app_directed_pickup.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2005, Joshua Colp
 *
 * Joshua Colp <jcolp@digium.com>
 *
 * Portions merged from app_pickupchan, which was
 * Copyright (C) 2008, Gary Cook
 *
 * 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 Directed Call Pickup Support
 *
 * \author Joshua Colp <jcolp@digium.com>
 * \author Gary Cook
 *
 * \ingroup applications
 */

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 318735 $")

#include "asterisk/file.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/module.h"
#include "asterisk/lock.h"
#include "asterisk/app.h"
#include "asterisk/features.h"

#define PICKUPMARK "PICKUPMARK"

/*** DOCUMENTATION
   <application name="Pickup" language="en_US">
      <synopsis>
         Directed extension call pickup.
      </synopsis>
      <syntax argsep="&amp;">
         <parameter name="ext" argsep="@" required="true">
            <argument name="extension" required="true"/>
            <argument name="context" />
         </parameter>
         <parameter name="ext2" argsep="@" multiple="true">
            <argument name="extension2" required="true"/>
            <argument name="context2"/>
         </parameter>
      </syntax>
      <description>
         <para>This application can pickup any ringing channel that is calling
         the specified <replaceable>extension</replaceable>. If no <replaceable>context</replaceable>
         is specified, the current context will be used. If you use the special string <literal>PICKUPMARK</literal>
         for the context parameter, for example 10@PICKUPMARK, this application
         tries to find a channel which has defined a <variable>PICKUPMARK</variable>
         channel variable with the same value as <replaceable>extension</replaceable>
         (in this example, <literal>10</literal>). When no parameter is specified, the application
         will pickup a channel matching the pickup group of the active channel.</para>
      </description>
   </application>
   <application name="PickupChan" language="en_US">
      <synopsis>
         Pickup a ringing channel.
      </synopsis>
      <syntax argsep="&amp;">
         <parameter name="channel" required="true" />
         <parameter name="channel2" multiple="true" />
      </syntax>
      <description>
         <para>This will pickup a specified <replaceable>channel</replaceable> if ringing.</para>
      </description>
   </application>
 ***/

static const char *app = "Pickup";
static const char *app2 = "PickupChan";
/*! \todo This application should return a result code, like PICKUPRESULT */

/* Helper function that determines whether a channel is capable of being picked up */
static int can_pickup(struct ast_channel *chan)
{
   if (!chan->pbx && !chan->masq &&
      !ast_test_flag(chan, AST_FLAG_ZOMBIE) &&
      (chan->_state == AST_STATE_RINGING ||
       chan->_state == AST_STATE_RING ||
       chan->_state == AST_STATE_DOWN)) {
      return 1;
   }
   return 0;
}

/*! \brief Helper Function to walk through ALL channels checking NAME and STATE */
static struct ast_channel *my_ast_get_channel_by_name_locked(const char *channame)
{
   struct ast_channel *chan;
   char *chkchan;
   size_t channame_len, chkchan_len;

   channame_len = strlen(channame);

   /* Check if channel name contains a '-'.
    * In this case the channel name will be interpreted as full channel name.
    */
   if (strchr(channame, '-')) {
      /* check full channel name */
      chkchan_len = channame_len;
      chkchan = (char *)channame;
   } else {
      /* need to append a '-' for the comparison so we check full channel name,
       * i.e SIP/hgc- , use a temporary variable so original stays the same for
       * debugging.
       */
      chkchan_len = channame_len + 1;
      chkchan = alloca(chkchan_len + 1);
      strcpy(chkchan, channame);
      strcat(chkchan, "-");
   }

   for (chan = ast_walk_channel_by_name_prefix_locked(NULL, channame, channame_len);
       chan;
       chan = ast_walk_channel_by_name_prefix_locked(chan, channame, channame_len)) {
      if (!strncasecmp(chan->name, chkchan, chkchan_len) && can_pickup(chan)) {
         return chan;
      }
      ast_channel_unlock(chan);
   }
   return NULL;
}

/*! \brief Attempt to pick up specified channel named , does not use context */
static int pickup_by_channel(struct ast_channel *chan, char *pickup)
{
   int res = 0;
   struct ast_channel *target;

   if (!(target = my_ast_get_channel_by_name_locked(pickup)))
      return -1;

