res_stasis.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2012 - 2013, Digium, Inc.
 *
 * David M. Lee, II <dlee@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 Stasis application support.
 *
 * \author David M. Lee, II <dlee@digium.com>
 *
 * <code>res_stasis.so</code> brings together the various components of the
 * Stasis application infrastructure.
 *
 * First, there's the Stasis application handler, stasis_app_exec(). This is
 * called by <code>app_stasis.so</code> to give control of a channel to the
 * Stasis application code from the dialplan.
 *
 * While a channel is in stasis_app_exec(), it has a \ref stasis_app_control
 * object, which may be used to control the channel.
 *
 * To control the channel, commands may be sent to channel using
 * stasis_app_send_command() and stasis_app_send_async_command().
 *
 * Alongside this, applications may be registered/unregistered using
 * stasis_app_register()/stasis_app_unregister(). While a channel is in Stasis,
 * events received on the channel's topic are converted to JSON and forwarded to
 * the \ref stasis_app_cb. The application may also subscribe to the channel to
 * continue to receive messages even after the channel has left Stasis, but it
 * will not be able to control it.
 *
 * Given all the stuff that comes together in this module, it's been broken up
 * into several pieces that are in <code>res/stasis/</code> and compiled into
 * <code>res_stasis.so</code>.
 */
 
/*** MODULEINFO
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include "asterisk/astobj2.h"
#include "asterisk/callerid.h"
#include "asterisk/module.h"
#include "asterisk/stasis_app_impl.h"
#include "asterisk/stasis_channels.h"
#include "asterisk/stasis_bridges.h"
#include "asterisk/stasis_endpoints.h"
#include "asterisk/stasis_message_router.h"
#include "asterisk/strings.h"
#include "stasis/app.h"
#include "stasis/control.h"
#include "stasis/messaging.h"
#include "stasis/stasis_bridge.h"
#include "asterisk/core_unreal.h"
#include "asterisk/musiconhold.h"
#include "asterisk/causes.h"
#include "asterisk/stringfields.h"
#include "asterisk/bridge_after.h"
#include "asterisk/format_cache.h"
 
/*! Time to wait for a frame in the application */
#define MAX_WAIT_MS 200
 
/*!
 * \brief Number of buckets for the Stasis application hash table.  Remember to
 * keep it a prime number!
 */
#define APPS_NUM_BUCKETS 127
 
/*!
 * \brief Number of buckets for the Stasis application hash table.  Remember to
 * keep it a prime number!
 */
#define CONTROLS_NUM_BUCKETS 127
 
/*!
 * \brief Number of buckets for the Stasis bridges hash table.  Remember to
 * keep it a prime number!
 */
#define BRIDGES_NUM_BUCKETS 127
 
/*!
 * \brief Stasis application container.
 */
struct ao2_container *apps_registry;
 
struct ao2_container *app_controls;
 
struct ao2_container *app_bridges;
 
struct ao2_container *app_bridges_moh;
 
struct ao2_container *app_bridges_playback;
 
/*!
 * \internal \brief List of registered event sources.
 */
AST_RWLIST_HEAD_STATIC(event_sources, stasis_app_event_source);
 
static struct ast_json *stasis_end_to_json(struct stasis_message *message,
        const struct stasis_message_sanitizer *sanitize)
{
    struct ast_channel_blob *payload = stasis_message_data(message);
    struct ast_json *msg;
 
    if (sanitize && sanitize->channel_snapshot &&
            sanitize->channel_snapshot(payload->snapshot)) {
        return NULL;
    }
 
    msg = ast_json_pack("{s: s, s: O, s: o}",
        "type", "StasisEnd",
        "timestamp", ast_json_object_get(payload->blob, "timestamp"),
        "channel", ast_channel_snapshot_to_json(payload->snapshot, sanitize));
    if (!msg) {
        ast_log(LOG_ERROR, "Failed to pack JSON for StasisEnd message\n");
        return NULL;
    }
 
    return msg;
}
 
STASIS_MESSAGE_TYPE_DEFN_LOCAL(end_message_type,
    .to_json = stasis_end_to_json);
 
struct start_message_blob {
    struct ast_channel_snapshot *channel;       /*!< Channel that is entering Stasis() */
    struct ast_channel_snapshot *replace_channel;   /*!< Channel that is being replaced (optional) */
    struct ast_json *blob;              /*!< JSON blob containing timestamp and args */
};
 
static struct ast_json *stasis_start_to_json(struct stasis_message *message,
        const struct stasis_message_sanitizer *sanitize)
{
    struct start_message_blob *payload = stasis_message_data(message);
    struct ast_json *msg;
 
    if (sanitize && sanitize->channel_snapshot &&
            sanitize->channel_snapshot(payload->channel)) {
        return NULL;
    }
 
    msg = ast_json_pack("{s: s, s: O, s: O, s: o}",
        "type", "StasisStart",
        "timestamp", ast_json_object_get(payload->blob, "timestamp"),
        "args", ast_json_object_get(payload->blob, "args"),
        "channel", ast_channel_snapshot_to_json(payload->channel, NULL));
    if (!msg) {
        ast_log(LOG_ERROR, "Failed to pack JSON for StasisStart message\n");
        return NULL;
    }
 
    if (payload->replace_channel) {
        int res = ast_json_object_set(msg, "replace_channel",
            ast_channel_snapshot_to_json(payload->replace_channel, NULL));
 
        if (res) {
            ast_json_unref(msg);
            ast_log(LOG_ERROR, "Failed to append JSON for StasisStart message\n");
            return NULL;
        }
    }
 
    return msg;
}
 
STASIS_MESSAGE_TYPE_DEFN_LOCAL(start_message_type,
    .to_json = stasis_start_to_json);
 
/*! AO2 hash function for \ref app */
static int app_hash(const void *obj, const int flags)
{
    const struct stasis_app *app;
    const char *key;
 
    switch (flags & OBJ_SEARCH_MASK) {
    case OBJ_SEARCH_KEY:
        key = obj;
        break;
    case OBJ_SEARCH_OBJECT:
        app = obj;
        key = stasis_app_name(app);
        break;
    default:
        /* Hash can only work on something with a full key. */
        ast_assert(0);
        return 0;
    }
    return ast_str_hash(key);
}
 
/*! AO2 comparison function for \ref app */
static int app_compare(void *obj, void *arg, int flags)
{
    const struct stasis_app *object_left = obj;
    const struct stasis_app *object_right = arg;
    const char *right_key = arg;
    int cmp;
 
    switch (flags & OBJ_SEARCH_MASK) {
    case OBJ_SEARCH_OBJECT:
        right_key = stasis_app_name(object_right);
        /* Fall through */
    case OBJ_SEARCH_KEY:
        cmp = strcmp(stasis_app_name(object_left), right_key);
        break;
    case OBJ_SEARCH_PARTIAL_KEY:
        /*
         * We could also use a partial key struct containing a length
         * so strlen() does not get called for every comparison instead.
         */
        cmp = strncmp(stasis_app_name(object_left), right_key, strlen(right_key));
        break;
    default:
        /*
         * What arg points to is specific to this traversal callback
         * and has no special meaning to astobj2.
         */
        cmp = 0;
        break;
    }
    if (cmp) {
        return 0;
    }
    /*
     * At this point the traversal callback is identical to a sorted
     * container.
     */
    return CMP_MATCH;
}
 
/*! AO2 hash function for \ref stasis_app_control */
static int control_hash(const void *obj, const int flags)
{
    const struct stasis_app_control *control;
    const char *key;
 
    switch (flags & OBJ_SEARCH_MASK) {
    case OBJ_SEARCH_KEY:
        key = obj;
        break;
    case OBJ_SEARCH_OBJECT:
        control = obj;
        key = stasis_app_control_get_channel_id(control);
        break;
    default:
        /* Hash can only work on something with a full key. */
        ast_assert(0);
        return 0;
    }
    return ast_str_hash(key);
}
 
/*! AO2 comparison function for \ref stasis_app_control */
static int control_compare(void *obj, void *arg, int flags)
{
    const struct stasis_app_control *object_left = obj;
    const struct stasis_app_control *object_right = arg;
    const char *right_key = arg;
    int cmp;
 
    switch (flags & OBJ_SEARCH_MASK) {
    case OBJ_SEARCH_OBJECT:
        right_key = stasis_app_control_get_channel_id(object_right);
        /* Fall through */
    case OBJ_SEARCH_KEY:
        cmp = strcmp(stasis_app_control_get_channel_id(object_left), right_key);
        break;
    case OBJ_SEARCH_PARTIAL_KEY:
        /*
         * We could also use a partial key struct containing a length
         * so strlen() does not get called for every comparison instead.
         */
        cmp = strncmp(stasis_app_control_get_channel_id(object_left), right_key, strlen(right_key));
        break;
    default:
        /*
         * What arg points to is specific to this traversal callback
         * and has no special meaning to astobj2.
         */
        cmp = 0;
        break;
    }
    if (cmp) {
        return 0;
    }
    /*
     * At this point the traversal callback is identical to a sorted
     * container.
     */
    return CMP_MATCH;
}
 
static int cleanup_cb(void *obj, void *arg, int flags)
{
    struct stasis_app *app = obj;
 
    if (!app_is_finished(app)) {
        return 0;
    }
 
    ast_verb(1, "Shutting down application '%s'\n", stasis_app_name(app));
    app_shutdown(app);
 
    return CMP_MATCH;
 
