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# Source code for gateone

    #!/usr/bin/env python
    # -*- coding: utf-8 -*-
    #
    #       Copyright 2011 Liftoff Software Corporation
    #
    # For license information see LICENSE.txt

    # TODO:
    # * Write init scripts to stop/start/restart Gate One safely.  Also make sure that .deb and .rpm packages safely restart Gate One without impacting running sessions.  The setup.py should also attempt to minify the .css and .js files.
    # * Write a permissions check function so we don't have to repeat ourselves all over the place inside of main()
    # * Make it so that the session_dir gets cleaned up.  Will require some logic in regards dtach detection.

    # Meta
    __version__ = '1.1'
    __license__ = "AGPLv3 or Proprietary (see LICENSE.txt)"
    __version_info__ = (1, 1)
    __author__ = 'Dan McDougall <daniel.mcdougall@liftoffsoftware.com>'

    # NOTE: Docstring includes reStructuredText markup for use with Sphinx.
    __doc__ = '''\
    .. _gateone.py:

    Gate One
    ========
    Gate One is a web-based terminal emulator written in Python using the Tornado
    web framework.  This module runs the primary daemon process and acts as a
    central controller for all running terminals and terminal programs.  It supports
    numerous configuration options and can also be called with the --kill switch
    to kill all running terminal programs (if using dtach--otherwise they die on
    their own when gateone.py is stopped).

    Dependencies
    ------------
    Gate One requires Python 2.6+ but runs best with Python 2.7+.  It also depends
    on the following 3rd party Python modules:

     * `Tornado <http://www.tornadoweb.org/>`_ 2.2+ - A non-blocking web server framework that powers FriendFeed.

    The following modules are optional and can provide Gate One with additional
    functionality:

     * `pyOpenSSL <https://launchpad.net/pyopenssl>`_ 0.10+ - An OpenSSL module/wrapper for Python.  Only used to generate self-signed SSL keys and certificates.  If pyOpenSSL isn't available Gate One will fall back to using the 'openssl' command to generate self-signed certificates.
     * `kerberos <http://pypi.python.org/pypi/kerberos>`_ 1.0+ - A high-level Kerberos interface for Python.  Only necessary if you plan to use the Kerberos authentication module.
     * `python-pam <http://packages.debian.org/lenny/python-pam>`_ 0.4.2+ - A Python module for interacting with PAM (the Pluggable Authentication Module present on nearly every Unix).  Only necessary if you plan to use PAM authentication.

    With the exception of python-pam, both the required and optional modules can usually be installed via one of these commands:

        .. ansi-block::

            \x1b[1;34muser\x1b[0m@modern-host\x1b[1;34m:~ $\x1b[0m sudo pip install tornado pyopenssl kerberos

    ...or:

        .. ansi-block::

            \x1b[1;34muser\x1b[0m@legacy-host\x1b[1;34m:~ $\x1b[0m sudo easy_install tornado pyopenssl kerberos

    .. note:: The use of pip is recommended.  See http://www.pip-installer.org/en/latest/installing.html if you don't have it.

    The python-pam module is available in most Linux distribution repositories.  Simply executing one of the following should take care of it:

        .. ansi-block::

            \x1b[1;34muser\x1b[0m@debian-or-ubuntu-host\x1b[1;34m:~ $\x1b[0m sudo apt-get install python-pam

        .. ansi-block::

            \x1b[1;34muser\x1b[0m@redhat-host\x1b[1;34m:~ $\x1b[0m sudo yum install python-pam

        .. ansi-block::

            \x1b[1;34muser\x1b[0m@gentoo-host\x1b[1;34m:~ $\x1b[0m sudo emerge python-pam

        .. ansi-block::

            \x1b[1;34muser\x1b[0m@suse-host\x1b[1;34m:~ $\x1b[0m sudo yast -i python-pam

    Settings
    --------
    All of Gate One's configurable options can be controlled either via command line
    switches or by settings in the server.conf file (they match up 1-to-1).  If no
    server.conf exists one will be created using defaults (i.e. when Gate One is run
    for the first time).  Settings in the server.conf file use the following format::

        <setting> = <value>

    Here's an example::

        address = "127.0.0.1;::1;10.1.1.4" # Strings are surrounded by quotes
        port = 443 # Numbers don't need quotes

    There are a few important differences between the configuration file and
    command line switches in regards to boolean values (True/False).  A switch such
    as --debug evaluates to "debug = True" and this is exactly how it would be
    configured in server.conf::

        debug = True # Booleans don't need quotes either

    .. note:: The following values in server.conf are case sensitive: True, False and None (and should not be placed in quotes).

    Running gateone.py with the --help switch will print the usage information as
    well as descriptions of what each configurable option does:

    .. ansi-block::

        \x1b[1;31mroot\x1b[0m@host\x1b[1;34m:~ $\x1b[0m ./gateone.py --help
        Usage: ./gateone.py [OPTIONS]

        Options:
          --help                           show this help information
          --log_file_max_size              max size of log files before rollover
          --log_file_num_backups           number of log files to keep
          --log_file_prefix=PATH           Path prefix for log files. Note that if you are running multiple tornado processes, log_file_prefix must be different for each of them (e.g. include the port number)
          --log_to_stderr                  Send log output to stderr (colorized if possible). By default use stderr if --log_file_prefix is not set and no other logging is configured.
          --logging=debug|info|warning|error|none Set the Python log level. If 'none', tornado won't touch the logging configuration.
          --address                        Run on the given address.  Default is all addresses (IPv6 included).  Multiple address can be specified using a semicolon as a separator (e.g. '127.0.0.1;::1;10.1.1.100').
          --auth                           Authentication method to use.  Valid options are: none, api, google, kerberos, pam
          --certificate                    Path to the SSL certificate.  Will be auto-generated if none is provided.
          --command                        Run the given command when a user connects (e.g. '/bin/login').
          --config                         Path to the config file.  Default: /opt/gateone/server.conf
          --cookie_secret                  Use the given 45-character string for cookie encryption.
          --debug                          Enable debugging features such as auto-restarting when files are modified.
          --disable_ssl                    If enabled, Gate One will run without SSL (generally not a good idea).
          --dtach                          Wrap terminals with dtach. Allows sessions to be resumed even if Gate One is stopped and started (which is a sweet feature).
          --embedded                       Doesn't do anything (yet).
          --enable_unix_socket             Enable Unix socket support use_unix_sockets (if --enable_unix_socket=True).
          --https_redirect                 If enabled, a separate listener will be started on port 80 that redirects users to the configured port using HTTPS.
          --js_init                        A JavaScript object (string) that will be used when running GateOne.init() inside index.html.  Example: --js_init="{scheme: 'white'}" would result in GateOne.init({scheme: 'white'})
          --keyfile                        Path to the SSL keyfile.  Will be auto-generated if none is provided.
          --kill                           Kill any running Gate One terminal processes including dtach'd processes.
          --locale                         The locale (e.g. pt_PT) Gate One should use for translations.  If not provided, will default to $LANG (which is 'en_US' in your current shell), or en_US if not set.
          --new_api_key                    Generate a new API key that an external application can use to embed Gate One.
          --origins                        A semicolon-separated list of origins you wish to allow access to your Gate One server over the WebSocket.  This value must contain the hostnames and FQDNs (e.g. https://foo;https://foo.bar;) users will use to connect to your Gate One server as well as the hostnames/FQDNs of any sites that will be embedding Gate One. Here's the default on your system: 'https://localhost;https://yourhostname'. Alternatively, '*' may be  specified to allow access from anywhere.
          --pam_realm                      Basic auth REALM to display when authenticating clients.  Default: hostname.  Only relevant if PAM authentication is enabled.
          --pam_service                    PAM service to use.  Defaults to 'login'. Only relevant if PAM authentication is enabled.
          --pid_file                       Path of the pid file.   Default: /var/run/gateone.pid
          --port                           Run on the given port.
          --session_dir                    Path to the location where session information will be stored.
          --session_logging                If enabled, logs of user sessions will be saved in <user_dir>/<user>/logs.  Default: Enabled
          --session_timeout                Amount of time that a session should be kept alive after the client has logged out.  Accepts <num>X where X could be one of s, m, h, or d for seconds, minutes, hours, and days.  Default is '5d' (5 days).
          --sso_realm                      Kerberos REALM (aka DOMAIN) to use when authenticating clients. Only relevant if Kerberos authentication is enabled.
          --sso_service                    Kerberos service (aka application) to use. Defaults to HTTP. Only relevant if Kerberos authentication is enabled.
          --syslog_facility                Syslog facility to use when logging to syslog (if syslog_session_logging is enabled).  Must be one of: auth, cron, daemon, kern, local0, local1, local2, local3, local4, local5, local6, local7, lpr, mail, news, syslog, user, uucp.  Default: daemon
          --syslog_host                    Remote host to send syslog messages to if syslog_logging is enabled.  Default: None (log to the local syslog daemon directly).  NOTE:  This setting is required on platforms that don't include Python's syslog module.
          --syslog_session_logging         If enabled, logs of user sessions will be written to syslog.
          --unix_socket_path               Run on the given socket file.  Default: /var/run/gateone.sock
          --url_prefix                     An optional prefix to place before all Gate One URLs. e.g. '/gateone/'.  Use this if Gate One will be running behind a reverse proxy where you want it to be located at some sub-URL path.
          --user_dir                       Path to the location where user files will be stored.

    .. note:: Some of these options (e.g. log_file_prefix) are inherent to the Tornado framework.  You won't find them anywhere in gateone.py.

    File Paths
    ----------
    Gate One stores its files, temporary session information, and persistent user
    data in the following locations (Note: Many of these are configurable):

    ================= ==================================================================================
    File/Directory      Description
    ================= ==================================================================================
    authpam.py        Contains the PAM authentication Mixin used by auth.py.
    auth.py           Authentication classes.
    certificate.pem   The default certificate Gate One will use in SSL communications.
    docs/             Gate One's documentation.
    gateone.py        Gate One's primary executable/script. Also, the file containing this documentation
    i18n/             Gate One's internationalization (i18n) support and locale/translation files.
    keyfile.pem       The default private key used with SSL communications.
    logviewer.py      A utility to view Gate One session logs.
    plugins/          Plugins go here in the form of ./plugins/<plugin name>/<plugin files|directories>
    remote_syslog.py  A module that supports sending syslog messages over UDP to a remote syslog host.
    server.conf       Gate One's configuration file.
    sso.py            A Kerberos Single Sign-on module for Tornado (used by auth.py)
    static/           Non-dynamic files that get served to clients (e.g. gateone.js, gateone.css, etc).
    templates/        Tornado template files such as index.html.
    terminal.py       A Pure Python terminal emulator module.
    termio.py         Terminal input/output control module.
    tests/            Various scripts and tools to test Gate One's functionality.
    utils.py          Various supporting functions.
    users/            Persistent user data in the form of ./users/<username>/<user-specific files>
    users/<user>/logs This is where session logs get stored if session_logging is set.
    /tmp/gateone      Temporary session data in the form of /tmp/gateone/<session ID>/<files>
    ================= ==================================================================================

    Running
    -------
    Executing Gate One is as simple as:

    .. ansi-block::

        \x1b[1;31mroot\x1b[0m@host\x1b[1;34m:~ $\x1b[0m ./gateone.py

    .. note:: By default Gate One will run on port 443 which requires root on most systems.  Use `--port=(something higher than 1024)` for non-root users.

    Plugins
    -------
    Gate One includes support for any combination of the following types of plugins:

     * Python
     * JavaScript
     * CSS

    Python plugins can integrate with Gate One in three ways:

     * Adding or overriding tornado.web.RequestHandlers (with a given regex).
     * Adding or overriding methods (aka "commands") in TerminalWebSocket.
     * Adding special plugin-specific escape sequence handlers (see the plugin development documentation for details on what/how these are/work).

    JavaScript plugins will be added to the <body> tag of Gate One's base index.html
    template by way of a single file (`{{gateone_js}}` below) that is the
    concatenation of all plugins' JS templates:

    .. code-block:: html

        <script type="text/javascript" src="{{gateone_js}}"></script>

    CSS plugins are similar to JavaScript but instead of being appended to the
    <body> they are added to the <head> by way of a WebSocket download and some
    fancy JavaScript inside of gateone.js:

    .. code-block:: javascript

        CSSPluginAction: function(url) {
            // Loads the CSS for a given plugin by adding a <link> tag to the <head>
            var queries = url.split('?')[1].split('&'), // So we can parse out the plugin name and the template
                plugin = queries[0].split('=')[1],
                file = queries[1].split('=')[1].split('.')[0];
            // The /cssrender method needs the prefix and the container
            url = url + '&container=' + GateOne.prefs.goDiv.substring(1);
            url = url + '&prefix=' + GateOne.prefs.prefix;
            url = GateOne.prefs.url + url.substring(1);
            GateOne.Utils.loadCSS(url, plugin+'_'+file);
        }

    There are also hooks throughout Gate One's code for plugins to add or override
    Gate One's functionality.  Documentation on how to write plugins can be found in
    the Plugin Development docs.  From the perspective of gateone.py, it performs
    the following tasks in relation to plugins:

     * Imports Python plugins and connects their hooks.
     * Creates symbolic links inside ./static/ that point to each plugin's respective /static/ directory and serves them to clients.
     * Serves the index.html that includes plugins' respective .js and .css files.

