X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=lttng-sessiond%2Fust-app.c;h=77dcc71a6fee77bbcc28d1298eb90355566fb630;hb=6df2e2c977b698cc6b8f15c90b649516674028f9;hp=37dbfcb91922885f73482cf0b1b2f81edcd916be;hpb=55cc08a60ad1b188d59161842e630402e738e62e;p=lttng-tools.git

diff --git a/lttng-sessiond/ust-app.c b/lttng-sessiond/ust-app.c
index 37dbfcb91..77dcc71a6 100644
--- a/lttng-sessiond/ust-app.c
+++ b/lttng-sessiond/ust-app.c
@@ -53,7 +53,8 @@ void delete_ust_app_ctx(int sock, struct ust_app_ctx *ua_ctx)
  * Delete ust app event safely. RCU read lock must be held before calling
  * this function.
  */
-static void delete_ust_app_event(int sock, struct ust_app_event *ua_event)
+static
+void delete_ust_app_event(int sock, struct ust_app_event *ua_event)
 {
 	int ret;
 	struct cds_lfht_iter iter;
@@ -78,10 +79,13 @@ static void delete_ust_app_event(int sock, struct ust_app_event *ua_event)
  * Delete ust app stream safely. RCU read lock must be held before calling
  * this function.
  */
-static void delete_ust_app_stream(int sock, struct ltt_ust_stream *stream)
+static
+void delete_ust_app_stream(int sock, struct ltt_ust_stream *stream)
 {
-	ustctl_release_object(sock, stream->obj);
-	free(stream->obj);
+	if (stream->obj) {
+		ustctl_release_object(sock, stream->obj);
+		free(stream->obj);
+	}
 	free(stream);
 }
 
@@ -89,7 +93,8 @@ static void delete_ust_app_stream(int sock, struct ltt_ust_stream *stream)
  * Delete ust app channel safely. RCU read lock must be held before calling
  * this function.
  */
-static void delete_ust_app_channel(int sock, struct ust_app_channel *ua_chan)
+static
+void delete_ust_app_channel(int sock, struct ust_app_channel *ua_chan)
 {
 	int ret;
 	struct cds_lfht_iter iter;
@@ -132,18 +137,22 @@ static void delete_ust_app_channel(int sock, struct ust_app_channel *ua_chan)
  * Delete ust app session safely. RCU read lock must be held before calling
  * this function.
  */
-static void delete_ust_app_session(int sock,
-		struct ust_app_session *ua_sess)
+static
+void delete_ust_app_session(int sock, struct ust_app_session *ua_sess)
 {
 	int ret;
 	struct cds_lfht_iter iter;
 	struct ust_app_channel *ua_chan;
 
 	if (ua_sess->metadata) {
-		ustctl_release_object(sock, ua_sess->metadata->stream_obj);
-		free(ua_sess->metadata->stream_obj);
-		ustctl_release_object(sock, ua_sess->metadata->obj);
-		free(ua_sess->metadata->obj);
+		if (ua_sess->metadata->stream_obj) {
+			ustctl_release_object(sock, ua_sess->metadata->stream_obj);
+			free(ua_sess->metadata->stream_obj);
+		}
+		if (ua_sess->metadata->obj) {
+			ustctl_release_object(sock, ua_sess->metadata->obj);
+			free(ua_sess->metadata->obj);
+		}
 	}
 
 	cds_lfht_for_each_entry(ua_sess->channels, &iter, ua_chan, node) {
@@ -151,28 +160,26 @@ static void delete_ust_app_session(int sock,
 		assert(!ret);
 		delete_ust_app_channel(sock, ua_chan);
 	}
-
 	ret = hashtable_destroy(ua_sess->channels);
-	if (ret < 0) {
-		ERR("UST app destroy session hashtable failed");
-		goto error;
-	}
+	assert(!ret);
 
-error:
-	return;
+	if (ua_sess->handle != -1) {
+		ustctl_release_handle(sock, ua_sess->handle);
+	}
+	free(ua_sess);
 }
 
 /*
  * Delete a traceable application structure from the global list. Never call
  * this function outside of a call_rcu call.
  */
-static void delete_ust_app(struct ust_app *app)
+static
+void delete_ust_app(struct ust_app *app)
 {
-	int ret;
+	int ret, sock;
 	struct cds_lfht_node *node;
 	struct cds_lfht_iter iter;
 	struct ust_app_session *ua_sess;
-	int sock;
 
 	rcu_read_lock();
 
