X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-events.c;h=b024c4cf327603a59c105b9aaf090dc65b48e608;hb=bdb12629ec5577e27573886dfc229552df94a7c2;hp=d9efebe6bae215427d304335b6c564fb6939168b;hpb=fb470188155efff12ac07733111d6e6f5c532cc0;p=lttng-ust.git

diff --git a/liblttng-ust/lttng-events.c b/liblttng-ust/lttng-events.c
index d9efebe6..b024c4cf 100644
--- a/liblttng-ust/lttng-events.c
+++ b/liblttng-ust/lttng-events.c
@@ -1,31 +1,17 @@
 /*
- * lttng-events.c
- *
- * Holds LTTng per-session event registry.
+ * SPDX-License-Identifier: LGPL-2.1-only
  *
  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ * Holds LTTng per-session event registry.
  */
 
 #define _LGPL_SOURCE
 #include <stdio.h>
-#include <urcu/list.h>
-#include <urcu/hlist.h>
-#include <pthread.h>
+#include <assert.h>
 #include <errno.h>
+#include <limits.h>
+#include <pthread.h>
 #include <sys/shm.h>
 #include <sys/ipc.h>
 #include <stdint.h>
@@ -33,36 +19,43 @@
 #include <inttypes.h>
 #include <time.h>
 #include <stdbool.h>
+#include <unistd.h>
+#include <dlfcn.h>
 #include <lttng/ust-endian.h>
-#include "clock.h"
 
-#include <urcu-bp.h>
+#include <urcu/arch.h>
 #include <urcu/compiler.h>
+#include <urcu/hlist.h>
+#include <urcu/list.h>
 #include <urcu/uatomic.h>
-#include <urcu/arch.h>
 
 #include <lttng/tracepoint.h>
 #include <lttng/ust-events.h>
 
 #include <usterr-signal-safe.h>
-#include <helper.h>
+#include <ust-helper.h>
 #include <lttng/ust-ctl.h>
 #include <ust-comm.h>
-#include <lttng/ust-dynamic-type.h>
-#include <lttng/ust-context-provider.h>
+#include <ust-fd.h>
+#include <ust-dynamic-type.h>
+#include <ust-context-provider.h>
 #include "error.h"
 #include "compat.h"
 #include "lttng-ust-uuid.h"
 
 #include "tracepoint-internal.h"
 #include "string-utils.h"
+#include "lttng-bytecode.h"
 #include "lttng-tracer.h"
 #include "lttng-tracer-core.h"
 #include "lttng-ust-statedump.h"
+#include "context-internal.h"
 #include "ust-events-internal.h"
 #include "wait.h"
 #include "../libringbuffer/shm.h"
+#include "../libcounter/counter.h"
 #include "jhash.h"
+#include <lttng/ust-abi.h>
 
 /*
  * All operations within this file are called by the communication
@@ -70,13 +63,16 @@
  */
 
 static CDS_LIST_HEAD(sessions);
+static CDS_LIST_HEAD(event_notifier_groups);
 
-struct cds_list_head *_lttng_get_sessions(void)
+struct cds_list_head *lttng_get_sessions(void)
 {
 	return &sessions;
 }
 
 static void _lttng_event_destroy(struct lttng_event *event);
+static void _lttng_event_notifier_destroy(
+		struct lttng_event_notifier *event_notifier);
 static void _lttng_enum_destroy(struct lttng_enum *_enum);
 
 static
@@ -84,6 +80,9 @@ void lttng_session_lazy_sync_event_enablers(struct lttng_session *session);
 static
 void lttng_session_sync_event_enablers(struct lttng_session *session);
 static
+void lttng_event_notifier_group_sync_enablers(
+		struct lttng_event_notifier_group *event_notifier_group);
+static
 void lttng_enabler_destroy(struct lttng_enabler *enabler);
 
 /*
@@ -91,10 +90,10 @@ void lttng_enabler_destroy(struct lttng_enabler *enabler);
  */
 int lttng_session_active(void)
 {
-	struct lttng_session *iter;
+	struct lttng_ust_session_private *iter;
 
 	cds_list_for_each_entry(iter, &sessions, node) {
-		if (iter->active)
+		if (iter->pub->active)
 			return 1;
 	}
 	return 0;
@@ -130,35 +129,104 @@ int lttng_loglevel_match(int loglevel,
 	}
 }
 
-void synchronize_trace(void)
-{
-	synchronize_rcu();
-}
-
 struct lttng_session *lttng_session_create(void)
 {
 	struct lttng_session *session;
+	struct lttng_ust_session_private *session_priv;
 	int i;
 
 	session = zmalloc(sizeof(struct lttng_session));
 	if (!session)
 		return NULL;
-	if (lttng_session_context_init(&session->ctx)) {
+	session_priv = zmalloc(sizeof(struct lttng_ust_session_private));
+	if (!session_priv) {
+		free(session);
+		return NULL;
+	}
+	session->priv = session_priv;
+	session_priv->pub = session;
+	if (lttng_context_init_all(&session->priv->ctx)) {
+		free(session_priv);
 		free(session);
 		return NULL;
 	}
-	CDS_INIT_LIST_HEAD(&session->chan_head);
-	CDS_INIT_LIST_HEAD(&session->events_head);
-	CDS_INIT_LIST_HEAD(&session->enums_head);
-	CDS_INIT_LIST_HEAD(&session->enablers_head);
+	CDS_INIT_LIST_HEAD(&session->priv->chan_head);
+	CDS_INIT_LIST_HEAD(&session->priv->events_head);
+	CDS_INIT_LIST_HEAD(&session->priv->enums_head);
+	CDS_INIT_LIST_HEAD(&session->priv->enablers_head);
 	for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
-		CDS_INIT_HLIST_HEAD(&session->events_ht.table[i]);
+		CDS_INIT_HLIST_HEAD(&session->priv->events_ht.table[i]);
 	for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
-		CDS_INIT_HLIST_HEAD(&session->enums_ht.table[i]);
-	cds_list_add(&session->node, &sessions);
+		CDS_INIT_HLIST_HEAD(&session->priv->enums_ht.table[i]);
+	cds_list_add(&session->priv->node, &sessions);
 	return session;
 }
 
