X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;ds=sidebyside;f=liblttng-ust%2Flttng-probes.c;h=b1d5fe28558433209f70460119125ca81b433793;hb=ff51799104d4b7255b7e00c839260fd4650e5113;hp=e473b9890c9395f73121736a6dc6333399e373a1;hpb=7dd08bec735b428479201f9f84d59c78deabdf57;p=lttng-ust.git

diff --git a/liblttng-ust/lttng-probes.c b/liblttng-ust/lttng-probes.c
index e473b989..b1d5fe28 100644
--- a/liblttng-ust/lttng-probes.c
+++ b/liblttng-ust/lttng-probes.c
@@ -38,63 +38,70 @@
 /*
  * probe list is protected by ust_lock()/ust_unlock().
  */
-static CDS_LIST_HEAD(probe_list);
+static CDS_LIST_HEAD(_probe_list);
 
-static
-const struct lttng_probe_desc *find_provider(const char *provider)
-{
-	struct lttng_probe_desc *iter;
+/*
+ * List of probes registered by not yet processed.
+ */
+static CDS_LIST_HEAD(lazy_probe_init);
 
-	cds_list_for_each_entry(iter, &probe_list, head) {
-		if (!strcmp(iter->provider, provider))
-			return iter;
-	}
-	return NULL;
-}
+/*
+ * lazy_nesting counter ensures we don't trigger lazy probe registration
+ * fixup while we are performing the fixup. It is protected by the ust
+ * mutex.
+ */
+static int lazy_nesting;
 
+/*
+ * Called under ust lock.
+ */
 static
-const struct lttng_event_desc *find_event(const char *name)
+int check_event_provider(struct lttng_probe_desc *desc)
 {
-	struct lttng_probe_desc *probe_desc;
 	int i;
+	size_t provider_name_len;
 
-	cds_list_for_each_entry(probe_desc, &probe_list, head) {
-		for (i = 0; i < probe_desc->nr_events; i++) {
-			if (!strncmp(probe_desc->event_desc[i]->name, name,
-					LTTNG_UST_SYM_NAME_LEN - 1))
-				return probe_desc->event_desc[i];
-		}
+	provider_name_len = strnlen(desc->provider,
+				LTTNG_UST_SYM_NAME_LEN - 1);
+	for (i = 0; i < desc->nr_events; i++) {
+		if (strncmp(desc->event_desc[i]->name,
+				desc->provider,
+				provider_name_len))
+			return 0;	/* provider mismatch */
 	}
-	return NULL;
+	return 1;
 }
 
-int lttng_probe_register(struct lttng_probe_desc *desc)
+/*
+ * Called under ust lock.
+ */
+static
+void lttng_lazy_probe_register(struct lttng_probe_desc *desc)
 {
 	struct lttng_probe_desc *iter;
-	int ret = 0;
+	struct cds_list_head *probe_list;
 	int i;
 
-	ust_lock();
-	if (find_provider(desc->provider)) {
-		ret = -EEXIST;
-		goto end;
-	}
 	/*
-	 * TODO: This is O(N^2). Turn into a hash table when probe registration
-	 * overhead becomes an issue.
+	 * Each provider enforce that every event name begins with the
+	 * provider name. Check this in an assertion for extra
+	 * carefulness. This ensures we cannot have duplicate event
+	 * names across providers.
+	 */
+	assert(check_event_provider(desc));
+
+	/*
+	 * The provider ensures there are no duplicate event names.
+	 * Duplicated TRACEPOINT_EVENT event names would generate a
+	 * compile-time error due to duplicated symbol names.
 	 */
-	for (i = 0; i < desc->nr_events; i++) {
-		if (find_event(desc->event_desc[i]->name)) {
-			ret = -EEXIST;
-			goto end;
-		}
-	}
 
 	/*
 	 * We sort the providers by struct lttng_probe_desc pointer
 	 * address.
 	 */
-	cds_list_for_each_entry_reverse(iter, &probe_list, head) {
+	probe_list = &_probe_list;
+	cds_list_for_each_entry_reverse(iter, probe_list, head) {
 		BUG_ON(iter == desc); /* Should never be in the list twice */
 		if (iter < desc) {
 			/* We belong to the location right after iter. */
@@ -103,7 +110,7 @@ int lttng_probe_register(struct lttng_probe_desc *desc)
 		}
 	}
 	/* We should be added at the head of the list */
-	cds_list_add(&desc->head, &probe_list);
+	cds_list_add(&desc->head, probe_list);
 desc_added:
 	DBG("just registered probe %s containing %u events",
 		desc->provider, desc->nr_events);
@@ -112,13 +119,82 @@ desc_added:
 	 */
 	for (i = 0; i < desc->nr_events; i++) {
 		const struct lttng_event_desc *ed;
+		int ret;
 