    Class Docstrings
    ================
    '''

    # Standard library modules
    import os
    import sys
    import logging
    import time
    import socket
    import pty
    import pwd, grp
    import atexit
    import ssl
    from functools import partial, wraps
    from datetime import datetime, timedelta

    # Tornado modules (yeah, we use all this stuff)
    try:
        import tornado.httpserver
        import tornado.ioloop
        import tornado.options
        import tornado.web
        import tornado.auth
        import tornado.template
        import tornado.netutil
        from tornado.websocket import WebSocketHandler
        from tornado.escape import json_decode
        from tornado.options import define, options
        from tornado import locale
        from tornado import version as tornado_version
        from tornado import version_info as tornado_version_info
    except ImportError:
        print("\x1b[31;1mERROR:\x1b[0m Gate One requires the Tornado framework.  "
              "You probably want to run something like, \x1b[1m'pip install "
              "--upgrade tornado'\x1b[0m.")
        sys.exit(1)

    if tornado_version_info[0] < 2 and tornado_version_info[1] < 2:
        print("\x1b[31;1mERROR:\x1b[0m Gate One requires version 2.2+ of the "
                "Tornado framework.  The installed version of Tornado is version "
                "%s." % tornado_version)
        sys.exit(1)

    # We want this turned on right away
    tornado.options.enable_pretty_logging()

    # Our own modules
    import termio, terminal
    from auth import NullAuthHandler, KerberosAuthHandler, GoogleAuthHandler
    from auth import PAMAuthHandler
    from utils import str2bool, generate_session_id, cmd_var_swap, mkdir_p
    from utils import gen_self_signed_ssl, killall, get_plugins, load_plugins
    from utils import create_plugin_links, merge_handlers, none_fix, short_hash
    from utils import convert_to_timedelta, kill_dtached_proc, FACILITIES, which
    from utils import process_opt_esc_sequence, create_data_uri, MimeTypeFail
    from utils import string_to_syslog_facility, fallback_bell, json_encode
    from utils import write_pid, read_pid, remove_pid, drop_privileges
    from utils import recursive_chown, ChownError

    # Setup the locale functions before anything else
    locale.set_default_locale('en_US')
    user_locale = None # Replaced with the actual user locale object in __main__
    def _(string):
        """
        Wraps user_locale.translate so we can .encode('UTF-8') when writing to
        stdout.  This function will get overridden by the regular translate()
        function in __main__
        """
        if user_locale:
            return user_locale.translate(string).encode('UTF-8')
        else:
            return string.encode('UTF-8')

    # Globals
    SESSIONS = {} # We store the crux of most session info here
    CMD = None # Will be overwritten by options.command
    TIMEOUT = timedelta(days=5) # Gets overridden by options.session_timeout
    WATCHER = None # Holds the reference to our timeout_sessions periodic callback
    CLEANER = None # The reference to our session logs cleanup periodic callback
    GATEONE_DIR = os.path.dirname(os.path.abspath(__file__))
    PLUGINS = get_plugins(os.path.join(GATEONE_DIR, 'plugins'))
    PLUGIN_WS_CMDS = {} # Gives plugins the ability to extend/enhance TerminalWebSocket
    PLUGIN_HOOKS = {} # Gives plugins the ability to hook into various things.
    PLUGIN_AUTH_HOOKS = [] # For plugins to register functions to be called after a
                           # user successfully authenticates
    # Gate One registers a handler for for terminal.py's CALLBACK_OPT special escape
    # sequence callback.  Whenever this escape sequence is encountered, Gate One
    # will parse the sequence's contained characters looking for the following
    # format:
    #   <plugin name>|<whatever>
    # The <whatever> part will be passed to any plugin matching <plugin name> if the
    # plugin has 'Escape': <function> registered in its hooks.
    PLUGIN_ESC_HANDLERS = {}
    # This is used to store plugin terminal hooks that are called when a new
    # terminal is created (so a plugin could override/attach callbacks to the
    # multiplex or terminal emulator instances).
    PLUGIN_TERM_HOOKS = {}

    # Secondary locale setup
    locale_dir = os.path.join(GATEONE_DIR, 'i18n')
    locale.load_gettext_translations(locale_dir, 'gateone')
    # NOTE: The locale gets set in __main__

    # A HUGE thank you to Micah Elliott (http://MicahElliott.com) for posting these
    # values here: https://gist.github.com/719710
    # This gets used by StyleHandler to generate the CSS that supports 256-colors:
    COLORS_256 = {
        # 8-color equivalents:
         0: "000000",
         1: "800000",
         2: "008000",
         3: "808000",
         4: "000080",
         5: "800080",
         6: "008080",
         7: "c0c0c0",
        # "Bright" (16-color) equivalents:
         8: "808080",
         9: "ff0000",
        10: "00ff00",
        11: "ffff00",
        12: "0000ff",
        13: "ff00ff",
        14: "00ffff",
        15: "ffffff",
        # The rest of the 256-colors:
        16: "000000",
        17: "00005f",
        18: "000087",
        19: "0000af",
        20: "0000d7",
        21: "0000ff",
        22: "005f00",
        23: "005f5f",
        24: "005f87",
        25: "005faf",
        26: "005fd7",
        27: "005fff",
        28: "008700",
        29: "00875f",
        30: "008787",
        31: "0087af",
        32: "0087d7",
        33: "0087ff",
        34: "00af00",
        35: "00af5f",
        36: "00af87",
        37: "00afaf",
        38: "00afd7",
        39: "00afff",
        40: "00d700",
        41: "00d75f",
        42: "00d787",
        43: "00d7af",
        44: "00d7d7",
        45: "00d7ff",
        46: "00ff00",
        47: "00ff5f",
        48: "00ff87",
        49: "00ffaf",
        50: "00ffd7",
        51: "00ffff",
        52: "5f0000",
        53: "5f005f",
        54: "5f0087",
        55: "5f00af",
        56: "5f00d7",
        57: "5f00ff",
        58: "5f5f00",
        59: "5f5f5f",
        60: "5f5f87",
        61: "5f5faf",
        62: "5f5fd7",
        63: "5f5fff",
        64: "5f8700",
        65: "5f875f",
        66: "5f8787",
        67: "5f87af",
        68: "5f87d7",
        69: "5f87ff",
        70: "5faf00",
        71: "5faf5f",
        72: "5faf87",
        73: "5fafaf",
        74: "5fafd7",
        75: "5fafff",
        76: "5fd700",
        77: "5fd75f",
        78: "5fd787",
        79: "5fd7af",
        80: "5fd7d7",
        81: "5fd7ff",
        82: "5fff00",
        83: "5fff5f",
        84: "5fff87",
        85: "5fffaf",
        86: "5fffd7",
        87: "5fffff",
        88: "870000",
        89: "87005f",
        90: "870087",
        91: "8700af",
        92: "8700d7",
        93: "8700ff",
        94: "875f00",
        95: "875f5f",
        96: "875f87",
        97: "875faf",
        98: "875fd7",
        99: "875fff",
        100: "878700",
        101: "87875f",
        102: "878787",
        103: "8787af",
        104: "8787d7",
        105: "8787ff",
        106: "87af00",
        107: "87af5f",
        108: "87af87",
        109: "87afaf",
        110: "87afd7",
        111: "87afff",
        112: "87d700",
        113: "87d75f",
        114: "87d787",
        115: "87d7af",
        116: "87d7d7",
        117: "87d7ff",
        118: "87ff00",
        119: "87ff5f",
        120: "87ff87",
        121: "87ffaf",
        122: "87ffd7",
        123: "87ffff",
        124: "af0000",
        125: "af005f",
        126: "af0087",
        127: "af00af",
        128: "af00d7",
        129: "af00ff",
        130: "af5f00",
        131: "af5f5f",
        132: "af5f87",
        133: "af5faf",
        134: "af5fd7",
        135: "af5fff",
        136: "af8700",
        137: "af875f",
        138: "af8787",
        139: "af87af",
        140: "af87d7",
        141: "af87ff",
        142: "afaf00",
        143: "afaf5f",
        144: "afaf87",
        145: "afafaf",
        146: "afafd7",
        147: "afafff",
        148: "afd700",
        149: "afd75f",
        150: "afd787",
        151: "afd7af",
        152: "afd7d7",
        153: "afd7ff",
        154: "afff00",
        155: "afff5f",
        156: "afff87",
        157: "afffaf",
        158: "afffd7",
        159: "afffff",
        160: "d70000",
        161: "d7005f",
        162: "d70087",
        163: "d700af",
        164: "d700d7",
        165: "d700ff",
        166: "d75f00",
        167: "d75f5f",
        168: "d75f87",
        169: "d75faf",
        170: "d75fd7",
        171: "d75fff",
        172: "d78700",
        173: "d7875f",
        174: "d78787",
        175: "d787af",
        176: "d787d7",
        177: "d787ff",
        178: "d7af00",
        179: "d7af5f",
        180: "d7af87",
        181: "d7afaf",
        182: "d7afd7",
        183: "d7afff",
        184: "d7d700",
        185: "d7d75f",
        186: "d7d787",
        187: "d7d7af",
        188: "d7d7d7",
        189: "d7d7ff",
        190: "d7ff00",
        191: "d7ff5f",
        192: "d7ff87",
        193: "d7ffaf",
        194: "d7ffd7",
        195: "d7ffff",
        196: "ff0000",
        197: "ff005f",
        198: "ff0087",
        199: "ff00af",
        200: "ff00d7",
        201: "ff00ff",
        202: "ff5f00",
        203: "ff5f5f",
        204: "ff5f87",
        205: "ff5faf",
        206: "ff5fd7",
        207: "ff5fff",
        208: "ff8700",
        209: "ff875f",
        210: "ff8787",
        211: "ff87af",
        212: "ff87d7",
        213: "ff87ff",
        214: "ffaf00",
        215: "ffaf5f",
        216: "ffaf87",
        217: "ffafaf",
        218: "ffafd7",
        219: "ffafff",
        220: "ffd700",
        221: "ffd75f",
        222: "ffd787",
        223: "ffd7af",
        224: "ffd7d7",
        225: "ffd7ff",
        226: "ffff00",
        227: "ffff5f",
        228: "ffff87",
        229: "ffffaf",
        230: "ffffd7",
        231: "ffffff",
        # Grayscale:
        232: "080808",
        233: "121212",
        234: "1c1c1c",
        235: "262626",
        236: "303030",
        237: "3a3a3a",
        238: "444444",
        239: "4e4e4e",
        240: "585858",
        241: "626262",
        242: "6c6c6c",
        243: "767676",
        244: "808080",
        245: "8a8a8a",
        246: "949494",
        247: "9e9e9e",
        248: "a8a8a8",
        249: "b2b2b2",
        250: "bcbcbc",
        251: "c6c6c6",
        252: "d0d0d0",
        253: "dadada",
        254: "e4e4e4",
        255: "eeeeee"
    }

    # Helper functions
    def require_auth(method):
        """
        An equivalent to tornado.web.authenticated for WebSockets
        (TerminalWebSocket, specifically).
        """
        @wraps(method)
        def wrapper(self, *args, **kwargs):
            if not self.get_current_user():
                self.write_message(_("Only valid users please.  Thanks!"))
                self.close() # Close the WebSocket
            return method(self, *args, **kwargs)
        return wrapper

    def kill_session(session, kill_dtach=False):
        """
        Terminates all the processes associated with *session* and then removes
        *session* from the global SESSIONS dict.  If *kill_dtach* is True, will
        also call kill_dtached_proc() on the terminal processes.
        """
        for term in list(SESSIONS[session].keys()):
            if isinstance(term, int) and term in SESSIONS[session]:
                if SESSIONS[session][term]['multiplex'].isalive():
                    SESSIONS[session][term]['multiplex'].terminate()
                if kill_dtach:
                    kill_dtached_proc(session, term)
        del SESSIONS[session]

    @atexit.register # I love this feature!
    def kill_all_sessions(kill_dtach=False):
        """
        Calls kill_session() on all sessions in the SESSIONS dict.
        """
        for session in SESSIONS.keys():
            kill_session(session, kill_dtach)

    def timeout_sessions(kill_dtach=False):
        """
        Loops over the SESSIONS dict killing any sessions that haven't been used
        for the length of time specified in *TIMEOUT* (global).  The value of
        *TIMEOUT* can be set in server.conf or specified on the command line via the
        *session_timeout* value.  Arguments:

         * *kill_dtach* - If True, will call kill_dtached_proc() on each terminal to ensure it dies.

