pbx.c

Go to the documentation of this file.

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2008, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Core PBX routines.
 *
 * \author Mark Spencer <markster@digium.com>
 */

/*** MODULEINFO
   <support_level>core</support_level>
 ***/

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 374778 $")

#include "asterisk/_private.h"
#include "asterisk/paths.h"   /* use ast_config_AST_SYSTEM_NAME */
#include <ctype.h>
#include <time.h>
#include <sys/time.h>
#if defined(HAVE_SYSINFO)
#include <sys/sysinfo.h>
#endif
#if defined(SOLARIS)
#include <sys/loadavg.h>
#endif

#include "asterisk/lock.h"
#include "asterisk/cli.h"
#include "asterisk/pbx.h"
#include "asterisk/channel.h"
#include "asterisk/file.h"
#include "asterisk/callerid.h"
#include "asterisk/cdr.h"
#include "asterisk/cel.h"
#include "asterisk/config.h"
#include "asterisk/term.h"
#include "asterisk/time.h"
#include "asterisk/manager.h"
#include "asterisk/ast_expr.h"
#include "asterisk/linkedlists.h"
#define  SAY_STUBS   /* generate declarations and stubs for say methods */
#include "asterisk/say.h"
#include "asterisk/utils.h"
#include "asterisk/causes.h"
#include "asterisk/musiconhold.h"
#include "asterisk/app.h"
#include "asterisk/devicestate.h"
#include "asterisk/presencestate.h"
#include "asterisk/event.h"
#include "asterisk/hashtab.h"
#include "asterisk/module.h"
#include "asterisk/indications.h"
#include "asterisk/taskprocessor.h"
#include "asterisk/xmldoc.h"
#include "asterisk/astobj2.h"

/*!
 * \note I M P O R T A N T :
 *
 *    The speed of extension handling will likely be among the most important
 * aspects of this PBX.  The switching scheme as it exists right now isn't
 * terribly bad (it's O(N+M), where N is the # of extensions and M is the avg #
 * of priorities, but a constant search time here would be great ;-)
 *
 * A new algorithm to do searching based on a 'compiled' pattern tree is introduced
 * here, and shows a fairly flat (constant) search time, even for over
 * 10000 patterns.
 *
 * Also, using a hash table for context/priority name lookup can help prevent
 * the find_extension routines from absorbing exponential cpu cycles as the number
 * of contexts/priorities grow. I've previously tested find_extension with red-black trees,
 * which have O(log2(n)) speed. Right now, I'm using hash tables, which do
 * searches (ideally) in O(1) time. While these techniques do not yield much
 * speed in small dialplans, they are worth the trouble in large dialplans.
 *
 */

/*** DOCUMENTATION
   <application name="Answer" language="en_US">
      <synopsis>
         Answer a channel if ringing.
      </synopsis>
      <syntax>
         <parameter name="delay">
            <para>Asterisk will wait this number of milliseconds before returning to
            the dialplan after answering the call.</para>
         </parameter>
         <parameter name="nocdr">
            <para>Asterisk will send an answer signal to the calling phone, but will not
            set the disposition or answer time in the CDR for this call.</para>
         </parameter>
      </syntax>
      <description>
         <para>If the call has not been answered, this application will
         answer it. Otherwise, it has no effect on the call.</para>
      </description>
      <see-also>
         <ref type="application">Hangup</ref>
      </see-also>
   </application>
   <application name="BackGround" language="en_US">
      <synopsis>
         Play an audio file while waiting for digits of an extension to go to.
      </synopsis>
      <syntax>
         <parameter name="filenames" required="true" argsep="&amp;">
            <argument name="filename1" required="true" />
            <argument name="filename2" multiple="true" />
         </parameter>
         <parameter name="options">
            <optionlist>
               <option name="s">
                  <para>Causes the playback of the message to be skipped
                  if the channel is not in the <literal>up</literal> state (i.e. it
                  hasn't been answered yet). If this happens, the
                  application will return immediately.</para>
               </option>
               <option name="n">
                  <para>Don't answer the channel before playing the files.</para>
               </option>
               <option name="m">
                  <para>Only break if a digit hit matches a one digit
                  extension in the destination context.</para>
               </option>
            </optionlist>
         </parameter>
         <parameter name="langoverride">
            <para>Explicitly specifies which language to attempt to use for the requested sound files.</para>
         </parameter>
         <parameter name="context">
            <para>This is the dialplan context that this application will use when exiting
            to a dialed extension.</para>
         </parameter>
      </syntax>
      <description>
         <para>This application will play the given list of files <emphasis>(do not put extension)</emphasis>
         while waiting for an extension to be dialed by the calling channel. To continue waiting
         for digits after this application has finished playing files, the <literal>WaitExten</literal>
         application should be used.</para>
         <para>If one of the requested sound files does not exist, call processing will be terminated.</para>
         <para>This application sets the following channel variable upon completion:</para>
         <variablelist>
            <variable name="BACKGROUNDSTATUS">
               <para>The status of the background attempt as a text string.</para>
               <value name="SUCCESS" />
               <value name="FAILED" />
            </variable>
         </variablelist>
      </description>
      <see-also>
         <ref type="application">ControlPlayback</ref>
         <ref type="application">WaitExten</ref>
         <ref type="application">BackgroundDetect</ref>
         <ref type="function">TIMEOUT</ref>
      </see-also>
   </application>
   <application name="Busy" language="en_US">
      <synopsis>
         Indicate the Busy condition.
      </synopsis>
      <syntax>
         <parameter name="timeout">
            <para>If specified, the calling channel will be hung up after the specified number of seconds.
            Otherwise, this application will wait until the calling channel hangs up.</para>
         </parameter>
      </syntax>
      <description>
         <para>This application will indicate the busy condition to the calling channel.</para>
      </description>
      <see-also>
         <ref type="application">Congestion</ref>
         <ref type="application">Progress</ref>
         <ref type="application">Playtones</ref>
         <ref type="application">Hangup</ref>
      </see-also>
   </application>
   <application name="Congestion" language="en_US">
      <synopsis>
         Indicate the Congestion condition.
      </synopsis>
      <syntax>
         <parameter name="timeout">
            <para>If specified, the calling channel will be hung up after the specified number of seconds.
            Otherwise, this application will wait until the calling channel hangs up.</para>
         </parameter>
      </syntax>
      <description>
         <para>This application will indicate the congestion condition to the calling channel.</para>
      </description>
      <see-also>
         <ref type="application">Busy</ref>
         <ref type="application">Progress</ref>
         <ref type="application">Playtones</ref>
         <ref type="application">Hangup</ref>
      </see-also>
   </application>
   <application name="ExecIfTime" language="en_US">
      <synopsis>
         Conditional application execution based on the current time.
      </synopsis>
      <syntax argsep="?">
         <parameter name="day_condition" required="true">
            <argument name="times" required="true" />
            <argument name="weekdays" required="true" />
            <argument name="mdays" required="true" />
            <argument name="months" required="true" />
            <argument name="timezone" required="false" />
         </parameter>
         <parameter name="appname" required="true" hasparams="optional">
            <argument name="appargs" required="true" />
         </parameter>
      </syntax>
      <description>
         <para>This application will execute the specified dialplan application, with optional
         arguments, if the current time matches the given time specification.</para>
      </description>
      <see-also>
         <ref type="application">Exec</ref>
         <ref type="application">ExecIf</ref>
         <ref type="application">TryExec</ref>
         <ref type="application">GotoIfTime</ref>
      </see-also>
   </application>
   <application name="Goto" language="en_US">
      <synopsis>
         Jump to a particular priority, extension, or context.
      </synopsis>
      <syntax>
         <parameter name="context" />
         <parameter name="extensions" />
         <parameter name="priority" required="true" />
      </syntax>
      <description>
         <para>This application will set the current context, extension, and priority in the channel structure.
         After it completes, the pbx engine will continue dialplan execution at the specified location.
         If no specific <replaceable>extension</replaceable>, or <replaceable>extension</replaceable> and
         <replaceable>context</replaceable>, are specified, then this application will
         just set the specified <replaceable>priority</replaceable> of the current extension.</para>
         <para>At least a <replaceable>priority</replaceable> is required as an argument, or the goto will
         return a <literal>-1</literal>,  and the channel and call will be terminated.</para>
         <para>If the location that is put into the channel information is bogus, and asterisk cannot
         find that location in the dialplan, then the execution engine will try to find and execute the code in
         the <literal>i</literal> (invalid) extension in the current context. If that does not exist, it will try to execute the
         <literal>h</literal> extension. If neither the <literal>h</literal> nor <literal>i</literal> extensions
         have been defined, the channel is hung up, and the execution of instructions on the channel is terminated.
         What this means is that, for example, you specify a context that does not exist, then
         it will not be possible to find the <literal>h</literal> or <literal>i</literal> extensions,
         and the call will terminate!</para>
      </description>
      <see-also>
         <ref type="application">GotoIf</ref>
         <ref type="application">GotoIfTime</ref>
         <ref type="application">Gosub</ref>
         <ref type="application">Macro</ref>
      </see-also>
   </application>
   <application name="GotoIf" language="en_US">
      <synopsis>
         Conditional goto.
      </synopsis>
      <syntax argsep="?">
         <parameter name="condition" required="true" />
         <parameter name="destination" required="true" argsep=":">
            <argument name="labeliftrue">
               <para>Continue at <replaceable>labeliftrue</replaceable> if the condition is true.
               Takes the form similar to Goto() of [[context,]extension,]priority.</para>
            </argument>
            <argument name="labeliffalse">
               <para>Continue at <replaceable>labeliffalse</replaceable> if the condition is false.
               Takes the form similar to Goto() of [[context,]extension,]priority.</para>
            </argument>
         </parameter>
      </syntax>
      <description>
         <para>This application will set the current context, extension, and priority in the channel structure
         based on the evaluation of the given condition. After this application completes, the
         pbx engine will continue dialplan execution at the specified location in the dialplan.
         The labels are specified with the same syntax as used within the Goto application.
         If the label chosen by the condition is omitted, no jump is performed, and the execution passes to the
         next instruction. If the target location is bogus, and does not exist, the execution engine will try
         to find and execute the code in the <literal>i</literal> (invalid) extension in the current context.
         If that does not exist, it will try to execute the <literal>h</literal> extension.
         If neither the <literal>h</literal> nor <literal>i</literal> extensions have been defined,
         the channel is hung up, and the execution of instructions on the channel is terminated.
         Remember that this command can set the current context, and if the context specified
         does not exist, then it will not be able to find any 'h' or 'i' extensions there, and
         the channel and call will both be terminated!.</para>
      </description>
      <see-also>
         <ref type="application">Goto</ref>
         <ref type="application">GotoIfTime</ref>
         <ref type="application">GosubIf</ref>
         <ref type="application">MacroIf</ref>
      </see-also>
   </application>
   <application name="GotoIfTime" language="en_US">
      <synopsis>
         Conditional Goto based on the current time.
      </synopsis>
      <syntax argsep="?">
         <parameter name="condition" required="true">
            <argument name="times" required="true" />
            <argument name="weekdays" required="true" />
            <argument name="mdays" required="true" />
            <argument name="months" required="true" />
            <argument name="timezone" required="false" />
         </parameter>
         <parameter name="destination" required="true" argsep=":">
            <argument name="labeliftrue">
               <para>Continue at <replaceable>labeliftrue</replaceable> if the condition is true.
               Takes the form similar to Goto() of [[context,]extension,]priority.</para>
            </argument>
            <argument name="labeliffalse">
               <para>Continue at <replaceable>labeliffalse</replaceable> if the condition is false.
               Takes the form similar to Goto() of [[context,]extension,]priority.</para>
            </argument>
         </parameter>
      </syntax>
      <description>
         <para>This application will set the context, extension, and priority in the channel structure
         based on the evaluation of the given time specification. After this application completes,
         the pbx engine will continue dialplan execution at the specified location in the dialplan.
         If the current time is within the given time specification, the channel will continue at
         <replaceable>labeliftrue</replaceable>. Otherwise the channel will continue at <replaceable>labeliffalse</replaceable>.
         If the label chosen by the condition is omitted, no jump is performed, and execution passes to the next
         instruction. If the target jump location is bogus, the same actions would be taken as for <literal>Goto</literal>.
         Further information on the time specification can be found in examples
         illustrating how to do time-based context includes in the dialplan.</para>
      </description>
      <see-also>
         <ref type="application">GotoIf</ref>
         <ref type="application">Goto</ref>
         <ref type="function">IFTIME</ref>
         <ref type="function">TESTTIME</ref>
      </see-also>
   </application>
   <application name="ImportVar" language="en_US">
      <synopsis>
         Import a variable from a channel into a new variable.
      </synopsis>
      <syntax argsep="=">
         <parameter name="newvar" required="true" />
         <parameter name="vardata" required="true">
            <argument name="channelname" required="true" />
            <argument name="variable" required="true" />
         </parameter>
      </syntax>
      <description>
         <para>This application imports a <replaceable>variable</replaceable> from the specified
         <replaceable>channel</replaceable> (as opposed to the current one) and stores it as a variable
         (<replaceable>newvar</replaceable>) in the current channel (the channel that is calling this
         application). Variables created by this application have the same inheritance properties as those
         created with the <literal>Set</literal> application.</para>
      </description>
      <see-also>
         <ref type="application">Set</ref>
      </see-also>
   </application>
   <application name="Hangup" language="en_US">
      <synopsis>
         Hang up the calling channel.
      </synopsis>
      <syntax>
         <parameter name="causecode">
            <para>If a <replaceable>causecode</replaceable> is given the channel's
            hangup cause will be set to the given value.</para>
         </parameter>
      </syntax>
      <description>
         <para>This application will hang up the calling channel.</para>
      </description>
      <see-also>
         <ref type="application">Answer</ref>
         <ref type="application">Busy</ref>
         <ref type="application">Congestion</ref>
      </see-also>
   </application>
   <application name="Incomplete" language="en_US">
      <synopsis>
         Returns AST_PBX_INCOMPLETE value.
      </synopsis>
      <syntax>
         <parameter name="n">
            <para>If specified, then Incomplete will not attempt to answer the channel first.</para>
            <note><para>Most channel types need to be in Answer state in order to receive DTMF.</para></note>
         </parameter>
      </syntax>
      <description>
         <para>Signals the PBX routines that the previous matched extension is incomplete
         and that further input should be allowed before matching can be considered
         to be complete.  Can be used within a pattern match when certain criteria warrants
         a longer match.</para>
      </description>
   </application>
   <application name="NoOp" language="en_US">
      <synopsis>
         Do Nothing (No Operation).
      </synopsis>
      <syntax>
         <parameter name="text">
            <para>Any text provided can be viewed at the Asterisk CLI.</para>
         </parameter>
      </syntax>
      <description>
         <para>This application does nothing. However, it is useful for debugging purposes.</para>
         <para>This method can be used to see the evaluations of variables or functions without having any effect.</para>
      </description>
      <see-also>
         <ref type="application">Verbose</ref>
         <ref type="application">Log</ref>
      </see-also>
   </application>
   <application name="Proceeding" language="en_US">
      <synopsis>
         Indicate proceeding.
      </synopsis>
      <syntax />
      <description>
         <para>This application will request that a proceeding message be provided to the calling channel.</para>
      </description>
   </application>
   <application name="Progress" language="en_US">
      <synopsis>
         Indicate progress.
      </synopsis>
      <syntax />
      <description>
         <para>This application will request that in-band progress information be provided to the calling channel.</para>
      </description>
      <see-also>
         <ref type="application">Busy</ref>
         <ref type="application">Congestion</ref>
         <ref type="application">Ringing</ref>
         <ref type="application">Playtones</ref>
      </see-also>
   </application>
   <application name="RaiseException" language="en_US">
      <synopsis>
         Handle an exceptional condition.
      </synopsis>
      <syntax>
         <parameter name="reason" required="true" />
      </syntax>
      <description>
         <para>This application will jump to the <literal>e</literal> extension in the current context, setting the
         dialplan function EXCEPTION(). If the <literal>e</literal> extension does not exist, the call will hangup.</para>
      </description>
      <see-also>
         <ref type="function">Exception</ref>
      </see-also>
   </application>
   <application name="ResetCDR" language="en_US">
      <synopsis>
         Resets the Call Data Record.
      </synopsis>
      <syntax>
         <parameter name="options">
            <optionlist>
               <option name="w">
                  <para>Store the current CDR record before resetting it.</para>
               </option>
               <option name="a">
                  <para>Store any stacked records.</para>
               </option>
               <option name="v">
                  <para>Save CDR variables.</para>
               </option>
               <option name="e">
                  <para>Enable CDR only (negate effects of NoCDR).</para>
               </option>
            </optionlist>
         </parameter>
      </syntax>
      <description>
         <para>This application causes the Call Data Record to be reset.</para>
      </description>
      <see-also>
         <ref type="application">ForkCDR</ref>
         <ref type="application">NoCDR</ref>
      </see-also>
   </application>
   <application name="Ringing" language="en_US">
      <synopsis>
         Indicate ringing tone.
      </synopsis>
      <syntax />
      <description>
         <para>This application will request that the channel indicate a ringing tone to the user.</para>
      </description>
      <see-also>
         <ref type="application">Busy</ref>
         <ref type="application">Congestion</ref>
         <ref type="application">Progress</ref>
         <ref type="application">Playtones</ref>
      </see-also>
   </application>
   <application name="SayAlpha" language="en_US">
      <synopsis>
         Say Alpha.
      </synopsis>
      <syntax>
         <parameter name="string" required="true" />
      </syntax>
      <description>
         <para>This application will play the sounds that correspond to the letters of the
         given <replaceable>string</replaceable>.</para>
      </description>
      <see-also>
         <ref type="application">SayDigits</ref>
         <ref type="application">SayNumber</ref>
         <ref type="application">SayPhonetic</ref>
         <ref type="function">CHANNEL</ref>
      </see-also>
   </application>
   <application name="SayDigits" language="en_US">
      <synopsis>
         Say Digits.
      </synopsis>
      <syntax>
         <parameter name="digits" required="true" />
      </syntax>
      <description>
         <para>This application will play the sounds that correspond to the digits of
         the given number. This will use the language that is currently set for the channel.</para>
      </description>
      <see-also>
         <ref type="application">SayAlpha</ref>
         <ref type="application">SayNumber</ref>
         <ref type="application">SayPhonetic</ref>
         <ref type="function">CHANNEL</ref>
      </see-also>
   </application>
   <application name="SayNumber" language="en_US">
      <synopsis>
         Say Number.
      </synopsis>
      <syntax>
         <parameter name="digits" required="true" />
         <parameter name="gender" />
      </syntax>
      <description>
         <para>This application will play the sounds that correspond to the given <replaceable>digits</replaceable>.
         Optionally, a <replaceable>gender</replaceable> may be specified. This will use the language that is currently
         set for the channel. See the CHANNEL() function for more information on setting the language for the channel.</para>
      </description>
      <see-also>
         <ref type="application">SayAlpha</ref>
         <ref type="application">SayDigits</ref>
         <ref type="application">SayPhonetic</ref>
         <ref type="function">CHANNEL</ref>
      </see-also>
   </application>
   <application name="SayPhonetic" language="en_US">
      <synopsis>
         Say Phonetic.
      </synopsis>
      <syntax>
         <parameter name="string" required="true" />
      </syntax>
      <description>
         <para>This application will play the sounds from the phonetic alphabet that correspond to the
         letters in the given <replaceable>string</replaceable>.</para>
      </description>
      <see-also>
         <ref type="application">SayAlpha</ref>
         <ref type="application">SayDigits</ref>
         <ref type="application">SayNumber</ref>
      </see-also>
   </application>
   <application name="Set" language="en_US">
      <synopsis>
         Set channel variable or function value.
      </synopsis>
      <syntax argsep="=">
         <parameter name="name" required="true" />
         <parameter name="value" required="true" />
      </syntax>
      <description>
         <para>This function can be used to set the value of channel variables or dialplan functions.
         When setting variables, if the variable name is prefixed with <literal>_</literal>,
         the variable will be inherited into channels created from the current channel.
         If the variable name is prefixed with <literal>__</literal>, the variable will be
         inherited into channels created from the current channel and all children channels.</para>
         <note><para>If (and only if), in <filename>/etc/asterisk/asterisk.conf</filename>, you have
         a <literal>[compat]</literal> category, and you have <literal>app_set = 1.4</literal> under that, then
         the behavior of this app changes, and strips surrounding quotes from the right hand side as
         it did previously in 1.4.
         The advantages of not stripping out quoting, and not caring about the separator characters (comma and vertical bar)
         were sufficient to make these changes in 1.6. Confusion about how many backslashes would be needed to properly
         protect separators and quotes in various database access strings has been greatly
         reduced by these changes.</para></note>
      </description>
      <see-also>
         <ref type="application">MSet</ref>
         <ref type="function">GLOBAL</ref>
         <ref type="function">SET</ref>
         <ref type="function">ENV</ref>
      </see-also>
   </application>
   <application name="MSet" language="en_US">
      <synopsis>
         Set channel variable(s) or function value(s).
      </synopsis>
      <syntax>
         <parameter name="set1" required="true" argsep="=">
            <argument name="name1" required="true" />
            <argument name="value1" required="true" />
         </parameter>
         <parameter name="set2" multiple="true" argsep="=">
            <argument name="name2" required="true" />
            <argument name="value2" required="true" />
         </parameter>
      </syntax>
      <description>
         <para>This function can be used to set the value of channel variables or dialplan functions.
         When setting variables, if the variable name is prefixed with <literal>_</literal>,
         the variable will be inherited into channels created from the current channel
         If the variable name is prefixed with <literal>__</literal>, the variable will be
         inherited into channels created from the current channel and all children channels.
         MSet behaves in a similar fashion to the way Set worked in 1.2/1.4 and is thus
         prone to doing things that you may not expect. For example, it strips surrounding
         double-quotes from the right-hand side (value). If you need to put a separator
         character (comma or vert-bar), you will need to escape them by inserting a backslash
         before them. Avoid its use if possible.</para>
      </description>
      <see-also>
         <ref type="application">Set</ref>
      </see-also>
   </application>
   <application name="SetAMAFlags" language="en_US">
      <synopsis>
         Set the AMA Flags.
      </synopsis>
      <syntax>
         <parameter name="flag" />
      </syntax>
      <description>
         <para>This application will set the channel's AMA Flags for billing purposes.</para>
      </description>
      <see-also>
         <ref type="function">CDR</ref>
      </see-also>
   </application>
   <application name="Wait" language="en_US">
      <synopsis>
         Waits for some time.
      </synopsis>
      <syntax>
         <parameter name="seconds" required="true">
            <para>Can be passed with fractions of a second. For example, <literal>1.5</literal> will ask the
            application to wait for 1.5 seconds.</para>
         </parameter>
      </syntax>
      <description>
         <para>This application waits for a specified number of <replaceable>seconds</replaceable>.</para>
      </description>
   </application>
   <application name="WaitExten" language="en_US">
      <synopsis>
         Waits for an extension to be entered.
      </synopsis>
      <syntax>
         <parameter name="seconds">
            <para>Can be passed with fractions of a second. For example, <literal>1.5</literal> will ask the
            application to wait for 1.5 seconds.</para>
         </parameter>
         <parameter name="options">
            <optionlist>
               <option name="m">
                  <para>Provide music on hold to the caller while waiting for an extension.</para>
                  <argument name="x">
                     <para>Specify the class for music on hold. <emphasis>CHANNEL(musicclass) will
                     be used instead if set</emphasis></para>
                  </argument>
               </option>
            </optionlist>
         </parameter>
      </syntax>
      <description>
         <para>This application waits for the user to enter a new extension for a specified number
         of <replaceable>seconds</replaceable>.</para>
         <xi:include xpointer="xpointer(/docs/application[@name='Macro']/description/warning[2])" />
      </description>
      <see-also>
         <ref type="application">Background</ref>
         <ref type="function">TIMEOUT</ref>
      </see-also>
   </application>
   <function name="EXCEPTION" language="en_US">
      <synopsis>
         Retrieve the details of the current dialplan exception.
      </synopsis>
      <syntax>
         <parameter name="field" required="true">
            <para>The following fields are available for retrieval:</para>
            <enumlist>
               <enum name="reason">
                  <para>INVALID, ERROR, RESPONSETIMEOUT, ABSOLUTETIMEOUT, or custom
                  value set by the RaiseException() application</para>
               </enum>
               <enum name="context">
                  <para>The context executing when the exception occurred.</para>
               </enum>
               <enum name="exten">
                  <para>The extension executing when the exception occurred.</para>
               </enum>
               <enum name="priority">
                  <para>The numeric priority executing when the exception occurred.</para>
               </enum>
            </enumlist>
         </parameter>
      </syntax>
      <description>
         <para>Retrieve the details (specified <replaceable>field</replaceable>) of the current dialplan exception.</para>
      </description>
      <see-also>
         <ref type="application">RaiseException</ref>
      </see-also>
   </function>
   <function name="TESTTIME" language="en_US">
      <synopsis>
         Sets a time to be used with the channel to test logical conditions.
      </synopsis>
      <syntax>
         <parameter name="date" required="true" argsep=" ">
            <para>Date in ISO 8601 format</para>
         </parameter>
         <parameter name="time" required="true" argsep=" ">
            <para>Time in HH:MM:SS format (24-hour time)</para>
         </parameter>
         <parameter name="zone" required="false">
            <para>Timezone name</para>
         </parameter>
      </syntax>
      <description>
         <para>To test dialplan timing conditions at times other than the current time, use
         this function to set an alternate date and time.  For example, you may wish to evaluate
         whether a location will correctly identify to callers that the area is closed on Christmas
         Day, when Christmas would otherwise fall on a day when the office is normally open.</para>
      </description>
      <see-also>
         <ref type="application">GotoIfTime</ref>
      </see-also>
   </function>
   <manager name="ShowDialPlan" language="en_US">
      <synopsis>
         Show dialplan contexts and extensions
      </synopsis>
      <syntax>
         <xi:include xpointer="xpointer(/docs/manager[@name='Login']/syntax/parameter[@name='ActionID'])" />
         <parameter name="Extension">
            <para>Show a specific extension.</para>
         </parameter>
         <parameter name="Context">
            <para>Show a specific context.</para>
         </parameter>
      </syntax>
      <description>
         <para>Show dialplan contexts and extensions. Be aware that showing the full dialplan
         may take a lot of capacity.</para>
      </description>
   </manager>
 ***/

#ifdef LOW_MEMORY
#define EXT_DATA_SIZE 256
#else
#define EXT_DATA_SIZE 8192
#endif

#define SWITCH_DATA_LENGTH 256

#define VAR_BUF_SIZE 4096

#define  VAR_NORMAL     1
#define  VAR_SOFTTRAN   2
#define  VAR_HARDTRAN   3

#define BACKGROUND_SKIP    (1 << 0)
#define BACKGROUND_NOANSWER   (1 << 1)
#define BACKGROUND_MATCHEXTEN (1 << 2)
#define BACKGROUND_PLAYBACK   (1 << 3)

AST_APP_OPTIONS(background_opts, {
   AST_APP_OPTION('s', BACKGROUND_SKIP),
   AST_APP_OPTION('n', BACKGROUND_NOANSWER),
   AST_APP_OPTION('m', BACKGROUND_MATCHEXTEN),
   AST_APP_OPTION('p', BACKGROUND_PLAYBACK),
});

#define WAITEXTEN_MOH      (1 << 0)
#define WAITEXTEN_DIALTONE (1 << 1)

AST_APP_OPTIONS(waitexten_opts, {
   AST_APP_OPTION_ARG('m', WAITEXTEN_MOH, 0),
   AST_APP_OPTION_ARG('d', WAITEXTEN_DIALTONE, 0),
});

struct ast_context;
struct ast_app;

static struct ast_taskprocessor *extension_state_tps;

AST_THREADSTORAGE(switch_data);
AST_THREADSTORAGE(extensionstate_buf);

/*!
   \brief ast_exten: An extension
   The dialplan is saved as a linked list with each context
   having it's own linked list of extensions - one item per
   priority.
*/
struct ast_exten {
   char *exten;         /*!< Extension name */
   int matchcid;        /*!< Match caller id ? */
   const char *cidmatch;      /*!< Caller id to match for this extension */
   int priority;        /*!< Priority */
   const char *label;      /*!< Label */
   struct ast_context *parent;   /*!< The context this extension belongs to  */
   const char *app;     /*!< Application to execute */
   struct ast_app *cached_app;     /*!< Cached location of application */
   void *data;       /*!< Data to use (arguments) */
   void (*datad)(void *);     /*!< Data destructor */
   struct ast_exten *peer;    /*!< Next higher priority with our extension */
   struct ast_hashtab *peer_table;    /*!< Priorities list in hashtab form -- only on the head of the peer list */
   struct ast_hashtab *peer_label_table; /*!< labeled priorities in the peers -- only on the head of the peer list */
   const char *registrar;     /*!< Registrar */
   struct ast_exten *next;    /*!< Extension with a greater ID */
   char stuff[0];
};

/*! \brief ast_include: include= support in extensions.conf */
struct ast_include {
   const char *name;
   const char *rname;         /*!< Context to include */
   const char *registrar;        /*!< Registrar */
   int hastime;            /*!< If time construct exists */
   struct ast_timing timing;               /*!< time construct */
   struct ast_include *next;     /*!< Link them together */
   char stuff[0];
};

/*! \brief ast_sw: Switch statement in extensions.conf */
struct ast_sw {
   char *name;
   const char *registrar;        /*!< Registrar */
   char *data;          /*!< Data load */
   int eval;
   AST_LIST_ENTRY(ast_sw) list;
   char stuff[0];
};

/*! \brief ast_ignorepat: Ignore patterns in dial plan */
struct ast_ignorepat {
   const char *registrar;
   struct ast_ignorepat *next;
   const char pattern[0];
};

/*! \brief match_char: forms a syntax tree for quick matching of extension patterns */
struct match_char
{
   int is_pattern; /* the pattern started with '_' */
   int deleted;    /* if this is set, then... don't return it */
   int specificity; /* simply the strlen of x, or 10 for X, 9 for Z, and 8 for N; and '.' and '!' will add 11 ? */
   struct match_char *alt_char;
   struct match_char *next_char;
   struct ast_exten *exten; /* attached to last char of a pattern for exten */
   char x[1];       /* the pattern itself-- matches a single char */
};

struct scoreboard  /* make sure all fields are 0 before calling new_find_extension */
{
   int total_specificity;
   int total_length;
   char last_char;   /* set to ! or . if they are the end of the pattern */
   int canmatch;     /* if the string to match was just too short */
   struct match_char *node;
   struct ast_exten *canmatch_exten;
   struct ast_exten *exten;
};

/*! \brief ast_context: An extension context */
struct ast_context {
   ast_rwlock_t lock;         /*!< A lock to prevent multiple threads from clobbering the context */
   struct ast_exten *root;       /*!< The root of the list of extensions */
   struct ast_hashtab *root_table;            /*!< For exact matches on the extensions in the pattern tree, and for traversals of the pattern_tree  */
   struct match_char *pattern_tree;        /*!< A tree to speed up extension pattern matching */
   struct ast_context *next;     /*!< Link them together */
   struct ast_include *includes;    /*!< Include other contexts */
   struct ast_ignorepat *ignorepats;   /*!< Patterns for which to continue playing dialtone */
   char *registrar;        /*!< Registrar -- make sure you malloc this, as the registrar may have to survive module unloads */
   int refcount;                   /*!< each module that would have created this context should inc/dec this as appropriate */
   AST_LIST_HEAD_NOLOCK(, ast_sw) alts;   /*!< Alternative switches */
   ast_mutex_t macrolock;        /*!< A lock to implement "exclusive" macros - held whilst a call is executing in the macro */
   char name[0];           /*!< Name of the context */
};

