Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 1 | """Selector event loop for Unix with signal handling.""" |
| 2 | |
| 3 | import errno |
| 4 | import io |
| 5 | import itertools |
| 6 | import os |
| 7 | import selectors |
| 8 | import signal |
| 9 | import socket |
| 10 | import stat |
| 11 | import subprocess |
| 12 | import sys |
| 13 | import threading |
| 14 | import warnings |
| 15 | |
| 16 | from . import base_events |
| 17 | from . import base_subprocess |
| 18 | from . import constants |
| 19 | from . import coroutines |
| 20 | from . import events |
| 21 | from . import exceptions |
| 22 | from . import futures |
| 23 | from . import selector_events |
| 24 | from . import tasks |
| 25 | from . import transports |
| 26 | from .log import logger |
| 27 | |
| 28 | |
| 29 | __all__ = ( |
| 30 | 'SelectorEventLoop', |
| 31 | 'AbstractChildWatcher', 'SafeChildWatcher', |
Elliott Hughes | 96c2b6b | 2021-01-26 11:15:15 -0800 | [diff] [blame] | 32 | 'FastChildWatcher', 'PidfdChildWatcher', |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 33 | 'MultiLoopChildWatcher', 'ThreadedChildWatcher', |
| 34 | 'DefaultEventLoopPolicy', |
| 35 | ) |
| 36 | |
| 37 | |
| 38 | if sys.platform == 'win32': # pragma: no cover |
| 39 | raise ImportError('Signals are not really supported on Windows') |
| 40 | |
| 41 | |
| 42 | def _sighandler_noop(signum, frame): |
| 43 | """Dummy signal handler.""" |
| 44 | pass |
| 45 | |
| 46 | |
Dan Willemsen | c9fa001 | 2022-03-25 22:58:53 +0000 | [diff] [blame^] | 47 | def waitstatus_to_exitcode(status): |
| 48 | try: |
| 49 | return os.waitstatus_to_exitcode(status) |
| 50 | except ValueError: |
| 51 | # The child exited, but we don't understand its status. |
| 52 | # This shouldn't happen, but if it does, let's just |
| 53 | # return that status; perhaps that helps debug it. |
| 54 | return status |
| 55 | |
| 56 | |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 57 | class _UnixSelectorEventLoop(selector_events.BaseSelectorEventLoop): |
| 58 | """Unix event loop. |
| 59 | |
| 60 | Adds signal handling and UNIX Domain Socket support to SelectorEventLoop. |
| 61 | """ |
| 62 | |
| 63 | def __init__(self, selector=None): |
| 64 | super().__init__(selector) |
| 65 | self._signal_handlers = {} |
| 66 | |
| 67 | def close(self): |
| 68 | super().close() |
| 69 | if not sys.is_finalizing(): |
| 70 | for sig in list(self._signal_handlers): |
| 71 | self.remove_signal_handler(sig) |
| 72 | else: |
| 73 | if self._signal_handlers: |
| 74 | warnings.warn(f"Closing the loop {self!r} " |
| 75 | f"on interpreter shutdown " |
| 76 | f"stage, skipping signal handlers removal", |
| 77 | ResourceWarning, |
| 78 | source=self) |
| 79 | self._signal_handlers.clear() |
| 80 | |
| 81 | def _process_self_data(self, data): |
| 82 | for signum in data: |
| 83 | if not signum: |
| 84 | # ignore null bytes written by _write_to_self() |
| 85 | continue |
| 86 | self._handle_signal(signum) |
| 87 | |
| 88 | def add_signal_handler(self, sig, callback, *args): |
| 89 | """Add a handler for a signal. UNIX only. |
| 90 | |
| 91 | Raise ValueError if the signal number is invalid or uncatchable. |
| 92 | Raise RuntimeError if there is a problem setting up the handler. |
| 93 | """ |
| 94 | if (coroutines.iscoroutine(callback) or |
| 95 | coroutines.iscoroutinefunction(callback)): |
| 96 | raise TypeError("coroutines cannot be used " |
| 97 | "with add_signal_handler()") |
| 98 | self._check_signal(sig) |
| 99 | self._check_closed() |
| 100 | try: |
| 101 | # set_wakeup_fd() raises ValueError if this is not the |
| 102 | # main thread. By calling it early we ensure that an |
| 103 | # event loop running in another thread cannot add a signal |
| 104 | # handler. |
| 105 | signal.set_wakeup_fd(self._csock.fileno()) |
| 106 | except (ValueError, OSError) as exc: |
| 107 | raise RuntimeError(str(exc)) |
| 108 | |
| 109 | handle = events.Handle(callback, args, self, None) |
| 110 | self._signal_handlers[sig] = handle |
| 111 | |
| 112 | try: |
| 113 | # Register a dummy signal handler to ask Python to write the signal |
| 114 | # number in the wakeup file descriptor. _process_self_data() will |
| 115 | # read signal numbers from this file descriptor to handle signals. |
| 116 | signal.signal(sig, _sighandler_noop) |
| 117 | |
| 118 | # Set SA_RESTART to limit EINTR occurrences. |
| 119 | signal.siginterrupt(sig, False) |
| 120 | except OSError as exc: |
| 121 | del self._signal_handlers[sig] |
| 122 | if not self._signal_handlers: |
| 123 | try: |
| 124 | signal.set_wakeup_fd(-1) |
| 125 | except (ValueError, OSError) as nexc: |
| 126 | logger.info('set_wakeup_fd(-1) failed: %s', nexc) |
| 127 | |
| 128 | if exc.errno == errno.EINVAL: |
| 129 | raise RuntimeError(f'sig {sig} cannot be caught') |
| 130 | else: |
| 131 | raise |
| 132 | |
| 133 | def _handle_signal(self, sig): |
| 134 | """Internal helper that is the actual signal handler.""" |
| 135 | handle = self._signal_handlers.get(sig) |
| 136 | if handle is None: |
| 137 | return # Assume it's some race condition. |
| 138 | if handle._cancelled: |
| 139 | self.remove_signal_handler(sig) # Remove it properly. |
| 140 | else: |
| 141 | self._add_callback_signalsafe(handle) |
| 142 | |
| 143 | def remove_signal_handler(self, sig): |
| 144 | """Remove a handler for a signal. UNIX only. |
| 145 | |
| 146 | Return True if a signal handler was removed, False if not. |
| 147 | """ |
| 148 | self._check_signal(sig) |
| 149 | try: |
| 150 | del self._signal_handlers[sig] |
| 151 | except KeyError: |
| 152 | return False |
| 153 | |
| 154 | if sig == signal.SIGINT: |
| 155 | handler = signal.default_int_handler |
| 156 | else: |
| 157 | handler = signal.SIG_DFL |
| 158 | |
| 159 | try: |
| 160 | signal.signal(sig, handler) |
| 161 | except OSError as exc: |
| 162 | if exc.errno == errno.EINVAL: |
| 163 | raise RuntimeError(f'sig {sig} cannot be caught') |
| 164 | else: |
| 165 | raise |
| 166 | |
| 167 | if not self._signal_handlers: |
| 168 | try: |
| 169 | signal.set_wakeup_fd(-1) |
| 170 | except (ValueError, OSError) as exc: |
| 171 | logger.info('set_wakeup_fd(-1) failed: %s', exc) |
| 172 | |
| 173 | return True |
| 174 | |
| 175 | def _check_signal(self, sig): |
| 176 | """Internal helper to validate a signal. |
| 177 | |
| 178 | Raise ValueError if the signal number is invalid or uncatchable. |
| 179 | Raise RuntimeError if there is a problem setting up the handler. |
| 180 | """ |
| 181 | if not isinstance(sig, int): |
| 182 | raise TypeError(f'sig must be an int, not {sig!r}') |
| 183 | |
| 184 | if sig not in signal.valid_signals(): |
| 185 | raise ValueError(f'invalid signal number {sig}') |
| 186 | |
| 187 | def _make_read_pipe_transport(self, pipe, protocol, waiter=None, |
| 188 | extra=None): |
| 189 | return _UnixReadPipeTransport(self, pipe, protocol, waiter, extra) |
| 190 | |
| 191 | def _make_write_pipe_transport(self, pipe, protocol, waiter=None, |
