#!/usr/bin/env python

# ***********************IMPORTANT NMAP LICENSE TERMS************************
# *                                                                         *
# * The Nmap Security Scanner is (C) 1996-2013 Insecure.Com LLC. Nmap is    *
# * also a registered trademark of Insecure.Com LLC.  This program is free  *
# * software; you may redistribute and/or modify it under the terms of the  *
# * GNU General Public License as published by the Free Software            *
# * Foundation; Version 2 ("GPL"), BUT ONLY WITH ALL OF THE CLARIFICATIONS  *
# * AND EXCEPTIONS DESCRIBED HEREIN.  This guarantees your right to use,    *
# * modify, and redistribute this software under certain conditions.  If    *
# * you wish to embed Nmap technology into proprietary software, we sell    *
# * alternative licenses (contact sales@nmap.com).  Dozens of software      *
# * vendors already license Nmap technology such as host discovery, port    *
# * scanning, OS detection, version detection, and the Nmap Scripting       *
# * Engine.                                                                 *
# *                                                                         *
# * Note that the GPL places important restrictions on "derivative works",  *
# * yet it does not provide a detailed definition of that term.  To avoid   *
# * misunderstandings, we interpret that term as broadly as copyright law   *
# * allows.  For example, we consider an application to constitute a        *
# * derivative work for the purpose of this license if it does any of the   *
# * following with any software or content covered by this license          *
# * ("Covered Software"):                                                   *
# *                                                                         *
# * o Integrates source code from Covered Software.                         *
# *                                                                         *
# * o Reads or includes copyrighted data files, such as Nmap's nmap-os-db   *
# * or nmap-service-probes.                                                 *
# *                                                                         *
# * o Is designed specifically to execute Covered Software and parse the    *
# * results (as opposed to typical shell or execution-menu apps, which will *
# * execute anything you tell them to).                                     *
# *                                                                         *
# * o Includes Covered Software in a proprietary executable installer.  The *
# * installers produced by InstallShield are an example of this.  Including *
# * Nmap with other software in compressed or archival form does not        *
# * trigger this provision, provided appropriate open source decompression  *
# * or de-archiving software is widely available for no charge.  For the    *
# * purposes of this license, an installer is considered to include Covered *
# * Software even if it actually retrieves a copy of Covered Software from  *
# * another source during runtime (such as by downloading it from the       *
# * Internet).                                                              *
# *                                                                         *
# * o Links (statically or dynamically) to a library which does any of the  *
# * above.                                                                  *
# *                                                                         *
# * o Executes a helper program, module, or script to do any of the above.  *
# *                                                                         *
# * This list is not exclusive, but is meant to clarify our interpretation  *
# * of derived works with some common examples.  Other people may interpret *
# * the plain GPL differently, so we consider this a special exception to   *
# * the GPL that we apply to Covered Software.  Works which meet any of     *
# * these conditions must conform to all of the terms of this license,      *
# * particularly including the GPL Section 3 requirements of providing      *
# * source code and allowing free redistribution of the work as a whole.    *
# *                                                                         *
# * As another special exception to the GPL terms, Insecure.Com LLC grants  *
# * permission to link the code of this program with any version of the     *
# * OpenSSL library which is distributed under a license identical to that  *
# * listed in the included docs/licenses/OpenSSL.txt file, and distribute   *
# * linked combinations including the two.                                  *
# *                                                                         *
# * Any redistribution of Covered Software, including any derived works,    *
# * must obey and carry forward all of the terms of this license, including *
# * obeying all GPL rules and restrictions.  For example, source code of    *
# * the whole work must be provided and free redistribution must be         *
# * allowed.  All GPL references to "this License", are to be treated as    *
# * including the terms and conditions of this license text as well.       *
# *                                                                         *
# * Because this license imposes special exceptions to the GPL, Covered     *
# * Work may not be combined (even as part of a larger work) with plain GPL *
# * software.  The terms, conditions, and exceptions of this license must   *
# * be included as well.  This license is incompatible with some other open *
# * source licenses as well.  In some cases we can relicense portions of    *
# * Nmap or grant special permissions to use it in other open source        *
# * software.  Please contact fyodor@nmap.org with any such requests.       *
# * Similarly, we don't incorporate incompatible open source software into  *
# * Covered Software without special permission from the copyright holders. *
# *                                                                         *
# * If you have any questions about the licensing restrictions on using     *
# * Nmap in other works, are happy to help.  As mentioned above, we also    *
# * offer alternative license to integrate Nmap into proprietary            *
# * applications and appliances.  These contracts have been sold to dozens  *
# * of software vendors, and generally include a perpetual license as well  *
# * as providing for priority support and updates.  They also fund the      *
# * continued development of Nmap.  Please email sales@nmap.com for further *
# * information.                                                            *
# *                                                                         *
# * If you have received a written license agreement or contract for        *
# * Covered Software stating terms other than these, you may choose to use  *
# * and redistribute Covered Software under those terms instead of these.   *
# *                                                                         *
# * Source is provided to this software because we believe users have a     *
# * right to know exactly what a program is going to do before they run it. *
# * This also allows you to audit the software for security holes (none     *
# * have been found so far).                                                *
# *                                                                         *
# * Source code also allows you to port Nmap to new platforms, fix bugs,    *
# * and add new features.  You are highly encouraged to send your changes   *
# * to the dev@nmap.org mailing list for possible incorporation into the    *
# * main distribution.  By sending these changes to Fyodor or one of the    *
# * Insecure.Org development mailing lists, or checking them into the Nmap  *
# * source code repository, it is understood (unless you specify otherwise) *
# * that you are offering the Nmap Project (Insecure.Com LLC) the           *
# * unlimited, non-exclusive right to reuse, modify, and relicense the      *
# * code.  Nmap will always be available Open Source, but this is important *
# * because the inability to relicense code has caused devastating problems *
# * for other Free Software projects (such as KDE and NASM).  We also       *
# * occasionally relicense the code to third parties as discussed above.    *
# * If you wish to specify special license conditions of your               *
# * contributions, just say so when you send them.                          *
# *                                                                         *
# * This program is distributed in the hope that it will be useful, but     *
# * WITHOUT ANY WARRANTY; without even the implied warranty of              *
# * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the Nmap      *
# * license file for more details (it's in a COPYING file included with     *
# * Nmap, and also available from https://svn.nmap.org/nmap/COPYING         *
# *                                                                         *
# ***************************************************************************/