/*! \brief ast_app: A registered application */
struct ast_app {
   int (*execute)(struct ast_channel *chan, const char *data);
   AST_DECLARE_STRING_FIELDS(
      AST_STRING_FIELD(synopsis);     /*!< Synopsis text for 'show applications' */
      AST_STRING_FIELD(description);  /*!< Description (help text) for 'show application &lt;name&gt;' */
      AST_STRING_FIELD(syntax);       /*!< Syntax text for 'core show applications' */
      AST_STRING_FIELD(arguments);    /*!< Arguments description */
      AST_STRING_FIELD(seealso);      /*!< See also */
   );
#ifdef AST_XML_DOCS
   enum ast_doc_src docsrc;      /*!< Where the documentation come from. */
#endif
   AST_RWLIST_ENTRY(ast_app) list;     /*!< Next app in list */
   struct ast_module *module;    /*!< Module this app belongs to */
   char name[0];           /*!< Name of the application */
};

/*! \brief ast_state_cb: An extension state notify register item */
struct ast_state_cb {
   /*! Watcher ID returned when registered. */
   int id;
   /*! Arbitrary data passed for callbacks. */
   void *data;
   /*! Flag if this callback is an extended callback containing detailed device status */
   int extended;
   /*! Callback when state changes. */
   ast_state_cb_type change_cb;
   /*! Callback when destroyed so any resources given by the registerer can be freed. */
   ast_state_cb_destroy_type destroy_cb;
   /*! \note Only used by ast_merge_contexts_and_delete */
   AST_LIST_ENTRY(ast_state_cb) entry;
};

/*!
 * \brief Structure for dial plan hints
 *
 * \note Hints are pointers from an extension in the dialplan to
 * one or more devices (tech/name)
 *
 * See \ref AstExtState
 */
struct ast_hint {
   /*!
    * \brief Hint extension
    *
    * \note
    * Will never be NULL while the hint is in the hints container.
    */
   struct ast_exten *exten;
   struct ao2_container *callbacks; /*!< Device state callback container for this extension */

   /*! Dev state variables */
   int laststate;       /*!< Last known device state */

   /*! Presence state variables */
   int last_presence_state;     /*!< Last known presence state */
   char *last_presence_subtype; /*!< Last known presence subtype string */
   char *last_presence_message; /*!< Last known presence message string */

   char context_name[AST_MAX_CONTEXT];/*!< Context of destroyed hint extension. */
   char exten_name[AST_MAX_EXTENSION];/*!< Extension of destroyed hint extension. */
};


#define HINTDEVICE_DATA_LENGTH 16
AST_THREADSTORAGE(hintdevice_data);

/* --- Hash tables of various objects --------*/
#ifdef LOW_MEMORY
#define HASH_EXTENHINT_SIZE 17
#else
#define HASH_EXTENHINT_SIZE 563
#endif


/*! \brief Container for hint devices */
static struct ao2_container *hintdevices;

/*!
 * \brief Structure for dial plan hint devices
 * \note hintdevice is one device pointing to a hint.
 */
struct ast_hintdevice {
   /*!
    * \brief Hint this hintdevice belongs to.
    * \note Holds a reference to the hint object.
    */
   struct ast_hint *hint;
   /*! Name of the hint device. */
   char hintdevice[1];
};


/*!
 * \note Using the device for hash
 */
static int hintdevice_hash_cb(const void *obj, const int flags)
{
   const struct ast_hintdevice *ext = obj;

   return ast_str_case_hash(ext->hintdevice);
}
/*!
 * \note Devices on hints are not unique so no CMP_STOP is returned
 * Dont use ao2_find against hintdevices container cause there always
 * could be more than one result.
 */
static int hintdevice_cmp_multiple(void *obj, void *arg, int flags)
{
   struct ast_hintdevice *ext = obj, *ext2 = arg;

   return !strcasecmp(ext->hintdevice, ext2->hintdevice) ? CMP_MATCH  : 0;
}

/*
 * \details This is used with ao2_callback to remove old devices
 * when they are linked to the hint
*/
static int hintdevice_remove_cb(void *deviceobj, void *arg, int flags)
{
   struct ast_hintdevice *device = deviceobj;
   struct ast_hint *hint = arg;

   return (device->hint == hint) ? CMP_MATCH : 0;
}

static int remove_hintdevice(struct ast_hint *hint)
{
   /* iterate through all devices and remove the devices which are linked to this hint */
   ao2_t_callback(hintdevices, OBJ_NODATA | OBJ_MULTIPLE | OBJ_UNLINK,
      hintdevice_remove_cb, hint,
      "callback to remove all devices which are linked to a hint");
   return 0;
}

static char *parse_hint_device(struct ast_str *hint_args);
/*!
 * \internal
 * \brief Destroy the given hintdevice object.
 *
 * \param obj Hint device to destroy.
 *
 * \return Nothing
 */
static void hintdevice_destroy(void *obj)
{
   struct ast_hintdevice *doomed = obj;

   if (doomed->hint) {
      ao2_ref(doomed->hint, -1);
      doomed->hint = NULL;
   }
}

/*! \brief add hintdevice structure and link it into the container.
 */
static int add_hintdevice(struct ast_hint *hint, const char *devicelist)
{
   struct ast_str *str;
   char *parse;
   char *cur;
   struct ast_hintdevice *device;
   int devicelength;

   if (!hint || !devicelist) {
      /* Trying to add garbage? Don't bother. */
      return 0;
   }
   if (!(str = ast_str_thread_get(&hintdevice_data, 16))) {
      return -1;
   }
   ast_str_set(&str, 0, "%s", devicelist);
   parse = parse_hint_device(str);

   while ((cur = strsep(&parse, "&"))) {
      devicelength = strlen(cur);
      device = ao2_t_alloc(sizeof(*device) + devicelength, hintdevice_destroy,
         "allocating a hintdevice structure");
      if (!device) {
         return -1;
      }
      strcpy(device->hintdevice, cur);
      ao2_ref(hint, +1);
      device->hint = hint;
      ao2_t_link(hintdevices, device, "Linking device into hintdevice container.");
      ao2_t_ref(device, -1, "hintdevice is linked so we can unref");
   }

   return 0;
}


static const struct cfextension_states {
   int extension_state;
   const char * const text;
} extension_states[] = {
   { AST_EXTENSION_NOT_INUSE,                     "Idle" },
   { AST_EXTENSION_INUSE,                         "InUse" },
   { AST_EXTENSION_BUSY,                          "Busy" },
   { AST_EXTENSION_UNAVAILABLE,                   "Unavailable" },
   { AST_EXTENSION_RINGING,                       "Ringing" },
   { AST_EXTENSION_INUSE | AST_EXTENSION_RINGING, "InUse&Ringing" },
   { AST_EXTENSION_ONHOLD,                        "Hold" },
   { AST_EXTENSION_INUSE | AST_EXTENSION_ONHOLD,  "InUse&Hold" }
};

struct presencechange {
   char *provider;
   int state;
   char *subtype;
   char *message;
};

struct statechange {
   AST_LIST_ENTRY(statechange) entry;
   char dev[0];
};

struct pbx_exception {
   AST_DECLARE_STRING_FIELDS(
      AST_STRING_FIELD(context); /*!< Context associated with this exception */
      AST_STRING_FIELD(exten);   /*!< Exten associated with this exception */
      AST_STRING_FIELD(reason);     /*!< The exception reason */
   );

   int priority;           /*!< Priority associated with this exception */
};

static int pbx_builtin_answer(struct ast_channel *, const char *);
static int pbx_builtin_goto(struct ast_channel *, const char *);
static int pbx_builtin_hangup(struct ast_channel *, const char *);
static int pbx_builtin_background(struct ast_channel *, const char *);
static int pbx_builtin_wait(struct ast_channel *, const char *);
static int pbx_builtin_waitexten(struct ast_channel *, const char *);
static int pbx_builtin_incomplete(struct ast_channel *, const char *);
static int pbx_builtin_resetcdr(struct ast_channel *, const char *);
static int pbx_builtin_setamaflags(struct ast_channel *, const char *);
static int pbx_builtin_ringing(struct ast_channel *, const char *);
static int pbx_builtin_proceeding(struct ast_channel *, const char *);
static int pbx_builtin_progress(struct ast_channel *, const char *);
static int pbx_builtin_congestion(struct ast_channel *, const char *);
static int pbx_builtin_busy(struct ast_channel *, const char *);
static int pbx_builtin_noop(struct ast_channel *, const char *);
static int pbx_builtin_gotoif(struct ast_channel *, const char *);
static int pbx_builtin_gotoiftime(struct ast_channel *, const char *);
static int pbx_builtin_execiftime(struct ast_channel *, const char *);
static int pbx_builtin_saynumber(struct ast_channel *, const char *);
static int pbx_builtin_saydigits(struct ast_channel *, const char *);
static int pbx_builtin_saycharacters(struct ast_channel *, const char *);
static int pbx_builtin_sayphonetic(struct ast_channel *, const char *);
static int matchcid(const char *cidpattern, const char *callerid);
#ifdef NEED_DEBUG
static void log_match_char_tree(struct match_char *node, char *prefix); /* for use anywhere */
#endif
static int pbx_builtin_importvar(struct ast_channel *, const char *);
static void set_ext_pri(struct ast_channel *c, const char *exten, int pri);
static void new_find_extension(const char *str, struct scoreboard *score,
      struct match_char *tree, int length, int spec, const char *callerid,
      const char *label, enum ext_match_t action);
static struct match_char *already_in_tree(struct match_char *current, char *pat, int is_pattern);
static struct match_char *add_exten_to_pattern_tree(struct ast_context *con,
      struct ast_exten *e1, int findonly);
static void create_match_char_tree(struct ast_context *con);
static struct ast_exten *get_canmatch_exten(struct match_char *node);
static void destroy_pattern_tree(struct match_char *pattern_tree);
static int hashtab_compare_extens(const void *ha_a, const void *ah_b);
static int hashtab_compare_exten_numbers(const void *ah_a, const void *ah_b);
static int hashtab_compare_exten_labels(const void *ah_a, const void *ah_b);
static unsigned int hashtab_hash_extens(const void *obj);
static unsigned int hashtab_hash_priority(const void *obj);
static unsigned int hashtab_hash_labels(const void *obj);
static void __ast_internal_context_destroy( struct ast_context *con);
static int ast_add_extension_nolock(const char *context, int replace, const char *extension,
   int priority, const char *label, const char *callerid,
   const char *application, void *data, void (*datad)(void *), const char *registrar);
static int ast_add_extension2_lockopt(struct ast_context *con,
   int replace, const char *extension, int priority, const char *label, const char *callerid,
   const char *application, void *data, void (*datad)(void *),
   const char *registrar, int lock_context);
static struct ast_context *find_context_locked(const char *context);
static struct ast_context *find_context(const char *context);
static void get_device_state_causing_channels(struct ao2_container *c);

/*!
 * \internal
 * \brief Character array comparison function for qsort.
 *
 * \param a Left side object.
 * \param b Right side object.
 *
 * \retval <0 if a < b
 * \retval =0 if a = b
 * \retval >0 if a > b
 */
static int compare_char(const void *a, const void *b)
{
   const unsigned char *ac = a;
   const unsigned char *bc = b;

   return *ac - *bc;
}

/* labels, contexts are case sensitive  priority numbers are ints */
int ast_hashtab_compare_contexts(const void *ah_a, const void *ah_b)
{
   const struct ast_context *ac = ah_a;
   const struct ast_context *bc = ah_b;
   if (!ac || !bc) /* safety valve, but it might prevent a crash you'd rather have happen */
      return 1;
   /* assume context names are registered in a string table! */
   return strcmp(ac->name, bc->name);
}

static int hashtab_compare_extens(const void *ah_a, const void *ah_b)
{
   const struct ast_exten *ac = ah_a;
   const struct ast_exten *bc = ah_b;
   int x = strcmp(ac->exten, bc->exten);
   if (x) { /* if exten names are diff, then return */
      return x;
   }

   /* but if they are the same, do the cidmatch values match? */
   if (ac->matchcid && bc->matchcid) {
      return strcmp(ac->cidmatch,bc->cidmatch);
   } else if (!ac->matchcid && !bc->matchcid) {
      return 0; /* if there's no matchcid on either side, then this is a match */
   } else {
      return 1; /* if there's matchcid on one but not the other, they are different */
   }
}

static int hashtab_compare_exten_numbers(const void *ah_a, const void *ah_b)
{
   const struct ast_exten *ac = ah_a;
   const struct ast_exten *bc = ah_b;
   return ac->priority != bc->priority;
}

static int hashtab_compare_exten_labels(const void *ah_a, const void *ah_b)
{
   const struct ast_exten *ac = ah_a;
   const struct ast_exten *bc = ah_b;
   return strcmp(S_OR(ac->label, ""), S_OR(bc->label, ""));
}

unsigned int ast_hashtab_hash_contexts(const void *obj)
{
   const struct ast_context *ac = obj;
   return ast_hashtab_hash_string(ac->name);
}

static unsigned int hashtab_hash_extens(const void *obj)
{
   const struct ast_exten *ac = obj;
   unsigned int x = ast_hashtab_hash_string(ac->exten);
   unsigned int y = 0;
   if (ac->matchcid)
      y = ast_hashtab_hash_string(ac->cidmatch);
   return x+y;
}

static unsigned int hashtab_hash_priority(const void *obj)
{
   const struct ast_exten *ac = obj;
   return ast_hashtab_hash_int(ac->priority);
}

static unsigned int hashtab_hash_labels(const void *obj)
{
   const struct ast_exten *ac = obj;
   return ast_hashtab_hash_string(S_OR(ac->label, ""));
}


AST_RWLOCK_DEFINE_STATIC(globalslock);
static struct varshead globals = AST_LIST_HEAD_NOLOCK_INIT_VALUE;

static int autofallthrough = 1;
static int extenpatternmatchnew = 0;
static char *overrideswitch = NULL;

/*! \brief Subscription for device state change events */
static struct ast_event_sub *device_state_sub;
/*! \brief Subscription for presence state change events */
static struct ast_event_sub *presence_state_sub;

AST_MUTEX_DEFINE_STATIC(maxcalllock);
static int countcalls;
static int totalcalls;

static AST_RWLIST_HEAD_STATIC(acf_root, ast_custom_function);

/*! \brief Declaration of builtin applications */
static struct pbx_builtin {
   char name[AST_MAX_APP];
   int (*execute)(struct ast_channel *chan, const char *data);
} builtins[] =
{
   /* These applications are built into the PBX core and do not
      need separate modules */

   { "Answer",         pbx_builtin_answer },
   { "BackGround",     pbx_builtin_background },
   { "Busy",           pbx_builtin_busy },
   { "Congestion",     pbx_builtin_congestion },
   { "ExecIfTime",     pbx_builtin_execiftime },
   { "Goto",           pbx_builtin_goto },
   { "GotoIf",         pbx_builtin_gotoif },
   { "GotoIfTime",     pbx_builtin_gotoiftime },
   { "ImportVar",      pbx_builtin_importvar },
   { "Hangup",         pbx_builtin_hangup },
   { "Incomplete",     pbx_builtin_incomplete },
   { "NoOp",           pbx_builtin_noop },
   { "Proceeding",     pbx_builtin_proceeding },
   { "Progress",       pbx_builtin_progress },
   { "RaiseException", pbx_builtin_raise_exception },
   { "ResetCDR",       pbx_builtin_resetcdr },
   { "Ringing",        pbx_builtin_ringing },
   { "SayAlpha",       pbx_builtin_saycharacters },
   { "SayDigits",      pbx_builtin_saydigits },
   { "SayNumber",      pbx_builtin_saynumber },
   { "SayPhonetic",    pbx_builtin_sayphonetic },
   { "Set",            pbx_builtin_setvar },
   { "MSet",           pbx_builtin_setvar_multiple },
   { "SetAMAFlags",    pbx_builtin_setamaflags },
   { "Wait",           pbx_builtin_wait },
   { "WaitExten",      pbx_builtin_waitexten }
};

static struct ast_context *contexts;
static struct ast_hashtab *contexts_table = NULL;

/*!
 * \brief Lock for the ast_context list
 * \note
 * This lock MUST be recursive, or a deadlock on reload may result.  See
 * https://issues.asterisk.org/view.php?id=17643
 */
AST_MUTEX_DEFINE_STATIC(conlock);

/*!
 * \brief Lock to hold off restructuring of hints by ast_merge_contexts_and_delete.
 */
AST_MUTEX_DEFINE_STATIC(context_merge_lock);

static AST_RWLIST_HEAD_STATIC(apps, ast_app);

static AST_RWLIST_HEAD_STATIC(switches, ast_switch);

static int stateid = 1;
/*!
 * \note When holding this container's lock, do _not_ do
 * anything that will cause conlock to be taken, unless you
 * _already_ hold it.  The ast_merge_contexts_and_delete function
 * will take the locks in conlock/hints order, so any other
 * paths that require both locks must also take them in that
 * order.
 */
static struct ao2_container *hints;

static struct ao2_container *statecbs;

#ifdef CONTEXT_DEBUG

/* these routines are provided for doing run-time checks
   on the extension structures, in case you are having
   problems, this routine might help you localize where
   the problem is occurring. It's kinda like a debug memory
   allocator's arena checker... It'll eat up your cpu cycles!
   but you'll see, if you call it in the right places,
   right where your problems began...
*/

/* you can break on the check_contexts_trouble()
routine in your debugger to stop at the moment
there's a problem */
void check_contexts_trouble(void);

void check_contexts_trouble(void)
{
   int x = 1;
   x = 2;
}

int check_contexts(char *, int);

int check_contexts(char *file, int line )
{
   struct ast_hashtab_iter *t1;
   struct ast_context *c1, *c2;
   int found = 0;
   struct ast_exten *e1, *e2, *e3;
   struct ast_exten ex;

   /* try to find inconsistencies */
   /* is every context in the context table in the context list and vice-versa ? */

   if (!contexts_table) {
      ast_log(LOG_NOTICE,"Called from: %s:%d: No contexts_table!\n", file, line);
      usleep(500000);
   }

   t1 = ast_hashtab_start_traversal(contexts_table);
   while( (c1 = ast_hashtab_next(t1))) {
      for(c2=contexts;c2;c2=c2->next) {
         if (!strcmp(c1->name, c2->name)) {
            found = 1;
            break;
         }
      }
      if (!found) {
         ast_log(LOG_NOTICE,"Called from: %s:%d: Could not find the %s context in the linked list\n", file, line, c1->name);
         check_contexts_trouble();
      }
   }
   ast_hashtab_end_traversal(t1);
   for(c2=contexts;c2;c2=c2->next) {
      c1 = find_context_locked(c2->name);
      if (!c1) {
         ast_log(LOG_NOTICE,"Called from: %s:%d: Could not find the %s context in the hashtab\n", file, line, c2->name);
         check_contexts_trouble();
      } else
         ast_unlock_contexts();
   }

   /* loop thru all contexts, and verify the exten structure compares to the
      hashtab structure */
   for(c2=contexts;c2;c2=c2->next) {
      c1 = find_context_locked(c2->name);
      if (c1) {
         ast_unlock_contexts();

         /* is every entry in the root list also in the root_table? */
         for(e1 = c1->root; e1; e1=e1->next)
         {
            char dummy_name[1024];
            ex.exten = dummy_name;
            ex.matchcid = e1->matchcid;
            ex.cidmatch = e1->cidmatch;
            ast_copy_string(dummy_name, e1->exten, sizeof(dummy_name));
            e2 = ast_hashtab_lookup(c1->root_table, &ex);
            if (!e2) {
               if (e1->matchcid) {
                  ast_log(LOG_NOTICE,"Called from: %s:%d: The %s context records the exten %s (CID match: %s) but it is not in its root_table\n", file, line, c2->name, dummy_name, e1->cidmatch );
               } else {
                  ast_log(LOG_NOTICE,"Called from: %s:%d: The %s context records the exten %s but it is not in its root_table\n", file, line, c2->name, dummy_name );
               }
               check_contexts_trouble();
            }
         }

         /* is every entry in the root_table also in the root list? */
         if (!c2->root_table) {
            if (c2->root) {
               ast_log(LOG_NOTICE,"Called from: %s:%d: No c2->root_table for context %s!\n", file, line, c2->name);
               usleep(500000);
            }
         } else {
            t1 = ast_hashtab_start_traversal(c2->root_table);
            while( (e2 = ast_hashtab_next(t1)) ) {
               for(e1=c2->root;e1;e1=e1->next) {
                  if (!strcmp(e1->exten, e2->exten)) {
                     found = 1;
                     break;
                  }
               }
               if (!found) {
                  ast_log(LOG_NOTICE,"Called from: %s:%d: The %s context records the exten %s but it is not in its root_table\n", file, line, c2->name, e2->exten);
                  check_contexts_trouble();
               }

            }
            ast_hashtab_end_traversal(t1);
         }
      }
      /* is every priority reflected in the peer_table at the head of the list? */

      /* is every entry in the root list also in the root_table? */
      /* are the per-extension peer_tables in the right place? */

      for(e1 = c2->root; e1; e1 = e1->next) {

         for(e2=e1;e2;e2=e2->peer) {
            ex.priority = e2->priority;
            if (e2 != e1 && e2->peer_table) {
               ast_log(LOG_NOTICE,"Called from: %s:%d: The %s context, %s exten, %d priority has a peer_table entry, and shouldn't!\n", file, line, c2->name, e1->exten, e2->priority );
               check_contexts_trouble();
            }

            if (e2 != e1 && e2->peer_label_table) {
               ast_log(LOG_NOTICE,"Called from: %s:%d: The %s context, %s exten, %d priority has a peer_label_table entry, and shouldn't!\n", file, line, c2->name, e1->exten, e2->priority );
               check_contexts_trouble();
            }

            if (e2 == e1 && !e2->peer_table){
               ast_log(LOG_NOTICE,"Called from: %s:%d: The %s context, %s exten, %d priority doesn't have a peer_table!\n", file, line, c2->name, e1->exten, e2->priority );
               check_contexts_trouble();
            }

            if (e2 == e1 && !e2->peer_label_table) {
               ast_log(LOG_NOTICE,"Called from: %s:%d: The %s context, %s exten, %d priority doesn't have a peer_label_table!\n", file, line, c2->name, e1->exten, e2->priority );
               check_contexts_trouble();
            }


            e3 = ast_hashtab_lookup(e1->peer_table, &ex);
            if (!e3) {
               ast_log(LOG_NOTICE,"Called from: %s:%d: The %s context, %s exten, %d priority is not reflected in the peer_table\n", file, line, c2->name, e1->exten, e2->priority );
               check_contexts_trouble();
            }
         }

         if (!e1->peer_table){
            ast_log(LOG_NOTICE,"Called from: %s:%d: No e1->peer_table!\n", file, line);
            usleep(500000);
         }

         /* is every entry in the peer_table also in the peer list? */
         t1 = ast_hashtab_start_traversal(e1->peer_table);
         while( (e2 = ast_hashtab_next(t1)) ) {
            for(e3=e1;e3;e3=e3->peer) {
               if (e3->priority == e2->priority) {
                  found = 1;
                  break;
               }
            }
            if (!found) {
               ast_log(LOG_NOTICE,"Called from: %s:%d: The %s context, %s exten, %d priority is not reflected in the peer list\n", file, line, c2->name, e1->exten, e2->priority );
               check_contexts_trouble();
            }
         }
         ast_hashtab_end_traversal(t1);
      }
   }
   return 0;
}
#endif

/*
   \note This function is special. It saves the stack so that no matter
   how many times it is called, it returns to the same place */
int pbx_exec(struct ast_channel *c, /*!< Channel */
        struct ast_app *app,  /*!< Application */
        const char *data)     /*!< Data for execution */
{
   int res;
   struct ast_module_user *u = NULL;
   const char *saved_c_appl;
   const char *saved_c_data;

   if (ast_channel_cdr(c) && !ast_check_hangup(c))
      ast_cdr_setapp(ast_channel_cdr(c), app->name, data);

   /* save channel values */
   saved_c_appl= ast_channel_appl(c);
   saved_c_data= ast_channel_data(c);

   ast_channel_appl_set(c, app->name);
   ast_channel_data_set(c, data);
   ast_cel_report_event(c, AST_CEL_APP_START, NULL, NULL, NULL);

   if (app->module)
      u = __ast_module_user_add(app->module, c);
   if (strcasecmp(app->name, "system") && !ast_strlen_zero(data) &&
         strchr(data, '|') && !strchr(data, ',') && !ast_opt_dont_warn) {
      ast_log(LOG_WARNING, "The application delimiter is now the comma, not "
         "the pipe.  Did you forget to convert your dialplan?  (%s(%s))\n",
         app->name, (char *) data);
   }
   res = app->execute(c, S_OR(data, ""));
   if (app->module && u)
      __ast_module_user_remove(app->module, u);
   ast_cel_report_event(c, AST_CEL_APP_END, NULL, NULL, NULL);
   /* restore channel values */
   ast_channel_appl_set(c, saved_c_appl);
   ast_channel_data_set(c, saved_c_data);
   return res;
}


/*! Go no deeper than this through includes (not counting loops) */
#define AST_PBX_MAX_STACK  128

/*! \brief Find application handle in linked list
 */
struct ast_app *pbx_findapp(const char *app)
{
   struct ast_app *tmp;

   AST_RWLIST_RDLOCK(&apps);
   AST_RWLIST_TRAVERSE(&apps, tmp, list) {
      if (!strcasecmp(tmp->name, app))
         break;
   }
   AST_RWLIST_UNLOCK(&apps);

   return tmp;
}

static struct ast_switch *pbx_findswitch(const char *sw)
{
   struct ast_switch *asw;

   AST_RWLIST_RDLOCK(&switches);
   AST_RWLIST_TRAVERSE(&switches, asw, list) {
      if (!strcasecmp(asw->name, sw))
         break;
   }
   AST_RWLIST_UNLOCK(&switches);

   return asw;
}

static inline int include_valid(struct ast_include *i)
{
   if (!i->hastime)
      return 1;

   return ast_check_timing(&(i->timing));
}

static void pbx_destroy(struct ast_pbx *p)
{
   ast_free(p);
}

/* form a tree that fully describes all the patterns in a context's extensions
 * in this tree, a "node" represents an individual character or character set
 * meant to match the corresponding character in a dial string. The tree
 * consists of a series of match_char structs linked in a chain
 * via the alt_char pointers. More than one pattern can share the same parts of the
 * tree as other extensions with the same pattern to that point.
 * My first attempt to duplicate the finding of the 'best' pattern was flawed in that
 * I misunderstood the general algorithm. I thought that the 'best' pattern
 * was the one with lowest total score. This was not true. Thus, if you have
 * patterns "1XXXXX" and "X11111", you would be tempted to say that "X11111" is
 * the "best" match because it has fewer X's, and is therefore more specific,
 * but this is not how the old algorithm works. It sorts matching patterns
 * in a similar collating sequence as sorting alphabetic strings, from left to
 * right. Thus, "1XXXXX" comes before "X11111", and would be the "better" match,
 * because "1" is more specific than "X".
 * So, to accomodate this philosophy, I sort the tree branches along the alt_char
 * line so they are lowest to highest in specificity numbers. This way, as soon
 * as we encounter our first complete match, we automatically have the "best"
 * match and can stop the traversal immediately. Same for CANMATCH/MATCHMORE.
 * If anyone would like to resurrect the "wrong" pattern trie searching algorithm,
 * they are welcome to revert pbx to before 1 Apr 2008.
 * As an example, consider these 4 extensions:
 * (a) NXXNXXXXXX
 * (b) 307754XXXX
 * (c) fax
 * (d) NXXXXXXXXX
 *
 * In the above, between (a) and (d), (a) is a more specific pattern than (d), and would win over
 * most numbers. For all numbers beginning with 307754, (b) should always win.
 *
 * These pattern should form a (sorted) tree that looks like this:
 *   { "3" }  --next-->  { "0" }  --next--> { "7" } --next--> { "7" } --next--> { "5" } ... blah ... --> { "X" exten_match: (b) }
 *      |
 *      |alt
 *      |
 *   { "f" }  --next-->  { "a" }  --next--> { "x"  exten_match: (c) }
 *   { "N" }  --next-->  { "X" }  --next--> { "X" } --next--> { "N" } --next--> { "X" } ... blah ... --> { "X" exten_match: (a) }
 *      |                                                        |
 *      |                                                        |alt
 *      |alt                                                     |
 *      |                                                     { "X" } --next--> { "X" } ... blah ... --> { "X" exten_match: (d) }
 *      |
 *     NULL
 *
 *   In the above, I could easily turn "N" into "23456789", but I think that a quick "if( *z >= '2' && *z <= '9' )" might take
 *   fewer CPU cycles than a call to strchr("23456789",*z), where *z is the char to match...
 *
 *   traversal is pretty simple: one routine merely traverses the alt list, and for each matching char in the pattern,  it calls itself
 *   on the corresponding next pointer, incrementing also the pointer of the string to be matched, and passing the total specificity and length.
 *   We pass a pointer to a scoreboard down through, also.
 *   The scoreboard isn't as necessary to the revised algorithm, but I kept it as a handy way to return the matched extension.
 *   The first complete match ends the traversal, which should make this version of the pattern matcher faster
 *   the previous. The same goes for "CANMATCH" or "MATCHMORE"; the first such match ends the traversal. In both
 *   these cases, the reason we can stop immediately, is because the first pattern match found will be the "best"
 *   according to the sort criteria.
 *   Hope the limit on stack depth won't be a problem... this routine should
 *   be pretty lean as far a stack usage goes. Any non-match terminates the recursion down a branch.
 *
 *   In the above example, with the number "3077549999" as the pattern, the traversor could match extensions a, b and d.  All are
 *   of length 10; they have total specificities of  24580, 10246, and 25090, respectively, not that this matters
 *   at all. (b) wins purely because the first character "3" is much more specific (lower specificity) than "N". I have
 *   left the specificity totals in the code as an artifact; at some point, I will strip it out.
 *
 *   Just how much time this algorithm might save over a plain linear traversal over all possible patterns is unknown,
 *   because it's a function of how many extensions are stored in a context. With thousands of extensions, the speedup
 *   can be very noticeable. The new matching algorithm can run several hundreds of times faster, if not a thousand or
 *   more times faster in extreme cases.
 *
 *   MatchCID patterns are also supported, and stored in the tree just as the extension pattern is. Thus, you
 *   can have patterns in your CID field as well.
 *
 * */


static void update_scoreboard(struct scoreboard *board, int length, int spec, struct ast_exten *exten, char last, const char *callerid, int deleted, struct match_char *node)
{
   /* if this extension is marked as deleted, then skip this -- if it never shows
      on the scoreboard, it will never be found, nor will halt the traversal. */
   if (deleted)
      return;
   board->total_specificity = spec;
   board->total_length = length;
   board->exten = exten;
   board->last_char = last;
   board->node = node;
#ifdef NEED_DEBUG_HERE
   ast_log(LOG_NOTICE,"Scoreboarding (LONGER) %s, len=%d, score=%d\n", exten->exten, length, spec);
#endif
}