| 192 | extra=None): |
| 193 | return _UnixWritePipeTransport(self, pipe, protocol, waiter, extra) |
| 194 | |
| 195 | async def _make_subprocess_transport(self, protocol, args, shell, |
| 196 | stdin, stdout, stderr, bufsize, |
| 197 | extra=None, **kwargs): |
| 198 | with events.get_child_watcher() as watcher: |
| 199 | if not watcher.is_active(): |
| 200 | # Check early. |
| 201 | # Raising exception before process creation |
| 202 | # prevents subprocess execution if the watcher |
| 203 | # is not ready to handle it. |
| 204 | raise RuntimeError("asyncio.get_child_watcher() is not activated, " |
| 205 | "subprocess support is not installed.") |
| 206 | waiter = self.create_future() |
| 207 | transp = _UnixSubprocessTransport(self, protocol, args, shell, |
| 208 | stdin, stdout, stderr, bufsize, |
| 209 | waiter=waiter, extra=extra, |
| 210 | **kwargs) |
| 211 | |
| 212 | watcher.add_child_handler(transp.get_pid(), |
| 213 | self._child_watcher_callback, transp) |
| 214 | try: |
| 215 | await waiter |
| 216 | except (SystemExit, KeyboardInterrupt): |
| 217 | raise |
| 218 | except BaseException: |
| 219 | transp.close() |
| 220 | await transp._wait() |
| 221 | raise |
| 222 | |
| 223 | return transp |
| 224 | |
| 225 | def _child_watcher_callback(self, pid, returncode, transp): |
| 226 | self.call_soon_threadsafe(transp._process_exited, returncode) |
| 227 | |
| 228 | async def create_unix_connection( |
| 229 | self, protocol_factory, path=None, *, |
| 230 | ssl=None, sock=None, |
| 231 | server_hostname=None, |
| 232 | ssl_handshake_timeout=None): |
| 233 | assert server_hostname is None or isinstance(server_hostname, str) |
| 234 | if ssl: |
| 235 | if server_hostname is None: |
| 236 | raise ValueError( |
| 237 | 'you have to pass server_hostname when using ssl') |
| 238 | else: |
| 239 | if server_hostname is not None: |
| 240 | raise ValueError('server_hostname is only meaningful with ssl') |
| 241 | if ssl_handshake_timeout is not None: |
| 242 | raise ValueError( |
| 243 | 'ssl_handshake_timeout is only meaningful with ssl') |
| 244 | |
| 245 | if path is not None: |
| 246 | if sock is not None: |
| 247 | raise ValueError( |
| 248 | 'path and sock can not be specified at the same time') |
| 249 | |
| 250 | path = os.fspath(path) |
| 251 | sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM, 0) |
| 252 | try: |
| 253 | sock.setblocking(False) |
| 254 | await self.sock_connect(sock, path) |
| 255 | except: |
| 256 | sock.close() |
| 257 | raise |
| 258 | |
| 259 | else: |
| 260 | if sock is None: |
| 261 | raise ValueError('no path and sock were specified') |
| 262 | if (sock.family != socket.AF_UNIX or |
| 263 | sock.type != socket.SOCK_STREAM): |
| 264 | raise ValueError( |
| 265 | f'A UNIX Domain Stream Socket was expected, got {sock!r}') |
| 266 | sock.setblocking(False) |
| 267 | |
| 268 | transport, protocol = await self._create_connection_transport( |
| 269 | sock, protocol_factory, ssl, server_hostname, |
| 270 | ssl_handshake_timeout=ssl_handshake_timeout) |
| 271 | return transport, protocol |
| 272 | |
| 273 | async def create_unix_server( |
| 274 | self, protocol_factory, path=None, *, |
| 275 | sock=None, backlog=100, ssl=None, |
| 276 | ssl_handshake_timeout=None, |
| 277 | start_serving=True): |
| 278 | if isinstance(ssl, bool): |
| 279 | raise TypeError('ssl argument must be an SSLContext or None') |
| 280 | |
| 281 | if ssl_handshake_timeout is not None and not ssl: |
| 282 | raise ValueError( |
| 283 | 'ssl_handshake_timeout is only meaningful with ssl') |
| 284 | |
| 285 | if path is not None: |
| 286 | if sock is not None: |
| 287 | raise ValueError( |
| 288 | 'path and sock can not be specified at the same time') |
| 289 | |
| 290 | path = os.fspath(path) |
| 291 | sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) |
| 292 | |
| 293 | # Check for abstract socket. `str` and `bytes` paths are supported. |
| 294 | if path[0] not in (0, '\x00'): |
| 295 | try: |
| 296 | if stat.S_ISSOCK(os.stat(path).st_mode): |
| 297 | os.remove(path) |
| 298 | except FileNotFoundError: |
| 299 | pass |
| 300 | except OSError as err: |
| 301 | # Directory may have permissions only to create socket. |
| 302 | logger.error('Unable to check or remove stale UNIX socket ' |
| 303 | '%r: %r', path, err) |
| 304 | |
| 305 | try: |
| 306 | sock.bind(path) |
| 307 | except OSError as exc: |
| 308 | sock.close() |
| 309 | if exc.errno == errno.EADDRINUSE: |
| 310 | # Let's improve the error message by adding |
| 311 | # with what exact address it occurs. |
| 312 | msg = f'Address {path!r} is already in use' |
| 313 | raise OSError(errno.EADDRINUSE, msg) from None |
| 314 | else: |
| 315 | raise |
| 316 | except: |
| 317 | sock.close() |
| 318 | raise |
| 319 | else: |
| 320 | if sock is None: |
| 321 | raise ValueError( |
| 322 | 'path was not specified, and no sock specified') |
| 323 | |
| 324 | if (sock.family != socket.AF_UNIX or |
| 325 | sock.type != socket.SOCK_STREAM): |
| 326 | raise ValueError( |
| 327 | f'A UNIX Domain Stream Socket was expected, got {sock!r}') |
| 328 | |
| 329 | sock.setblocking(False) |
| 330 | server = base_events.Server(self, [sock], protocol_factory, |
| 331 | ssl, backlog, ssl_handshake_timeout) |
| 332 | if start_serving: |
| 333 | server._start_serving() |
| 334 | # Skip one loop iteration so that all 'loop.add_reader' |
| 335 | # go through. |
Dan Willemsen | c9fa001 | 2022-03-25 22:58:53 +0000 | [diff] [blame^] | 336 | await tasks.sleep(0) |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 337 | |
| 338 | return server |
| 339 | |
| 340 | async def _sock_sendfile_native(self, sock, file, offset, count): |
| 341 | try: |
| 342 | os.sendfile |
Elliott Hughes | 96c2b6b | 2021-01-26 11:15:15 -0800 | [diff] [blame] | 343 | except AttributeError: |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 344 | raise exceptions.SendfileNotAvailableError( |
| 345 | "os.sendfile() is not available") |
| 346 | try: |
| 347 | fileno = file.fileno() |
| 348 | except (AttributeError, io.UnsupportedOperation) as err: |
| 349 | raise exceptions.SendfileNotAvailableError("not a regular file") |
| 350 | try: |
| 351 | fsize = os.fstat(fileno).st_size |
Elliott Hughes | 96c2b6b | 2021-01-26 11:15:15 -0800 | [diff] [blame] | 352 | except OSError: |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 353 | raise exceptions.SendfileNotAvailableError("not a regular file") |
| 354 | blocksize = count if count else fsize |
| 355 | if not blocksize: |
| 356 | return 0 # empty file |
| 357 | |
| 358 | fut = self.create_future() |
| 359 | self._sock_sendfile_native_impl(fut, None, sock, fileno, |
| 360 | offset, count, blocksize, 0) |
| 361 | return await fut |
| 362 | |
| 363 | def _sock_sendfile_native_impl(self, fut, registered_fd, sock, fileno, |
| 364 | offset, count, blocksize, total_sent): |
| 365 | fd = sock.fileno() |
| 366 | if registered_fd is not None: |
