122 lines
4.2 KiB
Python
122 lines
4.2 KiB
Python
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"""A parent poller for unix."""
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# Copyright (c) IPython Development Team.
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# Distributed under the terms of the Modified BSD License.
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try:
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import ctypes
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except ImportError:
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ctypes = None # type:ignore[assignment]
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import os
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import platform
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import signal
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import time
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import warnings
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from _thread import interrupt_main # Py 3
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from threading import Thread
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from traitlets.log import get_logger
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class ParentPollerUnix(Thread):
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"""A Unix-specific daemon thread that terminates the program immediately
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when the parent process no longer exists.
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"""
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def __init__(self):
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"""Initialize the poller."""
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super().__init__()
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self.daemon = True
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def run(self):
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"""Run the poller."""
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# We cannot use os.waitpid because it works only for child processes.
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from errno import EINTR
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while True:
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try:
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if os.getppid() == 1:
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get_logger().warning("Parent appears to have exited, shutting down.")
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os._exit(1)
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time.sleep(1.0)
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except OSError as e:
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if e.errno == EINTR:
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continue
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raise
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class ParentPollerWindows(Thread):
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"""A Windows-specific daemon thread that listens for a special event that
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signals an interrupt and, optionally, terminates the program immediately
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when the parent process no longer exists.
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"""
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def __init__(self, interrupt_handle=None, parent_handle=None):
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"""Create the poller. At least one of the optional parameters must be
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provided.
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Parameters
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----------
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interrupt_handle : HANDLE (int), optional
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If provided, the program will generate a Ctrl+C event when this
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handle is signaled.
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parent_handle : HANDLE (int), optional
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If provided, the program will terminate immediately when this
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handle is signaled.
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"""
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assert interrupt_handle or parent_handle
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super().__init__()
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if ctypes is None:
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msg = "ParentPollerWindows requires ctypes" # type:ignore[unreachable]
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raise ImportError(msg)
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self.daemon = True
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self.interrupt_handle = interrupt_handle
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self.parent_handle = parent_handle
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def run(self):
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"""Run the poll loop. This method never returns."""
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try:
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from _winapi import INFINITE, WAIT_OBJECT_0 # type:ignore[attr-defined]
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except ImportError:
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from _subprocess import INFINITE, WAIT_OBJECT_0
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# Build the list of handle to listen on.
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handles = []
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if self.interrupt_handle:
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handles.append(self.interrupt_handle)
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if self.parent_handle:
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handles.append(self.parent_handle)
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arch = platform.architecture()[0]
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c_int = ctypes.c_int64 if arch.startswith("64") else ctypes.c_int
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# Listen forever.
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while True:
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result = ctypes.windll.kernel32.WaitForMultipleObjects( # type:ignore[attr-defined]
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len(handles), # nCount
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(c_int * len(handles))(*handles), # lpHandles
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False, # bWaitAll
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INFINITE,
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) # dwMilliseconds
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if WAIT_OBJECT_0 <= result < len(handles):
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handle = handles[result - WAIT_OBJECT_0]
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if handle == self.interrupt_handle:
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# check if signal handler is callable
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# to avoid 'int not callable' error (Python issue #23395)
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if callable(signal.getsignal(signal.SIGINT)):
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interrupt_main()
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elif handle == self.parent_handle:
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get_logger().warning("Parent appears to have exited, shutting down.")
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os._exit(1)
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elif result < 0:
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# wait failed, just give up and stop polling.
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warnings.warn(
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"""Parent poll failed. If the frontend dies,
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the kernel may be left running. Please let us know
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about your system (bitness, Python, etc.) at
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ipython-dev@scipy.org""",
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stacklevel=2,
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)
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return
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