X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-events.c;h=7afee7fc4043ac58a1be6a46df6852a93e10882c;hb=8306baea3da8b1f429e14218b1ef7413ee56ed19;hp=939dcd8627f340793d838140a20a24bc847c77dc;hpb=89f26d57d2880f83c9fee7fbc6ec870d1def0d2c;p=lttng-ust.git

diff --git a/liblttng-ust/lttng-events.c b/liblttng-ust/lttng-events.c
index 939dcd86..7afee7fc 100644
--- a/liblttng-ust/lttng-events.c
+++ b/liblttng-ust/lttng-events.c
@@ -21,6 +21,7 @@
  */
 
 #define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <stdio.h>
 #include <urcu/list.h>
 #include <urcu/hlist.h>
@@ -32,6 +33,7 @@
 #include <stddef.h>
 #include <inttypes.h>
 #include <time.h>
+#include <stdbool.h>
 #include <lttng/ust-endian.h>
 #include "clock.h"
 
@@ -47,14 +49,17 @@
 #include <helper.h>
 #include <lttng/ust-ctl.h>
 #include <ust-comm.h>
+#include <lttng/ust-dynamic-type.h>
+#include <lttng/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-tracer.h"
 #include "lttng-tracer-core.h"
-#include "lttng-ust-baddr.h"
+#include "lttng-ust-statedump.h"
 #include "wait.h"
 #include "../libringbuffer/shm.h"
 #include "jhash.h"
@@ -72,6 +77,7 @@ struct cds_list_head *_lttng_get_sessions(void)
 }
 
 static void _lttng_event_destroy(struct lttng_event *event);
+static void _lttng_enum_destroy(struct lttng_enum *_enum);
 
 static
 void lttng_session_lazy_sync_enablers(struct lttng_session *session);
@@ -137,11 +143,18 @@ struct lttng_session *lttng_session_create(void)
 	session = zmalloc(sizeof(struct lttng_session));
 	if (!session)
 		return NULL;
+	if (lttng_session_context_init(&session->ctx)) {
+		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);
 	for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 		CDS_INIT_HLIST_HEAD(&session->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);
 	return session;
 }
@@ -174,7 +187,7 @@ void register_event(struct lttng_event *event)
 
 	assert(event->registered == 0);
 	desc = event->desc;
-	ret = __tracepoint_probe_register(desc->name,
+	ret = __tracepoint_probe_register_queue_release(desc->name,
 			desc->probe_callback,
 			event, desc->signature);
 	WARN_ON_ONCE(ret);
@@ -190,7 +203,7 @@ void unregister_event(struct lttng_event *event)
 
 	assert(event->registered == 1);
 	desc = event->desc;
-	ret = __tracepoint_probe_unregister(desc->name,
+	ret = __tracepoint_probe_unregister_queue_release(desc->name,
 			desc->probe_callback,
 			event);
 	WARN_ON_ONCE(ret);
@@ -212,6 +225,7 @@ void lttng_session_destroy(struct lttng_session *session)
 {
 	struct lttng_channel *chan, *tmpchan;
 	struct lttng_event *event, *tmpevent;
+	struct lttng_enum *_enum, *tmp_enum;
 	struct lttng_enabler *enabler, *tmpenabler;
 
 	CMM_ACCESS_ONCE(session->active) = 0;
@@ -219,18 +233,170 @@ void lttng_session_destroy(struct lttng_session *session)
 		_lttng_event_unregister(event);
 	}
 	synchronize_trace();	/* Wait for in-flight events to complete */
+	__tracepoint_probe_prune_release_queue();
 	cds_list_for_each_entry_safe(enabler, tmpenabler,
 			&session->enablers_head, node)
 		lttng_enabler_destroy(enabler);
 	cds_list_for_each_entry_safe(event, tmpevent,
 			&session->events_head, node)
 		_lttng_event_destroy(event);
+	cds_list_for_each_entry_safe(_enum, tmp_enum,
+			&session->enums_head, node)
+		_lttng_enum_destroy(_enum);
 	cds_list_for_each_entry_safe(chan, tmpchan, &session->chan_head, node)
 		_lttng_channel_unmap(chan);
 	cds_list_del(&session->node);
+	lttng_destroy_context(session->ctx);
 	free(session);
 }
 
