cpython/Lib/test/test_pty.py at e990b7980043f06789777f970111c11c41fe2588 · 8vasu/cpython

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from test.support import verbose, reap_children

from test.support.import_helper import import_module

# Skip these tests if termios is not available

import_module('termios')

import errno

import pty

import os

import sys

import select

import signal

import socket

import io # readline

import unittest

import struct

import tty

import fcntl

import platform

import warnings

TEST_STRING_1 = b"I wish to buy a fish license.\n"

TEST_STRING_2 = b"For my pet fish, Eric.\n"

try:

_TIOCGWINSZ = tty.TIOCGWINSZ

_TIOCSWINSZ = tty.TIOCSWINSZ

_HAVE_WINSZ = True

except AttributeError:

_HAVE_WINSZ = False

if verbose:

def debug(msg):

print(msg)

else:

def debug(msg):

pass

# Note that os.read() is nondeterministic so we need to be very careful

# to make the test suite deterministic. A normal call to os.read() may

# give us less than expected.

# Beware, on my Linux system, if I put 'foo\n' into a terminal fd, I get

# back 'foo\r\n' at the other end. The behavior depends on the termios

# setting. The newline translation may be OS-specific. To make the

# test suite deterministic and OS-independent, the functions _readline

# and normalize_output can be used.

def normalize_output(data):

# Some operating systems do conversions on newline. We could possibly fix

# that by doing the appropriate termios.tcsetattr()s. I couldn't figure out

# the right combo on Tru64. So, just normalize the output and doc the

# problem O/Ses by allowing certain combinations for some platforms, but

# avoid allowing other differences (like extra whitespace, trailing garbage,

# etc.)

# This is about the best we can do without getting some feedback

# from someone more knowledgable.

# OSF/1 (Tru64) apparently turns \n into \r\r\n.

if data.endswith(b'\r\r\n'):

return data.replace(b'\r\r\n', b'\n')

if data.endswith(b'\r\n'):

return data.replace(b'\r\n', b'\n')

return data

def _readline(fd):

"""Read one line. May block forever if no newline is read."""

reader = io.FileIO(fd, mode='rb', closefd=False)

return reader.readline()

def expectedFailureIfStdinIsTTY(fun):

# avoid isatty() for now

try:

tty.tcgetattr(pty.STDIN_FILENO)

return unittest.expectedFailure(fun)

except tty.error:

pass

return fun

def expectedFailureOnBSD(fun):

PLATFORM = platform.system()

if PLATFORM.endswith("BSD") or PLATFORM == "Darwin":

return unittest.expectedFailure(fun)

return fun

def _get_term_winsz(fd):

s = struct.pack("HHHH", 0, 0, 0, 0)

return fcntl.ioctl(fd, _TIOCGWINSZ, s)

def _set_term_winsz(fd, winsz):

fcntl.ioctl(fd, _TIOCSWINSZ, winsz)

# Marginal testing of pty suite. Cannot do extensive 'do or fail' testing

# because pty code is not too portable.

# XXX(nnorwitz): these tests leak fds when there is an error.

class PtyTest(unittest.TestCase):

def setUp(self):

old_alarm = signal.signal(signal.SIGALRM, self.handle_sig)

self.addCleanup(signal.signal, signal.SIGALRM, old_alarm)

old_sighup = signal.signal(signal.SIGHUP, self.handle_sighup)

self.addCleanup(signal.signal, signal.SIGHUP, old_sighup)

# isatty() and close() can hang on some platforms. Set an alarm

# before running the test to make sure we don't hang forever.

self.addCleanup(signal.alarm, 0)

signal.alarm(10)

# Save original stdin window size

self.stdin_rows = None

self.stdin_cols = None

if _HAVE_WINSZ:

try:

stdin_dim = os.get_terminal_size(pty.STDIN_FILENO)

self.stdin_rows = stdin_dim.lines

self.stdin_cols = stdin_dim.columns

old_stdin_winsz = struct.pack("HHHH", self.stdin_rows,

self.stdin_cols, 0, 0)

self.addCleanup(_set_term_winsz, pty.STDIN_FILENO, old_stdin_winsz)

except OSError:

pass

def handle_sig(self, sig, frame):

self.fail("isatty hung")

@staticmethod

def handle_sighup(signum, frame):

# bpo-38547: if the process is the session leader, os.close(master_fd)

# of "master_fd, slave_name = pty.master_open()" raises SIGHUP

# signal: just ignore the signal.

# NOTE: the above comment is from an older version of the test;

# master_open() is not being used anymore.

pass

@expectedFailureIfStdinIsTTY

def test_openpty(self):

try:

mode = tty.tcgetattr(pty.STDIN_FILENO)

except tty.error:

