Fix: sessiond: notification: unreachable code in switch-case
[lttng-tools.git] / src / bin / lttng-sessiond / notification-thread-events.c
index 81fba4e6912253c7daf8b825594bf3106cc93361..833b550f87067672a682ccc99bcec710361c90be 100644 (file)
@@ -125,6 +125,19 @@ struct lttng_condition_list_element {
        struct cds_list_head node;
 };
 
+/*
+ * Facilities to carry the different notifications type in the action processing
+ * code path.
+ */
+struct lttng_event_notifier_notification {
+       union {
+               struct lttng_ust_event_notifier_notification *ust;
+               struct lttng_kernel_event_notifier_notification *kernel;
+       } notification;
+       uint64_t token;
+       enum lttng_domain_type type;
+};
+
 struct channel_state_sample {
        struct channel_key key;
        struct cds_lfht_node channel_state_ht_node;
@@ -318,6 +331,38 @@ 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.
@@ -1921,7 +1966,6 @@ int handle_notification_thread_command_add_tracer_event_source(
                goto end;
        }
 
-       CDS_INIT_LIST_HEAD(&element->node);
        element->fd = tracer_event_source_fd;
        element->domain = domain_type;
 
@@ -1956,6 +2000,7 @@ int handle_notification_thread_command_remove_tracer_event_source(
                enum lttng_error_code *_cmd_result)
 {
        int ret = 0;
+       bool found = false;
        enum lttng_error_code cmd_result = LTTNG_OK;
        struct notification_event_tracer_event_source_element *source_element = NULL, *tmp;
 
@@ -1969,11 +2014,19 @@ int handle_notification_thread_command_remove_tracer_event_source(
                                tracer_event_source_fd,
                                lttng_domain_type_str(source_element->domain));
                cds_list_del(&source_element->node);
+               found = true;
                break;
        }
 
-       /* It should always be found. */
-       assert(source_element);
+       if (!found) {
+               /*
+                * This is temporarily allowed since the poll activity set is
+                * not properly cleaned-up for the moment. This is adressed in
+                * an upcoming fix.
+                */
+               source_element = NULL;
+               goto end;
+       }
 
        if (!source_element->is_fd_in_poll_set) {
                /* Skip the poll set removal. */
@@ -1994,6 +2047,8 @@ int handle_notification_thread_command_remove_tracer_event_source(
                goto end;
        }
 
+       source_element->is_fd_in_poll_set = false;
+
 end:
        free(source_element);
        *_cmd_result = cmd_result;
@@ -2555,11 +2610,15 @@ 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;
@@ -2575,9 +2634,6 @@ 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) {
@@ -2660,7 +2716,7 @@ 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;
@@ -2668,7 +2724,7 @@ 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;
 
@@ -2779,21 +2835,22 @@ 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,
@@ -2806,7 +2863,6 @@ 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,
@@ -2814,9 +2870,6 @@ 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,
@@ -2855,7 +2908,6 @@ 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;
@@ -4122,6 +4174,99 @@ end:
        return ret;
 }
 
+int handle_notification_thread_event_notification(struct notification_thread_state *state,
+               int notification_pipe_read_fd,
+               enum lttng_domain_type domain)
+{
+       int ret;
+       struct lttng_ust_event_notifier_notification ust_notification;
+       struct lttng_kernel_event_notifier_notification kernel_notification;
+       struct cds_lfht_node *node;
+       struct cds_lfht_iter iter;
+       struct notification_trigger_tokens_ht_element *element;
+       enum lttng_action_type action_type;
+       const struct lttng_action *action;
+       struct lttng_event_notifier_notification notification;
+       void *reception_buffer;
+       size_t reception_size;
+
+       notification.type = domain;
+
+       switch(domain) {
+       case LTTNG_DOMAIN_UST:
+               reception_buffer = (void *) &ust_notification;
+               reception_size = sizeof(ust_notification);
+               notification.notification.ust = &ust_notification;
+               break;
+       case LTTNG_DOMAIN_KERNEL:
+               reception_buffer = (void *) &kernel_notification;
+               reception_size = sizeof(kernel_notification);
+               notification.notification.kernel = &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:
+               notification.token = ust_notification.token;
+               break;
+       case LTTNG_DOMAIN_KERNEL:
+               notification.token = kernel_notification.token;
+               break;
+       default:
+               abort();
+       }
+
+       /* Find triggers associated with this token. */
+       rcu_read_lock();
+       cds_lfht_lookup(state->trigger_tokens_ht,
+                       hash_key_u64(&notification.token, lttng_ht_seed),
+                       match_trigger_token, &notification.token, &iter);
+       node = cds_lfht_iter_get_node(&iter);
+       if (caa_likely(!node)) {
+               /*
+                * This is not an error, slow consumption of the pipe can lead
+                * to situations where a trigger is removed but we still get
+                * tracer notification matching to a previous trigger.
+                */
+               ret = 0;
+               goto end_unlock;
+       }
+
+       element = caa_container_of(node,
+                       struct notification_trigger_tokens_ht_element,
+                       node);
+
+       action = lttng_trigger_get_const_action(element->trigger);
+       action_type = lttng_action_get_type(action);
+       DBG("Received message from tracer event source: event source fd = %d, token = %" PRIu64 ", action type = '%s'",
+                       notification_pipe_read_fd, notification.token,
+                       lttng_action_type_string(action_type));
+
+       /* TODO: Perform actions */
+
+       ret = 0;
+
+end_unlock:
+       rcu_read_unlock();
+end:
+       return ret;
+}
+
 int handle_notification_thread_channel_sample(
                struct notification_thread_state *state, int pipe,
                enum lttng_domain_type domain)
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