#ifdef NEED_DEBUG
static void log_match_char_tree(struct match_char *node, char *prefix)
{
   char extenstr[40];
   struct ast_str *my_prefix = ast_str_alloca(1024);

   extenstr[0] = '\0';

   if (node && node->exten)
      snprintf(extenstr, sizeof(extenstr), "(%p)", node->exten);

   if (strlen(node->x) > 1) {
      ast_debug(1, "%s[%s]:%c:%c:%d:%s%s%s\n", prefix, node->x, node->is_pattern ? 'Y':'N',
         node->deleted? 'D':'-', node->specificity, node->exten? "EXTEN:":"",
         node->exten ? node->exten->exten : "", extenstr);
   } else {
      ast_debug(1, "%s%s:%c:%c:%d:%s%s%s\n", prefix, node->x, node->is_pattern ? 'Y':'N',
         node->deleted? 'D':'-', node->specificity, node->exten? "EXTEN:":"",
         node->exten ? node->exten->exten : "", extenstr);
   }

   ast_str_set(&my_prefix, 0, "%s+       ", prefix);

   if (node->next_char)
      log_match_char_tree(node->next_char, ast_str_buffer(my_prefix));

   if (node->alt_char)
      log_match_char_tree(node->alt_char, prefix);
}
#endif

static void cli_match_char_tree(struct match_char *node, char *prefix, int fd)
{
   char extenstr[40];
   struct ast_str *my_prefix = ast_str_alloca(1024);

   extenstr[0] = '\0';

   if (node->exten) {
      snprintf(extenstr, sizeof(extenstr), "(%p)", node->exten);
   }

   if (strlen(node->x) > 1) {
      ast_cli(fd, "%s[%s]:%c:%c:%d:%s%s%s\n", prefix, node->x, node->is_pattern ? 'Y' : 'N',
         node->deleted ? 'D' : '-', node->specificity, node->exten? "EXTEN:" : "",
         node->exten ? node->exten->exten : "", extenstr);
   } else {
      ast_cli(fd, "%s%s:%c:%c:%d:%s%s%s\n", prefix, node->x, node->is_pattern ? 'Y' : 'N',
         node->deleted ? 'D' : '-', node->specificity, node->exten? "EXTEN:" : "",
         node->exten ? node->exten->exten : "", extenstr);
   }

   ast_str_set(&my_prefix, 0, "%s+       ", prefix);

   if (node->next_char)
      cli_match_char_tree(node->next_char, ast_str_buffer(my_prefix), fd);

   if (node->alt_char)
      cli_match_char_tree(node->alt_char, prefix, fd);
}

static struct ast_exten *get_canmatch_exten(struct match_char *node)
{
   /* find the exten at the end of the rope */
   struct match_char *node2 = node;

   for (node2 = node; node2; node2 = node2->next_char) {
      if (node2->exten) {
#ifdef NEED_DEBUG_HERE
         ast_log(LOG_NOTICE,"CanMatch_exten returns exten %s(%p)\n", node2->exten->exten, node2->exten);
#endif
         return node2->exten;
      }
   }
#ifdef NEED_DEBUG_HERE
   ast_log(LOG_NOTICE,"CanMatch_exten returns NULL, match_char=%s\n", node->x);
#endif
   return 0;
}

static struct ast_exten *trie_find_next_match(struct match_char *node)
{
   struct match_char *m3;
   struct match_char *m4;
   struct ast_exten *e3;

   if (node && node->x[0] == '.' && !node->x[1]) { /* dot and ! will ALWAYS be next match in a matchmore */
      return node->exten;
   }

   if (node && node->x[0] == '!' && !node->x[1]) {
      return node->exten;
   }

   if (!node || !node->next_char) {
      return NULL;
   }

   m3 = node->next_char;

   if (m3->exten) {
      return m3->exten;
   }
   for (m4 = m3->alt_char; m4; m4 = m4->alt_char) {
      if (m4->exten) {
         return m4->exten;
      }
   }
   for (m4 = m3; m4; m4 = m4->alt_char) {
      e3 = trie_find_next_match(m3);
      if (e3) {
         return e3;
      }
   }

   return NULL;
}

#ifdef DEBUG_THIS
static char *action2str(enum ext_match_t action)
{
   switch (action) {
   case E_MATCH:
      return "MATCH";
   case E_CANMATCH:
      return "CANMATCH";
   case E_MATCHMORE:
      return "MATCHMORE";
   case E_FINDLABEL:
      return "FINDLABEL";
   case E_SPAWN:
      return "SPAWN";
   default:
      return "?ACTION?";
   }
}

#endif

static void new_find_extension(const char *str, struct scoreboard *score, struct match_char *tree, int length, int spec, const char *callerid, const char *label, enum ext_match_t action)
{
   struct match_char *p; /* note minimal stack storage requirements */
   struct ast_exten pattern = { .label = label };
#ifdef DEBUG_THIS
   if (tree)
      ast_log(LOG_NOTICE,"new_find_extension called with %s on (sub)tree %s action=%s\n", str, tree->x, action2str(action));
   else
      ast_log(LOG_NOTICE,"new_find_extension called with %s on (sub)tree NULL action=%s\n", str, action2str(action));
#endif
   for (p = tree; p; p = p->alt_char) {
      if (p->is_pattern) {
         if (p->x[0] == 'N') {
            if (p->x[1] == 0 && *str >= '2' && *str <= '9' ) {
#define  NEW_MATCHER_CHK_MATCH          \
               if (p->exten && !(*(str + 1))) { /* if a shorter pattern matches along the way, might as well report it */             \
                  if (action == E_MATCH || action == E_SPAWN || action == E_FINDLABEL) { /* if in CANMATCH/MATCHMORE, don't let matches get in the way */   \
                     update_scoreboard(score, length + 1, spec + p->specificity, p->exten, 0, callerid, p->deleted, p);                 \
                     if (!p->deleted) {                                                                                           \
                        if (action == E_FINDLABEL) {                                                                             \
                           if (ast_hashtab_lookup(score->exten->peer_label_table, &pattern)) {                                  \
                              ast_debug(4, "Found label in preferred extension\n");                                            \
                              return;                                                                                          \
                           }                                                                                                    \
                        } else {                                                                                                 \
                           ast_debug(4, "returning an exact match-- first found-- %s\n", p->exten->exten);                       \
                           return; /* the first match, by definition, will be the best, because of the sorted tree */           \
                        }                                                                                                        \
                     }                                                                                                            \
                  }                                                                                                                \
               }

#define  NEW_MATCHER_RECURSE             \
               if (p->next_char && (*(str + 1) || (p->next_char->x[0] == '/' && p->next_char->x[1] == 0)                 \
                                             || p->next_char->x[0] == '!')) {                                          \
                  if (*(str + 1) || p->next_char->x[0] == '!') {                                                         \
                     new_find_extension(str + 1, score, p->next_char, length + 1, spec + p->specificity, callerid, label, action); \
                     if (score->exten)  {                                                                             \
                          ast_debug(4 ,"returning an exact match-- %s\n", score->exten->exten);                         \
                        return; /* the first match is all we need */                                                 \
                     }                                                                                    \
                  } else {                                                                                             \
                     new_find_extension("/", score, p->next_char, length + 1, spec + p->specificity, callerid, label, action);    \
                     if (score->exten || ((action == E_CANMATCH || action == E_MATCHMORE) && score->canmatch)) {      \
                          ast_debug(4,"returning a (can/more) match--- %s\n", score->exten ? score->exten->exten :     \
                                     "NULL");                                                                        \
                        return; /* the first match is all we need */                                                 \
                     }                                                                                    \
                  }                                                                                                    \
               } else if ((p->next_char || action == E_CANMATCH) && !*(str + 1)) {                                                                  \
                  score->canmatch = 1;                                                                                 \
                  score->canmatch_exten = get_canmatch_exten(p);                                                       \
                  if (action == E_CANMATCH || action == E_MATCHMORE) {                                                 \
                       ast_debug(4, "returning a canmatch/matchmore--- str=%s\n", str);                                  \
                     return;                                                                                          \
                  }                                                                                        \
               }

               NEW_MATCHER_CHK_MATCH;
               NEW_MATCHER_RECURSE;
            }
         } else if (p->x[0] == 'Z') {
            if (p->x[1] == 0 && *str >= '1' && *str <= '9' ) {
               NEW_MATCHER_CHK_MATCH;
               NEW_MATCHER_RECURSE;
            }
         } else if (p->x[0] == 'X') {
            if (p->x[1] == 0 && *str >= '0' && *str <= '9' ) {
               NEW_MATCHER_CHK_MATCH;
               NEW_MATCHER_RECURSE;
            }
         } else if (p->x[0] == '.' && p->x[1] == 0) {
            /* how many chars will the . match against? */
            int i = 0;
            const char *str2 = str;
            while (*str2 && *str2 != '/') {
               str2++;
               i++;
            }
            if (p->exten && *str2 != '/') {
               update_scoreboard(score, length + i, spec + (i * p->specificity), p->exten, '.', callerid, p->deleted, p);
               if (score->exten) {
                  ast_debug(4,"return because scoreboard has a match with '/'--- %s\n", score->exten->exten);
                  return; /* the first match is all we need */
               }
            }
            if (p->next_char && p->next_char->x[0] == '/' && p->next_char->x[1] == 0) {
               new_find_extension("/", score, p->next_char, length + i, spec+(p->specificity*i), callerid, label, action);
               if (score->exten || ((action == E_CANMATCH || action == E_MATCHMORE) && score->canmatch)) {
                  ast_debug(4, "return because scoreboard has exact match OR CANMATCH/MATCHMORE & canmatch set--- %s\n", score->exten ? score->exten->exten : "NULL");
                  return; /* the first match is all we need */
               }
            }
         } else if (p->x[0] == '!' && p->x[1] == 0) {
            /* how many chars will the . match against? */
            int i = 1;
            const char *str2 = str;
            while (*str2 && *str2 != '/') {
               str2++;
               i++;
            }
            if (p->exten && *str2 != '/') {
               update_scoreboard(score, length + 1, spec + (p->specificity * i), p->exten, '!', callerid, p->deleted, p);
               if (score->exten) {
                  ast_debug(4, "return because scoreboard has a '!' match--- %s\n", score->exten->exten);
                  return; /* the first match is all we need */
               }
            }
            if (p->next_char && p->next_char->x[0] == '/' && p->next_char->x[1] == 0) {
               new_find_extension("/", score, p->next_char, length + i, spec + (p->specificity * i), callerid, label, action);
               if (score->exten || ((action == E_CANMATCH || action == E_MATCHMORE) && score->canmatch)) {
                  ast_debug(4, "return because scoreboard has exact match OR CANMATCH/MATCHMORE & canmatch set with '/' and '!'--- %s\n", score->exten ? score->exten->exten : "NULL");
                  return; /* the first match is all we need */
               }
            }
         } else if (p->x[0] == '/' && p->x[1] == 0) {
            /* the pattern in the tree includes the cid match! */
            if (p->next_char && callerid && *callerid) {
               new_find_extension(callerid, score, p->next_char, length + 1, spec, callerid, label, action);
               if (score->exten || ((action == E_CANMATCH || action == E_MATCHMORE) && score->canmatch)) {
                  ast_debug(4, "return because scoreboard has exact match OR CANMATCH/MATCHMORE & canmatch set with '/'--- %s\n", score->exten ? score->exten->exten : "NULL");
                  return; /* the first match is all we need */
               }
            }
         } else if (strchr(p->x, *str)) {
            ast_debug(4, "Nothing strange about this match\n");
            NEW_MATCHER_CHK_MATCH;
            NEW_MATCHER_RECURSE;
         }
      } else if (strchr(p->x, *str)) {
         ast_debug(4, "Nothing strange about this match\n");
         NEW_MATCHER_CHK_MATCH;
         NEW_MATCHER_RECURSE;
      }
   }
   ast_debug(4, "return at end of func\n");
}

/* the algorithm for forming the extension pattern tree is also a bit simple; you
 * traverse all the extensions in a context, and for each char of the extension,
 * you see if it exists in the tree; if it doesn't, you add it at the appropriate
 * spot. What more can I say? At the end of each exten, you cap it off by adding the
 * address of the extension involved. Duplicate patterns will be complained about.
 *
 * Ideally, this would be done for each context after it is created and fully
 * filled. It could be done as a finishing step after extensions.conf or .ael is
 * loaded, or it could be done when the first search is encountered. It should only
 * have to be done once, until the next unload or reload.
 *
 * I guess forming this pattern tree would be analogous to compiling a regex. Except
 * that a regex only handles 1 pattern, really. This trie holds any number
 * of patterns. Well, really, it **could** be considered a single pattern,
 * where the "|" (or) operator is allowed, I guess, in a way, sort of...
 */

static struct match_char *already_in_tree(struct match_char *current, char *pat, int is_pattern)
{
   struct match_char *t;

   if (!current) {
      return 0;
   }

   for (t = current; t; t = t->alt_char) {
      if (is_pattern == t->is_pattern && !strcmp(pat, t->x)) {/* uh, we may want to sort exploded [] contents to make matching easy */
         return t;
      }
   }

   return 0;
}

/* The first arg is the location of the tree ptr, or the
   address of the next_char ptr in the node, so we can mess
   with it, if we need to insert at the beginning of the list */

static void insert_in_next_chars_alt_char_list(struct match_char **parent_ptr, struct match_char *node)
{
   struct match_char *curr, *lcurr;

   /* insert node into the tree at "current", so the alt_char list from current is
      sorted in increasing value as you go to the leaves */
   if (!(*parent_ptr)) {
      *parent_ptr = node;
      return;
   }

   if ((*parent_ptr)->specificity > node->specificity) {
      /* insert at head */
      node->alt_char = (*parent_ptr);
      *parent_ptr = node;
      return;
   }

   lcurr = *parent_ptr;
   for (curr = (*parent_ptr)->alt_char; curr; curr = curr->alt_char) {
      if (curr->specificity > node->specificity) {
         node->alt_char = curr;
         lcurr->alt_char = node;
         break;
      }
      lcurr = curr;
   }

   if (!curr) {
      lcurr->alt_char = node;
   }

}

struct pattern_node {
   /*! Pattern node specificity */
   int specif;
   /*! Pattern node match characters. */
   char buf[256];
};

static struct match_char *add_pattern_node(struct ast_context *con, struct match_char *current, const struct pattern_node *pattern, int is_pattern, int already, struct match_char **nextcharptr)
{
   struct match_char *m;

   if (!(m = ast_calloc(1, sizeof(*m) + strlen(pattern->buf)))) {
      return NULL;
   }

   /* strcpy is safe here since we know its size and have allocated
    * just enough space for when we allocated m
    */
   strcpy(m->x, pattern->buf);

   /* the specificity scores are the same as used in the old
      pattern matcher. */
   m->is_pattern = is_pattern;
   if (pattern->specif == 1 && is_pattern && pattern->buf[0] == 'N') {
      m->specificity = 0x0832;
   } else if (pattern->specif == 1 && is_pattern && pattern->buf[0] == 'Z') {
      m->specificity = 0x0931;
   } else if (pattern->specif == 1 && is_pattern && pattern->buf[0] == 'X') {
      m->specificity = 0x0a30;
   } else if (pattern->specif == 1 && is_pattern && pattern->buf[0] == '.') {
      m->specificity = 0x18000;
   } else if (pattern->specif == 1 && is_pattern && pattern->buf[0] == '!') {
      m->specificity = 0x28000;
   } else {
      m->specificity = pattern->specif;
   }

   if (!con->pattern_tree) {
      insert_in_next_chars_alt_char_list(&con->pattern_tree, m);
   } else {
      if (already) { /* switch to the new regime (traversing vs appending)*/
         insert_in_next_chars_alt_char_list(nextcharptr, m);
      } else {
         insert_in_next_chars_alt_char_list(&current->next_char, m);
      }
   }

   return m;
}

/*!
 * \internal
 * \brief Extract the next exten pattern node.
 *
 * \param node Pattern node to fill.
 * \param src Next source character to read.
 * \param pattern TRUE if the exten is a pattern.
 * \param extenbuf Original exten buffer to use in diagnostic messages.
 *
 * \retval Ptr to next extenbuf pos to read.
 */
static const char *get_pattern_node(struct pattern_node *node, const char *src, int pattern, const char *extenbuf)
{
#define INC_DST_OVERFLOW_CHECK                     \
   do {                                   \
      if (dst - node->buf < sizeof(node->buf) - 1) {  \
         ++dst;                              \
      } else {                            \
         overflow = 1;                       \
      }                                   \
   } while (0)

   node->specif = 0;
   node->buf[0] = '\0';
   while (*src) {
      if (*src == '[' && pattern) {
         char *dst = node->buf;
         const char *src_next;
         int length;
         int overflow = 0;

         /* get past the '[' */
         ++src;
         for (;;) {
            if (*src == '\\') {
               /* Escaped character. */
               ++src;
               if (*src == '[' || *src == '\\' || *src == '-' || *src == ']') {
                  *dst = *src++;
                  INC_DST_OVERFLOW_CHECK;
               }
            } else if (*src == '-') {
               unsigned char first;
               unsigned char last;

               src_next = src;
               first = *(src_next - 1);
               last = *++src_next;

               if (last == '\\') {
                  /* Escaped character. */
                  last = *++src_next;
               }

               /* Possible char range. */
               if (node->buf[0] && last) {
                  /* Expand the char range. */
                  while (++first <= last) {
                     *dst = first;
                     INC_DST_OVERFLOW_CHECK;
                  }
                  src = src_next + 1;
               } else {
                  /*
                   * There was no left or right char for the range.
                   * It is just a '-'.
                   */
                  *dst = *src++;
                  INC_DST_OVERFLOW_CHECK;
               }
            } else if (*src == '\0') {
               ast_log(LOG_WARNING,
                  "A matching ']' was not found for '[' in exten pattern '%s'\n",
                  extenbuf);
               break;
            } else if (*src == ']') {
               ++src;
               break;
            } else {
               *dst = *src++;
               INC_DST_OVERFLOW_CHECK;
            }
         }
         /* null terminate the exploded range */
         *dst = '\0';

         if (overflow) {
            ast_log(LOG_ERROR,
               "Expanded character set too large to deal with in exten pattern '%s'. Ignoring character set.\n",
               extenbuf);
            node->buf[0] = '\0';
            continue;
         }

         /* Sort the characters in character set. */
         length = strlen(node->buf);
         if (!length) {
            ast_log(LOG_WARNING, "Empty character set in exten pattern '%s'. Ignoring.\n",
               extenbuf);
            node->buf[0] = '\0';
            continue;
         }
         qsort(node->buf, length, 1, compare_char);

         /* Remove duplicate characters from character set. */
         dst = node->buf;
         src_next = node->buf;
         while (*src_next++) {
            if (*dst != *src_next) {
               *++dst = *src_next;
            }
         }

         length = strlen(node->buf);
         length <<= 8;
         node->specif = length | (unsigned char) node->buf[0];
         break;
      } else if (*src == '-') {
         /* Skip dashes in all extensions. */
         ++src;
      } else {
         if (*src == '\\') {
            /*
             * XXX The escape character here does not remove any special
             * meaning to characters except the '[', '\\', and '-'
             * characters since they are special only in this function.
             */
            node->buf[0] = *++src;
            if (!node->buf[0]) {
               break;
            }
         } else {
            node->buf[0] = *src;
            if (pattern) {
               /* make sure n,x,z patterns are canonicalized to N,X,Z */
               if (node->buf[0] == 'n') {
                  node->buf[0] = 'N';
               } else if (node->buf[0] == 'x') {
                  node->buf[0] = 'X';
               } else if (node->buf[0] == 'z') {
                  node->buf[0] = 'Z';
               }
            }
         }
         node->buf[1] = '\0';
         node->specif = 1;
         ++src;
         break;
      }
   }
   return src;

#undef INC_DST_OVERFLOW_CHECK
}

static struct match_char *add_exten_to_pattern_tree(struct ast_context *con, struct ast_exten *e1, int findonly)
{
   struct match_char *m1 = NULL;
   struct match_char *m2 = NULL;
   struct match_char **m0;
   const char *pos;
   int already;
   int pattern = 0;
   int idx_cur;
   int idx_next;
   char extenbuf[512];
   struct pattern_node pat_node[2];

   if (e1->matchcid) {
      if (sizeof(extenbuf) < strlen(e1->exten) + strlen(e1->cidmatch) + 2) {
         ast_log(LOG_ERROR,
            "The pattern %s/%s is too big to deal with: it will be ignored! Disaster!\n",
            e1->exten, e1->cidmatch);
         return NULL;
      }
      sprintf(extenbuf, "%s/%s", e1->exten, e1->cidmatch);/* Safe.  We just checked. */
   } else {
      ast_copy_string(extenbuf, e1->exten, sizeof(extenbuf));
   }

#ifdef NEED_DEBUG
   ast_debug(1, "Adding exten %s to tree\n", extenbuf);
#endif
   m1 = con->pattern_tree; /* each pattern starts over at the root of the pattern tree */
   m0 = &con->pattern_tree;
   already = 1;

   pos = extenbuf;
   if (*pos == '_') {
      pattern = 1;
      ++pos;
   }
   idx_cur = 0;
   pos = get_pattern_node(&pat_node[idx_cur], pos, pattern, extenbuf);
   for (; pat_node[idx_cur].buf[0]; idx_cur = idx_next) {
      idx_next = (idx_cur + 1) % ARRAY_LEN(pat_node);
      pos = get_pattern_node(&pat_node[idx_next], pos, pattern, extenbuf);

      /* See about adding node to tree. */
      m2 = NULL;
      if (already && (m2 = already_in_tree(m1, pat_node[idx_cur].buf, pattern))
         && m2->next_char) {
         if (!pat_node[idx_next].buf[0]) {
            /*
             * This is the end of the pattern, but not the end of the tree.
             * Mark this node with the exten... a shorter pattern might win
             * if the longer one doesn't match.
             */
            if (findonly) {
               return m2;
            }
            if (m2->exten) {
               ast_log(LOG_WARNING, "Found duplicate exten. Had %s found %s\n",
                  m2->deleted ? "(deleted/invalid)" : m2->exten->exten, e1->exten);
            }
            m2->exten = e1;
            m2->deleted = 0;
         }
         m1 = m2->next_char; /* m1 points to the node to compare against */
         m0 = &m2->next_char; /* m0 points to the ptr that points to m1 */
      } else { /* not already OR not m2 OR nor m2->next_char */
         if (m2) {
            if (findonly) {
               return m2;
            }
            m1 = m2; /* while m0 stays the same */
         } else {
            if (findonly) {
               return m1;
            }
            m1 = add_pattern_node(con, m1, &pat_node[idx_cur], pattern, already, m0);
            if (!m1) { /* m1 is the node just added */
               return NULL;
            }
            m0 = &m1->next_char;
         }
         if (!pat_node[idx_next].buf[0]) {
            if (m2 && m2->exten) {
               ast_log(LOG_WARNING, "Found duplicate exten. Had %s found %s\n",
                  m2->deleted ? "(deleted/invalid)" : m2->exten->exten, e1->exten);
            }
            m1->deleted = 0;
            m1->exten = e1;
         }

         /* The 'already' variable is a mini-optimization designed to make it so that we
          * don't have to call already_in_tree when we know it will return false.
          */
         already = 0;
      }
   }
   return m1;
}

static void create_match_char_tree(struct ast_context *con)
{
   struct ast_hashtab_iter *t1;
   struct ast_exten *e1;
#ifdef NEED_DEBUG
   int biggest_bucket, resizes, numobjs, numbucks;

   ast_debug(1, "Creating Extension Trie for context %s(%p)\n", con->name, con);
   ast_hashtab_get_stats(con->root_table, &biggest_bucket, &resizes, &numobjs, &numbucks);
   ast_debug(1, "This tree has %d objects in %d bucket lists, longest list=%d objects, and has resized %d times\n",
         numobjs, numbucks, biggest_bucket, resizes);
#endif
   t1 = ast_hashtab_start_traversal(con->root_table);
   while ((e1 = ast_hashtab_next(t1))) {
      if (e1->exten) {
         add_exten_to_pattern_tree(con, e1, 0);
      } else {
         ast_log(LOG_ERROR, "Attempt to create extension with no extension name.\n");
      }
   }
   ast_hashtab_end_traversal(t1);
}

static void destroy_pattern_tree(struct match_char *pattern_tree) /* pattern tree is a simple binary tree, sort of, so the proper way to destroy it is... recursively! */
{
   /* destroy all the alternates */
   if (pattern_tree->alt_char) {
      destroy_pattern_tree(pattern_tree->alt_char);
      pattern_tree->alt_char = 0;
   }
   /* destroy all the nexts */
   if (pattern_tree->next_char) {
      destroy_pattern_tree(pattern_tree->next_char);
      pattern_tree->next_char = 0;
   }
   pattern_tree->exten = 0; /* never hurts to make sure there's no pointers laying around */
   ast_free(pattern_tree);
}

/*
 * Special characters used in patterns:
 * '_'   underscore is the leading character of a pattern.
 *    In other position it is treated as a regular char.
 * .  one or more of any character. Only allowed at the end of
 *    a pattern.
 * !  zero or more of anything. Also impacts the result of CANMATCH
 *    and MATCHMORE. Only allowed at the end of a pattern.
 *    In the core routine, ! causes a match with a return code of 2.
 *    In turn, depending on the search mode: (XXX check if it is implemented)
 *    - E_MATCH retuns 1 (does match)
 *    - E_MATCHMORE returns 0 (no match)
 *    - E_CANMATCH returns 1 (does match)
 *
 * /  should not appear as it is considered the separator of the CID info.
 *    XXX at the moment we may stop on this char.
 *
 * X Z N match ranges 0-9, 1-9, 2-9 respectively.
 * [  denotes the start of a set of character. Everything inside
 *    is considered literally. We can have ranges a-d and individual
 *    characters. A '[' and '-' can be considered literally if they
 *    are just before ']'.
 *    XXX currently there is no way to specify ']' in a range, nor \ is
 *    considered specially.
 *
 * When we compare a pattern with a specific extension, all characters in the extension
 * itself are considered literally.
 * XXX do we want to consider space as a separator as well ?
 * XXX do we want to consider the separators in non-patterns as well ?
 */

/*!
 * \brief helper functions to sort extensions and patterns in the desired way,
 * so that more specific patterns appear first.
 *
 * ext_cmp1 compares individual characters (or sets of), returning
 * an int where bits 0-7 are the ASCII code of the first char in the set,
 * while bit 8-15 are the cardinality of the set minus 1.
 * This way more specific patterns (smaller cardinality) appear first.
 * Wildcards have a special value, so that we can directly compare them to
 * sets by subtracting the two values. In particular:
 *  0x000xx    one character, xx
 *  0x0yyxx    yy character set starting with xx
 *  0x10000    '.' (one or more of anything)
 *  0x20000    '!' (zero or more of anything)
 *  0x30000    NUL (end of string)
 *  0x40000    error in set.
 * The pointer to the string is advanced according to needs.
 * NOTES:
 * 1. the empty set is equivalent to NUL.
 * 2. given that a full set has always 0 as the first element,
 *    we could encode the special cases as 0xffXX where XX
 *    is 1, 2, 3, 4 as used above.
 */
static int ext_cmp1(const char **p, unsigned char *bitwise)
{
   int c, cmin = 0xff, count = 0;
   const char *end;

   /* load value and advance pointer */
   c = *(*p)++;

   /* always return unless we have a set of chars */
   switch (toupper(c)) {
   default: /* ordinary character */
      bitwise[c / 8] = 1 << (c % 8);
      return 0x0100 | (c & 0xff);

   case 'N':   /* 2..9 */
      bitwise[6] = 0xfc;
      bitwise[7] = 0x03;
      return 0x0800 | '2';

   case 'X':   /* 0..9 */
      bitwise[6] = 0xff;
      bitwise[7] = 0x03;
      return 0x0A00 | '0';

   case 'Z':   /* 1..9 */
      bitwise[6] = 0xfe;
      bitwise[7] = 0x03;
      return 0x0900 | '1';

   case '.':   /* wildcard */
      return 0x18000;

   case '!':   /* earlymatch */
      return 0x28000;   /* less specific than NULL */

   case '\0':  /* empty string */
      *p = NULL;
      return 0x30000;

   case '[':   /* pattern */
      break;
   }
   /* locate end of set */
   end = strchr(*p, ']');

   if (end == NULL) {
      ast_log(LOG_WARNING, "Wrong usage of [] in the extension\n");
      return 0x40000;   /* XXX make this entry go last... */
   }

   for (; *p < end  ; (*p)++) {
      unsigned char c1, c2;   /* first-last char in range */
      c1 = (unsigned char)((*p)[0]);
      if (*p + 2 < end && (*p)[1] == '-') { /* this is a range */
         c2 = (unsigned char)((*p)[2]);
         *p += 2;    /* skip a total of 3 chars */
      } else {        /* individual character */
         c2 = c1;
      }
      if (c1 < cmin) {
         cmin = c1;
      }
      for (; c1 <= c2; c1++) {
         unsigned char mask = 1 << (c1 % 8);
         /*!\note If two patterns score the same, the one with the lowest
          * ascii values will compare as coming first. */
         /* Flag the character as included (used) and count it. */
         if (!(bitwise[ c1 / 8 ] & mask)) {
            bitwise[ c1 / 8 ] |= mask;
            count += 0x100;
         }
      }
   }
   (*p)++;
   return count == 0 ? 0x30000 : (count | cmin);
}

/*!
 * \brief the full routine to compare extensions in rules.
 */
static int ext_cmp(const char *a, const char *b)
{
   /* make sure non-patterns come first.
    * If a is not a pattern, it either comes first or
    * we do a more complex pattern comparison.
    */
   int ret = 0;

   if (a[0] != '_')
      return (b[0] == '_') ? -1 : strcmp(a, b);

   /* Now we know a is a pattern; if b is not, a comes first */
   if (b[0] != '_')
      return 1;

   /* ok we need full pattern sorting routine.
    * skip past the underscores */
   ++a; ++b;
   do {
      unsigned char bitwise[2][32] = { { 0, } };
      ret = ext_cmp1(&a, bitwise[0]) - ext_cmp1(&b, bitwise[1]);
      if (ret == 0) {
         /* Are the classes different, even though they score the same? */
         ret = memcmp(bitwise[0], bitwise[1], 32);
      }
   } while (!ret && a && b);
   if (ret == 0) {
      return 0;
   } else {
      return (ret > 0) ? 1 : -1;
   }
}

int ast_extension_cmp(const char *a, const char *b)
{
   return ext_cmp(a, b);
}

/*!
 * \internal
 * \brief used ast_extension_{match|close}
 * mode is as follows:
 * E_MATCH     success only on exact match
 * E_MATCHMORE success only on partial match (i.e. leftover digits in pattern)
 * E_CANMATCH  either of the above.
 * \retval 0 on no-match
 * \retval 1 on match
 * \retval 2 on early match.
 */

static int _extension_match_core(const char *pattern, const char *data, enum ext_match_t mode)
{
   mode &= E_MATCH_MASK;   /* only consider the relevant bits */