}
 
/*!
 * \brief Clean up any old apps that we don't need any more.
 */
static void cleanup(void)
{
    ao2_callback(apps_registry, OBJ_MULTIPLE | OBJ_NODATA | OBJ_UNLINK,
        cleanup_cb, NULL);
}
 
struct stasis_app_control *stasis_app_control_create(struct ast_channel *chan)
{
    return control_create(chan, NULL);
}
 
struct stasis_app_control *stasis_app_control_find_by_channel(
    const struct ast_channel *chan)
{
    if (chan == NULL) {
        return NULL;
    }
 
    return stasis_app_control_find_by_channel_id(
        ast_channel_uniqueid(chan));
}
 
struct stasis_app_control *stasis_app_control_find_by_channel_id(
    const char *channel_id)
{
    return ao2_find(app_controls, channel_id, OBJ_SEARCH_KEY);
}
 
/*! AO2 hash function for bridges container  */
static int bridges_hash(const void *obj, const int flags)
{
    const struct ast_bridge *bridge;
    const char *key;
 
    switch (flags & OBJ_SEARCH_MASK) {
    case OBJ_SEARCH_KEY:
        key = obj;
        break;
    case OBJ_SEARCH_OBJECT:
        bridge = obj;
        key = bridge->uniqueid;
        break;
    default:
        /* Hash can only work on something with a full key. */
        ast_assert(0);
        return 0;
    }
    return ast_str_hash(key);
}
 
/*! AO2 comparison function for bridges container */
static int bridges_compare(void *obj, void *arg, int flags)
{
    const struct ast_bridge *object_left = obj;
    const struct ast_bridge *object_right = arg;
    const char *right_key = arg;
    int cmp;
 
    switch (flags & OBJ_SEARCH_MASK) {
    case OBJ_SEARCH_OBJECT:
        right_key = object_right->uniqueid;
        /* Fall through */
    case OBJ_SEARCH_KEY:
        cmp = strcmp(object_left->uniqueid, right_key);
        break;
    case OBJ_SEARCH_PARTIAL_KEY:
        /*
         * We could also use a partial key struct containing a length
         * so strlen() does not get called for every comparison instead.
         */
        cmp = strncmp(object_left->uniqueid, right_key, strlen(right_key));
        break;
    default:
        /*
         * What arg points to is specific to this traversal callback
         * and has no special meaning to astobj2.
         */
        cmp = 0;
        break;
    }
    if (cmp) {
        return 0;
    }
    /*
     * At this point the traversal callback is identical to a sorted
     * container.
     */
    return CMP_MATCH;
}
 
/*!
 *  Used with app_bridges_moh and app_bridge_control, they provide links
 *  between bridges and channels used for ARI application purposes
 */
struct stasis_app_bridge_channel_wrapper {
    AST_DECLARE_STRING_FIELDS(
        AST_STRING_FIELD(channel_id);
        AST_STRING_FIELD(bridge_id);
    );
};
 
/*! AO2 comparison function for bridges moh container */
static int bridges_channel_compare(void *obj, void *arg, int flags)
{
    const struct stasis_app_bridge_channel_wrapper *object_left = obj;
    const struct stasis_app_bridge_channel_wrapper *object_right = arg;
    const char *right_key = arg;
    int cmp;
 
    switch (flags & OBJ_SEARCH_MASK) {
    case OBJ_SEARCH_OBJECT:
            right_key = object_right->bridge_id;
    case OBJ_SEARCH_KEY:
            cmp = strcmp(object_left->bridge_id, right_key);
            break;
    case OBJ_SEARCH_PARTIAL_KEY:
            cmp = strncmp(object_left->bridge_id, right_key, strlen(right_key));
            break;
    default:
            cmp = 0;
            break;
    }
    if (cmp) {
        return 0;
    }
    return CMP_MATCH;
}
 
static void stasis_app_bridge_channel_wrapper_destructor(void *obj)
{
    struct stasis_app_bridge_channel_wrapper *wrapper = obj;
    ast_string_field_free_memory(wrapper);
}
 
/*! AO2 hash function for the bridges moh container */
static int bridges_channel_hash_fn(const void *obj, const int flags)
{
    const struct stasis_app_bridge_channel_wrapper *wrapper;
    const char *key;
 
    switch (flags & OBJ_SEARCH_MASK) {
    case OBJ_SEARCH_KEY:
        key = obj;
        break;
    case OBJ_SEARCH_OBJECT:
        wrapper = obj;
        key = wrapper->bridge_id;
        break;
    default:
        /* Hash can only work on something with a full key. */
        ast_assert(0);
        return 0;
    }
    return ast_str_hash(key);
}
 
static int bridges_channel_sort_fn(const void *obj_left, const void *obj_right, const int flags)
{
    const struct stasis_app_bridge_channel_wrapper *left = obj_left;
    const struct stasis_app_bridge_channel_wrapper *right = obj_right;
    const char *right_key = obj_right;
    int cmp;
 
    switch (flags & OBJ_SEARCH_MASK) {
    case OBJ_SEARCH_OBJECT:
        right_key = right->bridge_id;
        /* Fall through */
    case OBJ_SEARCH_KEY:
        cmp = strcmp(left->bridge_id, right_key);
        break;
    case OBJ_SEARCH_PARTIAL_KEY:
        cmp = strncmp(left->bridge_id, right_key, strlen(right_key));
        break;
    default:
        /* Sort can only work on something with a full or partial key. */
        ast_assert(0);
        cmp = 0;
        break;
    }
    return cmp;
}
 
/*! Request a bridge MOH channel */
static struct ast_channel *prepare_bridge_moh_channel(void)
{
    struct ast_channel *chan;
    struct ast_format_cap *cap;
 
    cap = ast_format_cap_alloc(AST_FORMAT_CAP_FLAG_DEFAULT);
    if (!cap) {
        return NULL;
    }
 
    ast_format_cap_append(cap, ast_format_slin, 0);
 
    chan = ast_request("Announcer", cap, NULL, NULL, "ARI_MOH", NULL);
    ao2_ref(cap, -1);
 
    return chan;
}
 
/*! Provides the moh channel with a thread so it can actually play its music */
static void *moh_channel_thread(void *data)
{
    struct stasis_app_bridge_channel_wrapper *moh_wrapper = data;
    struct ast_channel *moh_channel = ast_channel_get_by_name(moh_wrapper->channel_id);
    struct ast_frame *f;
 
    if (!moh_channel) {
        ao2_unlink(app_bridges_moh, moh_wrapper);
        ao2_ref(moh_wrapper, -1);
        return NULL;
    }
 
    /* Read and discard any frame coming from the stasis bridge. */
    for (;;) {
        if (ast_waitfor(moh_channel, -1) < 0) {
            /* Error or hungup */
            break;
        }
 
        f = ast_read(moh_channel);
        if (!f) {
            /* Hungup */
            break;
        }
        ast_frfree(f);
    }
 
    ao2_unlink(app_bridges_moh, moh_wrapper);
    ao2_ref(moh_wrapper, -1);
 
    ast_moh_stop(moh_channel);
    ast_hangup(moh_channel);
 
    return NULL;
}
 
/*!
 * \internal
 * \brief Creates, pushes, and links a channel for playing music on hold to bridge
 *
 * \param bridge Which bridge this moh channel exists for
 *
 * \retval NULL if the channel could not be created, pushed, or linked
 * \retval Reference to the channel on success
 */
static struct ast_channel *bridge_moh_create(struct ast_bridge *bridge)
{
    struct stasis_app_bridge_channel_wrapper *new_wrapper;
    struct ast_channel *chan;
    pthread_t threadid;
 
    chan = prepare_bridge_moh_channel();
    if (!chan) {
        return NULL;
    }
 
    if (stasis_app_channel_unreal_set_internal(chan)) {
        ast_hangup(chan);
        return NULL;
    }
 
    if (ast_unreal_channel_push_to_bridge(chan, bridge,
        AST_BRIDGE_CHANNEL_FLAG_IMMOVABLE | AST_BRIDGE_CHANNEL_FLAG_LONELY)) {
        ast_hangup(chan);
        return NULL;
    }
 
    new_wrapper = ao2_alloc_options(sizeof(*new_wrapper),
        stasis_app_bridge_channel_wrapper_destructor, AO2_ALLOC_OPT_LOCK_NOLOCK);
    if (!new_wrapper) {
        ast_hangup(chan);
        return NULL;
    }
 
    if (ast_string_field_init(new_wrapper, AST_UUID_STR_LEN + AST_CHANNEL_NAME)
        || ast_string_field_set(new_wrapper, bridge_id, bridge->uniqueid)
        || ast_string_field_set(new_wrapper, channel_id, ast_channel_uniqueid(chan))) {
        ao2_ref(new_wrapper, -1);
        ast_hangup(chan);
        return NULL;
    }
 
    if (!ao2_link_flags(app_bridges_moh, new_wrapper, OBJ_NOLOCK)) {
        ao2_ref(new_wrapper, -1);
        ast_hangup(chan);
        return NULL;
    }
 
