Repository navigation
Expand file tree
/
Copy pathunix_events.py
More file actions
1487 lines (1233 loc) · 51.2 KB
/
Copy pathunix_events.py
File metadata and controls
1487 lines (1233 loc) · 51.2 KB
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
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
"""Selector event loop for Unix with signal handling."""
import errno
import io
import itertools
import os
import selectors
import signal
import socket
import stat
import subprocess
import sys
import threading
import warnings
from . import base_events
from . import base_subprocess
from . import constants
from . import coroutines
from . import events
from . import exceptions
from . import futures
from . import selector_events
from . import tasks
from . import transports
from .log import logger
__all__ = (
'SelectorEventLoop',
'AbstractChildWatcher', 'SafeChildWatcher',
'FastChildWatcher', 'PidfdChildWatcher',
'MultiLoopChildWatcher', 'ThreadedChildWatcher',
'DefaultEventLoopPolicy',
)
if sys.platform == 'win32': # pragma: no cover
raise ImportError('Signals are not really supported on Windows')
def _sighandler_noop(signum, frame):
"""Dummy signal handler."""
pass
class _UnixSelectorEventLoop(selector_events.BaseSelectorEventLoop):
"""Unix event loop.
Adds signal handling and UNIX Domain Socket support to SelectorEventLoop.
"""
def __init__(self, selector=None):
super().__init__(selector)
self._signal_handlers = {}
def close(self):
super().close()
if not sys.is_finalizing():
for sig in list(self._signal_handlers):
self.remove_signal_handler(sig)
else:
if self._signal_handlers:
warnings.warn(f"Closing the loop {self!r} "
f"on interpreter shutdown "
f"stage, skipping signal handlers removal",
ResourceWarning,
source=self)
self._signal_handlers.clear()
def _process_self_data(self, data):
for signum in data:
if not signum:
# ignore null bytes written by _write_to_self()
continue
self._handle_signal(signum)
def add_signal_handler(self, sig, callback, *args):
"""Add a handler for a signal. UNIX only.
This method can only be called from the main thread.
Raise ValueError if the signal number is invalid or uncatchable.
Raise RuntimeError if there is a problem setting up the handler.
"""
if (coroutines.iscoroutine(callback) or
coroutines.iscoroutinefunction(callback)):
raise TypeError("coroutines cannot be used "
"with add_signal_handler()")
self._check_signal(sig)
self._check_closed()
try:
# set_wakeup_fd() raises ValueError if this is not the
# main thread. By calling it early we ensure that an
# event loop running in another thread cannot add a signal
# handler.
signal.set_wakeup_fd(self._csock.fileno())
except (ValueError, OSError) as exc:
raise RuntimeError(str(exc))
handle = events.Handle(callback, args, self, None)
self._signal_handlers[sig] = handle
try:
# Register a dummy signal handler to ask Python to write the signal
# number in the wakup file descriptor. _process_self_data() will
# read signal numbers from this file descriptor to handle signals.
signal.signal(sig, _sighandler_noop)
# Set SA_RESTART to limit EINTR occurrences.
signal.siginterrupt(sig, False)
except OSError as exc:
del self._signal_handlers[sig]
if not self._signal_handlers:
try:
signal.set_wakeup_fd(-1)
except (ValueError, OSError) as nexc:
logger.info('set_wakeup_fd(-1) failed: %s', nexc)
if exc.errno == errno.EINVAL:
raise RuntimeError(f'sig {sig} cannot be caught')
else:
raise
def _handle_signal(self, sig):
"""Internal helper that is the actual signal handler."""
handle = self._signal_handlers.get(sig)
if handle is None:
return # Assume it's some race condition.
if handle._cancelled:
self.remove_signal_handler(sig) # Remove it properly.
else:
self._add_callback_signalsafe(handle)
def remove_signal_handler(self, sig):
"""Remove a handler for a signal. UNIX only.
Return True if a signal handler was removed, False if not.
