summaryrefslogtreecommitdiffstats
path: root/Lib/test/test_pty.py
blob: 51e3a46d0df178072ccbb8973a94fcc4ed926512 (plain)
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
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
from test.support import verbose, reap_children
from test.support.os_helper import TESTFN, unlink
from test.support.import_helper import import_module

# Skip these tests if termios or fcntl are not available
import_module('termios')
# fcntl is a proxy for not being one of the wasm32 platforms even though we
# don't use this module... a proper check for what crashes those is needed.
import_module("fcntl")

import errno
import os
import pty
import tty
import sys
import select
import signal
import socket
import io # readline
import unittest
import warnings

TEST_STRING_1 = b"I wish to buy a fish license.\n"
TEST_STRING_2 = b"For my pet fish, Eric.\n"

_HAVE_WINSZ = hasattr(tty, "TIOCGWINSZ") and hasattr(tty, "TIOCSWINSZ")

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()
    try:
        tty.tcgetattr(pty.STDIN_FILENO)
        return unittest.expectedFailure(fun)
    except tty.error:
        pass
    return fun


def write_all(fd, data):
    written = os.write(fd, data)
    if written != len(data):
        # gh-73256, gh-110673: It should never happen, but check just in case
        raise Exception(f"short write: os.write({fd}, {len(data)} bytes) "
                        f"wrote {written} bytes")


# Marginal testing of pty suite. Cannot do extensive 'do or fail' testing
# because pty code is not too portable.
class PtyTest(unittest.TestCase):
    def setUp(self):
        old_sighup = signal.signal(signal.SIGHUP, self.handle_sighup)
        self.addCleanup(signal.signal, signal.SIGHUP, old_sighup)

        # Save original stdin window size.
        self.stdin_dim = None
        if _HAVE_WINSZ:
            try:
                self.stdin_dim = tty.tcgetwinsize(pty.STDIN_FILENO)
                self.addCleanup(tty.tcsetwinsize, pty.STDIN_FILENO,
                                self.stdin_dim)
            except tty.error:
                pass

    @staticmethod
    def handle_sighup(signum, frame):
        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_dim = None
        if self.stdin_dim:
            try:
                # Modify pty.STDIN_FILENO window size; we need to
                # check if pty.openpty() is able to set pty slave
                # window size accordingly.
                debug("Setting pty.STDIN_FILENO window size.")
                debug(f"original size: (row, col) = {self.stdin_dim}")
                target_dim = (self.stdin_dim[0] + 1, self.stdin_dim[1] + 1)
                debug(f"target size: (row, col) = {target_dim}")
                tty.tcsetwinsize(pty.STDIN_FILENO, target_dim)

                # Were we able to set the window size
                # of pty.STDIN_FILENO successfully?
                new_dim = tty.tcgetwinsize(pty.STDIN_FILENO)
                self.assertEqual(new_dim, target_dim,
                                 "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, slave_name = pty.openpty(mode, new_dim,
                                                              True)
            except TypeError:
                master_fd, slave_fd = pty.openpty()
                slave_name = None
            debug(f"Got {master_fd=}, {slave_fd=}, {slave_name=}")
        except OSError:
            # " An optional feature could not be imported " ... ?
            raise unittest.SkipTest("Pseudo-terminals (seemingly) not functional.")

        # closing master_fd can raise a SIGHUP if the process is
        # the session leader: we installed a SIGHUP signal handler
        # to ignore this signal.
        self.addCleanup(os.close, master_fd)
        self.addCleanup(os.close, slave_fd)

        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_dim:
            self.assertEqual(tty.tcgetwinsize(slave_fd), new_dim,
                             "openpty() failed to set slave window size")