@@ -200,17 +207,14 @@ static void delete_ust_app(struct ust_app *app)
 	sock = app->key.sock;
 	app->key.sock = -1;
 
+	/* Wipe sessions */
 	cds_lfht_for_each_entry(app->sessions, &iter, ua_sess, node) {
 		ret = hashtable_del(app->sessions, &iter);
 		assert(!ret);
 		delete_ust_app_session(app->key.sock, ua_sess);
 	}
-
 	ret = hashtable_destroy(app->sessions);
-	if (ret < 0) {
-		ERR("UST app destroy session hashtable failed");
-		goto end;
-	}
+	assert(!ret);
 
 	/*
 	 * Wait until we have removed the key from the sock hash table
@@ -229,7 +233,8 @@ end:
 /*
  * URCU intermediate call to delete an UST app.
  */
-static void delete_ust_app_rcu(struct rcu_head *head)
+static
+void delete_ust_app_rcu(struct rcu_head *head)
 {
 	struct cds_lfht_node *node =
 		caa_container_of(head, struct cds_lfht_node, head);
@@ -239,11 +244,137 @@ static void delete_ust_app_rcu(struct rcu_head *head)
 	delete_ust_app(app);
 }
 
+/*
+ * Alloc new UST app session.
+ */
+static
+struct ust_app_session *alloc_ust_app_session(void)
+{
+	struct ust_app_session *ua_sess;
+
+	/* Init most of the default value by allocating and zeroing */
+	ua_sess = zmalloc(sizeof(struct ust_app_session));
+	if (ua_sess == NULL) {
+		PERROR("malloc");
+		goto error;
+	}
+
+	ua_sess->handle = -1;
+	ua_sess->channels = hashtable_new_str(0);
+
+	return ua_sess;
+
+error:
+	return NULL;
+}
+
+/*
+ * Alloc new UST app channel.
+ */
+static
+struct ust_app_channel *alloc_ust_app_channel(char *name,
+		struct lttng_ust_channel *attr)
+{
+	struct ust_app_channel *ua_chan;
+
+	/* Init most of the default value by allocating and zeroing */
+	ua_chan = zmalloc(sizeof(struct ust_app_channel));
+	if (ua_chan == NULL) {
+		PERROR("malloc");
+		goto error;
+	}
+
+	/* Setup channel name */
+	strncpy(ua_chan->name, name, sizeof(ua_chan->name));
+	ua_chan->name[sizeof(ua_chan->name) - 1] = '\0';
+
+	ua_chan->enabled = 1;
+	ua_chan->handle = -1;
+	ua_chan->ctx = hashtable_new(0);
+	ua_chan->events = hashtable_new_str(0);
+	hashtable_node_init(&ua_chan->node, (void *) ua_chan->name,
+			strlen(ua_chan->name));
+
+	CDS_INIT_LIST_HEAD(&ua_chan->streams.head);
+
+	/* Copy attributes */
+	if (attr) {
+		memcpy(&ua_chan->attr, attr, sizeof(ua_chan->attr));
+	}
+
+	DBG3("UST app channel %s allocated", ua_chan->name);
+
+	return ua_chan;
+
+error:
+	return NULL;
+}
+
+/*
+ * Alloc new UST app event.
+ */
+static
+struct ust_app_event *alloc_ust_app_event(char *name,
+		struct lttng_ust_event *attr)
+{
+	struct ust_app_event *ua_event;
+
+	/* Init most of the default value by allocating and zeroing */
+	ua_event = zmalloc(sizeof(struct ust_app_event));
+	if (ua_event == NULL) {
+		PERROR("malloc");
+		goto error;
+	}
+
+	ua_event->enabled = 1;
+	strncpy(ua_event->name, name, sizeof(ua_event->name));
+	ua_event->name[sizeof(ua_event->name) - 1] = '\0';
+	ua_event->ctx = hashtable_new(0);
+	hashtable_node_init(&ua_event->node, (void *) ua_event->name,
+			strlen(ua_event->name));
+
+	/* Copy attributes */
+	if (attr) {
+		memcpy(&ua_event->attr, attr, sizeof(ua_event->attr));
+	}
+
+	DBG3("UST app event %s allocated", ua_event->name);
+
+	return ua_event;
+
+error:
+	return NULL;
+}
+
+/*
+ * Alloc new UST app context.
+ */
+static
+struct ust_app_ctx *alloc_ust_app_ctx(struct lttng_ust_context *uctx)
+{
+	struct ust_app_ctx *ua_ctx;
+
+	ua_ctx = zmalloc(sizeof(struct ust_app_ctx));
+	if (ua_ctx == NULL) {
+		goto error;
+	}
+
+	if (uctx) {
+		memcpy(&ua_ctx->ctx, uctx, sizeof(ua_ctx->ctx));
+	}
+
+	DBG3("UST app context %d allocated", ua_ctx->ctx.ctx);
+
+error:
+	return ua_ctx;
+}
+
 /*
  * Find an ust_app using the sock and return it. RCU read side lock must be
  * held before calling this helper function.
  */
-static struct ust_app *find_app_by_sock(int sock)
+static
+struct ust_app *find_app_by_sock(int sock)
 {
 	struct cds_lfht_node *node;
 	struct ust_app_key *key;
@@ -437,6 +568,8 @@ static int open_ust_metadata(struct ust_app *app,
 		goto error;
 	}
 
