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cpython/Lib/test/test_gdb.py

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# Verify that gdb can pretty-print the various PyObject* types
#
# The code for testing gdb was adapted from similar work in Unladen Swallow's
# Lib/test/test_jit_gdb.py
import os
import platform
import re
import subprocess
import sys
import sysconfig
import textwrap
import unittest
from test import support
from test.support import findfile, python_is_optimized
def get_gdb_version():
try:
proc = subprocess.Popen(["gdb", "-nx", "--version"],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
universal_newlines=True)
with proc:
version = proc.communicate()[0]
except OSError:
# This is what "no gdb" looks like. There may, however, be other
# errors that manifest this way too.
raise unittest.SkipTest("Couldn't find gdb on the path")
# Regex to parse:
# 'GNU gdb (GDB; SUSE Linux Enterprise 12) 7.7\n' -> 7.7
# 'GNU gdb (GDB) Fedora 7.9.1-17.fc22\n' -> 7.9
# 'GNU gdb 6.1.1 [FreeBSD]\n' -> 6.1
# 'GNU gdb (GDB) Fedora (7.5.1-37.fc18)\n' -> 7.5
match = re.search(r"^GNU gdb.*?\b(\d+)\.(\d+)", version)
if match is None:
raise Exception("unable to parse GDB version: %r" % version)
return (version, int(match.group(1)), int(match.group(2)))
gdb_version, gdb_major_version, gdb_minor_version = get_gdb_version()
if gdb_major_version < 7:
raise unittest.SkipTest("gdb versions before 7.0 didn't support python "
"embedding. Saw %s.%s:\n%s"
% (gdb_major_version, gdb_minor_version,
gdb_version))
if not sysconfig.is_python_build():
raise unittest.SkipTest("test_gdb only works on source builds at the moment.")
if 'Clang' in platform.python_compiler() and sys.platform == 'darwin':
raise unittest.SkipTest("test_gdb doesn't work correctly when python is"
" built with LLVM clang")
if ((sysconfig.get_config_var('PGO_PROF_USE_FLAG') or 'xxx') in
(sysconfig.get_config_var('PY_CORE_CFLAGS') or '')):
raise unittest.SkipTest("test_gdb is not reliable on PGO builds")
# Location of custom hooks file in a repository checkout.
checkout_hook_path = os.path.join(os.path.dirname(sys.executable),
'python-gdb.py')
PYTHONHASHSEED = '123'
def cet_protection():
cflags = sysconfig.get_config_var('CFLAGS')
if not cflags:
return False
flags = cflags.split()
# True if "-mcet -fcf-protection" options are found, but false
# if "-fcf-protection=none" or "-fcf-protection=return" is found.
return (('-mcet' in flags)
and any((flag.startswith('-fcf-protection')
and not flag.endswith(("=none", "=return")))
for flag in flags))
# Control-flow enforcement technology
CET_PROTECTION = cet_protection()
def run_gdb(*args, **env_vars):
"""Runs gdb in --batch mode with the additional arguments given by *args.
Returns its (stdout, stderr) decoded from utf-8 using the replace handler.
"""
if env_vars:
env = os.environ.copy()
env.update(env_vars)
else:
env = None
# -nx: Do not execute commands from any .gdbinit initialization files
# (issue #22188)
base_cmd = ('gdb', '--batch', '-nx')
if (gdb_major_version, gdb_minor_version) >= (7, 4):
base_cmd += ('-iex', 'add-auto-load-safe-path ' + checkout_hook_path)
proc = subprocess.Popen(base_cmd + args,
# Redirect stdin to prevent GDB from messing with
# the terminal settings
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
env=env)
with proc:
out, err = proc.communicate()
return out.decode('utf-8', 'replace'), err.decode('utf-8', 'replace')
# Verify that "gdb" was built with the embedded python support enabled:
gdbpy_version, _ = run_gdb("--eval-command=python import sys; print(sys.version_info)")
if not gdbpy_version:
raise unittest.SkipTest("gdb not built with embedded python support")
# Verify that "gdb" can load our custom hooks, as OS security settings may
# disallow this without a customized .gdbinit.
_, gdbpy_errors = run_gdb('--args', sys.executable)
if "auto-loading has been declined" in gdbpy_errors:
msg = "gdb security settings prevent use of custom hooks: "
raise unittest.SkipTest(msg + gdbpy_errors.rstrip())
def gdb_has_frame_select():
# Does this build of gdb have gdb.Frame.select ?
stdout, _ = run_gdb("--eval-command=python print(dir(gdb.Frame))")
m = re.match(r'.*\[(.*)\].*', stdout)
if not m:
raise unittest.SkipTest("Unable to parse output from gdb.Frame.select test")
gdb_frame_dir = m.group(1).split(', ')
return "'select'" in gdb_frame_dir
HAS_PYUP_PYDOWN = gdb_has_frame_select()
BREAKPOINT_FN='builtin_id'
@unittest.skipIf(support.PGO, "not useful for PGO")
class DebuggerTests(unittest.TestCase):
"""Test that the debugger can debug Python."""
