| # Written to test interrupted system calls interfering with our many buffered |
| # IO implementations. http://bugs.python.org/issue12268 |
| # |
| # This tests the '_io' module. Similar tests for Python 2.x's older |
| # default file I/O implementation exist within test_file2k.py. |
| # |
| # It was suggested that this code could be merged into test_io and the tests |
| # made to work using the same method as the existing signal tests in test_io. |
| # I was unable to get single process tests using alarm or setitimer that way |
| # to reproduce the EINTR problems. This process based test suite reproduces |
| # the problems prior to the issue12268 patch reliably on Linux and OSX. |
| # - gregory.p.smith |
| |
| import os |
| import select |
| import signal |
| import subprocess |
| import sys |
| from test.test_support import run_unittest |
| import time |
| import unittest |
| |
| # Test import all of the things we're about to try testing up front. |
| from _io import FileIO |
| |
| |
| @unittest.skipUnless(os.name == 'posix', 'tests requires a posix system.') |
| class TestFileIOSignalInterrupt(unittest.TestCase): |
| def setUp(self): |
| self._process = None |
| |
| def tearDown(self): |
| if self._process and self._process.poll() is None: |
| try: |
| self._process.kill() |
| except OSError: |
| pass |
| |
| def _generate_infile_setup_code(self): |
| """Returns the infile = ... line of code for the reader process. |
| |
| subclasseses should override this to test different IO objects. |
| """ |
| return ('import _io ;' |
| 'infile = _io.FileIO(sys.stdin.fileno(), "rb")') |
| |
| def fail_with_process_info(self, why, stdout=b'', stderr=b'', |
| communicate=True): |
| """A common way to cleanup and fail with useful debug output. |
| |
| Kills the process if it is still running, collects remaining output |
| and fails the test with an error message including the output. |
| |
| Args: |
| why: Text to go after "Error from IO process" in the message. |
| stdout, stderr: standard output and error from the process so |
| far to include in the error message. |
| communicate: bool, when True we call communicate() on the process |
| after killing it to gather additional output. |
| """ |
| if self._process.poll() is None: |
| time.sleep(0.1) # give it time to finish printing the error. |
| try: |
| self._process.terminate() # Ensure it dies. |
| except OSError: |
| pass |
| if communicate: |
| stdout_end, stderr_end = self._process.communicate() |
| stdout += stdout_end |
| stderr += stderr_end |
| self.fail('Error from IO process %s:\nSTDOUT:\n%sSTDERR:\n%s\n' % |
| (why, stdout.decode(), stderr.decode())) |
| |
| def _test_reading(self, data_to_write, read_and_verify_code): |
| """Generic buffered read method test harness to validate EINTR behavior. |
| |
| Also validates that Python signal handlers are run during the read. |
| |
| Args: |
| data_to_write: String to write to the child process for reading |
| before sending it a signal, confirming the signal was handled, |
| writing a final newline and closing the infile pipe. |
| read_and_verify_code: Single "line" of code to read from a file |
| object named 'infile' and validate the result. This will be |
| executed as part of a python subprocess fed data_to_write. |
| """ |
| infile_setup_code = self._generate_infile_setup_code() |
| # Total pipe IO in this function is smaller than the minimum posix OS |
| # pipe buffer size of 512 bytes. No writer should block. |
| assert len(data_to_write) < 512, 'data_to_write must fit in pipe buf.' |
| |
| # Start a subprocess to call our read method while handling a signal. |
| self._process = subprocess.Popen( |
| [sys.executable, '-u', '-c', |
| 'import io, signal, sys ;' |
| 'signal.signal(signal.SIGINT, ' |
| 'lambda s, f: sys.stderr.write("$\\n")) ;' |
| + infile_setup_code + ' ;' + |
| 'sys.stderr.write("Worm Sign!\\n") ;' |
| + read_and_verify_code + ' ;' + |
| 'infile.close()' |
| ], |
| stdin=subprocess.PIPE, stdout=subprocess.PIPE, |
| stderr=subprocess.PIPE) |
| |
| # Wait for the signal handler to be installed. |
| worm_sign = self._process.stderr.read(len(b'Worm Sign!\n')) |
| if worm_sign != b'Worm Sign!\n': # See also, Dune by Frank Herbert. |
| self.fail_with_process_info('while awaiting a sign', |
| stderr=worm_sign) |
| self._process.stdin.write(data_to_write) |
| |
| signals_sent = 0 |
| rlist = [] |
| # We don't know when the read_and_verify_code in our child is actually |
| # executing within the read system call we want to interrupt. This |
| # loop waits for a bit before sending the first signal to increase |