#ifdef NEED_DEBUG_HERE
   ast_log(LOG_NOTICE,"match core: pat: '%s', dat: '%s', mode=%d\n", pattern, data, (int)mode);
#endif

   if ( (mode == E_MATCH) && (pattern[0] == '_') && (!strcasecmp(pattern,data)) ) { /* note: if this test is left out, then _x. will not match _x. !!! */
#ifdef NEED_DEBUG_HERE
      ast_log(LOG_NOTICE,"return (1) - pattern matches pattern\n");
#endif
      return 1;
   }

   if (pattern[0] != '_') { /* not a pattern, try exact or partial match */
      int ld = strlen(data), lp = strlen(pattern);

      if (lp < ld) {    /* pattern too short, cannot match */
#ifdef NEED_DEBUG_HERE
         ast_log(LOG_NOTICE,"return (0) - pattern too short, cannot match\n");
#endif
         return 0;
      }
      /* depending on the mode, accept full or partial match or both */
      if (mode == E_MATCH) {
#ifdef NEED_DEBUG_HERE
         ast_log(LOG_NOTICE,"return (!strcmp(%s,%s) when mode== E_MATCH)\n", pattern, data);
#endif
         return !strcmp(pattern, data); /* 1 on match, 0 on fail */
      }
      if (ld == 0 || !strncasecmp(pattern, data, ld)) { /* partial or full match */
#ifdef NEED_DEBUG_HERE
         ast_log(LOG_NOTICE,"return (mode(%d) == E_MATCHMORE ? lp(%d) > ld(%d) : 1)\n", mode, lp, ld);
#endif
         return (mode == E_MATCHMORE) ? lp > ld : 1; /* XXX should consider '!' and '/' ? */
      } else {
#ifdef NEED_DEBUG_HERE
         ast_log(LOG_NOTICE,"return (0) when ld(%d) > 0 && pattern(%s) != data(%s)\n", ld, pattern, data);
#endif
         return 0;
      }
   }
   pattern++; /* skip leading _ */
   /*
    * XXX below we stop at '/' which is a separator for the CID info. However we should
    * not store '/' in the pattern at all. When we insure it, we can remove the checks.
    */
   while (*data && *pattern && *pattern != '/') {
      const char *end;

      if (*data == '-') { /* skip '-' in data (just a separator) */
         data++;
         continue;
      }
      switch (toupper(*pattern)) {
      case '[':   /* a range */
         end = strchr(pattern+1, ']'); /* XXX should deal with escapes ? */
         if (end == NULL) {
            ast_log(LOG_WARNING, "Wrong usage of [] in the extension\n");
            return 0;   /* unconditional failure */
         }
         for (pattern++; pattern != end; pattern++) {
            if (pattern+2 < end && pattern[1] == '-') { /* this is a range */
               if (*data >= pattern[0] && *data <= pattern[2])
                  break;   /* match found */
               else {
                  pattern += 2; /* skip a total of 3 chars */
                  continue;
               }
            } else if (*data == pattern[0])
               break;   /* match found */
         }
         if (pattern == end) {
#ifdef NEED_DEBUG_HERE
            ast_log(LOG_NOTICE,"return (0) when pattern==end\n");
#endif
            return 0;
         }
         pattern = end; /* skip and continue */
         break;
      case 'N':
         if (*data < '2' || *data > '9') {
#ifdef NEED_DEBUG_HERE
            ast_log(LOG_NOTICE,"return (0) N is matched\n");
#endif
            return 0;
         }
         break;
      case 'X':
         if (*data < '0' || *data > '9') {
#ifdef NEED_DEBUG_HERE
            ast_log(LOG_NOTICE,"return (0) X is matched\n");
#endif
            return 0;
         }
         break;
      case 'Z':
         if (*data < '1' || *data > '9') {
#ifdef NEED_DEBUG_HERE
            ast_log(LOG_NOTICE,"return (0) Z is matched\n");
#endif
            return 0;
         }
         break;
      case '.':   /* Must match, even with more digits */
#ifdef NEED_DEBUG_HERE
         ast_log(LOG_NOTICE, "return (1) when '.' is matched\n");
#endif
         return 1;
      case '!':   /* Early match */
#ifdef NEED_DEBUG_HERE
         ast_log(LOG_NOTICE, "return (2) when '!' is matched\n");
#endif
         return 2;
      case ' ':
      case '-':   /* Ignore these in patterns */
         data--; /* compensate the final data++ */
         break;
      default:
         if (*data != *pattern) {
#ifdef NEED_DEBUG_HERE
            ast_log(LOG_NOTICE, "return (0) when *data(%c) != *pattern(%c)\n", *data, *pattern);
#endif
            return 0;
         }
      }
      data++;
      pattern++;
   }
   if (*data)        /* data longer than pattern, no match */ {
#ifdef NEED_DEBUG_HERE
      ast_log(LOG_NOTICE, "return (0) when data longer than pattern\n");
#endif
      return 0;
   }

   /*
    * match so far, but ran off the end of the data.
    * Depending on what is next, determine match or not.
    */
   if (*pattern == '\0' || *pattern == '/') {   /* exact match */
#ifdef NEED_DEBUG_HERE
      ast_log(LOG_NOTICE, "at end, return (%d) in 'exact match'\n", (mode==E_MATCHMORE) ? 0 : 1);
#endif
      return (mode == E_MATCHMORE) ? 0 : 1;  /* this is a failure for E_MATCHMORE */
   } else if (*pattern == '!')   {     /* early match */
#ifdef NEED_DEBUG_HERE
      ast_log(LOG_NOTICE, "at end, return (2) when '!' is matched\n");
#endif
      return 2;
   } else {                /* partial match */
#ifdef NEED_DEBUG_HERE
      ast_log(LOG_NOTICE, "at end, return (%d) which deps on E_MATCH\n", (mode == E_MATCH) ? 0 : 1);
#endif
      return (mode == E_MATCH) ? 0 : 1;   /* this is a failure for E_MATCH */
   }
}

/*
 * Wrapper around _extension_match_core() to do performance measurement
 * using the profiling code.
 */
static int extension_match_core(const char *pattern, const char *data, enum ext_match_t mode)
{
   int i;
   static int prof_id = -2;   /* marker for 'unallocated' id */
   if (prof_id == -2) {
      prof_id = ast_add_profile("ext_match", 0);
   }
   ast_mark(prof_id, 1);
   i = _extension_match_core(ast_strlen_zero(pattern) ? "" : pattern, ast_strlen_zero(data) ? "" : data, mode);
   ast_mark(prof_id, 0);
   return i;
}

int ast_extension_match(const char *pattern, const char *data)
{
   return extension_match_core(pattern, data, E_MATCH);
}

int ast_extension_close(const char *pattern, const char *data, int needmore)
{
   if (needmore != E_MATCHMORE && needmore != E_CANMATCH)
      ast_log(LOG_WARNING, "invalid argument %d\n", needmore);
   return extension_match_core(pattern, data, needmore);
}

struct fake_context /* this struct is purely for matching in the hashtab */
{
   ast_rwlock_t lock;
   struct ast_exten *root;
   struct ast_hashtab *root_table;
   struct match_char *pattern_tree;
   struct ast_context *next;
   struct ast_include *includes;
   struct ast_ignorepat *ignorepats;
   const char *registrar;
   int refcount;
   AST_LIST_HEAD_NOLOCK(, ast_sw) alts;
   ast_mutex_t macrolock;
   char name[256];
};

struct ast_context *ast_context_find(const char *name)
{
   struct ast_context *tmp;
   struct fake_context item;

   if (!name) {
      return NULL;
   }
   ast_rdlock_contexts();
   if (contexts_table) {
      ast_copy_string(item.name, name, sizeof(item.name));
      tmp = ast_hashtab_lookup(contexts_table, &item);
   } else {
      tmp = NULL;
      while ((tmp = ast_walk_contexts(tmp))) {
         if (!strcasecmp(name, tmp->name)) {
            break;
         }
      }
   }
   ast_unlock_contexts();
   return tmp;
}

#define STATUS_NO_CONTEXT  1
#define STATUS_NO_EXTENSION   2
#define STATUS_NO_PRIORITY 3
#define STATUS_NO_LABEL    4
#define STATUS_SUCCESS     5

static int matchcid(const char *cidpattern, const char *callerid)
{
   /* If the Caller*ID pattern is empty, then we're matching NO Caller*ID, so
      failing to get a number should count as a match, otherwise not */

   if (ast_strlen_zero(callerid)) {
      return ast_strlen_zero(cidpattern) ? 1 : 0;
   }

   return ast_extension_match(cidpattern, callerid);
}

struct ast_exten *pbx_find_extension(struct ast_channel *chan,
   struct ast_context *bypass, struct pbx_find_info *q,
   const char *context, const char *exten, int priority,
   const char *label, const char *callerid, enum ext_match_t action)
{
   int x, res;
   struct ast_context *tmp = NULL;
   struct ast_exten *e = NULL, *eroot = NULL;
   struct ast_include *i = NULL;
   struct ast_sw *sw = NULL;
   struct ast_exten pattern = {NULL, };
   struct scoreboard score = {0, };
   struct ast_str *tmpdata = NULL;

   pattern.label = label;
   pattern.priority = priority;
#ifdef NEED_DEBUG_HERE
   ast_log(LOG_NOTICE, "Looking for cont/ext/prio/label/action = %s/%s/%d/%s/%d\n", context, exten, priority, label, (int) action);
#endif

   /* Initialize status if appropriate */
   if (q->stacklen == 0) {
      q->status = STATUS_NO_CONTEXT;
      q->swo = NULL;
      q->data = NULL;
      q->foundcontext = NULL;
   } else if (q->stacklen >= AST_PBX_MAX_STACK) {
      ast_log(LOG_WARNING, "Maximum PBX stack exceeded\n");
      return NULL;
   }

   /* Check first to see if we've already been checked */
   for (x = 0; x < q->stacklen; x++) {
      if (!strcasecmp(q->incstack[x], context))
         return NULL;
   }

   if (bypass) { /* bypass means we only look there */
      tmp = bypass;
   } else {      /* look in contexts */
      tmp = find_context(context);
      if (!tmp) {
         return NULL;
      }
   }

   if (q->status < STATUS_NO_EXTENSION)
      q->status = STATUS_NO_EXTENSION;

   /* Do a search for matching extension */

   eroot = NULL;
   score.total_specificity = 0;
   score.exten = 0;
   score.total_length = 0;
   if (!tmp->pattern_tree && tmp->root_table) {
      create_match_char_tree(tmp);
#ifdef NEED_DEBUG
      ast_debug(1, "Tree Created in context %s:\n", context);
      log_match_char_tree(tmp->pattern_tree," ");
#endif
   }
#ifdef NEED_DEBUG
   ast_log(LOG_NOTICE, "The Trie we are searching in:\n");
   log_match_char_tree(tmp->pattern_tree, "::  ");
#endif

   do {
      if (!ast_strlen_zero(overrideswitch)) {
         char *osw = ast_strdupa(overrideswitch), *name;
         struct ast_switch *asw;
         ast_switch_f *aswf = NULL;
         char *datap;
         int eval = 0;

         name = strsep(&osw, "/");
         asw = pbx_findswitch(name);

         if (!asw) {
            ast_log(LOG_WARNING, "No such switch '%s'\n", name);
            break;
         }

         if (osw && strchr(osw, '$')) {
            eval = 1;
         }

         if (eval && !(tmpdata = ast_str_thread_get(&switch_data, 512))) {
            ast_log(LOG_WARNING, "Can't evaluate overrideswitch?!\n");
            break;
         } else if (eval) {
            /* Substitute variables now */
            pbx_substitute_variables_helper(chan, osw, ast_str_buffer(tmpdata), ast_str_size(tmpdata));
            datap = ast_str_buffer(tmpdata);
         } else {
            datap = osw;
         }

         /* equivalent of extension_match_core() at the switch level */
         if (action == E_CANMATCH)
            aswf = asw->canmatch;
         else if (action == E_MATCHMORE)
            aswf = asw->matchmore;
         else /* action == E_MATCH */
            aswf = asw->exists;
         if (!aswf) {
            res = 0;
         } else {
            if (chan) {
               ast_autoservice_start(chan);
            }
            res = aswf(chan, context, exten, priority, callerid, datap);
            if (chan) {
               ast_autoservice_stop(chan);
            }
         }
         if (res) {  /* Got a match */
            q->swo = asw;
            q->data = datap;
            q->foundcontext = context;
            /* XXX keep status = STATUS_NO_CONTEXT ? */
            return NULL;
         }
      }
   } while (0);

   if (extenpatternmatchnew) {
      new_find_extension(exten, &score, tmp->pattern_tree, 0, 0, callerid, label, action);
      eroot = score.exten;

      if (score.last_char == '!' && action == E_MATCHMORE) {
         /* We match an extension ending in '!'.
          * The decision in this case is final and is NULL (no match).
          */
#ifdef NEED_DEBUG_HERE
         ast_log(LOG_NOTICE,"Returning MATCHMORE NULL with exclamation point.\n");
#endif
         return NULL;
      }

      if (!eroot && (action == E_CANMATCH || action == E_MATCHMORE) && score.canmatch_exten) {
         q->status = STATUS_SUCCESS;
#ifdef NEED_DEBUG_HERE
         ast_log(LOG_NOTICE,"Returning CANMATCH exten %s\n", score.canmatch_exten->exten);
#endif
         return score.canmatch_exten;
      }

      if ((action == E_MATCHMORE || action == E_CANMATCH)  && eroot) {
         if (score.node) {
            struct ast_exten *z = trie_find_next_match(score.node);
            if (z) {
#ifdef NEED_DEBUG_HERE
               ast_log(LOG_NOTICE,"Returning CANMATCH/MATCHMORE next_match exten %s\n", z->exten);
#endif
            } else {
               if (score.canmatch_exten) {
#ifdef NEED_DEBUG_HERE
                  ast_log(LOG_NOTICE,"Returning CANMATCH/MATCHMORE canmatchmatch exten %s(%p)\n", score.canmatch_exten->exten, score.canmatch_exten);
#endif
                  return score.canmatch_exten;
               } else {
#ifdef NEED_DEBUG_HERE
                  ast_log(LOG_NOTICE,"Returning CANMATCH/MATCHMORE next_match exten NULL\n");
#endif
               }
            }
            return z;
         }
#ifdef NEED_DEBUG_HERE
         ast_log(LOG_NOTICE, "Returning CANMATCH/MATCHMORE NULL (no next_match)\n");
#endif
         return NULL;  /* according to the code, complete matches are null matches in MATCHMORE mode */
      }

      if (eroot) {
         /* found entry, now look for the right priority */
         if (q->status < STATUS_NO_PRIORITY)
            q->status = STATUS_NO_PRIORITY;
         e = NULL;
         if (action == E_FINDLABEL && label ) {
            if (q->status < STATUS_NO_LABEL)
               q->status = STATUS_NO_LABEL;
            e = ast_hashtab_lookup(eroot->peer_label_table, &pattern);
         } else {
            e = ast_hashtab_lookup(eroot->peer_table, &pattern);
         }
         if (e) { /* found a valid match */
            q->status = STATUS_SUCCESS;
            q->foundcontext = context;
#ifdef NEED_DEBUG_HERE
            ast_log(LOG_NOTICE,"Returning complete match of exten %s\n", e->exten);
#endif
            return e;
         }
      }
   } else {   /* the old/current default exten pattern match algorithm */

      /* scan the list trying to match extension and CID */
      eroot = NULL;
      while ( (eroot = ast_walk_context_extensions(tmp, eroot)) ) {
         int match = extension_match_core(eroot->exten, exten, action);
         /* 0 on fail, 1 on match, 2 on earlymatch */

         if (!match || (eroot->matchcid && !matchcid(eroot->cidmatch, callerid)))
            continue;   /* keep trying */
         if (match == 2 && action == E_MATCHMORE) {
            /* We match an extension ending in '!'.
             * The decision in this case is final and is NULL (no match).
             */
            return NULL;
         }
         /* found entry, now look for the right priority */
         if (q->status < STATUS_NO_PRIORITY)
            q->status = STATUS_NO_PRIORITY;
         e = NULL;
         if (action == E_FINDLABEL && label ) {
            if (q->status < STATUS_NO_LABEL)
               q->status = STATUS_NO_LABEL;
            e = ast_hashtab_lookup(eroot->peer_label_table, &pattern);
         } else {
            e = ast_hashtab_lookup(eroot->peer_table, &pattern);
         }
         if (e) { /* found a valid match */
            q->status = STATUS_SUCCESS;
            q->foundcontext = context;
            return e;
         }
      }
   }

   /* Check alternative switches */
   AST_LIST_TRAVERSE(&tmp->alts, sw, list) {
      struct ast_switch *asw = pbx_findswitch(sw->name);
      ast_switch_f *aswf = NULL;
      char *datap;

      if (!asw) {
         ast_log(LOG_WARNING, "No such switch '%s'\n", sw->name);
         continue;
      }

      /* Substitute variables now */
      if (sw->eval) {
         if (!(tmpdata = ast_str_thread_get(&switch_data, 512))) {
            ast_log(LOG_WARNING, "Can't evaluate switch?!\n");
            continue;
         }
         pbx_substitute_variables_helper(chan, sw->data, ast_str_buffer(tmpdata), ast_str_size(tmpdata));
      }

      /* equivalent of extension_match_core() at the switch level */
      if (action == E_CANMATCH)
         aswf = asw->canmatch;
      else if (action == E_MATCHMORE)
         aswf = asw->matchmore;
      else /* action == E_MATCH */
         aswf = asw->exists;
      datap = sw->eval ? ast_str_buffer(tmpdata) : sw->data;
      if (!aswf)
         res = 0;
      else {
         if (chan)
            ast_autoservice_start(chan);
         res = aswf(chan, context, exten, priority, callerid, datap);
         if (chan)
            ast_autoservice_stop(chan);
      }
      if (res) {  /* Got a match */
         q->swo = asw;
         q->data = datap;
         q->foundcontext = context;
         /* XXX keep status = STATUS_NO_CONTEXT ? */
         return NULL;
      }
   }
   q->incstack[q->stacklen++] = tmp->name;   /* Setup the stack */
   /* Now try any includes we have in this context */
   for (i = tmp->includes; i; i = i->next) {
      if (include_valid(i)) {
         if ((e = pbx_find_extension(chan, bypass, q, i->rname, exten, priority, label, callerid, action))) {
#ifdef NEED_DEBUG_HERE
            ast_log(LOG_NOTICE,"Returning recursive match of %s\n", e->exten);
#endif
            return e;
         }
         if (q->swo)
            return NULL;
      }
   }
   return NULL;
}

/*!
 * \brief extract offset:length from variable name.
 * \return 1 if there is a offset:length part, which is
 * trimmed off (values go into variables)
 */
static int parse_variable_name(char *var, int *offset, int *length, int *isfunc)
{
   int parens = 0;

   *offset = 0;
   *length = INT_MAX;
   *isfunc = 0;
   for (; *var; var++) {
      if (*var == '(') {
         (*isfunc)++;
         parens++;
      } else if (*var == ')') {
         parens--;
      } else if (*var == ':' && parens == 0) {
         *var++ = '\0';
         sscanf(var, "%30d:%30d", offset, length);
         return 1; /* offset:length valid */
      }
   }
   return 0;
}

/*!
 *\brief takes a substring. It is ok to call with value == workspace.
 * \param value
 * \param offset < 0 means start from the end of the string and set the beginning
 *   to be that many characters back.
 * \param length is the length of the substring, a value less than 0 means to leave
 * that many off the end.
 * \param workspace
 * \param workspace_len
 * Always return a copy in workspace.
 */
static char *substring(const char *value, int offset, int length, char *workspace, size_t workspace_len)
{
   char *ret = workspace;
   int lr;  /* length of the input string after the copy */

   ast_copy_string(workspace, value, workspace_len); /* always make a copy */

   lr = strlen(ret); /* compute length after copy, so we never go out of the workspace */

   /* Quick check if no need to do anything */
   if (offset == 0 && length >= lr) /* take the whole string */
      return ret;

   if (offset < 0)   {  /* translate negative offset into positive ones */
      offset = lr + offset;
      if (offset < 0) /* If the negative offset was greater than the length of the string, just start at the beginning */
         offset = 0;
   }

   /* too large offset result in empty string so we know what to return */
   if (offset >= lr)
      return ret + lr;  /* the final '\0' */

   ret += offset;    /* move to the start position */
   if (length >= 0 && length < lr - offset)  /* truncate if necessary */
      ret[length] = '\0';
   else if (length < 0) {
      if (lr > offset - length) /* After we remove from the front and from the rear, is there anything left? */
         ret[lr + length - offset] = '\0';
      else
         ret[0] = '\0';
   }

   return ret;
}

static const char *ast_str_substring(struct ast_str *value, int offset, int length)
{
   int lr;  /* length of the input string after the copy */

   lr = ast_str_strlen(value); /* compute length after copy, so we never go out of the workspace */

   /* Quick check if no need to do anything */
   if (offset == 0 && length >= lr) /* take the whole string */
      return ast_str_buffer(value);

   if (offset < 0)   {  /* translate negative offset into positive ones */
      offset = lr + offset;
      if (offset < 0) /* If the negative offset was greater than the length of the string, just start at the beginning */
         offset = 0;
   }

   /* too large offset result in empty string so we know what to return */
   if (offset >= lr) {
      ast_str_reset(value);
      return ast_str_buffer(value);
   }

   if (offset > 0) {
      /* Go ahead and chop off the beginning */
      memmove(ast_str_buffer(value), ast_str_buffer(value) + offset, ast_str_strlen(value) - offset + 1);
      lr -= offset;
   }

   if (length >= 0 && length < lr) {   /* truncate if necessary */
      char *tmp = ast_str_buffer(value);
      tmp[length] = '\0';
      ast_str_update(value);
   } else if (length < 0) {
      if (lr > -length) { /* After we remove from the front and from the rear, is there anything left? */
         char *tmp = ast_str_buffer(value);
         tmp[lr + length] = '\0';
         ast_str_update(value);
      } else {
         ast_str_reset(value);
      }
   } else {
      /* Nothing to do, but update the buffer length */
      ast_str_update(value);
   }

   return ast_str_buffer(value);
}

/*! \brief  Support for Asterisk built-in variables in the dialplan

\note See also
   - \ref AstVar  Channel variables
   - \ref AstCauses The HANGUPCAUSE variable
 */
void pbx_retrieve_variable(struct ast_channel *c, const char *var, char **ret, char *workspace, int workspacelen, struct varshead *headp)
{
   struct ast_str *str = ast_str_create(16);
   const char *cret;

   cret = ast_str_retrieve_variable(&str, 0, c, headp, var);
   ast_copy_string(workspace, ast_str_buffer(str), workspacelen);
   *ret = cret ? workspace : NULL;
   ast_free(str);
}

const char *ast_str_retrieve_variable(struct ast_str **str, ssize_t maxlen, struct ast_channel *c, struct varshead *headp, const char *var)
{
   const char not_found = '\0';
   char *tmpvar;
   const char *ret;
   const char *s; /* the result */
   int offset, length;
   int i, need_substring;
   struct varshead *places[2] = { headp, &globals };  /* list of places where we may look */
   char workspace[20];

   if (c) {
      ast_channel_lock(c);
      places[0] = ast_channel_varshead(c);
   }
   /*
    * Make a copy of var because parse_variable_name() modifies the string.
    * Then if called directly, we might need to run substring() on the result;
    * remember this for later in 'need_substring', 'offset' and 'length'
    */
   tmpvar = ast_strdupa(var); /* parse_variable_name modifies the string */
   need_substring = parse_variable_name(tmpvar, &offset, &length, &i /* ignored */);

   /*
    * Look first into predefined variables, then into variable lists.
    * Variable 's' points to the result, according to the following rules:
    * s == &not_found (set at the beginning) means that we did not find a
    * matching variable and need to look into more places.
    * If s != &not_found, s is a valid result string as follows:
    * s = NULL if the variable does not have a value;
    * you typically do this when looking for an unset predefined variable.
    * s = workspace if the result has been assembled there;
    * typically done when the result is built e.g. with an snprintf(),
    * so we don't need to do an additional copy.
    * s != workspace in case we have a string, that needs to be copied
    * (the ast_copy_string is done once for all at the end).
    * Typically done when the result is already available in some string.
    */
   s = &not_found;   /* default value */
   if (c) { /* This group requires a valid channel */
      /* Names with common parts are looked up a piece at a time using strncmp. */
      if (!strncmp(var, "CALL", 4)) {
         if (!strncmp(var + 4, "ING", 3)) {
            if (!strcmp(var + 7, "PRES")) {        /* CALLINGPRES */
               ast_str_set(str, maxlen, "%d",
                  ast_party_id_presentation(&ast_channel_caller(c)->id));
               s = ast_str_buffer(*str);
            } else if (!strcmp(var + 7, "ANI2")) {    /* CALLINGANI2 */
               ast_str_set(str, maxlen, "%d", ast_channel_caller(c)->ani2);
               s = ast_str_buffer(*str);
            } else if (!strcmp(var + 7, "TON")) {     /* CALLINGTON */
               ast_str_set(str, maxlen, "%d", ast_channel_caller(c)->id.number.plan);
               s = ast_str_buffer(*str);
            } else if (!strcmp(var + 7, "TNS")) {     /* CALLINGTNS */
               ast_str_set(str, maxlen, "%d", ast_channel_dialed(c)->transit_network_select);
               s = ast_str_buffer(*str);
            }
         }
      } else if (!strcmp(var, "HINT")) {
         s = ast_str_get_hint(str, maxlen, NULL, 0, c, ast_channel_context(c), ast_channel_exten(c)) ? ast_str_buffer(*str) : NULL;
      } else if (!strcmp(var, "HINTNAME")) {
         s = ast_str_get_hint(NULL, 0, str, maxlen, c, ast_channel_context(c), ast_channel_exten(c)) ? ast_str_buffer(*str) : NULL;
      } else if (!strcmp(var, "EXTEN")) {
         s = ast_channel_exten(c);
      } else if (!strcmp(var, "CONTEXT")) {
         s = ast_channel_context(c);
      } else if (!strcmp(var, "PRIORITY")) {
         ast_str_set(str, maxlen, "%d", ast_channel_priority(c));
         s = ast_str_buffer(*str);
      } else if (!strcmp(var, "CHANNEL")) {
         s = ast_channel_name(c);
      } else if (!strcmp(var, "UNIQUEID")) {
         s = ast_channel_uniqueid(c);
      } else if (!strcmp(var, "HANGUPCAUSE")) {
         ast_str_set(str, maxlen, "%d", ast_channel_hangupcause(c));
         s = ast_str_buffer(*str);
      }
   }
   if (s == &not_found) { /* look for more */
      if (!strcmp(var, "EPOCH")) {
         ast_str_set(str, maxlen, "%u", (int) time(NULL));
         s = ast_str_buffer(*str);
      } else if (!strcmp(var, "SYSTEMNAME")) {
         s = ast_config_AST_SYSTEM_NAME;
      } else if (!strcmp(var, "ASTETCDIR")) {
         s = ast_config_AST_CONFIG_DIR;
      } else if (!strcmp(var, "ASTMODDIR")) {
         s = ast_config_AST_MODULE_DIR;
      } else if (!strcmp(var, "ASTVARLIBDIR")) {
         s = ast_config_AST_VAR_DIR;
      } else if (!strcmp(var, "ASTDBDIR")) {
         s = ast_config_AST_DB;
      } else if (!strcmp(var, "ASTKEYDIR")) {
         s = ast_config_AST_KEY_DIR;
      } else if (!strcmp(var, "ASTDATADIR")) {
         s = ast_config_AST_DATA_DIR;
      } else if (!strcmp(var, "ASTAGIDIR")) {
         s = ast_config_AST_AGI_DIR;
      } else if (!strcmp(var, "ASTSPOOLDIR")) {
         s = ast_config_AST_SPOOL_DIR;
      } else if (!strcmp(var, "ASTRUNDIR")) {
         s = ast_config_AST_RUN_DIR;
      } else if (!strcmp(var, "ASTLOGDIR")) {
         s = ast_config_AST_LOG_DIR;
      } else if (!strcmp(var, "ENTITYID")) {
         ast_eid_to_str(workspace, sizeof(workspace), &ast_eid_default);
         s = workspace;
      }
   }
   /* if not found, look into chanvars or global vars */
   for (i = 0; s == &not_found && i < ARRAY_LEN(places); i++) {
      struct ast_var_t *variables;
      if (!places[i])
         continue;
      if (places[i] == &globals)
         ast_rwlock_rdlock(&globalslock);
      AST_LIST_TRAVERSE(places[i], variables, entries) {
         if (!strcasecmp(ast_var_name(variables), var)) {
            s = ast_var_value(variables);
            break;
         }
      }
      if (places[i] == &globals)
         ast_rwlock_unlock(&globalslock);
   }
   if (s == &not_found || s == NULL) {
      ast_debug(5, "Result of '%s' is NULL\n", var);
      ret = NULL;
   } else {
      ast_debug(5, "Result of '%s' is '%s'\n", var, s);
      if (s != ast_str_buffer(*str)) {
         ast_str_set(str, maxlen, "%s", s);
      }
      ret = ast_str_buffer(*str);
      if (need_substring) {
         ret = ast_str_substring(*str, offset, length);
         ast_debug(2, "Final result of '%s' is '%s'\n", var, ret);
      }
   }

   if (c) {
      ast_channel_unlock(c);
   }
   return ret;
}

static void exception_store_free(void *data)
{
   struct pbx_exception *exception = data;
   ast_string_field_free_memory(exception);
   ast_free(exception);
}

static const struct ast_datastore_info exception_store_info = {
   .type = "EXCEPTION",
   .destroy = exception_store_free,
};

/*!
 * \internal
 * \brief Set the PBX to execute the exception extension.
 *
 * \param chan Channel to raise the exception on.
 * \param reason Reason exception is raised.
 * \param priority Dialplan priority to set.
 *
 * \retval 0 on success.
 * \retval -1 on error.
 */
static int raise_exception(struct ast_channel *chan, const char *reason, int priority)
{
   struct ast_datastore *ds = ast_channel_datastore_find(chan, &exception_store_info, NULL);
   struct pbx_exception *exception = NULL;

   if (!ds) {
      ds = ast_datastore_alloc(&exception_store_info, NULL);
      if (!ds)
         return -1;
      if (!(exception = ast_calloc_with_stringfields(1, struct pbx_exception, 128))) {
         ast_datastore_free(ds);
         return -1;
      }
      ds->data = exception;
      ast_channel_datastore_add(chan, ds);
   } else
      exception = ds->data;

   ast_string_field_set(exception, reason, reason);
   ast_string_field_set(exception, context, ast_channel_context(chan));
   ast_string_field_set(exception, exten, ast_channel_exten(chan));
   exception->priority = ast_channel_priority(chan);
   set_ext_pri(chan, "e", priority);
   return 0;
}

int pbx_builtin_raise_exception(struct ast_channel *chan, const char *reason)
{
   /* Priority will become 1, next time through the AUTOLOOP */
   return raise_exception(chan, reason, 0);
}

static int acf_exception_read(struct ast_channel *chan, const char *name, char *data, char *buf, size_t buflen)
{
   struct ast_datastore *ds = ast_channel_datastore_find(chan, &exception_store_info, NULL);
   struct pbx_exception *exception = NULL;
   if (!ds || !ds->data)
      return -1;
   exception = ds->data;
   if (!strcasecmp(data, "REASON"))
      ast_copy_string(buf, exception->reason, buflen);
   else if (!strcasecmp(data, "CONTEXT"))
      ast_copy_string(buf, exception->context, buflen);
   else if (!strncasecmp(data, "EXTEN", 5))
      ast_copy_string(buf, exception->exten, buflen);
   else if (!strcasecmp(data, "PRIORITY"))
      snprintf(buf, buflen, "%d", exception->priority);
   else
      return -1;
   return 0;
}

static struct ast_custom_function exception_function = {
   .name = "EXCEPTION",
   .read = acf_exception_read,
};

static char *handle_show_functions(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct ast_custom_function *acf;
   int count_acf = 0;
   int like = 0;

   switch (cmd) {
   case CLI_INIT:
      e->command = "core show functions [like]";
      e->usage =
         "Usage: core show functions [like <text>]\n"
         "       List builtin functions, optionally only those matching a given string\n";
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   if (a->argc == 5 && (!strcmp(a->argv[3], "like")) ) {
      like = 1;
   } else if (a->argc != 3) {
      return CLI_SHOWUSAGE;
   }

   ast_cli(a->fd, "%s Custom Functions:\n--------------------------------------------------------------------------------\n", like ? "Matching" : "Installed");