# not a tty or bad/closed fd

debug("tty.tcgetattr(pty.STDIN_FILENO) failed")

mode = None

new_stdin_winsz = None

if self.stdin_rows != None and self.stdin_cols != None:

try:

debug("Setting pty.STDIN_FILENO window size")

# Set number of columns and rows to be the

# floors of 1/5 of respective original values

target_stdin_winsz = struct.pack("HHHH", self.stdin_rows//5,

self.stdin_cols//5, 0, 0)

_set_term_winsz(pty.STDIN_FILENO, target_stdin_winsz)

# Were we able to set the window size

# of pty.STDIN_FILENO successfully?

new_stdin_winsz = _get_term_winsz(pty.STDIN_FILENO)

self.assertEqual(new_stdin_winsz, target_stdin_winsz,

"pty.STDIN_FILENO window size unchanged")

except OSError:

warnings.warn("Failed to set pty.STDIN_FILENO window size")

pass

try:

debug("Calling pty.openpty()")

try:

master_fd, slave_fd = pty.openpty(mode, new_stdin_winsz)

except TypeError:

master_fd, slave_fd = pty.openpty()

debug(f"Got master_fd '{master_fd}', slave_fd '{slave_fd}'")

except OSError:

# " An optional feature could not be imported " ... ?

raise unittest.SkipTest("Pseudo-terminals (seemingly) not functional.")

self.assertTrue(os.isatty(slave_fd), "slave_fd is not a tty")

if mode:

self.assertEqual(tty.tcgetattr(slave_fd), mode,

"openpty() failed to set slave termios")

if new_stdin_winsz:

self.assertEqual(_get_term_winsz(slave_fd), new_stdin_winsz,

"openpty() failed to set slave window size")

# Solaris requires reading the fd before anything is returned.

# My guess is that since we open and close the slave fd

# in master_open(), we need to read the EOF.

# NOTE: the above comment is from an older version of the test;

# master_open() is not being used anymore.

# Ensure the fd is non-blocking in case there's nothing to read.

blocking = os.get_blocking(master_fd)

try:

os.set_blocking(master_fd, False)

try:

s1 = os.read(master_fd, 1024)

self.assertEqual(b'', s1)

except OSError as e:

if e.errno != errno.EAGAIN:

raise

finally:

# Restore the original flags.

os.set_blocking(master_fd, blocking)

debug("Writing to slave_fd")

os.write(slave_fd, TEST_STRING_1)

s1 = _readline(master_fd)

self.assertEqual(b'I wish to buy a fish license.\n',

normalize_output(s1))

debug("Writing chunked output")

os.write(slave_fd, TEST_STRING_2[:5])

os.write(slave_fd, TEST_STRING_2[5:])

s2 = _readline(master_fd)

self.assertEqual(b'For my pet fish, Eric.\n', normalize_output(s2))

os.close(slave_fd)

# closing master_fd can raise a SIGHUP if the process is

# the session leader: we installed a SIGHUP signal handler

# to ignore this signal.

os.close(master_fd)

def test_fork(self):

debug("calling pty.fork()")

pid, master_fd = pty.fork()

if pid == pty.CHILD:

# stdout should be connected to a tty.

if not os.isatty(1):

debug("Child's fd 1 is not a tty?!")

os._exit(3)

# After pty.fork(), the child should already be a session leader.

# (on those systems that have that concept.)

debug("In child, calling os.setsid()")

try:

os.setsid()

except OSError:

# Good, we already were session leader

debug("Good: OSError was raised.")

pass

except AttributeError:

# Have pty, but not setsid()?

debug("No setsid() available?")

pass

except:

# We don't want this error to propagate, escaping the call to

# os._exit() and causing very peculiar behavior in the calling

# regrtest.py !

# Note: could add traceback printing here.

debug("An unexpected error was raised.")

os._exit(1)

else:

debug("os.setsid() succeeded! (bad!)")

os._exit(2)

os._exit(4)

else:

debug("Waiting for child (%d) to finish." % pid)

# In verbose mode, we have to consume the debug output from the

# child or the child will block, causing this test to hang in the

# parent's waitpid() call. The child blocks after a

# platform-dependent amount of data is written to its fd. On

# Linux 2.6, it's 4000 bytes and the child won't block, but on OS

# X even the small writes in the child above will block it. Also

# on Linux, the read() will raise an OSError (input/output error)

# when it tries to read past the end of the buffer but the child's

# already exited, so catch and discard those exceptions. It's not

# worth checking for EIO.

while True:

try:

data = os.read(master_fd, 80)

except OSError:

break

if not data:

break

sys.stdout.write(str(data.replace(b'\r\n', b'\n'),

encoding='ascii'))

##line = os.read(master_fd, 80)

##lines = line.replace('\r\n', '\n').split('\n')

##if False and lines != ['In child, calling os.setsid()',

## 'Good: OSError was raised.', '']:

## raise TestFailed("Unexpected output from child: %r" % line)

(pid, status) = os.waitpid(pid, 0)

res = os.waitstatus_to_exitcode(status)

debug("Child (%d) exited with code %d (status %d)." % (pid, res, status))

if res == 1:

self.fail("Child raised an unexpected exception in os.setsid()")

elif res == 2:

self.fail("pty.fork() failed to make child a session leader.")

elif res == 3:

self.fail("Child spawned by pty.fork() did not have a tty as stdout")

elif res != 4:

self.fail("pty.fork() failed for unknown reasons.")