        .. note:: This function is meant to be called via Tornado's ioloop.PeriodicCallback().
        """
        #logging.debug("timeout_sessions() TIMEOUT: %s" % TIMEOUT)
        try:
            if not SESSIONS: # Last client has timed out
                logging.info(_("All user sessions have terminated."))
                global WATCHER
                if WATCHER:
                    WATCHER.stop() # Stop ourselves
                    WATCHER = None # Reset so authenticate() will know to start it
            for session in list(SESSIONS.keys()):
                if "last_seen" not in SESSIONS[session]:
                    # Session is in the process of being created.  We'll check it
                    # the next time timeout_sessions() is called.
                    continue
                if SESSIONS[session]["last_seen"] == 'connected':
                    # Connected sessions do not need to be checked for timeouts
                    continue
                if datetime.now() > SESSIONS[session]["last_seen"] + TIMEOUT:
                    # Kill the session
                    logging.info(_("{session} timeout.".format(session=session)))
                    kill_session(session, kill_dtach)
        except Exception as e:
            logging.info(_(
                "Exception encountered in timeout_sessions(): {exception}".format(
                    exception=e)
            ))
            import traceback
            traceback.print_exc(file=sys.stdout)

    def cleanup_session_logs(users_dir, max_age):
        """
        Cleans up all user's session logs older than *max_age* (timedelta) given the
        *users_dir* (string).  The session log directory is assumed to be:

            *users_dir*/<user>/logs
        """
        logging.debug("cleanup_session_logs()")
        for user in os.listdir(users_dir):
            logs_path = os.path.join(users_dir, user, 'logs')
            if not os.path.exists(logs_path):
                # Nothing to do
                continue
            for log_name in os.listdir(logs_path):
                log_path = os.path.join(logs_path, log_name)
                mtime = time.localtime(os.stat(log_path).st_mtime)
                # Convert to a datetime object for easier comparison
                mtime = datetime.fromtimestamp(time.mktime(mtime))
                if datetime.now() - mtime > max_age:
                    # The log is older than max_age, remove it
                    os.remove(log_path)

    # Classes
    class HTTPSRedirectHandler(tornado.web.RequestHandler):
        """
        A handler to redirect clients from HTTP to HTTPS.
        """
        def get(self):
            """Just redirects the client from HTTP to HTTPS"""
            port = self.settings['port']
            url_prefix = self.settings['url_prefix']
            host = self.request.headers.get('Host', 'localhost')
            self.redirect(
                'https://%s:%s%s' % (host, port, url_prefix))

    class StaticHandler(tornado.web.StaticFileHandler):
        """
        An override of :class:`tornado.web.StaticFileHandler` to ensure that the
        Access-Control-Allow-Origin header gets set correctly.
        """
        # This is the only function we need to override thanks to the thoughtfulness
        # of the Tornado devs.
        def set_extra_headers(self, path):
            """
            Adds the Access-Control-Allow-Origin header to allow cross-origin
            access to static content for applications embedding Gate One.
            Specifically, this is necessary in order to support loading fonts
            from different origins.
            """
            self.set_header('Access-Control-Allow-Origin', '*')

    class BaseHandler(tornado.web.RequestHandler):
        """
        A base handler that all Gate One RequestHandlers will inherit methods from.
        """
        # Right now it's just the one function...
        def get_current_user(self):
            """Tornado standard method--implemented our way."""
            user_json = self.get_secure_cookie("gateone_user")
            if user_json:
                user = json_decode(user_json)
                if user and 'upn' not in user:
                    return None
                return user
        # More may be added in the future

    class MainHandler(BaseHandler):
        """
        Renders index.html which loads Gate One.

        Will include the minified version of gateone.js if available as
        gateone.min.js.

        Will encode GATEONE_DIR/static/bell.ogg as a data:URI and put it as the
        <source> of the <audio> tag inside the index.html template.  Gate One
        administrators can replace bell.ogg with whatever they like but the file
        size should be less than 32k when encoded to Base64.
        """
        # TODO: Add the ability for users to define their own individual bells.
        @tornado.web.authenticated
        @tornado.web.addslash
        def get(self):
            hostname = os.uname()[1]
            gateone_js = "%sstatic/gateone.js" % self.settings['url_prefix']
            minified_js_abspath = os.path.join(GATEONE_DIR, 'static')
            minified_js_abspath = os.path.join(
                minified_js_abspath, 'gateone.min.js')
            js_init = self.settings['js_init']
            # Use the minified version if it exists
            if os.path.exists(minified_js_abspath):
                gateone_js = "%sstatic/gateone.min.js" % self.settings['url_prefix']
            template_path = os.path.join(GATEONE_DIR, 'templates')
            index_path = os.path.join(template_path, 'index.html')
            head_html = ""
            body_html = ""
            for plugin, hooks in PLUGIN_HOOKS.items():
                if 'HTML' in hooks:
                    if 'head' in hooks['HTML']:
                        if hooks['HTML']['head']:
                            for item in hooks['HTML']['head']:
                                head_html += "%s\n" % item
                    if 'body' in hooks['HTML']:
                        if hooks['HTML']['body']:
                            for item in hooks['HTML']['body']:
                                body_html += "%s\n" % item
            self.render(
                index_path,
                hostname=hostname,
                gateone_js=gateone_js,
                jsplugins=PLUGINS['js'],
                cssplugins=PLUGINS['css'],
                js_init=js_init,
                url_prefix=self.settings['url_prefix'],
                head=head_html,
                body=body_html
            )

    class PluginCSSTemplateHandler(BaseHandler):
        """
        Renders plugin CSS template files, passing them the same *prefix* and
        *container* variables used by the StyleHandler.  This is so we don't need a
        CSS template rendering function in every plugin that needs to use {{prefix}}
        or {{container}}.

        gateone.js will automatically load all \*.css files in plugin template
        directories using this method.
        """
        # Had to disable authentication for this for the embedded stuff to work.
        # Not a big deal...  Just some stylesheets.  To an attacker it's like
        # peering into a window and seeing the wallpaper.
        def get(self):
            container = self.get_argument("container")
            prefix = self.get_argument("prefix")
            plugin = self.get_argument("plugin")
            template = self.get_argument("template")
            templates_path = os.path.join(GATEONE_DIR, 'templates')
            plugin_templates_path = os.path.join(templates_path, plugin)
            plugin_template = os.path.join(plugin_templates_path, "%s.css" % plugin)
            self.set_header('Content-Type', 'text/css')
            try:
                self.render(
                    plugin_template,
                    container=container,
                    prefix=prefix,
                    url_prefix=self.settings['url_prefix']
                )
            except IOError:
                # The provided plugin/template combination was not found
                logging.error(_("%s.css was not found" % plugin_template))

    class JSPluginsHandler(BaseHandler):
        """
        Combines all JavaScript plugins into a single file to keep things simple and
        speedy.
        """
        # No auth for this...  Not really necessary (just serves up a static file).
        def get(self):
            self.set_header('Content-Type', 'application/javascript')
            # This is so we can load combined_plugins in a <script> tag without
            # having to accept the SSL certificate:
            self.set_header('Access-Control-Allow-Origin', '*')
            plugins = get_plugins(os.path.join(GATEONE_DIR, "plugins"))
            static_dir = os.path.join(GATEONE_DIR, "static")
            combined_plugins = os.path.join(static_dir, "combined_plugins.js")
            if os.path.exists(combined_plugins):
                with open(combined_plugins) as f:
                    js_data = f.read()
                    if len(js_data) < 100: # Needs to be created
                        self.write(self._combine_plugins())
                        return
                    else: # It hasn't changed, send it as-is
                        self.write(js_data)
            else: # File doesn't exist, create it and send it to the client
                self.write(self._combine_plugins())

        def _combine_plugins(self):
            """
            Combines all plugin .js files into one (combined_plugins.js)
            """
            plugins = get_plugins(os.path.join(GATEONE_DIR, "plugins"))
            static_dir = os.path.join(GATEONE_DIR, "static")
            combined_plugins = os.path.join(static_dir, "combined_plugins.js")
            out = ""
            for js_plugin in plugins['js']:
                js_path = os.path.join(GATEONE_DIR, js_plugin.lstrip('/'))
                with open(js_path) as f:
                    out += f.read()
            with open(combined_plugins, 'w') as f:
                f.write(out)
            return out

    class TerminalWebSocket(WebSocketHandler):
        """
        The main WebSocket interface for Gate One, this class is setup to call
        'commands' which are methods registered in self.commands.  Methods that are
        registered this way will be exposed and directly callable over the
        WebSocket.
        """
        def __init__(self, application, request):
            WebSocketHandler.__init__(self, application, request)
            self.commands = {
                'ping': self.pong,
                'authenticate': self.authenticate,
                'new_terminal': self.new_terminal,
                'set_terminal': self.set_terminal,
                'kill_terminal': self.kill_terminal,
                'c': self.char_handler, # Just 'c' to keep the bandwidth down
                'write_chars': self.write_chars,
                'refresh': self.refresh_screen,
                'full_refresh': self.full_refresh,
                'resize': self.resize,
                'get_bell': self.get_bell,
                'get_webworker': self.get_webworker,
                'get_style': self.get_style,
                #'get_js': self.get_js,
                'enumerate_themes': self.enumerate_themes,
                'manual_title': self.manual_title,
                'debug_terminal': self.debug_terminal
            }
            self.terms = {}
            # So we can keep track and avoid sending unnecessary messages:
            self.titles = {}
            self.user = None
            self.em_dimensions = None
            # This is used to keep track of used API authentication signatures so
            # we can prevent replay attacks.
            self.prev_signatures = []
            self.origin_denied = True # Only allow valid origins

        def allow_draft76(self):
            """
            By overriding this function we're allowing the older version of the
            WebSockets protocol.  As long as communications happens over SSL there
            shouldn't be any security concerns with this.  This is mostly to support
            iOS Safari.
            """
            return True

        def get_current_user(self):
            """
            Mostly identical to the function of the same name in MainHandler.  The
            difference being that when API authentication is enabled the WebSocket
            will expect and perform its own auth of the client.
            """
            if self.user:
                return self.user
            user_json = self.get_secure_cookie("gateone_user")
            if not user_json:
                if not self.settings['auth']:
                    # This can happen if the user's browser isn't allowing
                    # persistent cookies (e.g. incognito mode)
                    return {'upn': 'ANONYMOUS', 'session': generate_session_id()}
                return None
            return json_decode(user_json)

        def open(self):
            """
            Called when a new WebSocket is opened.  Will deny access to any
            origin that is not defined in self.settings['origin'].
            """
            valid_origins = self.settings['origins']
            if 'Origin' in self.request.headers:
                origin_header = self.request.headers['Origin']
            elif 'Sec-Websocket-Origin' in self.request.headers: # Old version
                origin_header = self.request.headers['Sec-Websocket-Origin']
            origin_header = origin_header.lower() # hostnames are case-insensitive
            if '*' not in valid_origins:
                if origin_header not in valid_origins:
                    self.origin_denied = True
                    origin = origin_header
                    short_origin = origin.split('//')[1]
                    denied_msg = _("Access denied for origin: %s" % origin)
                    logging.error(denied_msg)
                    self.write_message(denied_msg)
                    self.write_message(_(
                        "If you feel this is incorrect you just have to add '%s' to"
                        " the 'origin' option in your server.conf.  See the docs "
                        "for details." % short_origin
                    ))
                    self.close()
            self.origin_denied = False
            # TODO: Make it so that idle WebSockets that haven't passed authentication tests get auto-closed within N seconds in order to prevent a DoS scenario where the attacker keeps all possible ports open indefinitely.
            # client_id is unique to the browser/client whereas session_id is unique
            # to the user.  It isn't used much right now but it will be useful in
            # the future once more stuff is running over WebSockets.
            self.client_id = generate_session_id()
            user = self.get_current_user()
            if user and 'upn' in user:
                logging.info(
                    _("WebSocket opened (%s).") % user['upn'])
            else:
                logging.info(_("WebSocket opened (unknown user)."))
            if user and 'upn' not in user: # Invalid user info
                logging.error(_("Unauthenticated WebSocket attempt."))
                # In case this is a legitimate client that simply had its auth info
                # expire/go bad, tell it to re-auth by calling the appropriate
                # action on the other side.
                message = {'reauthenticate': True}
                self.write_message(json_encode(message))
                self.close() # Close the WebSocket

        def on_message(self, message):
            """Called when we receive a message from the client."""
            # This is super useful when debugging:
            logging.debug("message: %s" % repr(message))
            if self.origin_denied:
                logging.error(_("Message rejected due to invalid origin."))
                self.close() # Close the WebSocket
            message_obj = None
            try:
                message_obj = json_decode(message) # JSON FTW!
                if not isinstance(message_obj, dict):
                    self.write_message(_("'Error: Message bust be a JSON dict.'"))
                    return
            except ValueError: # We didn't get JSON
                self.write_message(_("'Error: We only accept JSON here.'"))
                return
            if message_obj:
                for key, value in message_obj.items():
                    if key in PLUGIN_WS_CMDS:
                        try: # Plugins first so they can override behavior if they wish
                            PLUGIN_WS_CMDS[key](value, tws=self)# tws==TerminalWebSocket
                        except (KeyError, TypeError, AttributeError) as e:
                            logging.error(_(
                                "Error running plugin WebSocket action: %s" % key))
                    else:
                        try:
                            if value:
                                self.commands[key](value)
                            else:
                                # Try, try again
                                self.commands[key]()
                        except (KeyError, TypeError, AttributeError) as e:
                            logging.debug(e)
                            if self.settings['logging'] == "debug":
                                import traceback
                                traceback.print_exc(file=sys.stdout)
                            logging.error(_('Unknown WebSocket action: %s' % key))

        def on_close(self):
            """
            Called when the client terminates the connection.