# This module is responsible for interface present under "Scripting" tab.

import gobject
import gtk
import sys
import tempfile
import re
import xml.sax

from zenmapGUI.higwidgets.higwindows import HIGWindow
from zenmapGUI.higwidgets.higboxes import HIGVBox, HIGHBox, HIGSpacer, hig_box_space_holder
from zenmapGUI.higwidgets.higlabels import HIGSectionLabel, HIGEntryLabel
from zenmapGUI.higwidgets.higscrollers import HIGScrolledWindow
from zenmapGUI.higwidgets.higtextviewers import HIGTextView
from zenmapGUI.higwidgets.higbuttons import HIGButton
from zenmapGUI.higwidgets.higtables import HIGTable
from zenmapGUI.higwidgets.higdialogs import HIGAlertDialog, HIGDialog
from zenmapCore.ScriptMetadata import *
from zenmapCore.ScriptArgsParser import parse_script_args_dict
from zenmapCore.NmapCommand import NmapCommand
from zenmapCore.NmapOptions import NmapOptions
from zenmapCore.Paths import Path
import zenmapCore.NSEDocParser
import zenmapGUI.FileChoosers
from zenmapCore.UmitConf import PathsConfig
from zenmapCore.UmitLogging import log
from zenmapCore.Name import APP_NAME

paths_config = PathsConfig()

def text_buffer_insert_nsedoc(buf, nsedoc):
    """Inserts NSEDoc at the end of the buffer, with markup turned into proper
    tags."""
    if not buf.tag_table.lookup("NSEDOC_CODE_TAG"):
        buf.create_tag("NSEDOC_CODE_TAG", font = "Monospace")
    for event in zenmapCore.NSEDocParser.nsedoc_parse(nsedoc):
        if event.type == "paragraph_start":
            buf.insert(buf.get_end_iter(), "\n")
        elif event.type == "paragraph_end":
            buf.insert(buf.get_end_iter(), "\n")
        elif event.type == "list_start":
            buf.insert(buf.get_end_iter(), "\n")
        elif event.type == "list_end":
            pass
        elif event.type == "list_item_start":
            buf.insert(buf.get_end_iter(), u"\u2022\u00a0") # bullet nbsp
        elif event.type == "list_item_end":
            buf.insert(buf.get_end_iter(), "\n")
        elif event.type == "text":
            buf.insert(buf.get_end_iter(), event.text)
        elif event.type == "code":
            buf.insert_with_tags_by_name(buf.get_end_iter(), event.text, "NSEDOC_CODE_TAG")

