Implements `lttng_event_notifier_notification_{create,destroy}()`
[lttng-tools.git] / src / bin / lttng-sessiond / notification-thread-events.c
index 212746faa1c7a50d67e3006f868908222a00d22c..823f2a7eb3b2d53a4642844738ebd808445e2f26 100644 (file)
@@ -318,6 +318,38 @@ int match_session(struct cds_lfht_node *node, const void *key)
        return !strcmp(session_info->name, name);
 }
 
+static
+const char *notification_command_type_str(
+               enum notification_thread_command_type type)
+{
+       switch (type) {
+       case NOTIFICATION_COMMAND_TYPE_REGISTER_TRIGGER:
+               return "REGISTER_TRIGGER";
+       case NOTIFICATION_COMMAND_TYPE_UNREGISTER_TRIGGER:
+               return "UNREGISTER_TRIGGER";
+       case NOTIFICATION_COMMAND_TYPE_ADD_CHANNEL:
+               return "ADD_CHANNEL";
+       case NOTIFICATION_COMMAND_TYPE_REMOVE_CHANNEL:
+               return "REMOVE_CHANNEL";
+       case NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING:
+               return "SESSION_ROTATION_ONGOING";
+       case NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_COMPLETED:
+               return "SESSION_ROTATION_COMPLETED";
+       case NOTIFICATION_COMMAND_TYPE_ADD_TRACER_EVENT_SOURCE:
+               return "ADD_TRACER_EVENT_SOURCE";
+       case NOTIFICATION_COMMAND_TYPE_REMOVE_TRACER_EVENT_SOURCE:
+               return "REMOVE_TRACER_EVENT_SOURCE";
+       case NOTIFICATION_COMMAND_TYPE_LIST_TRIGGERS:
+               return "LIST_TRIGGERS";
+       case NOTIFICATION_COMMAND_TYPE_QUIT:
+               return "QUIT";
+       case NOTIFICATION_COMMAND_TYPE_CLIENT_COMMUNICATION_UPDATE:
+               return "CLIENT_COMMUNICATION_UPDATE";
+       default:
+               abort();
+       }
+}
+
 /*
  * Match trigger based on name and credentials only.
  * Name duplication is NOT allowed for the same uid.
@@ -1609,7 +1641,7 @@ int handle_notification_thread_command_add_channel(
 
        DBG("[notification-thread] Adding channel %s from session %s, channel key = %" PRIu64 " in %s domain",
                        channel_name, session_name, channel_key_int,
-                       channel_domain == LTTNG_DOMAIN_KERNEL ? "kernel" : "user space");
+                       lttng_domain_type_str(channel_domain));
 
        CDS_INIT_LIST_HEAD(&trigger_list);
 
@@ -1710,7 +1742,7 @@ int handle_notification_thread_command_remove_channel(
        struct channel_info *channel_info;
 
        DBG("[notification-thread] Removing channel key = %" PRIu64 " in %s domain",
-                       channel_key, domain == LTTNG_DOMAIN_KERNEL ? "kernel" : "user space");
+                       channel_key, lttng_domain_type_str(domain));
 
        rcu_read_lock();
 
@@ -2565,11 +2597,15 @@ int handle_notification_thread_command_register_trigger(
                ret = evaluate_session_condition_for_client(condition, state,
                                &evaluation, &object_uid,
                                &object_gid);
+               LTTNG_OPTIONAL_SET(&object_creds.uid, object_uid);
+               LTTNG_OPTIONAL_SET(&object_creds.gid, object_gid);
                break;
        case LTTNG_OBJECT_TYPE_CHANNEL:
                ret = evaluate_channel_condition_for_client(condition, state,
                                &evaluation, &object_uid,
                                &object_gid);
+               LTTNG_OPTIONAL_SET(&object_creds.uid, object_uid);
+               LTTNG_OPTIONAL_SET(&object_creds.gid, object_gid);
                break;
        case LTTNG_OBJECT_TYPE_NONE:
                ret = 0;
@@ -2585,9 +2621,6 @@ int handle_notification_thread_command_register_trigger(
                goto error_put_client_list;
        }
 
-       LTTNG_OPTIONAL_SET(&object_creds.uid, object_uid);
-       LTTNG_OPTIONAL_SET(&object_creds.gid, object_gid);
-
        DBG("Newly registered trigger's condition evaluated to %s",
                        evaluation ? "true" : "false");
        if (!evaluation) {
@@ -2670,7 +2703,7 @@ void free_notification_trigger_tokens_ht_element_rcu(struct rcu_head *node)
 static
 int handle_notification_thread_command_unregister_trigger(
                struct notification_thread_state *state,
-               struct lttng_trigger *trigger,
+               const struct lttng_trigger *trigger,
                enum lttng_error_code *_cmd_reply)
 {
        struct cds_lfht_iter iter;
@@ -2678,7 +2711,7 @@ int handle_notification_thread_command_unregister_trigger(
        struct lttng_channel_trigger_list *trigger_list;
        struct notification_client_list *client_list;
        struct lttng_trigger_ht_element *trigger_ht_element = NULL;
-       struct lttng_condition *condition = lttng_trigger_get_condition(
+       const struct lttng_condition *condition = lttng_trigger_get_const_condition(
                        trigger);
        enum lttng_error_code cmd_reply;
 