   /* Just check that we are not picking up the SAME as target */
   if (chan != target) {
      res = ast_do_pickup(chan, target);
   }
   ast_channel_unlock(target);

   return res;
}

struct pickup_criteria {
   const char *exten;
   const char *context;
   struct ast_channel *chan;
};

static int find_by_exten(struct ast_channel *c, void *data)
{
   struct pickup_criteria *info = data;

   return (!strcasecmp(c->macroexten, info->exten) || !strcasecmp(c->exten, info->exten)) &&
      !strcasecmp(c->dialcontext, info->context) &&
      (info->chan != c) && can_pickup(c);
}

/* Attempt to pick up specified extension with context */
static int pickup_by_exten(struct ast_channel *chan, const char *exten, const char *context)
{
   struct ast_channel *target = NULL;
   struct pickup_criteria search = {
      .exten = exten,
      .context = context,
      .chan = chan,
   };

   target = ast_channel_search_locked(find_by_exten, &search);

   if (target) {
      int res = ast_do_pickup(chan, target);
      ast_channel_unlock(target);
      return res;
   }

   return -1;
}

static int find_by_mark(struct ast_channel *c, void *data)
{
   const char *mark = data;
   const char *tmp;

   return (tmp = pbx_builtin_getvar_helper(c, PICKUPMARK)) &&
      !strcasecmp(tmp, mark) &&
      can_pickup(c);
}

/* Attempt to pick up specified mark */
static int pickup_by_mark(struct ast_channel *chan, const char *mark)
{
   struct ast_channel *target = ast_channel_search_locked(find_by_mark, (char *) mark);

   if (target) {
      int res = ast_do_pickup(chan, target);
      ast_channel_unlock(target);
      return res;
   }

   return -1;
}

static int find_by_group(struct ast_channel *c, void *data)
{
   struct ast_channel *chan = data;

   return (c != chan) && (chan->pickupgroup & c->callgroup) && can_pickup(c);
}

static int pickup_by_group(struct ast_channel *chan)
{
   struct ast_channel *target = ast_channel_search_locked(find_by_group, chan);

   if (target) {
      int res;

      ast_log(LOG_NOTICE, "%s, pickup attempt by %s\n", target->name, chan->name);
      res = ast_do_pickup(chan, target);
      ast_channel_unlock(target);
      return res;
   }

   return -1;
}

/* application entry point for Pickup() */
static int pickup_exec(struct ast_channel *chan, void *data)
{
   int res = 0;
   char *tmp = ast_strdupa(data);
   char *exten = NULL, *context = NULL;

   if (ast_strlen_zero(data)) {
      res = pickup_by_group(chan);
      return res;
   }

   /* Parse extension (and context if there) */
   while (!ast_strlen_zero(tmp) && (exten = strsep(&tmp, "&"))) {
      if ((context = strchr(exten, '@')))
         *context++ = '\0';
      if (!ast_strlen_zero(context) && !strcasecmp(context, PICKUPMARK)) {
         if (!pickup_by_mark(chan, exten))
            break;
      } else {
         if (!pickup_by_exten(chan, exten, !ast_strlen_zero(context) ? context : chan->context))
            break;
      }
      ast_log(LOG_NOTICE, "No target channel found for %s.\n", exten);
   }

   return res;
}

/* application entry point for PickupChan() */
static int pickupchan_exec(struct ast_channel *chan, void *data)
{
   int res = 0;
   char *tmp = ast_strdupa(data);
   char *pickup = NULL;

   if (ast_strlen_zero(data)) {
      ast_log(LOG_WARNING, "PickupChan requires an argument (channel)!\n");
      return -1;  
   }

   /* Parse channel */
   while (!ast_strlen_zero(tmp) && (pickup = strsep(&tmp, "&"))) {
      if (!strncasecmp(chan->name, pickup, strlen(pickup))) {
         ast_log(LOG_NOTICE, "Cannot pickup your own channel %s.\n", pickup);
      } else {
         if (!pickup_by_channel(chan, pickup)) {
            break;
         }
         ast_log(LOG_NOTICE, "No target channel found for %s.\n", pickup);
      }
   }

   return res;
}

static int unload_module(void)
{
   int res;

   res = ast_unregister_application(app);
   res |= ast_unregister_application(app2);

   return res;
}

static int load_module(void)
{
   int res;

   res = ast_register_application_xml(app, pickup_exec);
   res |= ast_register_application_xml(app2, pickupchan_exec);

   return res;
}

AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Directed Call Pickup Application");