,
symbol_offset)
if symbol['st_info']['bind'] == 'STB_LOCAL':
# Ignore local symbols.
continue
symbol_name = stringtable.get_string(symbol.st_name)
if symbol['st_shndx'] == 'SHN_UNDEF':
if symbol['st_info']['bind'] == 'STB_GLOBAL':
# Global undefined --> required symbols.
# We ignore weak undefined symbols.
imp.add(symbol_name)
elif symbol['st_other']['visibility'] == 'STV_DEFAULT':
# Exported symbols must have default visibility.
st_shndx = SH_TYPE_VALUES.get(symbol['st_shndx'],
symbol['st_shndx'])
exp[symbol_name] = (symbol['st_info']['bind'],
symbol['st_size'], st_shndx)
return imp, exp
def ParseELFSymbols(elf):
"""Parses list of symbols in an ELF file.
Args:
elf: An elffile.ELFFile instance.
Returns:
A 2-tuple of (imported, exported) symbols, each of which is a set.
"""
imp = set()
exp = set()
if elf.header.e_type not in ('ET_DYN', 'ET_EXEC'):
return imp, exp
for segment in elf.iter_segments():
if segment.header.p_type != 'PT_DYNAMIC':
continue
# Find strtab and symtab virtual addresses.
symtab_ptr = None
dthash_ptr = None
symbol_size = elf.structs.Elf_Sym.sizeof()
for tag in segment.iter_tags():
if tag.entry.d_tag == 'DT_SYMTAB':
symtab_ptr = tag.entry.d_ptr
if tag.entry.d_tag == 'DT_SYMENT':
assert symbol_size == tag.entry.d_val
if tag.entry.d_tag == 'DT_HASH':
dthash_ptr = tag.entry.d_ptr
stringtable = segment._get_stringtable() # pylint: disable=protected-access
symtab_offset = next(elf.address_offsets(symtab_ptr))
if dthash_ptr:
# DT_SYMTAB provides no information on the number of symbols table
# entries. Instead, we use DT_HASH's nchain value, which according to the
# spec, "should equal the number of symbol table entries".
# nchain is the second 32-bit integer at the address pointed by DT_HASH,
# both for ELF and ELF64 formats.
fmt = '<I' if elf.little_endian else '>I'
elf.stream.seek(dthash_ptr + 4)
nsymbols = struct.unpack(fmt, elf.stream.read(4))[0]
else:
# Get the size of DYNSYM section from section header.
symtab_size = int(GetSymbolTableSize(elf))
nsymbols = symtab_size // symbol_size
# The first symbol is always local undefined, unnamed so we ignore it.
for i in range(1, nsymbols):
symbol_offset = symtab_offset + (i * symbol_size)
symbol = utils.struct_parse(elf.structs.Elf_Sym, elf.stream,
symbol_offset)
if symbol['st_info']['bind'] == 'STB_LOCAL':
# Ignore local symbols.
continue
symbol_name = stringtable.get_string(symbol.st_name)
if symbol['st_shndx'] == 'SHN_UNDEF':
if symbol['st_info']['bind'] == 'STB_GLOBAL':
# Global undefined --> required symbols.
# We ignore weak undefined symbols.
imp.add(symbol_name)
elif symbol['st_other']['visibility'] == 'STV_DEFAULT':
# Exported symbols must have default visibility.
exp.add(symbol_name)
return imp, exp
def _parse_lsda_entries(self):
start_cs_offset = self.elf.tell()
action_count = 0
while self.elf.tell(
) - start_cs_offset < self.header["call_site_table_len"]:
base_encoding = self.header["encoding"] & 0x0f
modifier = self.header["encoding"] & 0xf0
# Maybe we need to store the offset in the entry ?
# header
s = struct_parse(
Struct(
'CallSiteEntry',
self._formats[base_encoding]('cs_start'),
self._formats[base_encoding]('cs_len'),
self._formats[base_encoding]('cs_lp'),
self.entry_structs.Dwarf_uleb128('cs_action'),
), self.elf)
cs_action = s['cs_action']
if cs_action != 0:
action_offset_bytes = (cs_action + 1) >> 1
action_count = max(action_count, action_offset_bytes)
self.entries.append(s)
processed_bytes = self.elf.tell() - start_cs_offset
print("+++++ %d bytes read, %d to go, %d actions" %
(processed_bytes, self.typetable_offset - processed_bytes,
action_count))
idx = action_count
processed_action_count = 0
while idx > 0:
action = struct_parse(
Struct("ActionEntry",
self.entry_structs.Dwarf_uint8('act_filter'),
self.entry_structs.Dwarf_uint8('act_next')), self.elf)
print(">>>> ACTION ", action)
self.actions.append(action)
processed_action_count = processed_action_count + 1
idx -= 1
ttendloc = self.lsda_offset + self.typetable_offset + 3
print("TT %x" % (ttendloc))
for action in self.actions:
type_bytes_offset = (action.act_filter * -8)
ttentryloc = ttendloc + type_bytes_offset
print("****** TT LOC: %x" % (ttentryloc))
self.elf.seek(ttentryloc, io.SEEK_SET)
ptrbytes = self.elf.read(8)
ptr = struct.unpack("<Q", ptrbytes)[0]
print("****** TT PTR: %x" % ptr)
symbolized_target = 0
if ptr != 0:
symbolized_target = ptr + ttentryloc
typeentry = {'address': symbolized_target}
self.ttentries[action.act_filter] = typeentry
print("****** TT x: %x" % (symbolized_target))
def _file_versions(self, offset, cnt):
Elf_Vernaux = self.elf.structs.Elf_Vernaux
for _ in range(cnt):
entry = struct_parse(Elf_Vernaux, self.elf.stream, offset)
yield VersionAuxiliary(entry, self.strtab[entry["vna_name"]])
offset += entry["vna_next"]
def _version_names(self, offset, cnt):
Elf_Verdaux = self.elf.structs.Elf_Verdaux
for _ in range(cnt):
entry = struct_parse(Elf_Verdaux, self.elf.stream, offset)
yield self.strtab[entry["vda_name"]]
offset += entry["vda_next"]