def get_stack_trace(self, source=None, script=None,
breakpoint=BREAKPOINT_FN,
cmds_after_breakpoint=None,
import_site=False):
'''
Run 'python -c SOURCE' under gdb with a breakpoint.
Support injecting commands after the breakpoint is reached
Returns the stdout from gdb
cmds_after_breakpoint: if provided, a list of strings: gdb commands
'''
# We use "set breakpoint pending yes" to avoid blocking with a:
# Function "foo" not defined.
# Make breakpoint pending on future shared library load? (y or [n])
# error, which typically happens python is dynamically linked (the
# breakpoints of interest are to be found in the shared library)
# When this happens, we still get:
# Function "textiowrapper_write" not defined.
# emitted to stderr each time, alas.
# Initially I had "--eval-command=continue" here, but removed it to
# avoid repeated print breakpoints when traversing hierarchical data
# structures
# Generate a list of commands in gdb's language:
commands = ['set breakpoint pending yes',
'break %s' % breakpoint,
# The tests assume that the first frame of printed
# backtrace will not contain program counter,
# that is however not guaranteed by gdb
# therefore we need to use 'set print address off' to
# make sure the counter is not there. For example:
# #0 in PyObject_Print ...
# is assumed, but sometimes this can be e.g.
# #0 0x00003fffb7dd1798 in PyObject_Print ...
'set print address off',
'run']
# GDB as of 7.4 onwards can distinguish between the
# value of a variable at entry vs current value:
# http://sourceware.org/gdb/onlinedocs/gdb/Variables.html
# which leads to the selftests failing with errors like this:
# AssertionError: 'v@entry=()' != '()'
# Disable this:
if (gdb_major_version, gdb_minor_version) >= (7, 4):
commands += ['set print entry-values no']
if cmds_after_breakpoint:
if CET_PROTECTION:
# bpo-32962: When Python is compiled with -mcet
# -fcf-protection, function arguments are unusable before
# running the first instruction of the function entry point.
# The 'next' command makes the required first step.
commands += ['next']
commands += cmds_after_breakpoint
else:
commands += ['backtrace']
# print commands
# Use "commands" to generate the arguments with which to invoke "gdb":
args = ['--eval-command=%s' % cmd for cmd in commands]
args += ["--args",
sys.executable]
args.extend(subprocess._args_from_interpreter_flags())
if not import_site:
# -S suppresses the default 'import site'
args += ["-S"]
if source:
args += ["-c", source]
elif script:
args += [script]
# Use "args" to invoke gdb, capturing stdout, stderr:
out, err = run_gdb(*args, PYTHONHASHSEED=PYTHONHASHSEED)
for line in err.splitlines():
print(line, file=sys.stderr)
# bpo-34007: Sometimes some versions of the shared libraries that
# are part of the traceback are compiled in optimised mode and the
# Program Counter (PC) is not present, not allowing gdb to walk the
# frames back. When this happens, the Python bindings of gdb raise
# an exception, making the test impossible to succeed.
if "PC not saved" in err:
raise unittest.SkipTest("gdb cannot walk the frame object"
" because the Program Counter is"
" not present")
# bpo-40019: Skip the test if gdb failed to read debug information
# because the Python binary is optimized.
for pattern in (
'(frame information optimized out)',
'Unable to read information on python frame',
):
if pattern in out:
raise unittest.SkipTest(f"{pattern!r} found in gdb output")
return out
def get_gdb_repr(self, source,
cmds_after_breakpoint=None,
import_site=False):