            .. note:: Normally self.refresh_screen() catches the disconnect first and this method won't end up being called.
            """
            logging.debug("on_close()")
            user = self.get_current_user()
            if user and user['session'] in SESSIONS:
                # Update 'last_seen' with a datetime object for accuracy
                SESSIONS[user['session']]['last_seen'] = datetime.now()
                # Remove all attached callbacks so we're not wasting memory/CPU on
                # disconnected clients
                for term in SESSIONS[user['session']]:
                    if isinstance(term, int):
                        try:
                            multiplex = SESSIONS[user['session']][term]['multiplex']
                            multiplex.remove_all_callbacks(self.callback_id)
                            client_dict = SESSIONS[user['session']][term][
                                self.client_id]
                            term_emulator = multiplex.term
                            term_emulator.remove_all_callbacks(self.callback_id)
                            # Remove anything associated with the client_id
                            multiplex.io_loop.remove_timeout(
                                client_dict['refresh_timeout'])
                            del SESSIONS[user['session']][term][self.client_id]
                        except AttributeError:
                            # User never completed opening a terminal so
                            # self.callback_id is missing.  Nothing to worry about
                            if self.client_id in SESSIONS[user['session']][term]:
                                del SESSIONS[user['session']][term][self.client_id]
            if user and 'upn' in user:
                logging.info(
                    _("WebSocket closed (%s).") % user['upn'])
            else:
                logging.info(_("WebSocket closed (unknown user)."))

        def pong(self, timestamp):
            """
            Responds to a client 'ping' request...  Just returns the given
            timestamp back to the client so it can measure round-trip time.
            """
            message = {'pong': timestamp}
            self.write_message(json_encode(message))

        def authenticate(self, settings):
            """
            Authenticates the client by first trying to use the 'gateone_user'
            cookie or if Gate One is configured to use API authentication it will
            use *settings['auth']*.  Additionally, it will accept
            *settings['container']* and *settings['prefix']* to apply those to the
            equivalent properties (self.container and self.prefix).
            """
            logging.debug("authenticate(): %s" % settings)
            if 'Origin' in self.request.headers:
                origin_header = self.request.headers['Origin']
            elif 'Sec-Websocket-Origin' in self.request.headers: # Old version
                origin_header = self.request.headers['Sec-Websocket-Origin']
            # Make sure the client is authenticated if authentication is enabled
            if self.settings['auth'] and self.settings['auth'] != 'api':
                try:
                    user = self.get_current_user()
                    if not user:
                        logging.error(_("Unauthenticated WebSocket attempt."))
                        # This usually happens when the cookie_secret gets changed
                        # resulting in "Invalid cookie..." errors.  If we tell the
                        # client to re-auth the problem should correct itself.
                        message = {'reauthenticate': True}
                        self.write_message(json_encode(message))
                        return
                    elif user and user['upn'] == 'ANONYMOUS':
                        logging.error(_("Unauthenticated WebSocket attempt."))
                        # This can happen when a client logs in with no auth type
                        # configured and then later the server is configured to use
                        # authentication.  The client must be told to re-auth:
                        message = {'reauthenticate': True}
                        self.write_message(json_encode(message))
                        return
                except KeyError: # 'upn' wasn't in user
                    # Force them to authenticate
                    message = {'reauthenticate': True}
                    self.write_message(json_encode(message))
                    self.close() # Close the WebSocket
            elif self.settings['auth'] and self.settings['auth'] == 'api':
                if 'auth' in settings.keys():
                    # 'auth' message should look like this:
                    # {
                    #    'api_key': 'MjkwYzc3MDI2MjhhNGZkNDg1MjJkODgyYjBmN2MyMTM4M',
                    #    'upn': 'joe@company.com',
                    #    'timestamp': 1323391717238,
                    #    'signature': <gibberish>,
                    #    'signature_method': 'HMAC-SHA1',
                    #    'api_version': '1.0'
                    # }
                    #
                    # *api_key* is the first half of what gets generated when you
                    #   run ./gateone --new_api_key.
                    # *upn* is the User Principal Name of the user.  This is
                    #   typically something like "joe@company.com".
                    # *timestamp* is a JavaScript Date() object converted into an
                    #   "time since the epoch": var timestamp = new Date().getTime()
                    # *signature* is an HMAC signature of the previous three
                    #   variables that was created using the given API key's secret.
                    # *signature_method* is the HMAC hashing algorithm to use for
                    #   the signature.  Only HMAC-SHA1 is supported for now.
                    # *api_version* is the auth API version.  Always "1.0" for now.
                    #
                    # For reference, here's how to make a signature using PHP:
                    # $authobj = array('api_key' => 'M2I1MzJmZjk4MTEwNDk2Zjk4MjMwNmMwMTVkODQzMTEyO', 'upn' => $_SERVER['REMOTE_USER'], 'timestamp' => time() . '0000', 'signature_method' => 'HMAC-SHA1', 'api_version' => '1.0');
                    # $authobj['signature'] = hash_hmac('sha1', $authobj['api_key'] . $authobj['upn'] . $authobj['timestamp'], '<secret>');
                    # Note that the order matters:  api_key -> upn -> timestamp
                    auth_obj = settings['auth']
                    if 'api_key' in auth_obj:
                        # Assume everything else is present if the api_key is there
                        api_key = auth_obj['api_key']
                        upn = auth_obj['upn']
                        timestamp = auth_obj['timestamp']
                        signature = auth_obj['signature']
                        signature_method = auth_obj['signature_method']
                        api_version = auth_obj['api_version']
                        if signature_method != 'HMAC-SHA1':
                            message = {
                                'notice': _(
                                    'AUTHENTICATION ERROR: Unsupported API auth '
                                    'signature method: %s' % signature_method)
                            }
                            self.write_message(json_encode(message))
                            return
                        secret = self.settings['api_keys'][api_key]
                        # Check the signature against existing API keys
                        sig_check = tornado.web._create_signature(
                            secret, api_key, upn, timestamp)
                        if sig_check == signature:
                            # Everything matches (great!) so now we do due diligence
                            # by checking the timestamp against the
                            # api_timestamp_window setting and whether or not we've
                            # already used it (to prevent replay attacks).
                            if signature in self.prev_signatures:
                                logging.error(_(
                                "API authentication replay attack detected!  User: "
                                "%s, Remote IP: %s, Origin: %s" % (
                                    upn, self.request.remote_ip, origin_header)))
                                message = {'notice': _(
                                    'AUTH FAILED: Replay attack detected!  This '
                                    'event has been logged.')}
                                self.write_message(json_encode(message))
                                self.close()
                                return
                            window = self.settings['api_timestamp_window']
                            then = datetime.fromtimestamp(int(timestamp)/1000)
                            time_diff = datetime.now() - then
                            if time_diff > window:
                                logging.error(_(
                                "API authentication failed due to an expired auth "
                                "object.  If you just restarted the server this is "
                                "normal (users just need to reload the page).  If "
                                " this problem persists it could be a problem with "
                                "the server's clock (either this server or the "
                                "server(s) embedding Gate One)."
                                ))
                                message = {'notice': _(
                                    'AUTH FAILED: Authentication object timed out. '
                                    'Try reloading this page (F5).')}
                                self.write_message(json_encode(message))
                                message = {'notice': _(
                                    'AUTH FAILED: If the problem persists after '
                                    'reloading this page please contact your server'
                                    ' administrator to notify them of the issue.')}
                                self.write_message(json_encode(message))
                                self.close()
                                return
                            logging.debug(_("API Authentication Successful"))
                            self.prev_signatures.append(signature) # Prevent replays
                    # Make a directory to store this user's settings/files/logs/etc
                            user_dir = os.path.join(self.settings['user_dir'], upn)
                            if not os.path.exists(user_dir):
                                logging.info(
                                    _("Creating user directory: %s" % user_dir))
                                mkdir_p(user_dir)
                                os.chmod(user_dir, 0o770)
                            session_file = os.path.join(user_dir, 'session')
                            if os.path.exists(session_file):
                                session_data = open(session_file).read()
                                self.user = json_decode(session_data)
                            else:
                                with open(session_file, 'w') as f:
                            # Save it so we can keep track across multiple clients
                                    self.user = {
                                        'upn': upn, # FYI: UPN == userPrincipalName
                                        'session': generate_session_id()
                                    }
                                    session_info_json = json_encode(self.user)
                                    f.write(session_info_json)
                        else:
                            logging.error(_(
                                "WebSocket auth failed signature check."))
                else:
                    logging.error(_("Missing API Key in authentication object"))
            else: # Anonymous auth
                # Double-check there isn't a user set in the cookie (i.e. we have
                # recently changed Gate One's settings).  If there is, force it
                # back to ANONYMOUS.
                if settings['auth']: # Authentication from localStorage data
                    # Authenticate/decode the encoded auth info
                    self.user = json_decode(self.get_secure_cookie(
                        'gateone_user', value=settings['auth']))
                else:
                    # Generate a new session/anon user
                    self.user = self.get_current_user()
                    # Also store/update their session info in localStorage
                    encoded_user = self.create_signed_value(
                        'gateone_user', tornado.escape.json_encode(self.user))
                    session_message = {'gateone_user': encoded_user}
                    self.write_message(json_encode(session_message))
                if self.user['upn'] != 'ANONYMOUS':
                    # Gate One server's auth config probably changed
                    message = {'reauthenticate': True}
                    self.write_message(json_encode(message))
                    #self.close() # Close the WebSocket
                    return
            try:
                user = self.get_current_user()
                if user and 'session' in user:
                    self.session = user['session']
                else:
                    logging.error(_("Authentication failed for unknown user"))
                    message = {'notice': _('AUTHENTICATION ERROR: User unknown')}
                    self.write_message(json_encode(message))
                    return
            except Exception as e:
                logging.error(_(
                    "Exception encountered trying to authenticate: %s" % e))
                return
            try:
                # Execute any post-authentication hooks that plugins have registered
                if PLUGIN_AUTH_HOOKS:
                    for auth_hook in PLUGIN_AUTH_HOOKS:
                        auth_hook(self.get_current_user(), self.settings)
            except Exception as e:
                logging.error(_("Exception in registered Auth hook: %s" % e))
            # Apply the container/prefix settings (if present)
            # NOTE:  Currently these are only used by the logging plugin
            if 'container' in settings:
                self.container = settings['container']
            if 'prefix' in settings:
                self.prefix = settings['prefix']
            # This check is to make sure there's no existing session so we don't
            # accidentally clobber it.
            if self.session not in SESSIONS:
                # Old session is no good, start a new one:
                SESSIONS[self.session] = {
                    'last_seen': 'connected'
                }
            else:
                SESSIONS[self.session]['last_seen'] = 'connected'
            terminals = []
            for term in list(SESSIONS[self.session].keys()):
                if isinstance(term, int):
                    terminals.append(term) # Only terminals are integers in the dict
            # Check for any dtach'd terminals we might have missed
            if self.settings['dtach']:
                session_dir = self.settings['session_dir']
                session_dir = os.path.join(session_dir, self.session)
                if not os.path.exists(session_dir):
                    mkdir_p(session_dir)
                    os.chmod(session_dir, 0o770)
                for item in os.listdir(session_dir):
                    if item.startswith('dtach_'):
                        term = int(item.split('_')[1])
                        if term not in terminals:
                            terminals.append(term)
            terminals.sort() # Put them in order so folks don't get confused
            message = {
                'terminals': terminals,
            # This is just so the client has a human-readable point of reference:
                'set_username': self.get_current_user()['upn']
            }
            # TODO: Add a hook here for plugins to send their own messages when a
            #       given terminal is reconnected.
            self.write_message(json_encode(message))
            # Startup the watcher if it isn't already running
            global WATCHER
            if not WATCHER:
                interval = 30*1000 # Check every 30 seconds
                watcher = partial(timeout_sessions, options.dtach)
                WATCHER = tornado.ioloop.PeriodicCallback(watcher, interval)
                WATCHER.start()

        def new_multiplex(self, cmd, term_id, logging=True):
            """
            Returns a new instance of :py:class:`termio.Multiplex` with the proper global and
            client-specific settings.

                * *cmd* - The command to execute inside of Multiplex.
                * *term_id* - The terminal to associate with this Multiplex or a descriptive identifier (it's only used for logging purposes).
                * *logging* - If False, logging will be disabled for this instance of Multiplex (even if it would otherwise be enabled).
            """
            user_dir = self.settings['user_dir']
            try:
                user = self.get_current_user()['upn']
            except:
                # No auth, use ANONYMOUS (% is there to prevent conflicts)
                user = r'ANONYMOUS' # Don't get on this guy's bad side
            session_dir = self.settings['session_dir']
            session_dir = os.path.join(session_dir, self.session)
            log_path = None
            syslog_logging = False
            if logging:
                syslog_logging = self.settings['syslog_session_logging']
                if self.settings['session_logging']:
                    log_dir = os.path.join(user_dir, user)
                    log_dir = os.path.join(log_dir, 'logs')
                    # Create the log dir if not already present
                    if not os.path.exists(log_dir):
                        mkdir_p(log_dir)
                    log_name = datetime.now().strftime('%Y%m%d%H%M%S%f.golog')
                    log_path = os.path.join(log_dir, log_name)
            facility = string_to_syslog_facility(self.settings['syslog_facility'])
            return termio.Multiplex(
                cmd,
                log_path=log_path,
                user=user,
                term_id=term_id,
                syslog=syslog_logging,
                syslog_facility=facility,
                syslog_host=self.settings['syslog_host']
            )

        def term_ended(self, term):
            """
            Sends the 'term_ended' message to the client letting it know that the
            given *term* is no more.
            """
            message = {'term_ended': term}
            self.write_message(json_encode(message))

