from contextlib import contextmanager import datetime import faulthandler import os import re import signal import subprocess import sys from test import support, script_helper from test.script_helper import assert_python_ok import tempfile import unittest from textwrap import dedent try: import threading HAVE_THREADS = True except ImportError: HAVE_THREADS = False TIMEOUT = 0.5 def expected_traceback(lineno1, lineno2, header, min_count=1): regex = header regex += ' File "", line %s in func\n' % lineno1 regex += ' File "", line %s in ' % lineno2 if 1 < min_count: return '^' + (regex + '\n') * (min_count - 1) + regex else: return '^' + regex + '$' @contextmanager def temporary_filename(): filename = tempfile.mktemp() try: yield filename finally: support.unlink(filename) class FaultHandlerTests(unittest.TestCase): def get_output(self, code, filename=None): """ Run the specified code in Python (in a new child process) and read the output from the standard error or from a file (if filename is set). Return the output lines as a list. Strip the reference count from the standard error for Python debug build, and replace "Current thread 0x00007f8d8fbd9700" by "Current thread XXX". """ code = dedent(code).strip() with support.SuppressCrashReport(): process = script_helper.spawn_python('-c', code) stdout, stderr = process.communicate() exitcode = process.wait() output = support.strip_python_stderr(stdout) output = output.decode('ascii', 'backslashreplace') if filename: self.assertEqual(output, '') with open(filename, "rb") as fp: output = fp.read() output = output.decode('ascii', 'backslashreplace') output = re.sub('Current thread 0x[0-9a-f]+', 'Current thread XXX', output) return output.splitlines(), exitcode def check_fatal_error(self, code, line_number, name_regex, filename=None, all_threads=True, other_regex=None): """ Check that the fault handler for fatal errors is enabled and check the traceback from the child process output. Raise an error if the output doesn't match the expected format. """ if all_threads: header = 'Current thread XXX (most recent call first)' else: header = 'Stack (most recent call first)' regex = """ ^Fatal Python error: {name} {header}: File "", line {lineno} in """ regex = dedent(regex.format( lineno=line_number, name=name_regex, header=re.escape(header))).strip() if other_regex: regex += '|' + other_regex output, exitcode = self.get_output(code, filename) output = '\n'.join(output) self.assertRegex(output, regex) self.assertNotEqual(exitcode, 0) @unittest.skipIf(sys.platform.startswith('aix'), "the first page of memory is a mapped read-only on AIX") def test_read_null(self): self.check_fatal_error(""" import faulthandler faulthandler.enable() faulthandler._read_null() """, 3, # Issue #12700: Read NULL raises SIGILL on Mac OS X Lion '(?:Segmentation fault|Bus error|Illegal instruction)') def test_sigsegv(self): self.check_fatal_error(""" import faulthandler faulthandler.enable() faulthandler._sigsegv() """, 3, 'Segmentation fault') def test_sigabrt(self): self.check_fatal_error(""" import faulthandler faulthandler.enable() faulthandler._sigabrt() """, 3, 'Aborted') @unittest.skipIf(sys.platform == 'win32', "SIGFPE cannot be caught on Windows") def test_sigfpe(self): self.check_fatal_error(""" import faulthandler faulthandler.enable() faulthandler._sigfpe() """, 3, 'Floating point exception') @unittest.skipIf(not hasattr(faulthandler, '_sigbus'), "need faulthandler._sigbus()") def test_sigbus(self): self.check_fatal_error(""" import faulthandler faulthandler.enable() faulthandler._sigbus() """, 3, 'Bus error') @unittest.skipIf(not hasattr(faulthandler, '_sigill'), "need faulthandler._sigill()") def test_sigill(self): self.check_fatal_error(""" import faulthandler faulthandler.enable() faulthandler._sigill() """, 3, 'Illegal instruction') def