gdb/testsuite/gdb.python/py-unwind.py - binutils-gdb - Git at Google

 # Copyright (C) 2015-2024 Free Software Foundation, Inc.

 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.

 import gdb
 from gdb.unwinder import FrameId, Unwinder

 # These are set to test whether invalid register names cause an error.
 add_saved_register_errors = {}
 read_register_error = False


 class TestUnwinder(Unwinder):
     AMD64_RBP = 6
     AMD64_RSP = 7
     AMD64_RIP = None

     def __init__(self):
         Unwinder.__init__(self, "test unwinder")
         self.char_ptr_t = gdb.lookup_type("unsigned char").pointer()
         self.char_ptr_ptr_t = self.char_ptr_t.pointer()
         self._last_arch = None

     # Update the register descriptor AMD64_RIP based on ARCH.
     def _update_register_descriptors(self, arch):
         if self._last_arch != arch:
             TestUnwinder.AMD64_RIP = arch.registers().find("rip")
             self._last_arch = arch

     def _read_word(self, address):
         return address.cast(self.char_ptr_ptr_t).dereference()

     def __call__(self, pending_frame):
         """Test unwinder written in Python.

         This unwinder can unwind the frames that have been deliberately
         corrupted in a specific way (functions in the accompanying
         py-unwind.c file do that.)
         This code is only on AMD64.
         On AMD64 $RBP points to the innermost frame (unless the code
         was compiled with -fomit-frame-pointer), which contains the
         address of the previous frame at offset 0. The functions
         deliberately corrupt their frames as follows:
                      Before                 After
                    Corruption:           Corruption:
                 +--------------+       +--------------+
         RBP-8   |              |       | Previous RBP |
                 +--------------+       +--------------+
         RBP     + Previous RBP |       |    RBP       |
                 +--------------+       +--------------+
         RBP+8   | Return RIP   |       | Return  RIP  |
                 +--------------+       +--------------+
         Old SP  |              |       |              |

         This unwinder recognizes the corrupt frames by checking that
         *RBP == RBP, and restores previous RBP from the word above it.
         """

         # Check that we can access the architecture of the pending
         # frame, and that this is the same architecture as for the
         # currently selected inferior.
         inf_arch = gdb.selected_inferior().architecture()
         frame_arch = pending_frame.architecture()
         if inf_arch != frame_arch:
             raise gdb.GdbError("architecture mismatch")

         self._update_register_descriptors(frame_arch)

         try:
             # NOTE: the registers in Unwinder API can be referenced
             # either by name or by number. The code below uses both
             # to achieve more coverage.
             bp = pending_frame.read_register("rbp").cast(self.char_ptr_t)
             if self._read_word(bp) != bp:
                 return None
             # Found the frame that the test program has corrupted for us.
             # The correct BP for the outer frame has been saved one word
             # above, previous IP and SP are at the expected places.
             previous_bp = self._read_word(bp - 8)
             previous_ip = self._read_word(bp + 8)
             previous_sp = bp + 16

             try:
                 pending_frame.read_register("nosuchregister")
             except ValueError as ve:
                 global read_register_error
                 read_register_error = str(ve)

             frame_id = FrameId(
                 pending_frame.read_register(register=TestUnwinder.AMD64_RSP),
                 pending_frame.read_register(TestUnwinder.AMD64_RIP),
             )
             unwind_info = pending_frame.create_unwind_info(frame_id)
             unwind_info.add_saved_register(TestUnwinder.AMD64_RBP, previous_bp)
             unwind_info.add_saved_register(value=previous_ip, register="rip")
             unwind_info.add_saved_register(register="rsp", value=previous_sp)

             global add_saved_register_errors
             try:
                 unwind_info.add_saved_register("nosuchregister", previous_sp)
             except ValueError as ve:
                 add_saved_register_errors["unknown_name"] = str(ve)

             try:
                 unwind_info.add_saved_register(999, previous_sp)
             except ValueError as ve:
                 add_saved_register_errors["unknown_number"] = str(ve)

             try:
                 unwind_info.add_saved_register("rsp", 1234)
             except TypeError as ve:
                 add_saved_register_errors["bad_value"] = str(ve)

             return unwind_info
         except (gdb.error, RuntimeError):
             return None


 global_test_unwinder = TestUnwinder()
 gdb.unwinder.register_unwinder(None, global_test_unwinder, True)