| 367 | # Remove the callback early. It should be rare that the |
| 368 | # selector says the fd is ready but the call still returns |
| 369 | # EAGAIN, and I am willing to take a hit in that case in |
| 370 | # order to simplify the common case. |
| 371 | self.remove_writer(registered_fd) |
| 372 | if fut.cancelled(): |
| 373 | self._sock_sendfile_update_filepos(fileno, offset, total_sent) |
| 374 | return |
| 375 | if count: |
| 376 | blocksize = count - total_sent |
| 377 | if blocksize <= 0: |
| 378 | self._sock_sendfile_update_filepos(fileno, offset, total_sent) |
| 379 | fut.set_result(total_sent) |
| 380 | return |
| 381 | |
| 382 | try: |
| 383 | sent = os.sendfile(fd, fileno, offset, blocksize) |
| 384 | except (BlockingIOError, InterruptedError): |
| 385 | if registered_fd is None: |
| 386 | self._sock_add_cancellation_callback(fut, sock) |
| 387 | self.add_writer(fd, self._sock_sendfile_native_impl, fut, |
| 388 | fd, sock, fileno, |
| 389 | offset, count, blocksize, total_sent) |
| 390 | except OSError as exc: |
| 391 | if (registered_fd is not None and |
| 392 | exc.errno == errno.ENOTCONN and |
| 393 | type(exc) is not ConnectionError): |
| 394 | # If we have an ENOTCONN and this isn't a first call to |
| 395 | # sendfile(), i.e. the connection was closed in the middle |
| 396 | # of the operation, normalize the error to ConnectionError |
| 397 | # to make it consistent across all Posix systems. |
| 398 | new_exc = ConnectionError( |
| 399 | "socket is not connected", errno.ENOTCONN) |
| 400 | new_exc.__cause__ = exc |
| 401 | exc = new_exc |
| 402 | if total_sent == 0: |
| 403 | # We can get here for different reasons, the main |
| 404 | # one being 'file' is not a regular mmap(2)-like |
| 405 | # file, in which case we'll fall back on using |
| 406 | # plain send(). |
| 407 | err = exceptions.SendfileNotAvailableError( |
| 408 | "os.sendfile call failed") |
| 409 | self._sock_sendfile_update_filepos(fileno, offset, total_sent) |
| 410 | fut.set_exception(err) |
| 411 | else: |
| 412 | self._sock_sendfile_update_filepos(fileno, offset, total_sent) |
| 413 | fut.set_exception(exc) |
| 414 | except (SystemExit, KeyboardInterrupt): |
| 415 | raise |
| 416 | except BaseException as exc: |
| 417 | self._sock_sendfile_update_filepos(fileno, offset, total_sent) |
| 418 | fut.set_exception(exc) |
| 419 | else: |
| 420 | if sent == 0: |
| 421 | # EOF |
| 422 | self._sock_sendfile_update_filepos(fileno, offset, total_sent) |
| 423 | fut.set_result(total_sent) |
| 424 | else: |
| 425 | offset += sent |
| 426 | total_sent += sent |
| 427 | if registered_fd is None: |
| 428 | self._sock_add_cancellation_callback(fut, sock) |
| 429 | self.add_writer(fd, self._sock_sendfile_native_impl, fut, |
| 430 | fd, sock, fileno, |
| 431 | offset, count, blocksize, total_sent) |
| 432 | |
| 433 | def _sock_sendfile_update_filepos(self, fileno, offset, total_sent): |
| 434 | if total_sent > 0: |
| 435 | os.lseek(fileno, offset, os.SEEK_SET) |
| 436 | |
| 437 | def _sock_add_cancellation_callback(self, fut, sock): |
| 438 | def cb(fut): |
| 439 | if fut.cancelled(): |
| 440 | fd = sock.fileno() |
| 441 | if fd != -1: |
| 442 | self.remove_writer(fd) |
| 443 | fut.add_done_callback(cb) |
| 444 | |
| 445 | |
| 446 | class _UnixReadPipeTransport(transports.ReadTransport): |
| 447 | |
| 448 | max_size = 256 * 1024 # max bytes we read in one event loop iteration |
| 449 | |
| 450 | def __init__(self, loop, pipe, protocol, waiter=None, extra=None): |
| 451 | super().__init__(extra) |
| 452 | self._extra['pipe'] = pipe |
| 453 | self._loop = loop |
| 454 | self._pipe = pipe |
| 455 | self._fileno = pipe.fileno() |
| 456 | self._protocol = protocol |
| 457 | self._closing = False |
| 458 | self._paused = False |
| 459 | |
| 460 | mode = os.fstat(self._fileno).st_mode |
| 461 | if not (stat.S_ISFIFO(mode) or |
| 462 | stat.S_ISSOCK(mode) or |
| 463 | stat.S_ISCHR(mode)): |
| 464 | self._pipe = None |
| 465 | self._fileno = None |
| 466 | self._protocol = None |
| 467 | raise ValueError("Pipe transport is for pipes/sockets only.") |
| 468 | |
| 469 | os.set_blocking(self._fileno, False) |
| 470 | |
| 471 | self._loop.call_soon(self._protocol.connection_made, self) |
| 472 | # only start reading when connection_made() has been called |
| 473 | self._loop.call_soon(self._loop._add_reader, |
| 474 | self._fileno, self._read_ready) |
| 475 | if waiter is not None: |
| 476 | # only wake up the waiter when connection_made() has been called |
| 477 | self._loop.call_soon(futures._set_result_unless_cancelled, |
| 478 | waiter, None) |
| 479 | |
| 480 | def __repr__(self): |
| 481 | info = [self.__class__.__name__] |
| 482 | if self._pipe is None: |
| 483 | info.append('closed') |
| 484 | elif self._closing: |
| 485 | info.append('closing') |
| 486 | info.append(f'fd={self._fileno}') |
| 487 | selector = getattr(self._loop, '_selector', None) |
| 488 | if self._pipe is not None and selector is not None: |
| 489 | polling = selector_events._test_selector_event( |
| 490 | selector, self._fileno, selectors.EVENT_READ) |
| 491 | if polling: |
| 492 | info.append('polling') |
| 493 | else: |
| 494 | info.append('idle') |
| 495 | elif self._pipe is not None: |
| 496 | info.append('open') |
| 497 | else: |
| 498 | info.append('closed') |
| 499 | return '<{}>'.format(' '.join(info)) |
| 500 | |
| 501 | def _read_ready(self): |
| 502 | try: |
| 503 | data = os.read(self._fileno, self.max_size) |
| 504 | except (BlockingIOError, InterruptedError): |
| 505 | pass |
| 506 | except OSError as exc: |
| 507 | self._fatal_error(exc, 'Fatal read error on pipe transport') |
| 508 | else: |
| 509 | if data: |
| 510 | self._protocol.data_received(data) |
| 511 | else: |
| 512 | if self._loop.get_debug(): |
| 513 | logger.info("%r was closed by peer", self) |
| 514 | self._closing = True |
| 515 | self._loop._remove_reader(self._fileno) |
| 516 | self._loop.call_soon(self._protocol.eof_received) |
| 517 | self._loop.call_soon(self._call_connection_lost, None) |
| 518 | |
| 519 | def pause_reading(self): |
| 520 | if self._closing or self._paused: |
| 521 | return |
| 522 | self._paused = True |
| 523 | self._loop._remove_reader(self._fileno) |
| 524 | if self._loop.get_debug(): |
| 525 | logger.debug("%r pauses reading", self) |
| 526 | |
| 527 | def resume_reading(self): |
| 528 | if self._closing or not self._paused: |
| 529 | return |
| 530 | self._paused = False |
| 531 | self._loop._add_reader(self._fileno, self._read_ready) |
| 532 | if self._loop.get_debug(): |
| 533 | logger.debug("%r resumes reading", self) |
| 534 | |
| 535 | def set_protocol(self, protocol): |
| 536 | self._protocol = protocol |
| 537 | |
| 538 | def get_protocol(self): |
| 539 | return self._protocol |
| 540 | |
| 541 | def is_closing(self): |
| 542 | return self._closing |
| 543 | |
| 544 | def close(self): |
| 545 | if not self._closing: |
| 546 | self._close(None) |
| 547 | |
