##############################################################################
#
# Copyright (c) 2001 Zope Corporation and Contributors. All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.0 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE
#
##############################################################################
"""Signal handling dispatcher."""
__version__='$Revision: 1.2 $'[11:-2]
import Daemon
import sys, os
import signal, zLOG
class SignalHandler:
def __init__(self):
self.registry = {}
def registerHandler(self, signum, handler):
"""Register a handler function that will be called when the process
recieves the signal signum. The signum argument must be a signal
constant such as SIGTERM. The handler argument must be a function
or method that takes no arguments. Note that handlers will not
be called on non-posix platforms."""
if os.name != 'posix':
return
items = self.registry.get(signum)
if items is None:
items = self.registry[signum] = []
signal.signal(signum, self.signalHandler)
signame = Daemon.get_signal_name(signum)
zLOG.LOG('Z2', zLOG.BLATHER, "Installed sighandler for %s" % (
signame
))
items.insert(0, handler)
def getRegisteredSignals(self):
"""Return a list of the signals that have handlers registered. This
is used to pass the signals through to the ZDaemon code."""
return self.registry.keys()
def signalHandler(self, signum, frame):
"""Meta signal handler that dispatches to registered handlers."""
signame = Daemon.get_signal_name(signum)
zLOG.LOG('Z2', zLOG.INFO , "Caught signal %s" % signame)
for handler in self.registry.get(signum, []):
# Never let a bad handler prevent the standard signal
# handlers from running.
try: handler()
except SystemExit:
# if we trap SystemExit, we can't restart
raise
except:
zLOG.LOG('Z2', zLOG.WARNING,
'A handler for %s failed!' % signame,
error=sys.exc_info())
# The SignalHandler is actually a singleton.
SignalHandler = SignalHandler()
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