def cmp_func():
func_new_size = func_new_dio.get_size()
func_obj_size = func_obj_dio.get_size()
if func_new_size != func_obj_size:
raise Exception("Function {} size mismatch".format(func_new_dio))
func_size = func_new_size
reloc_map = {}
for rel_type, rel_offset, key in relocs:
reloc_map[rel_offset] = RELOC_SIZES[rel_type]
assert len(reloc_map) == len(relocs)
func_new_code = read(new_text_sec, func_new_addr, func_size)
func_obj_code = read(obj_text_sec, func_obj_addr, func_size)
next_offset = 0
for offset, (x_new,
x_obj) in enumerate(zip(func_new_code, func_obj_code)):
skip = reloc_map.get(offset)
if skip:
next_offset = offset + skip
if offset < next_offset:
continue
if x_new != x_obj:
raise Exception(
"Code mismatch for function {} at offset {}".format(
debuginfo.format_di_key(func_di_key), offset))
def get_relocs(self, check_symbol=None):
elf = self.elf
di_reloc = self.di_reloc
symtab = di_reloc.symtab
get_di_key = self.get_di_key
result = {}
def append_rel():
reloc_list.append((rel_type, rel.entry.r_offset, key))
for sec in elf.iter_sections():
if not sec.name.startswith('.rela.text'):
continue
if sec.header.sh_link != di_reloc.sym_sec_idx:
raise Exception("Symbol table mismatch")
print "== Processing", sec.name,
text_sec_idx = sec.header.sh_info
text_sec = elf.get_section(text_sec_idx)
print "=>", text_sec.name
func_di_key = get_di_key(text_sec_idx)
reloc_list = []
result[func_di_key] = (text_sec, reloc_list)
for rel in sec.iter_relocations():
rel_type = rel.entry.r_info_type
rel_size = RELOC_SIZES[rel_type]
sym = symtab.get_symbol(rel.entry.r_info_sym)
check_symbol and check_symbol(rel, sym)
sym_bind = sym.entry.st_info.bind
target_sec_idx = sym.entry.st_shndx
target_sec = elf.get_section(target_sec_idx) \
if isinstance(target_sec_idx, INT_TYPES) else None
target_sec_name = target_sec.name if target_sec else target_sec_idx
if sym_bind == STR.STB_GLOBAL:
key = key_repr = sym.name
elif sym_bind == STR.STB_LOCAL:
if not should_resolve(target_sec):
key = None
append_rel()
continue
key = get_di_key(target_sec_idx)
key_repr = debuginfo.format_di_key(key)
else:
assert 0
append_rel()
print " +{:<5d} {:40s} {}".format(rel.entry.r_offset,
target_sec_name, key_repr)
return result
def resolve(old_elf, new_elf, obj_seq):
obj_seq = list(obj_seq)
old_elf_di = debuginfo.get_debug_info(old_elf)
old_elf_cus = set(old_elf_di.get_cu_names())
new_elf_di = debuginfo.get_debug_info(new_elf)
new_elf_cus = set(new_elf_di.get_cu_names())
if not (new_elf_cus <= old_elf_cus):
print "NEW CUs", " ".join(new_elf_cus)
print "OLD CUs", " ".join(old_elf_cus)
raise Exception("CU mismatch")
obj_cus = set()
for obj in obj_seq:
obj_di = debuginfo.get_debug_info(obj)
obj_cus.update(obj_di.get_cu_names())
if new_elf_cus != obj_cus:
print "NEW CUs", " ".join(new_elf_cus)
print "OBJ CUs", " ".join(obj_cus)
raise Exception("CU mismatch")
new_text_sec = new_elf.get_section_by_name('.text')
def read(sec, addr, size):
stream = sec.stream
pos = addr - sec.header.sh_addr + sec.header.sh_offset
stream.seek(pos)
data = stream.read(size)
assert len(data) == size
return data
def read_num(sec, addr, size):
data = read(sec, addr, size)
result = 0
shift = 0
for b in data:
result += ord(b) << shift
shift += 8
return result
def sign_extend(n, low_bits, high_bits):
low_sign = 1 << (low_bits - 1)
low_lim = low_sign << 1
high_lim = 1 << high_bits
assert 0 <= n < low_lim
sign = n & low_sign
return n + high_lim - low_lim if sign else n
def get_addr(elf, key):
if isinstance(key, basestring):
symtab = get_module_symtab(elf)
sym = symtab.get_sym(key)
return sym.entry.st_value
else:
di = debuginfo.get_debug_info(elf)
return di.get_dio_by_key(key).get_addr()
def cmp_func():
func_new_size = func_new_dio.get_size()
func_obj_size = func_obj_dio.get_size()
if func_new_size != func_obj_size:
raise Exception("Function {} size mismatch".format(func_new_dio))
func_size = func_new_size
reloc_map = {}
for rel_type, rel_offset, key in relocs:
reloc_map[rel_offset] = RELOC_SIZES[rel_type]
assert len(reloc_map) == len(relocs)
func_new_code = read(new_text_sec, func_new_addr, func_size)
func_obj_code = read(obj_text_sec, func_obj_addr, func_size)
next_offset = 0
for offset, (x_new,
x_obj) in enumerate(zip(func_new_code, func_obj_code)):
skip = reloc_map.get(offset)
if skip:
next_offset = offset + skip
if offset < next_offset:
continue
if x_new != x_obj:
raise Exception(
"Code mismatch for function {} at offset {}".format(
debuginfo.format_di_key(func_di_key), offset))
result = []
modulo = 1 << 64
format_key = lambda: key if isinstance(key, basestring
) else debuginfo.format_di_key(key)
check_sym = functools.partial(check_interposable,
get_module_symtab(new_elf).module_sym_names)
for obj in obj_seq:
obj_di = debuginfo.get_debug_info(obj)
for func_di_key, (
obj_text_sec,
relocs) in ObjectFile(obj).get_relocs(check_sym).iteritems():
func_new_dio = new_elf_di.get_dio_by_key(func_di_key)
func_obj_dio = obj_di.get_dio_by_key(func_di_key)
func_new_addr = func_new_dio.get_addr()
func_obj_addr = func_obj_dio.get_addr()
cmp_func()
for rel_type, rel_offset, key in relocs:
if rel_type not in RELOC_PIC_TYPES:
continue
if key is None:
continue
patch_address = func_new_addr + rel_offset
old_addr = get_addr(old_elf, key)
if not old_addr:
print "!! {} is absent in old ELF".format(format_key())
continue
rel_size = RELOC_SIZES[rel_type]
rel_value = read_num(new_text_sec, patch_address, rel_size)
if rel_size < 8:
rel_value = sign_extend(rel_value, 8 * rel_size, 64)
new_addr = get_addr(new_elf, key)
# Emulate arithmetic modulo 2**64
# To get final address, one should subtract base load address of new ELF, and
# add base load address of old ELF (zero for executables). This calculation
# should also be made with modulo arithmetic. Then, for small relocation size
# one should verify that truncated value sign-extends to the full value.
target_value = (rel_value + old_addr - new_addr) % modulo
result.append((rel_size, patch_address, target_value))
return result