| 548 | def __del__(self, _warn=warnings.warn): |
| 549 | if self._pipe is not None: |
| 550 | _warn(f"unclosed transport {self!r}", ResourceWarning, source=self) |
| 551 | self._pipe.close() |
| 552 | |
| 553 | def _fatal_error(self, exc, message='Fatal error on pipe transport'): |
| 554 | # should be called by exception handler only |
| 555 | if (isinstance(exc, OSError) and exc.errno == errno.EIO): |
| 556 | if self._loop.get_debug(): |
| 557 | logger.debug("%r: %s", self, message, exc_info=True) |
| 558 | else: |
| 559 | self._loop.call_exception_handler({ |
| 560 | 'message': message, |
| 561 | 'exception': exc, |
| 562 | 'transport': self, |
| 563 | 'protocol': self._protocol, |
| 564 | }) |
| 565 | self._close(exc) |
| 566 | |
| 567 | def _close(self, exc): |
| 568 | self._closing = True |
| 569 | self._loop._remove_reader(self._fileno) |
| 570 | self._loop.call_soon(self._call_connection_lost, exc) |
| 571 | |
| 572 | def _call_connection_lost(self, exc): |
| 573 | try: |
| 574 | self._protocol.connection_lost(exc) |
| 575 | finally: |
| 576 | self._pipe.close() |
| 577 | self._pipe = None |
| 578 | self._protocol = None |
| 579 | self._loop = None |
| 580 | |
| 581 | |
| 582 | class _UnixWritePipeTransport(transports._FlowControlMixin, |
| 583 | transports.WriteTransport): |
| 584 | |
| 585 | def __init__(self, loop, pipe, protocol, waiter=None, extra=None): |
| 586 | super().__init__(extra, loop) |
| 587 | self._extra['pipe'] = pipe |
| 588 | self._pipe = pipe |
| 589 | self._fileno = pipe.fileno() |
| 590 | self._protocol = protocol |
| 591 | self._buffer = bytearray() |
| 592 | self._conn_lost = 0 |
| 593 | self._closing = False # Set when close() or write_eof() called. |
| 594 | |
| 595 | mode = os.fstat(self._fileno).st_mode |
| 596 | is_char = stat.S_ISCHR(mode) |
| 597 | is_fifo = stat.S_ISFIFO(mode) |
| 598 | is_socket = stat.S_ISSOCK(mode) |
| 599 | if not (is_char or is_fifo or is_socket): |
| 600 | self._pipe = None |
| 601 | self._fileno = None |
| 602 | self._protocol = None |
| 603 | raise ValueError("Pipe transport is only for " |
| 604 | "pipes, sockets and character devices") |
| 605 | |
| 606 | os.set_blocking(self._fileno, False) |
| 607 | self._loop.call_soon(self._protocol.connection_made, self) |
| 608 | |
| 609 | # On AIX, the reader trick (to be notified when the read end of the |
| 610 | # socket is closed) only works for sockets. On other platforms it |
| 611 | # works for pipes and sockets. (Exception: OS X 10.4? Issue #19294.) |
| 612 | if is_socket or (is_fifo and not sys.platform.startswith("aix")): |
| 613 | # only start reading when connection_made() has been called |
| 614 | self._loop.call_soon(self._loop._add_reader, |
| 615 | self._fileno, self._read_ready) |
| 616 | |
| 617 | if waiter is not None: |
| 618 | # only wake up the waiter when connection_made() has been called |
| 619 | self._loop.call_soon(futures._set_result_unless_cancelled, |
| 620 | waiter, None) |
| 621 | |
| 622 | def __repr__(self): |
| 623 | info = [self.__class__.__name__] |
| 624 | if self._pipe is None: |
| 625 | info.append('closed') |
| 626 | elif self._closing: |
| 627 | info.append('closing') |
| 628 | info.append(f'fd={self._fileno}') |
| 629 | selector = getattr(self._loop, '_selector', None) |
| 630 | if self._pipe is not None and selector is not None: |
| 631 | polling = selector_events._test_selector_event( |
| 632 | selector, self._fileno, selectors.EVENT_WRITE) |
| 633 | if polling: |
| 634 | info.append('polling') |
| 635 | else: |
| 636 | info.append('idle') |
| 637 | |
| 638 | bufsize = self.get_write_buffer_size() |
| 639 | info.append(f'bufsize={bufsize}') |
| 640 | elif self._pipe is not None: |
| 641 | info.append('open') |
| 642 | else: |
| 643 | info.append('closed') |
| 644 | return '<{}>'.format(' '.join(info)) |
| 645 | |
| 646 | def get_write_buffer_size(self): |
| 647 | return len(self._buffer) |
| 648 | |
| 649 | def _read_ready(self): |
| 650 | # Pipe was closed by peer. |
| 651 | if self._loop.get_debug(): |
| 652 | logger.info("%r was closed by peer", self) |
| 653 | if self._buffer: |
| 654 | self._close(BrokenPipeError()) |
| 655 | else: |
| 656 | self._close() |
| 657 | |
| 658 | def write(self, data): |
| 659 | assert isinstance(data, (bytes, bytearray, memoryview)), repr(data) |
| 660 | if isinstance(data, bytearray): |
| 661 | data = memoryview(data) |
| 662 | if not data: |
| 663 | return |
| 664 | |
| 665 | if self._conn_lost or self._closing: |
| 666 | if self._conn_lost >= constants.LOG_THRESHOLD_FOR_CONNLOST_WRITES: |
| 667 | logger.warning('pipe closed by peer or ' |
| 668 | 'os.write(pipe, data) raised exception.') |
| 669 | self._conn_lost += 1 |
| 670 | return |
| 671 | |
| 672 | if not self._buffer: |
| 673 | # Attempt to send it right away first. |
| 674 | try: |
| 675 | n = os.write(self._fileno, data) |
| 676 | except (BlockingIOError, InterruptedError): |
| 677 | n = 0 |
| 678 | except (SystemExit, KeyboardInterrupt): |
| 679 | raise |
| 680 | except BaseException as exc: |
| 681 | self._conn_lost += 1 |
| 682 | self._fatal_error(exc, 'Fatal write error on pipe transport') |
| 683 | return |
| 684 | if n == len(data): |
| 685 | return |
| 686 | elif n > 0: |
| 687 | data = memoryview(data)[n:] |
| 688 | self._loop._add_writer(self._fileno, self._write_ready) |
| 689 | |
| 690 | self._buffer += data |
| 691 | self._maybe_pause_protocol() |
| 692 | |
| 693 | def _write_ready(self): |
| 694 | assert self._buffer, 'Data should not be empty' |
| 695 | |
| 696 | try: |
| 697 | n = os.write(self._fileno, self._buffer) |
| 698 | except (BlockingIOError, InterruptedError): |
| 699 | pass |
| 700 | except (SystemExit, KeyboardInterrupt): |
| 701 | raise |
| 702 | except BaseException as exc: |
| 703 | self._buffer.clear() |
| 704 | self._conn_lost += 1 |
| 705 | # Remove writer here, _fatal_error() doesn't it |
| 706 | # because _buffer is empty. |
| 707 | self._loop._remove_writer(self._fileno) |
| 708 | self._fatal_error(exc, 'Fatal write error on pipe transport') |
| 709 | else: |
| 710 | if n == len(self._buffer): |
| 711 | self._buffer.clear() |
| 712 | self._loop._remove_writer(self._fileno) |
| 713 | self._maybe_resume_protocol() # May append to buffer. |
| 714 | if self._closing: |
| 715 | self._loop._remove_reader(self._fileno) |
| 716 | self._call_connection_lost(None) |
| 717 | return |
| 718 | elif n > 0: |
| 719 | del self._buffer[:n] |
| 720 | |
| 721 | def can_write_eof(self): |
| 722 | return True |
| 723 | |
| 724 | def write_eof(self): |
| 725 | if self._closing: |
| 726 | return |
| 727 | assert self._pipe |
| 728 | self._closing = True |
| 729 | if not self._buffer: |
| 730 | self._loop._remove_reader(self._fileno) |
| 731 | self._loop.call_soon(self._call_connection_lost, None) |
| 732 | |
| 733 | def set_protocol(self, protocol): |
| 734 | self._protocol = protocol |
| 735 | |
| 736 | def get_protocol(self): |
| 737 | return self._protocol |
| 738 | |