class ScriptHelpXMLContentHandler (xml.sax.handler.ContentHandler):
    """A very simple parser for --script-help XML output. This could extract
    other information like categories and description, but all it gets is
    filenames. (ScriptMetadata gets the other information.)"""
    def __init__(self):
        self.script_filenames = []
        self.scripts_dir = None
        self.nselib_dir = None

    def startElement(self, name, attrs):
        if name == u"directory":
            if not attrs.has_key(u"name"):
                raise ValueError(u"\"directory\" element did not have \"name\" attribute")
            dirname = attrs[u"name"]
            if not attrs.has_key(u"path"):
                raise ValueError(u"\"directory\" element did not have \"path\" attribute")
            path = attrs[u"path"]
            if dirname == u"scripts":
                self.scripts_dir = path
            elif dirname == u"nselib":
                self.nselib_dir = path
            else:
                # Ignore.
                pass
        elif name == u"script":
            if not attrs.has_key(u"filename"):
                raise ValueError(u"\"script\" element did not have \"filename\" attribute")
            self.script_filenames.append(attrs[u"filename"])

    @staticmethod
    def parse_nmap_script_help(f):
        parser = xml.sax.make_parser()
        handler = ScriptHelpXMLContentHandler()
        parser.setContentHandler(handler)
        parser.parse(f)
        return handler

class ScriptInterface:
    # Timeout, in milliseconds, after the user stops typing and we update the
    # interface from --script.
    SCRIPT_LIST_DELAY = 500
    # Timeout, in milliseconds, between polls of the Nmap subprocess.
    NMAP_DELAY = 200

    def __init__(self,root_tabs,ops,update_command,help_buf):
        self.hmainbox = HIGHBox(False,0)
        self.notscripttab  = False # to show profile editor that it is a script tab
        self.nmap_process = None
        self.script_list_timeout_id = None
        self.nmap_timeout_id = None
        self.chk_nmap_timeout_id = None
        self.script_file_chooser = None
        self.ops = ops
        self.update_command = update_command
        self.help_buf = help_buf
        self.arg_values = {}
        self.current_arguments = []
        self.set_help_texts()
        self.prev_script_spec = None
        self.focussedentry = None

        self.liststore = gtk.ListStore(str, "gboolean", object)

        self.file_liststore = gtk.ListStore(str, "gboolean")

        # Arg name, arg value, (name, desc) tuple.
        self.arg_liststore = gtk.ListStore(str, str, object)

        # This is what is shown initially. After the initial Nmap run to get the
        # list of script is finished, this will be replaced with a TreeView
        # showing the scripts or an error message.
        self.script_list_container = gtk.VBox()
        self.script_list_container.pack_start(self.make_please_wait_widget())
        self.hmainbox.pack_start(self.script_list_container, False, False, 0)

        self.nmap_error_widget = gtk.Label(_("""\
There was an error getting the list of scripts from Nmap. Try upgrading Nmap.\
"""))
        self.nmap_error_widget.set_line_wrap(True)
        self.nmap_error_widget.show_all()

        self.script_list_widget = self.make_script_list_widget()
        self.script_list_widget.show_all()

        vbox = HIGVBox(False, 5)
        vbox.pack_start(self.make_description_widget(), True, True, 0)
        vbox.pack_start(self.make_arguments_widget(), True, True, 0)
        self.hmainbox.pack_end(vbox, True, True, 0)

        self.update_argument_values(self.ops["--script-args"])

        # Start the initial backgrounded Nmap run to get the list of all
        # available scripts.
        self.get_script_list("all", self.initial_script_list_cb)

    def get_script_list(self, rules, callback):
        """Start an Nmap subprocess in the background with
        "--script-help=<rules> -oX -", and set it up to call the given callback when
        finished."""