   AST_RWLIST_RDLOCK(&acf_root);
   AST_RWLIST_TRAVERSE(&acf_root, acf, acflist) {
      if (!like || strstr(acf->name, a->argv[4])) {
         count_acf++;
         ast_cli(a->fd, "%-20.20s  %-35.35s  %s\n",
            S_OR(acf->name, ""),
            S_OR(acf->syntax, ""),
            S_OR(acf->synopsis, ""));
      }
   }
   AST_RWLIST_UNLOCK(&acf_root);

   ast_cli(a->fd, "%d %scustom functions installed.\n", count_acf, like ? "matching " : "");

   return CLI_SUCCESS;
}

static char *handle_show_function(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct ast_custom_function *acf;
   /* Maximum number of characters added by terminal coloring is 22 */
   char infotitle[64 + AST_MAX_APP + 22], syntitle[40], destitle[40], argtitle[40], seealsotitle[40];
   char info[64 + AST_MAX_APP], *synopsis = NULL, *description = NULL, *seealso = NULL;
   char stxtitle[40], *syntax = NULL, *arguments = NULL;
   int syntax_size, description_size, synopsis_size, arguments_size, seealso_size;
   char *ret = NULL;
   int which = 0;
   int wordlen;

   switch (cmd) {
   case CLI_INIT:
      e->command = "core show function";
      e->usage =
         "Usage: core show function <function>\n"
         "       Describe a particular dialplan function.\n";
      return NULL;
   case CLI_GENERATE:
      wordlen = strlen(a->word);
      /* case-insensitive for convenience in this 'complete' function */
      AST_RWLIST_RDLOCK(&acf_root);
      AST_RWLIST_TRAVERSE(&acf_root, acf, acflist) {
         if (!strncasecmp(a->word, acf->name, wordlen) && ++which > a->n) {
            ret = ast_strdup(acf->name);
            break;
         }
      }
      AST_RWLIST_UNLOCK(&acf_root);

      return ret;
   }

   if (a->argc < 4) {
      return CLI_SHOWUSAGE;
   }

   if (!(acf = ast_custom_function_find(a->argv[3]))) {
      ast_cli(a->fd, "No function by that name registered.\n");
      return CLI_FAILURE;
   }

   syntax_size = strlen(S_OR(acf->syntax, "Not Available")) + AST_TERM_MAX_ESCAPE_CHARS;
   if (!(syntax = ast_malloc(syntax_size))) {
      ast_cli(a->fd, "Memory allocation failure!\n");
      return CLI_FAILURE;
   }

   snprintf(info, sizeof(info), "\n  -= Info about function '%s' =- \n\n", acf->name);
   term_color(infotitle, info, COLOR_MAGENTA, 0, sizeof(infotitle));
   term_color(syntitle, "[Synopsis]\n", COLOR_MAGENTA, 0, 40);
   term_color(destitle, "[Description]\n", COLOR_MAGENTA, 0, 40);
   term_color(stxtitle, "[Syntax]\n", COLOR_MAGENTA, 0, 40);
   term_color(argtitle, "[Arguments]\n", COLOR_MAGENTA, 0, 40);
   term_color(seealsotitle, "[See Also]\n", COLOR_MAGENTA, 0, 40);
   term_color(syntax, S_OR(acf->syntax, "Not available"), COLOR_CYAN, 0, syntax_size);
#ifdef AST_XML_DOCS
   if (acf->docsrc == AST_XML_DOC) {
      arguments = ast_xmldoc_printable(S_OR(acf->arguments, "Not available"), 1);
      synopsis = ast_xmldoc_printable(S_OR(acf->synopsis, "Not available"), 1);
      description = ast_xmldoc_printable(S_OR(acf->desc, "Not available"), 1);
      seealso = ast_xmldoc_printable(S_OR(acf->seealso, "Not available"), 1);
   } else
#endif
   {
      synopsis_size = strlen(S_OR(acf->synopsis, "Not Available")) + AST_TERM_MAX_ESCAPE_CHARS;
      synopsis = ast_malloc(synopsis_size);

      description_size = strlen(S_OR(acf->desc, "Not Available")) + AST_TERM_MAX_ESCAPE_CHARS;
      description = ast_malloc(description_size);

      arguments_size = strlen(S_OR(acf->arguments, "Not Available")) + AST_TERM_MAX_ESCAPE_CHARS;
      arguments = ast_malloc(arguments_size);

      seealso_size = strlen(S_OR(acf->seealso, "Not Available")) + AST_TERM_MAX_ESCAPE_CHARS;
      seealso = ast_malloc(seealso_size);

      /* check allocated memory. */
      if (!synopsis || !description || !arguments || !seealso) {
         ast_free(synopsis);
         ast_free(description);
         ast_free(arguments);
         ast_free(seealso);
         ast_free(syntax);
         return CLI_FAILURE;
      }

      term_color(arguments, S_OR(acf->arguments, "Not available"), COLOR_CYAN, 0, arguments_size);
      term_color(synopsis, S_OR(acf->synopsis, "Not available"), COLOR_CYAN, 0, synopsis_size);
      term_color(description, S_OR(acf->desc, "Not available"), COLOR_CYAN, 0, description_size);
      term_color(seealso, S_OR(acf->seealso, "Not available"), COLOR_CYAN, 0, seealso_size);
   }

   ast_cli(a->fd, "%s%s%s\n\n%s%s\n\n%s%s\n\n%s%s\n\n%s%s\n",
         infotitle, syntitle, synopsis, destitle, description,
         stxtitle, syntax, argtitle, arguments, seealsotitle, seealso);

   ast_free(arguments);
   ast_free(synopsis);
   ast_free(description);
   ast_free(seealso);
   ast_free(syntax);

   return CLI_SUCCESS;
}

struct ast_custom_function *ast_custom_function_find(const char *name)
{
   struct ast_custom_function *acf = NULL;

   AST_RWLIST_RDLOCK(&acf_root);
   AST_RWLIST_TRAVERSE(&acf_root, acf, acflist) {
      if (!strcmp(name, acf->name))
         break;
   }
   AST_RWLIST_UNLOCK(&acf_root);

   return acf;
}

int ast_custom_function_unregister(struct ast_custom_function *acf)
{
   struct ast_custom_function *cur;

   if (!acf) {
      return -1;
   }

   AST_RWLIST_WRLOCK(&acf_root);
   if ((cur = AST_RWLIST_REMOVE(&acf_root, acf, acflist))) {
#ifdef AST_XML_DOCS
      if (cur->docsrc == AST_XML_DOC) {
         ast_string_field_free_memory(acf);
      }
#endif
      ast_verb(2, "Unregistered custom function %s\n", cur->name);
   }
   AST_RWLIST_UNLOCK(&acf_root);

   return cur ? 0 : -1;
}

/*! \internal
 *  \brief Retrieve the XML documentation of a specified ast_custom_function,
 *         and populate ast_custom_function string fields.
 *  \param acf ast_custom_function structure with empty 'desc' and 'synopsis'
 *             but with a function 'name'.
 *  \retval -1 On error.
 *  \retval 0 On succes.
 */
static int acf_retrieve_docs(struct ast_custom_function *acf)
{
#ifdef AST_XML_DOCS
   char *tmpxml;

   /* Let's try to find it in the Documentation XML */
   if (!ast_strlen_zero(acf->desc) || !ast_strlen_zero(acf->synopsis)) {
      return 0;
   }

   if (ast_string_field_init(acf, 128)) {
      return -1;
   }

   /* load synopsis */
   tmpxml = ast_xmldoc_build_synopsis("function", acf->name, ast_module_name(acf->mod));
   ast_string_field_set(acf, synopsis, tmpxml);
   ast_free(tmpxml);

   /* load description */
   tmpxml = ast_xmldoc_build_description("function", acf->name, ast_module_name(acf->mod));
   ast_string_field_set(acf, desc, tmpxml);
   ast_free(tmpxml);

   /* load syntax */
   tmpxml = ast_xmldoc_build_syntax("function", acf->name, ast_module_name(acf->mod));
   ast_string_field_set(acf, syntax, tmpxml);
   ast_free(tmpxml);

   /* load arguments */
   tmpxml = ast_xmldoc_build_arguments("function", acf->name, ast_module_name(acf->mod));
   ast_string_field_set(acf, arguments, tmpxml);
   ast_free(tmpxml);

   /* load seealso */
   tmpxml = ast_xmldoc_build_seealso("function", acf->name, ast_module_name(acf->mod));
   ast_string_field_set(acf, seealso, tmpxml);
   ast_free(tmpxml);

   acf->docsrc = AST_XML_DOC;
#endif

   return 0;
}

int __ast_custom_function_register(struct ast_custom_function *acf, struct ast_module *mod)
{
   struct ast_custom_function *cur;
   char tmps[80];

   if (!acf) {
      return -1;
   }

   acf->mod = mod;
#ifdef AST_XML_DOCS
   acf->docsrc = AST_STATIC_DOC;
#endif

   if (acf_retrieve_docs(acf)) {
      return -1;
   }

   AST_RWLIST_WRLOCK(&acf_root);

   AST_RWLIST_TRAVERSE(&acf_root, cur, acflist) {
      if (!strcmp(acf->name, cur->name)) {
         ast_log(LOG_ERROR, "Function %s already registered.\n", acf->name);
         AST_RWLIST_UNLOCK(&acf_root);
         return -1;
      }
   }

   /* Store in alphabetical order */
   AST_RWLIST_TRAVERSE_SAFE_BEGIN(&acf_root, cur, acflist) {
      if (strcasecmp(acf->name, cur->name) < 0) {
         AST_RWLIST_INSERT_BEFORE_CURRENT(acf, acflist);
         break;
      }
   }
   AST_RWLIST_TRAVERSE_SAFE_END;

   if (!cur) {
      AST_RWLIST_INSERT_TAIL(&acf_root, acf, acflist);
   }

   AST_RWLIST_UNLOCK(&acf_root);

   ast_verb(2, "Registered custom function '%s'\n", term_color(tmps, acf->name, COLOR_BRCYAN, 0, sizeof(tmps)));

   return 0;
}

/*! \brief return a pointer to the arguments of the function,
 * and terminates the function name with '\\0'
 */
static char *func_args(char *function)
{
   char *args = strchr(function, '(');

   if (!args) {
      ast_log(LOG_WARNING, "Function '%s' doesn't contain parentheses.  Assuming null argument.\n", function);
   } else {
      char *p;
      *args++ = '\0';
      if ((p = strrchr(args, ')'))) {
         *p = '\0';
      } else {
         ast_log(LOG_WARNING, "Can't find trailing parenthesis for function '%s(%s'?\n", function, args);
      }
   }
   return args;
}

int ast_func_read(struct ast_channel *chan, const char *function, char *workspace, size_t len)
{
   char *copy = ast_strdupa(function);
   char *args = func_args(copy);
   struct ast_custom_function *acfptr = ast_custom_function_find(copy);
   int res;
   struct ast_module_user *u = NULL;

   if (acfptr == NULL) {
      ast_log(LOG_ERROR, "Function %s not registered\n", copy);
   } else if (!acfptr->read && !acfptr->read2) {
      ast_log(LOG_ERROR, "Function %s cannot be read\n", copy);
   } else if (acfptr->read) {
      if (acfptr->mod) {
         u = __ast_module_user_add(acfptr->mod, chan);
      }
      res = acfptr->read(chan, copy, args, workspace, len);
      if (acfptr->mod && u) {
         __ast_module_user_remove(acfptr->mod, u);
      }
      return res;
   } else {
      struct ast_str *str = ast_str_create(16);
      if (acfptr->mod) {
         u = __ast_module_user_add(acfptr->mod, chan);
      }
      res = acfptr->read2(chan, copy, args, &str, 0);
      if (acfptr->mod && u) {
         __ast_module_user_remove(acfptr->mod, u);
      }
      ast_copy_string(workspace, ast_str_buffer(str), len > ast_str_size(str) ? ast_str_size(str) : len);
      ast_free(str);
      return res;
   }
   return -1;
}

int ast_func_read2(struct ast_channel *chan, const char *function, struct ast_str **str, ssize_t maxlen)
{
   char *copy = ast_strdupa(function);
   char *args = func_args(copy);
   struct ast_custom_function *acfptr = ast_custom_function_find(copy);
   int res;
   struct ast_module_user *u = NULL;

   if (acfptr == NULL) {
      ast_log(LOG_ERROR, "Function %s not registered\n", copy);
   } else if (!acfptr->read && !acfptr->read2) {
      ast_log(LOG_ERROR, "Function %s cannot be read\n", copy);
   } else {
      if (acfptr->mod) {
         u = __ast_module_user_add(acfptr->mod, chan);
      }
      ast_str_reset(*str);
      if (acfptr->read2) {
         /* ast_str enabled */
         res = acfptr->read2(chan, copy, args, str, maxlen);
      } else {
         /* Legacy function pointer, allocate buffer for result */
         int maxsize = ast_str_size(*str);
         if (maxlen > -1) {
            if (maxlen == 0) {
               if (acfptr->read_max) {
                  maxsize = acfptr->read_max;
               } else {
                  maxsize = VAR_BUF_SIZE;
               }
            } else {
               maxsize = maxlen;
            }
            ast_str_make_space(str, maxsize);
         }
         res = acfptr->read(chan, copy, args, ast_str_buffer(*str), maxsize);
      }
      if (acfptr->mod && u) {
         __ast_module_user_remove(acfptr->mod, u);
      }
      return res;
   }
   return -1;
}

int ast_func_write(struct ast_channel *chan, const char *function, const char *value)
{
   char *copy = ast_strdupa(function);
   char *args = func_args(copy);
   struct ast_custom_function *acfptr = ast_custom_function_find(copy);

   if (acfptr == NULL)
      ast_log(LOG_ERROR, "Function %s not registered\n", copy);
   else if (!acfptr->write)
      ast_log(LOG_ERROR, "Function %s cannot be written to\n", copy);
   else {
      int res;
      struct ast_module_user *u = NULL;
      if (acfptr->mod)
         u = __ast_module_user_add(acfptr->mod, chan);
      res = acfptr->write(chan, copy, args, value);
      if (acfptr->mod && u)
         __ast_module_user_remove(acfptr->mod, u);
      return res;
   }

   return -1;
}

void ast_str_substitute_variables_full(struct ast_str **buf, ssize_t maxlen, struct ast_channel *c, struct varshead *headp, const char *templ, size_t *used)
{
   /* Substitutes variables into buf, based on string templ */
   char *cp4 = NULL;
   const char *whereweare;
   int orig_size = 0;
   int offset, offset2, isfunction;
   const char *nextvar, *nextexp, *nextthing;
   const char *vars, *vare;
   char *finalvars;
   int pos, brackets, needsub, len;
   struct ast_str *substr1 = ast_str_create(16), *substr2 = NULL, *substr3 = ast_str_create(16);

   ast_str_reset(*buf);
   whereweare = templ;
   while (!ast_strlen_zero(whereweare)) {
      /* reset our buffer */
      ast_str_reset(substr3);

      /* Assume we're copying the whole remaining string */
      pos = strlen(whereweare);
      nextvar = NULL;
      nextexp = NULL;
      nextthing = strchr(whereweare, '$');
      if (nextthing) {
         switch (nextthing[1]) {
         case '{':
            nextvar = nextthing;
            pos = nextvar - whereweare;
            break;
         case '[':
            nextexp = nextthing;
            pos = nextexp - whereweare;
            break;
         default:
            pos = 1;
         }
      }

      if (pos) {
         /* Copy that many bytes */
         ast_str_append_substr(buf, maxlen, whereweare, pos);

         templ += pos;
         whereweare += pos;
      }

      if (nextvar) {
         /* We have a variable.  Find the start and end, and determine
            if we are going to have to recursively call ourselves on the
            contents */
         vars = vare = nextvar + 2;
         brackets = 1;
         needsub = 0;

         /* Find the end of it */
         while (brackets && *vare) {
            if ((vare[0] == '$') && (vare[1] == '{')) {
               needsub++;
            } else if (vare[0] == '{') {
               brackets++;
            } else if (vare[0] == '}') {
               brackets--;
            } else if ((vare[0] == '$') && (vare[1] == '['))
               needsub++;
            vare++;
         }
         if (brackets)
            ast_log(LOG_WARNING, "Error in extension logic (missing '}')\n");
         len = vare - vars - 1;

         /* Skip totally over variable string */
         whereweare += (len + 3);

         /* Store variable name (and truncate) */
         ast_str_set_substr(&substr1, 0, vars, len);
         ast_debug(5, "Evaluating '%s' (from '%s' len %d)\n", ast_str_buffer(substr1), vars, len);

         /* Substitute if necessary */
         if (needsub) {
            size_t used;
            if (!substr2) {
               substr2 = ast_str_create(16);
            }

            ast_str_substitute_variables_full(&substr2, 0, c, headp, ast_str_buffer(substr1), &used);
            finalvars = ast_str_buffer(substr2);
         } else {
            finalvars = ast_str_buffer(substr1);
         }

         parse_variable_name(finalvars, &offset, &offset2, &isfunction);
         if (isfunction) {
            /* Evaluate function */
            if (c || !headp) {
               cp4 = ast_func_read2(c, finalvars, &substr3, 0) ? NULL : ast_str_buffer(substr3);
            } else {
               struct varshead old;
               struct ast_channel *bogus = ast_dummy_channel_alloc();
               if (bogus) {
                  memcpy(&old, ast_channel_varshead(bogus), sizeof(old));
                  memcpy(ast_channel_varshead(bogus), headp, sizeof(*ast_channel_varshead(bogus)));
                  cp4 = ast_func_read2(c, finalvars, &substr3, 0) ? NULL : ast_str_buffer(substr3);
                  /* Don't deallocate the varshead that was passed in */
                  memcpy(ast_channel_varshead(bogus), &old, sizeof(*ast_channel_varshead(bogus)));
                  ast_channel_unref(bogus);
               } else {
                  ast_log(LOG_ERROR, "Unable to allocate bogus channel for variable substitution.  Function results may be blank.\n");
               }
            }
            ast_debug(2, "Function result is '%s'\n", cp4 ? cp4 : "(null)");
         } else {
            /* Retrieve variable value */
            ast_str_retrieve_variable(&substr3, 0, c, headp, finalvars);
            cp4 = ast_str_buffer(substr3);
         }
         if (cp4) {
            ast_str_substring(substr3, offset, offset2);
            ast_str_append(buf, maxlen, "%s", ast_str_buffer(substr3));
         }
      } else if (nextexp) {
         /* We have an expression.  Find the start and end, and determine
            if we are going to have to recursively call ourselves on the
            contents */
         vars = vare = nextexp + 2;
         brackets = 1;
         needsub = 0;

         /* Find the end of it */
         while (brackets && *vare) {
            if ((vare[0] == '$') && (vare[1] == '[')) {
               needsub++;
               brackets++;
               vare++;
            } else if (vare[0] == '[') {
               brackets++;
            } else if (vare[0] == ']') {
               brackets--;
            } else if ((vare[0] == '$') && (vare[1] == '{')) {
               needsub++;
               vare++;
            }
            vare++;
         }
         if (brackets)
            ast_log(LOG_WARNING, "Error in extension logic (missing ']')\n");
         len = vare - vars - 1;

         /* Skip totally over expression */
         whereweare += (len + 3);

         /* Store variable name (and truncate) */
         ast_str_set_substr(&substr1, 0, vars, len);

         /* Substitute if necessary */
         if (needsub) {
            size_t used;
            if (!substr2) {
               substr2 = ast_str_create(16);
            }

            ast_str_substitute_variables_full(&substr2, 0, c, headp, ast_str_buffer(substr1), &used);
            finalvars = ast_str_buffer(substr2);
         } else {
            finalvars = ast_str_buffer(substr1);
         }

         if (ast_str_expr(&substr3, 0, c, finalvars)) {
            ast_debug(2, "Expression result is '%s'\n", ast_str_buffer(substr3));
         }
         ast_str_append(buf, maxlen, "%s", ast_str_buffer(substr3));
      }
   }
   *used = ast_str_strlen(*buf) - orig_size;
   ast_free(substr1);
   ast_free(substr2);
   ast_free(substr3);
}

void ast_str_substitute_variables(struct ast_str **buf, ssize_t maxlen, struct ast_channel *chan, const char *templ)
{
   size_t used;
   ast_str_substitute_variables_full(buf, maxlen, chan, NULL, templ, &used);
}

void ast_str_substitute_variables_varshead(struct ast_str **buf, ssize_t maxlen, struct varshead *headp, const char *templ)
{
   size_t used;
   ast_str_substitute_variables_full(buf, maxlen, NULL, headp, templ, &used);
}

void pbx_substitute_variables_helper_full(struct ast_channel *c, struct varshead *headp, const char *cp1, char *cp2, int count, size_t *used)
{
   /* Substitutes variables into cp2, based on string cp1, cp2 NO LONGER NEEDS TO BE ZEROED OUT!!!!  */
   char *cp4 = NULL;
   const char *whereweare, *orig_cp2 = cp2;
   int length, offset, offset2, isfunction;
   char *workspace = NULL;
   char *ltmp = NULL, *var = NULL;
   char *nextvar, *nextexp, *nextthing;
   char *vars, *vare;
   int pos, brackets, needsub, len;

   *cp2 = 0; /* just in case nothing ends up there */
   whereweare = cp1;
   while (!ast_strlen_zero(whereweare) && count) {
      /* Assume we're copying the whole remaining string */
      pos = strlen(whereweare);
      nextvar = NULL;
      nextexp = NULL;
      nextthing = strchr(whereweare, '$');
      if (nextthing) {
         switch (nextthing[1]) {
         case '{':
            nextvar = nextthing;
            pos = nextvar - whereweare;
            break;
         case '[':
            nextexp = nextthing;
            pos = nextexp - whereweare;
            break;
         default:
            pos = 1;
         }
      }

      if (pos) {
         /* Can't copy more than 'count' bytes */
         if (pos > count)
            pos = count;

         /* Copy that many bytes */
         memcpy(cp2, whereweare, pos);

         count -= pos;
         cp2 += pos;
         whereweare += pos;
         *cp2 = 0;
      }

      if (nextvar) {
         /* We have a variable.  Find the start and end, and determine
            if we are going to have to recursively call ourselves on the
            contents */
         vars = vare = nextvar + 2;
         brackets = 1;
         needsub = 0;

         /* Find the end of it */
         while (brackets && *vare) {
            if ((vare[0] == '$') && (vare[1] == '{')) {
               needsub++;
            } else if (vare[0] == '{') {
               brackets++;
            } else if (vare[0] == '}') {
               brackets--;
            } else if ((vare[0] == '$') && (vare[1] == '['))
               needsub++;
            vare++;
         }
         if (brackets)
            ast_log(LOG_WARNING, "Error in extension logic (missing '}')\n");
         len = vare - vars - 1;

         /* Skip totally over variable string */
         whereweare += (len + 3);

         if (!var)
            var = ast_alloca(VAR_BUF_SIZE);

         /* Store variable name (and truncate) */
         ast_copy_string(var, vars, len + 1);

         /* Substitute if necessary */
         if (needsub) {
            size_t used;
            if (!ltmp)
               ltmp = ast_alloca(VAR_BUF_SIZE);

            pbx_substitute_variables_helper_full(c, headp, var, ltmp, VAR_BUF_SIZE - 1, &used);
            vars = ltmp;
         } else {
            vars = var;
         }

         if (!workspace)
            workspace = ast_alloca(VAR_BUF_SIZE);

         workspace[0] = '\0';

         parse_variable_name(vars, &offset, &offset2, &isfunction);
         if (isfunction) {
            /* Evaluate function */
            if (c || !headp)
               cp4 = ast_func_read(c, vars, workspace, VAR_BUF_SIZE) ? NULL : workspace;
            else {
               struct varshead old;
               struct ast_channel *c = ast_dummy_channel_alloc();
               if (c) {
                  memcpy(&old, ast_channel_varshead(c), sizeof(old));
                  memcpy(ast_channel_varshead(c), headp, sizeof(*ast_channel_varshead(c)));
                  cp4 = ast_func_read(c, vars, workspace, VAR_BUF_SIZE) ? NULL : workspace;
                  /* Don't deallocate the varshead that was passed in */
                  memcpy(ast_channel_varshead(c), &old, sizeof(*ast_channel_varshead(c)));
                  c = ast_channel_unref(c);
               } else {
                  ast_log(LOG_ERROR, "Unable to allocate bogus channel for variable substitution.  Function results may be blank.\n");
               }
            }
            ast_debug(2, "Function result is '%s'\n", cp4 ? cp4 : "(null)");
         } else {
            /* Retrieve variable value */
            pbx_retrieve_variable(c, vars, &cp4, workspace, VAR_BUF_SIZE, headp);
         }
         if (cp4) {
            cp4 = substring(cp4, offset, offset2, workspace, VAR_BUF_SIZE);

            length = strlen(cp4);
            if (length > count)
               length = count;
            memcpy(cp2, cp4, length);
            count -= length;
            cp2 += length;
            *cp2 = 0;
         }
      } else if (nextexp) {
         /* We have an expression.  Find the start and end, and determine
            if we are going to have to recursively call ourselves on the
            contents */
         vars = vare = nextexp + 2;
         brackets = 1;
         needsub = 0;

         /* Find the end of it */
         while (brackets && *vare) {
            if ((vare[0] == '$') && (vare[1] == '[')) {
               needsub++;
               brackets++;
               vare++;
            } else if (vare[0] == '[') {
               brackets++;
            } else if (vare[0] == ']') {
               brackets--;
            } else if ((vare[0] == '$') && (vare[1] == '{')) {
               needsub++;
               vare++;
            }
            vare++;
         }
         if (brackets)
            ast_log(LOG_WARNING, "Error in extension logic (missing ']')\n");
         len = vare - vars - 1;

         /* Skip totally over expression */
         whereweare += (len + 3);

         if (!var)
            var = ast_alloca(VAR_BUF_SIZE);

         /* Store variable name (and truncate) */
         ast_copy_string(var, vars, len + 1);

         /* Substitute if necessary */
         if (needsub) {
            size_t used;
            if (!ltmp)
               ltmp = ast_alloca(VAR_BUF_SIZE);

            pbx_substitute_variables_helper_full(c, headp, var, ltmp, VAR_BUF_SIZE - 1, &used);
            vars = ltmp;
         } else {
            vars = var;
         }

         length = ast_expr(vars, cp2, count, c);

         if (length) {
            ast_debug(1, "Expression result is '%s'\n", cp2);
            count -= length;
            cp2 += length;
            *cp2 = 0;
         }
      }
   }
   *used = cp2 - orig_cp2;
}

void pbx_substitute_variables_helper(struct ast_channel *c, const char *cp1, char *cp2, int count)
{
   size_t used;
   pbx_substitute_variables_helper_full(c, (c) ? ast_channel_varshead(c) : NULL, cp1, cp2, count, &used);
}

void pbx_substitute_variables_varshead(struct varshead *headp, const char *cp1, char *cp2, int count)
{
   size_t used;
   pbx_substitute_variables_helper_full(NULL, headp, cp1, cp2, count, &used);
}

static void pbx_substitute_variables(char *passdata, int datalen, struct ast_channel *c, struct ast_exten *e)
{
   const char *tmp;

   /* Nothing more to do */
   if (!e->data) {
      *passdata = '\0';
      return;
   }

   /* No variables or expressions in e->data, so why scan it? */
   if ((!(tmp = strchr(e->data, '$'))) || (!strstr(tmp, "${") && !strstr(tmp, "$["))) {
      ast_copy_string(passdata, e->data, datalen);
      return;
   }

   pbx_substitute_variables_helper(c, e->data, passdata, datalen - 1);
}

/*!
 * \brief The return value depends on the action:
 *
 * E_MATCH, E_CANMATCH, E_MATCHMORE require a real match,
 * and return 0 on failure, -1 on match;
 * E_FINDLABEL maps the label to a priority, and returns
 * the priority on success, ... XXX
 * E_SPAWN, spawn an application,
 *
 * \retval 0 on success.
 * \retval  -1 on failure.
 *
 * \note The channel is auto-serviced in this function, because doing an extension
 * match may block for a long time.  For example, if the lookup has to use a network
 * dialplan switch, such as DUNDi or IAX2, it may take a while.  However, the channel
 * auto-service code will queue up any important signalling frames to be processed
 * after this is done.
 */
static int pbx_extension_helper(struct ast_channel *c, struct ast_context *con,
  const char *context, const char *exten, int priority,
  const char *label, const char *callerid, enum ext_match_t action, int *found, int combined_find_spawn)
{
   struct ast_exten *e;
   struct ast_app *app;
   int res;
   struct pbx_find_info q = { .stacklen = 0 }; /* the rest is reset in pbx_find_extension */
   char passdata[EXT_DATA_SIZE];

   int matching_action = (action == E_MATCH || action == E_CANMATCH || action == E_MATCHMORE);

   ast_rdlock_contexts();
   if (found)
      *found = 0;

   e = pbx_find_extension(c, con, &q, context, exten, priority, label, callerid, action);
   if (e) {
      if (found)
         *found = 1;
      if (matching_action) {
         ast_unlock_contexts();
         return -1;  /* success, we found it */
      } else if (action == E_FINDLABEL) { /* map the label to a priority */
         res = e->priority;
         ast_unlock_contexts();
         return res; /* the priority we were looking for */
      } else { /* spawn */
         if (!e->cached_app)
            e->cached_app = pbx_findapp(e->app);
         app = e->cached_app;
         ast_unlock_contexts();
         if (!app) {
            ast_log(LOG_WARNING, "No application '%s' for extension (%s, %s, %d)\n", e->app, context, exten, priority);
            return -1;
         }
         if (ast_channel_context(c) != context)
            ast_channel_context_set(c, context);
         if (ast_channel_exten(c) != exten)
            ast_channel_exten_set(c, exten);
         ast_channel_priority_set(c, priority);
         pbx_substitute_variables(passdata, sizeof(passdata), c, e);
#ifdef CHANNEL_TRACE
         ast_channel_trace_update(c);
#endif
         ast_debug(1, "Launching '%s'\n", app->name);
         {
            char tmp[80], tmp2[80], tmp3[EXT_DATA_SIZE];
            ast_verb(3, "Executing [%s@%s:%d] %s(\"%s\", \"%s\") %s\n",
               exten, context, priority,
               term_color(tmp, app->name, COLOR_BRCYAN, 0, sizeof(tmp)),
               term_color(tmp2, ast_channel_name(c), COLOR_BRMAGENTA, 0, sizeof(tmp2)),
               term_color(tmp3, passdata, COLOR_BRMAGENTA, 0, sizeof(tmp3)),
               "in new stack");
         }
         /*** DOCUMENTATION
            <managerEventInstance>
               <synopsis>Raised when a channel enters a new context, extension, priority.</synopsis>
               <syntax>
                  <parameter name="Application">
                     <para>The application about to be executed.</para>
                  </parameter>
                  <parameter name="AppData">
                     <para>The data to be passed to the application.</para>
                  </parameter>
               </syntax>
            </managerEventInstance>
         ***/
         manager_event(EVENT_FLAG_DIALPLAN, "Newexten",
               "Channel: %s\r\n"
               "Context: %s\r\n"
               "Extension: %s\r\n"
               "Priority: %d\r\n"
               "Application: %s\r\n"
               "AppData: %s\r\n"
               "Uniqueid: %s\r\n",
               ast_channel_name(c), ast_channel_context(c), ast_channel_exten(c), ast_channel_priority(c), app->name, passdata, ast_channel_uniqueid(c));
         return pbx_exec(c, app, passdata);  /* 0 on success, -1 on failure */
      }
   } else if (q.swo) {  /* not found here, but in another switch */
      if (found)
         *found = 1;
      ast_unlock_contexts();
      if (matching_action) {
         return -1;
      } else {
         if (!q.swo->exec) {
            ast_log(LOG_WARNING, "No execution engine for switch %s\n", q.swo->name);
            res = -1;
         }
         return q.swo->exec(c, q.foundcontext ? q.foundcontext : context, exten, priority, callerid, q.data);
      }
   } else { /* not found anywhere, see what happened */
      ast_unlock_contexts();
      /* Using S_OR here because Solaris doesn't like NULL being passed to ast_log */
      switch (q.status) {
      case STATUS_NO_CONTEXT:
         if (!matching_action && !combined_find_spawn)
            ast_log(LOG_NOTICE, "Cannot find extension context '%s'\n", S_OR(context, ""));
         break;
      case STATUS_NO_EXTENSION:
         if (!matching_action && !combined_find_spawn)
            ast_log(LOG_NOTICE, "Cannot find extension '%s' in context '%s'\n", exten, S_OR(context, ""));
         break;
      case STATUS_NO_PRIORITY:
         if (!matching_action && !combined_find_spawn)
            ast_log(LOG_NOTICE, "No such priority %d in extension '%s' in context '%s'\n", priority, exten, S_OR(context, ""));
         break;
      case STATUS_NO_LABEL:
         if (context && !combined_find_spawn)
            ast_log(LOG_NOTICE, "No such label '%s' in extension '%s' in context '%s'\n", label, exten, S_OR(context, ""));
         break;
      default:
         ast_debug(1, "Shouldn't happen!\n");
      }

      return (matching_action) ? 0 : -1;
   }
}

/*! \brief Find hint for given extension in context */
static struct ast_exten *ast_hint_extension_nolock(struct ast_channel *c, const char *context, const char *exten)
{
   struct pbx_find_info q = { .stacklen = 0 }; /* the rest is set in pbx_find_context */
   return pbx_find_extension(c, NULL, &q, context, exten, PRIORITY_HINT, NULL, "", E_MATCH);
}

static struct ast_exten *ast_hint_extension(struct ast_channel *c, const char *context, const char *exten)
{
   struct ast_exten *e;
   ast_rdlock_contexts();
   e = ast_hint_extension_nolock(c, context, exten);
   ast_unlock_contexts();
   return e;
}

enum ast_extension_states ast_devstate_to_extenstate(enum ast_device_state devstate)
{
   switch (devstate) {
   case AST_DEVICE_ONHOLD:
      return AST_EXTENSION_ONHOLD;
   case AST_DEVICE_BUSY:
      return AST_EXTENSION_BUSY;
   case AST_DEVICE_UNKNOWN:
      return AST_EXTENSION_NOT_INUSE;
   case AST_DEVICE_UNAVAILABLE:
   case AST_DEVICE_INVALID:
      return AST_EXTENSION_UNAVAILABLE;
   case AST_DEVICE_RINGINUSE:
      return (AST_EXTENSION_INUSE | AST_EXTENSION_RINGING);
   case AST_DEVICE_RINGING:
      return AST_EXTENSION_RINGING;
   case AST_DEVICE_INUSE:
      return AST_EXTENSION_INUSE;
   case AST_DEVICE_NOT_INUSE:
      return AST_EXTENSION_NOT_INUSE;
   case AST_DEVICE_TOTAL: /* not a device state, included for completeness */
      break;
   }

   return AST_EXTENSION_NOT_INUSE;
}

/*!
 * \internal
 * \brief Parse out the presence portion of the hint string
 */
static char *parse_hint_presence(struct ast_str *hint_args)
{
   char *copy = ast_strdupa(ast_str_buffer(hint_args));
   char *tmp = "";

   if ((tmp = strrchr(copy, ','))) {
      *tmp = '\0';
      tmp++;
   } else {
      return NULL;
   }
   ast_str_set(&hint_args, 0, "%s", tmp);
   return ast_str_buffer(hint_args);
}

