253 lines
11 KiB
Python
253 lines
11 KiB
Python
|
# Written to test interrupted system calls interfering with our many buffered
|
||
|
|
# IO implementations. http://bugs.python.org/issue12268
|
||
|
|
#
|
||
|
|
# 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
|
||
|
|
import time
|
||
|
|
import unittest
|
||
|
|
|
||
|
|
# Test import all of the things we're about to try testing up front.
|
||
|
|
import _io
|
||
|
|
import _pyio
|
||
|
|
|
||
|
|
|
||
|
|
@unittest.skipUnless(os.name == 'posix', 'tests requires a posix system.')
|
||
|
|
class TestFileIOSignalInterrupt:
|
||
|
|
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 %s as io ;'
|
||
|
|
'infile = io.FileIO(sys.stdin.fileno(), "rb")' %
|
||
|
|
self.modname)
|
||
|
|
|
||
|
|
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 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 CTestFileIOSignalInterrupt(TestFileIOSignalInterrupt, unittest.TestCase):
|
||
|
|
modname = '_io'
|
||
|
|
|
||
|
|
class PyTestFileIOSignalInterrupt(TestFileIOSignalInterrupt, unittest.TestCase):
|
||
|
|
modname = '_pyio'
|
||
|
|
|
||
|
|
|
||
|
|
class TestBufferedIOSignalInterrupt(TestFileIOSignalInterrupt):
|
||
|
|
def _generate_infile_setup_code(self):
|
||
|
|
"""Returns the infile = ... line of code to make a BufferedReader."""
|
||
|
|
return ('import %s as io ;infile = io.open(sys.stdin.fileno(), "rb") ;'
|
||
|
|
'assert isinstance(infile, io.BufferedReader)' %
|
||
|
|
self.modname)
|
||
|
|
|
||
|
|
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 CTestBufferedIOSignalInterrupt(TestBufferedIOSignalInterrupt, unittest.TestCase):
|
||
|
|
modname = '_io'
|
||
|
|
|
||
|
|
class PyTestBufferedIOSignalInterrupt(TestBufferedIOSignalInterrupt, unittest.TestCase):
|
||
|
|
modname = '_pyio'
|
||
|
|
|
||
|
|
|
||
|
|
class TestTextIOSignalInterrupt(TestFileIOSignalInterrupt):
|
||
|
|
def _generate_infile_setup_code(self):
|
||
|
|
"""Returns the infile = ... line of code to make a TextIOWrapper."""
|
||
|
|
return ('import %s as io ;'
|
||
|
|
'infile = io.open(sys.stdin.fileno(), "rt", newline=None) ;'
|
||
|
|
'assert isinstance(infile, io.TextIOWrapper)' %
|
||
|
|
self.modname)
|
||
|
|
|
||
|
|
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"))
|
||
|
|
|
||
|
|
class CTestTextIOSignalInterrupt(TestTextIOSignalInterrupt, unittest.TestCase):
|
||
|
|
modname = '_io'
|
||
|
|
|
||
|
|
class PyTestTextIOSignalInterrupt(TestTextIOSignalInterrupt, unittest.TestCase):
|
||
|
|
modname = '_pyio'
|
||
|
|
|
||
|
|
|
||
|
|
if __name__ == '__main__':
|
||
|
|
unittest.main()
|