@@ -2789,21 +2822,22 @@ int handle_notification_thread_command(
                        struct notification_thread_command, cmd_list_node);
        cds_list_del(&cmd->cmd_list_node);
        pthread_mutex_unlock(&handle->cmd_queue.lock);
+
+       DBG("[notification-thread] Received `%s` command",
+                       notification_command_type_str(cmd->type));
        switch (cmd->type) {
        case NOTIFICATION_COMMAND_TYPE_REGISTER_TRIGGER:
-               DBG("[notification-thread] Received register trigger command");
-               ret = handle_notification_thread_command_register_trigger(
-                               state, cmd->parameters.trigger,
+               ret = handle_notification_thread_command_register_trigger(state,
+                               cmd->parameters.register_trigger.trigger,
                                &cmd->reply_code);
                break;
        case NOTIFICATION_COMMAND_TYPE_UNREGISTER_TRIGGER:
-               DBG("[notification-thread] Received unregister trigger command");
                ret = handle_notification_thread_command_unregister_trigger(
-                               state, cmd->parameters.trigger,
+                               state,
+                               cmd->parameters.unregister_trigger.trigger,
                                &cmd->reply_code);
                break;
        case NOTIFICATION_COMMAND_TYPE_ADD_CHANNEL:
-               DBG("[notification-thread] Received add channel command");
                ret = handle_notification_thread_command_add_channel(
                                state,
                                cmd->parameters.add_channel.session.name,
@@ -2816,7 +2850,6 @@ int handle_notification_thread_command(
                                &cmd->reply_code);
                break;
        case NOTIFICATION_COMMAND_TYPE_REMOVE_CHANNEL:
-               DBG("[notification-thread] Received remove channel command");
                ret = handle_notification_thread_command_remove_channel(
                                state, cmd->parameters.remove_channel.key,
                                cmd->parameters.remove_channel.domain,
@@ -2824,9 +2857,6 @@ int handle_notification_thread_command(
                break;
        case NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING:
        case NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_COMPLETED:
-               DBG("[notification-thread] Received session rotation %s command",
-                               cmd->type == NOTIFICATION_COMMAND_TYPE_SESSION_ROTATION_ONGOING ?
-                               "ongoing" : "completed");
                ret = handle_notification_thread_command_session_rotation(
                                state,
                                cmd->type,
@@ -2865,7 +2895,6 @@ int handle_notification_thread_command(
                break;
        }
        case NOTIFICATION_COMMAND_TYPE_QUIT:
-               DBG("[notification-thread] Received quit command");
                cmd->reply_code = LTTNG_OK;
                ret = 1;
                goto end;
@@ -4132,6 +4161,199 @@ end:
        return ret;
 }
 