        ops = NmapOptions()
        ops.executable = paths_config.nmap_command_path
        ops["--script-help"] = rules
        ops["-oX"] = "-"
        command_string = ops.render_string()
        # Separate stderr to avoid breaking XML parsing with "Warning: File
        # ./nse_main.lua exists, but Nmap is using...".
        stderr = tempfile.TemporaryFile(mode = "rb", prefix = APP_NAME + "-script-help-stderr-")
        log.debug("Script interface: running %s" % repr(command_string))
        nmap_process = NmapCommand(command_string)
        try:
            nmap_process.run_scan(stderr = stderr)
        except Exception, e:
            callback(False, None)
            stderr.close()
            return
        stderr.close()

        self.script_list_widget.set_sensitive(False)

        gobject.timeout_add(self.NMAP_DELAY, self.script_list_timer_callback, nmap_process, callback)

    def script_list_timer_callback(self, process, callback):
        try:
            status = process.scan_state()
        except:
            status = None
        log.debug("Script interface: script_list_timer_callback %s" % repr(status))

        if status == True:
            # Still running, schedule this timer to check again.
            return True

        self.script_list_widget.set_sensitive(True)

        if status == False:
            # Finished with success.
            callback(True, process)
        else:
            # Finished with error.
            callback(False, process)

    def initial_script_list_cb(self, status, process):
        log.debug("Script interface: initial_script_list_cb %s" % repr(status))
        for child in self.script_list_container.get_children():
            self.script_list_container.remove(child)
        if status and self.handle_initial_script_list_output(process):
            self.script_list_container.pack_start(self.script_list_widget)
        else:
            self.script_list_container.pack_start(self.nmap_error_widget)

    def handle_initial_script_list_output(self, process):
        process.stdout_file.seek(0)
        try:
            handler = ScriptHelpXMLContentHandler.parse_nmap_script_help(process.stdout_file)
        except (ValueError, xml.sax.SAXParseException), e:
            log.debug("--script-help parse exception: %s" % str(e))
            return False

        # Check if any scripts were output; if not, Nmap is probably too old.
        if len(handler.script_filenames) == 0:
            return False

        if not handler.scripts_dir:
            log.debug("--script-help error: no scripts directory")
            return False
        if not handler.nselib_dir:
            log.debug("--script-help error: no nselib directory")
            return False

        log.debug("Script interface: scripts dir %s" % repr(handler.scripts_dir)) 
        log.debug("Script interface: nselib dir %s" % repr(handler.nselib_dir)) 

        # Make a dict of script metadata entries.
        entries = {}
        for entry in get_script_entries(handler.scripts_dir, handler.nselib_dir):
            entries[entry.filename] = entry

        self.liststore.clear()
        for filename in handler.script_filenames:
            basename = os.path.basename(filename)
            entry = entries.get(basename)
            if entry:
                script_id = self.strip_file_name(basename)
                self.liststore.append([script_id, False, entry])
            else:
                # ScriptMetadata found nothing for this script?
                self.file_liststore.append([filename, False])

        # Now figure out which scripts are selected.
        self.update_script_list_from_spec(self.ops["--script"])
        return True

    def update_script_list_from_spec(self, spec):
        """Callback method for user edit delay."""
        log.debug("Script interface: update_script_list_from_spec %s" % repr(spec))
        if spec:
            self.get_script_list(spec, self.update_script_list_cb)
        else:
            self.refresh_list_scripts([])

    def update_script_list_cb(self, status, process):
        log.debug("Script interface: update_script_list_cb %s" % repr(status))
        if status:
            self.handle_update_script_list_output(process)
        else:
            self.refresh_list_scripts([])

    def handle_update_script_list_output(self, process):
        process.stdout_file.seek(0)
        try:
            handler = ScriptHelpXMLContentHandler.parse_nmap_script_help(process.stdout_file)
        except (ValueError, xml.sax.SAXParseException), e:
            log.debug("--script-help parse exception: %s" % str(e))
            return False

        self.refresh_list_scripts(handler.script_filenames)

    def get_hmain_box(self):
        """Returns main Hbox to ProfileEditor."""
        return self.hmainbox

    def update(self):
        """Updates the interface when the command entry is changed."""
        #updates list of scripts
        script_list = []
        rules = self.ops["--script"]
        if (self.prev_script_spec != rules):
            self.renew_script_list_timer(rules)
        self.prev_script_spec = rules
        #updates arguments..
        raw_argument = self.ops["--script-args"]
        if raw_argument is not None:
            self.parse_script_args(raw_argument)
        self.arg_liststore.clear()
        for arg in self.current_arguments:
            arg_name, arg_desc = arg
            value = self.arg_values.get(arg_name)
            if not value:
                self.arg_liststore.append([arg_name, None, arg])
            else:
                self.arg_liststore.append([arg_name, value, arg])