    /* Pass the new_wrapper ref to moh_channel_thread() */
    if (ast_pthread_create_detached(&threadid, NULL, moh_channel_thread, new_wrapper)) {
        ast_log(LOG_ERROR, "Failed to create channel thread. Abandoning MOH channel creation.\n");
        ao2_unlink_flags(app_bridges_moh, new_wrapper, OBJ_NOLOCK);
        ao2_ref(new_wrapper, -1);
        ast_hangup(chan);
        return NULL;
    }
 
    return chan;
}
 
struct ast_channel *stasis_app_bridge_moh_channel(struct ast_bridge *bridge)
{
    struct ast_channel *chan;
    struct stasis_app_bridge_channel_wrapper *moh_wrapper;
 
    ao2_lock(app_bridges_moh);
    moh_wrapper = ao2_find(app_bridges_moh, bridge->uniqueid, OBJ_SEARCH_KEY | OBJ_NOLOCK);
    if (!moh_wrapper) {
        chan = bridge_moh_create(bridge);
    }
    ao2_unlock(app_bridges_moh);
 
    if (moh_wrapper) {
        chan = ast_channel_get_by_name(moh_wrapper->channel_id);
        ao2_ref(moh_wrapper, -1);
    }
 
    return chan;
}
 
int stasis_app_bridge_moh_stop(struct ast_bridge *bridge)
{
    struct stasis_app_bridge_channel_wrapper *moh_wrapper;
    struct ast_channel *chan;
 
    moh_wrapper = ao2_find(app_bridges_moh, bridge->uniqueid, OBJ_SEARCH_KEY | OBJ_UNLINK);
    if (!moh_wrapper) {
        return -1;
    }
 
    chan = ast_channel_get_by_name(moh_wrapper->channel_id);
    ao2_ref(moh_wrapper, -1);
    if (!chan) {
        return -1;
    }
 
    ast_moh_stop(chan);
    ast_softhangup(chan, AST_CAUSE_NORMAL_CLEARING);
    ao2_cleanup(chan);
 
    return 0;
}
 
/*! Removes the bridge to playback channel link */
static void remove_bridge_playback(char *bridge_id)
{
    struct stasis_app_bridge_channel_wrapper *wrapper;
    struct stasis_app_control *control;
 
    wrapper = ao2_find(app_bridges_playback, bridge_id, OBJ_SEARCH_KEY | OBJ_UNLINK);
 
    if (wrapper) {
        control = stasis_app_control_find_by_channel_id(wrapper->channel_id);
        if (control) {
            ao2_unlink(app_controls, control);
            ao2_ref(control, -1);
        }
        ao2_ref(wrapper, -1);
    }
    ast_free(bridge_id);
}
 
static void playback_after_bridge_cb_failed(enum ast_bridge_after_cb_reason reason, void *data)
{
    char *bridge_id = data;
 
    remove_bridge_playback(bridge_id);
}
 
static void playback_after_bridge_cb(struct ast_channel *chan, void *data)
{
    char *bridge_id = data;
 
    remove_bridge_playback(bridge_id);
}
 
int stasis_app_bridge_playback_channel_add(struct ast_bridge *bridge,
    struct ast_channel *chan,
    struct stasis_app_control *control)
{
    RAII_VAR(struct stasis_app_bridge_channel_wrapper *, new_wrapper, NULL, ao2_cleanup);
    char *bridge_id = ast_strdup(bridge->uniqueid);
 
    if (!bridge_id) {
        return -1;
    }
 
    if (ast_bridge_set_after_callback(chan,
        playback_after_bridge_cb, playback_after_bridge_cb_failed, bridge_id)) {
        ast_free(bridge_id);
        return -1;
    }
 
    new_wrapper = ao2_alloc_options(sizeof(*new_wrapper),
        stasis_app_bridge_channel_wrapper_destructor, AO2_ALLOC_OPT_LOCK_NOLOCK);
    if (!new_wrapper) {
        return -1;
    }
 
    if (ast_string_field_init(new_wrapper, 32)) {
        return -1;
    }
 
    ast_string_field_set(new_wrapper, bridge_id, bridge->uniqueid);
    ast_string_field_set(new_wrapper, channel_id, ast_channel_uniqueid(chan));
 
    if (!ao2_link(app_bridges_playback, new_wrapper)) {
        return -1;
    }
 
    ao2_link(app_controls, control);
    return 0;
}
 
void stasis_app_bridge_playback_channel_remove(char *bridge_id,
    struct stasis_app_control *control)
{
    struct stasis_app_bridge_channel_wrapper *wrapper;
 
    wrapper = ao2_find(app_bridges_playback, bridge_id, OBJ_SEARCH_KEY | OBJ_UNLINK);
    if (wrapper) {
        /* If wrapper is not found, then that means the after bridge callback has been
         * called or is in progress. No need to unlink the control here since that has
         * been done or is about to be done in the after bridge callback
         */
        ao2_unlink(app_controls, control);
        ao2_ref(wrapper, -1);
    }
}
 
struct ast_channel *stasis_app_bridge_playback_channel_find(struct ast_bridge *bridge)
{
    struct stasis_app_bridge_channel_wrapper *playback_wrapper;
    struct ast_channel *chan;
 
    playback_wrapper = ao2_find(app_bridges_playback, bridge->uniqueid, OBJ_SEARCH_KEY);
    if (!playback_wrapper) {
        return NULL;
    }
 
    chan = ast_channel_get_by_name(playback_wrapper->channel_id);
    ao2_ref(playback_wrapper, -1);
    return chan;
}
 
struct ast_bridge *stasis_app_bridge_find_by_id(
    const char *bridge_id)
{
    return ao2_find(app_bridges, bridge_id, OBJ_SEARCH_KEY);
}
 
 
/*!
 * \brief In addition to running ao2_cleanup(), this function also removes the
 * object from the app_controls container.
 */
static void control_unlink(struct stasis_app_control *control)
{
    if (!control) {
        return;
    }
 
    ao2_unlink(app_controls, control);
    ao2_cleanup(control);
}
 
static struct ast_bridge *bridge_create_common(const char *type, const char *name, const char *id, int invisible)
{
    struct ast_bridge *bridge;
    char *requested_type, *requested_types = ast_strdupa(S_OR(type, "mixing"));
    int capabilities = 0;
    int flags = AST_BRIDGE_FLAG_MERGE_INHIBIT_FROM | AST_BRIDGE_FLAG_MERGE_INHIBIT_TO
        | AST_BRIDGE_FLAG_SWAP_INHIBIT_FROM | AST_BRIDGE_FLAG_SWAP_INHIBIT_TO
        | AST_BRIDGE_FLAG_TRANSFER_BRIDGE_ONLY;
    enum ast_bridge_video_mode_type video_mode = AST_BRIDGE_VIDEO_MODE_TALKER_SRC;
    int send_sdp_label = 0;
 
    if (invisible) {
        flags |= AST_BRIDGE_FLAG_INVISIBLE;
    }
 
    while ((requested_type = strsep(&requested_types, ","))) {
        requested_type = ast_strip(requested_type);
 
        if (!strcmp(requested_type, "mixing")) {
            capabilities |= STASIS_BRIDGE_MIXING_CAPABILITIES;
            flags |= AST_BRIDGE_FLAG_SMART;
        } else if (!strcmp(requested_type, "holding")) {
            capabilities |= AST_BRIDGE_CAPABILITY_HOLDING;
        } else if (!strcmp(requested_type, "dtmf_events") ||
            !strcmp(requested_type, "proxy_media")) {
            capabilities &= ~AST_BRIDGE_CAPABILITY_NATIVE;
        } else if (!strcmp(requested_type, "video_sfu")) {
            video_mode = AST_BRIDGE_VIDEO_MODE_SFU;
        } else if (!strcmp(requested_type, "video_single")) {
            video_mode = AST_BRIDGE_VIDEO_MODE_SINGLE_SRC;
        } else if (!strcmp(requested_type, "sdp_label")) {
            send_sdp_label = 1;
        }
    }
 
    /* For an SFU video bridge we ensure it always remains in multimix for the best experience. */
    if (video_mode == AST_BRIDGE_VIDEO_MODE_SFU) {
        capabilities = AST_BRIDGE_CAPABILITY_MULTIMIX;
        flags &= ~AST_BRIDGE_FLAG_SMART;
    }
 
    if (!capabilities
        /* Holding and mixing capabilities don't mix. */
        || ((capabilities & AST_BRIDGE_CAPABILITY_HOLDING)
            && (capabilities & (STASIS_BRIDGE_MIXING_CAPABILITIES)))) {
        return NULL;
    }
 
    bridge = bridge_stasis_new(capabilities, flags, name, id, video_mode, send_sdp_label);
    if (bridge) {
        if (!ao2_link(app_bridges, bridge)) {
            ast_bridge_destroy(bridge, 0);
            bridge = NULL;
        }
    }
 
    return bridge;
}
 
struct ast_bridge *stasis_app_bridge_create(const char *type, const char *name, const char *id)
{
    return bridge_create_common(type, name, id, 0);
}
 
struct ast_bridge *stasis_app_bridge_create_invisible(const char *type, const char *name, const char *id)
{
    return bridge_create_common(type, name, id, 1);
}
 
void stasis_app_bridge_destroy(const char *bridge_id)
{
    struct ast_bridge *bridge = stasis_app_bridge_find_by_id(bridge_id);
    if (!bridge) {
        return;
    }
    ao2_unlink(app_bridges, bridge);
    ast_bridge_destroy(bridge, 0);
}
 
