#!/usr/bin/env python

###
# Copyright (c) 2005, Jeremiah Fincher
# Copyright (c) 2009, James McCoy
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#   * Redistributions of source code must retain the above copyright notice,
#     this list of conditions, and the following disclaimer.
#   * Redistributions in binary form must reproduce the above copyright notice,
#     this list of conditions, and the following disclaimer in the
#     documentation and/or other materials provided with the distribution.
#   * Neither the name of the author of this software nor the name of
#     contributors to this software may be used to endorse or promote products
#     derived from this software without specific prior written consent.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
###

VERBOSE = False

def readPid(filename):
    fd = open(filename)
    try:
        return int(fd.read().strip())
    finally:
        fd.close()

def isAlive(pid):
    try:
        os.kill(pid, 0)
        return True
    except OSError:
        return False

def debug(s):
    if VERBOSE:
        if not s.endswith(os.linesep):
            s += os.linesep
        sys.stdout.write(s)

if __name__ == '__main__':
    # XXX I wanted this for conf.version, but this will create directories. We
    # really need to refactor conf so it either doesn't create directories, or
    # so that static information (like the version) can be imported from
    # somewhere else.
    # import supybot.conf as conf
    import os
    import sys
    import optparse
    import subprocess

    parser = optparse.OptionParser(usage='Usage: %prog [options]')
    parser.add_option('', '--verbose', action='store_true',
                      help='Makes output verbose.')
    parser.add_option('', '--botdir',
                      help='Determines what directory the bot resides in and '
                      'should be started from.')
    parser.add_option('', '--pidfile',
                      help='Determines what file to look in for the pid of '
                      'the running bot.  This should be relative to the '
                      'given bot directory. Note that for this to actually '
                      'work, you have to make a matching entry in the '
                      'supybot.pidFile config in the supybot registry.')
    parser.add_option('', '--supybot', default='supybot',
                      help='Determines where the supybot executable is '
                      'located.  If not given, assumes that supybot is '
                      'in $PATH.')
    parser.add_option('', '--conffile',
                      help='Determines what configuration file should be '
                      'given to the supybot executable when (re)starting the '
                      'bot.')

    (options, args) = parser.parse_args()
    VERBOSE = options.verbose

    if args:
        parser.error('Extra arguments given.')
    if not options.botdir:
        parser.error('No botdir given.')
    if not options.pidfile:
        parser.error('No pidfile given.')
    if not options.conffile:
        parser.error('No conffile given.')

    os.chdir(options.botdir)
    open(options.pidfile, 'a').close() 

    pid = None
    try:
        pid = readPid(options.pidfile)
        debug('Found pidFile with proper pid contents of %s' % pid)
    except ValueError as e:
        foundBot = False

    if pid is not None:
        foundBot = isAlive(pid)
        if foundBot:
            debug('Pid %s is alive and belongs to us.' % pid)
        else:
            debug('Pid %s is not the bot.' % pid)

    if not foundBot:
        # First, we check if the pidfile is writable.  If not, supybot will just exit,
        # so we go ahead and refuse to start it.
        try:
            open(options.pidfile, 'r+')
        except EnvironmentError as e:
            debug('pidfile (%s) is not writable: %s' % (options.pidfile, e))
            sys.exit(-1)
        debug('Bot not found, starting.')
        cmdline = [options.supybot, '--daemon', options.conffile]
        inst = subprocess.Popen(cmdline, close_fds=True,
                                stderr=subprocess.STDOUT,
                                stdin=None, stdout=subprocess.PIPE)
        debug('Output from supybot: %r' % inst.stdout.read())
        ret = inst.wait()
        debug('Bot started, command line %r returned %s.' % (' '.join(cmdline),
                                                             ret))
        sys.exit(ret)
    else:
        sys.exit(0)

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