    def renew_script_list_timer(self, spec):
        """Restart the timer to update the script list when the user edits the
        command. Because updating the script list is an expensive operation
        involving the creation of a subprocess, we don't do it for every typed
        character."""
        if self.script_list_timeout_id:
            gobject.source_remove(self.script_list_timeout_id)
        self.script_list_timeout_id = gobject.timeout_add(self.SCRIPT_LIST_DELAY, self.update_script_list_from_spec, spec)


    def parse_script_args(self,raw_argument):
        """When the command line is edited, this function is called to update
        the script arguments display according to the value of --script-args."""
        arg_dict = parse_script_args_dict(raw_argument)
        if arg_dict is None: # if there is parsing error args_dict holds none
            self.arg_values.clear()
        else:
            for key in arg_dict.keys():
                self.arg_values[key] = arg_dict[key]

    def update_argument_values(self,raw_argument):
        """When scripting tab starts up, argument values are updated."""
        if raw_argument is not None:
            self.parse_script_args(raw_argument)

    def set_help_texts(self):
        """Sets the help texts to be displayed."""
        self.list_scripts_help = _("List of scripts\n\nA list of all installed scripts. Activate or deactivate a script by clicking the box next to the script name.")
        self.description_help = _("Description\n\nThis box shows the categories a script belongs to. In addition, it gives a detailed description of the script which is present in script. A URL points to online NSEDoc documentation.")
        self.argument_help = _("Arguments\n\nA list of arguments that affect the selected script. Enter a value by clicking in the value field beside the argument name.")

    def make_please_wait_widget(self):
        vbox = gtk.VBox()
        label = gtk.Label(_("Please wait."))
        label.set_line_wrap(True)
        vbox.pack_start(label)
        return vbox

    def make_script_list_widget(self):
        """Creates and packs widgets associated with left hand side of Interface."""
        vbox = gtk.VBox()

        scrolled_window = HIGScrolledWindow()
        scrolled_window.set_policy(gtk.POLICY_ALWAYS, gtk.POLICY_ALWAYS)
        # Expand only vertically.
        scrolled_window.set_size_request(175, -1)
        previewentry = gtk.Entry()
        listview = gtk.TreeView(self.liststore)
        listview.set_headers_visible(False)
        listview.connect("enter-notify-event", self.update_help_ls_cb)
        selection = listview.get_selection()
        selection.connect("changed", self.selection_changed_cb)
        cell = gtk.CellRendererText()
        togglecell = gtk.CellRendererToggle()
        togglecell.set_property("activatable", True)
        togglecell.connect("toggled", self.toggled_cb, self.liststore)
        col = gtk.TreeViewColumn(_('Names'))
        col.set_sizing(gtk.TREE_VIEW_COLUMN_GROW_ONLY)
        col.set_resizable(True)
        togglecol = gtk.TreeViewColumn(None, togglecell)
        togglecol.add_attribute(togglecell, "active", 1)
        listview.append_column(togglecol)
        listview.append_column(col)
        col.pack_start(cell, True)
        col.add_attribute(cell, "text", 0)
        scrolled_window.add(listview)
        scrolled_window.show()
        vbox.pack_start(scrolled_window, True, True, 0)

        self.file_scrolled_window = HIGScrolledWindow()
        self.file_scrolled_window.set_policy(gtk.POLICY_ALWAYS, gtk.POLICY_ALWAYS)
        self.file_scrolled_window.set_size_request(175, -1)
        self.file_scrolled_window.hide()
        self.file_scrolled_window.set_no_show_all(True)

        self.file_listview = gtk.TreeView(self.file_liststore)
        self.file_listview.set_headers_visible(False)
        col = gtk.TreeViewColumn(None)
        self.file_listview.append_column(col)
        cell = gtk.CellRendererToggle()
        col.pack_start(cell, True)
        cell.set_property("activatable", True)
        col.add_attribute(cell, "active", 1)
        cell.connect("toggled", self.toggled_cb, self.file_liststore)

        col = gtk.TreeViewColumn(None)
        self.file_listview.append_column(col)
        cell = gtk.CellRendererText()
        col.pack_start(cell)
        col.add_attribute(cell, "text", 0)

        self.file_listview.show_all()
        self.file_scrolled_window.add(self.file_listview)
        vbox.pack_start(self.file_scrolled_window, False)