+struct lttng_counter *lttng_ust_counter_create(
+		const char *counter_transport_name,
+		size_t number_dimensions, const struct lttng_counter_dimension *dimensions)
+{
+	struct lttng_counter_transport *counter_transport = NULL;
+	struct lttng_counter *counter = NULL;
+
+	counter_transport = lttng_counter_transport_find(counter_transport_name);
+	if (!counter_transport)
+		goto notransport;
+	counter = zmalloc(sizeof(struct lttng_counter));
+	if (!counter)
+		goto nomem;
+
+	counter->ops = &counter_transport->ops;
+	counter->transport = counter_transport;
+
+	counter->counter = counter->ops->counter_create(
+			number_dimensions, dimensions, 0,
+			-1, 0, NULL, false);
+	if (!counter->counter) {
+		goto create_error;
+	}
+
+	return counter;
+
+create_error:
+	free(counter);
+nomem:
+notransport:
+	return NULL;
+}
+
+static
+void lttng_ust_counter_destroy(struct lttng_counter *counter)
+{
+	counter->ops->counter_destroy(counter->counter);
+	free(counter);
+}
+
+struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
+{
+	struct lttng_event_notifier_group *event_notifier_group;
+	int i;
+
+	event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
+	if (!event_notifier_group)
+		return NULL;
+
+	/* Add all contexts. */
+	if (lttng_context_init_all(&event_notifier_group->ctx)) {
+		free(event_notifier_group);
+		return NULL;
+	}
+
+	CDS_INIT_LIST_HEAD(&event_notifier_group->enablers_head);
+	CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
+	for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
+		CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
+
+	cds_list_add(&event_notifier_group->node, &event_notifier_groups);
+
+	return event_notifier_group;
+}
+
 /*
  * Only used internally at session destruction.
  */
@@ -185,14 +253,29 @@ void register_event(struct lttng_event *event)
 	int ret;
 	const struct lttng_event_desc *desc;
 
-	assert(event->registered == 0);
-	desc = event->desc;
+	assert(event->priv->registered == 0);
+	desc = event->priv->desc;
 	ret = __tracepoint_probe_register_queue_release(desc->name,
 			desc->probe_callback,
 			event, desc->signature);
 	WARN_ON_ONCE(ret);
 	if (!ret)
-		event->registered = 1;
+		event->priv->registered = 1;
+}
+
+static
+void register_event_notifier(struct lttng_event_notifier *event_notifier)
+{
+	int ret;
+	const struct lttng_event_desc *desc;
+
+	assert(event_notifier->registered == 0);
+	desc = event_notifier->desc;
+	ret = __tracepoint_probe_register_queue_release(desc->name,
+		desc->u.ext.event_notifier_callback, event_notifier, desc->signature);
+	WARN_ON_ONCE(ret);
+	if (!ret)
+		event_notifier->registered = 1;
 }
 
 static
@@ -201,14 +284,29 @@ void unregister_event(struct lttng_event *event)
 	int ret;
 	const struct lttng_event_desc *desc;
 
-	assert(event->registered == 1);
-	desc = event->desc;
+	assert(event->priv->registered == 1);
+	desc = event->priv->desc;
 	ret = __tracepoint_probe_unregister_queue_release(desc->name,
 			desc->probe_callback,
 			event);
 	WARN_ON_ONCE(ret);
 	if (!ret)
-		event->registered = 0;
+		event->priv->registered = 0;
+}
+
+static
+void unregister_event_notifier(struct lttng_event_notifier *event_notifier)
+{
+	int ret;
+	const struct lttng_event_desc *desc;
+
+	assert(event_notifier->registered == 1);
+	desc = event_notifier->desc;
+	ret = __tracepoint_probe_unregister_queue_release(desc->name,
+		desc->u.ext.event_notifier_callback, event_notifier);
+	WARN_ON_ONCE(ret);
+	if (!ret)
+		event_notifier->registered = 0;
 }
 
 /*
@@ -217,43 +315,100 @@ void unregister_event(struct lttng_event *event)
 static
 void _lttng_event_unregister(struct lttng_event *event)
 {
-	if (event->registered)
+	if (event->priv->registered)
 		unregister_event(event);
 }
 
+/*
+ * Only used internally at session destruction.
+ */
+static
+void _lttng_event_notifier_unregister(struct lttng_event_notifier *event_notifier)
+{
+	if (event_notifier->registered)
+		unregister_event_notifier(event_notifier);
+}
+
 void lttng_session_destroy(struct lttng_session *session)
 {
 	struct lttng_channel *chan, *tmpchan;
-	struct lttng_event *event, *tmpevent;
+	struct lttng_ust_event_private *event_priv, *tmpevent_priv;
 	struct lttng_enum *_enum, *tmp_enum;
 	struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 
 	CMM_ACCESS_ONCE(session->active) = 0;
-	cds_list_for_each_entry(event, &session->events_head, node) {
-		_lttng_event_unregister(event);
+	cds_list_for_each_entry(event_priv, &session->priv->events_head, node) {
+		_lttng_event_unregister(event_priv->pub);
 	}
-	synchronize_trace();	/* Wait for in-flight events to complete */
+	lttng_ust_urcu_synchronize_rcu();	/* Wait for in-flight events to complete */
 	__tracepoint_probe_prune_release_queue();
 	cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
-			&session->enablers_head, node)
+			&session->priv->enablers_head, node)
 		lttng_event_enabler_destroy(event_enabler);
-	cds_list_for_each_entry_safe(event, tmpevent,
-			&session->events_head, node)
-		_lttng_event_destroy(event);
+	cds_list_for_each_entry_safe(event_priv, tmpevent_priv,
+			&session->priv->events_head, node)
+		_lttng_event_destroy(event_priv->pub);
 	cds_list_for_each_entry_safe(_enum, tmp_enum,
-			&session->enums_head, node)
+			&session->priv->enums_head, node)
 		_lttng_enum_destroy(_enum);
-	cds_list_for_each_entry_safe(chan, tmpchan, &session->chan_head, node)
+	cds_list_for_each_entry_safe(chan, tmpchan, &session->priv->chan_head, node)
 		_lttng_channel_unmap(chan);
-	cds_list_del(&session->node);
-	lttng_destroy_context(session->ctx);
+	cds_list_del(&session->priv->node);
+	lttng_destroy_context(session->priv->ctx);
+	free(session->priv);
 	free(session);
 }
 
+void lttng_event_notifier_group_destroy(
+		struct lttng_event_notifier_group *event_notifier_group)
+{
+	int close_ret;
+	struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
+	struct lttng_event_notifier *notifier, *tmpnotifier;
+
+	if (!event_notifier_group) {
+		return;
+	}
+
+	cds_list_for_each_entry(notifier,
+			&event_notifier_group->event_notifiers_head, node)
+		_lttng_event_notifier_unregister(notifier);
+
+	lttng_ust_urcu_synchronize_rcu();
+
+	cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
+			&event_notifier_group->enablers_head, node)
+		lttng_event_notifier_enabler_destroy(notifier_enabler);
+
+	cds_list_for_each_entry_safe(notifier, tmpnotifier,
+			&event_notifier_group->event_notifiers_head, node)
+		_lttng_event_notifier_destroy(notifier);
+
+	if (event_notifier_group->error_counter)
+		lttng_ust_counter_destroy(event_notifier_group->error_counter);
+
+	/* Close the notification fd to the listener of event_notifiers. */
+
+	lttng_ust_lock_fd_tracker();
+	close_ret = close(event_notifier_group->notification_fd);
+	if (!close_ret) {
+		lttng_ust_delete_fd_from_tracker(
+				event_notifier_group->notification_fd);
+	} else {
+		PERROR("close");
+		abort();
+	}
+	lttng_ust_unlock_fd_tracker();
+
+	cds_list_del(&event_notifier_group->node);
+
+	free(event_notifier_group);
+}
+
 static
 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 {
-	struct lttng_ust_filter_bytecode_node *filter_node, *tmp_filter_node;
+	struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 	struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 
 	if (!enabler) {
@@ -273,6 +428,19 @@ void lttng_enabler_destroy(struct lttng_enabler *enabler)
 	}
 }
 