/*!
 * \internal
 * \brief Parse out the device portion of the hint string
 */
static char *parse_hint_device(struct ast_str *hint_args)
{
   char *copy = ast_strdupa(ast_str_buffer(hint_args));
   char *tmp;

   if ((tmp = strrchr(copy, ','))) {
      *tmp = '\0';
   }

   ast_str_set(&hint_args, 0, "%s", copy);
   return ast_str_buffer(hint_args);
}

static void device_state_info_dt(void *obj)
{
   struct ast_device_state_info *info = obj;

   ao2_cleanup(info->causing_channel);
}

static struct ao2_container *alloc_device_state_info(void)
{
   return ao2_container_alloc_options(AO2_ALLOC_OPT_LOCK_NOLOCK, 1, NULL, NULL);
}

static int ast_extension_state3(struct ast_str *hint_app, struct ao2_container *device_state_info)
{
   char *cur;
   char *rest;
   struct ast_devstate_aggregate agg;

   /* One or more devices separated with a & character */
   rest = parse_hint_device(hint_app);

   ast_devstate_aggregate_init(&agg);
   while ((cur = strsep(&rest, "&"))) {
      enum ast_device_state state = ast_device_state(cur);

      ast_devstate_aggregate_add(&agg, state);
      if (device_state_info) {
         struct ast_device_state_info *obj;

         obj = ao2_alloc_options(sizeof(*obj) + strlen(cur), device_state_info_dt, AO2_ALLOC_OPT_LOCK_NOLOCK);
         /* if failed we cannot add this device */
         if (obj) {
            obj->device_state = state;
            strcpy(obj->device_name, cur);
            ao2_link(device_state_info, obj);
            ao2_ref(obj, -1);
         }
      }
   }

   return ast_devstate_to_extenstate(ast_devstate_aggregate_result(&agg));
}

/*! \brief Check state of extension by using hints */
static int ast_extension_state2(struct ast_exten *e, struct ao2_container *device_state_info)
{
   struct ast_str *hint_app = ast_str_thread_get(&extensionstate_buf, 32);

   if (!e || !hint_app) {
      return -1;
   }

   ast_str_set(&hint_app, 0, "%s", ast_get_extension_app(e));
   return ast_extension_state3(hint_app, device_state_info);
}

/*! \brief Return extension_state as string */
const char *ast_extension_state2str(int extension_state)
{
   int i;

   for (i = 0; (i < ARRAY_LEN(extension_states)); i++) {
      if (extension_states[i].extension_state == extension_state)
         return extension_states[i].text;
   }
   return "Unknown";
}

/*! \internal \brief Check extension state for an extension by using hint */
static int internal_extension_state_extended(struct ast_channel *c, const char *context, const char *exten,
   struct ao2_container *device_state_info)
{
   struct ast_exten *e;

   if (!(e = ast_hint_extension(c, context, exten))) {  /* Do we have a hint for this extension ? */
      return -1;                   /* No hint, return -1 */
   }

   if (e->exten[0] == '_') {
      /* Create this hint on-the-fly */
      ast_add_extension(e->parent->name, 0, exten, e->priority, e->label,
         e->matchcid ? e->cidmatch : NULL, e->app, ast_strdup(e->data), ast_free_ptr,
         e->registrar);
      if (!(e = ast_hint_extension(c, context, exten))) {
         /* Improbable, but not impossible */
         return -1;
      }
   }

   return ast_extension_state2(e, device_state_info);  /* Check all devices in the hint */
}

/*! \brief Check extension state for an extension by using hint */
int ast_extension_state(struct ast_channel *c, const char *context, const char *exten)
{
   return internal_extension_state_extended(c, context, exten, NULL);
}

/*! \brief Check extended extension state for an extension by using hint */
int ast_extension_state_extended(struct ast_channel *c, const char *context, const char *exten,
   struct ao2_container **device_state_info)
{
   struct ao2_container *container = NULL;
   int ret;

   if (device_state_info) {
      container = alloc_device_state_info();
   }

   ret = internal_extension_state_extended(c, context, exten, container);
   if (ret < 0 && container) {
      ao2_ref(container, -1);
      container = NULL;
   }

   if (device_state_info) {
      get_device_state_causing_channels(container);
      *device_state_info = container;
   }

   return ret;
}

static int extension_presence_state_helper(struct ast_exten *e, char **subtype, char **message)
{
   struct ast_str *hint_app = ast_str_thread_get(&extensionstate_buf, 32);
   char *presence_provider;
   const char *app;

   if (!e || !hint_app) {
      return -1;
   }

   app = ast_get_extension_app(e);
   if (ast_strlen_zero(app)) {
      return -1;
   }

   ast_str_set(&hint_app, 0, "%s", app);
   presence_provider = parse_hint_presence(hint_app);

   if (ast_strlen_zero(presence_provider)) {
      /* No presence string in the hint */
      return 0;
   }

   return ast_presence_state(presence_provider, subtype, message);
}

int ast_hint_presence_state(struct ast_channel *c, const char *context, const char *exten, char **subtype, char **message)
{
   struct ast_exten *e;

   if (!(e = ast_hint_extension(c, context, exten))) {  /* Do we have a hint for this extension ? */
      return -1;                   /* No hint, return -1 */
   }

   if (e->exten[0] == '_') {
      /* Create this hint on-the-fly */
      ast_add_extension(e->parent->name, 0, exten, e->priority, e->label,
         e->matchcid ? e->cidmatch : NULL, e->app, ast_strdup(e->data), ast_free_ptr,
         e->registrar);
      if (!(e = ast_hint_extension(c, context, exten))) {
         /* Improbable, but not impossible */
         return -1;
      }
   }

   return extension_presence_state_helper(e, subtype, message);
}

static int execute_state_callback(ast_state_cb_type cb,
   const char *context,
   const char *exten,
   void *data,
   enum ast_state_cb_update_reason reason,
   struct ast_hint *hint,
   struct ao2_container *device_state_info)
{
   int res = 0;
   struct ast_state_cb_info info = { 0, };

   info.reason = reason;

   /* Copy over current hint data */
   if (hint) {
      ao2_lock(hint);
      info.exten_state = hint->laststate;
      info.device_state_info = device_state_info;
      info.presence_state = hint->last_presence_state;
      if (!(ast_strlen_zero(hint->last_presence_subtype))) {
         info.presence_subtype = ast_strdupa(hint->last_presence_subtype);
      } else {
         info.presence_subtype = "";
      }
      if (!(ast_strlen_zero(hint->last_presence_message))) {
         info.presence_message = ast_strdupa(hint->last_presence_message);
      } else {
         info.presence_message = "";
      }
      ao2_unlock(hint);
   } else {
      info.exten_state = AST_EXTENSION_REMOVED;
   }

   /* NOTE: The casts will not be needed for v10 and later */
   res = cb((char *) context, (char *) exten, &info, data);

   return res;
}

static int handle_presencechange(void *datap)
{
   struct ast_hint *hint;
   struct ast_str *hint_app = NULL;
   struct presencechange *pc = datap;
   struct ao2_iterator i;
   struct ao2_iterator cb_iter;
   char context_name[AST_MAX_CONTEXT];
   char exten_name[AST_MAX_EXTENSION];
   int res = -1;

   hint_app = ast_str_create(1024);
   if (!hint_app) {
      goto presencechange_cleanup;
   }

   ast_mutex_lock(&context_merge_lock);/* Hold off ast_merge_contexts_and_delete */
   i = ao2_iterator_init(hints, 0);
   for (; (hint = ao2_iterator_next(&i)); ao2_ref(hint, -1)) {
      struct ast_state_cb *state_cb;
      const char *app;
      char *parse;

      ao2_lock(hint);

      if (!hint->exten) {
         /* The extension has already been destroyed */
         ao2_unlock(hint);
         continue;
      }

      /* Does this hint monitor the device that changed state? */
      app = ast_get_extension_app(hint->exten);
      if (ast_strlen_zero(app)) {
         /* The hint does not monitor presence at all. */
         ao2_unlock(hint);
         continue;
      }

      ast_str_set(&hint_app, 0, "%s", app);
      parse = parse_hint_presence(hint_app);
      if (ast_strlen_zero(parse)) {
         ao2_unlock(hint);
         continue;
      }
      if (strcasecmp(parse, pc->provider)) {
         /* The hint does not monitor the presence provider. */
         ao2_unlock(hint);
         continue;
      }

      /*
       * Save off strings in case the hint extension gets destroyed
       * while we are notifying the watchers.
       */
      ast_copy_string(context_name,
         ast_get_context_name(ast_get_extension_context(hint->exten)),
         sizeof(context_name));
      ast_copy_string(exten_name, ast_get_extension_name(hint->exten),
         sizeof(exten_name));
      ast_str_set(&hint_app, 0, "%s", ast_get_extension_app(hint->exten));

      /* Check to see if update is necessary */
      if ((hint->last_presence_state == pc->state) &&
         ((hint->last_presence_subtype && pc->subtype && !strcmp(hint->last_presence_subtype, pc->subtype)) || (!hint->last_presence_subtype && !pc->subtype)) &&
         ((hint->last_presence_message && pc->message && !strcmp(hint->last_presence_message, pc->message)) || (!hint->last_presence_message && !pc->message))) {

         /* this update is the same as the last, do nothing */
         ao2_unlock(hint);
         continue;
      }

      /* update new values */
      ast_free(hint->last_presence_subtype);
      ast_free(hint->last_presence_message);
      hint->last_presence_state = pc->state;
      hint->last_presence_subtype = pc->subtype ? ast_strdup(pc->subtype) : NULL;
      hint->last_presence_message = pc->message ? ast_strdup(pc->message) : NULL;

      ao2_unlock(hint);

      /* For general callbacks */
      cb_iter = ao2_iterator_init(statecbs, 0);
      for (; (state_cb = ao2_iterator_next(&cb_iter)); ao2_ref(state_cb, -1)) {
         execute_state_callback(state_cb->change_cb,
            context_name,
            exten_name,
            state_cb->data,
            AST_HINT_UPDATE_PRESENCE,
            hint,
            NULL);
      }
      ao2_iterator_destroy(&cb_iter);

      /* For extension callbacks */
      cb_iter = ao2_iterator_init(hint->callbacks, 0);
      for (; (state_cb = ao2_iterator_next(&cb_iter)); ao2_ref(state_cb, -1)) {
         execute_state_callback(state_cb->change_cb,
            context_name,
            exten_name,
            state_cb->data,
            AST_HINT_UPDATE_PRESENCE,
            hint,
            NULL);
      }
      ao2_iterator_destroy(&cb_iter);
   }
   ao2_iterator_destroy(&i);
   ast_mutex_unlock(&context_merge_lock);

   res = 0;

presencechange_cleanup:
   ast_free(hint_app);
   ao2_ref(pc, -1);

   return res;
}

/*!
 * /internal
 * /brief Identify a channel for every device which is supposedly responsible for the device state.
 *
 * Especially when the device is ringing, the oldest ringing channel is chosen.
 * For all other cases the first encountered channel in the specific state is chosen.
 */
static void get_device_state_causing_channels(struct ao2_container *c)
{
   struct ao2_iterator iter;
   struct ast_device_state_info *info;
   struct ast_channel *chan;

   if (!c || !ao2_container_count(c)) {
      return;
   }
   iter = ao2_iterator_init(c, 0);
   for (; (info = ao2_iterator_next(&iter)); ao2_ref(info, -1)) {
      enum ast_channel_state search_state = 0; /* prevent false uninit warning */
      char match[AST_CHANNEL_NAME];
      struct ast_channel_iterator *chan_iter;
      struct timeval chantime = {0, }; /* prevent false uninit warning */

      switch (info->device_state) {
      case AST_DEVICE_RINGING:
      case AST_DEVICE_RINGINUSE:
         /* find ringing channel */
         search_state = AST_STATE_RINGING;
         break;
      case AST_DEVICE_BUSY:
         /* find busy channel */
         search_state = AST_STATE_BUSY;
         break;
      case AST_DEVICE_ONHOLD:
      case AST_DEVICE_INUSE:
         /* find up channel */
         search_state = AST_STATE_UP;
         break;
      case AST_DEVICE_UNKNOWN:
      case AST_DEVICE_NOT_INUSE:
      case AST_DEVICE_INVALID:
      case AST_DEVICE_UNAVAILABLE:
      case AST_DEVICE_TOTAL /* not a state */:
         /* no channels are of interest */
         continue;
      }

      /* iterate over all channels of the device */
           snprintf(match, sizeof(match), "%s-", info->device_name);
      chan_iter = ast_channel_iterator_by_name_new(match, strlen(match));
      for (; (chan = ast_channel_iterator_next(chan_iter)); ast_channel_unref(chan)) {
         ast_channel_lock(chan);
         /* this channel's state doesn't match */
         if (search_state != ast_channel_state(chan)) {
            ast_channel_unlock(chan);
            continue;
         }
         /* any non-ringing channel will fit */
         if (search_state != AST_STATE_RINGING) {
            ast_channel_unlock(chan);
            info->causing_channel = chan; /* is kept ref'd! */
            break;
         }
         /* but we need the oldest ringing channel of the device to match with undirected pickup */
         if (!info->causing_channel) {
            chantime = ast_channel_creationtime(chan);
            ast_channel_ref(chan); /* must ref it! */
            info->causing_channel = chan;
         } else if (ast_tvcmp(ast_channel_creationtime(chan), chantime) < 0) {
            chantime = ast_channel_creationtime(chan);
            ast_channel_unref(info->causing_channel);
            ast_channel_ref(chan); /* must ref it! */
            info->causing_channel = chan;
         }
         ast_channel_unlock(chan);
      }
      ast_channel_iterator_destroy(chan_iter);
   }
   ao2_iterator_destroy(&iter);
}

static int handle_statechange(void *datap)
{
   struct ast_hint *hint;
   struct ast_str *hint_app;
   struct ast_hintdevice *device;
   struct ast_hintdevice *cmpdevice;
   struct statechange *sc = datap;
   struct ao2_iterator *dev_iter;
   struct ao2_iterator cb_iter;
   char context_name[AST_MAX_CONTEXT];
   char exten_name[AST_MAX_EXTENSION];

   if (ao2_container_count(hintdevices) == 0) {
      /* There are no hints monitoring devices. */
      ast_free(sc);
      return 0;
   }

   hint_app = ast_str_create(1024);
   if (!hint_app) {
      ast_free(sc);
      return -1;
   }

   cmpdevice = ast_alloca(sizeof(*cmpdevice) + strlen(sc->dev));
   strcpy(cmpdevice->hintdevice, sc->dev);

   ast_mutex_lock(&context_merge_lock);/* Hold off ast_merge_contexts_and_delete */
   dev_iter = ao2_t_callback(hintdevices,
      OBJ_POINTER | OBJ_MULTIPLE,
      hintdevice_cmp_multiple,
      cmpdevice,
      "find devices in container");
   if (!dev_iter) {
      ast_mutex_unlock(&context_merge_lock);
      ast_free(hint_app);
      ast_free(sc);
      return -1;
   }

   for (; (device = ao2_iterator_next(dev_iter)); ao2_t_ref(device, -1, "Next device")) {
      struct ast_state_cb *state_cb;
      int state;
      int same_state;
      struct ao2_container *device_state_info;
      int first_extended_cb_call = 1;

      if (!device->hint) {
         /* Should never happen. */
         continue;
      }
      hint = device->hint;

      ao2_lock(hint);
      if (!hint->exten) {
         /* The extension has already been destroyed */
         ao2_unlock(hint);
         continue;
      }

      /*
       * Save off strings in case the hint extension gets destroyed
       * while we are notifying the watchers.
       */
      ast_copy_string(context_name,
         ast_get_context_name(ast_get_extension_context(hint->exten)),
         sizeof(context_name));
      ast_copy_string(exten_name, ast_get_extension_name(hint->exten),
         sizeof(exten_name));
      ast_str_set(&hint_app, 0, "%s", ast_get_extension_app(hint->exten));
      ao2_unlock(hint);

      /*
       * Get device state for this hint.
       *
       * NOTE: We cannot hold any locks while determining the hint
       * device state or notifying the watchers without causing a
       * deadlock.  (conlock, hints, and hint)
       */
      /* Make a container so state3 can fill it if we wish.
       * If that failed we simply do not provide the extended state info.
       */
      device_state_info = alloc_device_state_info();
      state = ast_extension_state3(hint_app, device_state_info);
      if ((same_state = state == hint->laststate) && (~state & AST_EXTENSION_RINGING)) {
         ao2_cleanup(device_state_info);
         continue;
      }

      /* Device state changed since last check - notify the watchers. */
      hint->laststate = state;   /* record we saw the change */

      /* For general callbacks */
      cb_iter = ao2_iterator_init(statecbs, 0);
      for (; !same_state && (state_cb = ao2_iterator_next(&cb_iter)); ao2_ref(state_cb, -1)) {
         execute_state_callback(state_cb->change_cb,
            context_name,
            exten_name,
            state_cb->data,
            AST_HINT_UPDATE_DEVICE,
            hint,
            NULL);
      }
      ao2_iterator_destroy(&cb_iter);

      /* For extension callbacks */
      /* extended callbacks are called when the state changed or when AST_EVENT_RINGING is
       * included. Normal callbacks are only called when the state changed.
       */
      cb_iter = ao2_iterator_init(hint->callbacks, 0);
      for (; (state_cb = ao2_iterator_next(&cb_iter)); ao2_ref(state_cb, -1)) {
         if (state_cb->extended && first_extended_cb_call) {
            /* Fill detailed device_state_info now that we know it is used by extd. callback */
            first_extended_cb_call = 0;
            get_device_state_causing_channels(device_state_info);
         }
         if (state_cb->extended || !same_state) {
            execute_state_callback(state_cb->change_cb,
               context_name,
               exten_name,
               state_cb->data,
               AST_HINT_UPDATE_DEVICE,
               hint,
               state_cb->extended ? device_state_info : NULL);
         }
      }
      ao2_iterator_destroy(&cb_iter);

      ao2_cleanup(device_state_info);
   }
   ast_mutex_unlock(&context_merge_lock);

   ao2_iterator_destroy(dev_iter);
   ast_free(hint_app);
   ast_free(sc);
   return 0;
}

/*!
 * \internal
 * \brief Destroy the given state callback object.
 *
 * \param doomed State callback to destroy.
 *
 * \return Nothing
 */
static void destroy_state_cb(void *doomed)
{
   struct ast_state_cb *state_cb = doomed;

   if (state_cb->destroy_cb) {
      state_cb->destroy_cb(state_cb->id, state_cb->data);
   }
}

/*! \internal \brief Add watcher for extension states with destructor */
static int extension_state_add_destroy(const char *context, const char *exten,
   ast_state_cb_type change_cb, ast_state_cb_destroy_type destroy_cb, void *data, int extended)
{
   struct ast_hint *hint;
   struct ast_state_cb *state_cb;
   struct ast_exten *e;
   int id;

   /* If there's no context and extension:  add callback to statecbs list */
   if (!context && !exten) {
      /* Prevent multiple adds from adding the same change_cb at the same time. */
      ao2_lock(statecbs);

      /* Remove any existing change_cb. */
      ao2_find(statecbs, change_cb, OBJ_UNLINK | OBJ_NODATA);

      /* Now insert the change_cb */
      if (!(state_cb = ao2_alloc(sizeof(*state_cb), destroy_state_cb))) {
         ao2_unlock(statecbs);
         return -1;
      }
      state_cb->id = 0;
      state_cb->change_cb = change_cb;
      state_cb->destroy_cb = destroy_cb;
      state_cb->data = data;
      state_cb->extended = extended;
      ao2_link(statecbs, state_cb);

      ao2_ref(state_cb, -1);
      ao2_unlock(statecbs);
      return 0;
   }

   if (!context || !exten)
      return -1;

   /* This callback type is for only one hint, so get the hint */
   e = ast_hint_extension(NULL, context, exten);
   if (!e) {
      return -1;
   }

   /* If this is a pattern, dynamically create a new extension for this
    * particular match.  Note that this will only happen once for each
    * individual extension, because the pattern will no longer match first.
    */
   if (e->exten[0] == '_') {
      ast_add_extension(e->parent->name, 0, exten, e->priority, e->label,
         e->matchcid ? e->cidmatch : NULL, e->app, ast_strdup(e->data), ast_free_ptr,
         e->registrar);
      e = ast_hint_extension(NULL, context, exten);
      if (!e || e->exten[0] == '_') {
         return -1;
      }
   }

   /* Find the hint in the hints container */
   ao2_lock(hints);/* Locked to hold off ast_merge_contexts_and_delete */
   hint = ao2_find(hints, e, 0);
   if (!hint) {
      ao2_unlock(hints);
      return -1;
   }

   /* Now insert the callback in the callback list  */
   if (!(state_cb = ao2_alloc(sizeof(*state_cb), destroy_state_cb))) {
      ao2_ref(hint, -1);
      ao2_unlock(hints);
      return -1;
   }
   do {
      id = stateid++;      /* Unique ID for this callback */
      /* Do not allow id to ever be -1 or 0. */
   } while (id == -1 || id == 0);
   state_cb->id = id;
   state_cb->change_cb = change_cb; /* Pointer to callback routine */
   state_cb->destroy_cb = destroy_cb;
   state_cb->data = data;     /* Data for the callback */
   state_cb->extended = extended;
   ao2_link(hint->callbacks, state_cb);

   ao2_ref(state_cb, -1);
   ao2_ref(hint, -1);
   ao2_unlock(hints);

   return id;
}

/*! \brief Add watcher for extension states with destructor */
int ast_extension_state_add_destroy(const char *context, const char *exten,
   ast_state_cb_type change_cb, ast_state_cb_destroy_type destroy_cb, void *data)
{
   return extension_state_add_destroy(context, exten, change_cb, destroy_cb, data, 0);
}

/*! \brief Add watcher for extension states */
int ast_extension_state_add(const char *context, const char *exten,
   ast_state_cb_type change_cb, void *data)
{
   return extension_state_add_destroy(context, exten, change_cb, NULL, data, 0);
}

/*! \brief Add watcher for extended extension states with destructor */
int ast_extension_state_add_destroy_extended(const char *context, const char *exten,
   ast_state_cb_type change_cb, ast_state_cb_destroy_type destroy_cb, void *data)
{
   return extension_state_add_destroy(context, exten, change_cb, destroy_cb, data, 1);
}

/*! \brief Add watcher for extended extension states */
int ast_extension_state_add_extended(const char *context, const char *exten,
   ast_state_cb_type change_cb, void *data)
{
   return extension_state_add_destroy(context, exten, change_cb, NULL, data, 1);
}

/*! \brief Find Hint by callback id */
static int find_hint_by_cb_id(void *obj, void *arg, int flags)
{
   struct ast_state_cb *state_cb;
   const struct ast_hint *hint = obj;
   int *id = arg;

   if ((state_cb = ao2_find(hint->callbacks, id, 0))) {
      ao2_ref(state_cb, -1);
      return CMP_MATCH | CMP_STOP;
   }

   return 0;
}

/*! \brief  ast_extension_state_del: Remove a watcher from the callback list */
int ast_extension_state_del(int id, ast_state_cb_type change_cb)
{
   struct ast_state_cb *p_cur;
   int ret = -1;

   if (!id) {  /* id == 0 is a callback without extension */
      if (!change_cb) {
         return ret;
      }
      p_cur = ao2_find(statecbs, change_cb, OBJ_UNLINK);
      if (p_cur) {
         ret = 0;
         ao2_ref(p_cur, -1);
      }
   } else { /* callback with extension, find the callback based on ID */
      struct ast_hint *hint;

      ao2_lock(hints);/* Locked to hold off ast_merge_contexts_and_delete */
      hint = ao2_callback(hints, 0, find_hint_by_cb_id, &id);
      if (hint) {
         p_cur = ao2_find(hint->callbacks, &id, OBJ_UNLINK);
         if (p_cur) {
            ret = 0;
            ao2_ref(p_cur, -1);
         }
         ao2_ref(hint, -1);
      }
      ao2_unlock(hints);
   }

   return ret;
}

static int hint_id_cmp(void *obj, void *arg, int flags)
{
   const struct ast_state_cb *cb = obj;
   int *id = arg;

   return (cb->id == *id) ? CMP_MATCH | CMP_STOP : 0;
}

/*!
 * \internal
 * \brief Destroy the given hint object.
 *
 * \param obj Hint to destroy.
 *
 * \return Nothing
 */
static void destroy_hint(void *obj)
{
   struct ast_hint *hint = obj;

   if (hint->callbacks) {
      struct ast_state_cb *state_cb;
      const char *context_name;
      const char *exten_name;

      if (hint->exten) {
         context_name = ast_get_context_name(ast_get_extension_context(hint->exten));
         exten_name = ast_get_extension_name(hint->exten);
         hint->exten = NULL;
      } else {
         /* The extension has already been destroyed */
         context_name = hint->context_name;
         exten_name = hint->exten_name;
      }
      hint->laststate = AST_EXTENSION_DEACTIVATED;
      while ((state_cb = ao2_callback(hint->callbacks, OBJ_UNLINK, NULL, NULL))) {
         /* Notify with -1 and remove all callbacks */
         execute_state_callback(state_cb->change_cb,
            context_name,
            exten_name,
            state_cb->data,
            AST_HINT_UPDATE_DEVICE,
            hint,
            NULL);
         ao2_ref(state_cb, -1);
      }
      ao2_ref(hint->callbacks, -1);
   }
   ast_free(hint->last_presence_subtype);
   ast_free(hint->last_presence_message);
}

/*! \brief Remove hint from extension */
static int ast_remove_hint(struct ast_exten *e)
{
   /* Cleanup the Notifys if hint is removed */
   struct ast_hint *hint;

   if (!e) {
      return -1;
   }

   hint = ao2_find(hints, e, OBJ_UNLINK);
   if (!hint) {
      return -1;
   }

   remove_hintdevice(hint);

   /*
    * The extension is being destroyed so we must save some
    * information to notify that the extension is deactivated.
    */
   ao2_lock(hint);
   ast_copy_string(hint->context_name,
      ast_get_context_name(ast_get_extension_context(hint->exten)),
      sizeof(hint->context_name));
   ast_copy_string(hint->exten_name, ast_get_extension_name(hint->exten),
      sizeof(hint->exten_name));
   hint->exten = NULL;
   ao2_unlock(hint);

   ao2_ref(hint, -1);

   return 0;
}

/*! \brief Add hint to hint list, check initial extension state */
static int ast_add_hint(struct ast_exten *e)
{
   struct ast_hint *hint_new;
   struct ast_hint *hint_found;
   char *message = NULL;
   char *subtype = NULL;
   int presence_state;

   if (!e) {
      return -1;
   }

   /*
    * We must create the hint we wish to add before determining if
    * it is already in the hints container to avoid possible
    * deadlock when getting the current extension state.
    */
   hint_new = ao2_alloc(sizeof(*hint_new), destroy_hint);
   if (!hint_new) {
      return -1;
   }

   /* Initialize new hint. */
   hint_new->callbacks = ao2_container_alloc(1, NULL, hint_id_cmp);
   if (!hint_new->callbacks) {
      ao2_ref(hint_new, -1);
      return -1;
   }
   hint_new->exten = e;
   hint_new->laststate = ast_extension_state2(e, NULL);
   if ((presence_state = extension_presence_state_helper(e, &subtype, &message)) > 0) {
      hint_new->last_presence_state = presence_state;
      hint_new->last_presence_subtype = subtype;
      hint_new->last_presence_message = message;
      message = subtype = NULL;
   }

   /* Prevent multiple add hints from adding the same hint at the same time. */
   ao2_lock(hints);

   /* Search if hint exists, do nothing */
   hint_found = ao2_find(hints, e, 0);
   if (hint_found) {
      ao2_ref(hint_found, -1);
      ao2_unlock(hints);
      ao2_ref(hint_new, -1);
      ast_debug(2, "HINTS: Not re-adding existing hint %s: %s\n",
         ast_get_extension_name(e), ast_get_extension_app(e));
      return -1;
   }

