res_pjsip_mwi: use an ao2_global object for mwi containers

On shutdown it's possible for the unsolicited mwi container to be freed before
other dependent threads are done using it. This patch ensures this can no
longer happen by wrapping the container in an ao2_global object. The solicited
container was also changed too.

ASTERISK-28552

Change-Id: I8f812286dc19a34916acacd71ce2ec26e1042047

diff --git a/res/res_pjsip_mwi.c b/res/res_pjsip_mwi.c
index 49b5dc56c42ccb02cab054bcb5504031e09d3ea4..d7749fab6468ce3b6cea751212abb4b1e180ddcc 100644 (file)
--- a/res/res_pjsip_mwi.c
+++ b/res/res_pjsip_mwi.c
@@ -42,8 +42,9 @@
 #include "asterisk/mwi.h"
 
 struct mwi_subscription;
-static struct ao2_container *unsolicited_mwi;
-static struct ao2_container *solicited_mwi;
+
+AO2_GLOBAL_OBJ_STATIC(mwi_unsolicited);
+AO2_GLOBAL_OBJ_STATIC(mwi_solicited);
 
 static char *default_voicemail_extension;
 
@@ -581,13 +582,15 @@ static int unsubscribe_stasis(void *obj, void *arg, int flags)
 }
 
 static int create_unsolicited_mwi_subscriptions(struct ast_sip_endpoint *endpoint,
-               int recreate, int send_now);
+       int recreate, int send_now, struct ao2_container *unsolicited_mwi, struct ao2_container *solicited_mwi);
 
 static void mwi_subscription_shutdown(struct ast_sip_subscription *sub)
 {
        struct mwi_subscription *mwi_sub;
        struct ast_datastore *mwi_datastore;
        struct ast_sip_endpoint *endpoint = NULL;
+       struct ao2_container *unsolicited_mwi;
+       struct ao2_container *solicited_mwi;
 
        mwi_datastore = ast_sip_subscription_get_datastore(sub, MWI_DATASTORE);
        if (!mwi_datastore) {
@@ -601,18 +604,25 @@ static void mwi_subscription_shutdown(struct ast_sip_subscription *sub)
        endpoint = ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "endpoint", mwi_sub->id);
 
        ao2_ref(mwi_datastore, -1);
-       ao2_unlink(solicited_mwi, mwi_sub);
+
+       solicited_mwi = ao2_global_obj_ref(mwi_solicited);
+       if (solicited_mwi) {
+               ao2_unlink(solicited_mwi, mwi_sub);
+       }
 
        /*
         * When a solicited subscription is removed it's possible an unsolicited one
         * needs to be [re-]created. Attempt to establish unsolicited MWI.
         */
+       unsolicited_mwi = ao2_global_obj_ref(mwi_unsolicited);
        if (unsolicited_mwi && endpoint) {
                ao2_lock(unsolicited_mwi);
-               create_unsolicited_mwi_subscriptions(endpoint, 1, 1);
+               create_unsolicited_mwi_subscriptions(endpoint, 1, 1, unsolicited_mwi, solicited_mwi);
                ao2_unlock(unsolicited_mwi);
+               ao2_ref(unsolicited_mwi, -1);
        }
 
+       ao2_cleanup(solicited_mwi);
        ao2_cleanup(endpoint);
 }
 
@@ -678,6 +688,10 @@ static int has_mwi_subscription(struct ao2_container *container,
        *mwi_sub = NULL;
        *mwi_stasis = NULL;
 