+static struct lttng_event_notifier_notification *receive_notification(
+               int notification_pipe_read_fd, enum lttng_domain_type domain)
+{
+       int ret;
+       uint64_t token;
+       struct lttng_event_notifier_notification *notification = NULL;
+       void *reception_buffer;
+       size_t reception_size;
+
+       struct lttng_ust_event_notifier_notification ust_notification;
+       struct lttng_kernel_event_notifier_notification kernel_notification;
+
+       /* Init lttng_event_notifier_notification */
+       switch(domain) {
+       case LTTNG_DOMAIN_UST:
+               reception_buffer = (void *) &ust_notification;
+               reception_size = sizeof(ust_notification);
+               break;
+       case LTTNG_DOMAIN_KERNEL:
+               reception_buffer = (void *) &kernel_notification;
+               reception_size = sizeof(kernel_notification);
+               break;
+       default:
+               abort();
+       }
+
+       /*
+        * The monitoring pipe only holds messages smaller than PIPE_BUF,
+        * ensuring that read/write of tracer notifications are atomic.
+        */
+       ret = lttng_read(notification_pipe_read_fd, reception_buffer,
+                       reception_size);
+       if (ret != reception_size) {
+               PERROR("Failed to read from event source notification pipe: fd = %d, size to read = %zu, ret = %d",
+                               notification_pipe_read_fd, reception_size, ret);
+               ret = -1;
+               goto end;
+       }
+
+       switch(domain) {
+       case LTTNG_DOMAIN_UST:
+               token = ust_notification.token;
+               break;
+       case LTTNG_DOMAIN_KERNEL:
+               token = kernel_notification.token;
+               break;
+       default:
+               abort();
+       }
+
+       notification = lttng_event_notifier_notification_create(
+                       token, domain);
+end:
+       return notification;
+}
+
+int handle_notification_thread_event_notification(struct notification_thread_state *state,
+               int pipe,
+               enum lttng_domain_type domain)
+{
+       int ret;
+       enum lttng_trigger_status trigger_status;
+       struct cds_lfht_node *node;
+       struct cds_lfht_iter iter;
+       struct notification_trigger_tokens_ht_element *element;
+       struct lttng_evaluation *evaluation = NULL;
+       struct lttng_event_notifier_notification *notification = NULL;
+       enum action_executor_status executor_status;
+       struct notification_client_list *client_list = NULL;
+       const char *trigger_name;
+
+       notification = receive_notification(pipe, domain);
+       if (notification == NULL) {
+               ERR("[notification-thread] Error receiving notification from tracer (fd = %i, domain = %s)",
+                               pipe, lttng_domain_type_str(domain));
+               ret = -1;
+               goto end;
+       }
+
+       /* Find triggers associated with this token. */
+       rcu_read_lock();
+       cds_lfht_lookup(state->trigger_tokens_ht,
+                       hash_key_u64(&notification->tracer_token, lttng_ht_seed),
+                       match_trigger_token, &notification->tracer_token, &iter);
+       node = cds_lfht_iter_get_node(&iter);
+       if (caa_unlikely(!node)) {
+               /*
+                * This is not an error, slow consumption of the tracer
+                * notifications can lead to situations where a trigger is
+                * removed but we still get tracer notifications matching a
+                * trigger that no longer exists.
+                */
+               ret = 0;
+               goto end_unlock;
+       }
+
+       element = caa_container_of(node,
+                       struct notification_trigger_tokens_ht_element,
+                       node);
+
+       if (!lttng_trigger_should_fire(element->trigger)) {
+               ret = 0;
+               goto end_unlock;
+       }
+
+       lttng_trigger_fire(element->trigger);
+
+       trigger_status = lttng_trigger_get_name(element->trigger, &trigger_name);
+       assert(trigger_status == LTTNG_TRIGGER_STATUS_OK);
+
+       evaluation = lttng_evaluation_event_rule_create(
+                       trigger_name);
+       if (evaluation == NULL) {
+               ERR("[notification-thread] Failed to create event rule hit evaluation while creating and enqueuing action executor job");
+               ret = -1;
+               goto end_unlock;
+       }
+
+       client_list = get_client_list_from_condition(state,
+                       lttng_trigger_get_const_condition(element->trigger));
+       executor_status = action_executor_enqueue(state->executor,
+                       element->trigger, evaluation, NULL, client_list);
+       switch (executor_status) {
+       case ACTION_EXECUTOR_STATUS_OK:
+               ret = 0;
+               break;
+       case ACTION_EXECUTOR_STATUS_OVERFLOW:
+       {
+               struct notification_client_list_element *client_list_element,
+                               *tmp;
+
+               /*
+                * Not a fatal error; this is expected and simply means the
+                * executor has too much work queued already.
+                */
+               ret = 0;
+
+               /* No clients subscribed to notifications for this trigger. */
+               if (!client_list) {
+                       break;
+               }
+
+               /* Warn clients that a notification (or more) was dropped. */
+               pthread_mutex_lock(&client_list->lock);
+               cds_list_for_each_entry_safe(client_list_element, tmp,
+                               &client_list->list, node) {
+                       enum client_transmission_status transmission_status;
+                       struct notification_client *client =
+                                       client_list_element->client;
+
+                       pthread_mutex_lock(&client->lock);
+                       ret = client_notification_overflow(client);
+                       if (ret) {
+                               /* Fatal error. */
+                               goto next_client;
+                       }
+
+                       transmission_status =
+                                       client_flush_outgoing_queue(client);
+                       ret = client_handle_transmission_status(
+                                       client, transmission_status, state);
+                       if (ret) {
+                               /* Fatal error. */
+                               goto next_client;
+                       }
+next_client:
+                       pthread_mutex_unlock(&client->lock);
+                       if (ret) {
+                               break;
+                       }
+               }
+
+               pthread_mutex_unlock(&client_list->lock);
+               break;
+       }
+       case ACTION_EXECUTOR_STATUS_ERROR:
+               /* Fatal error, shut down everything. */
+               ERR("Fatal error encoutered while enqueuing action to the action executor");
+               ret = -1;
+               goto end_unlock;
+       default:
+               /* Unhandled error. */
+               abort();
+       }
+
+end_unlock:
+       lttng_event_notifier_notification_destroy(notification);
+       notification_client_list_put(client_list);
+       rcu_read_unlock();
+end:
+       return ret;
+}
+
 int handle_notification_thread_channel_sample(
                struct notification_thread_state *state, int pipe,
                enum lttng_domain_type domain)
@@ -4185,8 +4407,7 @@ int handle_notification_thread_channel_sample(
                 */
                DBG("[notification-thread] Received a sample for an unknown channel from consumerd, key = %" PRIu64 " in %s domain",
                                latest_sample.key.key,
-                               domain == LTTNG_DOMAIN_KERNEL ? "kernel" :
-                                       "user space");
+                               lttng_domain_type_str(domain));
                goto end_unlock;
        }
        channel_info = caa_container_of(node, struct channel_info,
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