# Given an input python source representation of data,
# run "python -c'id(DATA)'" under gdb with a breakpoint on
# builtin_id and scrape out gdb's representation of the "op"
# parameter, and verify that the gdb displays the same string
#
# Verify that the gdb displays the expected string
#
# For a nested structure, the first time we hit the breakpoint will
# give us the top-level structure
# NOTE: avoid decoding too much of the traceback as some
# undecodable characters may lurk there in optimized mode
# (issue #19743).
cmds_after_breakpoint = cmds_after_breakpoint or ["backtrace 1"]
gdb_output = self.get_stack_trace(source, breakpoint=BREAKPOINT_FN,
cmds_after_breakpoint=cmds_after_breakpoint,
import_site=import_site)
# gdb can insert additional '\n' and space characters in various places
# in its output, depending on the width of the terminal it's connected
# to (using its "wrap_here" function)
m = re.search(
# Match '#0 builtin_id(self=..., v=...)'
r'#0\s+builtin_id\s+\(self\=.*,\s+v=\s*(.*?)?\)'
# Match ' at Python/bltinmodule.c'.
# bpo-38239: builtin_id() is defined in Python/bltinmodule.c,
# but accept any "Directory\file.c" to support Link Time
# Optimization (LTO).
r'\s+at\s+\S*[A-Za-z]+/[A-Za-z0-9_-]+\.c',
gdb_output, re.DOTALL)
if not m:
self.fail('Unexpected gdb output: %r\n%s' % (gdb_output, gdb_output))
return m.group(1), gdb_output
def assertEndsWith(self, actual, exp_end):
'''Ensure that the given "actual" string ends with "exp_end"'''
self.assertTrue(actual.endswith(exp_end),
msg='%r did not end with %r' % (actual, exp_end))
def assertMultilineMatches(self, actual, pattern):
m = re.match(pattern, actual, re.DOTALL)
if not m:
self.fail(msg='%r did not match %r' % (actual, pattern))
def get_sample_script(self):
return findfile('gdb_sample.py')
class PrettyPrintTests(DebuggerTests):
def test_getting_backtrace(self):
gdb_output = self.get_stack_trace('id(42)')
self.assertTrue(BREAKPOINT_FN in gdb_output)
def assertGdbRepr(self, val, exp_repr=None):
# Ensure that gdb's rendering of the value in a debugged process
# matches repr(value) in this process:
gdb_repr, gdb_output = self.get_gdb_repr('id(' + ascii(val) + ')')
if not exp_repr:
exp_repr = repr(val)
self.assertEqual(gdb_repr, exp_repr,
('%r did not equal expected %r; full output was:\n%s'
% (gdb_repr, exp_repr, gdb_output)))
def test_int(self):
'Verify the pretty-printing of various int values'
self.assertGdbRepr(42)
self.assertGdbRepr(0)
self.assertGdbRepr(-7)
self.assertGdbRepr(1000000000000)
self.assertGdbRepr(-1000000000000000)
def test_singletons(self):
'Verify the pretty-printing of True, False and None'
self.assertGdbRepr(True)
self.assertGdbRepr(False)
self.assertGdbRepr(None)
def test_dicts(self):
'Verify the pretty-printing of dictionaries'
self.assertGdbRepr({})
self.assertGdbRepr({'foo': 'bar'}, "{'foo': 'bar'}")
# Python preserves insertion order since 3.6
self.assertGdbRepr({'foo': 'bar', 'douglas': 42}, "{'foo': 'bar', 'douglas': 42}")
def test_lists(self):
'Verify the pretty-printing of lists'
self.assertGdbRepr([])
self.assertGdbRepr(list(range(5)))
def test_bytes(self):
'Verify the pretty-printing of bytes'
self.assertGdbRepr(b'')
self.assertGdbRepr(b'And now for something hopefully the same')
self.assertGdbRepr(b'string with embedded NUL here \0 and then some more text')
self.assertGdbRepr(b'this is a tab:\t'
b' this is a slash-N:\n'
b' this is a slash-R:\r'
)
self.assertGdbRepr(b'this is byte 255:\xff and byte 128:\x80')
self.assertGdbRepr(bytes([b for b in range(255)]))
def test_strings(self):
'Verify the pretty-printing of unicode strings'