| 739 | def is_closing(self): |
| 740 | return self._closing |
| 741 | |
| 742 | def close(self): |
| 743 | if self._pipe is not None and not self._closing: |
| 744 | # write_eof is all what we needed to close the write pipe |
| 745 | self.write_eof() |
| 746 | |
| 747 | def __del__(self, _warn=warnings.warn): |
| 748 | if self._pipe is not None: |
| 749 | _warn(f"unclosed transport {self!r}", ResourceWarning, source=self) |
| 750 | self._pipe.close() |
| 751 | |
| 752 | def abort(self): |
| 753 | self._close(None) |
| 754 | |
| 755 | def _fatal_error(self, exc, message='Fatal error on pipe transport'): |
| 756 | # should be called by exception handler only |
| 757 | if isinstance(exc, OSError): |
| 758 | if self._loop.get_debug(): |
| 759 | logger.debug("%r: %s", self, message, exc_info=True) |
| 760 | else: |
| 761 | self._loop.call_exception_handler({ |
| 762 | 'message': message, |
| 763 | 'exception': exc, |
| 764 | 'transport': self, |
| 765 | 'protocol': self._protocol, |
| 766 | }) |
| 767 | self._close(exc) |
| 768 | |
| 769 | def _close(self, exc=None): |
| 770 | self._closing = True |
| 771 | if self._buffer: |
| 772 | self._loop._remove_writer(self._fileno) |
| 773 | self._buffer.clear() |
| 774 | self._loop._remove_reader(self._fileno) |
| 775 | self._loop.call_soon(self._call_connection_lost, exc) |
| 776 | |
| 777 | def _call_connection_lost(self, exc): |
| 778 | try: |
| 779 | self._protocol.connection_lost(exc) |
| 780 | finally: |
| 781 | self._pipe.close() |
| 782 | self._pipe = None |
| 783 | self._protocol = None |
| 784 | self._loop = None |
| 785 | |
| 786 | |
| 787 | class _UnixSubprocessTransport(base_subprocess.BaseSubprocessTransport): |
| 788 | |
| 789 | def _start(self, args, shell, stdin, stdout, stderr, bufsize, **kwargs): |
| 790 | stdin_w = None |
| 791 | if stdin == subprocess.PIPE: |
| 792 | # Use a socket pair for stdin, since not all platforms |
| 793 | # support selecting read events on the write end of a |
| 794 | # socket (which we use in order to detect closing of the |
| 795 | # other end). Notably this is needed on AIX, and works |
| 796 | # just fine on other platforms. |
| 797 | stdin, stdin_w = socket.socketpair() |
| 798 | try: |
| 799 | self._proc = subprocess.Popen( |
| 800 | args, shell=shell, stdin=stdin, stdout=stdout, stderr=stderr, |
| 801 | universal_newlines=False, bufsize=bufsize, **kwargs) |
| 802 | if stdin_w is not None: |
| 803 | stdin.close() |
| 804 | self._proc.stdin = open(stdin_w.detach(), 'wb', buffering=bufsize) |
| 805 | stdin_w = None |
| 806 | finally: |
| 807 | if stdin_w is not None: |
| 808 | stdin.close() |
| 809 | stdin_w.close() |
| 810 | |
| 811 | |
| 812 | class AbstractChildWatcher: |
| 813 | """Abstract base class for monitoring child processes. |
| 814 | |
| 815 | Objects derived from this class monitor a collection of subprocesses and |
| 816 | report their termination or interruption by a signal. |
| 817 | |
| 818 | New callbacks are registered with .add_child_handler(). Starting a new |
| 819 | process must be done within a 'with' block to allow the watcher to suspend |
| 820 | its activity until the new process if fully registered (this is needed to |
| 821 | prevent a race condition in some implementations). |
| 822 | |
| 823 | Example: |
| 824 | with watcher: |
| 825 | proc = subprocess.Popen("sleep 1") |
| 826 | watcher.add_child_handler(proc.pid, callback) |
| 827 | |
| 828 | Notes: |
| 829 | Implementations of this class must be thread-safe. |
| 830 | |
| 831 | Since child watcher objects may catch the SIGCHLD signal and call |
| 832 | waitpid(-1), there should be only one active object per process. |
| 833 | """ |
| 834 | |
| 835 | def add_child_handler(self, pid, callback, *args): |
| 836 | """Register a new child handler. |
| 837 | |
| 838 | Arrange for callback(pid, returncode, *args) to be called when |
| 839 | process 'pid' terminates. Specifying another callback for the same |
| 840 | process replaces the previous handler. |
| 841 | |
| 842 | Note: callback() must be thread-safe. |
| 843 | """ |
| 844 | raise NotImplementedError() |
| 845 | |
| 846 | def remove_child_handler(self, pid): |
| 847 | """Removes the handler for process 'pid'. |
| 848 | |
| 849 | The function returns True if the handler was successfully removed, |
| 850 | False if there was nothing to remove.""" |
| 851 | |
| 852 | raise NotImplementedError() |
| 853 | |
| 854 | def attach_loop(self, loop): |
| 855 | """Attach the watcher to an event loop. |
| 856 | |
| 857 | If the watcher was previously attached to an event loop, then it is |
| 858 | first detached before attaching to the new loop. |
| 859 | |
| 860 | Note: loop may be None. |
| 861 | """ |
| 862 | raise NotImplementedError() |
| 863 | |
| 864 | def close(self): |
| 865 | """Close the watcher. |
| 866 | |
| 867 | This must be called to make sure that any underlying resource is freed. |
| 868 | """ |
| 869 | raise NotImplementedError() |
| 870 | |
| 871 | def is_active(self): |
| 872 | """Return ``True`` if the watcher is active and is used by the event loop. |
| 873 | |
| 874 | Return True if the watcher is installed and ready to handle process exit |
| 875 | notifications. |
| 876 | |
| 877 | """ |
| 878 | raise NotImplementedError() |
| 879 | |
| 880 | def __enter__(self): |
| 881 | """Enter the watcher's context and allow starting new processes |
| 882 | |
| 883 | This function must return self""" |
| 884 | raise NotImplementedError() |
| 885 | |
| 886 | def __exit__(self, a, b, c): |
| 887 | """Exit the watcher's context""" |
| 888 | raise NotImplementedError() |
| 889 | |
| 890 | |
Elliott Hughes | 96c2b6b | 2021-01-26 11:15:15 -0800 | [diff] [blame] | 891 | class PidfdChildWatcher(AbstractChildWatcher): |
| 892 | """Child watcher implementation using Linux's pid file descriptors. |
| 893 | |
| 894 | This child watcher polls process file descriptors (pidfds) to await child |
| 895 | process termination. In some respects, PidfdChildWatcher is a "Goldilocks" |
| 896 | child watcher implementation. It doesn't require signals or threads, doesn't |
| 897 | interfere with any processes launched outside the event loop, and scales |
| 898 | linearly with the number of subprocesses launched by the event loop. The |
| 899 | main disadvantage is that pidfds are specific to Linux, and only work on |
| 900 | recent (5.3+) kernels. |
| 901 | """ |
| 902 | |
| 903 | def __init__(self): |
| 904 | self._loop = None |
| 905 | self._callbacks = {} |
| 906 | |
| 907 | def __enter__(self): |
| 908 | return self |
| 909 | |
| 910 | def __exit__(self, exc_type, exc_value, exc_traceback): |
| 911 | pass |
| 912 | |
| 913 | def is_active(self): |
| 914 | return self._loop is not None and self._loop.is_running() |
| 915 | |
| 916 | def close(self): |
| 917 | self.attach_loop(None) |
| 918 | |
| 919 | def attach_loop(self, loop): |
| 920 | if self._loop is not None and loop is None and self._callbacks: |