+static
+int lttng_enum_create(const struct lttng_enum_desc *desc,
+		struct lttng_session *session)
+{
+	const char *enum_name = desc->name;
+	struct lttng_enum *_enum;
+	struct cds_hlist_head *head;
+	int ret = 0;
+	size_t name_len = strlen(enum_name);
+	uint32_t hash;
+	int notify_socket;
+
+	/* 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)];
+
+	_enum = lttng_ust_enum_get_from_desc(session, desc);
+	if (_enum) {
+		ret = -EEXIST;
+		goto exist;
+	}
+
+	notify_socket = lttng_get_notify_socket(session->owner);
+	if (notify_socket < 0) {
+		ret = notify_socket;
+		goto socket_error;
+	}
+
+	_enum = zmalloc(sizeof(*_enum));
+	if (!_enum) {
+		ret = -ENOMEM;
+		goto cache_error;
+	}
+	_enum->session = session;
+	_enum->desc = desc;
+
+	ret = ustcomm_register_enum(notify_socket,
+		session->objd,
+		enum_name,
+		desc->nr_entries,
+		desc->entries,
+		&_enum->id);
+	if (ret < 0) {
+		DBG("Error (%d) registering enumeration to sessiond", ret);
+		goto sessiond_register_error;
+	}
+	cds_list_add(&_enum->node, &session->enums_head);
+	cds_hlist_add_head(&_enum->hlist, head);
+	return 0;
+
+sessiond_register_error:
+	free(_enum);
+cache_error:
+socket_error:
+exist:
+	return ret;
+}
+
+static
+int lttng_create_enum_check(const struct lttng_type *type,
+		struct lttng_session *session)
+{
+	switch (type->atype) {
+	case atype_enum:
+	{
+		const struct lttng_enum_desc *enum_desc;
+		int ret;
+
+		enum_desc = type->u.basic.enumeration.desc;
+		ret = lttng_enum_create(enum_desc, session);
+		if (ret && ret != -EEXIST) {
+			DBG("Unable to create enum error: (%d)", ret);
+			return ret;
+		}
+		break;
+	}
+	case atype_dynamic:
+	{
+		const struct lttng_event_field *tag_field_generic;
+		const struct lttng_enum_desc *enum_desc;
+		int ret;
+
+		tag_field_generic = lttng_ust_dynamic_type_tag_field();
+		enum_desc = tag_field_generic->type.u.basic.enumeration.desc;
+		ret = lttng_enum_create(enum_desc, session);
+		if (ret && ret != -EEXIST) {
+			DBG("Unable to create enum error: (%d)", ret);
+			return ret;
+		}
+		break;
+	}
+	default:
+		/* TODO: nested types when they become supported. */
+		break;
+	}
+	return 0;
+}
+
+static
+int lttng_create_all_event_enums(size_t nr_fields,
+		const struct lttng_event_field *event_fields,
+		struct lttng_session *session)
+{
+	size_t i;
+	int ret;
+
+	/* For each field, ensure enum is part of the session. */
+	for (i = 0; i < nr_fields; i++) {
+		const struct lttng_type *type = &event_fields[i].type;
+
+		ret = lttng_create_enum_check(type, session);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+static
+int lttng_create_all_ctx_enums(size_t nr_fields,
+		const struct lttng_ctx_field *ctx_fields,
+		struct lttng_session *session)
+{
+	size_t i;
+	int ret;
+
+	/* For each field, ensure enum is part of the session. */
+	for (i = 0; i < nr_fields; i++) {
+		const struct lttng_type *type = &ctx_fields[i].event_field.type;
+
+		ret = lttng_create_enum_check(type, session);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+/*
+ * Ensure that a state-dump will be performed for this session at the end
+ * of the current handle_message().
+ */
+int lttng_session_statedump(struct lttng_session *session)
+{
+	session->statedump_pending = 1;
+	lttng_ust_sockinfo_session_enabled(session->owner);
+	return 0;
+}
+
 int lttng_session_enable(struct lttng_session *session)
 {
 	int ret = 0;
@@ -249,6 +415,9 @@ int lttng_session_enable(struct lttng_session *session)
 	/* Set transient enabler state to "enabled" */
 	session->tstate = 1;
 