 # These are filled in by the simple_unwinder class.
 captured_pending_frame = None
 captured_pending_frame_repr = None
 captured_unwind_info = None
 captured_unwind_info_repr = None


 class simple_unwinder(Unwinder):
     def __init__(self, name, sp=0x123, pc=0x456):
         super().__init__(name)
         self._sp = sp
         self._pc = pc

     def __call__(self, pending_frame):
         global captured_pending_frame
         global captured_pending_frame_repr
         global captured_unwind_info
         global captured_unwind_info_repr

         assert pending_frame.is_valid()

         if captured_pending_frame is None:
             captured_pending_frame = pending_frame
             captured_pending_frame_repr = repr(pending_frame)
             fid = FrameId(self._sp, self._pc)
             uw = pending_frame.create_unwind_info(frame_id=fid)
             uw.add_saved_register("rip", gdb.Value(0x123))
             uw.add_saved_register("rbp", gdb.Value(0x456))
             uw.add_saved_register("rsp", gdb.Value(0x789))
             captured_unwind_info = uw
             captured_unwind_info_repr = repr(uw)
         return None


 # Return a dictionary of information about FRAME.
 def capture_frame_information(frame):
     name = frame.name()
     level = frame.level()
     language = frame.language()
     function = frame.function()
     architecture = frame.architecture()
     pc = frame.pc()
     sal = frame.find_sal()
     try:
         block = frame.block()
         assert isinstance(block, gdb.Block)
     except RuntimeError as rte:
         assert str(rte) == "Cannot locate block for frame."
         block = "RuntimeError: " + str(rte)

     return {
         "name": name,
         "level": level,
         "language": language,
         "function": function,
         "architecture": architecture,
         "pc": pc,
         "sal": sal,
         "block": block,
     }


 # List of information about each frame.  The index into this list is
 # the frame level.  This is populated by
 # capture_all_frame_information.
 all_frame_information = []


 # Fill in the global ALL_FRAME_INFORMATION list.
 def capture_all_frame_information():
     global all_frame_information

     all_frame_information = []

     gdb.newest_frame().select()
     frame = gdb.selected_frame()
     count = 0

     while frame is not None:
         frame.select()
         info = capture_frame_information(frame)
         level = info["level"]
         info["matched"] = False

         while len(all_frame_information) <= level:
             all_frame_information.append(None)

         assert all_frame_information[level] is None
         all_frame_information[level] = info

         if frame.name == "main" or count > 10:
             break

         count += 1
         frame = frame.older()


 # Assert that every entry in the global ALL_FRAME_INFORMATION list was
 # matched by the validating_unwinder.
 def check_all_frame_information_matched():
     global all_frame_information
     for entry in all_frame_information:
         assert entry["matched"]


 # An unwinder that doesn't match any frames.  What it does do is
 # lookup information from the PendingFrame object and compare it
 # against information stored in the global ALL_FRAME_INFORMATION list.
 class validating_unwinder(Unwinder):
     def __init__(self):
         super().__init__("validating_unwinder")

     def __call__(self, pending_frame):
         info = capture_frame_information(pending_frame)
         level = info["level"]

         global all_frame_information
         old_info = all_frame_information[level]

         assert old_info is not None
         assert not old_info["matched"]

         for key, value in info.items():
             assert key in old_info, key + " not in old_info"
             assert type(value) == type(old_info[key])
             if isinstance(value, gdb.Block):
                 assert value.start == old_info[key].start
                 assert value.end == old_info[key].end
                 assert value.is_static == old_info[key].is_static
                 assert value.is_global == old_info[key].is_global
             else:
                 assert str(value) == str(old_info[key])

         old_info["matched"] = True
         return None


 print("Python script imported")
	# Copyright (C) 2015-2024 Free Software Foundation, Inc.