        # 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")
        write_all(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")
        write_all(slave_fd, TEST_STRING_2[:5])
        write_all(slave_fd, TEST_STRING_2[5:])
        s2 = _readline(master_fd)
        self.assertEqual(b'For my pet fish, Eric.\n', normalize_output(s2))

    def test_fork(self):
        debug("calling pty.fork()")
        pid, master_fd = pty.fork()
        self.addCleanup(os.close, master_fd)
        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")

    def test_master_read(self):
        # XXX(nnorwitz):  this test leaks fds when there is an error.
        debug("Calling pty.openpty()")
        master_fd, slave_fd = pty.openpty()
        debug(f"Got master_fd '{master_fd}', slave_fd '{slave_fd}'")

        self.addCleanup(os.close, master_fd)

        debug("Closing slave_fd")
        os.close(slave_fd)

        debug("Reading from master_fd")
        try:
            data = os.read(master_fd, 1)
        except OSError: # Linux
            data = b""

        self.assertEqual(data, b"")

    def test_spawn_doesnt_hang(self):
        self.addCleanup(unlink, TESTFN)
        with open(TESTFN, 'wb') as f:
            STDOUT_FILENO = 1
            dup_stdout = os.dup(STDOUT_FILENO)
            os.dup2(f.fileno(), STDOUT_FILENO)
            buf = b''
            def master_read(fd):
                nonlocal buf
                data = os.read(fd, 1024)
                buf += data
                return data
            try:
                pty.spawn([sys.executable, '-c', 'print("hi there")'],
                          master_read)
            finally:
                os.dup2(dup_stdout, STDOUT_FILENO)
                os.close(dup_stdout)
        self.assertEqual(buf, b'hi there\r\n')
        with open(TESTFN, 'rb') as f:
            self.assertEqual(f.read(), b'hi there\r\n')

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_close = pty.close
        self.orig_pty__copy = pty._copy
        self.orig_pty_fork = pty.fork
        self.orig_pty_select = pty.select
        self.orig_pty_setraw = pty.setraw
        self.orig_pty_tcgetattr = pty.tcgetattr
        self.orig_pty_tcsetattr = pty.tcsetattr
        self.orig_pty_waitpid = pty.waitpid
        self.fds = []  # A list of file descriptors to close.
        self.files = []
        self.select_input = []
        self.select_output = []
        self.tcsetattr_mode_setting = None

    def tearDown(self):
        pty.STDIN_FILENO = self.orig_stdin_fileno
        pty.STDOUT_FILENO = self.orig_stdout_fileno
        pty.close = self.orig_pty_close
        pty._copy = self.orig_pty__copy
        pty.fork = self.orig_pty_fork
        pty.select = self.orig_pty_select
        pty.setraw = self.orig_pty_setraw
        pty.tcgetattr = self.orig_pty_tcgetattr
        pty.tcsetattr = self.orig_pty_tcsetattr
        pty.waitpid = self.orig_pty_waitpid
        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):
        # This will raise IndexError when no more expected calls exist.
        self.assertEqual((rfds, wfds, xfds), self.select_input.pop(0))
        return self.select_output.pop(0)

    def _make_mock_fork(self, pid):
        def mock_fork():
            return (pid, 12)
        return mock_fork

    def _mock_tcsetattr(self, fileno, opt, mode):
        self.tcsetattr_mode_setting = mode

    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.
        write_all(masters[1], b'from master')
        write_all(write_to_stdin_fd, b'from stdin')

        # Expect three select calls, the last one will cause IndexError
        pty.select = self._mock_select
        self.select_input.append(([mock_stdin_fd, masters[0]], [], []))
        self.select_output.append(([mock_stdin_fd, masters[0]], [], []))
        self.select_input.append(([mock_stdin_fd, masters[0]], [mock_stdout_fd, masters[0]], []))
        self.select_output.append(([], [mock_stdout_fd, masters[0]], []))
        self.select_input.append(([mock_stdin_fd, masters[0]], [], []))

        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__restore_tty_mode_normal_return(self):
        """Test that spawn resets the tty mode no when _copy returns normally."""

        # PID 1 is returned from mocked fork to run the parent branch
        # of code
        pty.fork = self._make_mock_fork(1)

        status_sentinel = object()
        pty.waitpid = lambda _1, _2: [None, status_sentinel]
        pty.close = lambda _: None

        pty._copy = lambda _1, _2, _3: None

        mode_sentinel = object()
        pty.tcgetattr = lambda fd: mode_sentinel
        pty.tcsetattr = self._mock_tcsetattr
        pty.setraw = lambda _: None

        self.assertEqual(pty.spawn([]), status_sentinel, "pty.waitpid process status not returned by pty.spawn")
        self.assertEqual(self.tcsetattr_mode_setting, mode_sentinel, "pty.tcsetattr not called with original mode value")


def tearDownModule():
    reap_children()


if __name__ == "__main__":
    unittest.main()