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
 */

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

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 373220 $")

#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"
#include "asterisk/manager.h"
#include "asterisk/callerid.h"
#include "asterisk/cel.h"

#define PICKUPMARK "PICKUPMARK"

/*** DOCUMENTATION
   <application name="Pickup" language="en_US">
      <synopsis>
         Directed extension call pickup.
      </synopsis>
      <syntax>
         <parameter name="targets" argsep="&amp;">
            <argument name="extension" argsep="@" required="true">
               <para>Specification of the pickup target.</para>
               <argument name="extension" required="true"/>
               <argument name="context" />
            </argument>
            <argument name="extension2" argsep="@" multiple="true">
               <para>Additional specifications of pickup targets.</para>
               <argument name="extension2" required="true"/>
               <argument name="context2"/>
            </argument>
         </parameter>
      </syntax>
      <description>
         <para>This application can pickup a specified ringing channel.  The channel
         to pickup can be specified in the following ways.</para>
         <para>1) If no <replaceable>extension</replaceable> targets are specified,
         the application will pickup a channel matching the pickup group of the
         requesting channel.</para>
         <para>2) If the <replaceable>extension</replaceable> is specified with a
         <replaceable>context</replaceable> of the special string
         <literal>PICKUPMARK</literal> (for example 10@PICKUPMARK), the application
         will pickup a channel which has defined the channel variable
         <variable>PICKUPMARK</variable> with the same value as
         <replaceable>extension</replaceable> (in this example,
         <literal>10</literal>).</para>
         <para>3) If the <replaceable>extension</replaceable> is specified
         with or without a <replaceable>context</replaceable>, the channel with a
         matching <replaceable>extension</replaceable> and <replaceable>context</replaceable>
         will be picked up.  If no <replaceable>context</replaceable> is specified,
         the current context will be used.</para>
         <note><para>The <replaceable>extension</replaceable> is typically set on
         matching channels by the dial application that created the channel.  The
         <replaceable>context</replaceable> is set on matching channels by the
         channel driver for the device.</para></note>
      </description>
   </application>
   <application name="PickupChan" language="en_US">
      <synopsis>
         Pickup a ringing channel.
      </synopsis>
      <syntax >
         <parameter name="Technology/Resource" argsep="&amp;" required="true">
            <argument name="Technology/Resource" required="true" />
            <argument name="Technology2/Resource2" required="false" multiple="true" />
         </parameter>
         <parameter name="options" required="false">
            <optionlist>
               <option name="p">
                  <para>Channel name specified partial name. Used when find channel by callid.</para>
               </option>
            </optionlist>
         </parameter>
      </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";

struct pickup_by_name_args {
   const char *name;
   size_t len;
};

static int pickup_by_name_cb(void *obj, void *arg, void *data, int flags)
{
   struct ast_channel *target = obj;/*!< Potential pickup target */
   struct pickup_by_name_args *args = data;

   ast_channel_lock(target);
   if (!strncasecmp(ast_channel_name(target), args->name, args->len) && ast_can_pickup(target)) {
      /* Return with the channel still locked on purpose */
      return CMP_MATCH | CMP_STOP;
   }
   ast_channel_unlock(target);

   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)
{
   char *chkchan;
   struct pickup_by_name_args pickup_args;

   /* 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 */
      pickup_args.len = strlen(channame);
      pickup_args.name = 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.
       */
      pickup_args.len = strlen(channame) + 1;
      chkchan = ast_alloca(pickup_args.len + 1);
      strcpy(chkchan, channame);
      strcat(chkchan, "-");
      pickup_args.name = chkchan;
   }

   return ast_channel_callback(pickup_by_name_cb, NULL, &pickup_args, 0);
}

/*! \brief Attempt to pick up named channel, does not use context */
static int pickup_by_channel(struct ast_channel *chan, char *pickup)
{
   int res = -1;
   struct ast_channel *target;/*!< Potential pickup target */

   target = my_ast_get_channel_by_name_locked(pickup);
   if (target) {
      /* Just check that we are not picking up the SAME as target. (i.e. ourself) */
      if (chan != target) {
         res = ast_do_pickup(chan, target);
      }
      ast_channel_unlock(target);
      target = ast_channel_unref(target);
   }

   return res;
}

/* 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;/*!< Potential pickup target */
   struct ast_channel_iterator *iter;
   int res = -1;

   if (!(iter = ast_channel_iterator_by_exten_new(exten, context))) {
      return -1;
   }

   while ((target = ast_channel_iterator_next(iter))) {
      ast_channel_lock(target);
      if ((chan != target) && ast_can_pickup(target)) {
         ast_log(LOG_NOTICE, "%s pickup by %s\n", ast_channel_name(target), ast_channel_name(chan));
         break;
      }
      ast_channel_unlock(target);
      target = ast_channel_unref(target);
   }

   ast_channel_iterator_destroy(iter);