test_fatal_error(self): self.check_fatal_error(""" import faulthandler faulthandler._fatal_error(b'xyz') """, 2, 'xyz') @unittest.skipIf(sys.platform.startswith('openbsd') and HAVE_THREADS, "Issue #12868: sigaltstack() doesn't work on " "OpenBSD if Python is compiled with pthread") @unittest.skipIf(not hasattr(faulthandler, '_stack_overflow'), 'need faulthandler._stack_overflow()') def test_stack_overflow(self): self.check_fatal_error(""" import faulthandler faulthandler.enable() faulthandler._stack_overflow() """, 3, '(?:Segmentation fault|Bus error)', other_regex='unable to raise a stack overflow') def test_gil_released(self): self.check_fatal_error(""" import faulthandler faulthandler.enable() faulthandler._sigsegv(True) """, 3, 'Segmentation fault') def test_enable_file(self): with temporary_filename() as filename: self.check_fatal_error(""" import faulthandler output = open({filename}, 'wb') faulthandler.enable(output) faulthandler._sigsegv() """.format(filename=repr(filename)), 4, 'Segmentation fault', filename=filename) def test_enable_single_thread(self): self.check_fatal_error(""" import faulthandler faulthandler.enable(all_threads=False) faulthandler._sigsegv() """, 3, 'Segmentation fault', all_threads=False) def test_disable(self): code = """ import faulthandler faulthandler.enable() faulthandler.disable() faulthandler._sigsegv() """ not_expected = 'Fatal Python error' stderr, exitcode = self.get_output(code) stderr = '\n'.join(stderr) self.assertTrue(not_expected not in stderr, "%r is present in %r" % (not_expected, stderr)) self.assertNotEqual(exitcode, 0) def test_is_enabled(self): orig_stderr = sys.stderr try: # regrtest may replace sys.stderr by io.StringIO object, but # faulthandler.enable() requires that sys.stderr has a fileno() # method sys.stderr = sys.__stderr__ was_enabled = faulthandler.is_enabled() try: faulthandler.enable() self.assertTrue(faulthandler.is_enabled()) faulthandler.disable() self.assertFalse(faulthandler.is_enabled()) finally: if was_enabled: faulthandler.enable() else: faulthandler.disable() finally: sys.stderr = orig_stderr def test_disabled_by_default(self): # By default, the module should be disabled code = "import faulthandler; print(faulthandler.is_enabled())" args = (sys.executable, '-E', '-c', code) # don't use assert_python_ok() because it always enable faulthandler output = subprocess.check_output(args) self.assertEqual(output.rstrip(), b"False") def test_sys_xoptions(self): # Test python -X faulthandler code = "import faulthandler; print(faulthandler.is_enabled())" args = (sys.executable, "-E", "-X", "faulthandler", "-c", code) # don't use assert_python_ok() because it always enable faulthandler output = subprocess.check_output(args) self.assertEqual(output.rstrip(), b"True") def test_env_var(self): # empty env var code = "import faulthandler; print(faulthandler.is_enabled())" args = (sys.executable, "-c", code) env = os.environ.copy() env['PYTHONFAULTHANDLER'] = '' # don't use assert_python_ok() because it always enable faulthandler output = subprocess.check_output(args, env=env) self.assertEqual(output.rstrip(), b"False") # non-empty env var env = os.environ.copy() env['PYTHONFAULTHANDLER'] = '1' output = subprocess.check_output(args, env=env) self.assertEqual(output.rstrip(), b"True") def check_dump_traceback(self, filename): """ Explicitly call dump_traceback() function and check its output. Raise an error if the output doesn't match the expected format. """ code = """ import faulthandler def funcB(): if {has_filename}: with open({filename}, "wb") as fp: faulthandler.dump_traceback(fp, all_threads=False) else: faulthandler.dump_traceback(all_threads=False) def funcA(): funcB() funcA() """ code = code.format( filename=repr(filename), has_filename=bool(filename), ) if filename: lineno = 6 else: lineno = 8 expected = [ 'Stack (most recent call first):', ' File "", line %s in funcB' % lineno, ' File "", line 11 in funcA', ' File "", line 13 in ' ] trace, exitcode = self.get_output(code, filename) self.assertEqual(trace, expected) self.assertEqual(exitcode, 0) def test_dump_traceback(self): self.check_dump_traceback(None) def test_dump_traceback_file(self): with temporary_filename() as filename: self.check_dump_traceback(filename) def test_truncate(self): maxlen = 500 func_name = 'x' * (maxlen + 50) truncated = 'x' * maxlen + '...' code = """ import faulthandler def {func_name}(): faulthandler.dump_traceback(all_threads=False) {func_name}() """ code = code.format( func_name=func_name, ) expected = [ 'Stack (most recent call first):', ' File "", line 4 in %s' % truncated, ' File "", line 6 in ' ] trace, exitcode = self.get_output(code) self.assertEqual(trace, expected) self.assertEqual(exitcode, 0) @unittest.skipIf(not HAVE_THREADS, 'need threads') def check_dump_traceback_threads(self, filename): """ Call explicitly dump_traceback(all_threads=True) and check the output. Raise an error if the output doesn't match the expected format. """ code = """ import faulthandler from threading import Thread, Event import time def dump(): if {filename}: with open({filename}, "wb") as fp: faulthandler.dump_traceback(fp, all_threads=True) else: faulthandler.dump_traceback(all_threads=True) class Waiter(Thread): # avoid blocking if the main thread raises an exception. daemon = True def __init__(self): Thread.__init__(self) self.running = Event() self.stop = Event() def run(self): self.running.set() self.stop.wait() waiter = Waiter() waiter.start() waiter.running.wait() dump() waiter.stop.set() waiter.join() """ code = code.format(filename=repr(filename)) output, exitcode = self.get_output(code, filename) output = '\n'.join(output) if filename: lineno = 8 else: lineno = 10 regex = """ ^Thread 0x[0-9a-f]+ \(most recent call first\): (?: File ".*threading.py", line [0-9]+ in [_a-z]+ ){{1,3}} File "", line 23 in run File ".*threading.py", line [0-9]+ in _bootstrap_inner File ".*threading.py", line [0-9]+ in _bootstrap Current thread XXX \(most recent call first\): File "", line {lineno} in dump File "", line 28 in $ """ regex = dedent(regex.format(lineno=lineno)).strip() self.assertRegex(output, regex) self.assertEqual(exitcode, 0) def test_dump_traceback_threads(self): self.check_dump_traceback_threads(None) def test_dump_traceback_threads_file(self): with temporary_filename() as filename: self.check_dump_traceback_threads(filename) def _check_dump_traceback_later(self, repeat, cancel, filename, loops): """ Check how many times the traceback is written in timeout x 2.5 seconds, or timeout x 3.5 seconds if cancel is True: 1, 2 or 3 times depending on repeat and cancel options. Raise an error if the output doesn't match the expect format. """ timeout_str = str(datetime.timedelta(seconds=TIMEOUT)) code = """ import faulthandler import time def func(timeout, repeat, cancel, file, loops): for loop in range(loops): faulthandler.dump_traceback_later(timeout, repeat=repeat, file=file) if cancel: faulthandler.cancel_dump_traceback_later() time.sleep(timeout * 5) faulthandler.cancel_dump_traceback_later() timeout = {timeout} repeat = {repeat} cancel = {cancel} loops = {loops} if {has_filename}: file = open({filename}, "wb") else: file = None func(timeout, repeat, cancel, file, loops) if file is not None: file.close() """ code = code.format( timeout=TIMEOUT, repeat=repeat, cancel=cancel, loops=loops, has_filename=bool(filename), filename=repr(filename), ) trace, exitcode = self.get_output(code, filename) trace = '\n'.join(trace) if not cancel: count = loops if repeat: count *= 2 header = r'Timeout \(%s\)!