+       if (!container) {
+               return 0;
+       }
+
        mwi_subs = ao2_find(container, ast_sorcery_object_get_id(endpoint),
                                                OBJ_SEARCH_KEY | OBJ_MULTIPLE | OBJ_NOLOCK);
        if (!mwi_subs) {
@@ -707,11 +721,13 @@ static int has_mwi_subscription(struct ao2_container *container,
  *
  * \param endpoint The endpoint
  * \param mailbox The mailbox
+ * \param unsolicited_mwi A container of unsolicited mwi objects
  *
  * \retval 1 if a solicited subscription is allowed for the endpoint/mailbox
  *         0 otherwise
  */
-static int allow_and_or_replace_unsolicited(struct ast_sip_endpoint *endpoint, const char *mailbox)
+static int allow_and_or_replace_unsolicited(struct ast_sip_endpoint *endpoint, const char *mailbox,
+       struct ao2_container *unsolicited_mwi)
 {
        struct mwi_subscription *mwi_sub;
        struct mwi_stasis_subscription *mwi_stasis;
@@ -758,11 +774,14 @@ static int send_notify(void *obj, void *arg, int flags);
  *
  * \param endpoint The endpoint
  * \param mailbox The mailbox
+ * \param unsolicited_mwi A container of unsolicited mwi objects
+ * \param solicited_mwi A container of solicited mwi objects
  *
  * \retval 1 if an unsolicited subscription is allowed for the endpoint/mailbox
  *         0 otherwise
  */
-static int is_unsolicited_allowed(struct ast_sip_endpoint *endpoint, const char *mailbox)
+static int is_unsolicited_allowed(struct ast_sip_endpoint *endpoint, const char *mailbox,
+       struct ao2_container *unsolicited_mwi, struct ao2_container *solicited_mwi)
 {
        struct mwi_subscription *mwi_sub;
        struct mwi_stasis_subscription *mwi_stasis;
@@ -828,28 +847,41 @@ static int mwi_validate_for_aor(void *obj, void *arg, int flags)
        struct ast_sip_endpoint *endpoint = arg;
        char *mailboxes;
        char *mailbox;
+       struct ao2_container *unsolicited_mwi;
 
        if (ast_strlen_zero(aor->mailboxes)) {
                return 0;
        }
 
        /* A reload could be taking place so lock while checking if allowed */
-       ao2_lock(unsolicited_mwi);
+       unsolicited_mwi = ao2_global_obj_ref(mwi_unsolicited);
+       if (unsolicited_mwi) {
+               ao2_lock(unsolicited_mwi);
+       }
+
        mailboxes = ast_strdupa(aor->mailboxes);
        while ((mailbox = ast_strip(strsep(&mailboxes, ",")))) {
                if (ast_strlen_zero(mailbox)) {
                        continue;
                }
 
-               if (!allow_and_or_replace_unsolicited(endpoint, mailbox)) {
+               if (!allow_and_or_replace_unsolicited(endpoint, mailbox, unsolicited_mwi)) {
                        ast_debug(1, "Endpoint '%s' already configured for unsolicited MWI for mailbox '%s'. "
                                        "Denying MWI subscription to %s\n", ast_sorcery_object_get_id(endpoint), mailbox,
                                        ast_sorcery_object_get_id(aor));
-                       ao2_unlock(unsolicited_mwi);
+
+                       if (unsolicited_mwi) {
+                               ao2_unlock(unsolicited_mwi);
+                               ao2_ref(unsolicited_mwi, -1);
+                       }
                        return -1;
                }
        }
-       ao2_unlock(unsolicited_mwi);
+
+       if (unsolicited_mwi) {
+               ao2_unlock(unsolicited_mwi);
+               ao2_ref(unsolicited_mwi, -1);
+       }
 
        return 0;
 }
@@ -975,6 +1007,7 @@ static int mwi_subscription_established(struct ast_sip_subscription *sip_sub)
        const char *resource = ast_sip_subscription_get_resource_name(sip_sub);
        struct mwi_subscription *sub;
        struct ast_sip_endpoint *endpoint = ast_sip_subscription_get_endpoint(sip_sub);
+       struct ao2_container *solicited_mwi;
 
        /* no aor in uri? subscribe to all on endpoint */
        if (ast_strlen_zero(resource)) {
@@ -995,7 +1028,12 @@ static int mwi_subscription_established(struct ast_sip_subscription *sip_sub)
                ast_sip_subscription_remove_datastore(sip_sub, MWI_DATASTORE);
        }
 