+	/* We need to sync enablers with session before activation. */
+	lttng_session_sync_enablers(session);
+
 	/*
 	 * Snapshot the number of events per channel to know the type of header
 	 * we need to use.
@@ -266,8 +435,15 @@ int lttng_session_enable(struct lttng_session *session)
 		if (ctx) {
 			nr_fields = ctx->nr_fields;
 			fields = ctx->fields;
+			ret = lttng_create_all_ctx_enums(nr_fields, fields,
+				session);
+			if (ret < 0) {
+				DBG("Error (%d) adding enum to session", ret);
+				return ret;
+			}
 		}
 		ret = ustcomm_register_channel(notify_socket,
+			session,
 			session->objd,
 			chan->objd,
 			nr_fields,
@@ -285,15 +461,13 @@ int lttng_session_enable(struct lttng_session *session)
 		}
 	}
 
-	/* We need to sync enablers with session before activation. */
-	lttng_session_sync_enablers(session);
-
 	/* Set atomically the state to "active" */
 	CMM_ACCESS_ONCE(session->active) = 1;
 	CMM_ACCESS_ONCE(session->been_active) = 1;
 
-	session->statedump_pending = 1;
-	lttng_ust_sockinfo_session_enabled(session->owner);
+	ret = lttng_session_statedump(session);
+	if (ret)
+		return ret;
 end:
 	return ret;
 }
@@ -361,7 +535,6 @@ int lttng_event_create(const struct lttng_event_desc *desc,
 	struct lttng_event *event;
 	struct lttng_session *session = chan->session;
 	struct cds_hlist_head *head;
-	struct cds_hlist_node *node;
 	int ret = 0;
 	size_t name_len = strlen(event_name);
 	uint32_t hash;
@@ -370,15 +543,6 @@ int lttng_event_create(const struct lttng_event_desc *desc,
 
 	hash = jhash(event_name, name_len, 0);
 	head = &chan->session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
-	cds_hlist_for_each_entry(event, node, head, hlist) {
-		assert(event->desc);
-		if (!strncmp(event->desc->name, desc->name,
-					LTTNG_UST_SYM_NAME_LEN - 1)
-				&& chan == event->chan) {
-			ret = -EEXIST;
-			goto exist;
-		}
-	}
 
 	notify_socket = lttng_get_notify_socket(session->owner);
 	if (notify_socket < 0) {
@@ -386,6 +550,13 @@ int lttng_event_create(const struct lttng_event_desc *desc,
 		goto socket_error;
 	}
 
+	ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
+			session);
+	if (ret < 0) {
+		DBG("Error (%d) adding enum to session", ret);
+		goto create_enum_error;
+	}
+
 	/*
 	 * Check if loglevel match. Refuse to connect event if not.
 	 */
@@ -414,6 +585,7 @@ int lttng_event_create(const struct lttng_event_desc *desc,
 
 	/* Fetch event ID from sessiond */
 	ret = ustcomm_register_event(notify_socket,
+		session,
 		session->objd,
 		chan->objd,
 		event_name,
@@ -428,8 +600,6 @@ int lttng_event_create(const struct lttng_event_desc *desc,
 		goto sessiond_register_error;
 	}
 
-	/* Populate lttng_event structure before tracepoint registration. */
-	cmm_smp_wmb();
 	cds_list_add(&event->node, &chan->session->events_head);
 	cds_hlist_add_head(&event->hlist, head);
 	return 0;
@@ -437,22 +607,21 @@ int lttng_event_create(const struct lttng_event_desc *desc,
 sessiond_register_error:
 	free(event);
 cache_error:
+create_enum_error:
 socket_error:
-exist:
 	return ret;
 }
 
 static
-int lttng_desc_match_wildcard_enabler(const struct lttng_event_desc *desc,
+int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 		struct lttng_enabler *enabler)
 {
 	int loglevel = 0;
 	unsigned int has_loglevel = 0;
 