# We cannot simply call locale.getpreferredencoding() here,
# as GDB might have been linked against a different version
# of Python with a different encoding and coercion policy
# with respect to PEP 538 and PEP 540.
out, err = run_gdb(
'--eval-command',
'python import locale; print(locale.getpreferredencoding())')
encoding = out.rstrip()
if err or not encoding:
raise RuntimeError(
f'unable to determine the preferred encoding '
f'of embedded Python in GDB: {err}')
def check_repr(text):
try:
text.encode(encoding)
except UnicodeEncodeError:
self.assertGdbRepr(text, ascii(text))
else:
self.assertGdbRepr(text)
self.assertGdbRepr('')
self.assertGdbRepr('And now for something hopefully the same')
self.assertGdbRepr('string with embedded NUL here \0 and then some more text')
# Test printing a single character:
# U+2620 SKULL AND CROSSBONES
check_repr('\u2620')
# Test printing a Japanese unicode string
# (I believe this reads "mojibake", using 3 characters from the CJK
# Unified Ideographs area, followed by U+3051 HIRAGANA LETTER KE)
check_repr('\u6587\u5b57\u5316\u3051')
# Test a character outside the BMP:
# U+1D121 MUSICAL SYMBOL C CLEF
# This is:
# UTF-8: 0xF0 0x9D 0x84 0xA1
# UTF-16: 0xD834 0xDD21
check_repr(chr(0x1D121))
def test_tuples(self):
'Verify the pretty-printing of tuples'
self.assertGdbRepr(tuple(), '()')
self.assertGdbRepr((1,), '(1,)')
self.assertGdbRepr(('foo', 'bar', 'baz'))
def test_sets(self):
'Verify the pretty-printing of sets'
if (gdb_major_version, gdb_minor_version) < (7, 3):
self.skipTest("pretty-printing of sets needs gdb 7.3 or later")
self.assertGdbRepr(set(), "set()")
self.assertGdbRepr(set(['a']), "{'a'}")
# PYTHONHASHSEED is need to get the exact frozenset item order
if not sys.flags.ignore_environment:
self.assertGdbRepr(set(['a', 'b']), "{'a', 'b'}")
self.assertGdbRepr(set([4, 5, 6]), "{4, 5, 6}")
# Ensure that we handle sets containing the "dummy" key value,
# which happens on deletion:
gdb_repr, gdb_output = self.get_gdb_repr('''s = set(['a','b'])
s.remove('a')
id(s)''')
self.assertEqual(gdb_repr, "{'b'}")
def test_frozensets(self):
'Verify the pretty-printing of frozensets'
if (gdb_major_version, gdb_minor_version) < (7, 3):
self.skipTest("pretty-printing of frozensets needs gdb 7.3 or later")
self.assertGdbRepr(frozenset(), "frozenset()")
self.assertGdbRepr(frozenset(['a']), "frozenset({'a'})")
# PYTHONHASHSEED is need to get the exact frozenset item order
if not sys.flags.ignore_environment:
self.assertGdbRepr(frozenset(['a', 'b']), "frozenset({'a', 'b'})")
self.assertGdbRepr(frozenset([4, 5, 6]), "frozenset({4, 5, 6})")
def test_exceptions(self):
# Test a RuntimeError
gdb_repr, gdb_output = self.get_gdb_repr('''
try:
raise RuntimeError("I am an error")
except RuntimeError as e:
id(e)
''')
self.assertEqual(gdb_repr,
"RuntimeError('I am an error',)")
# Test division by zero:
gdb_repr, gdb_output = self.get_gdb_repr('''
try:
a = 1 / 0
except ZeroDivisionError as e:
id(e)
''')
self.assertEqual(gdb_repr,
"ZeroDivisionError('division by zero',)")
def test_modern_class(self):
'Verify the pretty-printing of new-style class instances'
gdb_repr, gdb_output = self.get_gdb_repr('''
class Foo:
pass
foo = Foo()
foo.an_int = 42
id(foo)''')
m = re.match(r'<Foo\(an_int=42\) at remote 0x-?[0-9a-f]+>', gdb_repr)
self.assertTrue(m,
msg='Unexpected new-style class rendering %r' % gdb_repr)
def test_subclassing_list(self):
'Verify the pretty-printing of an instance of a list subclass'
gdb_repr, gdb_output = self.get_gdb_repr('''
class Foo(list):
pass
foo = Foo()
foo += [1, 2, 3]
foo.an_int = 42
id(foo)''')
m = re.match(r'<Foo\(an_int=42\) at remote 0x-?[0-9a-f]+>', gdb_repr)
self.assertTrue(m,
msg='Unexpected new-style class rendering %r' % gdb_repr)
def test_subclassing_tuple(self):
'Verify the pretty-printing of an instance of a tuple subclass'
# This should exercise the negative tp_dictoffset code in the
# new-style class support
gdb_repr, gdb_output = self.get_gdb_repr('''
class Foo(tuple):
pass
foo = Foo((1, 2, 3))
foo.an_int = 42
id(foo)''')
m = re.match(r'<Foo\(an_int=42\) at remote 0x-?[0-9a-f]+>', gdb_repr)
self.assertTrue(m,
msg='Unexpected new-style class rendering %r' % gdb_repr)
def assertSane(self, source, corruption, exprepr=None):
'''Run Python under gdb, corrupting variables in the inferior process
immediately before taking a backtrace.