"""
self._check_signal(sig)
try:
del self._signal_handlers[sig]
except KeyError:
return False
if sig == signal.SIGINT:
handler = signal.default_int_handler
else:
handler = signal.SIG_DFL
try:
signal.signal(sig, handler)
except OSError as exc:
if exc.errno == errno.EINVAL:
raise RuntimeError(f'sig {sig} cannot be caught')
else:
raise
if not self._signal_handlers:
try:
signal.set_wakeup_fd(-1)
except (ValueError, OSError) as exc:
logger.info('set_wakeup_fd(-1) failed: %s', exc)
return True
def _check_signal(self, sig):
"""Internal helper to validate a signal.
Raise ValueError if the signal number is invalid or uncatchable.
Raise RuntimeError if there is a problem setting up the handler.
"""
if not isinstance(sig, int):
raise TypeError(f'sig must be an int, not {sig!r}')
if sig not in signal.valid_signals():
raise ValueError(f'invalid signal number {sig}')
def _make_read_pipe_transport(self, pipe, protocol, waiter=None,
extra=None):
return _UnixReadPipeTransport(self, pipe, protocol, waiter, extra)
def _make_write_pipe_transport(self, pipe, protocol, waiter=None,
extra=None):
return _UnixWritePipeTransport(self, pipe, protocol, waiter, extra)
async def _make_subprocess_transport(self, protocol, args, shell,
stdin, stdout, stderr, bufsize,
extra=None, **kwargs):
with events.get_child_watcher() as watcher:
if not watcher.is_active():
# Check early.
# Raising exception before process creation
# prevents subprocess execution if the watcher
# is not ready to handle it.
raise RuntimeError("asyncio.get_child_watcher() is not activated, "
"subprocess support is not installed.")
waiter = self.create_future()
transp = _UnixSubprocessTransport(self, protocol, args, shell,
stdin, stdout, stderr, bufsize,
waiter=waiter, extra=extra,
**kwargs)
watcher.add_child_handler(transp.get_pid(),
self._child_watcher_callback, transp)
try:
await waiter
except (SystemExit, KeyboardInterrupt):
raise
except BaseException:
transp.close()
await transp._wait()
raise
return transp
def _child_watcher_callback(self, pid, returncode, transp):
self.call_soon_threadsafe(transp._process_exited, returncode)
async def create_unix_connection(
self, protocol_factory, path=None, *,
ssl=None, sock=None,
server_hostname=None,
ssl_handshake_timeout=None):
assert server_hostname is None or isinstance(server_hostname, str)
if ssl:
if server_hostname is None:
raise ValueError(
'you have to pass server_hostname when using ssl')
else:
if server_hostname is not None:
raise ValueError('server_hostname is only meaningful with ssl')
if ssl_handshake_timeout is not None:
raise ValueError(
'ssl_handshake_timeout is only meaningful with ssl')
if path is not None:
if sock is not None:
raise ValueError(
'path and sock can not be specified at the same time')
path = os.fspath(path)
sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM, 0)
try:
sock.setblocking(False)
await self.sock_connect(sock, path)
except:
sock.close()
raise
else:
if sock is None:
raise ValueError('no path and sock were specified')
if (sock.family != socket.AF_UNIX or
sock.type != socket.SOCK_STREAM):
raise ValueError(
f'A UNIX Domain Stream Socket was expected, got {sock!r}')
sock.setblocking(False)
transport, protocol = await self._create_connection_transport(
sock, protocol_factory, ssl, server_hostname,
ssl_handshake_timeout=ssl_handshake_timeout)
return transport, protocol
async def create_unix_server(
self, protocol_factory, path=None, *,
sock=None, backlog=100, ssl=None,
ssl_handshake_timeout=None,
start_serving=True):
if isinstance(ssl, bool):
raise TypeError('ssl argument must be an SSLContext or None')
if ssl_handshake_timeout is not None and not ssl:
raise ValueError(
'ssl_handshake_timeout is only meaningful with ssl')
if path is not None:
if sock is not None:
raise ValueError(
'path and sock can not be specified at the same time')
path = os.fspath(path)
sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
# Check for abstract socket. `str` and `bytes` paths are supported.
if path[0] not in (0, '\x00'):
try:
if stat.S_ISSOCK(os.stat(path).st_mode):
os.remove(path)
except FileNotFoundError:
pass
except OSError as err:
# Directory may have permissions only to create socket.
logger.error('Unable to check or remove stale UNIX socket '
'%r: %r', path, err)
try:
sock.bind(path)
except OSError as exc:
sock.close()
if exc.errno == errno.EADDRINUSE:
# Let's improve the error message by adding
# with what exact address it occurs.
msg = f'Address {path!r} is already in use'
raise OSError(errno.EADDRINUSE, msg) from None
else:
raise
except:
sock.close()
raise
else:
if sock is None:
raise ValueError(
'path was not specified, and no sock specified')
if (sock.family != socket.AF_UNIX or
sock.type != socket.SOCK_STREAM):
raise ValueError(
f'A UNIX Domain Stream Socket was expected, got {sock!r}')
sock.setblocking(False)
server = base_events.Server(self, [sock], protocol_factory,
ssl, backlog, ssl_handshake_timeout)
if start_serving:
server._start_serving()
# Skip one loop iteration so that all 'loop.add_reader'
# go through.
await tasks.sleep(0, loop=self)
return server
async def _sock_sendfile_native(self, sock, file, offset, count):
try:
os.sendfile
except AttributeError:
raise exceptions.SendfileNotAvailableError(
"os.sendfile() is not available")
try:
fileno = file.fileno()
except (AttributeError, io.UnsupportedOperation) as err:
raise exceptions.SendfileNotAvailableError("not a regular file")
try:
fsize = os.fstat(fileno).st_size
except OSError:
raise exceptions.SendfileNotAvailableError("not a regular file")
blocksize = count if count else fsize
if not blocksize:
return 0 # empty file
fut = self.create_future()
self._sock_sendfile_native_impl(fut, None, sock, fileno,
offset, count, blocksize, 0)
return await fut
def _sock_sendfile_native_impl(self, fut, registered_fd, sock, fileno,
offset, count, blocksize, total_sent):
fd = sock.fileno()
if registered_fd is not None:
# Remove the callback early. It should be rare that the
# selector says the fd is ready but the call still returns
# EAGAIN, and I am willing to take a hit in that case in
# order to simplify the common case.
self.remove_writer(registered_fd)
if fut.cancelled():
self._sock_sendfile_update_filepos(fileno, offset, total_sent)
return
if count:
blocksize = count - total_sent
if blocksize <= 0:
self._sock_sendfile_update_filepos(fileno, offset, total_sent)
fut.set_result(total_sent)
return
try:
sent = os.sendfile(fd, fileno, offset, blocksize)
except (BlockingIOError, InterruptedError):
if registered_fd is None:
self._sock_add_cancellation_callback(fut, sock)
self.add_writer(fd, self._sock_sendfile_native_impl, fut,
fd, sock, fileno,
offset, count, blocksize, total_sent)
except OSError as exc:
if (registered_fd is not None and
exc.errno == errno.ENOTCONN and
type(exc) is not ConnectionError):
# If we have an ENOTCONN and this isn't a first call to
# sendfile(), i.e. the connection was closed in the middle
# of the operation, normalize the error to ConnectionError
# to make it consistent across all Posix systems.
new_exc = ConnectionError(
"socket is not connected", errno.ENOTCONN)
new_exc.__cause__ = exc
exc = new_exc
if total_sent == 0:
# We can get here for different reasons, the main
# one being 'file' is not a regular mmap(2)-like
# file, in which case we'll fall back on using
# plain send().
err = exceptions.SendfileNotAvailableError(
"os.sendfile call failed")
self._sock_sendfile_update_filepos(fileno, offset, total_sent)
fut.set_exception(err)
else:
self._sock_sendfile_update_filepos(fileno, offset, total_sent)
fut.set_exception(exc)
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as exc:
self._sock_sendfile_update_filepos(fileno, offset, total_sent)
fut.set_exception(exc)
else:
if sent == 0:
# EOF
self._sock_sendfile_update_filepos(fileno, offset, total_sent)
fut.set_result(total_sent)
else:
offset += sent
total_sent += sent
if registered_fd is None:
self._sock_add_cancellation_callback(fut, sock)
self.add_writer(fd, self._sock_sendfile_native_impl, fut,
fd, sock, fileno,
offset, count, blocksize, total_sent)
def _sock_sendfile_update_filepos(self, fileno, offset, total_sent):
if total_sent > 0:
os.lseek(fileno, offset, os.SEEK_SET)
def _sock_add_cancellation_callback(self, fut, sock):
def cb(fut):
if fut.cancelled():
fd = sock.fileno()
if fd != -1:
self.remove_writer(fd)
fut.add_done_callback(cb)
class _UnixReadPipeTransport(transports.ReadTransport):
max_size = 256 * 1024 # max bytes we read in one event loop iteration
def __init__(self, loop, pipe, protocol, waiter=None, extra=None):
super().__init__(extra)
self._extra['pipe'] = pipe
self._loop = loop
self._pipe = pipe
self._fileno = pipe.fileno()
self._protocol = protocol
self._closing = False
self._paused = False
mode = os.fstat(self._fileno).st_mode
if not (stat.S_ISFIFO(mode) or
stat.S_ISSOCK(mode) or
stat.S_ISCHR(mode)):
self._pipe = None
self._fileno = None
self._protocol = None
raise ValueError("Pipe transport is for pipes/sockets only.")
os.set_blocking(self._fileno, False)
self._loop.call_soon(self._protocol.connection_made, self)
# only start reading when connection_made() has been called
self._loop.call_soon(self._loop._add_reader,
self._fileno, self._read_ready)
if waiter is not None:
# only wake up the waiter when connection_made() has been called
self._loop.call_soon(futures._set_result_unless_cancelled,
waiter, None)
def __repr__(self):
info = [self.__class__.__name__]
if self._pipe is None:
info.append('closed')
elif self._closing:
info.append('closing')
info.append(f'fd={self._fileno}')
selector = getattr(self._loop, '_selector', None)
if self._pipe is not None and selector is not None:
polling = selector_events._test_selector_event(
selector, self._fileno, selectors.EVENT_READ)
if polling:
info.append('polling')
else:
info.append('idle')
elif self._pipe is not None:
info.append('open')
else:
info.append('closed')
return '<{}>'.format(' '.join(info))
def _read_ready(self):
try:
data = os.read(self._fileno, self.max_size)
except (BlockingIOError, InterruptedError):
pass
except OSError as exc:
self._fatal_error(exc, 'Fatal read error on pipe transport')
else:
if data:
self._protocol.data_received(data)
else:
if self._loop.get_debug():
logger.info("%r was closed by peer", self)
self._closing = True
self._loop._remove_reader(self._fileno)
self._loop.call_soon(self._protocol.eof_received)
self._loop.call_soon(self._call_connection_lost, None)
def pause_reading(self):
if self._closing or self._paused:
return
self._paused = True
self._loop._remove_reader(self._fileno)
if self._loop.get_debug():
logger.debug("%r pauses reading", self)
def resume_reading(self):
if self._closing or not self._paused:
return
self._paused = False
self._loop._add_reader(self._fileno, self._read_ready)
if self._loop.get_debug():
logger.debug("%r resumes reading", self)
def set_protocol(self, protocol):
self._protocol = protocol
def get_protocol(self):
return self._protocol
def is_closing(self):
return self._closing
def close(self):
if not self._closing:
self._close(None)
def __del__(self, _warn=warnings.warn):
if self._pipe is not None:
_warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
self._pipe.close()
def _fatal_error(self, exc, message='Fatal error on pipe transport'):
# should be called by exception handler only
if (isinstance(exc, OSError) and exc.errno == errno.EIO):
if self._loop.get_debug():
logger.debug("%r: %s", self, message, exc_info=True)
else:
self._loop.call_exception_handler({
'message': message,
'exception': exc,
'transport': self,
'protocol': self._protocol,
})
self._close(exc)
def _close(self, exc):
self._closing = True
self._loop._remove_reader(self._fileno)
self._loop.call_soon(self._call_connection_lost, exc)
def _call_connection_lost(self, exc):
try:
self._protocol.connection_lost(exc)
finally:
self._pipe.close()
self._pipe = None
self._protocol = None
self._loop = None
class _UnixWritePipeTransport(transports._FlowControlMixin,
transports.WriteTransport):
def __init__(self, loop, pipe, protocol, waiter=None, extra=None):
super().__init__(extra, loop)
self._extra['pipe'] = pipe
self._pipe = pipe
self._fileno = pipe.fileno()
self._protocol = protocol
self._buffer = bytearray()
self._conn_lost = 0
self._closing = False # Set when close() or write_eof() called.