-	assert(enabler->type == LTTNG_ENABLER_WILDCARD);
-	/* Compare excluding final '*' */
-	if (strncmp(desc->name, enabler->event_param.name,
-			strlen(enabler->event_param.name) - 1))
+	assert(enabler->type == LTTNG_ENABLER_STAR_GLOB);
+	if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
+			desc->name, SIZE_MAX))
 		return 0;
 	if (desc->loglevel) {
 		loglevel = *(*desc->loglevel);
@@ -492,34 +661,35 @@ static
 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
 		struct lttng_enabler *enabler)
 {
-	struct lttng_ust_excluder_node *excluder;
-
-	/* If event matches with an excluder, return 'does not match' */
-	cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
-		int count;
-
-		for (count = 0; count < excluder->excluder.count; count++) {
-			int found, len;
-			char *excluder_name;
-
-			excluder_name = (char *) (excluder->excluder.names)
-					+ count * LTTNG_UST_SYM_NAME_LEN;
-			len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
-			if (len > 0 && excluder_name[len - 1] == '*') {
-				found = !strncmp(desc->name, excluder_name,
-						len - 1);
-			} else {
-				found = !strncmp(desc->name, excluder_name,
-						LTTNG_UST_SYM_NAME_LEN - 1);
-			}
-			if (found) {
-				return 0;
+	switch (enabler->type) {
+	case LTTNG_ENABLER_STAR_GLOB:
+	{
+		struct lttng_ust_excluder_node *excluder;
+
+		if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
+			return 0;
+		}
+
+		/*
+		 * If the matching event matches with an excluder,
+		 * return 'does not match'
+		 */
+		cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
+			int count;
+
+			for (count = 0; count < excluder->excluder.count; count++) {
+				int len;
+				char *excluder_name;
+
+				excluder_name = (char *) (excluder->excluder.names)
+						+ count * LTTNG_UST_SYM_NAME_LEN;
+				len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
+				if (len > 0 && strutils_star_glob_match(excluder_name, len, desc->name, SIZE_MAX))
+					return 0;
 			}
 		}
+		return 1;
 	}
-	switch (enabler->type) {
-	case LTTNG_ENABLER_WILDCARD:
-		return lttng_desc_match_wildcard_enabler(desc, enabler);
 	case LTTNG_ENABLER_EVENT:
 		return lttng_desc_match_event_enabler(desc, enabler);
 	default:
@@ -614,6 +784,111 @@ void lttng_create_event_if_missing(struct lttng_enabler *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)
+{
+	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;
+
+	/* Get handle on list of sessions. */
+	sessionsp = _lttng_get_sessions();
+
+	/*
+	 * 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;
+		const char *event_name;
+		size_t name_len;
+		uint32_t hash;
+
+		event_desc = provider_desc->event_desc[i];
+		event_name = event_desc->name;
+		name_len = strlen(event_name);
+		hash = jhash(event_name, name_len, 0);
+
+		/* Iterate over all session to find the current event description. */
+		cds_list_for_each_entry(session, sessionsp, node) {
+			/*
+			 * Get the list of events in the hashtable bucket and iterate to
+			 * find the event matching this descriptor.
+			 */
+			head = &session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
+			cds_hlist_for_each_entry(event, node, head, hlist) {
+				if (event_desc == event->desc) {
+					/* Queue the unregistration of this event. */
+					_lttng_event_unregister(event);
+					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;
+		const char *event_name;
+		size_t name_len;
+		uint32_t hash;
+
+		event_desc = provider_desc->event_desc[i];
+		event_name = event_desc->name;
+		name_len = strlen(event_name);
+		hash = jhash(event_name, name_len, 0);
+
+		/* Iterate over all sessions to find the current event description. */
+		cds_list_for_each_entry(session, sessionsp, node) {
+			/*
+			 * Get the list of events in the hashtable bucket and iterate to
+			 * find the event matching this descriptor.
+			 */
+			head = &session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
+			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]);
+						if (field->type.atype != atype_enum) {
+							continue;
+						}
+
+						enum_desc = field->type.u.basic.enumeration.desc;
+						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);
+					break;
+				}
+			}
+		}
+	}
+}
+
 /*
  * Create events associated with an enabler (if not already present),
  * and add backward reference from the event to the enabler.
@@ -683,7 +958,7 @@ void lttng_handle_pending_statedump(void *owner)
 	struct lttng_session *session;
 
