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import os
import sys

if os.name == 'posix':

    def become_daemon(ourHomeDir='.',outLog='/dev/null',errLog='/dev/null'):
        """
        Robustly turn us into a UNIX daemon, running in ourHomeDir.
        Modelled after the original code of this module and some
        sample code from the net.
        """

        # first fork
        try:
            if os.fork() > 0:
                sys.exit(0)     # kill off parent
        except OSError, e:
            sys.stderr.write("fork #1 failed: (%d) %s
" % (e.errno, e.strerror))
            sys.exit(1)
        os.setsid()
        os.chdir(ourHomeDir)
        os.umask(0)
        # second fork
        try:
            if os.fork() > 0:
                sys.exit(0)
        except OSError, e:
            sys.stderr.write("fork #2 failed: (%d) %s
" % (e.errno, e.strerror))
            sys.exit(1)

        si = open('/dev/null', 'r')
        so = open(outLog, 'a+', 0)
        se = open(errLog, 'a+', 0)
        os.dup2(si.fileno(), sys.stdin.fileno())
        os.dup2(so.fileno(), sys.stdout.fileno())
        os.dup2(se.fileno(), sys.stderr.fileno())

else:

    def become_daemon(ourHomeDir='.',outLog=None,errLog=None):
        """
        If we are not running under a POSIX system, just simulate
        the daemon mode by doing redirections and directory changeing
        """

        os.chdir(ourHomeDir)
        os.umask(0)
        sys.stdin.close()
        sys.stdout.close()
        sys.stderr.close()
        if errLog and outLog:
            sys.stderr=open (errLog, 'a', 0)
            sys.stdout=open (outLog, 'a', 0)
        elif errLog:
            sys.stderr=open (errLog, 'a', 0)
            sys.stdout=NullDevice ()
        elif outLog:
            sys.stdout=open (outLog, 'a', 0)
            sys.stderr=NullDevice ()
        else:
            sys.stdout = NullDevice()
            sys.stderr = NullDevice()

    class NullDevice:
        """
        A substitute for stdout and stderr that writes to nowhere.
        This is a substitute for /dev/null
        """
    
        def write(self, s):
            pass

def main():
    from flup.server.scgi_fork import WSGIServer
    from django.core.handlers.wsgi import WSGIHandler

    import getopt

    (opts, args) = getopt.getopt(sys.argv[1:], 'f:s:h:p:',
        ['settings=','socket=','host=','port=',
         'minspare=', 'maxspare=', 'maxchildren=',
         'daemon', 'etclog=', 'errorlog=', 'workdir=',
         'projects='])
    
    socket = None
    host = None
    port = None

    minspare = 1
    maxspare = 5
    maxchildren = 50

    daemon = None
    workdir = '.'
    etclog = '/dev/null'
    errorlog = '/dev/null'

    projects = []

    for (o, v) in opts:
        if o in ('-s', '--socket'):
            socket = v
        elif o in ('-h', '--host'):
            host = v
        elif o in ('-p', '--port'):
            port = int(v)
        elif o in ('-f', '--settings'):
            os.environ['DJANGO_SETTINGS_MODULE'] = v
        elif o in ('--minspare',):
            minspare = int(v)
        elif o in ('--maxspare',):
            maxspare = int(v)
        elif o in ('--maxchildren',):
            maxchildren = int(v)
        elif o in ('--daemon',):
            daemon = 1
        elif o in ('--errorlog',):
            errorlog = v
        elif o in ('--etclog',):
            etclog = v
        elif o in ('--workdir',):
            workdir = v
        elif o in ('--projects',):
            projects.append(v)
    
    # add projects to path
    for p in projects:
        if p not in sys.path:
            sys.path.insert(0, p)

    # if we should run as a daemon, use the above function to turn us
    # into one reliably. This should correctly detach from the tty.
    if daemon:
        become_daemon(ourHomeDir=workdir,
            outLog=etclog, errLog=errorlog)

    if socket and not host and not port:
        WSGIServer(WSGIHandler(), minSpare=minspare, maxSpare=maxspare, maxChildren=maxchildren, bindAddress=socket).run()
    elif not socket and host and port:
        WSGIServer(WSGIHandler(), minSpare=minspare, maxSpare=maxspare, maxChildren=maxchildren, bindAddress=(host, port)).run()
    else:
        print "usage: django-scgi.py [--settings=<settingsmodule>] --socket=<socketname>"
        print "   or: django-scgi.py [--settings=<settingsmodule>] --host==<hostname> --port=<portnumber>"
        print
        print "   additional options are:"
        print "      --minspare=<minimum number of spare processes, default 1>"
        print "      --maxspare=<maximum number of spare processes, default 5>"
        print "      --maxchildren=<maximum number of child processes, default 50>"
        print
        print "      --daemon"
        print "      --etclog=<path for stdout log, default /dev/null>"
        print "      --errorlog=<path for stderr log, default /dev/null>"
        print "      --workdir=<path for working directory, default .>"
        print
        print "      --projects=<path to add to sys.path>"

if __name__ == '__main__':

    # first patch our own version of socketpair into the sockets module
    # if we don't have it already (comes with Python 2.4)

    import socket
    if not hasattr(socket, 'socketpair'):
        import eunuchs.socketpair

        def socketpair():
            (p,c) = eunuchs.socketpair.socketpair()
            (pp,cc) = (socket.fromfd(p,1,1), socket.fromfd(c,1,1))
            os.close(c)
            os.close(p)
            return (pp,cc)

        socket.socketpair = socketpair

    main()