        @require_auth
        def new_terminal(self, settings):
            """
            Starts up a new terminal associated with the user's session using
            *settings* as the parameters.  If a terminal already exists with the
            same number as *settings[term]*, self.set_terminal() will be called
            instead of starting a new terminal (so clients can resume their session
            without having to worry about figuring out if a new terminal already
            exists or not).
            """
            logging.debug("%s new_terminal(): %s" % (
                self.get_current_user()['upn'], settings))
            if self.session not in SESSIONS:
                # This happens when timeout_sessions() times out a session
                # Tell the client it timed out:
                message = {'timeout': None}
                self.write_message(json_encode(message))
                return
            self.current_term = term = settings['term']
            self.rows = rows = settings['rows']
            self.cols = cols = settings['cols']
            if 'em_dimensions' in settings:
                self.em_dimensions = {
                    'height': settings['em_dimensions']['h'],
                    'width': settings['em_dimensions']['w']
                }
            user_dir = self.settings['user_dir']
            needs_full_refresh = False
            if term not in SESSIONS[self.session]:
                # Setup the requisite dict
                SESSIONS[self.session][term] = {
                    'last_activity': datetime.now(),
                    'title': 'Gate One',
                    'manual_title': False
                }
            if self.client_id not in SESSIONS[self.session][term]:
                SESSIONS[self.session][term][self.client_id] = {
                    # Used by refresh_screen()
                    'refresh_timeout': None
                }
            if 'multiplex' not in SESSIONS[self.session][term]:
                # Start up a new terminal
                SESSIONS[self.session][term]['created'] = datetime.now()
                # NOTE: Not doing anything with 'created'...  yet!
                now = int(round(time.time() * 1000))
                try:
                    user = self.get_current_user()['upn']
                except:
                    # No auth, use ANONYMOUS (% is there to prevent conflicts)
                    user = 'ANONYMOUS' # Don't get on this guy's bad side
                cmd = cmd_var_swap(CMD,   # Swap out variables like %USER% in CMD
                    session=self.session, # with their real-world values.
                    session_hash=short_hash(self.session),
                    user_dir=user_dir,
                    user=user,
                    time=now
                )
                resumed_dtach = False
                session_dir = self.settings['session_dir']
                session_dir = os.path.join(session_dir, self.session)
                # Create the session dir if not already present
                if not os.path.exists(session_dir):
                    mkdir_p(session_dir)
                    os.chmod(session_dir, 0o770)
                if self.settings['dtach']: # Wrap in dtach (love this tool!)
                    dtach_path = "%s/dtach_%s" % (session_dir, term)
                    if os.path.exists(dtach_path):
                        # Using 'none' for the refresh because the EVIL termio
                        # likes to manage things like that on his own...
                        cmd = "dtach -a %s -E -z -r none" % dtach_path
                        resumed_dtach = True
                    else: # No existing dtach session...  Make a new one
                        cmd = "dtach -c %s -E -z -r none %s" % (dtach_path, cmd)
                SESSIONS[self.session][term]['multiplex'] = self.new_multiplex(
                    cmd, term)
                # Set some environment variables so the programs we execute can use
                # them (very handy).  Allows for "tight integration" and "synergy"!
                env = {
                    'GO_USER_DIR': user_dir,
                    'GO_USER': user,
                    'GO_TERM': str(term),
                    'GO_SESSION': self.session,
                    'GO_SESSION_DIR': session_dir
                }
                SESSIONS[self.session][term]['multiplex'].spawn(
                    rows, cols, env=env, em_dimensions=self.em_dimensions)
            else:
                # Terminal already exists
                if SESSIONS[self.session][term]['multiplex'].isalive():
                    # It's ALIVE!!!
                    SESSIONS[self.session][term]['multiplex'].resize(
                        rows, cols, ctrl_l=False, em_dimensions=self.em_dimensions)
                    message = {'term_exists': term}
                    self.write_message(json_encode(message))
                    # This resets the screen diff
                    SESSIONS[self.session][term]['multiplex'].prev_output[
                        self.client_id] = [None for a in xrange(rows-1)]
                    # Remind the client about this terminal's title
                    self.set_title(term, force=True)
                else:
                    # Tell the client this terminal is no more
                    self.term_ended(term)
                    return
            # Setup callbacks so that everything gets called when it should
            self.callback_id = callback_id = "%s;%s;%s" % (
                self.client_id, self.request.host, self.request.remote_ip)
            # NOTE: request.host is the FQDN or IP the user entered to open Gate One
            # so if you want to have multiple browsers open to the same user session
            # from the same IP just use an alternate hostname/IP for the URL.
            # Setup the termio callbacks
            refresh = partial(self.refresh_screen, term)
            multiplex = SESSIONS[self.session][term]['multiplex']
            multiplex.add_callback(multiplex.CALLBACK_UPDATE, refresh, callback_id)
            ended = partial(self.term_ended, term)
            multiplex.add_callback(multiplex.CALLBACK_EXIT, ended, callback_id)
            # Setup the terminal emulator callbacks
            term_emulator = multiplex.term
            set_title = partial(self.set_title, term)
            term_emulator.add_callback(
                terminal.CALLBACK_TITLE, set_title, callback_id)
            set_title() # Set initial title
            bell = partial(self.bell, term)
            term_emulator.add_callback(
                terminal.CALLBACK_BELL, bell, callback_id)
            term_emulator.add_callback(
                terminal.CALLBACK_OPT, self.esc_opt_handler, callback_id)
            mode_handler = partial(self.mode_handler, term)
            term_emulator.add_callback(
                terminal.CALLBACK_MODE, mode_handler, callback_id)
            reset_term = partial(self.reset_terminal, term)
            term_emulator.add_callback(
                terminal.CALLBACK_RESET, reset_term, callback_id)
            dsr = partial(self.dsr, term)
            term_emulator.add_callback(
                terminal.CALLBACK_DSR, dsr, callback_id)
            # Call any registered plugin Terminal hooks
            if PLUGIN_TERM_HOOKS:
                for hook, func in PLUGIN_TERM_HOOKS.items():
                    term_emulator.add_callback(hook, func(self))
            # NOTE: refresh_screen will also take care of cleaning things up if
            #       SESSIONS[self.session][term]['multiplex'].isalive() is False
            self.refresh_screen(term, True) # Send a fresh screen to the client
            # Restore application cursor keys mode if set
            if 'application_mode' in SESSIONS[self.session][term]:
                current_setting = SESSIONS[self.session][term]['application_mode']
                self.mode_handler(term, '1', current_setting)
            if self.settings['logging'] == 'debug':
                message = {
                    'notice': _(
                        "WARNING: Logging is set to DEBUG.  All keystrokes will be "
                        "logged!")
                }
                self.write_message(message)

        @require_auth
        def kill_terminal(self, term):
            """
            Kills *term* and any associated processes.
            """
            logging.debug("killing terminal: %s" % term)
            term = int(term)
            if term not in SESSIONS[self.session]:
                return # Nothing to do
            multiplex = SESSIONS[self.session][term]['multiplex']
            # Remove the EXIT callback so the terminal doesn't restart itself
            multiplex.remove_callback(multiplex.CALLBACK_EXIT, self.callback_id)
            try:
                if self.settings['dtach']: # dtach needs special love
                    kill_dtached_proc(self.session, term)
                if multiplex.isalive():
                    multiplex.terminate()
            except KeyError as e:
                pass # The EVIL termio has killed my child!  Wait, that's good...
                     # Because now I don't have to worry about it!
            finally:
                del SESSIONS[self.session][term]

        @require_auth
        def set_terminal(self, term):
            """
            Sets `self.current_term = *term*` so we can determine where to send
            keystrokes.
            """
            self.current_term = term

        @require_auth
        def reset_terminal(self, term):
            """
            Tells the client to reset the terminal (clear the screen and remove
            scrollback).
            """
            message = {'reset_terminal': term}
            self.write_message(json_encode(message))

        @require_auth
        def set_title(self, term, force=False):
            """
            Sends a message to the client telling it to set the window title of
            *term* to whatever comes out of::

                SESSIONS[self.session][term]['multiplex'].term.get_title() # Whew! Say that three times fast!

            Example message::

                {'set_title': {'term': 1, 'title': "user@host"}}

            If *force* resolves to True the title will be sent to the cleint even if
            it matches the previously-set title.

            .. note:: Why the complexity on something as simple as setting the title?  Many prompts set the title.  This means we'd be sending a 'title' message to the client with nearly every screen update which is a pointless waste of bandwidth if the title hasn't changed.
            """
            logging.debug("set_title(%s, %s)" % (term, force))
            if SESSIONS[self.session][term]['manual_title']:
                if force:
                    title = SESSIONS[self.session][term]['title']
                    title_message = {'set_title': {'term': term, 'title': title}}
                    self.write_message(json_encode(title_message))
                return
            title = SESSIONS[self.session][term]['multiplex'].term.get_title()
            # Only send a title update if it actually changed
            if title != SESSIONS[self.session][term]['title'] or force:
                SESSIONS[self.session][term]['title'] = title
                title_message = {'set_title': {'term': term, 'title': title}}
                self.write_message(json_encode(title_message))

        @require_auth
        def manual_title(self, settings):
            """
            Sets the title of *settings['term']* to *settings['title']*.  Differs
            from :func:`set_title` in that this is an action that gets called by the
            client when the user sets a terminal title manually.
            """
            logging.debug("manual_title: %s" % settings)
            term = int(settings['term'])
            title = settings['title']
            if not title:
                title = SESSIONS[self.session][term]['multiplex'].term.get_title()
                SESSIONS[self.session][term]['manual_title'] = False
            else:
                SESSIONS[self.session][term]['manual_title'] = True
            SESSIONS[self.session][term]['title'] = title
            title_message = {'set_title': {'term': term, 'title': title}}
            self.write_message(json_encode(title_message))

        @require_auth
        def bell(self, term):
            """
            Sends a message to the client indicating that a bell was encountered in
            the given terminal (*term*).  Example message::

                {'bell': {'term': 1}}
            """
            bell_message = {'bell': {'term': term}}
            self.write_message(json_encode(bell_message))

        @require_auth
        def mode_handler(self, term, setting, boolean):
            """
            Handles mode settings that require an action on the client by pasing it
            a message like::

                {
                    'set_mode': {
                        'mode': setting,
                        'bool': True,
                        'term': term
                    }
                }
            """
            logging.debug(
                "mode_handler() term: %s, setting: %s, boolean: %s" %
                (term, setting, boolean))
            if setting in ['1']: # Only support this mode right now
                # So we can restore it:
                SESSIONS[self.session][term]['application_mode'] = boolean
                if boolean:
                    # Tell client to enable application cursor mode
                    mode_message = {'set_mode': {
                        'mode': setting,
                        'bool': True,
                        'term': term
                    }}
                    self.write_message(json_encode(mode_message))
                else:
                    # Tell client to disable application cursor mode
                    mode_message = {'set_mode': {
                        'mode': setting,
                        'bool': False,
                        'term': term
                    }}
                    self.write_message(json_encode(mode_message))

        def dsr(self, term, response):
            """
            Handles Device Status Report (DSR) calls from the underlying program
            that get caught by the terminal emulator.  *response* is what the
            terminal emulator returns from the CALLBACK_DSR callback.

            .. note:: This also handles the CSI DSR sequence.
            """
            SESSIONS[self.session][term]['multiplex'].write(response)

        def _send_refresh(self, term, full=False):
            """Sends a screen update to the client."""
            try:
                SESSIONS[self.session][term]['last_activity'] = datetime.now()
            except KeyError:
                # This can happen if the user disconnected in the middle of a screen
                # update.  Nothing to be concerned about.
                return # Ignore
            multiplex = SESSIONS[self.session][term]['multiplex']
            scrollback, screen = multiplex.dump_html(
                full=full, client_id=self.client_id)
            if [a for a in screen if a]:
                output_dict = {
                    'termupdate': {
                        'term': term,
                        'scrollback': scrollback,
                        'screen' : screen,
                        'ratelimiter': multiplex.ratelimiter_engaged
                    }
                }
                try:
                    self.write_message(json_encode(output_dict))
                except IOError: # Socket was just closed, no biggie
                    logging.info(
                     _("WebSocket closed (%s)") % self.get_current_user()['upn'])
                    multiplex = SESSIONS[self.session][term]['multiplex']
                    multiplex.remove_callback( # Stop trying to write
                        multiplex.CALLBACK_UPDATE, self.callback_id)

        @require_auth
        def refresh_screen(self, term, full=False):
            """
            Writes the state of the given terminal's screen and scrollback buffer to
            the client using `_send_refresh()`.  Also ensures that screen updates
            don't get sent too fast to the client by instituting a rate limiter that
            also forces a refresh every 150ms.  This keeps things smooth on the
            client side and also reduces the bandwidth used by the application (CPU
            too).

            If *full*, send the whole screen (not just the difference).
            """
            # Commented this out because it was getting annoying.
            # Note to self: add more levels of debugging beyond just "debug".
            #logging.debug(
                #"refresh_screen (full=%s) on %s" % (full, self.callback_id))
            if term:
                term = int(term)
            else:
                return # This just prevents an exception when the cookie is invalid
            try:
                msec = timedelta(milliseconds=50) # Keeps things smooth
                # In testing, 150 milliseconds was about as low as I could go and
                # still remain practical.
                force_refresh_threshold = timedelta(milliseconds=150)
                last_activity = SESSIONS[self.session][term]['last_activity']
                timediff = datetime.now() - last_activity
                sess = SESSIONS[self.session][term]
                client_dict = sess[self.client_id]
                multiplex = sess['multiplex']
                refresh = partial(self._send_refresh, term, full)
                # We impose a rate limit of max one screen update every 50ms by
                # wrapping the call to _send_refresh() in an IOLoop timeout that
                # gets cancelled and replaced if screen updates come in faster than
                # once every 50ms.  If screen updates are consistently faster than
                # that (e.g. a key is held down) we also force sending the screen
                # to the client every 150ms.  This ensures that no matter how fast
                # screen updates are happening the user will get at least one
                # update every 150ms.  It works out quite nice, actually.
                if client_dict['refresh_timeout']:
                    multiplex.io_loop.remove_timeout(client_dict['refresh_timeout'])
                if timediff > force_refresh_threshold:
                    refresh()
                else:
                    client_dict['refresh_timeout'] = multiplex.io_loop.add_timeout(
                        msec, refresh)
            except KeyError as e: # Session died (i.e. command ended).
                logging.debug(_("KeyError in refresh_screen: %s" % e))

        @require_auth
        def full_refresh(self, term):
            """Calls `self.refresh_screen(*term*, full=True)`"""
            try:
                term = int(term)
            except ValueError:
                logging.debug(_(
                    "Invalid terminal number given to full_refresh(): %s" % term))
            self.refresh_screen(term, full=True)

        @require_auth
        def resize(self, resize_obj):
            """
            Resize the terminal window to the rows/cols specified in *resize_obj*

            Example *resize_obj*::