Verify that the variable's representation is the expected failsafe
representation'''
if corruption:
cmds_after_breakpoint=[corruption, 'backtrace']
else:
cmds_after_breakpoint=['backtrace']
gdb_repr, gdb_output = \
self.get_gdb_repr(source,
cmds_after_breakpoint=cmds_after_breakpoint)
if exprepr:
if gdb_repr == exprepr:
# gdb managed to print the value in spite of the corruption;
# this is good (see http://bugs.python.org/issue8330)
return
# Match anything for the type name; 0xDEADBEEF could point to
# something arbitrary (see http://bugs.python.org/issue8330)
pattern = '<.* at remote 0x-?[0-9a-f]+>'
m = re.match(pattern, gdb_repr)
if not m:
self.fail('Unexpected gdb representation: %r\n%s' % \
(gdb_repr, gdb_output))
def test_NULL_ptr(self):
'Ensure that a NULL PyObject* is handled gracefully'
gdb_repr, gdb_output = (
self.get_gdb_repr('id(42)',
cmds_after_breakpoint=['set variable v=0',
'backtrace'])
)
self.assertEqual(gdb_repr, '0x0')
def test_NULL_ob_type(self):
'Ensure that a PyObject* with NULL ob_type is handled gracefully'
self.assertSane('id(42)',
'set v->ob_type=0')
def test_corrupt_ob_type(self):
'Ensure that a PyObject* with a corrupt ob_type is handled gracefully'
self.assertSane('id(42)',
'set v->ob_type=0xDEADBEEF',
exprepr='42')
def test_corrupt_tp_flags(self):
'Ensure that a PyObject* with a type with corrupt tp_flags is handled'
self.assertSane('id(42)',
'set v->ob_type->tp_flags=0x0',
exprepr='42')
def test_corrupt_tp_name(self):
'Ensure that a PyObject* with a type with corrupt tp_name is handled'
self.assertSane('id(42)',
'set v->ob_type->tp_name=0xDEADBEEF',
exprepr='42')
def test_builtins_help(self):
'Ensure that the new-style class _Helper in site.py can be handled'
if sys.flags.no_site:
self.skipTest("need site module, but -S option was used")
# (this was the issue causing tracebacks in
# http://bugs.python.org/issue8032#msg100537 )
gdb_repr, gdb_output = self.get_gdb_repr('id(__builtins__.help)', import_site=True)
m = re.match(r'<_Helper at remote 0x-?[0-9a-f]+>', gdb_repr)
self.assertTrue(m,
msg='Unexpected rendering %r' % gdb_repr)
def test_selfreferential_list(self):
'''Ensure that a reference loop involving a list doesn't lead proxyval
into an infinite loop:'''
gdb_repr, gdb_output = \
self.get_gdb_repr("a = [3, 4, 5] ; a.append(a) ; id(a)")
self.assertEqual(gdb_repr, '[3, 4, 5, [...]]')
gdb_repr, gdb_output = \
self.get_gdb_repr("a = [3, 4, 5] ; b = [a] ; a.append(b) ; id(a)")
self.assertEqual(gdb_repr, '[3, 4, 5, [[...]]]')
