def is_pyobject_ptr(addr):
try:
_type_pyop = caching_lookup_type('PyObject').pointer()
_type_pyvarop = caching_lookup_type('PyVarObject').pointer()
except RuntimeError:
# not linked against python
return None
pyop = gdb.Value(addr).cast(_type_pyop)
try:
ob_refcnt = pyop['ob_refcnt']
if ob_refcnt >=0 and ob_refcnt < 0xffff:
obtype = pyop['ob_type']
if obtype != 0:
type_refcnt = obtype.cast(_type_pyop)['ob_refcnt']
if type_refcnt > 0 and type_refcnt < 0xffff:
type_ob_size = obtype.cast(_type_pyvarop)['ob_size']
if type_ob_size > 0xffff:
return 0
for fieldname in ('tp_del', 'tp_mro', 'tp_init', 'tp_getset'):
if not looks_like_ptr(obtype[fieldname]):
return 0
# Then this looks like a Python object:
return PyObjectPtr.from_pyobject_ptr(pyop)
except (RuntimeError, UnicodeDecodeError):
pass # Not a python object (or corrupt)
def is_pyobject_ptr(addr):
try:
_type_pyop = caching_lookup_type('PyObject').pointer()
_type_pyvarop = caching_lookup_type('PyVarObject').pointer()
except RuntimeError:
# not linked against python
return None
pyop = gdb.Value(addr).cast(_type_pyop)
try:
ob_refcnt = pyop['ob_refcnt']
if ob_refcnt >=0 and ob_refcnt < 0xffff:
obtype = pyop['ob_type']
if obtype != 0:
type_refcnt = obtype.cast(_type_pyop)['ob_refcnt']
if type_refcnt > 0 and type_refcnt < 0xffff:
type_ob_size = obtype.cast(_type_pyvarop)['ob_size']
if type_ob_size > 0xffff:
return 0
for fieldname in ('tp_del', 'tp_mro', 'tp_init', 'tp_getset'):
if not looks_like_ptr(obtype[fieldname]):
return 0
# Then this looks like a Python object:
return PyObjectPtr.from_pyobject_ptr(pyop)
except (RuntimeError, UnicodeDecodeError):
pass # Not a python object (or corrupt)
def get_class_name(addr, size):
# Try to detect a vtable ptr at the top of this object:
vtable = gdb.Value(addr).cast(void_ptr_ptr).dereference()
if not looks_like_ptr(vtable):
return None
info = execute('info sym (void *)0x%x' % long(vtable))
# "vtable for Foo + 8 in section .rodata of /home/david/heap/test_cplusplus"
m = re.match('vtable for (.*) \+ (.*)', info)
if m:
return m.group(1)
# Not matched:
return None
def get_class_name(addr, size):
# Try to detect a vtable ptr at the top of this object:
vtable = gdb.Value(addr).cast(void_ptr_ptr).dereference()
if not looks_like_ptr(vtable):
return None
info = execute('info sym (void *)0x%x' % long(vtable))
# "vtable for Foo + 8 in section .rodata of /home/david/heap/test_cplusplus"
m = re.match('vtable for (.*) \+ (.*)', info)
if m:
return m.group(1)
# Not matched:
return None
def is_pyobject_ptr(addr):
try:
_type_pyop = caching_lookup_type('PyObject').pointer()
_type_pyvarop = caching_lookup_type('PyVarObject').pointer()
except RuntimeError:
# not linked against python
return None
try:
typeop = pyop = gdb.Value(addr).cast(_type_pyop)
# If we follow type chain on a PyObject long enough, we should arrive
# at 'type' and type(type) should be 'type'.
# The levels are: a <- b means a = type(b)
# 0 - type
# 1 - type <- class A
# type <- class M(type)
# 2 - type <- class A <- A()
# type <- class M(type) <- class B(metaclass=M)
# 3 - type <- class M(type) <- class B(metaclass=M) <- B()
for i in range(4):
if typeop['ob_type'] == typeop:
return PyObjectPtr.from_pyobject_ptr(pyop)
typeop = typeop['ob_type'].cast(_type_pyop)
return 0
# gdb.write('PYOP {}\n'.format(pyop))
ob_refcnt = pyop['ob_refcnt']
if ob_refcnt >= 0 and ob_refcnt < 0xffff:
# gdb.write('refcnt ok {}\n'.format(int(ob_refcnt)))
obtype = pyop['ob_type']
if looks_like_ptr(obtype):
# gdb.write('obtype ok {}\n'.format(obtype))
type_refcnt = obtype.cast(_type_pyop)['ob_refcnt']
if type_refcnt > 0 and type_refcnt < 0xffff:
# gdb.write('type refcnt ok\n')
# type_ob_size = obtype.cast(_type_pyvarop)['ob_size']
# if type_ob_size > 0xffff:
# return 0
# gdb.write('ob size ok\n')
for fieldname in ('tp_base', 'tp_free', 'tp_repr',
'tp_new'):
if not looks_like_ptr(obtype[fieldname]):
return 0
# gdb.write('methods ok\n')
# Then this looks like a Python object:
return PyObjectPtr.from_pyobject_ptr(pyop)
except UnicodeDecodeError as e:
# print('is_pyobject_ptr 0x{:x}'.format(addr))
# gdb.write(str(e) + '\n')
pass
except RuntimeError:
pass # Not a python object (or corrupt)