| 921 | warnings.warn( |
| 922 | 'A loop is being detached ' |
| 923 | 'from a child watcher with pending handlers', |
| 924 | RuntimeWarning) |
| 925 | for pidfd, _, _ in self._callbacks.values(): |
| 926 | self._loop._remove_reader(pidfd) |
| 927 | os.close(pidfd) |
| 928 | self._callbacks.clear() |
| 929 | self._loop = loop |
| 930 | |
| 931 | def add_child_handler(self, pid, callback, *args): |
| 932 | existing = self._callbacks.get(pid) |
| 933 | if existing is not None: |
| 934 | self._callbacks[pid] = existing[0], callback, args |
| 935 | else: |
| 936 | pidfd = os.pidfd_open(pid) |
| 937 | self._loop._add_reader(pidfd, self._do_wait, pid) |
| 938 | self._callbacks[pid] = pidfd, callback, args |
| 939 | |
| 940 | def _do_wait(self, pid): |
| 941 | pidfd, callback, args = self._callbacks.pop(pid) |
| 942 | self._loop._remove_reader(pidfd) |
| 943 | try: |
| 944 | _, status = os.waitpid(pid, 0) |
| 945 | except ChildProcessError: |
| 946 | # The child process is already reaped |
| 947 | # (may happen if waitpid() is called elsewhere). |
| 948 | returncode = 255 |
| 949 | logger.warning( |
| 950 | "child process pid %d exit status already read: " |
| 951 | " will report returncode 255", |
| 952 | pid) |
| 953 | else: |
Dan Willemsen | c9fa001 | 2022-03-25 22:58:53 +0000 | [diff] [blame^] | 954 | returncode = waitstatus_to_exitcode(status) |
Elliott Hughes | 96c2b6b | 2021-01-26 11:15:15 -0800 | [diff] [blame] | 955 | |
| 956 | os.close(pidfd) |
| 957 | callback(pid, returncode, *args) |
| 958 | |
| 959 | def remove_child_handler(self, pid): |
| 960 | try: |
| 961 | pidfd, _, _ = self._callbacks.pop(pid) |
| 962 | except KeyError: |
| 963 | return False |
| 964 | self._loop._remove_reader(pidfd) |
| 965 | os.close(pidfd) |
| 966 | return True |
| 967 | |
| 968 | |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 969 | class BaseChildWatcher(AbstractChildWatcher): |
| 970 | |
| 971 | def __init__(self): |
| 972 | self._loop = None |
| 973 | self._callbacks = {} |
| 974 | |
| 975 | def close(self): |
| 976 | self.attach_loop(None) |
| 977 | |
| 978 | def is_active(self): |
| 979 | return self._loop is not None and self._loop.is_running() |
| 980 | |
| 981 | def _do_waitpid(self, expected_pid): |
| 982 | raise NotImplementedError() |
| 983 | |
| 984 | def _do_waitpid_all(self): |
| 985 | raise NotImplementedError() |
| 986 | |
| 987 | def attach_loop(self, loop): |
| 988 | assert loop is None or isinstance(loop, events.AbstractEventLoop) |
| 989 | |
| 990 | if self._loop is not None and loop is None and self._callbacks: |
| 991 | warnings.warn( |
| 992 | 'A loop is being detached ' |
| 993 | 'from a child watcher with pending handlers', |
| 994 | RuntimeWarning) |
| 995 | |
| 996 | if self._loop is not None: |
| 997 | self._loop.remove_signal_handler(signal.SIGCHLD) |
| 998 | |
| 999 | self._loop = loop |
| 1000 | if loop is not None: |
| 1001 | loop.add_signal_handler(signal.SIGCHLD, self._sig_chld) |
| 1002 | |
| 1003 | # Prevent a race condition in case a child terminated |
| 1004 | # during the switch. |
| 1005 | self._do_waitpid_all() |
| 1006 | |
| 1007 | def _sig_chld(self): |
| 1008 | try: |
| 1009 | self._do_waitpid_all() |
| 1010 | except (SystemExit, KeyboardInterrupt): |
| 1011 | raise |
| 1012 | except BaseException as exc: |
| 1013 | # self._loop should always be available here |
| 1014 | # as '_sig_chld' is added as a signal handler |
| 1015 | # in 'attach_loop' |
| 1016 | self._loop.call_exception_handler({ |
| 1017 | 'message': 'Unknown exception in SIGCHLD handler', |
| 1018 | 'exception': exc, |
| 1019 | }) |
| 1020 | |
| 1021 | |
| 1022 | class SafeChildWatcher(BaseChildWatcher): |
| 1023 | """'Safe' child watcher implementation. |
| 1024 | |
| 1025 | This implementation avoids disrupting other code spawning processes by |
| 1026 | polling explicitly each process in the SIGCHLD handler instead of calling |
| 1027 | os.waitpid(-1). |
| 1028 | |
| 1029 | This is a safe solution but it has a significant overhead when handling a |
| 1030 | big number of children (O(n) each time SIGCHLD is raised) |
| 1031 | """ |
| 1032 | |
| 1033 | def close(self): |
| 1034 | self._callbacks.clear() |
| 1035 | super().close() |
| 1036 | |
| 1037 | def __enter__(self): |
| 1038 | return self |
| 1039 | |
| 1040 | def __exit__(self, a, b, c): |
| 1041 | pass |
| 1042 | |
| 1043 | def add_child_handler(self, pid, callback, *args): |
| 1044 | self._callbacks[pid] = (callback, args) |
| 1045 | |
| 1046 | # Prevent a race condition in case the child is already terminated. |
| 1047 | self._do_waitpid(pid) |
| 1048 | |
| 1049 | def remove_child_handler(self, pid): |
| 1050 | try: |
| 1051 | del self._callbacks[pid] |
| 1052 | return True |
| 1053 | except KeyError: |
| 1054 | return False |
| 1055 | |
| 1056 | def _do_waitpid_all(self): |
| 1057 | |
| 1058 | for pid in list(self._callbacks): |
| 1059 | self._do_waitpid(pid) |
| 1060 | |
| 1061 | def _do_waitpid(self, expected_pid): |
| 1062 | assert expected_pid > 0 |
| 1063 | |
| 1064 | try: |
| 1065 | pid, status = os.waitpid(expected_pid, os.WNOHANG) |
| 1066 | except ChildProcessError: |
| 1067 | # The child process is already reaped |
| 1068 | # (may happen if waitpid() is called elsewhere). |
| 1069 | pid = expected_pid |
| 1070 | returncode = 255 |
| 1071 | logger.warning( |
| 1072 | "Unknown child process pid %d, will report returncode 255", |
| 1073 | pid) |
| 1074 | else: |
| 1075 | if pid == 0: |
| 1076 | # The child process is still alive. |
| 1077 | return |
| 1078 | |
Dan Willemsen | c9fa001 | 2022-03-25 22:58:53 +0000 | [diff] [blame^] | 1079 | returncode = waitstatus_to_exitcode(status) |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 1080 | if self._loop.get_debug(): |
| 1081 | logger.debug('process %s exited with returncode %s', |
| 1082 | expected_pid, returncode) |
| 1083 | |
| 1084 | try: |
| 1085 | callback, args = self._callbacks.pop(pid) |
| 1086 | except KeyError: # pragma: no cover |
| 1087 | # May happen if .remove_child_handler() is called |
| 1088 | # after os.waitpid() returns. |
| 1089 | if self._loop.get_debug(): |
| 1090 | logger.warning("Child watcher got an unexpected pid: %r", |
| 1091 | pid, exc_info=True) |
| 1092 | else: |
| 1093 | callback(pid, returncode, *args) |
| 1094 | |
| 1095 | |
| 1096 | class FastChildWatcher(BaseChildWatcher): |
| 1097 | """'Fast' child watcher implementation. |
| 1098 | |
| 1099 | This implementation reaps every terminated processes by calling |
| 1100 | os.waitpid(-1) directly, possibly breaking other code spawning processes |
| 1101 | and waiting for their termination. |
| 1102 | |
| 1103 | There is no noticeable overhead when handling a big number of children |
| 1104 | (O(1) each time a child terminates). |
| 1105 | """ |
| 1106 | def __init__(self): |
| 1107 | super().__init__() |
| 1108 | self._lock = threading.Lock() |
| 1109 | self._zombies = {} |
| 1110 | self._forks = 0 |
| 1111 | |