-       ao2_link(solicited_mwi, sub);
+       solicited_mwi = ao2_global_obj_ref(mwi_solicited);
+       if (solicited_mwi) {
+               ao2_link(solicited_mwi, sub);
+               ao2_ref(solicited_mwi, -1);
+       }
+
        ao2_cleanup(sub);
        ao2_cleanup(endpoint);
        return 0;
@@ -1142,11 +1180,13 @@ static void mwi_stasis_cb(void *userdata, struct stasis_subscription *sub,
  * \param endpoint An endpoint object
  * \param recreate Whether or not unsolicited subscriptions are potentially being recreated
  * \param send_now Whether or not to send a notify once the subscription is created
+ * \param unsolicited_mwi A container of unsolicited mwi objects
+ * \param solicited_mwi A container of solicited mwi objects
  *
  * \retval 0
  */
 static int create_unsolicited_mwi_subscriptions(struct ast_sip_endpoint *endpoint,
-               int recreate, int send_now)
+       int recreate, int send_now, struct ao2_container *unsolicited_mwi, struct ao2_container *solicited_mwi)
 {
        RAII_VAR(struct mwi_subscription *, aggregate_sub, NULL, ao2_cleanup);
        char *mailboxes;
@@ -1181,14 +1221,16 @@ static int create_unsolicited_mwi_subscriptions(struct ast_sip_endpoint *endpoin
        }
 
        /* Lock solicited so we don't potentially add to both containers */
-       ao2_lock(solicited_mwi);
+       if (solicited_mwi) {
+               ao2_lock(solicited_mwi);
+       }
 
        mailboxes = ast_strdupa(endpoint->subscription.mwi.mailboxes);
        while ((mailbox = ast_strip(strsep(&mailboxes, ",")))) {
                struct mwi_subscription *sub;
                struct mwi_stasis_subscription *mwi_stasis_sub;
 
-               if (!is_unsolicited_allowed(endpoint, mailbox)) {
+               if (!is_unsolicited_allowed(endpoint, mailbox, unsolicited_mwi, solicited_mwi)) {
                        continue;
                }
 
@@ -1228,13 +1270,16 @@ static int create_unsolicited_mwi_subscriptions(struct ast_sip_endpoint *endpoin
                }
        }
 
-       ao2_unlock(solicited_mwi);
+       if (solicited_mwi) {
+               ao2_unlock(solicited_mwi);
+       }
+
        return 0;
 }
 
-static int create_mwi_subscriptions_for_endpoint(void *obj, void *arg, int flags)
+static int create_mwi_subscriptions_for_endpoint(void *obj, void *arg, void *data, int flags)
 {
-       return create_unsolicited_mwi_subscriptions(obj, 0, 0);
+       return create_unsolicited_mwi_subscriptions(obj, 0, 0, arg, data);
 }
 
 static int unsubscribe(void *obj, void *arg, int flags)
@@ -1248,9 +1293,16 @@ static int unsubscribe(void *obj, void *arg, int flags)
 
 static void create_mwi_subscriptions(void)
 {
+       struct ao2_container *unsolicited_mwi;
+       struct ao2_container *solicited_mwi;
        struct ao2_container *endpoints;
        struct ast_variable *var;
 
+       unsolicited_mwi = ao2_global_obj_ref(mwi_unsolicited);
+       if (!unsolicited_mwi) {
+               return;
+       }
+
        var = ast_variable_new("mailboxes !=", "", "");
 
        endpoints = ast_sorcery_retrieve_by_fields(ast_sip_get_sorcery(), "endpoint",
@@ -1258,9 +1310,12 @@ static void create_mwi_subscriptions(void)
 
        ast_variables_destroy(var);
        if (!endpoints) {
+               ao2_ref(unsolicited_mwi, -1);
                return;
        }
 
+       solicited_mwi = ao2_global_obj_ref(mwi_solicited);
+
        /* We remove all the old stasis subscriptions first before applying the new configuration. This
         * prevents a situation where there might be multiple overlapping stasis subscriptions for an
         * endpoint for mailboxes. Though there may be mailbox changes during the gap between unsubscribing
@@ -1269,10 +1324,12 @@ static void create_mwi_subscriptions(void)
         */
        ao2_lock(unsolicited_mwi);
        ao2_callback(unsolicited_mwi, OBJ_NOLOCK | OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, unsubscribe, NULL);
-       ao2_callback(endpoints, OBJ_NODATA, create_mwi_subscriptions_for_endpoint, NULL);
+       ao2_callback_data(endpoints, OBJ_NODATA, create_mwi_subscriptions_for_endpoint, unsolicited_mwi, solicited_mwi);
        ao2_unlock(unsolicited_mwi);
 
        ao2_ref(endpoints, -1);
+       ao2_cleanup(solicited_mwi);
+       ao2_ref(unsolicited_mwi, -1);
 }
 