mode = os.fstat(self._fileno).st_mode
is_char = stat.S_ISCHR(mode)
is_fifo = stat.S_ISFIFO(mode)
is_socket = stat.S_ISSOCK(mode)
if not (is_char or is_fifo or is_socket):
self._pipe = None
self._fileno = None
self._protocol = None
raise ValueError("Pipe transport is only for "
"pipes, sockets and character devices")
os.set_blocking(self._fileno, False)
self._loop.call_soon(self._protocol.connection_made, self)
# On AIX, the reader trick (to be notified when the read end of the
# socket is closed) only works for sockets. On other platforms it
# works for pipes and sockets. (Exception: OS X 10.4? Issue #19294.)
if is_socket or (is_fifo and not sys.platform.startswith("aix")):
# only start reading when connection_made() has been called
self._loop.call_soon(self._loop._add_reader,
self._fileno, self._read_ready)
if waiter is not None:
# only wake up the waiter when connection_made() has been called
self._loop.call_soon(futures._set_result_unless_cancelled,
waiter, None)
def __repr__(self):
info = [self.__class__.__name__]
if self._pipe is None:
info.append('closed')
elif self._closing:
info.append('closing')
info.append(f'fd={self._fileno}')
selector = getattr(self._loop, '_selector', None)
if self._pipe is not None and selector is not None:
polling = selector_events._test_selector_event(
selector, self._fileno, selectors.EVENT_WRITE)
if polling:
info.append('polling')
else:
info.append('idle')
bufsize = self.get_write_buffer_size()
info.append(f'bufsize={bufsize}')
elif self._pipe is not None:
info.append('open')
else:
info.append('closed')
return '<{}>'.format(' '.join(info))
def get_write_buffer_size(self):
return len(self._buffer)
def _read_ready(self):
# Pipe was closed by peer.
if self._loop.get_debug():
logger.info("%r was closed by peer", self)
if self._buffer:
self._close(BrokenPipeError())
else:
self._close()
def write(self, data):
assert isinstance(data, (bytes, bytearray, memoryview)), repr(data)
if isinstance(data, bytearray):
data = memoryview(data)
if not data:
return
if self._conn_lost or self._closing:
if self._conn_lost >= constants.LOG_THRESHOLD_FOR_CONNLOST_WRITES:
logger.warning('pipe closed by peer or '
'os.write(pipe, data) raised exception.')
self._conn_lost += 1
return
if not self._buffer:
# Attempt to send it right away first.
try:
n = os.write(self._fileno, data)
except (BlockingIOError, InterruptedError):
n = 0
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as exc:
self._conn_lost += 1
self._fatal_error(exc, 'Fatal write error on pipe transport')
return
if n == len(data):
return
elif n > 0:
data = memoryview(data)[n:]
self._loop._add_writer(self._fileno, self._write_ready)
self._buffer += data
self._maybe_pause_protocol()
def _write_ready(self):
assert self._buffer, 'Data should not be empty'
try:
n = os.write(self._fileno, self._buffer)
except (BlockingIOError, InterruptedError):
pass
except (SystemExit, KeyboardInterrupt):
raise
except BaseException as exc:
self._buffer.clear()
self._conn_lost += 1
# Remove writer here, _fatal_error() doesn't it
# because _buffer is empty.
self._loop._remove_writer(self._fileno)
self._fatal_error(exc, 'Fatal write error on pipe transport')
else:
if n == len(self._buffer):
self._buffer.clear()
self._loop._remove_writer(self._fileno)
self._maybe_resume_protocol() # May append to buffer.
