[lttng-dev] [[RFC PATCH lttng-tools]] Fix: Disable all UST events matching the given name

[Jérémie Galarneau]

The session daemon will only disable the first event
matching the name provided to the disable-event command.
This fix iterates on all events matching the name, ignoring
their filter, loglevel and exclusion list.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau at efficios.com>
---
 src/bin/lttng-sessiond/ust-app.c | 78 +++++++++++++++++++++++++++++-----------
 1 file changed, 57 insertions(+), 21 deletions(-)

diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index 4066b06..02f6153 100644
--- a/src/bin/lttng-sessiond/ust-app.c
+++ b/src/bin/lttng-sessiond/ust-app.c
@@ -170,6 +170,34 @@ no_match:
 }
 
 /*
+ * Match function for the hash table lookup.
+ *
+ * Matches an ust app event based on its name only.
+ */
+static int ht_match_ust_app_event_by_name(struct cds_lfht_node *node,
+		const void *_key)
+{
+	struct ust_app_event *event;
+	const char *name;
+
+	assert(node);
+	assert(_key);
+
+	event = caa_container_of(node, struct ust_app_event, node.node);
+	name = _key;
+
+	if (strncmp(event->attr.name, name, sizeof(event->attr.name))) {
+		goto no_match;
+	}
+
+	/* Match. */
+	return 1;
+
+no_match:
+	return 0;
+}
+
+/*
  * Unique add of an ust app event in the given ht. This uses the custom
  * ht_match_ust_app_event match function and the event name as hash.
  */
@@ -3873,11 +3901,9 @@ int ust_app_disable_event_glb(struct ltt_ust_session *usess,
 {
 	int ret = 0;
 	struct lttng_ht_iter iter, uiter;
-	struct lttng_ht_node_str *ua_chan_node, *ua_event_node;
+	struct lttng_ht_node_str *ua_chan_node;
 	struct ust_app *app;
-	struct ust_app_session *ua_sess;
 	struct ust_app_channel *ua_chan;
-	struct ust_app_event *ua_event;
 
 	DBG("UST app disabling event %s for all apps in channel "
 			"%s for session id %" PRIu64,
@@ -3887,10 +3913,13 @@ int ust_app_disable_event_glb(struct ltt_ust_session *usess,
 
 	/* For all registered applications */
 	cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) {
+		struct ust_app_session *ua_sess;
+		struct cds_lfht_node *ua_event_node;
+
 		if (!app->compatible) {
 			/*
-			 * TODO: In time, we should notice the caller of this error by
-			 * telling him that this is a version error.
+			 * TODO: In time, we should notice the caller of this
+			 * error by telling him that this is a version error.
 			 */
 			continue;
 		}
@@ -3901,28 +3930,35 @@ int ust_app_disable_event_glb(struct ltt_ust_session *usess,
 		}
 
 		/* Lookup channel in the ust app session */
-		lttng_ht_lookup(ua_sess->channels, (void *)uchan->name, &uiter);
+		lttng_ht_lookup(ua_sess->channels, (void *) uchan->name,
+				&uiter);
 		ua_chan_node = lttng_ht_iter_get_node_str(&uiter);
-		if (ua_chan_node == NULL) {
+		if (!ua_chan_node) {
 			DBG2("Channel %s not found in session id %" PRIu64 " for app pid %d."
-					"Skipping", uchan->name, usess->id, app->pid);
+					"Skipping", uchan->name, usess->id,
+					app->pid);
 			continue;
 		}
 		ua_chan = caa_container_of(ua_chan_node, struct ust_app_channel, node);
 
-		lttng_ht_lookup(ua_chan->events, (void *)uevent->attr.name, &uiter);
-		ua_event_node = lttng_ht_iter_get_node_str(&uiter);
-		if (ua_event_node == NULL) {
-			DBG2("Event %s not found in channel %s for app pid %d."
-					"Skipping", uevent->attr.name, uchan->name, app->pid);
-			continue;
-		}
-		ua_event = caa_container_of(ua_event_node, struct ust_app_event, node);
-
-		ret = disable_ust_app_event(ua_sess, ua_event, app);
-		if (ret < 0) {
-			/* XXX: Report error someday... */
-			continue;
+		cds_lfht_for_each_duplicate(ua_chan->events->ht,
+				ua_chan->events->hash_fct(uevent->attr.name,
+					lttng_ht_seed),
+				ht_match_ust_app_event_by_name,
+				(void *) uevent->attr.name, &uiter.iter,
+				ua_event_node) {
+			struct ust_app_event *ua_event;
+
+			ua_event = caa_container_of(ua_event_node,
+					struct ust_app_event, node);
+			ret = disable_ust_app_event(ua_sess, ua_event, app);
+			if (ret < 0) {
+				DBG("Failed to disable event %s in channel %s "
+						"of app pid %d.",
+						uevent->attr.name,
+						uchan->name, app->pid);
+				continue;
+			}
 		}
 	}
 
-- 
2.5.2