struct replace_channel_store {
    struct ast_channel_snapshot *snapshot;
    char *app;
};
 
static void replace_channel_destroy(void *obj)
{
    struct replace_channel_store *replace = obj;
 
    ao2_cleanup(replace->snapshot);
    ast_free(replace->app);
    ast_free(replace);
}
 
static const struct ast_datastore_info replace_channel_store_info = {
    .type = "replace-channel-store",
    .destroy = replace_channel_destroy,
};
 
static struct replace_channel_store *get_replace_channel_store(struct ast_channel *chan, int no_create)
{
    struct ast_datastore *datastore;
    struct replace_channel_store *ret;
 
    ast_channel_lock(chan);
    datastore = ast_channel_datastore_find(chan, &replace_channel_store_info, NULL);
    if (!datastore && !no_create) {
        datastore = ast_datastore_alloc(&replace_channel_store_info, NULL);
        if (datastore) {
            ast_channel_datastore_add(chan, datastore);
        }
    }
 
    if (!datastore) {
        ast_channel_unlock(chan);
        return NULL;
    }
 
    if (!datastore->data) {
        datastore->data = ast_calloc(1, sizeof(struct replace_channel_store));
    }
 
    ret = datastore->data;
    ast_channel_unlock(chan);
 
    return ret;
}
 
int app_set_replace_channel_snapshot(struct ast_channel *chan, struct ast_channel_snapshot *replace_snapshot)
{
    struct replace_channel_store *replace = get_replace_channel_store(chan, 0);
 
    if (!replace) {
        return -1;
    }
 
    ao2_replace(replace->snapshot, replace_snapshot);
    return 0;
}
 
int app_set_replace_channel_app(struct ast_channel *chan, const char *replace_app)
{
    struct replace_channel_store *replace = get_replace_channel_store(chan, 0);
 
    if (!replace) {
        return -1;
    }
 
    ast_free(replace->app);
    replace->app = NULL;
 
    if (replace_app) {
        replace->app = ast_strdup(replace_app);
        if (!replace->app) {
            return -1;
        }
    }
 
    return 0;
}
 
static struct ast_channel_snapshot *get_replace_channel_snapshot(struct ast_channel *chan)
{
    struct replace_channel_store *replace = get_replace_channel_store(chan, 1);
    struct ast_channel_snapshot *replace_channel_snapshot;
 
    if (!replace) {
        return NULL;
    }
 
    replace_channel_snapshot = replace->snapshot;
    replace->snapshot = NULL;
 
    return replace_channel_snapshot;
}
 
char *app_get_replace_channel_app(struct ast_channel *chan)
{
    struct replace_channel_store *replace = get_replace_channel_store(chan, 1);
    char *replace_channel_app;
 
    if (!replace) {
        return NULL;
    }
 
    replace_channel_app = replace->app;
    replace->app = NULL;
 
    return replace_channel_app;
}
 
static void start_message_blob_dtor(void *obj)
{
    struct start_message_blob *payload = obj;
 
    ao2_cleanup(payload->channel);
    ao2_cleanup(payload->replace_channel);
    ast_json_unref(payload->blob);
}
 
static int send_start_msg_snapshots(struct ast_channel *chan, struct stasis_app *app,
    int argc, char *argv[], struct ast_channel_snapshot *snapshot,
    struct ast_channel_snapshot *replace_channel_snapshot)
{
    struct ast_json *json_blob;
    struct ast_json *json_args;
    struct start_message_blob *payload;
    struct stasis_message *msg;
    int i;
 
    if (app_subscribe_channel(app, chan)) {
        ast_log(LOG_ERROR, "Error subscribing app '%s' to channel '%s'\n",
            stasis_app_name(app), ast_channel_name(chan));
        return -1;
    }
 
    payload = ao2_alloc(sizeof(*payload), start_message_blob_dtor);
    if (!payload) {
        ast_log(LOG_ERROR, "Error packing JSON for StasisStart message\n");
        return -1;
    }
 
    payload->channel = ao2_bump(snapshot);
    payload->replace_channel = ao2_bump(replace_channel_snapshot);
 
    json_blob = ast_json_pack("{s: s, s: o, s: []}",
        "app", stasis_app_name(app),
        "timestamp", ast_json_timeval(ast_tvnow(), NULL),
        "args");
    if (!json_blob) {
        ast_log(LOG_ERROR, "Error packing JSON for StasisStart message\n");
        ao2_ref(payload, -1);
        return -1;
    }
    payload->blob = json_blob;
 
 
    /* Append arguments to args array */
    json_args = ast_json_object_get(json_blob, "args");
    ast_assert(json_args != NULL);
    for (i = 0; i < argc; ++i) {
        int r = ast_json_array_append(json_args,
                          ast_json_string_create(argv[i]));
        if (r != 0) {
            ast_log(LOG_ERROR, "Error appending to StasisStart message\n");
            ao2_ref(payload, -1);
            return -1;
        }
    }
 
 
    msg = stasis_message_create(start_message_type(), payload);
    ao2_ref(payload, -1);
    if (!msg) {
        ast_log(LOG_ERROR, "Error sending StasisStart message\n");
        return -1;
    }
 
    if (replace_channel_snapshot) {
        app_unsubscribe_channel_id(app, replace_channel_snapshot->base->uniqueid);
    }
    stasis_publish(ast_app_get_topic(app), msg);
    ao2_ref(msg, -1);
    return 0;
}
 
static int send_start_msg(struct stasis_app *app, struct ast_channel *chan,
    int argc, char *argv[])
{
    int ret = -1;
    struct ast_channel_snapshot *snapshot;
    struct ast_channel_snapshot *replace_channel_snapshot;
 
    ast_assert(chan != NULL);
 
    replace_channel_snapshot = get_replace_channel_snapshot(chan);
 
    /* Set channel info */
    ast_channel_lock(chan);
    snapshot = ast_channel_snapshot_create(chan);
    ast_channel_unlock(chan);
    if (snapshot) {
        ret = send_start_msg_snapshots(chan, app, argc, argv, snapshot, replace_channel_snapshot);
        ao2_ref(snapshot, -1);
    }
    ao2_cleanup(replace_channel_snapshot);
 
    return ret;
}
 
static void remove_masquerade_store(struct ast_channel *chan);
 
int app_send_end_msg(struct stasis_app *app, struct ast_channel *chan)
{
    struct stasis_message_sanitizer *sanitize = stasis_app_get_sanitizer();
    struct ast_json *blob;
    struct stasis_message *msg;
 
    if (sanitize && sanitize->channel
        && sanitize->channel(chan)) {
        return 0;
    }
 
    blob = ast_json_pack("{s: s, s: o}",
        "app", stasis_app_name(app),
        "timestamp", ast_json_timeval(ast_tvnow(), NULL)
        );
    if (!blob) {
        ast_log(LOG_ERROR, "Error packing JSON for StasisEnd message\n");
        return -1;
    }
 
    remove_masquerade_store(chan);
    app_unsubscribe_channel(app, chan);
    msg = ast_channel_blob_create(chan, end_message_type(), blob);
    if (msg) {
        stasis_publish(ast_app_get_topic(app), msg);
    }
    ao2_cleanup(msg);
    ast_json_unref(blob);
 
    return 0;
}
 
static int masq_match_cb(void *obj, void *data, int flags)
{
    struct stasis_app_control *control = obj;
    struct ast_channel *chan = data;
 
    if (!strcmp(ast_channel_uniqueid(chan),
        stasis_app_control_get_channel_id(control))) {
        return CMP_MATCH;
    }
 
    return 0;
}
 
static void channel_stolen_cb(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan)
{
    struct stasis_app_control *control;
 
    /*
     * At this point, old_chan is the channel pointer that is in Stasis() and
     * has the unknown channel's name in it while new_chan is the channel pointer
     * that is not in Stasis(), but has the guts of the channel that Stasis() knows
     * about.
     *
     * Find and unlink control since the channel has a new name/uniqueid
     * and its hash has changed.  Since the channel is leaving stasis don't
     * bother putting it back into the container.  Nobody is going to
     * remove it from the container later.
     */
    control = ao2_callback(app_controls, OBJ_UNLINK, masq_match_cb, old_chan);
    if (!control) {
        ast_log(LOG_ERROR, "Could not find control for masqueraded channel\n");
        return;
    }
 
    /* send the StasisEnd message to the app */
    stasis_app_channel_set_stasis_end_published(new_chan);
    app_send_end_msg(control_app(control), new_chan);
 
    /* remove the datastore */
    remove_masquerade_store(old_chan);
 
    ao2_cleanup(control);
}
 
static void channel_replaced_cb(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan)
{
    RAII_VAR(struct ast_channel_snapshot *, new_snapshot, NULL, ao2_cleanup);
    RAII_VAR(struct ast_channel_snapshot *, old_snapshot, NULL, ao2_cleanup);
    struct stasis_app_control *control;
 
    /* At this point, new_chan is the channel pointer that is in Stasis() and
     * has the unknown channel's name in it while old_chan is the channel pointer
     * that is not in Stasis(), but has the guts of the channel that Stasis() knows
     * about */
 
    /* grab a snapshot for the channel that is jumping into Stasis() */
    new_snapshot = ast_channel_snapshot_get_latest(ast_channel_uniqueid(new_chan));
    if (!new_snapshot) {
        ast_log(LOG_ERROR, "Could not get snapshot for masquerading channel\n");
        return;
    }
 