	# This program is free software; you can redistribute it and/or modify
	# it under the terms of the GNU General Public License as published by
	# the Free Software Foundation; either version 3 of the License, or
	# (at your option) any later version.
	#
	# This program is distributed in the hope that it will be useful,
	# but WITHOUT ANY WARRANTY; without even the implied warranty of
	# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	# GNU General Public License for more details.
	#
	# You should have received a copy of the GNU General Public License
	# along with this program. If not, see <http://www.gnu.org/licenses/>.

	import gdb
	from gdb.unwinder import FrameId, Unwinder

	# These are set to test whether invalid register names cause an error.
	add_saved_register_errors = {}
	read_register_error = False


	class TestUnwinder(Unwinder):
	AMD64_RBP = 6
	AMD64_RSP = 7
	AMD64_RIP = None

	def __init__(self):
	Unwinder.__init__(self, "test unwinder")
	self.char_ptr_t = gdb.lookup_type("unsigned char").pointer()
	self.char_ptr_ptr_t = self.char_ptr_t.pointer()
	self._last_arch = None

	# Update the register descriptor AMD64_RIP based on ARCH.
	def _update_register_descriptors(self, arch):
	if self._last_arch != arch:
	TestUnwinder.AMD64_RIP = arch.registers().find("rip")
	self._last_arch = arch

	def _read_word(self, address):
	return address.cast(self.char_ptr_ptr_t).dereference()

	def __call__(self, pending_frame):
	"""Test unwinder written in Python.

	This unwinder can unwind the frames that have been deliberately
	corrupted in a specific way (functions in the accompanying
	py-unwind.c file do that.)
	This code is only on AMD64.
	On AMD64 $RBP points to the innermost frame (unless the code
	was compiled with -fomit-frame-pointer), which contains the
	address of the previous frame at offset 0. The functions
	deliberately corrupt their frames as follows:
	Before After
	Corruption: Corruption:
	+--------------+ +--------------+
	RBP-8 \| \| \| Previous RBP \|
	+--------------+ +--------------+
	RBP + Previous RBP \| \| RBP \|
	+--------------+ +--------------+
	RBP+8 \| Return RIP \| \| Return RIP \|
	+--------------+ +--------------+
	Old SP \| \| \| \|

	This unwinder recognizes the corrupt frames by checking that
	*RBP == RBP, and restores previous RBP from the word above it.
	"""

	# Check that we can access the architecture of the pending
	# frame, and that this is the same architecture as for the
	# currently selected inferior.
	inf_arch = gdb.selected_inferior().architecture()
	frame_arch = pending_frame.architecture()
	if inf_arch != frame_arch:
	raise gdb.GdbError("architecture mismatch")

	self._update_register_descriptors(frame_arch)

	try:
	# NOTE: the registers in Unwinder API can be referenced
	# either by name or by number. The code below uses both
	# to achieve more coverage.
	bp = pending_frame.read_register("rbp").cast(self.char_ptr_t)
	if self._read_word(bp) != bp:
	return None
	# Found the frame that the test program has corrupted for us.
	# The correct BP for the outer frame has been saved one word
	# above, previous IP and SP are at the expected places.
	previous_bp = self._read_word(bp - 8)
	previous_ip = self._read_word(bp + 8)
	previous_sp = bp + 16

	try:
	pending_frame.read_register("nosuchregister")
	except ValueError as ve:
	global read_register_error
	read_register_error = str(ve)

	frame_id = FrameId(
	pending_frame.read_register(register=TestUnwinder.AMD64_RSP),
	pending_frame.read_register(TestUnwinder.AMD64_RIP),
	)
	unwind_info = pending_frame.create_unwind_info(frame_id)
	unwind_info.add_saved_register(TestUnwinder.AMD64_RBP, previous_bp)
	unwind_info.add_saved_register(value=previous_ip, register="rip")
	unwind_info.add_saved_register(register="rsp", value=previous_sp)

	global add_saved_register_errors
	try:
	unwind_info.add_saved_register("nosuchregister", previous_sp)
	except ValueError as ve:
	add_saved_register_errors["unknown_name"] = str(ve)

	try:
	unwind_info.add_saved_register(999, previous_sp)
	except ValueError as ve:
	add_saved_register_errors["unknown_number"] = str(ve)

	try:
	unwind_info.add_saved_register("rsp", 1234)
	except TypeError as ve:
	add_saved_register_errors["bad_value"] = str(ve)

	return unwind_info
	except (gdb.error, RuntimeError):
	return None


	global_test_unwinder = TestUnwinder()
	gdb.unwinder.register_unwinder(None, global_test_unwinder, True)