def test_selfreferential_dict(self):
'''Ensure that a reference loop involving a dict doesn't lead proxyval
into an infinite loop:'''
gdb_repr, gdb_output = \
self.get_gdb_repr("a = {} ; b = {'bar':a} ; a['foo'] = b ; id(a)")
self.assertEqual(gdb_repr, "{'foo': {'bar': {...}}}")
def test_selfreferential_old_style_instance(self):
gdb_repr, gdb_output = \
self.get_gdb_repr('''
class Foo:
pass
foo = Foo()
foo.an_attr = foo
id(foo)''')
self.assertTrue(re.match(r'<Foo\(an_attr=<\.\.\.>\) at remote 0x-?[0-9a-f]+>',
gdb_repr),
'Unexpected gdb representation: %r\n%s' % \
(gdb_repr, gdb_output))
def test_selfreferential_new_style_instance(self):
gdb_repr, gdb_output = \
self.get_gdb_repr('''
class Foo(object):
pass
foo = Foo()
foo.an_attr = foo
id(foo)''')
self.assertTrue(re.match(r'<Foo\(an_attr=<\.\.\.>\) at remote 0x-?[0-9a-f]+>',
gdb_repr),
'Unexpected gdb representation: %r\n%s' % \
(gdb_repr, gdb_output))
gdb_repr, gdb_output = \
self.get_gdb_repr('''
class Foo(object):
pass
a = Foo()
b = Foo()
a.an_attr = b
b.an_attr = a
id(a)''')
self.assertTrue(re.match(r'<Foo\(an_attr=<Foo\(an_attr=<\.\.\.>\) at remote 0x-?[0-9a-f]+>\) at remote 0x-?[0-9a-f]+>',
gdb_repr),
'Unexpected gdb representation: %r\n%s' % \
(gdb_repr, gdb_output))
def test_truncation(self):
'Verify that very long output is truncated'
gdb_repr, gdb_output = self.get_gdb_repr('id(list(range(1000)))')
self.assertEqual(gdb_repr,
"[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, "
"14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, "
"27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, "
"40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, "
"53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, "
"66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, "
"79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, "
"92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, "
"104, 105, 106, 107, 108, 109, 110, 111, 112, 113, "
"114, 115, 116, 117, 118, 119, 120, 121, 122, 123, "
"124, 125, 126, 127, 128, 129, 130, 131, 132, 133, "
"134, 135, 136, 137, 138, 139, 140, 141, 142, 143, "
"144, 145, 146, 147, 148, 149, 150, 151, 152, 153, "
"154, 155, 156, 157, 158, 159, 160, 161, 162, 163, "
"164, 165, 166, 167, 168, 169, 170, 171, 172, 173, "
"174, 175, 176, 177, 178, 179, 180, 181, 182, 183, "
"184, 185, 186, 187, 188, 189, 190, 191, 192, 193, "
"194, 195, 196, 197, 198, 199, 200, 201, 202, 203, "
"204, 205, 206, 207, 208, 209, 210, 211, 212, 213, "
"214, 215, 216, 217, 218, 219, 220, 221, 222, 223, "
"224, 225, 226...(truncated)")
self.assertEqual(len(gdb_repr),
1024 + len('...(truncated)'))
def test_builtin_method(self):
gdb_repr, gdb_output = self.get_gdb_repr('import sys; id(sys.stdout.readlines)')
self.assertTrue(re.match(r'<built-in method readlines of _io.TextIOWrapper object at remote 0x-?[0-9a-f]+>',
gdb_repr),
'Unexpected gdb representation: %r\n%s' % \
(gdb_repr, gdb_output))
def test_frames(self):
gdb_output = self.get_stack_trace('''
def foo(a, b, c):
pass
foo(3, 4, 5)
id(foo.__code__)''',
breakpoint='builtin_id',
cmds_after_breakpoint=['print (PyFrameObject*)(((PyCodeObject*)v)->co_zombieframe)']
)
self.assertTrue(re.match(r'.*\s+\$1 =\s+Frame 0x-?[0-9a-f]+, for file <string>, line 3, in foo \(\)\s+.*',
gdb_output,
re.DOTALL),
'Unexpected gdb representation: %r\n%s' % (gdb_output, gdb_output))
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
class PyListTests(DebuggerTests):
def assertListing(self, expected, actual):
self.assertEndsWith(actual, expected)
def test_basic_command(self):
'Verify that the "py-list" command works'
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-list'])
self.assertListing(' 5 \n'
' 6 def bar(a, b, c):\n'
' 7 baz(a, b, c)\n'
' 8 \n'
' 9 def baz(*args):\n'
' >10 id(42)\n'
' 11 \n'
' 12 foo(1, 2, 3)\n',
bt)
def test_one_abs_arg(self):
'Verify the "py-list" command with one absolute argument'
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-list 9'])
self.assertListing(' 9 def baz(*args):\n'
' >10 id(42)\n'
' 11 \n'
' 12 foo(1, 2, 3)\n',
bt)
def test_two_abs_args(self):
'Verify the "py-list" command with two absolute arguments'
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-list 1,3'])