    /* grab a snapshot for the channel that has been kicked out of Stasis() */
    old_snapshot = ast_channel_snapshot_get_latest(ast_channel_uniqueid(old_chan));
    if (!old_snapshot) {
        ast_log(LOG_ERROR, "Could not get snapshot for masqueraded channel\n");
        return;
    }
 
    /*
     * Find, unlink, and relink control since the channel has a new
     * name/uniqueid and its hash has changed.
     */
    control = ao2_callback(app_controls, OBJ_UNLINK, masq_match_cb, new_chan);
    if (!control) {
        ast_log(LOG_ERROR, "Could not find control for masquerading channel\n");
        return;
    }
    ao2_link(app_controls, control);
 
 
    /* send the StasisStart with replace_channel to the app */
    send_start_msg_snapshots(new_chan, control_app(control), 0, NULL, new_snapshot,
        old_snapshot);
    /* send the StasisEnd message to the app */
    app_send_end_msg(control_app(control), old_chan);
 
    ao2_cleanup(control);
}
 
static const struct ast_datastore_info masquerade_store_info = {
    .type = "stasis-masquerade",
    .chan_fixup = channel_stolen_cb,
    .chan_breakdown = channel_replaced_cb,
};
 
static int has_masquerade_store(struct ast_channel *chan)
{
    SCOPED_CHANNELLOCK(lock, chan);
    return !!ast_channel_datastore_find(chan, &masquerade_store_info, NULL);
}
 
static int add_masquerade_store(struct ast_channel *chan)
{
    struct ast_datastore *datastore;
 
    SCOPED_CHANNELLOCK(lock, chan);
    if (ast_channel_datastore_find(chan, &masquerade_store_info, NULL)) {
        return 0;
    }
 
    datastore = ast_datastore_alloc(&masquerade_store_info, NULL);
    if (!datastore) {
        return -1;
    }
 
    ast_channel_datastore_add(chan, datastore);
 
    return 0;
}
 
static void remove_masquerade_store(struct ast_channel *chan)
{
    struct ast_datastore *datastore;
 
    SCOPED_CHANNELLOCK(lock, chan);
    datastore = ast_channel_datastore_find(chan, &masquerade_store_info, NULL);
    if (!datastore) {
        return;
    }
 
    ast_channel_datastore_remove(chan, datastore);
    ast_datastore_free(datastore);
}
 
void stasis_app_control_execute_until_exhausted(struct ast_channel *chan, struct stasis_app_control *control)
{
    while (!control_is_done(control)) {
        int command_count;
        command_count = control_dispatch_all(control, chan);
 
        ao2_lock(control);
 
        if (control_command_count(control)) {
            /* If the command queue isn't empty, something added to the queue before it was locked. */
            ao2_unlock(control);
            continue;
        }
 
        if (command_count == 0 || ast_channel_fdno(chan) == -1) {
            control_mark_done(control);
            ao2_unlock(control);
            break;
        }
        ao2_unlock(control);
    }
}
 
int stasis_app_control_is_done(struct stasis_app_control *control)
{
    return control_is_done(control);
}
 
void stasis_app_control_flush_queue(struct stasis_app_control *control)
{
    control_flush_queue(control);
}
 
struct ast_datastore_info set_end_published_info = {
    .type = "stasis_end_published",
};
 
void stasis_app_channel_set_stasis_end_published(struct ast_channel *chan)
{
    struct ast_datastore *datastore;
 
    datastore = ast_datastore_alloc(&set_end_published_info, NULL);
    if (datastore) {
        ast_channel_lock(chan);
        ast_channel_datastore_add(chan, datastore);
        ast_channel_unlock(chan);
    }
}
 
int stasis_app_channel_is_stasis_end_published(struct ast_channel *chan)
{
    struct ast_datastore *datastore;
 
    ast_channel_lock(chan);
    datastore = ast_channel_datastore_find(chan, &set_end_published_info, NULL);
    ast_channel_unlock(chan);
 
    return datastore ? 1 : 0;
}
 
static void remove_stasis_end_published(struct ast_channel *chan)
{
    struct ast_datastore *datastore;
 
    ast_channel_lock(chan);
    datastore = ast_channel_datastore_find(chan, &set_end_published_info, NULL);
    if (datastore) {
        ast_channel_datastore_remove(chan, datastore);
        ast_datastore_free(datastore);
    }
    ast_channel_unlock(chan);
}
 
/*! \brief Stasis dialplan application callback */
int stasis_app_exec(struct ast_channel *chan, const char *app_name, int argc,
            char *argv[])
{
    RAII_VAR(struct stasis_app *, app, NULL, ao2_cleanup);
    RAII_VAR(struct stasis_app_control *, control, NULL, control_unlink);
    struct ast_bridge *bridge = NULL;
    int res = 0;
    int needs_depart;
 
    ast_assert(chan != NULL);
 
    /* Just in case there's a lingering indication that the channel has had a stasis
     * end published on it, remove that now.
     */
    remove_stasis_end_published(chan);
 
    if (!apps_registry) {
        return -1;
    }
 
    app = ao2_find(apps_registry, app_name, OBJ_SEARCH_KEY);
    if (!app) {
        ast_log(LOG_ERROR,
            "Stasis app '%s' not registered\n", app_name);
        return -1;
    }
    if (!app_is_active(app)) {
        ast_log(LOG_ERROR,
            "Stasis app '%s' not active\n", app_name);
        return -1;
    }
 
    control = control_create(chan, app);
    if (!control) {
        ast_log(LOG_ERROR, "Control allocation failed or Stasis app '%s' not registered\n", app_name);
        return -1;
    }
 
    if (!control_app(control)) {
        ast_log(LOG_ERROR, "Stasis app '%s' not registered\n", app_name);
        return -1;
    }
 
    if (!app_is_active(control_app(control))) {
        ast_log(LOG_ERROR, "Stasis app '%s' not active\n", app_name);
        return -1;
    }
    ao2_link(app_controls, control);
 
    if (add_masquerade_store(chan)) {
        ast_log(LOG_ERROR, "Failed to attach masquerade detector\n");
        return -1;
    }
 
    res = send_start_msg(control_app(control), chan, argc, argv);
    if (res != 0) {
        ast_log(LOG_ERROR,
            "Error sending start message to '%s'\n", app_name);
        remove_masquerade_store(chan);
        return -1;
    }
 
    /* Pull queued prestart commands and execute */
    control_prestart_dispatch_all(control, chan);
 
    while (!control_is_done(control)) {
        RAII_VAR(struct ast_frame *, f, NULL, ast_frame_dtor);
        int r;
        int command_count;
        RAII_VAR(struct ast_bridge *, last_bridge, NULL, ao2_cleanup);
 
        /* Check to see if a bridge absorbed our hangup frame */
        if (ast_check_hangup_locked(chan)) {
            control_mark_done(control);
            break;
        }
 
        /* control->next_app is only modified within the control thread, so this is safe */
        if (control_next_app(control)) {
            struct stasis_app *next_app = ao2_find(apps_registry, control_next_app(control), OBJ_SEARCH_KEY);
 
            if (next_app && app_is_active(next_app)) {
                int idx;
                int next_argc;
                char **next_argv;
 
                /* If something goes wrong in this conditional, res will need to be non-zero
                 * so that the code below the exec loop knows something went wrong during a move.
                 */
                if (!stasis_app_channel_is_stasis_end_published(chan)) {
                    res = has_masquerade_store(chan) && app_send_end_msg(control_app(control), chan);
                    if (res != 0) {
                        ast_log(LOG_ERROR,
                            "Error sending end message to %s\n", stasis_app_name(control_app(control)));
                        control_mark_done(control);
                        ao2_ref(next_app, -1);
                        break;
                    }
                } else {
                    remove_stasis_end_published(chan);
                }
 
                /* This will ao2_bump next_app, and unref the previous app by 1 */
                control_set_app(control, next_app);
 
                /* There's a chance that the previous application is ready for clean up, so go ahead
                 * and do that now.
                 */
                cleanup();
 
                /* We need to add another masquerade store, otherwise the leave message will
                 * not show up for the correct application.
                 */
                if (add_masquerade_store(chan)) {
                    ast_log(LOG_ERROR, "Failed to attach masquerade detector\n");
                    res = -1;
                    control_mark_done(control);
                    ao2_ref(next_app, -1);
                    break;
                }
 
                /* We MUST get the size before the list, as control_next_app_args steals the elements
                 * from the string vector.
                 */
                next_argc = control_next_app_args_size(control);
                next_argv = control_next_app_args(control);
 
                res = send_start_msg(control_app(control), chan, next_argc, next_argv);
 
                /* Even if res != 0, we still need to free the memory we got from control_argv */
                if (next_argv) {
                    for (idx = 0; idx < next_argc; idx++) {
                        ast_free(next_argv[idx]);
                    }
                    ast_free(next_argv);
                }
 
                if (res != 0) {
                    ast_log(LOG_ERROR,
                        "Error sending start message to '%s'\n", stasis_app_name(control_app(control)));
                    remove_masquerade_store(chan);
                    control_mark_done(control);
                    ao2_ref(next_app, -1);
                    break;
                }
 