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

   return res;
}

static int find_by_mark(void *obj, void *arg, void *data, int flags)
{
   struct ast_channel *target = obj;/*!< Potential pickup target */
   const char *mark = data;
   const char *tmp;

   ast_channel_lock(target);
   tmp = pbx_builtin_getvar_helper(target, PICKUPMARK);
   if (tmp && !strcasecmp(tmp, mark) && ast_can_pickup(target)) {
      /* Return with the channel still locked on purpose */
      return CMP_MATCH | CMP_STOP;
   }
   ast_channel_unlock(target);

   return 0;
}

/* Attempt to pick up specified mark */
static int pickup_by_mark(struct ast_channel *chan, const char *mark)
{
   struct ast_channel *target;/*!< Potential pickup target */
   int res = -1;

   /* The found channel is already locked. */
   target = ast_channel_callback(find_by_mark, NULL, (char *) mark, 0);
   if (target) {
      res = ast_do_pickup(chan, target);
      ast_channel_unlock(target);
      target = ast_channel_unref(target);
   }

   return res;
}

static int pickup_by_group(struct ast_channel *chan)
{
   struct ast_channel *target;/*!< Potential pickup target */
   int res = -1;

   /* The found channel is already locked. */
   target = ast_pickup_find_by_group(chan);
   if (target) {
      ast_log(LOG_NOTICE, "pickup %s attempt by %s\n", ast_channel_name(target), ast_channel_name(chan));
      res = ast_do_pickup(chan, target);
      ast_channel_unlock(target);
      target = ast_channel_unref(target);
   }

   return res;
}

/* application entry point for Pickup() */
static int pickup_exec(struct ast_channel *chan, const char *data)
{
   char *tmp;
   char *exten;
   char *context;

   if (ast_strlen_zero(data)) {
      return pickup_by_group(chan) ? 0 : -1;
   }

   /* Parse extension (and context if there) */
   tmp = ast_strdupa(data);
   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)) {
            /* Pickup successful.  Stop the dialplan this channel is a zombie. */
            return -1;
         }
      } else {
         if (ast_strlen_zero(context)) {
            context = (char *) ast_channel_context(chan);
         }
         if (!pickup_by_exten(chan, exten, context)) {
            /* Pickup successful.  Stop the dialplan this channel is a zombie. */
            return -1;
         }
      }
      ast_log(LOG_NOTICE, "No target channel found for %s@%s.\n", exten, context);
   }

   /* Pickup failed.  Keep going in the dialplan. */
   return 0;
}

/* Find channel for pick up specified by partial channel name */ 
static int find_by_part(void *obj, void *arg, void *data, int flags)
{
   struct ast_channel *target = obj;/*!< Potential pickup target */
   const char *part = data;
   int len = strlen(part);

   ast_channel_lock(target);
   if (len <= strlen(ast_channel_name(target)) && !strncmp(ast_channel_name(target), part, len)
      && ast_can_pickup(target)) {
      /* Return with the channel still locked on purpose */
      return CMP_MATCH | CMP_STOP;
   }
   ast_channel_unlock(target);

   return 0;
}

/* Attempt to pick up specified by partial channel name */ 
static int pickup_by_part(struct ast_channel *chan, const char *part)
{
   struct ast_channel *target;/*!< Potential pickup target */
   int res = -1;

   /* The found channel is already locked. */
   target = ast_channel_callback(find_by_part, NULL, (char *) part, 0);
   if (target) {
      res = ast_do_pickup(chan, target);
      ast_channel_unlock(target);
      target = ast_channel_unref(target);
   }

   return res;
}

/* application entry point for PickupChan() */
static int pickupchan_exec(struct ast_channel *chan, const char *data)
{
   int partial_pickup = 0;
   char *pickup = NULL;
   char *parse = ast_strdupa(data);
   AST_DECLARE_APP_ARGS(args,
      AST_APP_ARG(channel);
      AST_APP_ARG(options);
   );
   AST_STANDARD_APP_ARGS(args, parse);

   if (ast_strlen_zero(args.channel)) {
      ast_log(LOG_WARNING, "PickupChan requires an argument (channel)!\n");
      /* Pickup failed.  Keep going in the dialplan. */
      return 0;
   }

   if (!ast_strlen_zero(args.options) && strchr(args.options, 'p')) {
      partial_pickup = 1;
   }

   /* Parse channel */
   while (!ast_strlen_zero(args.channel) && (pickup = strsep(&args.channel, "&"))) {
      if (!strncasecmp(ast_channel_name(chan), pickup, strlen(pickup))) {
         ast_log(LOG_NOTICE, "Cannot pickup your own channel %s.\n", pickup);
      } else {
         if (partial_pickup) {
            if (!pickup_by_part(chan, pickup)) {
               /* Pickup successful.  Stop the dialplan this channel is a zombie. */
               return -1;
            }
         } else if (!pickup_by_channel(chan, pickup)) {
            /* Pickup successful.  Stop the dialplan this channel is a zombie. */
            return -1;
         }
         ast_log(LOG_NOTICE, "No target channel found for %s.\n", pickup);
      }
   }

   /* Pickup failed.  Keep going in the dialplan. */
   return 0;
}

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");