 		ed = desc->event_desc[i];
 		DBG("Registered event probe \"%s\" with signature \"%s\"",
 			ed->name, ed->signature);
-		ret = pending_probe_fix_events(ed);
+		ret = lttng_fix_pending_event_desc(ed);
 		assert(!ret);
 	}
+}
+
+/*
+ * Called under ust lock.
+ */
+static
+void fixup_lazy_probes(void)
+{
+	struct lttng_probe_desc *iter, *tmp;
+
+	lazy_nesting++;
+	cds_list_for_each_entry_safe(iter, tmp,
+			&lazy_probe_init, lazy_init_head) {
+		lttng_lazy_probe_register(iter);
+		iter->lazy = 0;
+		cds_list_del(&iter->lazy_init_head);
+	}
+	lazy_nesting--;
+}
+
+/*
+ * Called under ust lock.
+ */
+struct cds_list_head *lttng_get_probe_list_head(void)
+{
+	if (!lazy_nesting && !cds_list_empty(&lazy_probe_init))
+		fixup_lazy_probes();
+	return &_probe_list;
+}
+
+static
+const struct lttng_probe_desc *find_provider(const char *provider)
+{
+	struct lttng_probe_desc *iter;
+	struct cds_list_head *probe_list;
+
+	probe_list = lttng_get_probe_list_head();
+	cds_list_for_each_entry(iter, probe_list, head) {
+		if (!strcmp(iter->provider, provider))
+			return iter;
+	}
+	return NULL;
+}
+
+int lttng_probe_register(struct lttng_probe_desc *desc)
+{
+	int ret = 0;
+
+	ust_lock();
+
+	/*
+	 * Check if the provider has already been registered.
+	 */
+	if (find_provider(desc->provider)) {
+		ret = -EEXIST;
+		goto end;
+	}
+	cds_list_add(&desc->lazy_init_head, &lazy_probe_init);
+	desc->lazy = 1;
+	DBG("adding probe %s containing %u events to lazy registration list",
+		desc->provider, desc->nr_events);
+	/*
+	 * If there is at least one active session, we need to register
+	 * the probe immediately, since we cannot delay event
+	 * registration because they are needed ASAP.
+	 */
+	if (lttng_session_active())
+		fixup_lazy_probes();
 end:
 	ust_unlock();
 	return ret;
@@ -133,7 +209,10 @@ int ltt_probe_register(struct lttng_probe_desc *desc)
 void lttng_probe_unregister(struct lttng_probe_desc *desc)
 {
 	ust_lock();
-	cds_list_del(&desc->head);
+	if (!desc->lazy)
+		cds_list_del(&desc->head);
+	else
+		cds_list_del(&desc->lazy_init_head);
 	DBG("just unregistered probe %s", desc->provider);
 	ust_unlock();
 }
@@ -144,23 +223,6 @@ void ltt_probe_unregister(struct lttng_probe_desc *desc)
 	lttng_probe_unregister(desc);
 }
 
-/*
- * called with UST lock held.
- */
-const struct lttng_event_desc *lttng_event_get(const char *name)
-{
-	const struct lttng_event_desc *event;
-
-	event = find_event(name);
-	if (!event)
-		return NULL;
-	return event;
-}
-
-void lttng_event_put(const struct lttng_event_desc *event)
-{
-}
-
 void lttng_probes_prune_event_list(struct lttng_ust_tracepoint_list *list)
 {
 	struct tp_list_entry *list_entry, *tmp;
@@ -178,9 +240,11 @@ int lttng_probes_get_event_list(struct lttng_ust_tracepoint_list *list)
 {
 	struct lttng_probe_desc *probe_desc;
 	int i;
+	struct cds_list_head *probe_list;
 
+	probe_list = lttng_get_probe_list_head();
 	CDS_INIT_LIST_HEAD(&list->head);
-	cds_list_for_each_entry(probe_desc, &probe_list, head) {
+	cds_list_for_each_entry(probe_desc, probe_list, head) {
 		for (i = 0; i < probe_desc->nr_events; i++) {
 			struct tp_list_entry *list_entry;
 
@@ -248,9 +312,11 @@ int lttng_probes_get_field_list(struct lttng_ust_field_list *list)
 {
 	struct lttng_probe_desc *probe_desc;
 	int i;
+	struct cds_list_head *probe_list;
 
+	probe_list = lttng_get_probe_list_head();
 	CDS_INIT_LIST_HEAD(&list->head);
-	cds_list_for_each_entry(probe_desc, &probe_list, head) {
+	cds_list_for_each_entry(probe_desc, probe_list, head) {
 		for (i = 0; i < probe_desc->nr_events; i++) {
 			const struct lttng_event_desc *event_desc =
 				probe_desc->event_desc[i];
@@ -366,58 +432,3 @@ struct lttng_ust_field_iter *
 				struct tp_field_list_entry, head);
 	return &entry->field;
 }
-
-/*
- * marshall all probes/all events and create those that fit the
- * wildcard. Add them to the events list as created.
- */
-void lttng_probes_create_wildcard_events(struct wildcard_entry *entry,
-				struct session_wildcard *wildcard)
-{
-	struct lttng_probe_desc *probe_desc;
-	struct lttng_ust_event event_param;
-	int i;
-
-	cds_list_for_each_entry(probe_desc, &probe_list, head) {
-		for (i = 0; i < probe_desc->nr_events; i++) {
-			const struct lttng_event_desc *event_desc;
-			int match = 0;
-
-			event_desc = probe_desc->event_desc[i];
-			/* compare excluding final '*' */
-			assert(strlen(entry->name) > 0);
-			if (strcmp(event_desc->name, "lttng_ust:metadata")
-					&& (strlen(entry->name) == 1
-						|| !strncmp(event_desc->name, entry->name,
-							strlen(entry->name) - 1))) {
-				if (lttng_loglevel_match(event_desc,
-					entry->loglevel_type,
-						entry->loglevel)) {
-					match = 1;
-				}
-			}
-			if (match) {
-				struct lttng_event *ev;
-				int ret;
-
-				memcpy(&event_param, &wildcard->event_param,
-						sizeof(event_param));
-				strncpy(event_param.name,
-					event_desc->name,
-					sizeof(event_param.name));
-				event_param.name[sizeof(event_param.name) - 1] = '\0';
-				/* create event */
-				ret = lttng_event_create(wildcard->chan,
-					&event_param, &ev);
-				if (ret) {
-					DBG("Error creating event");
-					continue;
-				}
-				cds_list_add(&ev->wildcard_list,
-					&wildcard->events);
-			}
-		}
-	}
-	lttng_filter_wildcard_link_bytecode(wildcard);
-}
-