                {'rows': 24, 'cols': 80}
            """
            logging.debug("resize(%s)" % repr(resize_obj))
            term = None
            if 'term' in resize_obj:
                term = int(resize_obj['term'])
            self.rows = resize_obj['rows']
            self.cols = resize_obj['cols']
            self.em_dimensions = {
                'height': resize_obj['em_dimensions']['h'],
                'width': resize_obj['em_dimensions']['w']
            }
            ctrl_l = False
            if 'ctrl_l' in resize_obj:
                ctrl_l = resize_obj['ctrl_l']
            if self.rows < 2 or self.cols < 2:
                # Fall back to a standard default:
                self.rows = 24
                self.cols = 80
            # If the user already has a running session, set the new terminal size:
            try:
                if term:
                    SESSIONS[self.session][term]['multiplex'].resize(
                        self.rows,
                        self.cols,
                        self.em_dimensions,
                        ctrl_l=ctrl_l
                    )
                else: # Resize them all
                    for term in list(SESSIONS[self.session].keys()):
                        if isinstance(term, int): # Skip the TidyThread
                            SESSIONS[self.session][term]['multiplex'].resize(
                                self.rows,
                                self.cols,
                                self.em_dimensions
                            )
            except KeyError: # Session doesn't exist yet, no biggie
                pass

        @require_auth
        def char_handler(self, chars, term=None):
            """
            Writes *chars* (string) to *term*.  If *term* is not provided the
            characters will be sent to the currently-selected terminal.
            """
            #logging.debug("char_handler(%s, %s)" % (repr(chars), repr(term)))
            if not term:
                term = self.current_term
            term = int(term) # Just in case it was sent as a string
            session = self.session
            if session in SESSIONS and term in SESSIONS[session]:
                if SESSIONS[session][term]['multiplex'].isalive():
                    if chars:
                        SESSIONS[ # Force an update
                            session][term]['multiplex'].ratelimit = time.time()
                        SESSIONS[session][term]['multiplex'].write(chars)

        @require_auth
        def write_chars(self, message):
            """
            Writes *message['chars']* to *message['term']*.  If *message['term']*
            is not present, *self.current_term* will be used.
            """
            #logging.debug('write_chars(%s)' % message)
            if 'chars' not in message:
                return # Invalid message
            if 'term' not in message:
                message['term'] = self.current_term
            try:
                self.char_handler(message['chars'], message['term'])
            except Exception as e:
                # Term is closed or invalid
                logging.error(_(
                    "Got exception trying to write_chars() to terminal %s"
                    % message['term']))
                logging.error(str(e))

        @require_auth
        def esc_opt_handler(self, chars):
            """
            Executes whatever function is registered matching the tuple returned by
            :func:`utils.process_opt_esc_sequence`.
            """
            logging.debug("esc_opt_handler(%s)" % repr(chars))
            plugin_name, text = process_opt_esc_sequence(chars)
            if plugin_name:
                try:
                    PLUGIN_ESC_HANDLERS[plugin_name](text, tws=self)
                except Exception as e:
                    logging.error(_(
                        "Got exception trying to execute plugin's optional ESC "
                        "sequence handler..."))
                    logging.error(str(e))

        def get_bell(self):
            """
            Sends the bell sound data to the client in in the form of a data::URI.
            """
            bell_path = os.path.join(GATEONE_DIR, 'static')
            bell_path = os.path.join(bell_path, 'bell.ogg')
            if os.path.exists(bell_path):
                try:
                    bell_data_uri = create_data_uri(bell_path)
                except MimeTypeFail:
                    bell_data_uri = fallback_bell
            else: # There's always the fallback
                bell_data_uri = fallback_bell
            mimetype = bell_data_uri.split(';')[0].split(':')[1]
            message = {
                'load_bell': {
                    'data_uri': bell_data_uri, 'mimetype': mimetype
                }
            }
            self.write_message(json_encode(message))

        def get_webworker(self):
            """
            Sends the text of our go_process.js to the client in order to get around
            the limitations of loading remote Web Worker URLs (for embedding Gate
            One into other apps).
            """
            static_url = os.path.join(GATEONE_DIR, "static")
            webworker_path = os.path.join(static_url, 'go_process.js')
            with open(webworker_path) as f:
                go_process = f.read()
            message = {'load_webworker': go_process}
            self.write_message(json_encode(message))

        def get_style(self, settings):
            """
            Sends the CSS stylesheets matching the properties specified in
            *settings* to the client.  *settings* must contain the following:

                * **container** - The element Gate One resides in (e.g. 'gateone')
                * **prefix** - The string being used to prefix all elements (e.g. 'go\_')

            *settings* may also contain any combination of the following:

                * **theme** - The name of the CSS theme to be retrieved.
                * **colors** - The name of the text color CSS scheme to be retrieved.
                * **plugins** - If true, will send all plugin .css files to the client.
            """
            logging.debug('get_style(%s)' % settings)
            out_dict = {'result': 'Success'}
            templates_path = os.path.join(GATEONE_DIR, 'templates')
            themes_path = os.path.join(templates_path, 'themes')
            colors_path = os.path.join(templates_path, 'term_colors')
            go_url = settings['go_url'] # Used to prefix the url_prefix
            if not go_url.endswith('/'):
                go_url += '/'
            container = settings["container"]
            prefix = settings["prefix"]
            theme = None
            if 'theme' in settings:
                theme = settings["theme"]
            colors = None
            if 'colors' in settings:
                colors = settings["colors"]
            plugins = None
            if 'plugins' in settings:
                plugins = settings["plugins"]
            if theme:
                # Setup our 256-color support CSS:
                colors_256 = ""
                for i in xrange(256):
                    fg = "#%s span.fx%s {color: #%s;}" % (
                        container, i, COLORS_256[i])
                    bg = "#%s span.bx%s {background-color: #%s;} " % (
                        container, i, COLORS_256[i])
                    fg_rev = "#%s span.reverse.fx%s {background-color: #%s; color: inherit;}" % (
                        container, i, COLORS_256[i])
                    bg_rev = "#%s span.reverse.bx%s {color: #%s; background-color: inherit;} " % (
                        container, i, COLORS_256[i])
                    colors_256 += "%s %s %s %s\n" % (fg, bg, fg_rev, bg_rev)
                colors_256 += "\n"
                theme_path = os.path.join(themes_path, "%s.css" % theme)
                theme_css = self.render_string(
                    theme_path,
                    container=container,
                    prefix=prefix,
                    colors_256=colors_256,
                    url_prefix=go_url
                )
                out_dict['theme'] = theme_css
            if colors:
                color_path = os.path.join(colors_path, "%s.css" % colors)
                colors_css = self.render_string(
                    color_path,
                    container=container,
                    prefix=prefix,
                    url_prefix=go_url
                )
                out_dict['colors'] = colors_css
            if plugins:
                # Build a dict of plugins
                out_dict['plugins'] = {}
                plugins_dir = os.path.join(GATEONE_DIR, 'plugins')
                for f in os.listdir(plugins_dir):
                    if os.path.isdir(os.path.join(plugins_dir, f)):
                        out_dict['plugins'][f] = ''
                # Add each plugin's CSS template(s) to its respective dict
                for plugin in list(out_dict['plugins'].keys()):
                    plugin_templates_path = os.path.join(
                        plugins_dir, plugin, 'templates')
                    if os.path.exists(plugin_templates_path):
                        for f in os.listdir(plugin_templates_path):
                            if f.endswith('.css'):
                                plugin_css_path = os.path.join(
                                    plugin_templates_path, f)
                                plugin_css = self.render_string(
                                    plugin_css_path,
                                    container=container,
                                    prefix=prefix,
                                    url_prefix=go_url
                                )
                                if bytes != str: # Python 3
                                    plugin_css = str(plugin_css, 'UTF-8')
                                out_dict['plugins'][plugin] += plugin_css
            self.write_message(json_encode({'load_style': out_dict}))

        # NOTE: This has been disabled for now.  It works OK but the problem is that
        # some plugin JS needs to load *before* the WebSocket is connected.  Might
        # ultimately be something that just won't work.  I'm still considering
        # ways I could take advantage of this though so I don't want to delete it
        # just yet.
        #def get_js(self):
            #"""
            #Sends all JavaScript files inside of plugins' 'static' directory to the
            #client.
            #"""
            #logging.debug('get_js()')
            #out_dict = {'result': 'Success', 'plugins': {}}
            ## Build a dict of plugins
            #plugins_dir = os.path.join(GATEONE_DIR, 'plugins')
            #for f in os.listdir(plugins_dir):
                #if os.path.isdir(os.path.join(plugins_dir, f)):
                    #out_dict['plugins'][f] = {}
            ## Add each found JS file to the respective dict
            #for plugin in out_dict['plugins'].keys():
                #plugin_static_path = os.path.join(plugins_dir, plugin, 'static')
                #if os.path.exists(plugin_static_path):
                    #for f in os.listdir(plugin_static_path):
                        #if f.endswith('.js'):
                            #print("f: %s" % f)
                            #plugin_js_path = os.path.join(plugin_static_path, f)
                            #with open(plugin_js_path) as js_file:
                                #plugin_js = js_file.read()
                                #out_dict['plugins'][plugin][f] = plugin_js
            #print("out_dict['plugins']: %s" % out_dict['plugins'])
            #self.write_message({'load_js': out_dict})

        def enumerate_themes(self):
            """
            Returns a JSON-encoded object containing the installed themes and text
            color schemes.
            """
            templates_path = os.path.join(GATEONE_DIR, 'templates')
            themes_path = os.path.join(templates_path, 'themes')
            colors_path = os.path.join(templates_path, 'term_colors')
            themes = os.listdir(themes_path)
            themes = [a.replace('.css', '') for a in themes]
            colors = os.listdir(colors_path)
            colors = [a.replace('.css', '') for a in colors]
            message = {'themes_list': {'themes': themes, 'colors': colors}}
            self.write_message(message)

        @require_auth
        def debug_terminal(self, term):
            """
            Prints the terminal's screen and renditions to stdout so they can be
            examined more closely.

            .. note:: Can only be called from a JavaScript console like so...

            .. code-block:: javascript

                GateOne.ws.send(JSON.stringify({'debug_terminal': *term*}));
            """
            termObj = SESSIONS[self.session][term]['multiplex'].term
            screen = termObj.screen
            renditions = termObj.renditions
            for i, line in enumerate(screen):
                # This gets rid of images:
                line = [a for a in line if len(a) == 1]
                print("%s:%s" % (i, "".join(line)))
                print(renditions[i])
            # Also check if there's anything that's uncollectable
            import gc
            gc.set_debug(gc.DEBUG_UNCOLLECTABLE|gc.DEBUG_OBJECTS)
            from pprint import pprint
            pprint(gc.garbage)
            print("gc.collect(): %s" % gc.collect())
            pprint(gc.garbage)
            print("SESSIONS...")
            pprint(SESSIONS)
            try:
                from pympler import asizeof
                print("screen size: %s" % asizeof.asizeof(screen))
                print("renditions size: %s" % asizeof.asizeof(renditions))
                print("Total term object size: %s" % asizeof.asizeof(termObj))
            except ImportError:
                pass # No biggie

    class ErrorHandler(tornado.web.RequestHandler):
        """
        Generates an error response with status_code for all requests.
        """
        def __init__(self, application, request, status_code):
            tornado.web.RequestHandler.__init__(self, application, request)
            self.set_status(status_code)

        def get_error_html(self, status_code, **kwargs):
            self.require_setting("static_url")
            if status_code in [404, 500, 503, 403]:
                filename = os.path.join(self.settings['static_url'], '%d.html' % status_code)
                if os.path.exists(filename):
                    f = open(filename, 'r')
                    data = f.read()
                    f.close()
                    return data
            import httplib
            return "<html><title>%(code)d: %(message)s</title>" \
                    "<body class='bodyErrorPage'>%(code)d: %(message)s</body></html>" % {
                "code": status_code,
                "message": httplib.responses[status_code],
            }

        def prepare(self):
            raise tornado.web.HTTPError(self._status_code)

