#!/usr/bin/env python
"""
Found at:
http://www.jejik.com/articles/2007/02/a_simple_unix_linux_daemon_in_python/

--> mentioned in the comments below the code
#5 Anonymous Coward Posted on 2008-11-26@16:37
What is the license on this code? Can I have it under GPL?
#6 Sander Marechal (http://www.jejik.com) Posted on 2008-11-26@16:40
@Anonymous Coward This is really basic stuff and not very original. It's Public Domain, so do with it as you please.

"""
import sys, os, time, atexit
from signal import SIGTERM

class Daemon:
    """
    A generic daemon class.

    Usage: subclass the Daemon class and override the run() method
    """
    def __init__(self, pidfile, stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'):
        self.stdin = stdin
        self.stdout = stdout
        self.stderr = stderr
        self.pidfile = pidfile

    def daemonize(self):
        """
        do the UNIX double-fork magic, see Stevens' "Advanced
        Programming in the UNIX Environment" for details (ISBN 0201563177)
        http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC16
        """
        try:
            pid = os.fork()
            if pid > 0:
                # exit first parent
                sys.exit(0)
        except OSError, e:
            sys.stderr.write("fork #1 failed: %d (%s)\n" % (e.errno, e.strerror))
            sys.exit(1)

        # decouple from parent environment
        os.chdir("/")
        os.setsid()
        os.umask(0)

        # do second fork
        try:
            pid = os.fork()
            if pid > 0:
                # exit from second parent
                sys.exit(0)
        except OSError, e:
            sys.stderr.write("fork #2 failed: %d (%s)\n" % (e.errno, e.strerror))
            sys.exit(1)

        # redirect standard file descriptors
        sys.stdout.flush()
        sys.stderr.flush()
        si = file(self.stdin, 'r')
        so = file(self.stdout, 'a+')
        se = file(self.stderr, 'a+', 0)
        os.dup2(si.fileno(), sys.stdin.fileno())
        os.dup2(so.fileno(), sys.stdout.fileno())
        os.dup2(se.fileno(), sys.stderr.fileno())

        # write pidfile
        atexit.register(self.delpid)
        pid = str(os.getpid())
        file(self.pidfile,'w+').write("%s\n" % pid)

    def delpid(self):
        os.remove(self.pidfile)

    def start(self):
        """
        Start the daemon
        """
        # Check for a pidfile to see if the daemon already runs
        try:
            pf = file(self.pidfile,'r')
            pid = int(pf.read().strip())
            pf.close()
        except IOError:
            pid = None

        if pid:
            message = "pidfile %s already exist. Daemon already running?\n"
            sys.stderr.write(message % self.pidfile)
            sys.exit(1)

        # Start the daemon
        self.daemonize()
        self.run()

    def stop(self):
        """
        Stop the daemon
        """
        # Get the pid from the pidfile
        try:
            pf = file(self.pidfile,'r')
            pid = int(pf.read().strip())
            pf.close()
        except IOError:
            pid = None

        if not pid:
            message = "pidfile %s does not exist. Daemon not running?\n"
            sys.stderr.write(message % self.pidfile)
            return # not an error in a restart

        # Try killing the daemon process
        try:
            while 1:
                os.kill(pid, SIGTERM)
                time.sleep(0.1)
        except OSError, err:
            err = str(err)
            if err.find("No such process") > 0:
                if os.path.exists(self.pidfile):
                    os.remove(self.pidfile)
            else:
                print str(err)
                sys.exit(1)

    def restart(self):
        """
        Restart the daemon
        """
        self.stop()
        self.start()

    def run(self):
        """
        You should override this method when you subclass Daemon. It will be called after the process has been
        daemonized by start() or restart().
        """

@@ -19,440 +19,196 @@
 hon%0A
-%22%22%22%0AFound at:%0Ahttp://www.jejik.com/articles/2007/02/a_simple_unix_linux_daemon_in_python/%0A%0A--%3E mentioned in the comments below the code%0A#5 Anonymous Coward Posted on 2008-11-26@16:37%0AWhat is the license on this code? Can I have it under GPL?%0A#6 Sander Marechal (http://www.jejik.com) Posted on 2008-11-26@16:40%0A@Anonymous Coward This is really basic stuff and not very original. It's Public Domain, so do with it as you please.%0A%0A%22%22%22
+%0A##%0A# Copyright 2007 Sander Marechal (http://www.jejik.com)%0A# Released as Public Domain%0A# Retrieved from:%0A# http://www.jejik.com/articles/2007/02/a_simple_unix_linux_daemon_in_python/%0A#%0A##
 %0Aimp
@@ -1987,16 +1987,17 @@
 pidfile,
+ 
 'w+').wr
@@ -2244,32 +2244,33 @@
 le(self.pidfile,
+ 
 'r')%0A           
@@ -2767,16 +2767,17 @@
 pidfile,
+ 
 'r')%0A   
@@ -3801,20 +3801,33 @@
 tart().%0A        %22%22%22%0A
+        pass%0A

revert reverted changes to daemon.py