+ void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
+{
+	if (!event_notifier_enabler) {
+		return;
+	}
+
+	cds_list_del(&event_notifier_enabler->node);
+
+	lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
+
+	free(event_notifier_enabler);
+}
+
 static
 int lttng_enum_create(const struct lttng_enum_desc *desc,
 		struct lttng_session *session)
@@ -287,7 +455,7 @@ int lttng_enum_create(const struct lttng_enum_desc *desc,
 
 	/* Check if this enum is already registered for this session. */
 	hash = jhash(enum_name, name_len, 0);
-	head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
+	head = &session->priv->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 
 	_enum = lttng_ust_enum_get_from_desc(session, desc);
 	if (_enum) {
@@ -295,7 +463,7 @@ int lttng_enum_create(const struct lttng_enum_desc *desc,
 		goto exist;
 	}
 
-	notify_socket = lttng_get_notify_socket(session->owner);
+	notify_socket = lttng_get_notify_socket(session->priv->owner);
 	if (notify_socket < 0) {
 		ret = notify_socket;
 		goto socket_error;
@@ -310,7 +478,7 @@ int lttng_enum_create(const struct lttng_enum_desc *desc,
 	_enum->desc = desc;
 
 	ret = ustcomm_register_enum(notify_socket,
-		session->objd,
+		session->priv->objd,
 		enum_name,
 		desc->nr_entries,
 		desc->entries,
@@ -319,7 +487,7 @@ int lttng_enum_create(const struct lttng_enum_desc *desc,
 		DBG("Error (%d) registering enumeration to sessiond", ret);
 		goto sessiond_register_error;
 	}
-	cds_list_add(&_enum->node, &session->enums_head);
+	cds_list_add(&_enum->node, &session->priv->enums_head);
 	cds_hlist_add_head(&_enum->hlist, head);
 	return 0;
 
@@ -428,8 +596,8 @@ int lttng_create_all_ctx_enums(size_t nr_fields,
  */
 int lttng_session_statedump(struct lttng_session *session)
 {
-	session->statedump_pending = 1;
-	lttng_ust_sockinfo_session_enabled(session->owner);
+	session->priv->statedump_pending = 1;
+	lttng_ust_sockinfo_session_enabled(session->priv->owner);
 	return 0;
 }
 
@@ -444,12 +612,12 @@ int lttng_session_enable(struct lttng_session *session)
 		goto end;
 	}
 
-	notify_socket = lttng_get_notify_socket(session->owner);
+	notify_socket = lttng_get_notify_socket(session->priv->owner);
 	if (notify_socket < 0)
 		return notify_socket;
 
 	/* Set transient enabler state to "enabled" */
-	session->tstate = 1;
+	session->priv->tstate = 1;
 
 	/* We need to sync enablers with session before activation. */
 	lttng_session_sync_event_enablers(session);
@@ -458,7 +626,7 @@ int lttng_session_enable(struct lttng_session *session)
 	 * Snapshot the number of events per channel to know the type of header
 	 * we need to use.
 	 */
-	cds_list_for_each_entry(chan, &session->chan_head, node) {
+	cds_list_for_each_entry(chan, &session->priv->chan_head, node) {
 		const struct lttng_ctx *ctx;
 		const struct lttng_ctx_field *fields = NULL;
 		size_t nr_fields = 0;
@@ -480,7 +648,7 @@ int lttng_session_enable(struct lttng_session *session)
 		}
 		ret = ustcomm_register_channel(notify_socket,
 			session,
-			session->objd,
+			session->priv->objd,
 			chan->objd,
 			nr_fields,
 			fields,
@@ -499,7 +667,7 @@ int lttng_session_enable(struct lttng_session *session)
 
 	/* Set atomically the state to "active" */
 	CMM_ACCESS_ONCE(session->active) = 1;
-	CMM_ACCESS_ONCE(session->been_active) = 1;
+	CMM_ACCESS_ONCE(session->priv->been_active) = 1;
 
 	ret = lttng_session_statedump(session);
 	if (ret)
@@ -520,7 +688,7 @@ int lttng_session_disable(struct lttng_session *session)
 	CMM_ACCESS_ONCE(session->active) = 0;
 
 	/* Set transient enabler state to "disabled" */
-	session->tstate = 0;
+	session->priv->tstate = 0;
 	lttng_session_sync_event_enablers(session);
 end:
 	return ret;
@@ -585,16 +753,17 @@ int lttng_event_create(const struct lttng_event_desc *desc,
 		struct lttng_channel *chan)
 {
 	struct lttng_event *event;
+	struct lttng_ust_event_private *event_priv;
 	struct lttng_session *session = chan->session;
 	struct cds_hlist_head *head;
 	int ret = 0;
 	int notify_socket, loglevel;
 	const char *uri;
 
-	head = borrow_hash_table_bucket(chan->session->events_ht.table,
+	head = borrow_hash_table_bucket(chan->session->priv->events_ht.table,
 		LTTNG_UST_EVENT_HT_SIZE, desc);
 
-	notify_socket = lttng_get_notify_socket(session->owner);
+	notify_socket = lttng_get_notify_socket(session->priv->owner);
 	if (notify_socket < 0) {
 		ret = notify_socket;
 		goto socket_error;
@@ -615,17 +784,24 @@ int lttng_event_create(const struct lttng_event_desc *desc,
 		ret = -ENOMEM;
 		goto cache_error;
 	}
+	event_priv = zmalloc(sizeof(struct lttng_ust_event_private));
+	if (!event_priv) {
+		ret = -ENOMEM;
+		goto priv_error;
+	}
+	event->priv = event_priv;
+	event_priv->pub = event;
 	event->chan = chan;
 
 	/* Event will be enabled by enabler sync. */
 	event->enabled = 0;
-	event->registered = 0;
-	CDS_INIT_LIST_HEAD(&event->bytecode_runtime_head);
-	CDS_INIT_LIST_HEAD(&event->enablers_ref_head);
-	event->desc = desc;
+	event->priv->registered = 0;
+	CDS_INIT_LIST_HEAD(&event->filter_bytecode_runtime_head);
+	CDS_INIT_LIST_HEAD(&event->priv->enablers_ref_head);
+	event->priv->desc = desc;
 
 	if (desc->loglevel)
-		loglevel = *(*event->desc->loglevel);
+		loglevel = *(*event->priv->desc->loglevel);
 	else
 		loglevel = TRACE_DEFAULT;
 	if (desc->u.ext.model_emf_uri)
@@ -636,7 +812,7 @@ int lttng_event_create(const struct lttng_event_desc *desc,
 	/* Fetch event ID from sessiond */
 	ret = ustcomm_register_event(notify_socket,
 		session,
-		session->objd,
+		session->priv->objd,
 		chan->objd,
 		desc->name,
 		loglevel,
@@ -650,11 +826,13 @@ int lttng_event_create(const struct lttng_event_desc *desc,
 		goto sessiond_register_error;
 	}
 