+	ua_sess->metadata->handle = ua_sess->metadata->obj->handle;
+
 error:
 	return ret;
 }
@@ -534,128 +667,6 @@ error:
 	return ret;
 }
 
-/*
- * Alloc new UST app session.
- */
-static struct ust_app_session *alloc_ust_app_session(void)
-{
-	struct ust_app_session *ua_sess;
-
-	/* Init most of the default value by allocating and zeroing */
-	ua_sess = zmalloc(sizeof(struct ust_app_session));
-	if (ua_sess == NULL) {
-		PERROR("malloc");
-		goto error;
-	}
-
-	ua_sess->handle = -1;
-	ua_sess->channels = hashtable_new_str(0);
-
-	return ua_sess;
-
-error:
-	return NULL;
-}
-
-/*
- * Alloc new UST app channel.
- */
-static struct ust_app_channel *alloc_ust_app_channel(char *name,
-		struct lttng_ust_channel *attr)
-{
-	struct ust_app_channel *ua_chan;
-
-	/* Init most of the default value by allocating and zeroing */
-	ua_chan = zmalloc(sizeof(struct ust_app_channel));
-	if (ua_chan == NULL) {
-		PERROR("malloc");
-		goto error;
-	}
-
-	/* Setup channel name */
-	strncpy(ua_chan->name, name, sizeof(ua_chan->name));
-	ua_chan->name[sizeof(ua_chan->name) - 1] = '\0';
-
-	ua_chan->enabled = 1;
-	ua_chan->handle = -1;
-	ua_chan->ctx = hashtable_new(0);
-	ua_chan->events = hashtable_new_str(0);
-	hashtable_node_init(&ua_chan->node, (void *) ua_chan->name,
-			strlen(ua_chan->name));
-
-	CDS_INIT_LIST_HEAD(&ua_chan->streams.head);
-
-	/* Copy attributes */
-	if (attr) {
-		memcpy(&ua_chan->attr, attr, sizeof(ua_chan->attr));
-	}
-
-	DBG3("UST app channel %s allocated", ua_chan->name);
-
-	return ua_chan;
-
-error:
-	return NULL;
-}
-
-/*
- * Alloc new UST app event.
- */
-static struct ust_app_event *alloc_ust_app_event(char *name,
-		struct lttng_ust_event *attr)
-{
-	struct ust_app_event *ua_event;
-
-	/* Init most of the default value by allocating and zeroing */
-	ua_event = zmalloc(sizeof(struct ust_app_event));
-	if (ua_event == NULL) {
-		PERROR("malloc");
-		goto error;
-	}
-
-	ua_event->enabled = 1;
-	strncpy(ua_event->name, name, sizeof(ua_event->name));
-	ua_event->name[sizeof(ua_event->name) - 1] = '\0';
-	ua_event->ctx = hashtable_new(0);
-	hashtable_node_init(&ua_event->node, (void *) ua_event->name,
-			strlen(ua_event->name));
-
-	/* Copy attributes */
-	if (attr) {
-		memcpy(&ua_event->attr, attr, sizeof(ua_event->attr));
-	}
-
-	DBG3("UST app event %s allocated", ua_event->name);
-
-	return ua_event;
-
-error:
-	return NULL;
-}
-
-/*
- * Alloc new UST app context.
- */
-static
-struct ust_app_ctx *alloc_ust_app_ctx(struct lttng_ust_context *uctx)
-{
-	struct ust_app_ctx *ua_ctx;
-
-	ua_ctx = zmalloc(sizeof(struct ust_app_ctx));
-	if (ua_ctx == NULL) {
-		goto error;
-	}
-
-	if (uctx) {
-		memcpy(&ua_ctx->ctx, uctx, sizeof(ua_ctx->ctx));
-	}
-
-	DBG3("UST app context %d allocated", ua_ctx->ctx.ctx);
-
-error:
-	return ua_ctx;
-}
-
 /*
  * Copy data between an UST app event and a LTT event.
  */
@@ -758,7 +769,9 @@ static void shadow_copy_session(struct ust_app_session *ua_sess,
 