        hbox = HIGHBox(False, 2)
        self.remove_file_button = HIGButton(stock = gtk.STOCK_REMOVE)
        self.remove_file_button.connect("clicked", self.remove_file_button_clicked_cb)
        self.remove_file_button.set_sensitive(False)
        hbox.pack_end(self.remove_file_button)
        add_file_button = HIGButton(stock = gtk.STOCK_ADD)
        add_file_button.connect("clicked", self.add_file_button_clicked_cb)
        hbox.pack_end(add_file_button)

        vbox.pack_start(hbox, False, False, 0)

        return vbox

    def refresh_list_scripts(self, selected_scripts):
        """The list of selected scripts is refreshed in the list store."""
        for row in self.liststore:
            row[1] = False
        for row in self.file_liststore:
            row[1] = False
        for filename in selected_scripts:
            for row in self.liststore:
                if row[0] == self.strip_file_name(os.path.basename(filename)):
                    row[1] = True
                    break
            else:
                for row in self.file_liststore:
                    if row[0] == filename:
                        row[1] = True
                        break
                else:
                    self.file_liststore.append([filename, True])

    def strip_file_name(self,filename):
        """Removes a ".nse" extension from filename if present."""
        if(filename.endswith(".nse")):
            return filename[:-4]
        else:
            return filename

    def set_script_from_selection(self):
        scriptsname = []
        for entry in self.liststore:
            if entry[1]:
                scriptsname.append(self.strip_file_name(entry[0]))
        for entry in self.file_liststore:
            if entry[1]:
                scriptsname.append(entry[0])
        if len(scriptsname) == 0:
            self.ops["--script"] = None
        else:
            self.ops["--script"] = ",".join(scriptsname)
        self.update_command()

    def toggled_cb(self, cell, path, model):
        """Callback method, called when the check box in list of scripts is
        toggled."""
        model[path][1] = not model[path][1]
        self.set_script_from_selection()

    def make_description_widget(self):
        """Creates and packs widgets related to displaying the description
        box."""
        sw = HIGScrolledWindow()
        sw.set_policy(gtk.POLICY_AUTOMATIC, gtk.POLICY_ALWAYS)
        sw.set_shadow_type(gtk.SHADOW_OUT)
        sw.set_border_width(5)
        text_view = gtk.TextView()
        text_view.connect("enter-notify-event", self.update_help_desc_cb)
        self.text_buffer = text_view.get_buffer()
        self.text_buffer.create_tag("Usage", font = "Monospace")
        self.text_buffer.create_tag("Output", font = "Monospace")
        text_view.set_wrap_mode(gtk.WRAP_WORD)
        text_view.set_editable(False)
        text_view.set_justification(gtk.JUSTIFY_LEFT)
        sw.add(text_view)
        return sw

    def make_arguments_widget(self):
        """Creates and packs widgets related to arguments box."""
        vbox = gtk.VBox()
        vbox.pack_start(gtk.Label(_("Arguments")), False, False, 0)
        arg_window = HIGScrolledWindow()
        arg_window.set_policy(gtk.POLICY_AUTOMATIC, gtk.POLICY_ALWAYS)
        arg_window.set_shadow_type(gtk.SHADOW_OUT)

        arg_listview = gtk.TreeView(self.arg_liststore)
        arg_listview.connect("motion-notify-event", self.update_help_arg_cb)
        argument = gtk.CellRendererText()
        self.value = gtk.CellRendererText()
        self.value.connect("edited", self.value_edited_cb, self.arg_liststore)
        arg_col = gtk.TreeViewColumn("Arguments\t")
        val_col = gtk.TreeViewColumn("values")
        arg_listview.append_column(arg_col)
        arg_listview.append_column(val_col)
        arg_col.pack_start(argument, True)
        arg_col.add_attribute(argument, "text", 0)
        val_col.pack_start(self.value,True)
        val_col.add_attribute(self.value, "text", 1)

        arg_window.add(arg_listview)
        vbox.pack_start(arg_window, True, True, 0)

        return vbox

    def value_edited_cb(self,cell,path,new_text,model):
        """Called when the argument cell is edited."""
        self.arg_list = []
        model[path][1] = new_text
        argument_name = model[path][0]
        self.arg_values[argument_name] = new_text
        self.update_arg_values()