if self._closing:
self._loop._remove_reader(self._fileno)
self._call_connection_lost(None)
return
elif n > 0:
del self._buffer[:n]
def can_write_eof(self):
return True
def write_eof(self):
if self._closing:
return
assert self._pipe
self._closing = True
if not self._buffer:
self._loop._remove_reader(self._fileno)
self._loop.call_soon(self._call_connection_lost, None)
def set_protocol(self, protocol):
self._protocol = protocol
def get_protocol(self):
return self._protocol
def is_closing(self):
return self._closing
def close(self):
if self._pipe is not None and not self._closing:
# write_eof is all what we needed to close the write pipe
self.write_eof()
def __del__(self, _warn=warnings.warn):
if self._pipe is not None:
_warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
self._pipe.close()
def abort(self):
self._close(None)
def _fatal_error(self, exc, message='Fatal error on pipe transport'):
# should be called by exception handler only
if isinstance(exc, OSError):
if self._loop.get_debug():
logger.debug("%r: %s", self, message, exc_info=True)
else:
self._loop.call_exception_handler({
'message': message,
'exception': exc,
'transport': self,
'protocol': self._protocol,
})
self._close(exc)
def _close(self, exc=None):
self._closing = True
if self._buffer:
self._loop._remove_writer(self._fileno)
self._buffer.clear()
self._loop._remove_reader(self._fileno)
self._loop.call_soon(self._call_connection_lost, exc)
def _call_connection_lost(self, exc):
try:
self._protocol.connection_lost(exc)
finally:
self._pipe.close()
self._pipe = None
self._protocol = None
self._loop = None
class _UnixSubprocessTransport(base_subprocess.BaseSubprocessTransport):
def _start(self, args, shell, stdin, stdout, stderr, bufsize, **kwargs):
stdin_w = None
if stdin == subprocess.PIPE:
# Use a socket pair for stdin, since not all platforms
# support selecting read events on the write end of a
# socket (which we use in order to detect closing of the
# other end). Notably this is needed on AIX, and works
# just fine on other platforms.
stdin, stdin_w = socket.socketpair()
try:
self._proc = subprocess.Popen(
args, shell=shell, stdin=stdin, stdout=stdout, stderr=stderr,
universal_newlines=False, bufsize=bufsize, **kwargs)
if stdin_w is not None:
stdin.close()
self._proc.stdin = open(stdin_w.detach(), 'wb', buffering=bufsize)
stdin_w = None
finally:
if stdin_w is not None:
stdin.close()
stdin_w.close()
class AbstractChildWatcher:
"""Abstract base class for monitoring child processes.
Objects derived from this class monitor a collection of subprocesses and
report their termination or interruption by a signal.
New callbacks are registered with .add_child_handler(). Starting a new
process must be done within a 'with' block to allow the watcher to suspend
its activity until the new process if fully registered (this is needed to
prevent a race condition in some implementations).
Example:
with watcher:
proc = subprocess.Popen("sleep 1")
watcher.add_child_handler(proc.pid, callback)
Notes:
Implementations of this class must be thread-safe.
Since child watcher objects may catch the SIGCHLD signal and call
waitpid(-1), there should be only one active object per process.
"""
def add_child_handler(self, pid, callback, *args):
"""Register a new child handler.
Arrange for callback(pid, returncode, *args) to be called when
process 'pid' terminates. Specifying another callback for the same
process replaces the previous handler.
Note: callback() must be thread-safe.
"""
raise NotImplementedError()
def remove_child_handler(self, pid):
"""Removes the handler for process 'pid'.