                /* Done switching applications, free memory and clean up */
                control_move_cleanup(control);
            } else {
                /* If we can't switch applications, do nothing */
                struct ast_json *msg;
                RAII_VAR(struct ast_channel_snapshot *, snapshot, NULL, ao2_cleanup);
 
                if (!next_app) {
                    ast_log(LOG_ERROR, "Could not move to Stasis app '%s' - not registered\n",
                        control_next_app(control));
                } else {
                    ast_log(LOG_ERROR, "Could not move to Stasis app '%s' - not active\n",
                        control_next_app(control));
                }
 
                snapshot = ast_channel_snapshot_get_latest(ast_channel_uniqueid(chan));
                if (!snapshot) {
                    ast_log(LOG_ERROR, "Could not get channel shapshot for '%s'\n",
                        ast_channel_name(chan));
                } else {
                    struct ast_json *json_args;
                    int next_argc = control_next_app_args_size(control);
                    char **next_argv = control_next_app_args(control);
 
                    msg = ast_json_pack("{s: s, s: o, s: o, s: s, s: []}",
                        "type", "ApplicationMoveFailed",
                        "timestamp", ast_json_timeval(ast_tvnow(), NULL),
                        "channel", ast_channel_snapshot_to_json(snapshot, NULL),
                        "destination", control_next_app(control),
                        "args");
                    if (!msg) {
                        ast_log(LOG_ERROR, "Failed to pack JSON for ApplicationMoveFailed message\n");
                    } else {
                        json_args = ast_json_object_get(msg, "args");
                        if (!json_args) {
                            ast_log(LOG_ERROR, "Could not get args json array");
                        } else {
                            int r = 0;
                            int idx;
                            for (idx = 0; idx < next_argc; ++idx) {
                                r = ast_json_array_append(json_args,
                                    ast_json_string_create(next_argv[idx]));
                                if (r != 0) {
                                    ast_log(LOG_ERROR, "Error appending to ApplicationMoveFailed message\n");
                                    break;
                                }
                            }
                            if (r == 0) {
                                app_send(control_app(control), msg);
                            }
                        }
                        ast_json_unref(msg);
                    }
                }
            }
            control_move_cleanup(control);
            ao2_cleanup(next_app);
        }
 
        last_bridge = bridge;
        bridge = ao2_bump(stasis_app_get_bridge(control));
 
        if (bridge != last_bridge) {
            if (last_bridge) {
                app_unsubscribe_bridge(control_app(control), last_bridge);
            }
            if (bridge) {
                app_subscribe_bridge(control_app(control), bridge);
            }
        }
 
        if (bridge) {
            /* Bridge/dial is handling channel frames */
            control_wait(control);
            control_dispatch_all(control, chan);
            continue;
        }
 
        r = ast_waitfor(chan, MAX_WAIT_MS);
 
        if (r < 0) {
            ast_debug(3, "%s: Poll error\n",
                  ast_channel_uniqueid(chan));
            control_mark_done(control);
            break;
        }
 
        command_count = control_dispatch_all(control, chan);
 
        if (command_count > 0 && ast_channel_fdno(chan) == -1) {
            /* Command drained the channel; wait for next frame */
            continue;
        }
 
        if (r == 0) {
            /* Timeout */
            continue;
        }
 
        f = ast_read(chan);
        if (!f) {
            /* Continue on in the dialplan */
            ast_debug(3, "%s: Hangup (no more frames)\n",
                ast_channel_uniqueid(chan));
            control_mark_done(control);
            break;
        }
 
        if (f->frametype == AST_FRAME_CONTROL) {
            if (f->subclass.integer == AST_CONTROL_HANGUP) {
                /* Continue on in the dialplan */
                ast_debug(3, "%s: Hangup\n",
                    ast_channel_uniqueid(chan));
                control_mark_done(control);
                break;
            }
        }
    }
 
    ast_channel_lock(chan);
    needs_depart = (ast_channel_internal_bridge_channel(chan) != NULL);
    ast_channel_unlock(chan);
    if (needs_depart) {
        ast_bridge_depart(chan);
    }
 
    if (stasis_app_get_bridge(control)) {
        app_unsubscribe_bridge(control_app(control), stasis_app_get_bridge(control));
    }
    ao2_cleanup(bridge);
 
    /* Only publish a stasis_end event if it hasn't already been published */
    if (!res && !stasis_app_channel_is_stasis_end_published(chan)) {
        /* A masquerade has occurred and this message will be wrong so it
         * has already been sent elsewhere. */
        res = has_masquerade_store(chan) && app_send_end_msg(control_app(control), chan);
        if (res != 0) {
            ast_log(LOG_ERROR,
                "Error sending end message to %s\n", stasis_app_name(control_app(control)));
            return res;
        }
    } else {
        remove_stasis_end_published(chan);
    }
 
    control_flush_queue(control);
 
    /* Stop any lingering silence generator */
    control_silence_stop_now(control);
 
    /* There's an off chance that app is ready for cleanup. Go ahead
     * and clean up, just in case
     */
    cleanup();
 
    /* The control needs to be removed from the controls container in
     * case a new PBX is started and ends up coming back into Stasis.
     */
    control_unlink(control);
    control = NULL;
 
    if (!res && !ast_channel_pbx(chan)) {
        int chan_hungup;
 
        /* The ASYNCGOTO softhangup flag may have broken the channel out of
         * its bridge to run dialplan, so if there's no pbx on the channel
         * let it run dialplan here. Otherwise, it will run when this
         * application exits. */
        ast_channel_lock(chan);
        ast_channel_clear_softhangup(chan, AST_SOFTHANGUP_ASYNCGOTO);
        chan_hungup = ast_check_hangup(chan);
        ast_channel_unlock(chan);
 
        if (!chan_hungup) {
            struct ast_pbx_args pbx_args;
 
            memset(&pbx_args, 0, sizeof(pbx_args));
            pbx_args.no_hangup_chan = 1;
 
            res = ast_pbx_run_args(chan, &pbx_args);
        }
    }
 
    return res;
}
 
int stasis_app_send(const char *app_name, struct ast_json *message)
{
    struct stasis_app *app;
 
    if (!apps_registry) {
        return -1;
    }
 
    app = ao2_find(apps_registry, app_name, OBJ_SEARCH_KEY);
    if (!app) {
        /* XXX We can do a better job handling late binding, queueing up
         * the call for a few seconds to wait for the app to register.
         */
        ast_log(LOG_WARNING,
            "Stasis app '%s' not registered\n", app_name);
        return -1;
    }
    app_send(app, message);
    ao2_ref(app, -1);
 
    return 0;
}
 
static struct stasis_app *find_app_by_name(const char *app_name)
{
    struct stasis_app *res = NULL;
 
    if (!apps_registry) {
        return NULL;
    }
 
    if (!ast_strlen_zero(app_name)) {
        res = ao2_find(apps_registry, app_name, OBJ_SEARCH_KEY);
    }
 
    return res;
}
 
struct stasis_app *stasis_app_get_by_name(const char *name)
{
    return find_app_by_name(name);
}
 
static int append_name(void *obj, void *arg, int flags)
{
    struct stasis_app *app = obj;
    struct ao2_container *apps = arg;
 
    ast_str_container_add(apps, stasis_app_name(app));
    return 0;
}
 
struct ao2_container *stasis_app_get_all(void)
{
    struct ao2_container *apps;
 
    if (!apps_registry) {
        return NULL;
    }
 
    apps = ast_str_container_alloc(1);
    if (!apps) {
        return NULL;
    }
 
    ao2_callback(apps_registry, OBJ_NODATA, append_name, apps);
 
    return apps;
}
 
static int __stasis_app_register(const char *app_name, stasis_app_cb handler, void *data, int all_events)
{
    RAII_VAR(struct stasis_app *, app, NULL, ao2_cleanup);
 
    if (!apps_registry) {
        return -1;
    }
 
    ao2_lock(apps_registry);
    app = ao2_find(apps_registry, app_name, OBJ_SEARCH_KEY | OBJ_NOLOCK);
    if (app) {
        /*
         * We need to unlock the apps_registry before calling app_update to
         * prevent the possibility of a deadlock with the session.
         */
        ao2_unlock(apps_registry);
        app_update(app, handler, data);
        cleanup();
        return 0;
    }
 
    app = app_create(app_name, handler, data, all_events ? STASIS_APP_SUBSCRIBE_ALL : STASIS_APP_SUBSCRIBE_MANUAL);
    if (!app) {
        ao2_unlock(apps_registry);
        return -1;
    }
 
    if (all_events) {
        struct stasis_app_event_source *source;
 
        AST_RWLIST_RDLOCK(&event_sources);
        AST_LIST_TRAVERSE(&event_sources, source, next) {
            if (!source->subscribe) {
                continue;
            }
 
            source->subscribe(app, NULL);
        }
        AST_RWLIST_UNLOCK(&event_sources);
    }
    ao2_link_flags(apps_registry, app, OBJ_NOLOCK);
 
    ao2_unlock(apps_registry);
 
    /* We lazily clean up the apps_registry, because it's good enough to
     * prevent memory leaks, and we're lazy.
     */
    cleanup();
    return 0;
}
 
int stasis_app_register(const char *app_name, stasis_app_cb handler, void *data)
{
    return __stasis_app_register(app_name, handler, data, 0);
}
 
int stasis_app_register_all(const char *app_name, stasis_app_cb handler, void *data)
{
    return __stasis_app_register(app_name, handler, data, 1);
}
 
void stasis_app_unregister(const char *app_name)
{
    struct stasis_app *app;
 
    if (!app_name) {
        return;
    }
 
    if (!apps_registry) {
        return;
    }
 
    app = ao2_find(apps_registry, app_name, OBJ_SEARCH_KEY);
    if (!app) {
        ast_log(LOG_ERROR,
            "Stasis app '%s' not registered\n", app_name);
        return;
    }
 
    app_deactivate(app);
 