-	cds_list_add(&event->node, &chan->session->events_head);
-	cds_hlist_add_head(&event->hlist, head);
+	cds_list_add(&event->priv->node, &chan->session->priv->events_head);
+	cds_hlist_add_head(&event->priv->hlist, head);
 	return 0;
 
 sessiond_register_error:
+	free(event_priv);
+priv_error:
 	free(event);
 cache_error:
 create_enum_error:
@@ -662,6 +840,72 @@ socket_error:
 	return ret;
 }
 
+static
+int lttng_event_notifier_create(const struct lttng_event_desc *desc,
+		uint64_t token, uint64_t error_counter_index,
+		struct lttng_event_notifier_group *event_notifier_group)
+{
+	struct lttng_event_notifier *event_notifier;
+	struct cds_hlist_head *head;
+	int ret = 0;
+
+	/*
+	 * Get the hashtable bucket the created lttng_event_notifier object
+	 * should be inserted.
+	 */
+	head = borrow_hash_table_bucket(
+		event_notifier_group->event_notifiers_ht.table,
+		LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
+
+	event_notifier = zmalloc(sizeof(struct lttng_event_notifier));
+	if (!event_notifier) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	event_notifier->group = event_notifier_group;
+	event_notifier->user_token = token;
+	event_notifier->error_counter_index = error_counter_index;
+
+	/* Event notifier will be enabled by enabler sync. */
+	event_notifier->enabled = 0;
+	event_notifier->registered = 0;
+
+	CDS_INIT_LIST_HEAD(&event_notifier->filter_bytecode_runtime_head);
+	CDS_INIT_LIST_HEAD(&event_notifier->capture_bytecode_runtime_head);
+	CDS_INIT_LIST_HEAD(&event_notifier->enablers_ref_head);
+	event_notifier->desc = desc;
+	event_notifier->notification_send = lttng_event_notifier_notification_send;
+
+	cds_list_add(&event_notifier->node,
+			&event_notifier_group->event_notifiers_head);
+	cds_hlist_add_head(&event_notifier->hlist, head);
+
+	return 0;
+
+error:
+	return ret;
+}
+
+static
+void _lttng_event_notifier_destroy(struct lttng_event_notifier *event_notifier)
+{
+	struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
+
+	/* Remove from event_notifier list. */
+	cds_list_del(&event_notifier->node);
+	/* Remove from event_notifier hash table. */
+	cds_hlist_del(&event_notifier->hlist);
+
+	lttng_free_event_notifier_filter_runtime(event_notifier);
+
+	/* Free event_notifier enabler refs */
+	cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
+			&event_notifier->enablers_ref_head, node)
+		free(enabler_ref);
+	free(event_notifier);
+}
+
 static
 int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 		struct lttng_enabler *enabler)
@@ -751,7 +995,7 @@ static
 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 		struct lttng_event *event)
 {
-	if (lttng_desc_match_enabler(event->desc,
+	if (lttng_desc_match_enabler(event->priv->desc,
 			lttng_event_enabler_as_enabler(event_enabler))
 			&& event->chan == event_enabler->chan)
 		return 1;
@@ -759,6 +1003,21 @@ int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 		return 0;
 }
 
+static
+int lttng_event_notifier_enabler_match_event_notifier(
+		struct lttng_event_notifier_enabler *event_notifier_enabler,
+		struct lttng_event_notifier *event_notifier)
+{
+	int desc_matches = lttng_desc_match_enabler(event_notifier->desc,
+		lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
+
+	if (desc_matches && event_notifier->group == event_notifier_enabler->group &&
+			event_notifier->user_token == event_notifier_enabler->user_token)
+		return 1;
+	else
+		return 0;
+}
+
 static
 struct lttng_enabler_ref *lttng_enabler_ref(
 		struct cds_list_head *enabler_ref_list,
@@ -783,7 +1042,7 @@ void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
 	struct lttng_session *session = event_enabler->chan->session;
 	struct lttng_probe_desc *probe_desc;
 	const struct lttng_event_desc *desc;
-	struct lttng_event *event;
+	struct lttng_ust_event_private *event_priv;
 	int i;
 	struct cds_list_head *probe_list;
 
@@ -806,12 +1065,12 @@ void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
 				continue;
 
 			head = borrow_hash_table_bucket(
-				session->events_ht.table,
+				session->priv->events_ht.table,
 				LTTNG_UST_EVENT_HT_SIZE, desc);
 
-			cds_hlist_for_each_entry(event, node, head, hlist) {
-				if (event->desc == desc
-						&& event->chan == event_enabler->chan) {
+			cds_hlist_for_each_entry(event_priv, node, head, hlist) {
+				if (event_priv->desc == desc
+						&& event_priv->pub->chan == event_enabler->chan) {
 					found = true;
 					break;
 				}
@@ -833,103 +1092,71 @@ void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
 	}
 }
 
-/*
- * Iterate over all the UST sessions to unregister and destroy all probes from
- * the probe provider descriptor received as argument. Must me called with the
- * ust_lock held.
- */
-void lttng_probe_provider_unregister_events(struct lttng_probe_desc *provider_desc)
+static
+void probe_provider_event_for_each(struct lttng_probe_desc *provider_desc,
+		void (*event_func)(struct lttng_session *session,
+			struct lttng_event *event),
+		void (*event_notifier_func)(struct lttng_event_notifier *event_notifier))
 {
 	struct cds_hlist_node *node, *tmp_node;
 	struct cds_list_head *sessionsp;
-	struct lttng_session *session;
-	struct cds_hlist_head *head;
-	struct lttng_event *event;
-	unsigned int i, j;
+	unsigned int i;
 
 	/* Get handle on list of sessions. */
-	sessionsp = _lttng_get_sessions();
+	sessionsp = lttng_get_sessions();
 
 	/*
-	 * Iterate over all events in the probe provider descriptions and sessions
-	 * to queue the unregistration of the events.
+	 * Iterate over all events in the probe provider descriptions and
+	 * sessions to queue the unregistration of the events.
 	 */
 	for (i = 0; i < provider_desc->nr_events; i++) {
 		const struct lttng_event_desc *event_desc;
+		struct lttng_event_notifier_group *event_notifier_group;
+		struct lttng_event_notifier *event_notifier;
+		struct lttng_ust_session_private *session_priv;
+		struct cds_hlist_head *head;
+		struct lttng_ust_event_private *event_priv;
 
 		event_desc = provider_desc->event_desc[i];
 
-		/* Iterate over all session to find the current event description. */
-		cds_list_for_each_entry(session, sessionsp, node) {
+		/*
+		 * Iterate over all session to find the current event
+		 * description.
+		 */
+		cds_list_for_each_entry(session_priv, sessionsp, node) {
 			/*
-			 * Get the list of events in the hashtable bucket and iterate to
-			 * find the event matching this descriptor.
+			 * Get the list of events in the hashtable bucket and
+			 * iterate to find the event matching this descriptor.
 			 */
 			head = borrow_hash_table_bucket(
-				session->events_ht.table,
+				session_priv->events_ht.table,
 				LTTNG_UST_EVENT_HT_SIZE, event_desc);
 