\nThread 0x[0-9a-f]+ \(most recent call first\):\n' % timeout_str regex = expected_traceback(9, 20, header, min_count=count) self.assertRegex(trace, regex) else: self.assertEqual(trace, '') self.assertEqual(exitcode, 0) @unittest.skipIf(not hasattr(faulthandler, 'dump_traceback_later'), 'need faulthandler.dump_traceback_later()') def check_dump_traceback_later(self, repeat=False, cancel=False, file=False, twice=False): if twice: loops = 2 else: loops = 1 if file: with temporary_filename() as filename: self._check_dump_traceback_later(repeat, cancel, filename, loops) else: self._check_dump_traceback_later(repeat, cancel, None, loops) def test_dump_traceback_later(self): self.check_dump_traceback_later() def test_dump_traceback_later_repeat(self): self.check_dump_traceback_later(repeat=True) def test_dump_traceback_later_cancel(self): self.check_dump_traceback_later(cancel=True) def test_dump_traceback_later_file(self): self.check_dump_traceback_later(file=True) def test_dump_traceback_later_twice(self): self.check_dump_traceback_later(twice=True) @unittest.skipIf(not hasattr(faulthandler, "register"), "need faulthandler.register") def check_register(self, filename=False, all_threads=False, unregister=False, chain=False): """ Register a handler displaying the traceback on a user signal. Raise the signal and check the written traceback. If chain is True, check that the previous signal handler is called. Raise an error if the output doesn't match the expected format. """ signum = signal.SIGUSR1 code = """ import faulthandler import os import signal import sys def func(signum): os.kill(os.getpid(), signum) def handler(signum, frame): handler.called = True handler.called = False exitcode = 0 signum = {signum} unregister = {unregister} chain = {chain} if {has_filename}: file = open({filename}, "wb") else: file = None if chain: signal.signal(signum, handler) faulthandler.register(signum, file=file, all_threads={all_threads}, chain={chain}) if unregister: faulthandler.unregister(signum) func(signum) if chain and not handler.called: if file is not None: output = file else: output = sys.stderr print("Error: signal handler not called!", file=output) exitcode = 1 if file is not None: file.close() sys.exit(exitcode) """ code = code.format( filename=repr(filename), has_filename=bool(filename), all_threads=all_threads, signum=signum, unregister=unregister, chain=chain, ) trace, exitcode = self.get_output(code, filename) trace = '\n'.join(trace) if not unregister: if all_threads: regex = 'Current thread XXX \(most recent call first\):\n' else: regex = 'Stack \(most recent call first\):\n' regex = expected_traceback(7, 28, regex) self.assertRegex(trace, regex) else: self.assertEqual(trace, '') if unregister: self.assertNotEqual(exitcode, 0) else: self.assertEqual(exitcode, 0) def test_register(self): self.check_register() def test_unregister(self): self.check_register(unregister=True) def test_register_file(self): with temporary_filename() as filename: self.check_register(filename=filename) def test_register_threads(self): self.check_register(all_threads=True) def test_register_chain(self): self.check_register(chain=True) @contextmanager def check_stderr_none(self): stderr = sys.stderr try: sys.stderr = None with self.assertRaises(RuntimeError) as cm: yield self.assertEqual(str(cm.exception), "sys.stderr is None") finally: sys.stderr = stderr def test_stderr_None(self): # Issue #21497: provide an helpful error if sys.stderr is None, # instead of just an attribute error: "None has no attribute fileno". with self.check_stderr_none(): faulthandler.enable() with self.check_stderr_none(): faulthandler.dump_traceback() if hasattr(faulthandler, 'dump_traceback_later'): with self.check_stderr_none(): faulthandler.dump_traceback_later(1e-3) if hasattr(faulthandler, "register"): with self.check_stderr_none(): faulthandler.register(signal.SIGUSR1) if __name__ == "__main__": unittest.main()