 	DBG2("Shadow copy of session handle %d", ua_sess->handle);
 
+	ua_sess->id = usess->id;
 	ua_sess->uid = usess->uid;
+	ua_sess->gid = usess->gid;
 
 	ret = snprintf(ua_sess->path, PATH_MAX,
 			"%s/%s-%d-%s",
@@ -806,13 +819,13 @@ void __lookup_session_by_app(struct ltt_ust_session *usess,
 {
 	/* Get right UST app session from app */
 	(void) hashtable_lookup(app->sessions,
-			(void *) ((unsigned long) usess->uid), sizeof(void *),
+			(void *) ((unsigned long) usess->id), sizeof(void *),
 			iter);
 }
 
 /*
  * Return ust app session from the app session hashtable using the UST session
- * uid.
+ * id.
  */
 static struct ust_app_session *lookup_session_by_app(
 		struct ltt_ust_session *usess, struct ust_app *app)
@@ -846,8 +859,8 @@ static struct ust_app_session *create_ust_app_session(
 
 	ua_sess = lookup_session_by_app(usess, app);
 	if (ua_sess == NULL) {
-		DBG2("UST app pid: %d session uid %d not found, creating it",
-				app->key.pid, usess->uid);
+		DBG2("UST app pid: %d session id %d not found, creating it",
+				app->key.pid, usess->id);
 		ua_sess = alloc_ust_app_session();
 		if (ua_sess == NULL) {
 			/* Only malloc can failed so something is really wrong */
@@ -870,7 +883,7 @@ static struct ust_app_session *create_ust_app_session(
 
 		/* Add ust app session to app's HT */
 		hashtable_node_init(&ua_sess->node,
-				(void *)((unsigned long) ua_sess->uid), sizeof(void *));
+				(void *)((unsigned long) ua_sess->id), sizeof(void *));
 		hashtable_add_unique(app->sessions, &ua_sess->node);
 
 		DBG2("UST app session created successfully with handle %d", ret);
@@ -990,8 +1003,7 @@ error:
  * Disable on the tracer side a ust app event for the session and channel.
  */
 static int disable_ust_app_event(struct ust_app_session *ua_sess,
-		struct ust_app_channel *ua_chan, struct ust_app_event *ua_event,
-		struct ust_app *app)
+		struct ust_app_event *ua_event, struct ust_app *app)
 {
 	int ret;
 
@@ -1040,8 +1052,8 @@ static int enable_ust_app_channel(struct ust_app_session *ua_sess,
 	ua_chan_node = hashtable_lookup(ua_sess->channels,
 			(void *)uchan->name, strlen(uchan->name), &iter);
 	if (ua_chan_node == NULL) {
-		DBG2("Unable to find channel %s in ust session uid %u",
-				uchan->name, ua_sess->uid);
+		DBG2("Unable to find channel %s in ust session id %u",
+				uchan->name, ua_sess->id);
 		goto error;
 	}
 