| # the likelihood of that. Implementations without correct EINTR |
| # and signal handling usually fail this test. |
| while not rlist: |
| rlist, _, _ = select.select([self._process.stderr], (), (), 0.05) |
| self._process.send_signal(signal.SIGINT) |
| signals_sent += 1 |
| if signals_sent > 200: |
| self._process.kill() |
| self.fail('reader process failed to handle our signals.') |
| # This assumes anything unexpected that writes to stderr will also |
| # write a newline. That is true of the traceback printing code. |
| signal_line = self._process.stderr.readline() |
| if signal_line != b'$\n': |
| self.fail_with_process_info('while awaiting signal', |
| stderr=signal_line) |
| |
| # We append a newline to our input so that a readline call can |
| # end on its own before the EOF is seen and so that we're testing |
| # the read call that was interrupted by a signal before the end of |
| # the data stream has been reached. |
| stdout, stderr = self._process.communicate(input=b'\n') |
| if self._process.returncode: |
| self.fail_with_process_info( |
| 'exited rc=%d' % self._process.returncode, |
| stdout, stderr, communicate=False) |
| # PASS! |
| |
| # String format for the read_and_verify_code used by read methods. |
| _READING_CODE_TEMPLATE = ( |
| 'got = infile.{read_method_name}() ;' |
| 'expected = {expected!r} ;' |
| 'assert got == expected, (' |
| '"{read_method_name} returned wrong data.\\n"' |
| '"got data %r\\nexpected %r" % (got, expected))' |
| ) |
| |
| def test_readline(self): |
| """readline() must handle signals and not lose data.""" |
| self._test_reading( |
| data_to_write=b'hello, world!', |
| read_and_verify_code=self._READING_CODE_TEMPLATE.format( |
| read_method_name='readline', |
| expected=b'hello, world!\n')) |
| |
| def test_readlines(self): |
| """readlines() must handle signals and not lose data.""" |
| self._test_reading( |
| data_to_write=b'hello\nworld!', |
| read_and_verify_code=self._READING_CODE_TEMPLATE.format( |
| read_method_name='readlines', |
| expected=[b'hello\n', b'world!\n'])) |
| |
| def test_readall(self): |
| """readall() must handle signals and not lose data.""" |
| self._test_reading( |
| data_to_write=b'hello\nworld!', |
| read_and_verify_code=self._READING_CODE_TEMPLATE.format( |
| read_method_name='readall', |
| expected=b'hello\nworld!\n')) |
| # read() is the same thing as readall(). |
| self._test_reading( |
| data_to_write=b'hello\nworld!', |
| read_and_verify_code=self._READING_CODE_TEMPLATE.format( |
| read_method_name='read', |
| expected=b'hello\nworld!\n')) |
| |
| |
| class TestBufferedIOSignalInterrupt(TestFileIOSignalInterrupt): |
| def _generate_infile_setup_code(self): |
| """Returns the infile = ... line of code to make a BufferedReader.""" |
| return ('infile = io.open(sys.stdin.fileno(), "rb") ;' |
| 'import _io ;assert isinstance(infile, _io.BufferedReader)') |
| |
| def test_readall(self): |
| """BufferedReader.read() must handle signals and not lose data.""" |
| self._test_reading( |
| data_to_write=b'hello\nworld!', |
| read_and_verify_code=self._READING_CODE_TEMPLATE.format( |
| read_method_name='read', |
| expected=b'hello\nworld!\n')) |
| |
| |
| class TestTextIOSignalInterrupt(TestFileIOSignalInterrupt): |
| def _generate_infile_setup_code(self): |
| """Returns the infile = ... line of code to make a TextIOWrapper.""" |
| return ('infile = io.open(sys.stdin.fileno(), "rt", newline=None) ;' |
| 'import _io ;assert isinstance(infile, _io.TextIOWrapper)') |
| |
| def test_readline(self): |
| """readline() must handle signals and not lose data.""" |
| self._test_reading( |
| data_to_write=b'hello, world!', |
| read_and_verify_code=self._READING_CODE_TEMPLATE.format( |
| read_method_name='readline', |
| expected='hello, world!\n')) |
| |
| def test_readlines(self): |
| """readlines() must handle signals and not lose data.""" |
| self._test_reading( |
| data_to_write=b'hello\r\nworld!', |
| read_and_verify_code=self._READING_CODE_TEMPLATE.format( |
| read_method_name='readlines', |
| expected=['hello\n', 'world!\n'])) |
| |
| def test_readall(self): |
| """read() must handle signals and not lose data.""" |
| self._test_reading( |
| data_to_write=b'hello\nworld!', |
| read_and_verify_code=self._READING_CODE_TEMPLATE.format( |
| read_method_name='read', |
| expected="hello\nworld!\n")) |
| |
| |
| def test_main(): |
| test_cases = [ |
| tc for tc in globals().values() |
| if isinstance(tc, type) and issubclass(tc, unittest.TestCase)] |
| run_unittest(*test_cases) |
| |
| |
| if __name__ == '__main__': |
| test_main() |