-			cds_hlist_for_each_entry(event, node, head, hlist) {
-				if (event_desc == event->desc) {
-					/* Queue the unregistration of this event. */
-					_lttng_event_unregister(event);
+			cds_hlist_for_each_entry_safe(event_priv, node, tmp_node, head, hlist) {
+				if (event_desc == event_priv->desc) {
+					event_func(session_priv->pub, event_priv->pub);
 					break;
 				}
 			}
 		}
-	}
 
-	/* Wait for grace period. */
-	synchronize_trace();
-	/* Prune the unregistration queue. */
-	__tracepoint_probe_prune_release_queue();
-
-	/*
-	 * It is now safe to destroy the events and remove them from the event list
-	 * and hashtables.
-	 */
-	for (i = 0; i < provider_desc->nr_events; i++) {
-		const struct lttng_event_desc *event_desc;
-
-		event_desc = provider_desc->event_desc[i];
-
-		/* Iterate over all sessions to find the current event description. */
-		cds_list_for_each_entry(session, sessionsp, node) {
+		/*
+		 * Iterate over all event_notifier groups to find the current event
+		 * description.
+		 */
+		cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
 			/*
-			 * Get the list of events in the hashtable bucket and iterate to
-			 * find the event matching this descriptor.
+			 * Get the list of event_notifiers in the hashtable bucket and
+			 * iterate to find the event_notifier matching this
+			 * descriptor.
 			 */
 			head = borrow_hash_table_bucket(
-				session->events_ht.table,
-				LTTNG_UST_EVENT_HT_SIZE, event_desc);
+				event_notifier_group->event_notifiers_ht.table,
+				LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
 
-			cds_hlist_for_each_entry_safe(event, node, tmp_node, head, hlist) {
-				if (event_desc == event->desc) {
-					/* Destroy enums of the current event. */
-					for (j = 0; j < event->desc->nr_fields; j++) {
-						const struct lttng_enum_desc *enum_desc;
-						const struct lttng_event_field *field;
-						struct lttng_enum *curr_enum;
-
-						field = &(event->desc->fields[j]);
-						switch (field->type.atype) {
-						case atype_enum:
-							enum_desc = field->type.u.legacy.basic.enumeration.desc;
-							break;
-						case atype_enum_nestable:
-							enum_desc = field->type.u.enum_nestable.desc;
-							break;
-						default:
-							continue;
-						}
-						curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
-						if (curr_enum) {
-							_lttng_enum_destroy(curr_enum);
-						}
-					}
-
-					/* Destroy event. */
-					_lttng_event_destroy(event);
+			cds_hlist_for_each_entry_safe(event_notifier, node, tmp_node, head, hlist) {
+				if (event_desc == event_notifier->desc) {
+					event_notifier_func(event_notifier);
 					break;
 				}
 			}
@@ -937,15 +1164,84 @@ void lttng_probe_provider_unregister_events(struct lttng_probe_desc *provider_de
 	}
 }
 
+static
+void _unregister_event(struct lttng_session *session,
+		struct lttng_event *event)
+{
+	_lttng_event_unregister(event);
+}
+
+static
+void _event_enum_destroy(struct lttng_session *session,
+		struct lttng_event *event)
+{
+	unsigned int i;
+
+	/* Destroy enums of the current event. */
+	for (i = 0; i < event->priv->desc->nr_fields; i++) {
+		const struct lttng_enum_desc *enum_desc;
+		const struct lttng_event_field *field;
+		struct lttng_enum *curr_enum;
+
+		field = &(event->priv->desc->fields[i]);
+		switch (field->type.atype) {
+		case atype_enum:
+			enum_desc = field->type.u.legacy.basic.enumeration.desc;
+			break;
+		case atype_enum_nestable:
+			enum_desc = field->type.u.enum_nestable.desc;
+			break;
+		default:
+			continue;
+		}
+
+		curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
+		if (curr_enum) {
+			_lttng_enum_destroy(curr_enum);
+		}
+	}
+
+	/* Destroy event. */
+	_lttng_event_destroy(event);
+}
+
 /*
- * Create events associated with an enabler (if not already present),
+ * Iterate over all the UST sessions to unregister and destroy all probes from
+ * the probe provider descriptor received as argument. Must me called with the
+ * ust_lock held.
+ */
+void lttng_probe_provider_unregister_events(
+		struct lttng_probe_desc *provider_desc)
+{
+	/*
+	 * Iterate over all events in the probe provider descriptions and sessions
+	 * to queue the unregistration of the events.
+	 */
+	probe_provider_event_for_each(provider_desc, _unregister_event,
+		_lttng_event_notifier_unregister);
+
+	/* Wait for grace period. */
+	lttng_ust_urcu_synchronize_rcu();
+	/* Prune the unregistration queue. */
+	__tracepoint_probe_prune_release_queue();
+
+	/*
+	 * It is now safe to destroy the events and remove them from the event list
+	 * and hashtables.
+	 */
+	probe_provider_event_for_each(provider_desc, _event_enum_destroy,
+		_lttng_event_notifier_destroy);
+}
+
+/*
+ * Create events associated with an event enabler (if not already present),
  * and add backward reference from the event to the enabler.
  */
 static
 int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
 {
 	struct lttng_session *session = event_enabler->chan->session;
-	struct lttng_event *event;
+	struct lttng_ust_event_private *event_priv;
 
 	if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
 		goto end;
@@ -954,13 +1250,13 @@ int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
 	lttng_create_event_if_missing(event_enabler);
 
 	/* For each event matching enabler in session event list. */
-	cds_list_for_each_entry(event, &session->events_head, node) {
+	cds_list_for_each_entry(event_priv, &session->priv->events_head, node) {
 		struct lttng_enabler_ref *enabler_ref;
 
-		if (!lttng_event_enabler_match_event(event_enabler, event))
+		if (!lttng_event_enabler_match_event(event_enabler, event_priv->pub))
 			continue;
 
-		enabler_ref = lttng_enabler_ref(&event->enablers_ref_head,
+		enabler_ref = lttng_enabler_ref(&event_priv->enablers_ref_head,
 			lttng_event_enabler_as_enabler(event_enabler));
 		if (!enabler_ref) {
 			/*
@@ -973,16 +1269,16 @@ int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
 			enabler_ref->ref = lttng_event_enabler_as_enabler(
 				event_enabler);
 			cds_list_add(&enabler_ref->node,
-				&event->enablers_ref_head);
+				&event_priv->enablers_ref_head);
 		}
 
 		/*
 		 * Link filter bytecodes if not linked yet.
 		 */
-		lttng_enabler_link_bytecode(event->desc,
-			&session->ctx,
-			&event->bytecode_runtime_head,
-			lttng_event_enabler_as_enabler(event_enabler));
+		lttng_enabler_link_bytecode(event_priv->desc,
+			&session->priv->ctx,
+			&event_priv->pub->filter_bytecode_runtime_head,
+			&lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
 
 		/* TODO: merge event context. */
 	}
@@ -997,10 +1293,20 @@ end:
  */
 int lttng_fix_pending_events(void)
 {
-	struct lttng_session *session;
+	struct lttng_ust_session_private *session_priv;
 
