X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fust-app.c;h=11dde04abaea1f112dcd171e988ab922ed6d5537;hb=fa7fee60cac8659b3a980a6400939a5a24e0e61e;hp=f8e96936d172f45ae85ac5a2980f8d2020a95a80;hpb=f14256d650ba78aa23c87a1f35c0c66656cb9e06;p=lttng-tools.git

diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
index f8e96936d..11dde04ab 100644
--- a/src/bin/lttng-sessiond/ust-app.c
+++ b/src/bin/lttng-sessiond/ust-app.c
@@ -1446,7 +1446,32 @@ int create_ust_event(struct ust_app *app, struct ust_app_session *ua_sess,
 	}
 
 	/* If event not enabled, disable it on the tracer */
-	if (ua_event->enabled == 0) {
+	if (ua_event->enabled) {
+		/*
+		 * We now need to explicitly enable the event, since it
+		 * is now disabled at creation.
+		 */
+		ret = enable_ust_event(app, ua_sess, ua_event);
+		if (ret < 0) {
+			/*
+			 * If we hit an EPERM, something is wrong with our enable call. If
+			 * we get an EEXIST, there is a problem on the tracer side since we
+			 * just created it.
+			 */
+			switch (ret) {
+			case -LTTNG_UST_ERR_PERM:
+				/* Code flow problem */
+				assert(0);
+			case -LTTNG_UST_ERR_EXIST:
+				/* It's OK for our use case. */
+				ret = 0;
+				break;
+			default:
+				break;
+			}
+			goto error;
+		}
+	} else {
 		ret = disable_ust_event(app, ua_sess, ua_event);
 		if (ret < 0) {
 			/*
@@ -1923,6 +1948,75 @@ error:
 	return ret;
 }
 
+/*
+ * Match function for a hash table lookup of ust_app_ctx.
+ *
+ * It matches an ust app context based on the context type and, in the case
+ * of perf counters, their name.
+ */
+static int ht_match_ust_app_ctx(struct cds_lfht_node *node, const void *_key)
+{
+	struct ust_app_ctx *ctx;
+	const struct lttng_ust_context *key;
+
+	assert(node);
+	assert(_key);
+
+	ctx = caa_container_of(node, struct ust_app_ctx, node.node);
+	key = _key;
+
+	/* Context type */
+	if (ctx->ctx.ctx != key->ctx) {
+		goto no_match;
+	}
+
+	/* Check the name in the case of perf thread counters. */
+	if (key->ctx == LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER) {
+		if (strncmp(key->u.perf_counter.name,
+			ctx->ctx.u.perf_counter.name,
+			sizeof(key->u.perf_counter.name))) {
+			goto no_match;
+		}
+	}
+
+	/* Match. */
+	return 1;
+
+no_match:
+	return 0;
+}
+
+/*
+ * Lookup for an ust app context from an lttng_ust_context.
+ *
+ * Must be called while holding RCU read side lock.
+ * Return an ust_app_ctx object or NULL on error.
+ */
+static
+struct ust_app_ctx *find_ust_app_context(struct lttng_ht *ht,
+		struct lttng_ust_context *uctx)
+{
+	struct lttng_ht_iter iter;
+	struct lttng_ht_node_ulong *node;
+	struct ust_app_ctx *app_ctx = NULL;
+
+	assert(uctx);
+	assert(ht);
+
+	/* Lookup using the lttng_ust_context_type and a custom match fct. */
+	cds_lfht_lookup(ht->ht, ht->hash_fct((void *) uctx->ctx, lttng_ht_seed),
+			ht_match_ust_app_ctx, uctx, &iter.iter);
+	node = lttng_ht_iter_get_node_ulong(&iter);
+	if (!node) {
+		goto end;
+	}
+
+	app_ctx = caa_container_of(node, struct ust_app_ctx, node);
+
+end:
+	return app_ctx;
+}
+
 /*
  * Create a context for the channel on the tracer.
  *
@@ -1934,15 +2028,12 @@ int create_ust_app_channel_context(struct ust_app_session *ua_sess,
 		struct ust_app *app)
 {
 	int ret = 0;
-	struct lttng_ht_iter iter;
-	struct lttng_ht_node_ulong *node;
 	struct ust_app_ctx *ua_ctx;
 
 	DBG2("UST app adding context to channel %s", ua_chan->name);
 
-	lttng_ht_lookup(ua_chan->ctx, (void *)((unsigned long)uctx->ctx), &iter);
-	node = lttng_ht_iter_get_node_ulong(&iter);
-	if (node != NULL) {
+	ua_ctx = find_ust_app_context(ua_chan->ctx, uctx);
+	if (ua_ctx) {
 		ret = -EEXIST;
 		goto error;
 	}
@@ -5081,10 +5172,12 @@ unsigned int ust_app_get_nb_stream(struct ltt_ust_session *usess)
 		cds_list_for_each_entry(reg, &usess->buffer_reg_uid_list, lnode) {
 			struct buffer_reg_channel *reg_chan;
 
+			rcu_read_lock();
 			cds_lfht_for_each_entry(reg->registry->channels->ht, &iter.iter,
 					reg_chan, node.node) {
 				ret += reg_chan->stream_count;
 			}
+			rcu_read_unlock();
 		}
 		break;
 	}