    class Application(tornado.web.Application):
        def __init__(self, settings):
            """
            Setup our Tornado application...  Everything in *settings* will wind up
            in the Tornado settings dict so as to be accessible under self.settings.
            """
            global PLUGIN_WS_CMDS
            global PLUGIN_HOOKS
            global PLUGIN_ESC_HANDLERS
            global PLUGIN_AUTH_HOOKS
            global PLUGIN_TERM_HOOKS
            # Base settings for our Tornado app
            static_url = os.path.join(GATEONE_DIR, "static")
            tornado_settings = dict(
                cookie_secret=settings['cookie_secret'],
                static_url=static_url,
                static_url_prefix="%sstatic/" % settings['url_prefix'],
                gzip=True,
                login_url="%sauth" % settings['url_prefix']
            )
            # Make sure all the provided settings wind up in self.settings
            for k, v in settings.items():
                tornado_settings[k] = v
            # Setup the configured authentication type
            AuthHandler = NullAuthHandler # Default
            if 'auth' in settings and settings['auth']:
                if settings['auth'] == 'kerberos' and KerberosAuthHandler:
                    AuthHandler = KerberosAuthHandler
                elif settings['auth'] == 'pam' and PAMAuthHandler:
                    AuthHandler = PAMAuthHandler
                elif settings['auth'] == 'google':
                    AuthHandler = GoogleAuthHandler
                logging.info(_("Using %s authentication" % settings['auth']))
            else:
                logging.info(_("No authentication method configured. All users will "
                             "be ANONYMOUS"))
            docs_path = os.path.join(GATEONE_DIR, 'docs')
            docs_path = os.path.join(docs_path, 'build')
            docs_path = os.path.join(docs_path, 'html')
            url_prefix = settings['url_prefix']
            if not url_prefix.endswith('/'):
                # Make sure there's a trailing slash
                url_prefix = "%s/" % url_prefix
            # Make the / optional in the regex so it works with the @addslash
            # decorator.  e.g. "/whatever/" would become "/whatever/?"
            index_regex = "%s?" % url_prefix
            # Setup our URL handlers
            handlers = [
                (index_regex, MainHandler),
                # Override the default static handler to ensure the headers are set
                # to allow cross-origin requests.
                (r"%sstatic/(.*)" % url_prefix, StaticHandler, {
                    "path": static_url,
                }),
                (r"%sws" % url_prefix, TerminalWebSocket),
                (r"%sauth" % url_prefix, AuthHandler),
                (r"%scssrender" % url_prefix, PluginCSSTemplateHandler),
                (r"%scombined_js" % url_prefix, JSPluginsHandler),
                (r"%sdocs/(.*)" % url_prefix, tornado.web.StaticFileHandler, {
                    "path": docs_path,
                    "default_filename": "index.html"
                })
            ]
            # Hook up the hooks
            for plugin_name, hooks in PLUGIN_HOOKS.items():
                if 'Web' in hooks:
                    # Apply the plugin's Web handlers
                    fixed_hooks = []
                    if isinstance(hooks['Web'], (list, tuple)):
                        for h in hooks['Web']:
                            # h == (regex, Handler)
                            if not h[0].startswith(url_prefix): # Fix it
                                h = (url_prefix + h[0].lstrip('/'), h[1])
                                fixed_hooks.append(h)
                            else:
                                fixed_hooks.append(h)
                    else:
                        if not hooks['Web'][0].startswith(url_prefix): # Fix it
                            hooks['Web'] = (
                                url_prefix + hooks['Web'][0].lstrip('/'),
                                hooks['Web'][1]
                            )
                            fixed_hooks.append(hooks['Web'])
                        else:
                            fixed_hooks.append(hooks['Web'])
                    handlers.extend(fixed_hooks)
                if 'WebSocket' in hooks:
                    # Apply the plugin's WebSocket commands
                    PLUGIN_WS_CMDS.update(hooks['WebSocket'])
                if 'Escape' in hooks:
                    # Apply the plugin's Escape handler
                    PLUGIN_ESC_HANDLERS.update({plugin_name: hooks['Escape']})
                if 'Auth' in hooks:
                    # Apply the plugin's post-authentication functions
                    if isinstance(hooks['Auth'], list):
                        PLUGIN_AUTH_HOOKS.extend(hooks['Auth'])
                    else:
                        PLUGIN_AUTH_HOOKS.append(hooks['Auth'])
                if 'Terminal' in hooks:
                    # Apply the plugin's Terminal hooks (called by new_terminal)
                    PLUGIN_TERM_HOOKS.update(hooks['Terminal'])
            # This removes duplicate handlers for the same regex, allowing plugins
            # to override defaults:
            handlers = merge_handlers(handlers)
            # Include JS-only and CSS-only plugins (for logging purposes)
            js_plugins = [a.split('/')[2] for a in PLUGINS['js']]
            css_plugins = []
            for i in css_plugins:
                if '?' in i: # CSS Template
                    css_plugins.append(i.split('plugin=')[1].split('&')[0])
                else: # Static CSS file
                    css_plugins.append(i.split('/')[1])
            #css_plugins = [a.split('?')[1].split('&')[0].split('=')[1] for a in PLUGINS['css']]
            plugin_list = list(set(PLUGINS['py'] + js_plugins + css_plugins))
            plugin_list.sort() # So there's consistent ordering
            logging.info(_("Loaded plugins: %s" % ", ".join(plugin_list)))
            tornado.web.Application.__init__(self, handlers, **tornado_settings)