-	cds_list_for_each_entry(session, &sessions, node) {
-		lttng_session_lazy_sync_event_enablers(session);
+	cds_list_for_each_entry(session_priv, &sessions, node) {
+		lttng_session_lazy_sync_event_enablers(session_priv->pub);
+	}
+	return 0;
+}
+
+int lttng_fix_pending_event_notifiers(void)
+{
+	struct lttng_event_notifier_group *event_notifier_group;
+
+	cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
+		lttng_event_notifier_group_sync_enablers(event_notifier_group);
 	}
 	return 0;
 }
@@ -1012,7 +1318,7 @@ int lttng_fix_pending_events(void)
  */
 void lttng_handle_pending_statedump(void *owner)
 {
-	struct lttng_session *session;
+	struct lttng_ust_session_private *session_priv;
 
 	/* Execute state dump */
 	do_lttng_ust_statedump(owner);
@@ -1021,12 +1327,12 @@ void lttng_handle_pending_statedump(void *owner)
 	if (ust_lock()) {
 		goto end;
 	}
-	cds_list_for_each_entry(session, &sessions, node) {
-		if (session->owner != owner)
+	cds_list_for_each_entry(session_priv, &sessions, node) {
+		if (session_priv->owner != owner)
 			continue;
-		if (!session->statedump_pending)
+		if (!session_priv->statedump_pending)
 			continue;
-		session->statedump_pending = 0;
+		session_priv->statedump_pending = 0;
 	}
 end:
 	ust_unlock();
@@ -1042,16 +1348,17 @@ void _lttng_event_destroy(struct lttng_event *event)
 	struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 
 	/* Remove from event list. */
-	cds_list_del(&event->node);
+	cds_list_del(&event->priv->node);
 	/* Remove from event hash table. */
-	cds_hlist_del(&event->hlist);
+	cds_hlist_del(&event->priv->hlist);
 
 	lttng_destroy_context(event->ctx);
 	lttng_free_event_filter_runtime(event);
 	/* Free event enabler refs */
 	cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
-			&event->enablers_ref_head, node)
+			&event->priv->enablers_ref_head, node)
 		free(enabler_ref);
+	free(event->priv);
 	free(event);
 }
 
@@ -1065,10 +1372,10 @@ void _lttng_enum_destroy(struct lttng_enum *_enum)
 
 void lttng_ust_events_exit(void)
 {
-	struct lttng_session *session, *tmpsession;
+	struct lttng_ust_session_private *session_priv, *tmpsession_priv;
 
-	cds_list_for_each_entry_safe(session, tmpsession, &sessions, node)
-		lttng_session_destroy(session);
+	cds_list_for_each_entry_safe(session_priv, tmpsession_priv, &sessions, node)
+		lttng_session_destroy(session_priv->pub);
 }
 
 /*
@@ -1092,12 +1399,52 @@ struct lttng_event_enabler *lttng_event_enabler_create(
 	event_enabler->chan = chan;
 	/* ctx left NULL */
 	event_enabler->base.enabled = 0;
-	cds_list_add(&event_enabler->node, &event_enabler->chan->session->enablers_head);
+	cds_list_add(&event_enabler->node, &event_enabler->chan->session->priv->enablers_head);
 	lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
 
 	return event_enabler;
 }
 
+struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
+		struct lttng_event_notifier_group *event_notifier_group,
+		enum lttng_enabler_format_type format_type,
+		struct lttng_ust_event_notifier *event_notifier_param)
+{
+	struct lttng_event_notifier_enabler *event_notifier_enabler;
+
+	event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
+	if (!event_notifier_enabler)
+		return NULL;
+	event_notifier_enabler->base.format_type = format_type;
+	CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
+	CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
+	CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
+
+	event_notifier_enabler->user_token = event_notifier_param->event.token;
+	event_notifier_enabler->error_counter_index = event_notifier_param->error_counter_index;
+	event_notifier_enabler->num_captures = 0;
+
+	memcpy(&event_notifier_enabler->base.event_param.name,
+		event_notifier_param->event.name,
+		sizeof(event_notifier_enabler->base.event_param.name));
+	event_notifier_enabler->base.event_param.instrumentation =
+		event_notifier_param->event.instrumentation;
+	event_notifier_enabler->base.event_param.loglevel =
+		event_notifier_param->event.loglevel;
+	event_notifier_enabler->base.event_param.loglevel_type =
+		event_notifier_param->event.loglevel_type;
+
+	event_notifier_enabler->base.enabled = 0;
+	event_notifier_enabler->group = event_notifier_group;
+
+	cds_list_add(&event_notifier_enabler->node,
+			&event_notifier_group->enablers_head);
+
+	lttng_event_notifier_group_sync_enablers(event_notifier_group);
+
+	return event_notifier_enabler;
+}
+
 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
 {
 	lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
@@ -1115,17 +1462,19 @@ int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
 }
 
 static
-void _lttng_enabler_attach_bytecode(struct lttng_enabler *enabler,
-		struct lttng_ust_filter_bytecode_node *bytecode)
+void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
+		struct lttng_ust_bytecode_node **bytecode)
 {
-	bytecode->enabler = enabler;
-	cds_list_add_tail(&bytecode->node, &enabler->filter_bytecode_head);
+	(*bytecode)->enabler = enabler;
+	cds_list_add_tail(&(*bytecode)->node, &enabler->filter_bytecode_head);
+	/* Take ownership of bytecode */
+	*bytecode = NULL;
 }
 
-int lttng_event_enabler_attach_bytecode(struct lttng_event_enabler *event_enabler,
-		struct lttng_ust_filter_bytecode_node *bytecode)
+int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
+		struct lttng_ust_bytecode_node **bytecode)
 {
-	_lttng_enabler_attach_bytecode(
+	_lttng_enabler_attach_filter_bytecode(
 		lttng_event_enabler_as_enabler(event_enabler), bytecode);
 
 	lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
@@ -1134,14 +1483,16 @@ int lttng_event_enabler_attach_bytecode(struct lttng_event_enabler *event_enable
 
 static
 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
-		struct lttng_ust_excluder_node *excluder)
+		struct lttng_ust_excluder_node **excluder)
 {
-	excluder->enabler = enabler;
-	cds_list_add_tail(&excluder->node, &enabler->excluder_head);
+	(*excluder)->enabler = enabler;
+	cds_list_add_tail(&(*excluder)->node, &enabler->excluder_head);
+	/* Take ownership of excluder */
+	*excluder = NULL;
 }
 
 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
-		struct lttng_ust_excluder_node *excluder)
+		struct lttng_ust_excluder_node **excluder)
 {
 	_lttng_enabler_attach_exclusion(
 		lttng_event_enabler_as_enabler(event_enabler), excluder);
@@ -1150,6 +1501,64 @@ int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabl
 	return 0;
 }
 