 /*! \brief Function called to send MWI NOTIFY on any unsolicited mailboxes relating to this AOR */
@@ -1299,6 +1356,8 @@ static void mwi_contact_changed(const struct ast_sip_contact *contact)
        char *id = ast_strdupa(ast_sorcery_object_get_id(contact));
        char *aor = NULL;
        struct ast_sip_endpoint *endpoint = NULL;
+       struct ao2_container *unsolicited_mwi;
+       struct ao2_container *solicited_mwi;
 
        if (contact->endpoint) {
                endpoint = ao2_bump(contact->endpoint);
@@ -1313,10 +1372,20 @@ static void mwi_contact_changed(const struct ast_sip_contact *contact)
                return;
        }
 
+       unsolicited_mwi = ao2_global_obj_ref(mwi_unsolicited);
+       if (!unsolicited_mwi) {
+               ao2_cleanup(endpoint);
+               return;
+       }
+
+       solicited_mwi = ao2_global_obj_ref(mwi_solicited);
+
        ao2_lock(unsolicited_mwi);
-       create_mwi_subscriptions_for_endpoint(endpoint, NULL, 0);
+       create_unsolicited_mwi_subscriptions(endpoint, 0, 0, unsolicited_mwi, solicited_mwi);
        ao2_unlock(unsolicited_mwi);
        ao2_cleanup(endpoint);
+       ao2_cleanup(solicited_mwi);
+       ao2_ref(unsolicited_mwi, -1);
 
        aor = strsep(&id, ";@");
        ao2_callback(unsolicited_mwi, OBJ_NODATA, send_contact_notify, aor);
@@ -1342,6 +1411,7 @@ static void mwi_contact_deleted(const void *object)
        struct mwi_subscription *mwi_sub;
        struct ast_sip_endpoint *endpoint = NULL;
        struct ast_sip_contact *found_contact;
+       struct ao2_container *unsolicited_mwi;
 
        if (contact->endpoint) {
                endpoint = ao2_bump(contact->endpoint);
@@ -1364,6 +1434,11 @@ static void mwi_contact_deleted(const void *object)
                return;
        }
 
+       unsolicited_mwi = ao2_global_obj_ref(mwi_unsolicited);
+       if (!unsolicited_mwi) {
+               return;
+       }
+
        ao2_lock(unsolicited_mwi);
        mwi_subs = ao2_find(unsolicited_mwi, contact->endpoint_name,
                OBJ_SEARCH_KEY | OBJ_MULTIPLE | OBJ_NOLOCK | OBJ_UNLINK);
@@ -1374,6 +1449,7 @@ static void mwi_contact_deleted(const void *object)
                ao2_iterator_destroy(mwi_subs);
        }
        ao2_unlock(unsolicited_mwi);
+       ao2_ref(unsolicited_mwi, -1);
 }
 
 /*! \brief Observer for contacts so unsolicited MWI is sent when a contact changes */
@@ -1386,7 +1462,12 @@ static const struct ast_sorcery_observer mwi_contact_observer = {
 /*! \brief Task invoked to send initial MWI NOTIFY for unsolicited */
 static int send_initial_notify_all(void *obj)
 {
-       ao2_callback(unsolicited_mwi, OBJ_NODATA, send_notify, NULL);
+       struct ao2_container *unsolicited_mwi = ao2_global_obj_ref(mwi_unsolicited);
+
+       if (unsolicited_mwi) {
+               ao2_callback(unsolicited_mwi, OBJ_NODATA, send_notify, NULL);
+               ao2_ref(unsolicited_mwi, -1);
+       }
 