self.assertListing(' 1 # Sample script for use by test_gdb.py\n'
' 2 \n'
' 3 def foo(a, b, c):\n',
bt)
class StackNavigationTests(DebuggerTests):
@unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands")
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
def test_pyup_command(self):
'Verify that the "py-up" command works'
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-up', 'py-up'])
self.assertMultilineMatches(bt,
r'''^.*
#[0-9]+ Frame 0x-?[0-9a-f]+, for file .*gdb_sample.py, line 7, in bar \(a=1, b=2, c=3\)
baz\(a, b, c\)
$''')
@unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands")
def test_down_at_bottom(self):
'Verify handling of "py-down" at the bottom of the stack'
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-down'])
self.assertEndsWith(bt,
'Unable to find a newer python frame\n')
@unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands")
def test_up_at_top(self):
'Verify handling of "py-up" at the top of the stack'
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-up'] * 5)
self.assertEndsWith(bt,
'Unable to find an older python frame\n')
@unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands")
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
def test_up_then_down(self):
'Verify "py-up" followed by "py-down"'
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-up', 'py-up', 'py-down'])
self.assertMultilineMatches(bt,
r'''^.*
#[0-9]+ Frame 0x-?[0-9a-f]+, for file .*gdb_sample.py, line 7, in bar \(a=1, b=2, c=3\)
baz\(a, b, c\)
#[0-9]+ Frame 0x-?[0-9a-f]+, for file .*gdb_sample.py, line 10, in baz \(args=\(1, 2, 3\)\)
id\(42\)
$''')
class PyBtTests(DebuggerTests):
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
def test_bt(self):
'Verify that the "py-bt" command works'
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-bt'])
self.assertMultilineMatches(bt,
r'''^.*
Traceback \(most recent call first\):
<built-in method id of module object .*>
File ".*gdb_sample.py", line 10, in baz
id\(42\)
File ".*gdb_sample.py", line 7, in bar
baz\(a, b, c\)
File ".*gdb_sample.py", line 4, in foo
bar\(a, b, c\)
File ".*gdb_sample.py", line 12, in <module>
foo\(1, 2, 3\)
''')
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
def test_bt_full(self):
'Verify that the "py-bt-full" command works'
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-bt-full'])
self.assertMultilineMatches(bt,
r'''^.*
#[0-9]+ Frame 0x-?[0-9a-f]+, for file .*gdb_sample.py, line 7, in bar \(a=1, b=2, c=3\)
baz\(a, b, c\)
#[0-9]+ Frame 0x-?[0-9a-f]+, for file .*gdb_sample.py, line 4, in foo \(a=1, b=2, c=3\)
bar\(a, b, c\)
#[0-9]+ Frame 0x-?[0-9a-f]+, for file .*gdb_sample.py, line 12, in <module> \(\)
foo\(1, 2, 3\)
''')
def test_threads(self):
'Verify that "py-bt" indicates threads that are waiting for the GIL'
cmd = '''
from threading import Thread
class TestThread(Thread):
# These threads would run forever, but we'll interrupt things with the
# debugger
def run(self):
i = 0
while 1:
i += 1
t = {}
for i in range(4):
t[i] = TestThread()
t[i].start()
# Trigger a breakpoint on the main thread
id(42)
'''
# Verify with "py-bt":
gdb_output = self.get_stack_trace(cmd,
cmds_after_breakpoint=['thread apply all py-bt'])
self.assertIn('Waiting for the GIL', gdb_output)
# Verify with "py-bt-full":
gdb_output = self.get_stack_trace(cmd,
cmds_after_breakpoint=['thread apply all py-bt-full'])
self.assertIn('Waiting for the GIL', gdb_output)
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
# Some older versions of gdb will fail with
# "Cannot find new threads: generic error"
# unless we add LD_PRELOAD=PATH-TO-libpthread.so.1 as a workaround
def test_gc(self):
'Verify that "py-bt" indicates if a thread is garbage-collecting'
cmd = ('from gc import collect\n'
'id(42)\n'
'def foo():\n'
' collect()\n'
'def bar():\n'
' foo()\n'
'bar()\n')
# Verify with "py-bt":
gdb_output = self.get_stack_trace(cmd,
cmds_after_breakpoint=['break update_refs', 'continue', 'py-bt'],
)
self.assertIn('Garbage-collecting', gdb_output)
# Verify with "py-bt-full":
gdb_output = self.get_stack_trace(cmd,
cmds_after_breakpoint=['break update_refs', 'continue', 'py-bt-full'],
)
self.assertIn('Garbage-collecting', gdb_output)
