Get pid of the process which has triggered some signal

Question

Is it possible to find out the process id of the process which has caused some signal. In my scenario, I have multiple children of a process running, and I want to know which one of them sent the signal.

Answer 1

It is (finally!) very simple with python 3.

The following is tested with python 3.3.3:

#! /usr/bin/python3

import signal
import time, os

def callme(num, frame):
    pass

# register the callback:
signal.signal(signal.SIGUSR1, callme)

print("py: Hi, I'm %d, talk to me with 'kill -SIGUSR1 %d'"
      % (os.getpid(),os.getpid()))

# wait for signal info:
while True:
    siginfo = signal.sigwaitinfo({signal.SIGUSR1})
    print("py: got %d from %d by user %d\n" % (siginfo.si_signo,
                                             siginfo.si_pid,
                                             siginfo.si_uid))