synarere.py

   1 #!/usr/bin/env python
   2 #
   3 # synarere -- a highly modular and stable IRC bot.
   4 # Copyright (C) 2010 Michael Rodriguez.
   5 # Rights to this code are documented in docs/LICENSE.
   6
   7 '''Main program. This does basic routines, and calls core functions.'''
   8
   9 # Import required Python modules.
  10 import getopt, os, signal, sys
  11
  12 # Import required core modules.
  13 from core import module, irc, logger, io, var, confparse, command
  14
  15 # Import required core function.
  16 from core import shutdown
  17
  18 def ctcp_version(conn, (nick, user, host), message):
  19     '''Handle VERSION requests.'''
  20
  21     conn.sendq.appendleft('NOTICE %s :\001VERSION synarere-%s\001' % (nick, var.version))
  22     return
  23
  24 def ctcp_ping(conn, (nick, user, host), message):
  25     '''Handle PING requests.'''
  26
  27     conn.sendq.appendleft('NOTICE %s :\001PING %s\001' % (nick, message))
  28     return
  29
  30 def on_sighup(signum, frame):
  31     '''Handle SIGHUP. This will rehash the configuration.'''
  32
  33     var.conf.rehash(True)
  34
  35 def on_sigint(signum, frame):
  36     '''Handle SIGINT. This will exit gracefully.'''
  37
  38     shutdown(signum, 'Caught SIGINT (terminal interrupt)')
  39
  40 def on_sigterm(signum, frame):
  41     '''Handle SIGTERM. This will exit gracefully.'''
  42
  43     shutdown(signum, 'Caught SIGTERM')
  44
  45 def print_clo_help():
  46     '''Output command line options and their meanings.'''
  47
  48     print '-c (--config) <config>: Specify the configuration file to use.'
  49     print '-h (--help): Output this message.'
  50     print '-n (--nofork): Do not fork into the background (will output log messages)'
  51     print '-p (--pydebug): Start in the Python Debugger.'
  52     print '-v (--version): Output version information.'
  53
  54 def main(argv=sys.argv[1:]):
  55     '''Our entry point.'''
  56
  57     # Are we root?
  58     if os.geteuid() == 0:
  59         print >> sys.stderr, 'synarere: will not run as root for security reasons'
  60         sys.exit(0)
  61
  62     # Parse command line options and parameter list.
  63     try:
  64         opts, args = getopt.getopt(argv, 'c:hnpv', ['config=', 'help', 'nofork', 'pydebug', 'version'])
  65     except getopt.GetoptError, err:
  66         print >> sys.stderr, '%s\n' % err
  67         print_clo_help()
  68         sys.exit(os.EX_USAGE)
  69
  70     for opt, arg in opts:
  71         if opt in ('-c', '--config'):
  72             var.config_file = arg
  73         elif opt in ('-h', '--help'):
  74             print_clo_help()
  75             sys.exit(os.EX_OK)
  76         elif opt in ('-n', '--nofork'):
  77             var.fork = False
  78         elif opt in ('-p', '--pydebug'):
  79             import pdb
  80             pdb.set_trace()
  81         elif opt in ('-v', '--version'):
  82             print 'synarere: version %s' % var.version
  83             sys.exit(os.EX_OK)
  84
  85     # Attach signals to handlers.
  86     signal.signal(signal.SIGHUP, on_sighup)
  87     signal.signal(signal.SIGINT, on_sigint)
  88     signal.signal(signal.SIGTERM, on_sigterm)
  89     signal.signal(signal.SIGPIPE, signal.SIG_IGN)
  90     signal.signal(signal.SIGALRM, signal.SIG_IGN)
  91     signal.signal(signal.SIGCHLD, signal.SIG_IGN)
  92     signal.signal(signal.SIGWINCH, signal.SIG_IGN)
  93     signal.signal(signal.SIGTTIN, signal.SIG_IGN)
  94     signal.signal(signal.SIGTTOU, signal.SIG_IGN)
  95     signal.signal(signal.SIGTSTP, signal.SIG_IGN)
  96
  97     print 'synarere: version %s' % var.version
  98
  99     # Initialize the configuration parser.
 100     try:
 101         var.conf = confparse.ConfigParser(var.config_file)
 102     except confparse.Exception, errstr:
 103         print >> sys.stderr, 'synarere: configuration error for %s: %s' % (var.config_file, errstr)
 104         sys.exit(os.EX_CONFIG)
 105
 106     # Check to see if we are already running.
 107     try:
 108         pid_file = open(var.conf.get('options', 'pidfile')[0], 'r')
 109
 110         try:
 111             pid = pid_file.read()
 112
 113             if pid:
 114                 pid = int(pid)
 115
 116                 try:
 117                     os.kill(pid, 0)
 118                 except OSError:
 119                     pass
 120
 121                 print >> sys.stderr, 'synarere: an instance is already running'
 122                 sys.exit(os.EX_SOFTWARE)
 123         finally:
 124             pid_file.close()
 125     except IOError:
 126         pass
 127
 128     # Fork into the background.
 129     if var.fork:
 130         try:
 131             pid = os.fork()
 132         except OSError, e:
 133             return (e.errno, e.strerror)
 134
 135         # This is the child process.
 136         if pid == 0:
 137             os.setsid()
 138
 139             # Now the child fork()'s a child in order to prevent acquisition
 140             # of a controlling terminal.
 141             try:
 142                 pid = os.fork()
 143             except OSError, e:
 144                 return (e.errno, e.strerror)
 145
 146             # This is the second child process.
 147             if pid == 0:
 148                 os.chdir(os.getcwd())
 149                 os.umask(0)
 150
 151             # This is the first child.
 152             else:
 153                 print 'synarere: pid', pid
 154                 print 'synarere: running in background mode from:', os.getcwd()
 155                 os._exit(0)
 156         else:
 157             os._exit(0)
 158
 159         # Try to write the PID file.
 160         try:
 161             pid_file = open(var.conf.get('options', 'pidfile')[0], 'w')
 162             pid_file.write(str(os.getpid()))
 163             pid_file.close()
 164         except IOError, e:
 165             print >> sys.stderr, 'synarere: unable to write pid file:', os.strerror(e.args[0])
 166
 167         # Try to close all open file descriptors.
 168         # If we cant find the max number, just close the first 256.
 169         try:
 170             maxfd = os.sysconf('SC_OPEN_MAX')
 171         except (AttributeError, ValueError):
 172             maxfd = 256
 173
 174         for fd in range(0, maxfd):
 175             try:
 176                 os.close(fd)
 177             except OSError:
 178                 pass
 179
 180         # Redirect the standard file descriptors to /dev/null.
 181         os.open('/dev/null', os.O_RDONLY)
 182         os.open('/dev/null', os.O_RDWR)
 183         os.open('/dev/null', os.O_RDWR)
 184     else:
 185         print 'synarere: pid', os.getpid()
 186         print 'synarere: running in foreground mode from:', os.getcwd()
 187
 188     # Initialize the logger.
 189     logger.init()
 190
 191     # These have to be in the main file.
 192     command.add('VERSION', ctcp_version, command.ctcp)
 193     command.add('PING', ctcp_ping, command.ctcp)
 194
 195     # Load all modules listed in the configuration.
 196     module.load_all()
 197
 198     # Connect to all IRC networks.
 199     irc.connect_to_all()
 200
 201     # Start the loop.
 202     io.io()
 203
 204     # This should NEVER happen.
 205     shutdown(os.EX_SOFTWARE, 'Main loop exited (?)')
 206
 207 if __name__ == '__main__':
 208     main()