    def update_arg_values(self):
        """When the widget is updated with argument value, correspondingly
        update the command line."""
        for key in self.arg_values.keys():
            if len(self.arg_values[key]) == 0:
                del self.arg_values[key]
            else:
                self.arg_list.append(key + "=" + self.arg_values[key])
        if len(self.arg_list) == 0:
            self.ops["--script-args"] = None
            self.arg_values.clear()
        else:
            self.ops["--script-args"] = ",".join(self.arg_list)
        self.update_command()

    def selection_changed_cb(self,selection):
        """Called back when the list of scripts is selected."""
        model, selection = selection.get_selected_rows()
        for path in selection:
            check_value = model.get_value(model.get_iter(path),1)
            entry = model.get_value(model.get_iter(path),2)
            self.set_description(entry)
            self.populate_arg_list(entry)
            self.focussedentry = entry #Remember the currently pointing script entry

    def update_help_ls_cb(self,widget,extra): # list of scripts
        """Callback method to display the help for the list of scripts."""
        self.help_buf.set_text(self.list_scripts_help)

    def update_help_desc_cb(self,widget,extra):
        """Callback method for displaying description."""
        self.help_buf.set_text(self.description_help)

    def update_help_arg_cb(self, treeview, event):
        """Callback method for displaying argument help."""
        wx, wy = treeview.get_pointer()
        try:
            x, y = treeview.convert_widget_to_bin_window_coords(wx, wy)
        except AttributeError:
            # convert_widget_to_bin_window_coords was introduced in PyGTK 2.12.
            return
        path = treeview.get_path_at_pos(x, y)
        if not path or not self.focussedentry:
            self.help_buf.set_text("")
            return
        path = path[0]
        model, selected = treeview.get_selection().get_selected()
        arg_name, arg_desc = model.get_value(model.get_iter(path), 2)
        if arg_desc is not None:
            self.help_buf.set_text("")
            self.help_buf.insert(self.help_buf.get_end_iter(), text = "%s\n" % arg_name)
            text_buffer_insert_nsedoc(self.help_buf, arg_desc)
        else:
            self.help_buf.set_text("")

    def add_file_button_clicked_cb(self, button):
        if self.script_file_chooser is None:
            self.script_file_chooser = zenmapGUI.FileChoosers.ScriptFileChooserDialog(title = _("Select script files"))
        response = self.script_file_chooser.run()
        filenames = self.script_file_chooser.get_filenames()
        self.script_file_chooser.hide()
        if response != gtk.RESPONSE_OK:
            return
        for filename in filenames:
            self.file_liststore.append([filename, True])
        if len(self.file_liststore) > 0:
            self.file_scrolled_window.show()
            self.remove_file_button.set_sensitive(True)
        self.set_script_from_selection()

    def remove_file_button_clicked_cb(self, button):
        selection = self.file_listview.get_selection()
        model, selection = selection.get_selected_rows()
        for path in selection:
            self.file_liststore.remove(model.get_iter(path))
        if len(self.file_liststore) == 0:
            self.file_scrolled_window.hide()
            self.remove_file_button.set_sensitive(False)
        self.set_script_from_selection()

    def set_description(self,entry):
        """Sets the content that is to be displayed in the description box."""
        self.text_buffer.set_text(u"")

        self.text_buffer.insert(self.text_buffer.get_end_iter(), """\
Categories: %(cats)s
""" % {"cats": ", ".join(entry.categories)})
        text_buffer_insert_nsedoc(self.text_buffer, entry.description)
        if entry.usage:
            self.text_buffer.insert(self.text_buffer.get_end_iter(), "\nUsage\n")
            self.text_buffer.insert_with_tags_by_name(self.text_buffer.get_end_iter(), entry.usage, "Usage")
        if entry.output:
            self.text_buffer.insert(self.text_buffer.get_end_iter(), "\nOutput\n")
            self.text_buffer.insert_with_tags_by_name(self.text_buffer.get_end_iter(), entry.output, "Output")
        if entry.url:
            self.text_buffer.insert(self.text_buffer.get_end_iter(), "\n" + entry.url)

    def populate_arg_list(self,entry):
        """Called when a particular script is hovered over to display its
        arguments and values (if any)."""
        self.arg_liststore.clear()
        self.current_arguments = []
        self.value.set_property('editable',True)
        for arg in entry.arguments:
            arg_name, arg_desc = arg
            self.current_arguments.append(arg)
            value = self.arg_values.get(arg_name)
            if not value:
                self.arg_liststore.append([arg_name, None, arg])
            else:
                self.arg_liststore.append([arg_name, value, arg])