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
# Some older versions of gdb will fail with
# "Cannot find new threads: generic error"
# unless we add LD_PRELOAD=PATH-TO-libpthread.so.1 as a workaround
#
# gdb will also generate many erroneous errors such as:
# Function "meth_varargs" not defined.
# This is because we are calling functions from an "external" module
# (_testcapimodule) rather than compiled-in functions. It seems difficult
# to suppress these. See also the comment in DebuggerTests.get_stack_trace
def test_pycfunction(self):
'Verify that "py-bt" displays invocations of PyCFunction instances'
# Various optimizations multiply the code paths by which these are
# called, so test a variety of calling conventions.
for func_name, args, expected_frame in (
('meth_varargs', '', 1),
('meth_varargs_keywords', '', 1),
('meth_o', '[]', 1),
('meth_noargs', '', 1),
('meth_fastcall', '', 1),
('meth_fastcall_keywords', '', 1),
):
for obj in (
'_testcapi',
'_testcapi.MethClass',
'_testcapi.MethClass()',
'_testcapi.MethStatic()',
# XXX: bound methods don't yet give nice tracebacks
# '_testcapi.MethInstance()',
):
with self.subTest(f'{obj}.{func_name}'):
cmd = textwrap.dedent(f'''
import _testcapi
def foo():
{obj}.{func_name}({args})
def bar():
foo()
bar()
''')
# Verify with "py-bt":
gdb_output = self.get_stack_trace(
cmd,
breakpoint=func_name,
cmds_after_breakpoint=['bt', 'py-bt'],
)
self.assertIn(f'<built-in method {func_name}', gdb_output)
# Verify with "py-bt-full":
gdb_output = self.get_stack_trace(
cmd,
breakpoint=func_name,
cmds_after_breakpoint=['py-bt-full'],
)
self.assertIn(
f'#{expected_frame} <built-in method {func_name}',
gdb_output,
)
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
def test_wrapper_call(self):
cmd = textwrap.dedent('''
class MyList(list):
def __init__(self):
super().__init__() # wrapper_call()
id("first break point")
l = MyList()
''')
cmds_after_breakpoint = ['break wrapper_call', 'continue']
if CET_PROTECTION:
# bpo-32962: same case as in get_stack_trace():
# we need an additional 'next' command in order to read
# arguments of the innermost function of the call stack.
cmds_after_breakpoint.append('next')
cmds_after_breakpoint.append('py-bt')
# Verify with "py-bt":
gdb_output = self.get_stack_trace(cmd,
cmds_after_breakpoint=cmds_after_breakpoint)
self.assertRegex(gdb_output,
r"<method-wrapper u?'__init__' of MyList object at ")
class PyPrintTests(DebuggerTests):
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
def test_basic_command(self):
'Verify that the "py-print" command works'
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-up', 'py-print args'])
self.assertMultilineMatches(bt,
r".*\nlocal 'args' = \(1, 2, 3\)\n.*")
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
@unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands")
def test_print_after_up(self):
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-up', 'py-up', 'py-print c', 'py-print b', 'py-print a'])
self.assertMultilineMatches(bt,
r".*\nlocal 'c' = 3\nlocal 'b' = 2\nlocal 'a' = 1\n.*")
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
def test_printing_global(self):
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-up', 'py-print __name__'])
self.assertMultilineMatches(bt,
r".*\nglobal '__name__' = '__main__'\n.*")
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
def test_printing_builtin(self):
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-up', 'py-print len'])
self.assertMultilineMatches(bt,
r".*\nbuiltin 'len' = <built-in method len of module object at remote 0x-?[0-9a-f]+>\n.*")
class PyLocalsTests(DebuggerTests):
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
def test_basic_command(self):
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-up', 'py-locals'])
self.assertMultilineMatches(bt,
r".*\nargs = \(1, 2, 3\)\n.*")
@unittest.skipUnless(HAS_PYUP_PYDOWN, "test requires py-up/py-down commands")
@unittest.skipIf(python_is_optimized(),
"Python was compiled with optimizations")
def test_locals_after_up(self):
bt = self.get_stack_trace(script=self.get_sample_script(),
cmds_after_breakpoint=['py-up', 'py-up', 'py-locals'])
self.assertMultilineMatches(bt,
r".*\na = 1\nb = 2\nc = 3\n.*")
def setUpModule():
if support.verbose:
print("GDB version %s.%s:" % (gdb_major_version, gdb_minor_version))
for line in gdb_version.splitlines():
print(" " * 4 + line)
if __name__ == "__main__":
unittest.main()
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