| 1112 | def close(self): |
| 1113 | self._callbacks.clear() |
| 1114 | self._zombies.clear() |
| 1115 | super().close() |
| 1116 | |
| 1117 | def __enter__(self): |
| 1118 | with self._lock: |
| 1119 | self._forks += 1 |
| 1120 | |
| 1121 | return self |
| 1122 | |
| 1123 | def __exit__(self, a, b, c): |
| 1124 | with self._lock: |
| 1125 | self._forks -= 1 |
| 1126 | |
| 1127 | if self._forks or not self._zombies: |
| 1128 | return |
| 1129 | |
| 1130 | collateral_victims = str(self._zombies) |
| 1131 | self._zombies.clear() |
| 1132 | |
| 1133 | logger.warning( |
| 1134 | "Caught subprocesses termination from unknown pids: %s", |
| 1135 | collateral_victims) |
| 1136 | |
| 1137 | def add_child_handler(self, pid, callback, *args): |
| 1138 | assert self._forks, "Must use the context manager" |
| 1139 | |
| 1140 | with self._lock: |
| 1141 | try: |
| 1142 | returncode = self._zombies.pop(pid) |
| 1143 | except KeyError: |
| 1144 | # The child is running. |
| 1145 | self._callbacks[pid] = callback, args |
| 1146 | return |
| 1147 | |
| 1148 | # The child is dead already. We can fire the callback. |
| 1149 | callback(pid, returncode, *args) |
| 1150 | |
| 1151 | def remove_child_handler(self, pid): |
| 1152 | try: |
| 1153 | del self._callbacks[pid] |
| 1154 | return True |
| 1155 | except KeyError: |
| 1156 | return False |
| 1157 | |
| 1158 | def _do_waitpid_all(self): |
| 1159 | # Because of signal coalescing, we must keep calling waitpid() as |
| 1160 | # long as we're able to reap a child. |
| 1161 | while True: |
| 1162 | try: |
| 1163 | pid, status = os.waitpid(-1, os.WNOHANG) |
| 1164 | except ChildProcessError: |
| 1165 | # No more child processes exist. |
| 1166 | return |
| 1167 | else: |
| 1168 | if pid == 0: |
| 1169 | # A child process is still alive. |
| 1170 | return |
| 1171 | |
Dan Willemsen | c9fa001 | 2022-03-25 22:58:53 +0000 | [diff] [blame^] | 1172 | returncode = waitstatus_to_exitcode(status) |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 1173 | |
| 1174 | with self._lock: |
| 1175 | try: |
| 1176 | callback, args = self._callbacks.pop(pid) |
| 1177 | except KeyError: |
| 1178 | # unknown child |
| 1179 | if self._forks: |
| 1180 | # It may not be registered yet. |
| 1181 | self._zombies[pid] = returncode |
| 1182 | if self._loop.get_debug(): |
| 1183 | logger.debug('unknown process %s exited ' |
| 1184 | 'with returncode %s', |
| 1185 | pid, returncode) |
| 1186 | continue |
| 1187 | callback = None |
| 1188 | else: |
| 1189 | if self._loop.get_debug(): |
| 1190 | logger.debug('process %s exited with returncode %s', |
| 1191 | pid, returncode) |
| 1192 | |
| 1193 | if callback is None: |
| 1194 | logger.warning( |
| 1195 | "Caught subprocess termination from unknown pid: " |
| 1196 | "%d -> %d", pid, returncode) |
| 1197 | else: |
| 1198 | callback(pid, returncode, *args) |
| 1199 | |
| 1200 | |
| 1201 | class MultiLoopChildWatcher(AbstractChildWatcher): |
| 1202 | """A watcher that doesn't require running loop in the main thread. |
| 1203 | |
| 1204 | This implementation registers a SIGCHLD signal handler on |
| 1205 | instantiation (which may conflict with other code that |
| 1206 | install own handler for this signal). |
| 1207 | |
| 1208 | The solution is safe but it has a significant overhead when |
| 1209 | handling a big number of processes (*O(n)* each time a |
| 1210 | SIGCHLD is received). |
| 1211 | """ |
| 1212 | |
| 1213 | # Implementation note: |
| 1214 | # The class keeps compatibility with AbstractChildWatcher ABC |
| 1215 | # To achieve this it has empty attach_loop() method |
| 1216 | # and doesn't accept explicit loop argument |
| 1217 | # for add_child_handler()/remove_child_handler() |
| 1218 | # but retrieves the current loop by get_running_loop() |
| 1219 | |
| 1220 | def __init__(self): |
| 1221 | self._callbacks = {} |
| 1222 | self._saved_sighandler = None |
| 1223 | |
| 1224 | def is_active(self): |
| 1225 | return self._saved_sighandler is not None |
| 1226 | |
| 1227 | def close(self): |
| 1228 | self._callbacks.clear() |
Dan Willemsen | c9fa001 | 2022-03-25 22:58:53 +0000 | [diff] [blame^] | 1229 | if self._saved_sighandler is None: |
| 1230 | return |
| 1231 | |
| 1232 | handler = signal.getsignal(signal.SIGCHLD) |
| 1233 | if handler != self._sig_chld: |
| 1234 | logger.warning("SIGCHLD handler was changed by outside code") |
| 1235 | else: |
| 1236 | signal.signal(signal.SIGCHLD, self._saved_sighandler) |
| 1237 | self._saved_sighandler = None |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 1238 | |
| 1239 | def __enter__(self): |
| 1240 | return self |
| 1241 | |
| 1242 | def __exit__(self, exc_type, exc_val, exc_tb): |
| 1243 | pass |
| 1244 | |
| 1245 | def add_child_handler(self, pid, callback, *args): |
| 1246 | loop = events.get_running_loop() |
| 1247 | self._callbacks[pid] = (loop, callback, args) |
| 1248 | |
| 1249 | # Prevent a race condition in case the child is already terminated. |
| 1250 | self._do_waitpid(pid) |
| 1251 | |
| 1252 | def remove_child_handler(self, pid): |
| 1253 | try: |
| 1254 | del self._callbacks[pid] |
| 1255 | return True |
| 1256 | except KeyError: |
| 1257 | return False |
| 1258 | |
| 1259 | def attach_loop(self, loop): |
| 1260 | # Don't save the loop but initialize itself if called first time |
| 1261 | # The reason to do it here is that attach_loop() is called from |
| 1262 | # unix policy only for the main thread. |
| 1263 | # Main thread is required for subscription on SIGCHLD signal |
Dan Willemsen | c9fa001 | 2022-03-25 22:58:53 +0000 | [diff] [blame^] | 1264 | if self._saved_sighandler is not None: |
| 1265 | return |
Dan Willemsen | 52aefcd | 2022-03-24 21:56:24 -0700 | [diff] [blame] | 1266 | |
Dan Willemsen | c9fa001 | 2022-03-25 22:58:53 +0000 | [diff] [blame^] | 1267 | self._saved_sighandler = signal.signal(signal.SIGCHLD, self._sig_chld) |
| 1268 | if self._saved_sighandler is None: |
| 1269 | logger.warning("Previous SIGCHLD handler was set by non-Python code, " |
| 1270 | "restore to default handler on watcher close.") |
| 1271 | self._saved_sighandler = signal.SIG_DFL |
| 1272 | |
| 1273 | # Set SA_RESTART to limit EINTR occurrences. |
| 1274 | signal.siginterrupt(signal.SIGCHLD, False) |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 1275 | |
| 1276 | def _do_waitpid_all(self): |
| 1277 | for pid in list(self._callbacks): |
| 1278 | self._do_waitpid(pid) |
| 1279 | |
| 1280 | def _do_waitpid(self, expected_pid): |
| 1281 | assert expected_pid > 0 |
| 1282 | |
| 1283 | try: |
| 1284 | pid, status = os.waitpid(expected_pid, os.WNOHANG) |
| 1285 | except ChildProcessError: |
| 1286 | # The child process is already reaped |
| 1287 | # (may happen if waitpid() is called elsewhere). |
| 1288 | pid = expected_pid |
| 1289 | returncode = 255 |
| 1290 | logger.warning( |
| 1291 | "Unknown child process pid %d, will report returncode 255", |
| 1292 | pid) |
| 1293 | debug_log = False |