+int lttng_event_notifier_enabler_enable(
+		struct lttng_event_notifier_enabler *event_notifier_enabler)
+{
+	lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
+	lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
+
+	return 0;
+}
+
+int lttng_event_notifier_enabler_disable(
+		struct lttng_event_notifier_enabler *event_notifier_enabler)
+{
+	lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
+	lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
+
+	return 0;
+}
+
+int lttng_event_notifier_enabler_attach_filter_bytecode(
+		struct lttng_event_notifier_enabler *event_notifier_enabler,
+		struct lttng_ust_bytecode_node **bytecode)
+{
+	_lttng_enabler_attach_filter_bytecode(
+		lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
+		bytecode);
+
+	lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
+	return 0;
+}
+
+int lttng_event_notifier_enabler_attach_capture_bytecode(
+		struct lttng_event_notifier_enabler *event_notifier_enabler,
+		struct lttng_ust_bytecode_node **bytecode)
+{
+	(*bytecode)->enabler = lttng_event_notifier_enabler_as_enabler(
+			event_notifier_enabler);
+	cds_list_add_tail(&(*bytecode)->node,
+			&event_notifier_enabler->capture_bytecode_head);
+	/* Take ownership of bytecode */
+	*bytecode = NULL;
+	event_notifier_enabler->num_captures++;
+
+	lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
+	return 0;
+}
+
+int lttng_event_notifier_enabler_attach_exclusion(
+		struct lttng_event_notifier_enabler *event_notifier_enabler,
+		struct lttng_ust_excluder_node **excluder)
+{
+	_lttng_enabler_attach_exclusion(
+		lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
+		excluder);
+
+	lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
+	return 0;
+}
+
 int lttng_attach_context(struct lttng_ust_context *context_param,
 		union ust_args *uargs,
 		struct lttng_ctx **ctx, struct lttng_session *session)
@@ -1159,7 +1568,7 @@ int lttng_attach_context(struct lttng_ust_context *context_param,
 	 * session because the metadata does not allow expressing this
 	 * information outside of the original channel scope.
 	 */
-	if (session->been_active)
+	if (session->priv->been_active)
 		return -EPERM;
 
 	switch (context_param->ctx) {
@@ -1249,23 +1658,23 @@ static
 void lttng_session_sync_event_enablers(struct lttng_session *session)
 {
 	struct lttng_event_enabler *event_enabler;
-	struct lttng_event *event;
+	struct lttng_ust_event_private *event_priv;
 
-	cds_list_for_each_entry(event_enabler, &session->enablers_head, node)
+	cds_list_for_each_entry(event_enabler, &session->priv->enablers_head, node)
 		lttng_event_enabler_ref_events(event_enabler);
 	/*
 	 * For each event, if at least one of its enablers is enabled,
 	 * and its channel and session transient states are enabled, we
 	 * enable the event, else we disable it.
 	 */
-	cds_list_for_each_entry(event, &session->events_head, node) {
+	cds_list_for_each_entry(event_priv, &session->priv->events_head, node) {
 		struct lttng_enabler_ref *enabler_ref;
 		struct lttng_bytecode_runtime *runtime;
 		int enabled = 0, has_enablers_without_bytecode = 0;
 
 		/* Enable events */
 		cds_list_for_each_entry(enabler_ref,
-				&event->enablers_ref_head, node) {
+				&event_priv->enablers_ref_head, node) {
 			if (enabler_ref->ref->enabled) {
 				enabled = 1;
 				break;
@@ -1276,37 +1685,255 @@ void lttng_session_sync_event_enablers(struct lttng_session *session)
 		 * intesection of session and channel transient enable
 		 * states.
 		 */
-		enabled = enabled && session->tstate && event->chan->tstate;
+		enabled = enabled && session->priv->tstate && event_priv->pub->chan->tstate;
 
-		CMM_STORE_SHARED(event->enabled, enabled);
+		CMM_STORE_SHARED(event_priv->pub->enabled, enabled);
 		/*
 		 * Sync tracepoint registration with event enabled
 		 * state.
 		 */
 		if (enabled) {
-			if (!event->registered)
-				register_event(event);
+			if (!event_priv->registered)
+				register_event(event_priv->pub);
+		} else {
+			if (event_priv->registered)
+				unregister_event(event_priv->pub);
+		}
+
+		/* Check if has enablers without bytecode enabled */
+		cds_list_for_each_entry(enabler_ref,
+				&event_priv->enablers_ref_head, node) {
+			if (enabler_ref->ref->enabled
+					&& cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
+				has_enablers_without_bytecode = 1;
+				break;
+			}
+		}
+		event_priv->pub->has_enablers_without_bytecode =
+			has_enablers_without_bytecode;
+
+		/* Enable filters */
+		cds_list_for_each_entry(runtime,
+				&event_priv->pub->filter_bytecode_runtime_head, node) {
+			lttng_bytecode_filter_sync_state(runtime);
+		}
+	}
+	__tracepoint_probe_prune_release_queue();
+}
+
+/* Support for event notifier is introduced by probe provider major version 2. */
+static
+bool lttng_ust_probe_supports_event_notifier(struct lttng_probe_desc *probe_desc)
+{
+	return probe_desc->major >= 2;
+}
+
+static
+void lttng_create_event_notifier_if_missing(
+		struct lttng_event_notifier_enabler *event_notifier_enabler)
+{
+	struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
+	struct lttng_probe_desc *probe_desc;
+	struct cds_list_head *probe_list;
+	int i;
+
+	probe_list = lttng_get_probe_list_head();
+
+	cds_list_for_each_entry(probe_desc, probe_list, head) {
+		for (i = 0; i < probe_desc->nr_events; i++) {
+			int ret;
+			bool found = false;
+			const struct lttng_event_desc *desc;
+			struct lttng_event_notifier *event_notifier;
+			struct cds_hlist_head *head;
+			struct cds_hlist_node *node;
+
+			desc = probe_desc->event_desc[i];
+
+			if (!lttng_desc_match_enabler(desc,
+					lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
+				continue;
+
+			/*
+			 * Given the current event_notifier group, get the bucket that
+			 * the target event_notifier would be if it was already
+			 * created.
+			 */
+			head = borrow_hash_table_bucket(
+				event_notifier_group->event_notifiers_ht.table,
+				LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
+
+			cds_hlist_for_each_entry(event_notifier, node, head, hlist) {
+				/*
+				 * Check if event_notifier already exists by checking
+				 * if the event_notifier and enabler share the same
+				 * description and id.
+				 */
+				if (event_notifier->desc == desc &&
+						event_notifier->user_token == event_notifier_enabler->user_token) {
+					found = true;
+					break;
+				}
+			}
+
+			if (found)
+				continue;
+
+			/* Check that the probe supports event notifiers, else report the error. */
+			if (!lttng_ust_probe_supports_event_notifier(probe_desc)) {
+				ERR("Probe \"%s\" contains event \"%s\" which matches an enabled event notifier, "
+					"but its version (%u.%u) is too old and does not implement event notifiers. "
+					"It needs to be recompiled against a newer version of LTTng-UST, otherwise "
+					"this event will not generate any notification.",
+					probe_desc->provider,
+					desc->name,
+					probe_desc->major,
+					probe_desc->minor);
+				continue;
+			}
+			/*
+			 * We need to create a event_notifier for this event probe.
+			 */
+			ret = lttng_event_notifier_create(desc,
+				event_notifier_enabler->user_token,
+				event_notifier_enabler->error_counter_index,
+				event_notifier_group);
+			if (ret) {
+				DBG("Unable to create event_notifier %s, error %d\n",
+					probe_desc->event_desc[i]->name, ret);
+			}
+		}
+	}
+}
+
+/*
+ * Create event_notifiers associated with a event_notifier enabler (if not already present).
+ */
+static
+int lttng_event_notifier_enabler_ref_event_notifiers(
+		struct lttng_event_notifier_enabler *event_notifier_enabler)
+{
+	struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
+	struct lttng_event_notifier *event_notifier;
+
+	 /*
+	  * Only try to create event_notifiers for enablers that are enabled, the user
+	  * might still be attaching filter or exclusion to the
+	  * event_notifier_enabler.
+	  */
+	if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
+		goto end;
+
+	/* First, ensure that probe event_notifiers are created for this enabler. */
+	lttng_create_event_notifier_if_missing(event_notifier_enabler);
+
+	/* Link the created event_notifier with its associated enabler. */
+	cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
+		struct lttng_enabler_ref *enabler_ref;
+
+		if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier))
+			continue;
+
+		enabler_ref = lttng_enabler_ref(&event_notifier->enablers_ref_head,
+			lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
+		if (!enabler_ref) {
+			/*
+			 * If no backward ref, create it.
+			 * Add backward ref from event_notifier to enabler.
+			 */
+			enabler_ref = zmalloc(sizeof(*enabler_ref));
+			if (!enabler_ref)
+				return -ENOMEM;
+
+			enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
+				event_notifier_enabler);
+			cds_list_add(&enabler_ref->node,
+				&event_notifier->enablers_ref_head);
+		}
+
+		/*
+		 * Link filter bytecodes if not linked yet.
+		 */
+		lttng_enabler_link_bytecode(event_notifier->desc,
+			&event_notifier_group->ctx,
+			&event_notifier->filter_bytecode_runtime_head,
+			&lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
+
+		/*
+		 * Link capture bytecodes if not linked yet.
+		 */
+		lttng_enabler_link_bytecode(event_notifier->desc,
+			&event_notifier_group->ctx, &event_notifier->capture_bytecode_runtime_head,
+			&event_notifier_enabler->capture_bytecode_head);
+
+		event_notifier->num_captures = event_notifier_enabler->num_captures;
+	}
+end:
+	return 0;
+}
+
+static
+void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
+{
+	struct lttng_event_notifier_enabler *event_notifier_enabler;
+	struct lttng_event_notifier *event_notifier;
+
+	cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
+		lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
+
+	/*
+	 * For each event_notifier, if at least one of its enablers is enabled,
+	 * we enable the event_notifier, else we disable it.
+	 */
+	cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
+		struct lttng_enabler_ref *enabler_ref;
+		struct lttng_bytecode_runtime *runtime;
+		int enabled = 0, has_enablers_without_bytecode = 0;
+
+		/* Enable event_notifiers */
+		cds_list_for_each_entry(enabler_ref,
+				&event_notifier->enablers_ref_head, node) {
+			if (enabler_ref->ref->enabled) {
+				enabled = 1;
+				break;
+			}
+		}
+
+		CMM_STORE_SHARED(event_notifier->enabled, enabled);
+		/*
+		 * Sync tracepoint registration with event_notifier enabled
+		 * state.
+		 */
+		if (enabled) {
+			if (!event_notifier->registered)
+				register_event_notifier(event_notifier);
 		} else {
-			if (event->registered)
-				unregister_event(event);
+			if (event_notifier->registered)
+				unregister_event_notifier(event_notifier);
 		}
 