The function returns True if the handler was successfully removed,
False if there was nothing to remove."""
raise NotImplementedError()
def attach_loop(self, loop):
"""Attach the watcher to an event loop.
If the watcher was previously attached to an event loop, then it is
first detached before attaching to the new loop.
Note: loop may be None.
"""
raise NotImplementedError()
def close(self):
"""Close the watcher.
This must be called to make sure that any underlying resource is freed.
"""
raise NotImplementedError()
def is_active(self):
"""Return ``True`` if the watcher is active and is used by the event loop.
Return True if the watcher is installed and ready to handle process exit
notifications.
"""
raise NotImplementedError()
def __enter__(self):
"""Enter the watcher's context and allow starting new processes
This function must return self"""
raise NotImplementedError()
def __exit__(self, a, b, c):
"""Exit the watcher's context"""
raise NotImplementedError()
class PidfdChildWatcher(AbstractChildWatcher):
"""Child watcher implementation using Linux's pid file descriptors.
This child watcher polls process file descriptors (pidfds) to await child
process termination. In some respects, PidfdChildWatcher is a "Goldilocks"
child watcher implementation. It doesn't require signals or threads, doesn't
interfere with any processes launched outside the event loop, and scales
linearly with the number of subprocesses launched by the event loop. The
main disadvantage is that pidfds are specific to Linux, and only work on
recent (5.3+) kernels.
"""
def __init__(self):
self._loop = None
self._callbacks = {}
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, exc_traceback):
pass
def is_active(self):
return self._loop is not None and self._loop.is_running()
def close(self):
self.attach_loop(None)
def attach_loop(self, loop):
if self._loop is not None and loop is None and self._callbacks:
warnings.warn(
'A loop is being detached '
'from a child watcher with pending handlers',
RuntimeWarning)
for pidfd, _, _ in self._callbacks.values():
self._loop._remove_reader(pidfd)
os.close(pidfd)
self._callbacks.clear()
self._loop = loop
def add_child_handler(self, pid, callback, *args):
existing = self._callbacks.get(pid)
if existing is not None:
self._callbacks[pid] = existing[0], callback, args
else:
pidfd = os.pidfd_open(pid)
self._loop._add_reader(pidfd, self._do_wait, pid)
self._callbacks[pid] = pidfd, callback, args
def _do_wait(self, pid):
pidfd, callback, args = self._callbacks.pop(pid)
self._loop._remove_reader(pidfd)
try:
_, status = os.waitpid(pid, 0)
except ChildProcessError:
# The child process is already reaped
# (may happen if waitpid() is called elsewhere).
returncode = 255
logger.warning(
"child process pid %d exit status already read: "
" will report returncode 255",
pid)
else:
returncode = _compute_returncode(status)
os.close(pidfd)
callback(pid, returncode, *args)
def remove_child_handler(self, pid):
try:
pidfd, _, _ = self._callbacks.pop(pid)
except KeyError:
return False
self._loop._remove_reader(pidfd)
os.close(pidfd)
return True
def _compute_returncode(status):
if os.WIFSIGNALED(status):
# The child process died because of a signal.
return -os.WTERMSIG(status)
elif os.WIFEXITED(status):
# The child process exited (e.g sys.exit()).
return os.WEXITSTATUS(status)
else:
# The child exited, but we don't understand its status.
# This shouldn't happen, but if it does, let's just
# return that status; perhaps that helps debug it.
return status
class BaseChildWatcher(AbstractChildWatcher):
def __init__(self):
self._loop = None
self._callbacks = {}
def close(self):
self.attach_loop(None)
def is_active(self):
return self._loop is not None and self._loop.is_running()
def _do_waitpid(self, expected_pid):
raise NotImplementedError()
def _do_waitpid_all(self):
raise NotImplementedError()
def attach_loop(self, loop):
assert loop is None or isinstance(loop, events.AbstractEventLoop)
if self._loop is not None and loop is None and self._callbacks:
warnings.warn(
'A loop is being detached '
'from a child watcher with pending handlers',
RuntimeWarning)