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Mini Shell
Mini Shell
#! /usr/bin/python
""" An executable which proxies for a subprocess; upon a signal, it sends that
signal to the process identified by a pidfile. """
import os
import sys
import signal
import time
class PidProxy:
pid = None
def __init__(self, args):
self.setsignals()
try:
self.pidfile, cmdargs = args[1], args[2:]
self.command = os.path.abspath(cmdargs[0])
self.cmdargs = cmdargs
except (ValueError, IndexError):
self.usage()
sys.exit(1)
def go(self):
self.pid = os.spawnv(os.P_NOWAIT, self.command, self.cmdargs)
while 1:
time.sleep(5)
try:
pid, sts = os.waitpid(-1, os.WNOHANG)
except OSError:
pid, sts = None, None
if pid:
break
def usage(self):
print "pidproxy.py <pidfile name> <command> [<cmdarg1> ...]"
def setsignals(self):
signal.signal(signal.SIGTERM, self.passtochild)
signal.signal(signal.SIGHUP, self.passtochild)
signal.signal(signal.SIGINT, self.passtochild)
signal.signal(signal.SIGUSR1, self.passtochild)
signal.signal(signal.SIGUSR2, self.passtochild)
signal.signal(signal.SIGQUIT, self.passtochild)
signal.signal(signal.SIGCHLD, self.reap)
def reap(self, sig, frame):
# do nothing, we reap our child synchronously
pass
def passtochild(self, sig, frame):
try:
pid = int(open(self.pidfile, 'r').read().strip())
except:
pid = None
print "Can't read child pidfile %s!" % self.pidfile
return
os.kill(pid, sig)
if sig in [signal.SIGTERM, signal.SIGINT, signal.SIGQUIT]:
sys.exit(0)
def main():
pp = PidProxy(sys.argv)
pp.go()
if __name__ == '__main__':
main()
Zerion Mini Shell 1.0