pbx_hangup_handler.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2016, CFWare, LLC
 *
 * Corey Farrell <[email protected]>
 *
 * 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 PBX Hangup Handler management routines.
 *
 * \author Corey Farrell <[email protected]>
 */

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

#include "asterisk.h"

#include "asterisk/_private.h"
#include "asterisk/app.h"
#include "asterisk/cli.h"
#include "asterisk/linkedlists.h"
#include "asterisk/pbx.h"
#include "asterisk/stasis_channels.h"
#include "asterisk/utils.h"

/*!
 * \internal
 * \brief Publish a hangup handler related message to \ref stasis
 */
static void publish_hangup_handler_message(const char *action, struct ast_channel *chan, const char *handler)
{
   RAII_VAR(struct ast_json *, blob, NULL, ast_json_unref);

   blob = ast_json_pack("{s: s, s: s}",
         "type", action,
         "handler", S_OR(handler, ""));
   if (!blob) {
      return;
   }

   ast_channel_publish_blob(chan, ast_channel_hangup_handler_type(), blob);
}

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;
   }

   /*
    * 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_HANGUP_EXEC);

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

      publish_hangup_handler_message("run", 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) {
      publish_hangup_handler_message("pop", 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);
   publish_hangup_handler_message("push", 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 NULL;
   }

   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;
}

static struct ast_cli_entry cli[] = {
   AST_CLI_DEFINE(handle_show_hangup_all, "Show hangup handlers of all channels"),
   AST_CLI_DEFINE(handle_show_hangup_channel, "Show hangup handlers of a specified channel"),
};

static void unload_pbx_hangup_handler(void)
{
   ast_cli_unregister_multiple(cli, ARRAY_LEN(cli));
}

int load_pbx_hangup_handler(void)
{
   ast_cli_register_multiple(cli, ARRAY_LEN(cli));
   ast_register_cleanup(unload_pbx_hangup_handler);

   return 0;
}