sessiond: implement ust app clear session

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I9205b25cd18035156485df980104dea5c241542f
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index f3e0209014974f54cf547a91162dcb1c40a246e6..910642f86ed1613c13b2458eb3b8f63498ea57be 100644 (file)
--- a/src/bin/lttng-sessiond/ust-app.c
+++ b/src/bin/lttng-sessiond/ust-app.c
@@ -6547,3 +6547,151 @@ error:
        rcu_read_unlock();
        return ret;
 }
+
+/*
+ * Clear all the channels of a session.
+ *
+ * Return LTTNG_OK on success or else an LTTng error code.
+ */
+enum lttng_error_code ust_app_clear_session(struct ltt_session *session)
+{
+       int ret;
+       enum lttng_error_code cmd_ret = LTTNG_OK;
+       struct lttng_ht_iter iter;
+       struct ust_app *app;
+       struct ltt_ust_session *usess = session->ust_session;
+
+       assert(usess);
+
+       rcu_read_lock();
+
+       if (usess->active) {
+               ERR("Expecting inactive session %s (%" PRIu64 ")", session->name, session->id);
+               cmd_ret = LTTNG_ERR_FATAL;
+               goto end;
+       }
+
+       switch (usess->buffer_type) {
+       case LTTNG_BUFFER_PER_UID:
+       {
+               struct buffer_reg_uid *reg;
+
+               cds_list_for_each_entry(reg, &usess->buffer_reg_uid_list, lnode) {
+                       struct buffer_reg_channel *reg_chan;
+                       struct consumer_socket *socket;
+
+                       /* Get consumer socket to use to push the metadata.*/
+                       socket = consumer_find_socket_by_bitness(reg->bits_per_long,
+                                       usess->consumer);
+                       if (!socket) {
+                               cmd_ret = LTTNG_ERR_INVALID;
+                               goto error_socket;
+                       }
+
+                       /* Clear the data channels. */
+                       cds_lfht_for_each_entry(reg->registry->channels->ht, &iter.iter,
+                                       reg_chan, node.node) {
+                               ret = consumer_clear_channel(socket,
+                                               reg_chan->consumer_key);
+                               if (ret < 0) {
+                                       goto error;
+                               }
+                       }
+
+                       (void) push_metadata(reg->registry->reg.ust, usess->consumer);
+
+                       /*
+                        * Clear the metadata channel.
+                        * Metadata channel is not cleared per se but we still need to
+                        * perform a rotation operation on it behind the scene.
+                        */
+                       ret = consumer_clear_channel(socket,
+                                       reg->registry->reg.ust->metadata_key);
+                       if (ret < 0) {
+                               goto error;
+                       }
+               }
+               break;
+       }
+       case LTTNG_BUFFER_PER_PID:
+       {
+               cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) {
+                       struct consumer_socket *socket;
+                       struct lttng_ht_iter chan_iter;
+                       struct ust_app_channel *ua_chan;
+                       struct ust_app_session *ua_sess;
+                       struct ust_registry_session *registry;
+
+                       ua_sess = lookup_session_by_app(usess, app);
+                       if (!ua_sess) {
+                               /* Session not associated with this app. */
+                               continue;
+                       }
+
+                       /* Get the right consumer socket for the application. */
+                       socket = consumer_find_socket_by_bitness(app->bits_per_long,
+                                       usess->consumer);
+                       if (!socket) {
+                               cmd_ret = LTTNG_ERR_INVALID;
+                               goto error_socket;
+                       }
+
+                       registry = get_session_registry(ua_sess);
+                       if (!registry) {
+                               DBG("Application session is being torn down. Skip application.");
+                               continue;
+                       }
+
+                       /* Clear the data channels. */
+                       cds_lfht_for_each_entry(ua_sess->channels->ht, &chan_iter.iter,
+                                       ua_chan, node.node) {
+                               ret = consumer_clear_channel(socket, ua_chan->key);
+                               if (ret < 0) {
+                                       /* Per-PID buffer and application going away. */
+                                       if (ret == -LTTNG_ERR_CHAN_NOT_FOUND) {
+                                               continue;
+                                       }
+                                       goto error;
+                               }
+                       }
+
+                       (void) push_metadata(registry, usess->consumer);
+
+                       /*
+                        * Clear the metadata channel.
+                        * Metadata channel is not cleared per se but we still need to
+                        * perform rotation operation on it behind the scene.
+                        */
+                       ret = consumer_clear_channel(socket, registry->metadata_key);
+                       if (ret < 0) {
+                               /* Per-PID buffer and application going away. */
+                               if (ret == -LTTNG_ERR_CHAN_NOT_FOUND) {
+                                       continue;
+                               }
+                               goto error;
+                       }
+               }
+               break;
+       }
+       default:
+               assert(0);
+               break;
+       }
+
+       cmd_ret = LTTNG_OK;
+       goto end;
+
+error:
+       switch (-ret) {
+       case LTTCOMM_CONSUMERD_RELAYD_CLEAR_DISALLOWED:
+               cmd_ret = LTTNG_ERR_CLEAR_RELAY_DISALLOWED;
+               break;
+       default:
+               cmd_ret = LTTNG_ERR_CLEAR_FAIL_CONSUMER;
+       }
+
+error_socket:
+end:
+       rcu_read_unlock();
+       return cmd_ret;
+}

diff --git a/src/bin/lttng-sessiond/ust-app.h b/src/bin/lttng-sessiond/ust-app.h
index 86f747d6b6714b3d8b7230cea290ad89ac3c30a3..25aeada6541359505041199a97135e6ab66590d6 100644 (file)
--- a/src/bin/lttng-sessiond/ust-app.h
+++ b/src/bin/lttng-sessiond/ust-app.h
@@ -365,6 +365,7 @@ enum lttng_error_code ust_app_create_channel_subdirectories(
                const struct ltt_ust_session *session);
 int ust_app_release_object(struct ust_app *app,
                struct lttng_ust_object_data *data);
+enum lttng_error_code ust_app_clear_session(struct ltt_session *session);
 
 static inline
 int ust_app_supported(void)
@@ -611,6 +612,12 @@ int ust_app_release_object(struct ust_app *app, struct lttng_ust_object_data *da
        return 0;
 }
 
+static inline
+enum lttng_error_code ust_app_clear_session(struct ltt_session *session)
+{
+       return 0;
+}
+
 #endif /* HAVE_LIBLTTNG_UST_CTL */
 
 #endif /* _LTT_UST_APP_H */