File size: 5,188 Bytes
f618189 | 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 | """A parent poller for unix."""
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
try:
import ctypes
except ImportError:
ctypes = None # type:ignore[assignment]
import os
import platform
import signal
import time
import warnings
from _thread import interrupt_main # Py 3
from threading import Thread
from traitlets.log import get_logger
class ParentPollerUnix(Thread):
"""A Unix-specific daemon thread that terminates the program immediately
when the parent process no longer exists.
"""
def __init__(self, parent_pid=0):
"""Initialize the poller.
Parameters
----------
parent_handle : int, optional
If provided, the program will terminate immediately when
process parent is no longer this original parent.
"""
super().__init__()
self.parent_pid = parent_pid
self.daemon = True
def run(self):
"""Run the poller."""
# We cannot use os.waitpid because it works only for child processes.
from errno import EINTR
# before start, check if the passed-in parent pid is valid
original_ppid = os.getppid()
if original_ppid != self.parent_pid:
self.parent_pid = 0
get_logger().debug(
"%s: poll for parent change with original parent pid=%d",
type(self).__name__,
self.parent_pid,
)
while True:
try:
ppid = os.getppid()
parent_is_init = not self.parent_pid and ppid == 1
parent_has_changed = self.parent_pid and ppid != self.parent_pid
if parent_is_init or parent_has_changed:
get_logger().warning("Parent appears to have exited, shutting down.")
os._exit(1)
time.sleep(1.0)
except OSError as e:
if e.errno == EINTR:
continue
raise
class ParentPollerWindows(Thread):
"""A Windows-specific daemon thread that listens for a special event that
signals an interrupt and, optionally, terminates the program immediately
when the parent process no longer exists.
"""
def __init__(self, interrupt_handle=None, parent_handle=None):
"""Create the poller. At least one of the optional parameters must be
provided.
Parameters
----------
interrupt_handle : HANDLE (int), optional
If provided, the program will generate a Ctrl+C event when this
handle is signaled.
parent_handle : HANDLE (int), optional
If provided, the program will terminate immediately when this
handle is signaled.
"""
assert interrupt_handle or parent_handle
super().__init__()
if ctypes is None:
msg = "ParentPollerWindows requires ctypes" # type:ignore[unreachable]
raise ImportError(msg)
self.daemon = True
self.interrupt_handle = interrupt_handle
self.parent_handle = parent_handle
def run(self):
"""Run the poll loop. This method never returns."""
try:
from _winapi import INFINITE, WAIT_OBJECT_0 # type:ignore[attr-defined]
except ImportError:
from _subprocess import INFINITE, WAIT_OBJECT_0
# Build the list of handle to listen on.
handles = []
if self.interrupt_handle:
handles.append(self.interrupt_handle)
if self.parent_handle:
handles.append(self.parent_handle)
arch = platform.architecture()[0]
c_int = ctypes.c_int64 if arch.startswith("64") else ctypes.c_int
# Listen forever.
while True:
result = ctypes.windll.kernel32.WaitForMultipleObjects( # type:ignore[attr-defined]
len(handles), # nCount
(c_int * len(handles))(*handles), # lpHandles
False, # bWaitAll
INFINITE,
) # dwMilliseconds
if WAIT_OBJECT_0 <= result < len(handles):
handle = handles[result - WAIT_OBJECT_0]
ctypes.windll.kernel32.ResetEvent(handle) # type:ignore[attr-defined]
if handle == self.interrupt_handle:
# check if signal handler is callable
# to avoid 'int not callable' error (Python issue #23395)
if callable(signal.getsignal(signal.SIGINT)):
interrupt_main()
elif handle == self.parent_handle:
get_logger().warning("Parent appears to have exited, shutting down.")
os._exit(1)
elif result < 0:
# wait failed, just give up and stop polling.
warnings.warn(
"""Parent poll failed. If the frontend dies,
the kernel may be left running. Please let us know
about your system (bitness, Python, etc.) at
ipython-dev@scipy.org""",
stacklevel=2,
)
return
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