##debug("Reading from master_fd now that the child has exited")

##try:

## s1 = os.read(master_fd, 1024)

##except OSError:

## pass

##else:

## raise TestFailed("Read from master_fd did not raise exception")

os.close(master_fd)

@expectedFailureOnBSD

def test_master_read(self):

debug("Calling pty.openpty()")

master_fd, slave_fd = pty.openpty()

debug(f"Got master_fd '{master_fd}', slave_fd '{slave_fd}'")

debug("Closing slave_fd")

os.close(slave_fd)

debug("Reading from master_fd")

with self.assertRaises(OSError):

os.read(master_fd, 1)

os.close(master_fd)

class SmallPtyTests(unittest.TestCase):

"""These tests don't spawn children or hang."""

def setUp(self):

self.orig_stdin_fileno = pty.STDIN_FILENO

self.orig_stdout_fileno = pty.STDOUT_FILENO

self.orig_pty_select = pty.select

self.fds = [] # A list of file descriptors to close.

self.files = []

self.select_rfds_lengths = []

self.select_rfds_results = []

def tearDown(self):

pty.STDIN_FILENO = self.orig_stdin_fileno

pty.STDOUT_FILENO = self.orig_stdout_fileno

pty.select = self.orig_pty_select

for file in self.files:

try:

file.close()

except OSError:

pass

for fd in self.fds:

try:

os.close(fd)

except OSError:

pass

def _pipe(self):

pipe_fds = os.pipe()

self.fds.extend(pipe_fds)

return pipe_fds

def _socketpair(self):

socketpair = socket.socketpair()

self.files.extend(socketpair)

return socketpair

def _mock_select(self, rfds, wfds, xfds, timeout=0):

# This will raise IndexError when no more expected calls exist.

# This ignores the timeout

self.assertEqual(self.select_rfds_lengths.pop(0), len(rfds))

return self.select_rfds_results.pop(0), [], []

def test__copy_to_each(self):

"""Test the normal data case on both master_fd and stdin."""

read_from_stdout_fd, mock_stdout_fd = self._pipe()

pty.STDOUT_FILENO = mock_stdout_fd

mock_stdin_fd, write_to_stdin_fd = self._pipe()

pty.STDIN_FILENO = mock_stdin_fd

socketpair = self._socketpair()

masters = [s.fileno() for s in socketpair]

# Feed data. Smaller than PIPEBUF. These writes will not block.

os.write(masters[1], b'from master')

os.write(write_to_stdin_fd, b'from stdin')

# Expect two select calls, the last one will cause IndexError

pty.select = self._mock_select

self.select_rfds_lengths.append(2)

self.select_rfds_results.append([mock_stdin_fd, masters[0]])

self.select_rfds_lengths.append(2)

with self.assertRaises(IndexError):

pty._copy(masters[0])

# Test that the right data went to the right places.

rfds = select.select([read_from_stdout_fd, masters[1]], [], [], 0)[0]

self.assertEqual([read_from_stdout_fd, masters[1]], rfds)

self.assertEqual(os.read(read_from_stdout_fd, 20), b'from master')

self.assertEqual(os.read(masters[1], 20), b'from stdin')

def test__copy_eof_on_all(self):

"""Test the empty read EOF case on both master_fd and stdin."""

read_from_stdout_fd, mock_stdout_fd = self._pipe()

pty.STDOUT_FILENO = mock_stdout_fd

mock_stdin_fd, write_to_stdin_fd = self._pipe()

pty.STDIN_FILENO = mock_stdin_fd

socketpair = self._socketpair()

masters = [s.fileno() for s in socketpair]

socketpair[1].close()

os.close(write_to_stdin_fd)

# Expect two select calls, the last one will cause IndexError

pty.select = self._mock_select

self.select_rfds_lengths.append(2)

self.select_rfds_results.append([mock_stdin_fd, masters[0]])

# We expect that both fds were removed from the fds list as they

# both encountered an EOF before the second select call.

self.select_rfds_lengths.append(0)

with self.assertRaises(IndexError):

pty._copy(masters[0])

def tearDownModule():

reap_children()

if __name__ == "__main__":

unittest.main()

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