| 1294 | else: |
| 1295 | if pid == 0: |
| 1296 | # The child process is still alive. |
| 1297 | return |
| 1298 | |
Dan Willemsen | c9fa001 | 2022-03-25 22:58:53 +0000 | [diff] [blame^] | 1299 | returncode = waitstatus_to_exitcode(status) |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 1300 | debug_log = True |
| 1301 | try: |
| 1302 | loop, callback, args = self._callbacks.pop(pid) |
| 1303 | except KeyError: # pragma: no cover |
| 1304 | # May happen if .remove_child_handler() is called |
| 1305 | # after os.waitpid() returns. |
| 1306 | logger.warning("Child watcher got an unexpected pid: %r", |
| 1307 | pid, exc_info=True) |
| 1308 | else: |
| 1309 | if loop.is_closed(): |
| 1310 | logger.warning("Loop %r that handles pid %r is closed", loop, pid) |
| 1311 | else: |
| 1312 | if debug_log and loop.get_debug(): |
| 1313 | logger.debug('process %s exited with returncode %s', |
| 1314 | expected_pid, returncode) |
| 1315 | loop.call_soon_threadsafe(callback, pid, returncode, *args) |
| 1316 | |
| 1317 | def _sig_chld(self, signum, frame): |
| 1318 | try: |
| 1319 | self._do_waitpid_all() |
| 1320 | except (SystemExit, KeyboardInterrupt): |
| 1321 | raise |
| 1322 | except BaseException: |
| 1323 | logger.warning('Unknown exception in SIGCHLD handler', exc_info=True) |
| 1324 | |
| 1325 | |
| 1326 | class ThreadedChildWatcher(AbstractChildWatcher): |
| 1327 | """Threaded child watcher implementation. |
| 1328 | |
| 1329 | The watcher uses a thread per process |
| 1330 | for waiting for the process finish. |
| 1331 | |
| 1332 | It doesn't require subscription on POSIX signal |
| 1333 | but a thread creation is not free. |
| 1334 | |
| 1335 | The watcher has O(1) complexity, its performance doesn't depend |
| 1336 | on amount of spawn processes. |
| 1337 | """ |
| 1338 | |
| 1339 | def __init__(self): |
| 1340 | self._pid_counter = itertools.count(0) |
| 1341 | self._threads = {} |
| 1342 | |
| 1343 | def is_active(self): |
| 1344 | return True |
| 1345 | |
| 1346 | def close(self): |
| 1347 | self._join_threads() |
| 1348 | |
| 1349 | def _join_threads(self): |
| 1350 | """Internal: Join all non-daemon threads""" |
| 1351 | threads = [thread for thread in list(self._threads.values()) |
| 1352 | if thread.is_alive() and not thread.daemon] |
| 1353 | for thread in threads: |
| 1354 | thread.join() |
| 1355 | |
| 1356 | def __enter__(self): |
| 1357 | return self |
| 1358 | |
| 1359 | def __exit__(self, exc_type, exc_val, exc_tb): |
| 1360 | pass |
| 1361 | |
| 1362 | def __del__(self, _warn=warnings.warn): |
| 1363 | threads = [thread for thread in list(self._threads.values()) |
| 1364 | if thread.is_alive()] |
| 1365 | if threads: |
| 1366 | _warn(f"{self.__class__} has registered but not finished child processes", |
| 1367 | ResourceWarning, |
| 1368 | source=self) |
| 1369 | |
| 1370 | def add_child_handler(self, pid, callback, *args): |
| 1371 | loop = events.get_running_loop() |
| 1372 | thread = threading.Thread(target=self._do_waitpid, |
| 1373 | name=f"waitpid-{next(self._pid_counter)}", |
| 1374 | args=(loop, pid, callback, args), |
| 1375 | daemon=True) |
| 1376 | self._threads[pid] = thread |
| 1377 | thread.start() |
| 1378 | |
| 1379 | def remove_child_handler(self, pid): |
| 1380 | # asyncio never calls remove_child_handler() !!! |
| 1381 | # The method is no-op but is implemented because |
Dan Willemsen | c9fa001 | 2022-03-25 22:58:53 +0000 | [diff] [blame^] | 1382 | # abstract base classes require it. |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 1383 | return True |
| 1384 | |
| 1385 | def attach_loop(self, loop): |
| 1386 | pass |
| 1387 | |
| 1388 | def _do_waitpid(self, loop, expected_pid, callback, args): |
| 1389 | assert expected_pid > 0 |
| 1390 | |
| 1391 | try: |
| 1392 | pid, status = os.waitpid(expected_pid, 0) |
| 1393 | except ChildProcessError: |
| 1394 | # The child process is already reaped |
| 1395 | # (may happen if waitpid() is called elsewhere). |
| 1396 | pid = expected_pid |
| 1397 | returncode = 255 |
| 1398 | logger.warning( |
| 1399 | "Unknown child process pid %d, will report returncode 255", |
| 1400 | pid) |
| 1401 | else: |
Dan Willemsen | c9fa001 | 2022-03-25 22:58:53 +0000 | [diff] [blame^] | 1402 | returncode = waitstatus_to_exitcode(status) |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 1403 | if loop.get_debug(): |
| 1404 | logger.debug('process %s exited with returncode %s', |
| 1405 | expected_pid, returncode) |
| 1406 | |
| 1407 | if loop.is_closed(): |
| 1408 | logger.warning("Loop %r that handles pid %r is closed", loop, pid) |
| 1409 | else: |
| 1410 | loop.call_soon_threadsafe(callback, pid, returncode, *args) |
| 1411 | |
| 1412 | self._threads.pop(expected_pid) |
| 1413 | |
| 1414 | |
| 1415 | class _UnixDefaultEventLoopPolicy(events.BaseDefaultEventLoopPolicy): |
| 1416 | """UNIX event loop policy with a watcher for child processes.""" |
| 1417 | _loop_factory = _UnixSelectorEventLoop |
| 1418 | |
| 1419 | def __init__(self): |
| 1420 | super().__init__() |
| 1421 | self._watcher = None |
| 1422 | |
| 1423 | def _init_watcher(self): |
| 1424 | with events._lock: |
| 1425 | if self._watcher is None: # pragma: no branch |
| 1426 | self._watcher = ThreadedChildWatcher() |
Elliott Hughes | 96c2b6b | 2021-01-26 11:15:15 -0800 | [diff] [blame] | 1427 | if threading.current_thread() is threading.main_thread(): |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 1428 | self._watcher.attach_loop(self._local._loop) |
| 1429 | |
| 1430 | def set_event_loop(self, loop): |
| 1431 | """Set the event loop. |
| 1432 | |
| 1433 | As a side effect, if a child watcher was set before, then calling |
| 1434 | .set_event_loop() from the main thread will call .attach_loop(loop) on |
| 1435 | the child watcher. |
| 1436 | """ |
| 1437 | |
| 1438 | super().set_event_loop(loop) |
| 1439 | |
| 1440 | if (self._watcher is not None and |
Elliott Hughes | 96c2b6b | 2021-01-26 11:15:15 -0800 | [diff] [blame] | 1441 | threading.current_thread() is threading.main_thread()): |
Jingwen Chen | 475b3cc | 2021-01-05 21:45:16 -0500 | [diff] [blame] | 1442 | self._watcher.attach_loop(loop) |
| 1443 | |
| 1444 | def get_child_watcher(self): |
| 1445 | """Get the watcher for child processes. |
| 1446 | |
| 1447 | If not yet set, a ThreadedChildWatcher object is automatically created. |
| 1448 | """ |
| 1449 | if self._watcher is None: |
| 1450 | self._init_watcher() |
| 1451 | |
| 1452 | return self._watcher |
| 1453 | |
| 1454 | def set_child_watcher(self, watcher): |
| 1455 | """Set the watcher for child processes.""" |
| 1456 | |
| 1457 | assert watcher is None or isinstance(watcher, AbstractChildWatcher) |
| 1458 | |
| 1459 | if self._watcher is not None: |
| 1460 | self._watcher.close() |
| 1461 | |
| 1462 | self._watcher = watcher |
| 1463 | |
| 1464 | |
| 1465 | SelectorEventLoop = _UnixSelectorEventLoop |
| 1466 | DefaultEventLoopPolicy = _UnixDefaultEventLoopPolicy |