#!/usr/bin/env python
## Copyright (C) 2006 Red Hat, Inc.
## Written by Gary Benson <gbenson@redhat.com>
##
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
import os
import signal
import sys
import syslog
import time
import traceback
class Error(Exception):
pass
def which(cmd):
for path in os.environ["PATH"].split(":"):
path = os.path.join(path, cmd)
if os.access(path, os.X_OK):
return path
raise Error, "no %s in (%s)" % (cmd, os.environ["PATH"])
def pidof(cmd):
if not os.path.dirname(cmd):
cmd = which(cmd)
cmd = os.path.realpath(cmd)
pids = []
seen = False
for pid in os.listdir("/proc"):
try:
pid = int(pid)
except ValueError:
continue
seen = True
path = os.path.join("/proc", str(pid), "exe")
try:
if os.path.realpath(path) == cmd:
pids.append(pid)
except OSError:
pass
assert seen
return pids
class Watcher:
def __init__(self, cmd, args):
self.name = os.path.basename(cmd)
if not os.path.dirname(cmd):
cmd = which(cmd)
self.cmd = os.path.realpath(cmd)
self.args = args
def start(self):
syslog.syslog(syslog.LOG_NOTICE, "starting %s" % self.name)
pid = os.fork()
if pid == 0:
os.execv(self.cmd, [self.name] + self.args)
status = os.waitpid(pid, 0)[1]
if os.WIFSIGNALED(status):
raise Error, "%s killed with signal %d" % (
self.cmd, os.WTERMSIG(status))
if not os.WIFEXITED(status):
raise RuntimeError, "os.waitpid returned %d" % status
status = os.WEXITSTATUS(status)
if status:
raise Error, "%s exited with code %d" % (self.cmd, status)
pids = pidof(self.cmd)
if not pids:
raise Error, "%s is not running!" % self.cmd
if len(pids) != 1:
pids = ", ".join(map(str, pids))
raise Error, "multiple copies of %s running!" % (self.cmd, pids)
self.pid = pids[0]
syslog.syslog(syslog.LOG_NOTICE, "%s started" % self.name)
def detach(self):
if os.fork():
sys.exit()
os.setsid()
if os.fork():
sys.exit()
null = os.open("/dev/null", os.O_RDWR)
for fd in range(3):
os.dup2(null, fd)
def isrunning(self):
return os.access(os.path.join("/proc", str(self.pid)), os.F_OK)
def stop(self):
syslog.syslog(syslog.LOG_NOTICE, "stopping %s" % self.name)
for sig in (signal.SIGTERM, signal.SIGKILL):
try:
os.kill(self.pid, signal.SIGTERM)
except OSError:
continue
for i in xrange(30):
if not self.isrunning():
break
time.sleep(1)
if not self.isrunning():
break
if self.isrunning():
raise Error, "%s (%d) didn't die!" % (self.name, self.pid)
def signal(self, num, frame):
if num == signal.SIGHUP:
self.do_restart = True
if num == signal.SIGTERM:
self.do_exit = True
def run(self):
syslog.openlog("vpnc-watch", syslog.LOG_PID, syslog.LOG_DAEMON)
pids = pidof(self.cmd)
if pids:
pids = ", ".join(map(str, pids))
raise Error, "%s already running (%s)" % (self.cmd, pids)
self.start()
self.detach()
try:
signal.signal(signal.SIGHUP, self.signal)
signal.signal(signal.SIGTERM, self.signal)
self.do_exit = False
while not self.do_exit:
self.do_restart = False
time.sleep(1)
running = self.isrunning()
if not running:
syslog.syslog(syslog.LOG_WARNING, "%s died" % self.name)
elif self.do_exit or self.do_restart:
self.stop()
if self.do_restart or not running:
self.start()
syslog.syslog(syslog.LOG_INFO, "exiting")
except Error, e:
syslog.syslog(syslog.LOG_ERR, "error: " + str(e))
sys.exit(1)
except:
msg = "".join(apply(traceback.format_exception, sys.exc_info()))
for line in msg.split("\n"):
if line:
syslog.syslog(syslog.LOG_ERR, line)
sys.exit(1)
if __name__ == "__main__":
if len(sys.argv) < 2:
print >>sys.stderr, "usage: %s COMMAND [ARGS]" % sys.argv[0]
sys.exit(1)
try:
Watcher(sys.argv[1], sys.argv[2:]).run()
except Error, e:
print >>sys.stderr, "error:", e
sys.exit(1)