    /* There's a decent chance that app is ready for cleanup. Go ahead
     * and clean up, just in case
     */
    cleanup();
 
    ao2_ref(app, -1);
}
 
void stasis_app_register_event_source(struct stasis_app_event_source *obj)
{
    AST_RWLIST_WRLOCK(&event_sources);
    AST_LIST_INSERT_TAIL(&event_sources, obj, next);
    AST_RWLIST_UNLOCK(&event_sources);
}
 
void stasis_app_unregister_event_source(struct stasis_app_event_source *obj)
{
    struct stasis_app_event_source *source;
 
    AST_RWLIST_WRLOCK(&event_sources);
    AST_RWLIST_TRAVERSE_SAFE_BEGIN(&event_sources, source, next) {
        if (source == obj) {
            AST_RWLIST_REMOVE_CURRENT(next);
            break;
        }
    }
    AST_RWLIST_TRAVERSE_SAFE_END;
    AST_RWLIST_UNLOCK(&event_sources);
}
 
/*!
 * \internal
 * \brief Convert event source data to JSON.
 *
 * Calls each event source that has a "to_json" handler allowing each
 * source to add data to the given JSON object.
 *
 * \param app application associated with the event source
 * \param json a json object to "fill"
 *
 * \retval The given json object.
 */
static struct ast_json *app_event_sources_to_json(
    const struct stasis_app *app, struct ast_json *json)
{
    struct stasis_app_event_source *source;
 
    AST_RWLIST_RDLOCK(&event_sources);
    AST_LIST_TRAVERSE(&event_sources, source, next) {
        if (source->to_json) {
            source->to_json(app, json);
        }
    }
    AST_RWLIST_UNLOCK(&event_sources);
 
    return json;
}
 
struct ast_json *stasis_app_object_to_json(struct stasis_app *app)
{
    if (!app) {
        return NULL;
    }
 
    return stasis_app_event_filter_to_json(
        app, app_event_sources_to_json(app, app_to_json(app)));
}
 
struct ast_json *stasis_app_to_json(const char *app_name)
{
    struct stasis_app *app = find_app_by_name(app_name);
    struct ast_json *json = stasis_app_object_to_json(app);
 
    ao2_cleanup(app);
 
    return json;
}
 
/*!
 * \internal
 * \brief Finds an event source that matches a uri scheme.
 *
 * Uri(s) should begin with a particular scheme that can be matched
 * against an event source.
 *
 * \param uri uri containing a scheme to match
 *
 * \retval an event source if found, NULL otherwise.
 */
static struct stasis_app_event_source *app_event_source_find(const char *uri)
{
    struct stasis_app_event_source *source;
 
    AST_RWLIST_RDLOCK(&event_sources);
    AST_LIST_TRAVERSE(&event_sources, source, next) {
        if (ast_begins_with(uri, source->scheme)) {
            break;
        }
    }
    AST_RWLIST_UNLOCK(&event_sources);
 
    return source;
}
 
/*!
 * \internal
 * \brief Callback for subscription handling
 *
 * \param app [un]subscribing application
 * \param uri scheme:id of an event source
 * \param event_source being [un]subscribed [from]to
 *
 * \retval stasis_app_subscribe_res return code.
 */
typedef enum stasis_app_subscribe_res (*app_subscription_handler)(
    struct stasis_app *app, const char *uri,
    struct stasis_app_event_source *event_source);
 
/*!
 * \internal
 * \brief Subscriptions handler for application [un]subscribing.
 *
 * \param app_name Name of the application to subscribe.
 * \param event_source_uris URIs for the event sources to subscribe to.
 * \param event_sources_count Array size of event_source_uris.
 * \param json Optional output pointer for JSON representation of the app
 *             after adding the subscription.
 * \param handler [un]subscribe handler
 *
 * \retval stasis_app_subscribe_res return code.
 */
static enum stasis_app_subscribe_res app_handle_subscriptions(
    const char *app_name, const char **event_source_uris,
    int event_sources_count, struct ast_json **json,
    app_subscription_handler handler)
{
    struct stasis_app *app = find_app_by_name(app_name);
    int i;
 
    ast_assert(handler != NULL);
 
    if (!app) {
        return STASIS_ASR_APP_NOT_FOUND;
    }
 
    for (i = 0; i < event_sources_count; ++i) {
        const char *uri = event_source_uris[i];
        struct stasis_app_event_source *event_source;
        enum stasis_app_subscribe_res res;
 
        event_source = app_event_source_find(uri);
        if (!event_source) {
            ast_log(LOG_WARNING, "Invalid scheme: %s\n", uri);
            ao2_ref(app, -1);
 
            return STASIS_ASR_EVENT_SOURCE_BAD_SCHEME;
        }
 
        res = handler(app, uri, event_source);
        if (res != STASIS_ASR_OK) {
            ao2_ref(app, -1);
 
            return res;
        }
    }
 
    if (json) {
        ast_debug(3, "%s: Successful; setting results\n", app_name);
        *json = stasis_app_object_to_json(app);
    }
 
    ao2_ref(app, -1);
 
    return STASIS_ASR_OK;
}
 
enum stasis_app_subscribe_res stasis_app_subscribe_channel(const char *app_name,
    struct ast_channel *chan)
{
    struct stasis_app *app = find_app_by_name(app_name);
    int res;
 
    if (!app) {
        return STASIS_ASR_APP_NOT_FOUND;
    }
 
    ast_debug(3, "%s: Subscribing to %s\n", app_name, ast_channel_uniqueid(chan));
 
    res = app_subscribe_channel(app, chan);
    ao2_ref(app, -1);
 
    if (res != 0) {
        ast_log(LOG_ERROR, "Error subscribing app '%s' to channel '%s'\n",
            app_name, ast_channel_uniqueid(chan));
        return STASIS_ASR_INTERNAL_ERROR;
    }
 
    return STASIS_ASR_OK;
}
 
 
/*!
 * \internal
 * \brief Subscribe an app to an event source.
 *
 * \param app subscribing application
 * \param uri scheme:id of an event source
 * \param event_source being subscribed to
 *
 * \retval stasis_app_subscribe_res return code.
 */
static enum stasis_app_subscribe_res app_subscribe(
    struct stasis_app *app, const char *uri,
    struct stasis_app_event_source *event_source)
{
    const char *app_name = stasis_app_name(app);
    RAII_VAR(void *, obj, NULL, ao2_cleanup);
 
    ast_debug(3, "%s: Checking %s\n", app_name, uri);
 
    if (!ast_strlen_zero(uri + strlen(event_source->scheme)) &&
        (!event_source->find || (!(obj = event_source->find(app, uri + strlen(event_source->scheme)))))) {
        ast_log(LOG_WARNING, "Event source not found: %s\n", uri);
        return STASIS_ASR_EVENT_SOURCE_NOT_FOUND;
    }
 
    ast_debug(3, "%s: Subscribing to %s\n", app_name, uri);
 
    if (!event_source->subscribe || (event_source->subscribe(app, obj))) {
        ast_log(LOG_WARNING, "Error subscribing app '%s' to '%s'\n",
            app_name, uri);
        return STASIS_ASR_INTERNAL_ERROR;
    }
 
    return STASIS_ASR_OK;
}
 
enum stasis_app_subscribe_res stasis_app_subscribe(const char *app_name,
    const char **event_source_uris, int event_sources_count,
    struct ast_json **json)
{
    return app_handle_subscriptions(
        app_name, event_source_uris, event_sources_count,
        json, app_subscribe);
}
 
/*!
 * \internal
 * \brief Unsubscribe an app from an event source.
 *
 * \param app application to unsubscribe
 * \param uri scheme:id of an event source
 * \param event_source being unsubscribed from
 *
 * \retval stasis_app_subscribe_res return code.
 */
static enum stasis_app_subscribe_res app_unsubscribe(
    struct stasis_app *app, const char *uri,
    struct stasis_app_event_source *event_source)
{
    const char *app_name = stasis_app_name(app);
    const char *id = uri + strlen(event_source->scheme);
 
    if (!event_source->is_subscribed ||
        (!event_source->is_subscribed(app, id))) {
        return STASIS_ASR_EVENT_SOURCE_NOT_FOUND;
    }
 
    ast_debug(3, "%s: Unsubscribing from %s\n", app_name, uri);
 
    if (!event_source->unsubscribe || (event_source->unsubscribe(app, id))) {
        ast_log(LOG_WARNING, "Error unsubscribing app '%s' to '%s'\n",
            app_name, uri);
        return -1;
    }
    return 0;
}
 
enum stasis_app_subscribe_res stasis_app_unsubscribe(const char *app_name,
    const char **event_source_uris, int event_sources_count,
    struct ast_json **json)
{
    return app_handle_subscriptions(
        app_name, event_source_uris, event_sources_count,
        json, app_unsubscribe);
}
 