	# These are filled in by the simple_unwinder class.
	captured_pending_frame = None
	captured_pending_frame_repr = None
	captured_unwind_info = None
	captured_unwind_info_repr = None


	class simple_unwinder(Unwinder):
	def __init__(self, name, sp=0x123, pc=0x456):
	super().__init__(name)
	self._sp = sp
	self._pc = pc

	def __call__(self, pending_frame):
	global captured_pending_frame
	global captured_pending_frame_repr
	global captured_unwind_info
	global captured_unwind_info_repr

	assert pending_frame.is_valid()

	if captured_pending_frame is None:
	captured_pending_frame = pending_frame
	captured_pending_frame_repr = repr(pending_frame)
	fid = FrameId(self._sp, self._pc)
	uw = pending_frame.create_unwind_info(frame_id=fid)
	uw.add_saved_register("rip", gdb.Value(0x123))
	uw.add_saved_register("rbp", gdb.Value(0x456))
	uw.add_saved_register("rsp", gdb.Value(0x789))
	captured_unwind_info = uw
	captured_unwind_info_repr = repr(uw)
	return None


	# Return a dictionary of information about FRAME.
	def capture_frame_information(frame):
	name = frame.name()
	level = frame.level()
	language = frame.language()
	function = frame.function()
	architecture = frame.architecture()
	pc = frame.pc()
	sal = frame.find_sal()
	try:
	block = frame.block()
	assert isinstance(block, gdb.Block)
	except RuntimeError as rte:
	assert str(rte) == "Cannot locate block for frame."
	block = "RuntimeError: " + str(rte)

	return {
	"name": name,
	"level": level,
	"language": language,
	"function": function,
	"architecture": architecture,
	"pc": pc,
	"sal": sal,
	"block": block,
	}


	# List of information about each frame. The index into this list is
	# the frame level. This is populated by
	# capture_all_frame_information.
	all_frame_information = []


	# Fill in the global ALL_FRAME_INFORMATION list.
	def capture_all_frame_information():
	global all_frame_information

	all_frame_information = []

	gdb.newest_frame().select()
	frame = gdb.selected_frame()
	count = 0

	while frame is not None:
	frame.select()
	info = capture_frame_information(frame)
	level = info["level"]
	info["matched"] = False

	while len(all_frame_information) <= level:
	all_frame_information.append(None)

	assert all_frame_information[level] is None
	all_frame_information[level] = info

	if frame.name == "main" or count > 10:
	break

	count += 1
	frame = frame.older()


	# Assert that every entry in the global ALL_FRAME_INFORMATION list was
	# matched by the validating_unwinder.
	def check_all_frame_information_matched():
	global all_frame_information
	for entry in all_frame_information:
	assert entry["matched"]


	# An unwinder that doesn't match any frames. What it does do is
	# lookup information from the PendingFrame object and compare it
	# against information stored in the global ALL_FRAME_INFORMATION list.
	class validating_unwinder(Unwinder):
	def __init__(self):
	super().__init__("validating_unwinder")

	def __call__(self, pending_frame):
	info = capture_frame_information(pending_frame)
	level = info["level"]

	global all_frame_information
	old_info = all_frame_information[level]

	assert old_info is not None
	assert not old_info["matched"]

	for key, value in info.items():
	assert key in old_info, key + " not in old_info"
	assert type(value) == type(old_info[key])
	if isinstance(value, gdb.Block):
	assert value.start == old_info[key].start
	assert value.end == old_info[key].end
	assert value.is_static == old_info[key].is_static
	assert value.is_global == old_info[key].is_global
	else:
	assert str(value) == str(old_info[key])

	old_info["matched"] = True
	return None


	print("Python script imported")