        return 0;
 }
@@ -1434,8 +1515,38 @@ static int reload(void)
        return 0;
 }
 
+static int unload_module(void)
+{
+       struct ao2_container *unsolicited_mwi;
+
+       ast_sorcery_observer_remove(ast_sip_get_sorcery(), "global", &global_observer);
+       ast_sorcery_observer_remove(ast_sip_get_sorcery(), "contact", &mwi_contact_observer);
+
+       unsolicited_mwi = ao2_global_obj_replace(mwi_unsolicited, NULL);
+       if (unsolicited_mwi) {
+               ao2_callback(unsolicited_mwi, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, unsubscribe, NULL);
+               ao2_ref(unsolicited_mwi, -1);
+       }
+
+       ao2_global_obj_release(mwi_solicited);
+
+       if (ast_serializer_pool_destroy(mwi_serializer_pool)) {
+               ast_log(LOG_WARNING, "Unload incomplete. Try again later\n");
+               return -1;
+       }
+       mwi_serializer_pool = NULL;
+
+       ast_sip_unregister_subscription_handler(&mwi_handler);
+
+       ast_free(default_voicemail_extension);
+       default_voicemail_extension = NULL;
+       return 0;
+}
+
 static int load_module(void)
 {
+       struct ao2_container *mwi_container;
+
        if (ast_sip_register_subscription_handler(&mwi_handler)) {
                return AST_MODULE_LOAD_DECLINE;
        }
@@ -1446,22 +1557,23 @@ static int load_module(void)
                ast_log(AST_LOG_WARNING, "Failed to create MWI serializer pool. The default SIP pool will be used for MWI\n");
        }
 
-       solicited_mwi = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0, MWI_BUCKETS,
+       mwi_container = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0, MWI_BUCKETS,
                mwi_sub_hash, NULL, mwi_sub_cmp);
-       if (!solicited_mwi) {
-               ast_serializer_pool_destroy(mwi_serializer_pool);
-               ast_sip_unregister_subscription_handler(&mwi_handler);
+       if (!mwi_container) {
+               unload_module();
                return AST_MODULE_LOAD_DECLINE;
        }
+       ao2_global_obj_replace_unref(mwi_solicited, mwi_container);
+       ao2_ref(mwi_container, -1);
 
-       unsolicited_mwi = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0, MWI_BUCKETS,
+       mwi_container = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0, MWI_BUCKETS,
                mwi_sub_hash, NULL, mwi_sub_cmp);
-       if (!unsolicited_mwi) {
-               ast_serializer_pool_destroy(mwi_serializer_pool);
-               ast_sip_unregister_subscription_handler(&mwi_handler);
-               ao2_ref(solicited_mwi, -1);
+       if (!mwi_container) {
+               unload_module();
                return AST_MODULE_LOAD_DECLINE;
        }
+       ao2_global_obj_replace_unref(mwi_unsolicited, mwi_container);
+       ao2_ref(mwi_container, -1);
 
        ast_sorcery_observer_add(ast_sip_get_sorcery(), "contact", &mwi_contact_observer);
        ast_sorcery_observer_add(ast_sip_get_sorcery(), "global", &global_observer);
@@ -1493,35 +1605,6 @@ static int load_module(void)
        return AST_MODULE_LOAD_SUCCESS;
 }
 
-static int unload_module(void)
-{
-       ast_sorcery_observer_remove(ast_sip_get_sorcery(), "global", &global_observer);
-       ast_sorcery_observer_remove(ast_sip_get_sorcery(), "contact", &mwi_contact_observer);
-
-       if (unsolicited_mwi) {
-               ao2_callback(unsolicited_mwi, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, unsubscribe, NULL);
-               ao2_ref(unsolicited_mwi, -1);
-               unsolicited_mwi = NULL;
-       }
-
-       if (solicited_mwi) {
-               ao2_ref(solicited_mwi, -1);
-               solicited_mwi = NULL;
-       }
-
-       if (ast_serializer_pool_destroy(mwi_serializer_pool)) {
-               ast_log(LOG_WARNING, "Unload incomplete. Try again later\n");
-               return -1;
-       }
-       mwi_serializer_pool = NULL;
-
-       ast_sip_unregister_subscription_handler(&mwi_handler);
-
-       ast_free(default_voicemail_extension);
-       default_voicemail_extension = NULL;
-       return 0;
-}
-
 AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP MWI resource",
        .support_level = AST_MODULE_SUPPORT_CORE,
        .load = load_module,