enum stasis_app_user_event_res stasis_app_user_event(const char *app_name,
    const char *event_name,
    const char **source_uris, int sources_count,
    struct ast_json *json_variables)
{
    RAII_VAR(struct stasis_app *, app, find_app_by_name(app_name), ao2_cleanup);
    struct ast_json *blob = NULL;
    struct ast_multi_object_blob *multi;
    struct stasis_message *message;
    enum stasis_app_user_event_res res = STASIS_APP_USER_INTERNAL_ERROR;
    int have_channel = 0;
    int i;
 
    if (!app) {
        ast_log(LOG_WARNING, "App %s not found\n", app_name);
        return STASIS_APP_USER_APP_NOT_FOUND;
    }
 
    if (!ast_multi_user_event_type()) {
        return res;
    }
 
    if (json_variables) {
        struct ast_json *json_value = ast_json_string_create(event_name);
 
        if (json_value && !ast_json_object_set(json_variables, "eventname", json_value)) {
            blob = ast_json_ref(json_variables);
        }
    } else {
        blob = ast_json_pack("{s: s}", "eventname", event_name);
    }
 
    if (!blob) {
        ast_log(LOG_ERROR, "Failed to initialize blob\n");
 
        return res;
    }
 
    multi = ast_multi_object_blob_create(blob);
    ast_json_unref(blob);
    if (!multi) {
        ast_log(LOG_ERROR, "Failed to initialize multi\n");
 
        return res;
    }
 
    for (i = 0; i < sources_count; ++i) {
        const char *uri = source_uris[i];
        void *snapshot=NULL;
        enum stasis_user_multi_object_snapshot_type type;
 
        if (ast_begins_with(uri, "channel:")) {
            type = STASIS_UMOS_CHANNEL;
            snapshot = ast_channel_snapshot_get_latest(uri + 8);
            have_channel = 1;
        } else if (ast_begins_with(uri, "bridge:")) {
            type = STASIS_UMOS_BRIDGE;
            snapshot = ast_bridge_get_snapshot_by_uniqueid(uri + 7);
        } else if (ast_begins_with(uri, "endpoint:")) {
            type = STASIS_UMOS_ENDPOINT;
            snapshot = ast_endpoint_latest_snapshot(uri + 9, NULL);
        } else {
            ast_log(LOG_WARNING, "Invalid scheme: %s\n", uri);
            ao2_ref(multi, -1);
 
            return STASIS_APP_USER_EVENT_SOURCE_BAD_SCHEME;
        }
        if (!snapshot) {
            ast_log(LOG_ERROR, "Unable to get snapshot for %s\n", uri);
            ao2_ref(multi, -1);
 
            return STASIS_APP_USER_EVENT_SOURCE_NOT_FOUND;
        }
        ast_multi_object_blob_add(multi, type, snapshot);
    }
 
    message = stasis_message_create(ast_multi_user_event_type(), multi);
    ao2_ref(multi, -1);
 
    if (!message) {
        ast_log(LOG_ERROR, "Unable to create stasis user event message\n");
        return res;
    }
 
    /*
     * Publishing to two different topics is normally to be avoided -- except
     * in this case both are final destinations with no forwards (only listeners).
     * The message has to be delivered to the application topic for ARI, but a
     * copy is also delivered directly to the manager for AMI if there is a channel.
     */
    stasis_publish(ast_app_get_topic(app), message);
 
    if (have_channel) {
        stasis_publish(ast_manager_get_topic(), message);
    }
    ao2_ref(message, -1);
 
    return STASIS_APP_USER_OK;
}
 
static int unload_module(void)
{
    stasis_app_unregister_event_sources();
 
    messaging_cleanup();
 
    cleanup();
 
    stasis_app_control_shutdown();
 
    ao2_cleanup(apps_registry);
    apps_registry = NULL;
 
    ao2_cleanup(app_controls);
    app_controls = NULL;
 
    ao2_cleanup(app_bridges);
    app_bridges = NULL;
 
    ao2_cleanup(app_bridges_moh);
    app_bridges_moh = NULL;
 
    ao2_cleanup(app_bridges_playback);
    app_bridges_playback = NULL;
 
    STASIS_MESSAGE_TYPE_CLEANUP(end_message_type);
    STASIS_MESSAGE_TYPE_CLEANUP(start_message_type);
 
    return 0;
}
 
/*! \brief Sanitization callback for channel snapshots */
static int channel_snapshot_sanitizer(const struct ast_channel_snapshot *snapshot)
{
    if (!snapshot || !(snapshot->base->tech_properties & AST_CHAN_TP_INTERNAL)) {
        return 0;
    }
    return 1;
}
 
/*! \brief Sanitization callback for channels */
static int channel_sanitizer(const struct ast_channel *chan)
{
    if (!chan || !(ast_channel_tech(chan)->properties & AST_CHAN_TP_INTERNAL)) {
        return 0;
    }
    return 1;
}
 
/*! \brief Sanitization callback for channel unique IDs */
static int channel_id_sanitizer(const char *id)
{
    struct ast_channel_snapshot *snapshot;
    int ret;
 
    snapshot = ast_channel_snapshot_get_latest(id);
    ret = channel_snapshot_sanitizer(snapshot);
    ao2_cleanup(snapshot);
 
    return ret;
}
 
/*! \brief Sanitization callbacks for communication to Stasis applications */
struct stasis_message_sanitizer app_sanitizer = {
    .channel_id = channel_id_sanitizer,
    .channel_snapshot = channel_snapshot_sanitizer,
    .channel = channel_sanitizer,
};
 
struct stasis_message_sanitizer *stasis_app_get_sanitizer(void)
{
    return &app_sanitizer;
}
 
static const struct ast_datastore_info stasis_internal_channel_info = {
    .type = "stasis-internal-channel",
};
 
static int set_internal_datastore(struct ast_channel *chan)
{
    struct ast_datastore *datastore;
 
    datastore = ast_channel_datastore_find(chan, &stasis_internal_channel_info, NULL);
    if (!datastore) {
        datastore = ast_datastore_alloc(&stasis_internal_channel_info, NULL);
        if (!datastore) {
            return -1;
        }
        ast_channel_datastore_add(chan, datastore);
    }
    return 0;
}
 
int stasis_app_channel_unreal_set_internal(struct ast_channel *chan)
{
    struct ast_channel *outchan = NULL, *outowner = NULL;
    int res = 0;
    struct ast_unreal_pvt *unreal_pvt = ast_channel_tech_pvt(chan);
 
    ao2_ref(unreal_pvt, +1);
    ast_unreal_lock_all(unreal_pvt, &outowner, &outchan);
    if (outowner) {
        res |= set_internal_datastore(outowner);
        ast_channel_unlock(outowner);
        ast_channel_unref(outowner);
    }
    if (outchan) {
        res |= set_internal_datastore(outchan);
        ast_channel_unlock(outchan);
        ast_channel_unref(outchan);
    }
    ao2_unlock(unreal_pvt);
    ao2_ref(unreal_pvt, -1);
    return res;
}
 
int stasis_app_channel_set_internal(struct ast_channel *chan)
{
    int res;
 
    ast_channel_lock(chan);
    res = set_internal_datastore(chan);
    ast_channel_unlock(chan);
 
    return res;
}
 
int stasis_app_channel_is_internal(struct ast_channel *chan)
{
    struct ast_datastore *datastore;
    int res = 0;
 
    ast_channel_lock(chan);
    datastore = ast_channel_datastore_find(chan, &stasis_internal_channel_info, NULL);
    if (datastore) {
        res = 1;
    }
    ast_channel_unlock(chan);
 
    return res;
}
 
static int load_module(void)
{
    if (STASIS_MESSAGE_TYPE_INIT(start_message_type) != 0) {
        return AST_MODULE_LOAD_DECLINE;
    }
    if (STASIS_MESSAGE_TYPE_INIT(end_message_type) != 0) {
        return AST_MODULE_LOAD_DECLINE;
    }
    apps_registry = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
        APPS_NUM_BUCKETS, app_hash, NULL, app_compare);
    app_controls = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
        CONTROLS_NUM_BUCKETS, control_hash, NULL, control_compare);
    app_bridges = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0,
        BRIDGES_NUM_BUCKETS, bridges_hash, NULL, bridges_compare);
    app_bridges_moh = ao2_container_alloc_hash(
        AO2_ALLOC_OPT_LOCK_MUTEX, 0,
        37, bridges_channel_hash_fn, NULL, bridges_channel_compare);
    app_bridges_playback = ao2_container_alloc_hash(
        AO2_ALLOC_OPT_LOCK_MUTEX, AO2_CONTAINER_ALLOC_OPT_DUPS_REJECT,
        37, bridges_channel_hash_fn, bridges_channel_sort_fn, NULL);
    if (!apps_registry || !app_controls || !app_bridges || !app_bridges_moh || !app_bridges_playback) {
        unload_module();
        return AST_MODULE_LOAD_DECLINE;
    }
 
    if (messaging_init()) {
        unload_module();
        return AST_MODULE_LOAD_DECLINE;
    }
 
    bridge_stasis_init();
 
    stasis_app_register_event_sources();
 
    return AST_MODULE_LOAD_SUCCESS;
}
 
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS | AST_MODFLAG_LOAD_ORDER, "Stasis application support",
    .load_pri = AST_MODPRI_APP_DEPEND - 1,
    .support_level = AST_MODULE_SUPPORT_CORE,
    .load = load_module,
    .unload = unload_module,
);