   /* Add new hint to the hints container */
   ast_debug(2, "HINTS: Adding hint %s: %s\n",
      ast_get_extension_name(e), ast_get_extension_app(e));
   ao2_link(hints, hint_new);
   if (add_hintdevice(hint_new, ast_get_extension_app(e))) {
      ast_log(LOG_WARNING, "Could not add devices for hint: %s@%s.\n",
         ast_get_extension_name(e),
         ast_get_context_name(ast_get_extension_context(e)));
   }

   ao2_unlock(hints);
   ao2_ref(hint_new, -1);

   return 0;
}

/*! \brief Change hint for an extension */
static int ast_change_hint(struct ast_exten *oe, struct ast_exten *ne)
{
   struct ast_hint *hint;

   if (!oe || !ne) {
      return -1;
   }

   ao2_lock(hints);/* Locked to hold off others while we move the hint around. */

   /*
    * Unlink the hint from the hints container as the extension
    * name (which is the hash value) could change.
    */
   hint = ao2_find(hints, oe, OBJ_UNLINK);
   if (!hint) {
      ao2_unlock(hints);
      return -1;
   }

   remove_hintdevice(hint);

   /* Update the hint and put it back in the hints container. */
   ao2_lock(hint);
   hint->exten = ne;
   ao2_unlock(hint);
   ao2_link(hints, hint);
   if (add_hintdevice(hint, ast_get_extension_app(ne))) {
      ast_log(LOG_WARNING, "Could not add devices for hint: %s@%s.\n",
         ast_get_extension_name(ne),
         ast_get_context_name(ast_get_extension_context(ne)));
   }

   ao2_unlock(hints);
   ao2_ref(hint, -1);

   return 0;
}


/*! \brief Get hint for channel */
int ast_get_hint(char *hint, int hintsize, char *name, int namesize, struct ast_channel *c, const char *context, const char *exten)
{
   struct ast_exten *e = ast_hint_extension(c, context, exten);

   if (e) {
      if (hint)
         ast_copy_string(hint, ast_get_extension_app(e), hintsize);
      if (name) {
         const char *tmp = ast_get_extension_app_data(e);
         if (tmp)
            ast_copy_string(name, tmp, namesize);
      }
      return -1;
   }
   return 0;
}

/*! \brief Get hint for channel */
int ast_str_get_hint(struct ast_str **hint, ssize_t hintsize, struct ast_str **name, ssize_t namesize, struct ast_channel *c, const char *context, const char *exten)
{
   struct ast_exten *e = ast_hint_extension(c, context, exten);

   if (!e) {
      return 0;
   }

   if (hint) {
      ast_str_set(hint, hintsize, "%s", ast_get_extension_app(e));
   }
   if (name) {
      const char *tmp = ast_get_extension_app_data(e);
      if (tmp) {
         ast_str_set(name, namesize, "%s", tmp);
      }
   }
   return -1;
}

int ast_exists_extension(struct ast_channel *c, const char *context, const char *exten, int priority, const char *callerid)
{
   return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, E_MATCH, 0, 0);
}

int ast_findlabel_extension(struct ast_channel *c, const char *context, const char *exten, const char *label, const char *callerid)
{
   return pbx_extension_helper(c, NULL, context, exten, 0, label, callerid, E_FINDLABEL, 0, 0);
}

int ast_findlabel_extension2(struct ast_channel *c, struct ast_context *con, const char *exten, const char *label, const char *callerid)
{
   return pbx_extension_helper(c, con, NULL, exten, 0, label, callerid, E_FINDLABEL, 0, 0);
}

int ast_canmatch_extension(struct ast_channel *c, const char *context, const char *exten, int priority, const char *callerid)
{
   return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, E_CANMATCH, 0, 0);
}

int ast_matchmore_extension(struct ast_channel *c, const char *context, const char *exten, int priority, const char *callerid)
{
   return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, E_MATCHMORE, 0, 0);
}

int ast_spawn_extension(struct ast_channel *c, const char *context, const char *exten, int priority, const char *callerid, int *found, int combined_find_spawn)
{
   return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, E_SPAWN, found, combined_find_spawn);
}

void ast_pbx_h_exten_run(struct ast_channel *chan, const char *context)
{
   int autoloopflag;
   int found;
   int spawn_error;

   ast_channel_lock(chan);

   if (ast_channel_cdr(chan) && ast_opt_end_cdr_before_h_exten) {
      ast_cdr_end(ast_channel_cdr(chan));
   }

   /* Set h exten location */
   if (context != ast_channel_context(chan)) {
      ast_channel_context_set(chan, context);
   }
   ast_channel_exten_set(chan, "h");
   ast_channel_priority_set(chan, 1);

   /*
    * Make sure that the channel is marked as hungup since we are
    * going to run the h exten on it.
    */
   ast_softhangup_nolock(chan, AST_SOFTHANGUP_APPUNLOAD);

   /* Save autoloop flag */
   autoloopflag = ast_test_flag(ast_channel_flags(chan), AST_FLAG_IN_AUTOLOOP);
   ast_set_flag(ast_channel_flags(chan), AST_FLAG_IN_AUTOLOOP);
   ast_channel_unlock(chan);

   for (;;) {
      spawn_error = ast_spawn_extension(chan, ast_channel_context(chan),
         ast_channel_exten(chan), ast_channel_priority(chan),
         S_COR(ast_channel_caller(chan)->id.number.valid,
            ast_channel_caller(chan)->id.number.str, NULL), &found, 1);

      ast_channel_lock(chan);
      if (spawn_error) {
         /* The code after the loop needs the channel locked. */
         break;
      }
      ast_channel_priority_set(chan, ast_channel_priority(chan) + 1);
      ast_channel_unlock(chan);
   }
   if (found && spawn_error) {
      /* Something bad happened, or a hangup has been requested. */
      ast_debug(1, "Spawn extension (%s,%s,%d) exited non-zero on '%s'\n",
         ast_channel_context(chan), ast_channel_exten(chan),
         ast_channel_priority(chan), ast_channel_name(chan));
      ast_verb(2, "Spawn extension (%s, %s, %d) exited non-zero on '%s'\n",
         ast_channel_context(chan), ast_channel_exten(chan),
         ast_channel_priority(chan), ast_channel_name(chan));
   }

   /* An "h" exten has been run, so indicate that one has been run. */
   ast_set_flag(ast_channel_flags(chan), AST_FLAG_BRIDGE_HANGUP_RUN);

   /* Restore autoloop flag */
   ast_set2_flag(ast_channel_flags(chan), autoloopflag, AST_FLAG_IN_AUTOLOOP);
   ast_channel_unlock(chan);
}

int ast_pbx_hangup_handler_run(struct ast_channel *chan)
{
   struct ast_hangup_handler_list *handlers;
   struct ast_hangup_handler *h_handler;

   ast_channel_lock(chan);
   handlers = ast_channel_hangup_handlers(chan);
   if (AST_LIST_EMPTY(handlers)) {
      ast_channel_unlock(chan);
      return 0;
   }

   if (ast_channel_cdr(chan) && ast_opt_end_cdr_before_h_exten) {
      ast_cdr_end(ast_channel_cdr(chan));
   }

   /*
    * Make sure that the channel is marked as hungup since we are
    * going to run the hangup handlers on it.
    */
   ast_softhangup_nolock(chan, AST_SOFTHANGUP_APPUNLOAD);

   for (;;) {
      handlers = ast_channel_hangup_handlers(chan);
      h_handler = AST_LIST_REMOVE_HEAD(handlers, node);
      if (!h_handler) {
         break;
      }

      /*** DOCUMENTATION
         <managerEventInstance>
            <synopsis>Raised when a hangup handler is about to be called.</synopsis>
            <syntax>
               <parameter name="Handler">
                  <para>Hangup handler parameter string passed to the Gosub application.</para>
               </parameter>
            </syntax>
         </managerEventInstance>
      ***/
      manager_event(EVENT_FLAG_DIALPLAN, "HangupHandlerRun",
         "Channel: %s\r\n"
         "Uniqueid: %s\r\n"
         "Handler: %s\r\n",
         ast_channel_name(chan),
         ast_channel_uniqueid(chan),
         h_handler->args);
      ast_channel_unlock(chan);

      ast_app_exec_sub(NULL, chan, h_handler->args, 1);
      ast_free(h_handler);

      ast_channel_lock(chan);
   }
   ast_channel_unlock(chan);
   return 1;
}

void ast_pbx_hangup_handler_init(struct ast_channel *chan)
{
   struct ast_hangup_handler_list *handlers;

   handlers = ast_channel_hangup_handlers(chan);
   AST_LIST_HEAD_INIT_NOLOCK(handlers);
}

void ast_pbx_hangup_handler_destroy(struct ast_channel *chan)
{
   struct ast_hangup_handler_list *handlers;
   struct ast_hangup_handler *h_handler;

   ast_channel_lock(chan);

   /* Get rid of each of the hangup handlers on the channel */
   handlers = ast_channel_hangup_handlers(chan);
   while ((h_handler = AST_LIST_REMOVE_HEAD(handlers, node))) {
      ast_free(h_handler);
   }

   ast_channel_unlock(chan);
}

int ast_pbx_hangup_handler_pop(struct ast_channel *chan)
{
   struct ast_hangup_handler_list *handlers;
   struct ast_hangup_handler *h_handler;

   ast_channel_lock(chan);
   handlers = ast_channel_hangup_handlers(chan);
   h_handler = AST_LIST_REMOVE_HEAD(handlers, node);
   if (h_handler) {
      /*** DOCUMENTATION
         <managerEventInstance>
            <synopsis>
               Raised when a hangup handler is removed from the handler
               stack by the CHANNEL() function.
            </synopsis>
            <syntax>
               <parameter name="Handler">
                  <para>Hangup handler parameter string passed to the Gosub application.</para>
               </parameter>
            </syntax>
            <see-also>
               <ref type="managerEvent">HangupHandlerPush</ref>
               <ref type="function">CHANNEL</ref>
            </see-also>
         </managerEventInstance>
      ***/
      manager_event(EVENT_FLAG_DIALPLAN, "HangupHandlerPop",
         "Channel: %s\r\n"
         "Uniqueid: %s\r\n"
         "Handler: %s\r\n",
         ast_channel_name(chan),
         ast_channel_uniqueid(chan),
         h_handler->args);
   }
   ast_channel_unlock(chan);
   if (h_handler) {
      ast_free(h_handler);
      return 1;
   }
   return 0;
}

void ast_pbx_hangup_handler_push(struct ast_channel *chan, const char *handler)
{
   struct ast_hangup_handler_list *handlers;
   struct ast_hangup_handler *h_handler;
   const char *expanded_handler;

   if (ast_strlen_zero(handler)) {
      return;
   }

   expanded_handler = ast_app_expand_sub_args(chan, handler);
   if (!expanded_handler) {
      return;
   }
   h_handler = ast_malloc(sizeof(*h_handler) + 1 + strlen(expanded_handler));
   if (!h_handler) {
      ast_free((char *) expanded_handler);
      return;
   }
   strcpy(h_handler->args, expanded_handler);/* Safe */
   ast_free((char *) expanded_handler);

   ast_channel_lock(chan);

   handlers = ast_channel_hangup_handlers(chan);
   AST_LIST_INSERT_HEAD(handlers, h_handler, node);

   /*** DOCUMENTATION
      <managerEventInstance>
         <synopsis>
            Raised when a hangup handler is added to the handler
            stack by the CHANNEL() function.
         </synopsis>
         <syntax>
            <parameter name="Handler">
               <para>Hangup handler parameter string passed to the Gosub application.</para>
            </parameter>
         </syntax>
         <see-also>
            <ref type="managerEvent">HangupHandlerPop</ref>
            <ref type="function">CHANNEL</ref>
         </see-also>
      </managerEventInstance>
   ***/
   manager_event(EVENT_FLAG_DIALPLAN, "HangupHandlerPush",
      "Channel: %s\r\n"
      "Uniqueid: %s\r\n"
      "Handler: %s\r\n",
      ast_channel_name(chan),
      ast_channel_uniqueid(chan),
      h_handler->args);

   ast_channel_unlock(chan);
}

#define HANDLER_FORMAT  "%-30s %s\n"

/*!
 * \internal
 * \brief CLI output the hangup handler headers.
 * \since 11.0
 *
 * \param fd CLI file descriptor to use.
 *
 * \return Nothing
 */
static void ast_pbx_hangup_handler_headers(int fd)
{
   ast_cli(fd, HANDLER_FORMAT, "Channel", "Handler");
}

/*!
 * \internal
 * \brief CLI output the channel hangup handlers.
 * \since 11.0
 *
 * \param fd CLI file descriptor to use.
 * \param chan Channel to show hangup handlers.
 *
 * \return Nothing
 */
static void ast_pbx_hangup_handler_show(int fd, struct ast_channel *chan)
{
   struct ast_hangup_handler_list *handlers;
   struct ast_hangup_handler *h_handler;
   int first = 1;

   ast_channel_lock(chan);
   handlers = ast_channel_hangup_handlers(chan);
   AST_LIST_TRAVERSE(handlers, h_handler, node) {
      ast_cli(fd, HANDLER_FORMAT, first ? ast_channel_name(chan) : "", h_handler->args);
      first = 0;
   }
   ast_channel_unlock(chan);
}

/*
 * \brief 'show hanguphandlers <channel>' CLI command implementation function...
 */
static char *handle_show_hangup_channel(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct ast_channel *chan;

   switch (cmd) {
   case CLI_INIT:
      e->command = "core show hanguphandlers";
      e->usage =
         "Usage: core show hanguphandlers <channel>\n"
         "       Show hangup handlers of a specified channel.\n";
      return NULL;
   case CLI_GENERATE:
      return ast_complete_channels(a->line, a->word, a->pos, a->n, e->args);
   }

   if (a->argc < 4) {
      return CLI_SHOWUSAGE;
   }

   chan = ast_channel_get_by_name(a->argv[3]);
   if (!chan) {
      ast_cli(a->fd, "Channel does not exist.\n");
      return CLI_FAILURE;
   }

   ast_pbx_hangup_handler_headers(a->fd);
   ast_pbx_hangup_handler_show(a->fd, chan);

   ast_channel_unref(chan);

   return CLI_SUCCESS;
}

/*
 * \brief 'show hanguphandlers all' CLI command implementation function...
 */
static char *handle_show_hangup_all(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct ast_channel_iterator *iter;
   struct ast_channel *chan;

   switch (cmd) {
   case CLI_INIT:
      e->command = "core show hanguphandlers all";
      e->usage =
         "Usage: core show hanguphandlers all\n"
         "       Show hangup handlers for all channels.\n";
      return NULL;
   case CLI_GENERATE:
      return ast_complete_channels(a->line, a->word, a->pos, a->n, e->args);
   }

   if (a->argc < 4) {
      return CLI_SHOWUSAGE;
   }

   iter = ast_channel_iterator_all_new();
   if (!iter) {
      return CLI_FAILURE;
   }

   ast_pbx_hangup_handler_headers(a->fd);
   for (; (chan = ast_channel_iterator_next(iter)); ast_channel_unref(chan)) {
      ast_pbx_hangup_handler_show(a->fd, chan);
   }
   ast_channel_iterator_destroy(iter);

   return CLI_SUCCESS;
}

/*! helper function to set extension and priority */
static void set_ext_pri(struct ast_channel *c, const char *exten, int pri)
{
   ast_channel_lock(c);
   ast_channel_exten_set(c, exten);
   ast_channel_priority_set(c, pri);
   ast_channel_unlock(c);
}

/*!
 * \brief collect digits from the channel into the buffer.
 * \param c, buf, buflen, pos
 * \param waittime is in milliseconds
 * \retval 0 on timeout or done.
 * \retval -1 on error.
*/
static int collect_digits(struct ast_channel *c, int waittime, char *buf, int buflen, int pos)
{
   int digit;

   buf[pos] = '\0';  /* make sure it is properly terminated */
   while (ast_matchmore_extension(c, ast_channel_context(c), buf, 1,
      S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
      /* As long as we're willing to wait, and as long as it's not defined,
         keep reading digits until we can't possibly get a right answer anymore.  */
      digit = ast_waitfordigit(c, waittime);
      if (ast_channel_softhangup_internal_flag(c) & AST_SOFTHANGUP_ASYNCGOTO) {
         ast_channel_clear_softhangup(c, AST_SOFTHANGUP_ASYNCGOTO);
      } else {
         if (!digit) /* No entry */
            break;
         if (digit < 0) /* Error, maybe a  hangup */
            return -1;
         if (pos < buflen - 1) { /* XXX maybe error otherwise ? */
            buf[pos++] = digit;
            buf[pos] = '\0';
         }
         waittime = ast_channel_pbx(c)->dtimeoutms;
      }
   }
   return 0;
}

static enum ast_pbx_result __ast_pbx_run(struct ast_channel *c,
      struct ast_pbx_args *args)
{
   int found = 0; /* set if we find at least one match */
   int res = 0;
   int autoloopflag;
   int error = 0;    /* set an error conditions */
   struct ast_pbx *pbx;
   struct ast_callid *callid;

   /* A little initial setup here */
   if (ast_channel_pbx(c)) {
      ast_log(LOG_WARNING, "%s already has PBX structure??\n", ast_channel_name(c));
      /* XXX and now what ? */
      ast_free(ast_channel_pbx(c));
   }
   if (!(pbx = ast_calloc(1, sizeof(*pbx)))) {
      return -1;
   }

   callid = ast_read_threadstorage_callid();
   /* If the thread isn't already associated with a callid, we should create that association. */
   if (!callid) {
      /* Associate new PBX thread with the channel call id if it is availble.
       * If not, create a new one instead.
       */
      callid = ast_channel_callid(c);
      if (!callid) {
         callid = ast_create_callid();
         if (callid) {
            ast_channel_callid_set(c, callid);
         }
      }
      ast_callid_threadassoc_add(callid);
      callid = ast_callid_unref(callid);
   } else {
      /* Nothing to do here, The thread is already bound to a callid.  Let's just get rid of the reference. */
      ast_callid_unref(callid);
   }

   ast_channel_pbx_set(c, pbx);
   /* Set reasonable defaults */
   ast_channel_pbx(c)->rtimeoutms = 10000;
   ast_channel_pbx(c)->dtimeoutms = 5000;

   autoloopflag = ast_test_flag(ast_channel_flags(c), AST_FLAG_IN_AUTOLOOP);  /* save value to restore at the end */
   ast_set_flag(ast_channel_flags(c), AST_FLAG_IN_AUTOLOOP);

   if (ast_strlen_zero(ast_channel_exten(c))) {
      /* If not successful fall back to 's' - but only if there is no given exten  */
      ast_verb(2, "Starting %s at %s,%s,%d failed so falling back to exten 's'\n", ast_channel_name(c), ast_channel_context(c), ast_channel_exten(c), ast_channel_priority(c));
      /* XXX the original code used the existing priority in the call to
       * ast_exists_extension(), and reset it to 1 afterwards.
       * I believe the correct thing is to set it to 1 immediately.
      */
      set_ext_pri(c, "s", 1);
   }

   ast_channel_lock(c);
   if (ast_channel_cdr(c)) {
      /* allow CDR variables that have been collected after channel was created to be visible during call */
      ast_cdr_update(c);
   }
   ast_channel_unlock(c);
   for (;;) {
      char dst_exten[256]; /* buffer to accumulate digits */
      int pos = 0;      /* XXX should check bounds */
      int digit = 0;
      int invalid = 0;
      int timeout = 0;

      /* No digits pressed yet */
      dst_exten[pos] = '\0';

      /* loop on priorities in this context/exten */
      while (!(res = ast_spawn_extension(c, ast_channel_context(c), ast_channel_exten(c), ast_channel_priority(c),
         S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL),
         &found, 1))) {
         if (!ast_check_hangup(c)) {
            ast_channel_priority_set(c, ast_channel_priority(c) + 1);
            continue;
         }

         /* Check softhangup flags. */
         if (ast_channel_softhangup_internal_flag(c) & AST_SOFTHANGUP_ASYNCGOTO) {
            ast_channel_clear_softhangup(c, AST_SOFTHANGUP_ASYNCGOTO);
            continue;
         }
         if (ast_channel_softhangup_internal_flag(c) & AST_SOFTHANGUP_TIMEOUT) {
            if (ast_exists_extension(c, ast_channel_context(c), "T", 1,
               S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
               set_ext_pri(c, "T", 1);
               /* If the AbsoluteTimeout is not reset to 0, we'll get an infinite loop */
               memset(ast_channel_whentohangup(c), 0, sizeof(*ast_channel_whentohangup(c)));
               ast_channel_clear_softhangup(c, AST_SOFTHANGUP_TIMEOUT);
               continue;
            } else if (ast_exists_extension(c, ast_channel_context(c), "e", 1,
               S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
               raise_exception(c, "ABSOLUTETIMEOUT", 1);
               /* If the AbsoluteTimeout is not reset to 0, we'll get an infinite loop */
               memset(ast_channel_whentohangup(c), 0, sizeof(*ast_channel_whentohangup(c)));
               ast_channel_clear_softhangup(c, AST_SOFTHANGUP_TIMEOUT);
               continue;
            }

            /* Call timed out with no special extension to jump to. */
            error = 1;
            break;
         }
         ast_debug(1, "Extension %s, priority %d returned normally even though call was hung up\n",
            ast_channel_exten(c), ast_channel_priority(c));
         error = 1;
         break;
      } /* end while  - from here on we can use 'break' to go out */
      if (found && res) {
         /* Something bad happened, or a hangup has been requested. */
         if (strchr("0123456789ABCDEF*#", res)) {
            ast_debug(1, "Oooh, got something to jump out with ('%c')!\n", res);
            pos = 0;
            dst_exten[pos++] = digit = res;
            dst_exten[pos] = '\0';
         } else if (res == AST_PBX_INCOMPLETE) {
            ast_debug(1, "Spawn extension (%s,%s,%d) exited INCOMPLETE on '%s'\n", ast_channel_context(c), ast_channel_exten(c), ast_channel_priority(c), ast_channel_name(c));
            ast_verb(2, "Spawn extension (%s, %s, %d) exited INCOMPLETE on '%s'\n", ast_channel_context(c), ast_channel_exten(c), ast_channel_priority(c), ast_channel_name(c));

            /* Don't cycle on incomplete - this will happen if the only extension that matches is our "incomplete" extension */
            if (!ast_matchmore_extension(c, ast_channel_context(c), ast_channel_exten(c), 1,
               S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
               invalid = 1;
            } else {
               ast_copy_string(dst_exten, ast_channel_exten(c), sizeof(dst_exten));
               digit = 1;
               pos = strlen(dst_exten);
            }
         } else {
            ast_debug(1, "Spawn extension (%s,%s,%d) exited non-zero on '%s'\n", ast_channel_context(c), ast_channel_exten(c), ast_channel_priority(c), ast_channel_name(c));
            ast_verb(2, "Spawn extension (%s, %s, %d) exited non-zero on '%s'\n", ast_channel_context(c), ast_channel_exten(c), ast_channel_priority(c), ast_channel_name(c));

            if ((res == AST_PBX_ERROR)
               && ast_exists_extension(c, ast_channel_context(c), "e", 1,
                  S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
               /* if we are already on the 'e' exten, don't jump to it again */
               if (!strcmp(ast_channel_exten(c), "e")) {
                  ast_verb(2, "Spawn extension (%s, %s, %d) exited ERROR while already on 'e' exten on '%s'\n", ast_channel_context(c), ast_channel_exten(c), ast_channel_priority(c), ast_channel_name(c));
                  error = 1;
               } else {
                  raise_exception(c, "ERROR", 1);
                  continue;
               }
            }

            if (ast_channel_softhangup_internal_flag(c) & AST_SOFTHANGUP_ASYNCGOTO) {
               ast_channel_clear_softhangup(c, AST_SOFTHANGUP_ASYNCGOTO);
               continue;
            }
            if (ast_channel_softhangup_internal_flag(c) & AST_SOFTHANGUP_TIMEOUT) {
               if (ast_exists_extension(c, ast_channel_context(c), "T", 1,
                  S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
                  set_ext_pri(c, "T", 1);
                  /* If the AbsoluteTimeout is not reset to 0, we'll get an infinite loop */
                  memset(ast_channel_whentohangup(c), 0, sizeof(*ast_channel_whentohangup(c)));
                  ast_channel_clear_softhangup(c, AST_SOFTHANGUP_TIMEOUT);
                  continue;
               } else if (ast_exists_extension(c, ast_channel_context(c), "e", 1,
                  S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
                  raise_exception(c, "ABSOLUTETIMEOUT", 1);
                  /* If the AbsoluteTimeout is not reset to 0, we'll get an infinite loop */
                  memset(ast_channel_whentohangup(c), 0, sizeof(*ast_channel_whentohangup(c)));
                  ast_channel_clear_softhangup(c, AST_SOFTHANGUP_TIMEOUT);
                  continue;
               }
               /* Call timed out with no special extension to jump to. */
            }
            ast_channel_lock(c);
            if (ast_channel_cdr(c)) {
               ast_cdr_update(c);
            }
            ast_channel_unlock(c);
            error = 1;
            break;
         }
      }
      if (error)
         break;

      /*!\note
       * We get here on a failure of some kind:  non-existing extension or
       * hangup.  We have options, here.  We can either catch the failure
       * and continue, or we can drop out entirely. */

      if (invalid
         || (ast_strlen_zero(dst_exten) &&
            !ast_exists_extension(c, ast_channel_context(c), ast_channel_exten(c), 1,
            S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL)))) {
         /*!\note
          * If there is no match at priority 1, it is not a valid extension anymore.
          * Try to continue at "i" (for invalid) or "e" (for exception) or exit if
          * neither exist.
          */
         if (ast_exists_extension(c, ast_channel_context(c), "i", 1,
            S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
            ast_verb(3, "Channel '%s' sent to invalid extension: context,exten,priority=%s,%s,%d\n",
               ast_channel_name(c), ast_channel_context(c), ast_channel_exten(c), ast_channel_priority(c));
            pbx_builtin_setvar_helper(c, "INVALID_EXTEN", ast_channel_exten(c));
            set_ext_pri(c, "i", 1);
         } else if (ast_exists_extension(c, ast_channel_context(c), "e", 1,
            S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
            raise_exception(c, "INVALID", 1);
         } else {
            ast_log(LOG_WARNING, "Channel '%s' sent to invalid extension but no invalid handler: context,exten,priority=%s,%s,%d\n",
               ast_channel_name(c), ast_channel_context(c), ast_channel_exten(c), ast_channel_priority(c));
            error = 1; /* we know what to do with it */
            break;
         }
      } else if (ast_channel_softhangup_internal_flag(c) & AST_SOFTHANGUP_TIMEOUT) {
         /* If we get this far with AST_SOFTHANGUP_TIMEOUT, then we know that the "T" extension is next. */
         ast_channel_clear_softhangup(c, AST_SOFTHANGUP_TIMEOUT);
      } else { /* keypress received, get more digits for a full extension */
         int waittime = 0;
         if (digit)
            waittime = ast_channel_pbx(c)->dtimeoutms;
         else if (!autofallthrough)
            waittime = ast_channel_pbx(c)->rtimeoutms;
         if (!waittime) {
            const char *status = pbx_builtin_getvar_helper(c, "DIALSTATUS");
            if (!status)
               status = "UNKNOWN";
            ast_verb(3, "Auto fallthrough, channel '%s' status is '%s'\n", ast_channel_name(c), status);
            if (!strcasecmp(status, "CONGESTION"))
               res = pbx_builtin_congestion(c, "10");
            else if (!strcasecmp(status, "CHANUNAVAIL"))
               res = pbx_builtin_congestion(c, "10");
            else if (!strcasecmp(status, "BUSY"))
               res = pbx_builtin_busy(c, "10");
            error = 1; /* XXX disable message */
            break;   /* exit from the 'for' loop */
         }

         if (collect_digits(c, waittime, dst_exten, sizeof(dst_exten), pos))
            break;
         if (res == AST_PBX_INCOMPLETE && ast_strlen_zero(&dst_exten[pos]))
            timeout = 1;
         if (!timeout
            && ast_exists_extension(c, ast_channel_context(c), dst_exten, 1,
               S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) { /* Prepare the next cycle */
            set_ext_pri(c, dst_exten, 1);
         } else {
            /* No such extension */
            if (!timeout && !ast_strlen_zero(dst_exten)) {
               /* An invalid extension */
               if (ast_exists_extension(c, ast_channel_context(c), "i", 1,
                  S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
                  ast_verb(3, "Invalid extension '%s' in context '%s' on %s\n", dst_exten, ast_channel_context(c), ast_channel_name(c));
                  pbx_builtin_setvar_helper(c, "INVALID_EXTEN", dst_exten);
                  set_ext_pri(c, "i", 1);
               } else if (ast_exists_extension(c, ast_channel_context(c), "e", 1,
                  S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
                  raise_exception(c, "INVALID", 1);
               } else {
                  ast_log(LOG_WARNING,
                     "Invalid extension '%s', but no rule 'i' or 'e' in context '%s'\n",
                     dst_exten, ast_channel_context(c));
                  found = 1; /* XXX disable message */
                  break;
               }
            } else {
               /* A simple timeout */
               if (ast_exists_extension(c, ast_channel_context(c), "t", 1,
                  S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
                  ast_verb(3, "Timeout on %s\n", ast_channel_name(c));
                  set_ext_pri(c, "t", 1);
               } else if (ast_exists_extension(c, ast_channel_context(c), "e", 1,
                  S_COR(ast_channel_caller(c)->id.number.valid, ast_channel_caller(c)->id.number.str, NULL))) {
                  raise_exception(c, "RESPONSETIMEOUT", 1);
               } else {
                  ast_log(LOG_WARNING,
                     "Timeout, but no rule 't' or 'e' in context '%s'\n",
                     ast_channel_context(c));
                  found = 1; /* XXX disable message */
                  break;
               }
            }
         }
         ast_channel_lock(c);
         if (ast_channel_cdr(c)) {
            ast_verb(2, "CDR updated on %s\n",ast_channel_name(c));
            ast_cdr_update(c);
         }
         ast_channel_unlock(c);
      }
   }

   if (!found && !error) {
      ast_log(LOG_WARNING, "Don't know what to do with '%s'\n", ast_channel_name(c));
   }

   if (!args || !args->no_hangup_chan) {
      ast_softhangup(c, AST_SOFTHANGUP_APPUNLOAD);
      if (!ast_test_flag(ast_channel_flags(c), AST_FLAG_BRIDGE_HANGUP_RUN)
         && ast_exists_extension(c, ast_channel_context(c), "h", 1,
            S_COR(ast_channel_caller(c)->id.number.valid,
               ast_channel_caller(c)->id.number.str, NULL))) {
         ast_pbx_h_exten_run(c, ast_channel_context(c));
      }
      ast_pbx_hangup_handler_run(c);
   }

   ast_set2_flag(ast_channel_flags(c), autoloopflag, AST_FLAG_IN_AUTOLOOP);
   ast_clear_flag(ast_channel_flags(c), AST_FLAG_BRIDGE_HANGUP_RUN); /* from one round to the next, make sure this gets cleared */
   pbx_destroy(ast_channel_pbx(c));
   ast_channel_pbx_set(c, NULL);

   if (!args || !args->no_hangup_chan) {
      ast_hangup(c);
   }

   return 0;
}

/*!
 * \brief Increase call count for channel
 * \retval 0 on success
 * \retval non-zero if a configured limit (maxcalls, maxload, minmemfree) was reached
*/
static int increase_call_count(const struct ast_channel *c)
{
   int failed = 0;
   double curloadavg;
#if defined(HAVE_SYSINFO)
   long curfreemem;
   struct sysinfo sys_info;
#endif

   ast_mutex_lock(&maxcalllock);
   if (option_maxcalls) {
      if (countcalls >= option_maxcalls) {
         ast_log(LOG_WARNING, "Maximum call limit of %d calls exceeded by '%s'!\n", option_maxcalls, ast_channel_name(c));
         failed = -1;
      }
   }
   if (option_maxload) {
      getloadavg(&curloadavg, 1);
      if (curloadavg >= option_maxload) {
         ast_log(LOG_WARNING, "Maximum loadavg limit of %f load exceeded by '%s' (currently %f)!\n", option_maxload, ast_channel_name(c), curloadavg);
         failed = -1;
      }
   }
#if defined(HAVE_SYSINFO)
   if (option_minmemfree) {
      if (!sysinfo(&sys_info)) {
         /* make sure that the free system memory is above the configured low watermark
          * convert the amount of freeram from mem_units to MB */
         curfreemem = sys_info.freeram * sys_info.mem_unit;
         curfreemem /= 1024 * 1024;
         if (curfreemem < option_minmemfree) {
            ast_log(LOG_WARNING, "Available system memory (~%ldMB) is below the configured low watermark (%ldMB)\n", curfreemem, option_minmemfree);
            failed = -1;
         }
      }
   }
#endif

   if (!failed) {
      countcalls++;
      totalcalls++;
   }
   ast_mutex_unlock(&maxcalllock);

   return failed;
}

static void decrease_call_count(void)
{
   ast_mutex_lock(&maxcalllock);
   if (countcalls > 0)
      countcalls--;
   ast_mutex_unlock(&maxcalllock);
}

static void destroy_exten(struct ast_exten *e)
{
   if (e->priority == PRIORITY_HINT)
      ast_remove_hint(e);

   if (e->peer_table)
      ast_hashtab_destroy(e->peer_table,0);
   if (e->peer_label_table)
      ast_hashtab_destroy(e->peer_label_table, 0);
   if (e->datad)
      e->datad(e->data);
   ast_free(e);
}

static void *pbx_thread(void *data)
{
   /* Oh joyeous kernel, we're a new thread, with nothing to do but
      answer this channel and get it going.
   */
   /* NOTE:
      The launcher of this function _MUST_ increment 'countcalls'
      before invoking the function; it will be decremented when the
      PBX has finished running on the channel
    */
   struct ast_channel *c = data;

