root/trunk/common.py

#
# Copyright (C) 2008 Red Hat, Inc.
# Author: Andreas Thienemann <athienem@redhat.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Library General Public License as published by
# the Free Software Foundation; version 2 only
#
# 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 Library General Public License for more details.
#
# You should have received a copy of the GNU Library General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
# Copyright 2004, 2005 Red Hat, Inc.
#
# AUTHOR: Andreas Thienemann <athienem@redhat.com>
#

import os, sys

def daemonize (stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'):
    '''Daemonize the process'''
    try:
        pid = os.fork()
        if pid > 0:
            sys.exit(0)   # Exit first parent.
    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.umask(0)
    os.setsid()
 
    # Do second fork.
    try:
        pid = os.fork()
        if pid > 0:
            sys.exit(0)   # Exit second parent.
    except OSError, e:
        sys.stderr.write ("fork #2 failed: (%d) %s\n" % (e.errno, e.strerror) )
        sys.exit(1)
 
    # Now I am a daemon!
 
    # Redirect standard file descriptors.
    si = open(stdin, 'r')
    so = open(stdout, 'a+')
    se = open(stderr, 'a+', 0)
    os.dup2(si.fileno(), sys.stdin.fileno())
    os.dup2(so.fileno(), sys.stdout.fileno())
    os.dup2(se.fileno(), sys.stderr.fileno())


#convert string to hex
def toHex(s):
    lst = []
    for ch in s:
        hv = hex(ord(ch)).replace('0x', '')
        if len(hv) == 1:
            hv = '0'+hv
        lst.append(hv)
    
    return reduce(lambda x,y:x+y, lst)

#convert hex repr to string
def toStr(s):
    return s and chr(atoi(s[:2], base=16)) + toStr(s[2:]) or ''