 	/* Execute state dump */
-	lttng_ust_baddr_statedump(owner);
+	do_lttng_ust_statedump(owner);
 
 	/* Clear pending state dump */
 	if (ust_lock()) {
@@ -709,7 +984,11 @@ 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);
+	/* Remove from event hash table. */
+	cds_hlist_del(&event->hlist);
+
 	lttng_destroy_context(event->ctx);
 	lttng_free_event_filter_runtime(event);
 	/* Free event enabler refs */
@@ -719,6 +998,14 @@ void _lttng_event_destroy(struct lttng_event *event)
 	free(event);
 }
 
+static
+void _lttng_enum_destroy(struct lttng_enum *_enum)
+{
+	cds_list_del(&_enum->node);
+	cds_hlist_del(&_enum->hlist);
+	free(_enum);
+}
+
 void lttng_ust_events_exit(void)
 {
 	struct lttng_session *session, *tmpsession;
@@ -785,6 +1072,7 @@ int lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
 }
 
 int lttng_attach_context(struct lttng_ust_context *context_param,
+		union ust_args *uargs,
 		struct lttng_ctx **ctx, struct lttng_session *session)
 {
 	/*
@@ -817,6 +1105,37 @@ int lttng_attach_context(struct lttng_ust_context *context_param,
 		return lttng_add_procname_to_ctx(ctx);
 	case LTTNG_UST_CONTEXT_IP:
 		return lttng_add_ip_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_CPU_ID:
+		return lttng_add_cpu_id_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_APP_CONTEXT:
+		return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
+			ctx);
+	case LTTNG_UST_CONTEXT_CGROUP_NS:
+		return lttng_add_cgroup_ns_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_IPC_NS:
+		return lttng_add_ipc_ns_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_MNT_NS:
+		return lttng_add_mnt_ns_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_NET_NS:
+		return lttng_add_net_ns_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_PID_NS:
+		return lttng_add_pid_ns_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_USER_NS:
+		return lttng_add_user_ns_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_UTS_NS:
+		return lttng_add_uts_ns_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_VUID:
+		return lttng_add_vuid_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_VEUID:
+		return lttng_add_veuid_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_VSUID:
+		return lttng_add_vsuid_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_VGID:
+		return lttng_add_vgid_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_VEGID:
+		return lttng_add_vegid_to_ctx(ctx);
+	case LTTNG_UST_CONTEXT_VSGID:
+		return lttng_add_vsgid_to_ctx(ctx);
 	default:
 		return -EINVAL;
 	}
@@ -931,6 +1250,7 @@ void lttng_session_sync_enablers(struct lttng_session *session)
 			lttng_filter_sync_state(runtime);
 		}
 	}
+	__tracepoint_probe_prune_release_queue();
 }
 
 /*
@@ -947,3 +1267,44 @@ void lttng_session_lazy_sync_enablers(struct lttng_session *session)
 		return;
 	lttng_session_sync_enablers(session);
 }
+
+/*
+ * Update all sessions 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_session_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_session *session;
+
+	cds_list_for_each_entry(session, &sessions, node) {
+		struct lttng_channel *chan;
+		struct lttng_event *event;
+		int ret;
+
+		ret = lttng_ust_context_set_provider_rcu(&session->ctx,
+				name, get_size, record, get_value);
+		if (ret)
+			abort();
+		cds_list_for_each_entry(chan, &session->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,
+					name, get_size, record, get_value);
+			if (ret)
+				abort();
+		}
+	}
+}