   __ast_pbx_run(c, NULL);
   decrease_call_count();

   pthread_exit(NULL);

   return NULL;
}

enum ast_pbx_result ast_pbx_start(struct ast_channel *c)
{
   pthread_t t;

   if (!c) {
      ast_log(LOG_WARNING, "Asked to start thread on NULL channel?\n");
      return AST_PBX_FAILED;
   }

   if (!ast_test_flag(&ast_options, AST_OPT_FLAG_FULLY_BOOTED)) {
      ast_log(LOG_WARNING, "PBX requires Asterisk to be fully booted\n");
      return AST_PBX_FAILED;
   }

   if (increase_call_count(c))
      return AST_PBX_CALL_LIMIT;

   /* Start a new thread, and get something handling this channel. */
   if (ast_pthread_create_detached(&t, NULL, pbx_thread, c)) {
      ast_log(LOG_WARNING, "Failed to create new channel thread\n");
      decrease_call_count();
      return AST_PBX_FAILED;
   }

   return AST_PBX_SUCCESS;
}

enum ast_pbx_result ast_pbx_run_args(struct ast_channel *c, struct ast_pbx_args *args)
{
   enum ast_pbx_result res = AST_PBX_SUCCESS;

   if (!ast_test_flag(&ast_options, AST_OPT_FLAG_FULLY_BOOTED)) {
      ast_log(LOG_WARNING, "PBX requires Asterisk to be fully booted\n");
      return AST_PBX_FAILED;
   }

   if (increase_call_count(c)) {
      return AST_PBX_CALL_LIMIT;
   }

   res = __ast_pbx_run(c, args);

   decrease_call_count();

   return res;
}

enum ast_pbx_result ast_pbx_run(struct ast_channel *c)
{
   return ast_pbx_run_args(c, NULL);
}

int ast_active_calls(void)
{
   return countcalls;
}

int ast_processed_calls(void)
{
   return totalcalls;
}

int pbx_set_autofallthrough(int newval)
{
   int oldval = autofallthrough;
   autofallthrough = newval;
   return oldval;
}

int pbx_set_extenpatternmatchnew(int newval)
{
   int oldval = extenpatternmatchnew;
   extenpatternmatchnew = newval;
   return oldval;
}

void pbx_set_overrideswitch(const char *newval)
{
   if (overrideswitch) {
      ast_free(overrideswitch);
   }
   if (!ast_strlen_zero(newval)) {
      overrideswitch = ast_strdup(newval);
   } else {
      overrideswitch = NULL;
   }
}

/*!
 * \brief lookup for a context with a given name,
 * \retval found context or NULL if not found.
 */
static struct ast_context *find_context(const char *context)
{
   struct fake_context item;

   ast_copy_string(item.name, context, sizeof(item.name));

   return ast_hashtab_lookup(contexts_table, &item);
}

/*!
 * \brief lookup for a context with a given name,
 * \retval with conlock held if found.
 * \retval NULL if not found.
 */
static struct ast_context *find_context_locked(const char *context)
{
   struct ast_context *c;
   struct fake_context item;

   ast_copy_string(item.name, context, sizeof(item.name));

   ast_rdlock_contexts();
   c = ast_hashtab_lookup(contexts_table, &item);
   if (!c) {
      ast_unlock_contexts();
   }

   return c;
}

/*!
 * \brief Remove included contexts.
 * This function locks contexts list by &conlist, search for the right context
 * structure, leave context list locked and call ast_context_remove_include2
 * which removes include, unlock contexts list and return ...
 */
int ast_context_remove_include(const char *context, const char *include, const char *registrar)
{
   int ret = -1;
   struct ast_context *c;

   c = find_context_locked(context);
   if (c) {
      /* found, remove include from this context ... */
      ret = ast_context_remove_include2(c, include, registrar);
      ast_unlock_contexts();
   }
   return ret;
}

/*!
 * \brief Locks context, remove included contexts, unlocks context.
 * When we call this function, &conlock lock must be locked, because when
 * we giving *con argument, some process can remove/change this context
 * and after that there can be segfault.
 *
 * \retval 0 on success.
 * \retval -1 on failure.
 */
int ast_context_remove_include2(struct ast_context *con, const char *include, const char *registrar)
{
   struct ast_include *i, *pi = NULL;
   int ret = -1;

   ast_wrlock_context(con);

   /* find our include */
   for (i = con->includes; i; pi = i, i = i->next) {
      if (!strcmp(i->name, include) &&
            (!registrar || !strcmp(i->registrar, registrar))) {
         /* remove from list */
         ast_verb(3, "Removing inclusion of context '%s' in context '%s; registrar=%s'\n", include, ast_get_context_name(con), registrar);
         if (pi)
            pi->next = i->next;
         else
            con->includes = i->next;
         /* free include and return */
         ast_destroy_timing(&(i->timing));
         ast_free(i);
         ret = 0;
         break;
      }
   }

   ast_unlock_context(con);

   return ret;
}

/*!
 * \note This function locks contexts list by &conlist, search for the rigt context
 * structure, leave context list locked and call ast_context_remove_switch2
 * which removes switch, unlock contexts list and return ...
 */
int ast_context_remove_switch(const char *context, const char *sw, const char *data, const char *registrar)
{
   int ret = -1; /* default error return */
   struct ast_context *c;

   c = find_context_locked(context);
   if (c) {
      /* remove switch from this context ... */
      ret = ast_context_remove_switch2(c, sw, data, registrar);
      ast_unlock_contexts();
   }
   return ret;
}

/*!
 * \brief This function locks given context, removes switch, unlock context and
 * return.
 * \note When we call this function, &conlock lock must be locked, because when
 * we giving *con argument, some process can remove/change this context
 * and after that there can be segfault.
 *
 */
int ast_context_remove_switch2(struct ast_context *con, const char *sw, const char *data, const char *registrar)
{
   struct ast_sw *i;
   int ret = -1;

   ast_wrlock_context(con);

   /* walk switches */
   AST_LIST_TRAVERSE_SAFE_BEGIN(&con->alts, i, list) {
      if (!strcmp(i->name, sw) && !strcmp(i->data, data) &&
         (!registrar || !strcmp(i->registrar, registrar))) {
         /* found, remove from list */
         ast_verb(3, "Removing switch '%s' from context '%s; registrar=%s'\n", sw, ast_get_context_name(con), registrar);
         AST_LIST_REMOVE_CURRENT(list);
         ast_free(i); /* free switch and return */
         ret = 0;
         break;
      }
   }
   AST_LIST_TRAVERSE_SAFE_END;

   ast_unlock_context(con);

   return ret;
}

/*! \note This function will lock conlock. */
int ast_context_remove_extension(const char *context, const char *extension, int priority, const char *registrar)
{
   return ast_context_remove_extension_callerid(context, extension, priority, NULL, 0, registrar);
}

int ast_context_remove_extension_callerid(const char *context, const char *extension, int priority, const char *callerid, int matchcallerid, const char *registrar)
{
   int ret = -1; /* default error return */
   struct ast_context *c;

   c = find_context_locked(context);
   if (c) { /* ... remove extension ... */
      ret = ast_context_remove_extension_callerid2(c, extension, priority, callerid,
         matchcallerid, registrar, 0);
      ast_unlock_contexts();
   }

   return ret;
}

/*!
 * \brief This functionc locks given context, search for the right extension and
 * fires out all peer in this extensions with given priority. If priority
 * is set to 0, all peers are removed. After that, unlock context and
 * return.
 * \note When do you want to call this function, make sure that &conlock is locked,
 * because some process can handle with your *con context before you lock
 * it.
 *
 */
int ast_context_remove_extension2(struct ast_context *con, const char *extension, int priority, const char *registrar, int already_locked)
{
   return ast_context_remove_extension_callerid2(con, extension, priority, NULL, 0, registrar, already_locked);
}

int ast_context_remove_extension_callerid2(struct ast_context *con, const char *extension, int priority, const char *callerid, int matchcallerid, const char *registrar, int already_locked)
{
   struct ast_exten *exten, *prev_exten = NULL;
   struct ast_exten *peer;
   struct ast_exten ex, *exten2, *exten3;
   char dummy_name[1024];
   struct ast_exten *previous_peer = NULL;
   struct ast_exten *next_peer = NULL;
   int found = 0;

   if (!already_locked)
      ast_wrlock_context(con);

   /* Handle this is in the new world */

   /* FIXME For backwards compatibility, if callerid==NULL, then remove ALL
    * peers, not just those matching the callerid. */
#ifdef NEED_DEBUG
   ast_verb(3,"Removing %s/%s/%d%s%s from trees, registrar=%s\n", con->name, extension, priority, matchcallerid ? "/" : "", matchcallerid ? callerid : "", registrar);
#endif
#ifdef CONTEXT_DEBUG
   check_contexts(__FILE__, __LINE__);
#endif
   /* find this particular extension */
   ex.exten = dummy_name;
   ex.matchcid = matchcallerid && !ast_strlen_zero(callerid); /* don't say match if there's no callerid */
   ex.cidmatch = callerid;
   ast_copy_string(dummy_name, extension, sizeof(dummy_name));
   exten = ast_hashtab_lookup(con->root_table, &ex);
   if (exten) {
      if (priority == 0) {
         exten2 = ast_hashtab_remove_this_object(con->root_table, exten);
         if (!exten2)
            ast_log(LOG_ERROR,"Trying to delete the exten %s from context %s, but could not remove from the root_table\n", extension, con->name);
         if (con->pattern_tree) {
            struct match_char *x = add_exten_to_pattern_tree(con, exten, 1);

            if (x->exten) { /* this test for safety purposes */
               x->deleted = 1; /* with this marked as deleted, it will never show up in the scoreboard, and therefore never be found */
               x->exten = 0; /* get rid of what will become a bad pointer */
            } else {
               ast_log(LOG_WARNING,"Trying to delete an exten from a context, but the pattern tree node returned isn't a full extension\n");
            }
         }
      } else {
         ex.priority = priority;
         exten2 = ast_hashtab_lookup(exten->peer_table, &ex);
         if (exten2) {

            if (exten2->label) { /* if this exten has a label, remove that, too */
               exten3 = ast_hashtab_remove_this_object(exten->peer_label_table,exten2);
               if (!exten3)
                  ast_log(LOG_ERROR,"Did not remove this priority label (%d/%s) from the peer_label_table of context %s, extension %s!\n", priority, exten2->label, con->name, exten2->exten);
            }

            exten3 = ast_hashtab_remove_this_object(exten->peer_table, exten2);
            if (!exten3)
               ast_log(LOG_ERROR,"Did not remove this priority (%d) from the peer_table of context %s, extension %s!\n", priority, con->name, exten2->exten);
            if (exten2 == exten && exten2->peer) {
               exten2 = ast_hashtab_remove_this_object(con->root_table, exten);
               ast_hashtab_insert_immediate(con->root_table, exten2->peer);
            }
            if (ast_hashtab_size(exten->peer_table) == 0) {
               /* well, if the last priority of an exten is to be removed,
                  then, the extension is removed, too! */
               exten3 = ast_hashtab_remove_this_object(con->root_table, exten);
               if (!exten3)
                  ast_log(LOG_ERROR,"Did not remove this exten (%s) from the context root_table (%s) (priority %d)\n", exten->exten, con->name, priority);
               if (con->pattern_tree) {
                  struct match_char *x = add_exten_to_pattern_tree(con, exten, 1);
                  if (x->exten) { /* this test for safety purposes */
                     x->deleted = 1; /* with this marked as deleted, it will never show up in the scoreboard, and therefore never be found */
                     x->exten = 0; /* get rid of what will become a bad pointer */
                  }
               }
            }
         } else {
            ast_log(LOG_ERROR,"Could not find priority %d of exten %s in context %s!\n",
                  priority, exten->exten, con->name);
         }
      }
   } else {
      /* hmmm? this exten is not in this pattern tree? */
      ast_log(LOG_WARNING,"Cannot find extension %s in root_table in context %s\n",
            extension, con->name);
   }
#ifdef NEED_DEBUG
   if (con->pattern_tree) {
      ast_log(LOG_NOTICE,"match char tree after exten removal:\n");
      log_match_char_tree(con->pattern_tree, " ");
   }
#endif

   /* scan the extension list to find first matching extension-registrar */
   for (exten = con->root; exten; prev_exten = exten, exten = exten->next) {
      if (!strcmp(exten->exten, extension) &&
         (!registrar || !strcmp(exten->registrar, registrar)) &&
         (!matchcallerid || (!ast_strlen_zero(callerid) && !ast_strlen_zero(exten->cidmatch) && !strcmp(exten->cidmatch, callerid)) || (ast_strlen_zero(callerid) && ast_strlen_zero(exten->cidmatch))))
         break;
   }
   if (!exten) {
      /* we can't find right extension */
      if (!already_locked)
         ast_unlock_context(con);
      return -1;
   }

   /* scan the priority list to remove extension with exten->priority == priority */
   for (peer = exten, next_peer = exten->peer ? exten->peer : exten->next;
       peer && !strcmp(peer->exten, extension) && (!matchcallerid || (!ast_strlen_zero(callerid) && !ast_strlen_zero(peer->cidmatch) && !strcmp(peer->cidmatch,callerid)) || (ast_strlen_zero(callerid) && ast_strlen_zero(peer->cidmatch)));
         peer = next_peer, next_peer = next_peer ? (next_peer->peer ? next_peer->peer : next_peer->next) : NULL) {
      if ((priority == 0 || peer->priority == priority) &&
            (!callerid || !matchcallerid || (matchcallerid && !strcmp(peer->cidmatch, callerid))) &&
            (!registrar || !strcmp(peer->registrar, registrar) )) {
         found = 1;

         /* we are first priority extension? */
         if (!previous_peer) {
            /*
             * We are first in the priority chain, so must update the extension chain.
             * The next node is either the next priority or the next extension
             */
            struct ast_exten *next_node = peer->peer ? peer->peer : peer->next;
            if (peer->peer) {
               /* move the peer_table and peer_label_table down to the next peer, if
                  it is there */
               peer->peer->peer_table = peer->peer_table;
               peer->peer->peer_label_table = peer->peer_label_table;
               peer->peer_table = NULL;
               peer->peer_label_table = NULL;
            }
            if (!prev_exten) {   /* change the root... */
               con->root = next_node;
            } else {
               prev_exten->next = next_node; /* unlink */
            }
            if (peer->peer)   { /* update the new head of the pri list */
               peer->peer->next = peer->next;
            }
         } else { /* easy, we are not first priority in extension */
            previous_peer->peer = peer->peer;
         }

         /* now, free whole priority extension */
         destroy_exten(peer);
      } else {
         previous_peer = peer;
      }
   }
   if (!already_locked)
      ast_unlock_context(con);
   return found ? 0 : -1;
}


/*!
 * \note This function locks contexts list by &conlist, searches for the right context
 * structure, and locks the macrolock mutex in that context.
 * macrolock is used to limit a macro to be executed by one call at a time.
 * \param context The context
 */
int ast_context_lockmacro(const char *context)
{
   struct ast_context *c;
   int ret = -1;

   c = find_context_locked(context);
   if (c) {
      ast_unlock_contexts();

      /* if we found context, lock macrolock */
      ret = ast_mutex_lock(&c->macrolock);
   }

   return ret;
}

/*!
 * \note This function locks contexts list by &conlist, searches for the right context
 * structure, and unlocks the macrolock mutex in that context.
 * macrolock is used to limit a macro to be executed by one call at a time.
 * \param context The context
 */
int ast_context_unlockmacro(const char *context)
{
   struct ast_context *c;
   int ret = -1;

   c = find_context_locked(context);
   if (c) {
      ast_unlock_contexts();

      /* if we found context, unlock macrolock */
      ret = ast_mutex_unlock(&c->macrolock);
   }

   return ret;
}

/*! \brief Dynamically register a new dial plan application */
int ast_register_application2(const char *app, int (*execute)(struct ast_channel *, const char *), const char *synopsis, const char *description, void *mod)
{
   struct ast_app *tmp, *cur = NULL;
   char tmps[80];
   int length, res;
#ifdef AST_XML_DOCS
   char *tmpxml;
#endif

   AST_RWLIST_WRLOCK(&apps);
   AST_RWLIST_TRAVERSE(&apps, tmp, list) {
      if (!(res = strcasecmp(app, tmp->name))) {
         ast_log(LOG_WARNING, "Already have an application '%s'\n", app);
         AST_RWLIST_UNLOCK(&apps);
         return -1;
      } else if (res < 0)
         break;
   }

   length = sizeof(*tmp) + strlen(app) + 1;

   if (!(tmp = ast_calloc(1, length))) {
      AST_RWLIST_UNLOCK(&apps);
      return -1;
   }

   if (ast_string_field_init(tmp, 128)) {
      AST_RWLIST_UNLOCK(&apps);
      ast_free(tmp);
      return -1;
   }

   strcpy(tmp->name, app);
   tmp->execute = execute;
   tmp->module = mod;

#ifdef AST_XML_DOCS
   /* Try to lookup the docs in our XML documentation database */
   if (ast_strlen_zero(synopsis) && ast_strlen_zero(description)) {
      /* load synopsis */
      tmpxml = ast_xmldoc_build_synopsis("application", app, ast_module_name(tmp->module));
      ast_string_field_set(tmp, synopsis, tmpxml);
      ast_free(tmpxml);

      /* load description */
      tmpxml = ast_xmldoc_build_description("application", app, ast_module_name(tmp->module));
      ast_string_field_set(tmp, description, tmpxml);
      ast_free(tmpxml);

      /* load syntax */
      tmpxml = ast_xmldoc_build_syntax("application", app, ast_module_name(tmp->module));
      ast_string_field_set(tmp, syntax, tmpxml);
      ast_free(tmpxml);

      /* load arguments */
      tmpxml = ast_xmldoc_build_arguments("application", app, ast_module_name(tmp->module));
      ast_string_field_set(tmp, arguments, tmpxml);
      ast_free(tmpxml);

      /* load seealso */
      tmpxml = ast_xmldoc_build_seealso("application", app, ast_module_name(tmp->module));
      ast_string_field_set(tmp, seealso, tmpxml);
      ast_free(tmpxml);
      tmp->docsrc = AST_XML_DOC;
   } else {
#endif
      ast_string_field_set(tmp, synopsis, synopsis);
      ast_string_field_set(tmp, description, description);
#ifdef AST_XML_DOCS
      tmp->docsrc = AST_STATIC_DOC;
   }
#endif

   /* Store in alphabetical order */
   AST_RWLIST_TRAVERSE_SAFE_BEGIN(&apps, cur, list) {
      if (strcasecmp(tmp->name, cur->name) < 0) {
         AST_RWLIST_INSERT_BEFORE_CURRENT(tmp, list);
         break;
      }
   }
   AST_RWLIST_TRAVERSE_SAFE_END;
   if (!cur)
      AST_RWLIST_INSERT_TAIL(&apps, tmp, list);

   ast_verb(2, "Registered application '%s'\n", term_color(tmps, tmp->name, COLOR_BRCYAN, 0, sizeof(tmps)));

   AST_RWLIST_UNLOCK(&apps);

   return 0;
}

/*
 * Append to the list. We don't have a tail pointer because we need
 * to scan the list anyways to check for duplicates during insertion.
 */
int ast_register_switch(struct ast_switch *sw)
{
   struct ast_switch *tmp;

   AST_RWLIST_WRLOCK(&switches);
   AST_RWLIST_TRAVERSE(&switches, tmp, list) {
      if (!strcasecmp(tmp->name, sw->name)) {
         AST_RWLIST_UNLOCK(&switches);
         ast_log(LOG_WARNING, "Switch '%s' already found\n", sw->name);
         return -1;
      }
   }
   AST_RWLIST_INSERT_TAIL(&switches, sw, list);
   AST_RWLIST_UNLOCK(&switches);

   return 0;
}

void ast_unregister_switch(struct ast_switch *sw)
{
   AST_RWLIST_WRLOCK(&switches);
   AST_RWLIST_REMOVE(&switches, sw, list);
   AST_RWLIST_UNLOCK(&switches);
}

/*
 * Help for CLI commands ...
 */

static void print_app_docs(struct ast_app *aa, int fd)
{
   /* Maximum number of characters added by terminal coloring is 22 */
   char infotitle[64 + AST_MAX_APP + 22], syntitle[40], destitle[40], stxtitle[40], argtitle[40];
   char seealsotitle[40];
   char info[64 + AST_MAX_APP], *synopsis = NULL, *description = NULL, *syntax = NULL, *arguments = NULL;
   char *seealso = NULL;
   int syntax_size, synopsis_size, description_size, arguments_size, seealso_size;

   snprintf(info, sizeof(info), "\n  -= Info about application '%s' =- \n\n", aa->name);
   term_color(infotitle, info, COLOR_MAGENTA, 0, sizeof(infotitle));

   term_color(syntitle, "[Synopsis]\n", COLOR_MAGENTA, 0, 40);
   term_color(destitle, "[Description]\n", COLOR_MAGENTA, 0, 40);
   term_color(stxtitle, "[Syntax]\n", COLOR_MAGENTA, 0, 40);
   term_color(argtitle, "[Arguments]\n", COLOR_MAGENTA, 0, 40);
   term_color(seealsotitle, "[See Also]\n", COLOR_MAGENTA, 0, 40);

#ifdef AST_XML_DOCS
   if (aa->docsrc == AST_XML_DOC) {
      description = ast_xmldoc_printable(S_OR(aa->description, "Not available"), 1);
      arguments = ast_xmldoc_printable(S_OR(aa->arguments, "Not available"), 1);
      synopsis = ast_xmldoc_printable(S_OR(aa->synopsis, "Not available"), 1);
      seealso = ast_xmldoc_printable(S_OR(aa->seealso, "Not available"), 1);

      if (!synopsis || !description || !arguments || !seealso) {
         goto return_cleanup;
      }
   } else
#endif
   {
      synopsis_size = strlen(S_OR(aa->synopsis, "Not Available")) + AST_TERM_MAX_ESCAPE_CHARS;
      synopsis = ast_malloc(synopsis_size);

      description_size = strlen(S_OR(aa->description, "Not Available")) + AST_TERM_MAX_ESCAPE_CHARS;
      description = ast_malloc(description_size);

      arguments_size = strlen(S_OR(aa->arguments, "Not Available")) + AST_TERM_MAX_ESCAPE_CHARS;
      arguments = ast_malloc(arguments_size);

      seealso_size = strlen(S_OR(aa->seealso, "Not Available")) + AST_TERM_MAX_ESCAPE_CHARS;
      seealso = ast_malloc(seealso_size);

      if (!synopsis || !description || !arguments || !seealso) {
         goto return_cleanup;
      }

      term_color(synopsis, S_OR(aa->synopsis, "Not available"), COLOR_CYAN, 0, synopsis_size);
      term_color(description, S_OR(aa->description, "Not available"),   COLOR_CYAN, 0, description_size);
      term_color(arguments, S_OR(aa->arguments, "Not available"), COLOR_CYAN, 0, arguments_size);
      term_color(seealso, S_OR(aa->seealso, "Not available"), COLOR_CYAN, 0, seealso_size);
   }

   /* Handle the syntax the same for both XML and raw docs */
   syntax_size = strlen(S_OR(aa->syntax, "Not Available")) + AST_TERM_MAX_ESCAPE_CHARS;
   if (!(syntax = ast_malloc(syntax_size))) {
      goto return_cleanup;
   }
   term_color(syntax, S_OR(aa->syntax, "Not available"), COLOR_CYAN, 0, syntax_size);

   ast_cli(fd, "%s%s%s\n\n%s%s\n\n%s%s\n\n%s%s\n\n%s%s\n",
         infotitle, syntitle, synopsis, destitle, description,
         stxtitle, syntax, argtitle, arguments, seealsotitle, seealso);

return_cleanup:
   ast_free(description);
   ast_free(arguments);
   ast_free(synopsis);
   ast_free(seealso);
   ast_free(syntax);
}

/*
 * \brief 'show application' CLI command implementation function...
 */
static char *handle_show_application(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct ast_app *aa;
   int app, no_registered_app = 1;

   switch (cmd) {
   case CLI_INIT:
      e->command = "core show application";
      e->usage =
         "Usage: core show application <application> [<application> [<application> [...]]]\n"
         "       Describes a particular application.\n";
      return NULL;
   case CLI_GENERATE:
      /*
       * There is a possibility to show informations about more than one
       * application at one time. You can type 'show application Dial Echo' and
       * you will see informations about these two applications ...
       */
      return ast_complete_applications(a->line, a->word, a->n);
   }

   if (a->argc < 4) {
      return CLI_SHOWUSAGE;
   }

   AST_RWLIST_RDLOCK(&apps);
   AST_RWLIST_TRAVERSE(&apps, aa, list) {
      /* Check for each app that was supplied as an argument */
      for (app = 3; app < a->argc; app++) {
         if (strcasecmp(aa->name, a->argv[app])) {
            continue;
         }

         /* We found it! */
         no_registered_app = 0;

         print_app_docs(aa, a->fd);
      }
   }
   AST_RWLIST_UNLOCK(&apps);

   /* we found at least one app? no? */
   if (no_registered_app) {
      ast_cli(a->fd, "Your application(s) is (are) not registered\n");
      return CLI_FAILURE;
   }

   return CLI_SUCCESS;
}

/*! \brief  handle_show_hints: CLI support for listing registered dial plan hints */
static char *handle_show_hints(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct ast_hint *hint;
   int num = 0;
   int watchers;
   struct ao2_iterator i;

   switch (cmd) {
   case CLI_INIT:
      e->command = "core show hints";
      e->usage =
         "Usage: core show hints\n"
         "       List registered hints\n";
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   if (ao2_container_count(hints) == 0) {
      ast_cli(a->fd, "There are no registered dialplan hints\n");
      return CLI_SUCCESS;
   }
   /* ... we have hints ... */
   ast_cli(a->fd, "\n    -= Registered Asterisk Dial Plan Hints =-\n");

   i = ao2_iterator_init(hints, 0);
   for (; (hint = ao2_iterator_next(&i)); ao2_ref(hint, -1)) {
      ao2_lock(hint);
      if (!hint->exten) {
         /* The extension has already been destroyed */
         ao2_unlock(hint);
         continue;
      }
      watchers = ao2_container_count(hint->callbacks);
      ast_cli(a->fd, "   %20s@%-20.20s: %-20.20s  State:%-15.15s Watchers %2d\n",
         ast_get_extension_name(hint->exten),
         ast_get_context_name(ast_get_extension_context(hint->exten)),
         ast_get_extension_app(hint->exten),
         ast_extension_state2str(hint->laststate), watchers);
      ao2_unlock(hint);
      num++;
   }
   ao2_iterator_destroy(&i);

   ast_cli(a->fd, "----------------\n");
   ast_cli(a->fd, "- %d hints registered\n", num);
   return CLI_SUCCESS;
}

/*! \brief autocomplete for CLI command 'core show hint' */
static char *complete_core_show_hint(const char *line, const char *word, int pos, int state)
{
   struct ast_hint *hint;
   char *ret = NULL;
   int which = 0;
   int wordlen;
   struct ao2_iterator i;

   if (pos != 3)
      return NULL;

   wordlen = strlen(word);

   /* walk through all hints */
   i = ao2_iterator_init(hints, 0);
   for (; (hint = ao2_iterator_next(&i)); ao2_ref(hint, -1)) {
      ao2_lock(hint);
      if (!hint->exten) {
         /* The extension has already been destroyed */
         ao2_unlock(hint);
         continue;
      }
      if (!strncasecmp(word, ast_get_extension_name(hint->exten), wordlen) && ++which > state) {
         ret = ast_strdup(ast_get_extension_name(hint->exten));
         ao2_unlock(hint);
         ao2_ref(hint, -1);
         break;
      }
      ao2_unlock(hint);
   }
   ao2_iterator_destroy(&i);

   return ret;
}

/*! \brief  handle_show_hint: CLI support for listing registered dial plan hint */
static char *handle_show_hint(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   struct ast_hint *hint;
   int watchers;
   int num = 0, extenlen;
   struct ao2_iterator i;

   switch (cmd) {
   case CLI_INIT:
      e->command = "core show hint";
      e->usage =
         "Usage: core show hint <exten>\n"
         "       List registered hint\n";
      return NULL;
   case CLI_GENERATE:
      return complete_core_show_hint(a->line, a->word, a->pos, a->n);
   }

   if (a->argc < 4)
      return CLI_SHOWUSAGE;

   if (ao2_container_count(hints) == 0) {
      ast_cli(a->fd, "There are no registered dialplan hints\n");
      return CLI_SUCCESS;
   }

   extenlen = strlen(a->argv[3]);
   i = ao2_iterator_init(hints, 0);
   for (; (hint = ao2_iterator_next(&i)); ao2_ref(hint, -1)) {
      ao2_lock(hint);
      if (!hint->exten) {
         /* The extension has already been destroyed */
         ao2_unlock(hint);
         continue;
      }
      if (!strncasecmp(ast_get_extension_name(hint->exten), a->argv[3], extenlen)) {
         watchers = ao2_container_count(hint->callbacks);
         ast_cli(a->fd, "   %20s@%-20.20s: %-20.20s  State:%-15.15s Watchers %2d\n",
            ast_get_extension_name(hint->exten),
            ast_get_context_name(ast_get_extension_context(hint->exten)),
            ast_get_extension_app(hint->exten),
            ast_extension_state2str(hint->laststate), watchers);
         num++;
      }
      ao2_unlock(hint);
   }
   ao2_iterator_destroy(&i);
   if (!num)
      ast_cli(a->fd, "No hints matching extension %s\n", a->argv[3]);
   else
      ast_cli(a->fd, "%d hint%s matching extension %s\n", num, (num!=1 ? "s":""), a->