 		/* Check if has enablers without bytecode enabled */
 		cds_list_for_each_entry(enabler_ref,
-				&event->enablers_ref_head, node) {
+				&event_notifier->enablers_ref_head, node) {
 			if (enabler_ref->ref->enabled
 					&& cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
 				has_enablers_without_bytecode = 1;
 				break;
 			}
 		}
-		event->has_enablers_without_bytecode =
+		event_notifier->has_enablers_without_bytecode =
 			has_enablers_without_bytecode;
 
 		/* Enable filters */
 		cds_list_for_each_entry(runtime,
-				&event->bytecode_runtime_head, node) {
-			lttng_filter_sync_state(runtime);
+				&event_notifier->filter_bytecode_runtime_head, node) {
+			lttng_bytecode_filter_sync_state(runtime);
+		}
+
+		/* Enable captures. */
+		cds_list_for_each_entry(runtime,
+				&event_notifier->capture_bytecode_runtime_head, node) {
+			lttng_bytecode_capture_sync_state(runtime);
 		}
 	}
 	__tracepoint_probe_prune_release_queue();
@@ -1342,28 +1969,56 @@ void lttng_ust_context_set_session_provider(const char *name,
 		void (*get_value)(struct lttng_ctx_field *field,
 			struct lttng_ctx_value *value))
 {
-	struct lttng_session *session;
+	struct lttng_ust_session_private *session_priv;
 
-	cds_list_for_each_entry(session, &sessions, node) {
+	cds_list_for_each_entry(session_priv, &sessions, node) {
 		struct lttng_channel *chan;
-		struct lttng_event *event;
+		struct lttng_ust_event_private *event_priv;
 		int ret;
 
-		ret = lttng_ust_context_set_provider_rcu(&session->ctx,
+		ret = lttng_ust_context_set_provider_rcu(&session_priv->ctx,
 				name, get_size, record, get_value);
 		if (ret)
 			abort();
-		cds_list_for_each_entry(chan, &session->chan_head, node) {
+		cds_list_for_each_entry(chan, &session_priv->chan_head, node) {
 			ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
 					name, get_size, record, get_value);
 			if (ret)
 				abort();
 		}
-		cds_list_for_each_entry(event, &session->events_head, node) {
-			ret = lttng_ust_context_set_provider_rcu(&event->ctx,
+		cds_list_for_each_entry(event_priv, &session_priv->events_head, node) {
+			ret = lttng_ust_context_set_provider_rcu(&event_priv->pub->ctx,
 					name, get_size, record, get_value);
 			if (ret)
 				abort();
 		}
 	}
 }
+
+/*
+ * Update all event_notifier groups with the given app context.
+ * Called with ust lock held.
+ * This is invoked when an application context gets loaded/unloaded. It
+ * ensures the context callbacks are in sync with the application
+ * context (either app context callbacks, or dummy callbacks).
+ */
+void lttng_ust_context_set_event_notifier_group_provider(const char *name,
+		size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
+		void (*record)(struct lttng_ctx_field *field,
+			struct lttng_ust_lib_ring_buffer_ctx *ctx,
+			struct lttng_channel *chan),
+		void (*get_value)(struct lttng_ctx_field *field,
+			struct lttng_ctx_value *value))
+{
+	struct lttng_event_notifier_group *event_notifier_group;
+
+	cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
+		int ret;
+
+		ret = lttng_ust_context_set_provider_rcu(
+				&event_notifier_group->ctx,
+				name, get_size, record, get_value);
+		if (ret)
+			abort();
+	}
+}