    def main():
        global _
        global user_locale
        # Default to using the shell's LANG variable as the locale
        try:
            default_locale = os.environ['LANG'].split('.')[0]
        except KeyError: # $LANG isn't set
            default_locale = "en_US"
        user_locale = locale.get(default_locale)
        # NOTE: The locale setting above is only for the --help messages.
        # Simplify the auth option help message
        auths = "none, api, google"
        if KerberosAuthHandler:
            auths += ", kerberos"
        if PAMAuthHandler:
            auths += ", pam"
        # Simplify the syslog_facility option help message
        facilities = list(FACILITIES.keys())
        facilities.sort()
        # Figure out the default origins
        default_origins = [
            'http://localhost',
            'https://localhost',
            'http://127.0.0.1',
            'https://127.0.0.1'
        ]
        # Used both http and https above to demonstrate that both are acceptable
        try:
            additional_origins = socket.gethostbyname_ex(socket.gethostname())
        except socket.gaierror:
            # Couldn't get any IPs from the hostname
            additional_origins = []
        for host in additional_origins:
            if isinstance(host, str):
                default_origins.append('https://%s' % host)
            else: # It's a list
                for _host in host:
                    default_origins.append('https://%s' % _host)
        default_origins = ";".join(default_origins)
        config_default = os.path.join(GATEONE_DIR, "server.conf")
        # TODO:  These configuration options are getting a bit unwiedly.  Move them into a separate file or something.  Might want to switch over to using optparse and/or ConfigParser as well.
        define("config",
            default=config_default,
            help=_(
                "Path to the config file.  Default: %s" % config_default),
            type=str
        )
        define(
            "debug",
            default=False,
            help=_("Enable debugging features such as auto-restarting when files "
                   "are modified.")
        )
        define("cookie_secret", # 45 chars is, "Good enough for me" (cookie joke =)
            default=None,
            help=_("Use the given 45-character string for cookie encryption."),
            type=str
        )
        define("command",
            # The default command assumes the SSH plugin is enabled
            default=GATEONE_DIR + "/plugins/ssh/scripts/ssh_connect.py -S "
                    r"'/tmp/gateone/%SESSION%/%SHORT_SOCKET%' --sshfp "
                    "-a '-oUserKnownHostsFile=%USERDIR%/%USER%/ssh/known_hosts'",
            help=_("Run the given command when a user connects (e.g. '/bin/login')."
                   ),
            type=str
        )
        define("address",
            default="",
            help=_("Run on the given address.  Default is all addresses (IPv6 "
                   "included).  Multiple address can be specified using a semicolon"
                   " as a separator (e.g. '127.0.0.1;::1;10.1.1.100')."),
            type=str)
        define("port", default=443, help=_("Run on the given port."), type=int)
        define(
            "enable_unix_socket",
            default=False,
            help=_("Enable Unix socket support."),
            type=bool)
        define(
            "unix_socket_path",
            default="/var/run/gateone.sock",
            help=_("Path to the Unix socket (if --enable_unix_socket=True)."),
            type=str)
        # Please only use this if Gate One is running behind something with SSL:
        define(
            "disable_ssl",
            default=False,
            help=_("If enabled, Gate One will run without SSL (generally not a "
                   "good idea).")
        )
        define(
            "certificate",
            default="certificate.pem",
            help=_("Path to the SSL certificate.  Will be auto-generated if none is"
                   " provided."),
            type=str
        )
        define(
            "keyfile",
            default="keyfile.pem",
            help=_("Path to the SSL keyfile.  Will be auto-generated if none is"
                   " provided."),
            type=str
        )
        define(
            "ca_certs",
            default=None,
            help=_("Path to a file containing any number of concatenated CA "
                   "certificates in PEM format.  They will be used to authenticate "
                   "clients if the 'ssl_auth' option is set to 'optional' or "
                   "'required'."),
            type=str
        )
        define(
            "ssl_auth",
            default='none',
            help=_("Enable the use of client SSL (X.509) certificates as a "
                   "secondary authentication factor (the configured 'auth' type "
                   "will come after SSL auth).  May be one of 'none', 'optional', "
                   "or 'required'.  NOTE: Only works if the 'ca_certs' option is "
                   "configured."),
            type=str
        )
        define(
            "user_dir",
            default=os.path.join(GATEONE_DIR, "users"),
            help=_("Path to the location where user files will be stored."),
            type=str
        )
        define(
            "session_dir",
            default="/tmp/gateone",
            help=_("Path to the location where session information will be stored."),
            type=str
        )
        define(
            "session_logging",
            default=True,
            help=_("If enabled, logs of user sessions will be saved in "
                   "<user_dir>/<user>/logs.  Default: Enabled")
        )
        define( # This is an easy way to support cetralized logging
            "syslog_session_logging",
            default=False,
            help=_("If enabled, logs of user sessions will be written to syslog.")
        )
        define(
            "syslog_facility",
            default="daemon",
            help=_("Syslog facility to use when logging to syslog (if "
                   "syslog_session_logging is enabled).  Must be one of: %s."
                   "  Default: daemon" % ", ".join(facilities)),
            type=str
        )
        define(
            "syslog_host",
            default=None,
            help=_("Remote host to send syslog messages to if syslog_logging is "
                   "enabled.  Default: None (log to the local syslog daemon "
                   "directly).  NOTE:  This setting is required on platforms that "
                   "don't include Python's syslog module."),
            type=str
        )
        define(
            "session_timeout",
            default="5d",
            help=_("Amount of time that a session is allowed to idle before it is "
            "killed.  Accepts <num>X where X could be one of s, m, h, or d for "
            "seconds, minutes, hours, and days.  Default is '5d' (5 days)."),
            type=str
        )
        define(
            "new_api_key",
            default=False,
            help=_("Generate a new API key that an external application can use to "
                   "embed Gate One."),
        )
        define(
            "auth",
            default=None,
            help=_("Authentication method to use.  Valid options are: %s" % auths),
            type=str
        )
        # This is to prevent replay attacks.  Gate One only keeps a "working memory"
        # of API auth objects for this amount of time.  So if the Gate One server is
        # restarted we don't have to write them to disk as anything older than this
        # setting will be invalid (no need to check if it has already been used).
        define(
            "api_timestamp_window",
            default="30s", # 30 seconds
            help=_(
                "How long before an API authentication object becomes invalid.  "
                "Default is '30s' (30 seconds)."),
            type=str
        )
        define(
            "sso_realm",
            default=None,
            help=_("Kerberos REALM (aka DOMAIN) to use when authenticating clients."
                   " Only relevant if Kerberos authentication is enabled."),
            type=str
        )
        define(
            "sso_service",
            default='HTTP',
            help=_("Kerberos service (aka application) to use. Defaults to HTTP. "
                   "Only relevant if Kerberos authentication is enabled."),
            type=str
        )
        define(
            "pam_realm",
            default=os.uname()[1],
            help=_("Basic auth REALM to display when authenticating clients.  "
            "Default: hostname.  "
            "Only relevant if PAM authentication is enabled."),
            # NOTE: This is only used to show the user a REALM at the basic auth
            #       prompt and as the name in the GATEONE_DIR+'/users' directory
            type=str
        )
        define(
            "pam_service",
            default='login',
            help=_("PAM service to use.  Defaults to 'login'. "
                   "Only relevant if PAM authentication is enabled."),
            type=str
        )
        define(
            "embedded",
            default=False,
            help=_("Doesn't do anything (yet).")
        )
        define(
            "dtach",
            default=True,
            help=_("Wrap terminals with dtach. Allows sessions to be resumed even "
                   "if Gate One is stopped and started (which is a sweet feature).")
        )
        define(
            "kill",
            default=False,
            help=_("Kill any running Gate One terminal processes including dtach'd "
                   "processes.")
        )
        define(
            "locale",
            default=default_locale,
            help=_("The locale (e.g. pt_PT) Gate One should use for translations."
                 "  If not provided, will default to $LANG (which is '%s' in your "
                 "current shell), or en_US if not set."
                 % os.environ.get('LANG', 'not set').split('.')[0]),
            type=str
        )
        define("js_init",
            default="",
            help=_("A JavaScript object (string) that will be used when running "
                   "GateOne.init() inside index.html.  "
                   "Example: --js_init=\"{scheme: 'white'}\" would result in "
                   "GateOne.init({scheme: 'white'})"),
            type=str
        )
        define(
            "https_redirect",
            default=False,
            help=_("If enabled, a separate listener will be started on port 80 that"
                   " redirects users to the configured port using HTTPS.")
        )
        define(
            "url_prefix",
            default="/",
            help=_("An optional prefix to place before all Gate One URLs. e.g. "
                   "'/gateone/'.  Use this if Gate One will be running behind a "
                   "reverse proxy where you want it to be located at some sub-"
                   "URL path."),
            type=str
        )
        define(
            "origins",
            default=default_origins,
            help=_("A semicolon-separated list of origins you wish to allow access "
                   "to your Gate One server over the WebSocket.  This value must "
                   "contain the hostnames and FQDNs (e.g. https://foo;"
                   "https://foo.bar;) users will use to connect to your Gate One "
                   "server as well as the hostnames/FQDNs of any sites that will be"
                   " embedding Gate One. Here's the default on your system: '%s'. "
                   "Alternatively, '*' may be  specified to allow access from "
                   "anywhere." % default_origins),
            type=str
        )
        define(
            "pid_file",
            default="/var/run/gateone.pid",
            help=_(
                "Define the path to the pid file.  Default: /var/run/gateone.pid"),
            type=str
        )
        define(
            "uid",
            default=str(os.getuid()),
            help=_(
                "Drop privileges and run Gate One as this user/uid."),
            type=str
        )
        define(
            "gid",
            default=str(os.getgid()),
            help=_(
                "Drop privileges and run Gate One as this group/gid."),
            type=str
        )
        define(
            "session_logs_max_age",
            default="30d",
            help=_("Maximum amount of length of time to keep any given session log "
                   "before it is removed."),
            type=str
        )
        # Before we do anythong else, load plugins and assign their hooks.  This
        # allows plugins to add their own define() statements/options.
        imported = load_plugins(PLUGINS['py'])
        new_conf = False # Used below to tell the user that a server.conf was
                         # generated in their chosen language.
        for plugin in imported:
            try:
                PLUGIN_HOOKS.update({plugin.__name__: plugin.hooks})
            except AttributeError:
                pass # No hooks--probably just a supporting .py file.
        # We have to parse the command line options so we can check for a config to
        # load.  The config will then be loaded--overriding command line options but
        # this won't be a problem since we'll re-parse the command line options
        # further down which will subsequently override the config.
        tornado.options.parse_command_line()
        if os.path.exists(options.config):
            tornado.options.parse_config_file(options.config)
        # If you want any missing config file entries re-generated just delete the
        # cookie_secret line...
        if not options.cookie_secret:
            # Generate a default server.conf with a random cookie secret
            # NOTE: This will also generate a new server.conf if it is missing.
            logging.info(_(
              "%s not found or missing cookie_secret.  A new one will be generated."
              % options.config))
            config_defaults = {}
            for key, value in options.items():
                if value._value != None:
                    config_defaults.update({key: value._value})
                else:
                    config_defaults.update({key: value.default})
            # A few config defaults need special handling
            del config_defaults['kill'] # This shouldn't be in server.conf
            del config_defaults['help'] # Neither should this
            del config_defaults['new_api_key'] # Ditto
            del config_defaults['config'] # Re-ditto
            config_defaults.update({'cookie_secret': generate_session_id()})
            # NOTE: The next four options are specific to the Tornado framework
            config_defaults.update({'log_file_max_size': 100 * 1024 * 1024}) # 100MB
            config_defaults.update({'log_file_num_backups': 10})
            config_defaults.update({'log_to_stderr': False})
            if options.log_file_prefix == None:
                web_log_path = os.path.join(GATEONE_DIR, 'logs')
                config_defaults.update({
                    'log_file_prefix': os.path.join(web_log_path, 'webserver.log')})
            else:
                web_log_path = os.path.split(options.log_file_prefix)[0]
            if not os.path.exists(web_log_path):
                mkdir_p(web_log_path)
            if not os.path.exists(config_defaults['log_file_prefix']):
                open(config_defaults['log_file_prefix'], 'w').write('')
            config = open(options.config, "w")
            for key, value in config_defaults.items():
                if isinstance(value, basestring):
                    config.write('%s = "%s"\n' % (key, value))
                else:
                    config.write('%s = %s\n' % (key, value))
            config.close()
            tornado.options.parse_config_file(options.config)
        tornado.options.parse_command_line()
        # Change the uid/gid strings into integers
        try:
            uid = int(options.uid)
        except ValueError:
            # Assume it's a username and grab its uid
            uid = pwd.getpwnam(options.uid).pw_uid
        try:
            gid = int(options.gid)
        except ValueError:
            # Assume it's a group name and grab its gid
            gid = grp.getgrnam(options.gid).gr_gid
        if not os.path.exists(options.user_dir): # Make our user_dir
            try:
                mkdir_p(options.user_dir)
            except OSError:
                logging.error(_(
                    "Error: Gate One could not create %s.  Please ensure that user,"
                    " %s has permission to create this directory or create it "
                    "yourself and make user, %s its owner." % (options.user_dir,
                    repr(os.getlogin()), repr(os.getlogin()))))
                sys.exit(1)
            # If we could create it we should be able to adjust its permissions:
            os.chmod(options.user_dir, 0o770)
        if os.stat(options.user_dir).st_uid != uid:
            # Try correcting this first
            try:
                recursive_chown(options.user_dir, uid, gid)
            except ChownError as e:
                logging.error(e)
                sys.exit(1)
        if not os.path.exists(options.session_dir): # Make our session_dir
            try:
                mkdir_p(options.session_dir)
            except OSError:
                logging.error(_(
                    "Error: Gate One could not create %s.  Please ensure that user,"
                    " %s has permission to create this directory or create it "
                    "yourself and make user, %s its owner." % (options.session_dir,
                    repr(os.getlogin()), repr(os.getlogin()))))
                sys.exit(1)
            os.chmod(options.session_dir, 0o770)
        if os.stat(options.session_dir).st_uid != uid:
            # Try correcting it
            try:
                recursive_chown(options.session_dir, uid, gid)
            except ChownError as e:
                logging.error(e)
                sys.exit(1)
        # Re-do the locale in case the user supplied something as --locale
        user_locale = locale.get(options.locale)
        _ = user_locale.translate # Also replaces our wrapper so no more .encode()
        # Create the log dir if not already present (NOTE: Assumes we're root)
        log_dir = os.path.split(options.log_file_prefix)[0]
        if not os.path.exists(log_dir):
            try:
                mkdir_p(log_dir)
            except OSError:
                logging.error(_("\x1b[1;31mERROR:\x1b[0m Could not create %s for "
                      "log_file_prefix: %s" % (log_dir, options.log_file_prefix)))
                logging.error(_("You probably want to change this option, run Gate "
                      "One as root, or create that directory and give the proper "
                      "user ownership of it."))
                sys.exit(1)
        if os.stat(log_dir).st_uid != uid:
            # Try to correct it
            try:
                recursive_chown(log_dir, uid, gid)
            except ChownError as e:
                logging.error(e)
                sys.exit(1)
        if options.kill:
            # Kill all running dtach sessions (associated with Gate One anyway)
            killall(options.session_dir)
            sys.exit(0)
        if options.new_api_key:
            # Generate a new API key for an application to use
            api_key = generate_session_id()
            # Generate a new secret
            secret = generate_session_id()
            # Save it
            server_conf = ""
            with open(options.config) as f:
                existing = ""
                for line in f.readlines():
                    if line.startswith("api_keys"):
                        existing = line.split('=')[1].strip().strip('"').strip("'")
                        existing += ",%s:%s" % (api_key, secret)
                        line = 'api_keys = "%s"\n' % existing
                    server_conf += line
                if not existing:
                    server_conf += 'api_keys = "%s:%s"\n' % (api_key, secret)
            open(os.path.join(options.config), 'w').write(server_conf)
            logging.info(_("A new API key has been generated: %s" % api_key))
            logging.info(_("This key can now be used to embed Gate One into other "
                    "applications."))
            sys.exit(0)
        # Set our CMD variable to tell the multiplexer which command to execute
        global CMD
        CMD = options.command
        # Set our global session timeout
        global TIMEOUT
        TIMEOUT = convert_to_timedelta(options.session_timeout)
        # Make sure dtach is available and if not, set dtach=False
        if not which('dtach'):
            logging.warning(
                _("dtach command not found.  dtach support has been disabled."))
            options.dtach = False
        # Turn our API keys into a dict
        api_keys = {}
        with open(options.config) as f:
            for line in f.readlines():
                if line.startswith("api_keys"):
                    values = line.split('=')[1].strip().strip('"').strip("'")
                    pairs = values.split(',')
                    for pair in pairs:
                        api_key, secret = pair.split(':')
                        api_keys.update({api_key: secret})
        # Fix the url_prefix if the user forgot the trailing slash
        if not options.url_prefix.endswith('/'):
            options.url_prefix += '/'
        # Convert the origins into a list of http:// or https:// origins
        origins = options.origins.lower() # Origins are case-insensitive
        real_origins = origins.split(';')
        if options.origins == '*':
            real_origins = ['*']
        logging.info("Connections to this server will be allowed from the following"
                     " origins: '%s'" % " ".join(real_origins))
        # Define our Application settings
        api_timestamp_window = convert_to_timedelta(options.api_timestamp_window)
        app_settings = {
            'gateone_dir': GATEONE_DIR, # Only here so plugins can reference it
            'debug': options.debug,
            'cookie_secret': options.cookie_secret,
            'auth': none_fix(options.auth),
            'api_timestamp_window': api_timestamp_window,
            'embedded': options.embedded,
            'js_init': options.js_init,
            'user_dir': options.user_dir,
            'logging': options.logging, # For reference, really
            'session_dir': options.session_dir,
            'session_logging': options.session_logging,
            'syslog_session_logging': options.syslog_session_logging,
            'syslog_facility': options.syslog_facility,
            'syslog_host': options.syslog_host,
            'dtach': options.dtach,
            'sso_realm': options.sso_realm,
            'sso_service': options.sso_service,
            'pam_realm': options.pam_realm,
            'pam_service': options.pam_service,
            'locale': options.locale,
            'api_keys': api_keys,
            'url_prefix': options.url_prefix,
            'origins': real_origins,
            'pid_file': options.pid_file
        }
        # Check to make sure we have a certificate and keyfile and generate fresh
        # ones if not.
        if not os.path.exists(options.keyfile):
            logging.info(_("No SSL private key found.  One will be generated."))
            gen_self_signed_ssl()
        if not os.path.exists(options.certificate):
            logging.info(_("No SSL certificate found.  One will be generated."))
            gen_self_signed_ssl()
        # Setup static file links for plugins (if any)
        static_dir = os.path.join(GATEONE_DIR, "static")
        # Verify static_dir's permissions
        if os.stat(static_dir).st_uid != uid:
            # Try correcting it
            try: # Just os.chown on this one (recursive could be bad)
                os.chown(static_dir, uid, gid)
            except OSError:
                logging.error(_(
                    "Error: Gate One does not have permission to write to %s.  "
                    "Please ensure that user, %s has write permission to the "
                    "directory." % (
                    static_dir, os.getlogin())))
                sys.exit(1)
        plugin_dir = os.path.join(GATEONE_DIR, "plugins")
        templates_dir = os.path.join(GATEONE_DIR, "templates")
        combined_plugins = os.path.join(static_dir, "combined_plugins.js")
        # Remove the combined_plugins.js (it will get auto-recreated)
        if os.path.exists(combined_plugins):
            os.remove(combined_plugins)
        create_plugin_links(static_dir, templates_dir, plugin_dir)
        # When options.logging=="debug" it will display all user's keystrokes so
        # make sure we warn about this.
        if options.logging == "debug":
            logging.warning(_(
                "Logging is set to DEBUG.  Be aware that this will record the "
                "keystrokes of all users.  Don't be evil!"))
        if options.ssl_auth.lower() == 'required':
            # Convert to an integer using the ssl module
            cert_reqs = ssl.CERT_REQUIRED
        elif options.ssl_auth.lower() == 'optional':
            cert_reqs = ssl.CERT_OPTIONAL
        else:
            cert_reqs = ssl.CERT_NONE
        # Instantiate our Tornado web server
        ssl_options = {
            "certfile": options.certificate,
            "keyfile": options.keyfile,
            "ca_certs": options.ca_certs,
            "cert_reqs": cert_reqs
        }
        if options.disable_ssl:
            ssl_options = None
        https_server = tornado.httpserver.HTTPServer(
            Application(settings=app_settings), ssl_options=ssl_options)
        https_redirect = tornado.web.Application(
            [(r".*", HTTPSRedirectHandler),],
            port=options.port,
            url_prefix=options.url_prefix
        )
        tornado.web.ErrorHandler = ErrorHandler
        try: # Start your engines!
            if options.enable_unix_socket:
                https_server.add_socket(
                    tornado.netutil.bind_unix_socket(options.unix_socket_path))
                logging.info(_("Listening on Unix socket '{socketpath}'".format(
                    socketpath=options.unix_socket_path)))
            address = none_fix(options.address)
            if address:
                for addr in address.split(';'):
                    if addr: # Listen on all given addresses
                        if options.https_redirect:
                            logging.info(_(
                                "http://{addr}:80/ will be redirected to...".format(
                                    addr=addr)
                            ))
                            https_redirect.listen(port=80, address=addr)
                        logging.info(_(
                            "Listening on https://{address}:{port}/".format(
                                address=addr, port=options.port)
                        ))
                        https_server.listen(port=options.port, address=addr)
            elif address == '':
                # Listen on all addresses (including IPv6)
                if options.https_redirect:
                    logging.info(_("http://*:80/ will be redirected to..."))
                    https_redirect.listen(port=80, address="")
                logging.info(_(
                    "Listening on https://*:{port}/".format(port=options.port)))
                https_server.listen(port=options.port, address="")
            # NOTE:  To have Gate One *not* listen on a TCP/IP address you may set
            #        address=None
            write_pid(options.pid_file)
            pid = read_pid(options.pid_file)
            logging.info(_("Process running with pid " + pid))
            # Check to see what group owns /dev/pts and use that for supl_groups
            # First we have to make sure there's at least one pty present
            tempfd1, tempfd2 = pty.openpty()
            # Now check the owning group (doesn't matter which one so we use 0)
            tty_gid = os.stat('/dev/ptmx').st_gid
            # Close our temmporary pty/fds so we're not wasting them
            os.close(tempfd1)
            os.close(tempfd2)
            if uid != os.getuid():
                drop_privileges(uid, gid, [tty_gid])
            # Make sure that old logs get cleaned up
            global CLEANER
            if not CLEANER:
                interval = 5*60*1000 # Check every 5 minutes
                max_age = convert_to_timedelta(options.session_logs_max_age)
                cleaner = partial(
                    cleanup_session_logs,
                    options.user_dir,
                    max_age)
                CLEANER = tornado.ioloop.PeriodicCallback(cleaner, interval)
                CLEANER.start()
            tornado.ioloop.IOLoop.instance().start()
        except KeyboardInterrupt: # ctrl-c
            logging.info(_("Caught KeyboardInterrupt.  Killing sessions..."))
        finally:
            tornado.ioloop.IOLoop.instance().stop()
            remove_pid(options.pid_file)
            logging.info(_("pid file removed."))
            if not options.dtach:
                # If we're not using dtach play it safe by cleaning up any leftover
                # processes.  When passwords are used with the ssh_conenct.py script
                # it runs os.setsid() on the child process which means it won't die
                # when Gate One is closed.  This is primarily to handle that
                # specific situation.
                killall(options.session_dir)

    if __name__ == "__main__":
        main()

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