问题
In python 2.6 under Linux, I can use the following to handle a TERM signal:
import signal
def handleSigTERM():
shutdown()
signal.signal(signal.SIGTERM, handleSigTERM)
Is there any way to setup a handler for all signals received by the process, other than just setting them up one-at-a-time?
回答1:
You could just loop through the signals in the signal module and set them up.
for i in [x for x in dir(signal) if x.startswith("SIG")]:
try:
signum = getattr(signal,i)
signal.signal(signum,sighandler)
except (OSError, RuntimeError) as m: #OSError for Python3, RuntimeError for 2
print ("Skipping {}".format(i))
回答2:
As of Python 3.5, the signal constants are defined as an enum, enabling a nicer approach:
import signal
catchable_sigs = set(signal.Signals) - {signal.SIGKILL, signal.SIGSTOP}
for sig in catchable_sigs:
signal.signal(sig, print) # Substitute handler of choice for `print`
回答3:
If you want to get rid of the try, just ignore signals that cannot be caught.
#!/usr/bin/env python
# https://stackoverflow.com/questions/2148888/python-trap-all-signals
import os
import sys
import time
import signal
SIGNALS_TO_NAMES_DICT = dict((getattr(signal, n), n) \
for n in dir(signal) if n.startswith('SIG') and '_' not in n )
def receive_signal(signum, stack):
if signum in [1,2,3,15]:
print 'Caught signal %s (%s), exiting.' % (SIGNALS_TO_NAMES_DICT[signum], str(signum))
sys.exit()
else:
print 'Caught signal %s (%s), ignoring.' % (SIGNALS_TO_NAMES_DICT[signum], str(signum))
def main():
uncatchable = ['SIG_DFL','SIGSTOP','SIGKILL']
for i in [x for x in dir(signal) if x.startswith("SIG")]:
if not i in uncatchable:
signum = getattr(signal,i)
signal.signal(signum,receive_signal)
print('My PID: %s' % os.getpid())
while True:
time.sleep(1)
main()
回答4:
Here's a 2/3 compatible way which doesn't have as many pitfalls as the others:
from itertools import count
import signal
def set_all_signal_signals(handler):
"""Set all signals to a particular handler."""
for signalnum in count(1):
try:
signal.signal(signalnum, handler)
print("set {}".format(signalnum))
except (OSError, RuntimeError):
# Invalid argument such as signals that can't be blocked
pass
except ValueError:
# Signal out of range
break
Since signalnum
is just a number, iterate over 1 to out of range setting the signal to a particular handle.
回答5:
Works on Windows 10 and Python 3.7:
import signal
import time
def sighandler(signal,frame):
print("signal",sig,frame)
return
catchable_sigs = set(signal.Signals)
for sig in catchable_sigs:
try:
signal.signal(sig, sighandler)
print("Setting ",sig)
print ("value {}".format(sig))
except (ValueError, OSError, RuntimeError) as m:
print("Skipping ",sig)
print ("Value {}".format(sig))
# press some keys or issue kill
x = 0
while x < 5:
time.sleep(4)
x += 1
Results:
Skipping Signals.CTRL_C_EVENT
Value 0
Skipping Signals.CTRL_BREAK_EVENT
Value 1
Setting Signals.SIGINT
value 2
Setting Signals.SIGILL
value 4
Setting Signals.SIGFPE
value 8
Setting Signals.SIGSEGV
value 11
Setting Signals.SIGTERM
value 15
Setting Signals.SIGBREAK
value 21
Setting Signals.SIGABRT
value 22
回答6:
That code won't work in the current version of python. There are many variables starting with SIG with the same value. For instance, SIGHUP and SIG_UNBLOCK are both 1. The only way I could think of to get a list of actual signals was to just make it myself.
from signal import *
signals = {
SIGABRT: 'SIGABRT',
SIGALRM: 'SIGALRM',
SIGBUS: 'SIGBUS',
SIGCHLD: 'SIGCHLD',
SIGCONT: 'SIGCONT',
SIGFPE: 'SIGFPE',
SIGHUP: 'SIGHUP',
SIGILL: 'SIGILL',
SIGINT: 'SIGINT',
SIGPIPE: 'SIGPIPE',
SIGPOLL: 'SIGPOLL',
SIGPROF: 'SIGPROF',
SIGQUIT: 'SIGQUIT',
SIGSEGV: 'SIGSEGV',
SIGSYS: 'SIGSYS',
SIGTERM: 'SIGTERM',
SIGTRAP: 'SIGTRAP',
SIGTSTP: 'SIGTSTP',
SIGTTIN: 'SIGTTIN',
SIGTTOU: 'SIGTTOU',
SIGURG: 'SIGURG',
SIGUSR1: 'SIGUSR1',
SIGUSR2: 'SIGUSR2',
SIGVTALRM: 'SIGVTALRM',
SIGXCPU: 'SIGXCPU',
SIGXFSZ: 'SIGXFSZ',
}
for num in signals:
signal(num, h)
来源:https://stackoverflow.com/questions/2148888/python-trap-all-signals