@@ -1072,8 +1084,8 @@ static struct ust_app_channel *create_ust_app_channel(
 	ua_chan_node = hashtable_lookup(ua_sess->channels,
 			(void *)uchan->name, strlen(uchan->name), &iter);
 	if (ua_chan_node == NULL) {
-		DBG2("Unable to find channel %s in ust session uid %u",
-				uchan->name, ua_sess->uid);
+		DBG2("Unable to find channel %s in ust session id %u",
+				uchan->name, ua_sess->id);
 		ua_chan = alloc_ust_app_channel(uchan->name, &uchan->attr);
 		if (ua_chan == NULL) {
 			goto error;
@@ -1130,7 +1142,9 @@ int create_ust_app_event(struct ust_app_session *ua_sess,
 	/* Create it on the tracer side */
 	ret = create_ust_event(app, ua_sess, ua_chan, ua_event);
 	if (ret < 0) {
+		rcu_read_lock();
 		delete_ust_app_event(app->key.sock, ua_event);
+		rcu_read_unlock();
 		goto error;
 	}
 
@@ -1138,6 +1152,9 @@ int create_ust_app_event(struct ust_app_session *ua_sess,
 
 	hashtable_add_unique(ua_chan->events, &ua_event->node);
 
+	DBG2("UST app create event %s for PID %d completed",
+			ua_event->name, app->key.pid);
+
 end:
 error:
 	return ret;
@@ -1150,6 +1167,7 @@ static int create_ust_app_metadata(struct ust_app_session *ua_sess,
 		char *pathname, struct ust_app *app)
 {
 	int ret = 0;
+	mode_t old_umask;
 
 	if (ua_sess->metadata == NULL) {
 		/* Allocate UST metadata */
@@ -1175,11 +1193,18 @@ static int create_ust_app_metadata(struct ust_app_session *ua_sess,
 			goto error;
 		}
 
+		old_umask = umask(0);
 		ret = mkdir(ua_sess->path, S_IRWXU | S_IRWXG);
 		if (ret < 0) {
 			PERROR("mkdir UST metadata");
 			goto error;
 		}
+		ret = chown(ua_sess->path, ua_sess->uid, ua_sess->gid);
+		if (ret < 0) {
+			ERR("Unable to change owner of %s", ua_sess->path);
+			perror("chown");
+		}
+		umask(old_umask);
 
 		ret = snprintf(ua_sess->metadata->pathname, PATH_MAX,
 				"%s/metadata", ua_sess->path);
@@ -1364,6 +1389,8 @@ int ust_app_list_events(struct lttng_event **events)
 	rcu_read_lock();
 
 	cds_lfht_for_each_entry(ust_app_ht, &iter, app, node) {
+		struct lttng_ust_tracepoint_iter uiter;
+
 		handle = ustctl_tracepoint_list(app->key.sock);
 		if (handle < 0) {
 			ERR("UST app list events getting handle failed for app pid %d",
@@ -1372,11 +1399,11 @@ int ust_app_list_events(struct lttng_event **events)
 		}
 
 		while ((ret = ustctl_tracepoint_list_get(app->key.sock, handle,
-						tmp[count].name)) != -ENOENT) {
-			if (count > nbmem) {
-				DBG2("Reallocating event list from %zu to %zu bytes", nbmem,
-						nbmem + UST_APP_EVENT_LIST_SIZE);
-				nbmem += UST_APP_EVENT_LIST_SIZE;
+						&uiter)) != -ENOENT) {
+			if (count >= nbmem) {
+				DBG2("Reallocating event list from %zu to %zu entries", nbmem,
+						2 * nbmem);
+				nbmem *= 2;
 				tmp = realloc(tmp, nbmem * sizeof(struct lttng_event));
 				if (tmp == NULL) {
 					PERROR("realloc ust app events");
@@ -1384,7 +1411,9 @@ int ust_app_list_events(struct lttng_event **events)
 					goto rcu_error;
 				}
 			}
-
+			memcpy(tmp[count].name, uiter.name, LTTNG_UST_SYM_NAME_LEN);
+			memcpy(tmp[count].loglevel, uiter.loglevel, LTTNG_UST_SYM_NAME_LEN);
+			tmp[count].loglevel_value = uiter.loglevel_value;
 			tmp[count].type = LTTNG_UST_TRACEPOINT;
 			tmp[count].pid = app->key.pid;
 			tmp[count].enabled = -1;
@@ -1456,13 +1485,15 @@ int ust_app_disable_channel_glb(struct ltt_ust_session *usess,
 		goto error;
 	}
 
-	DBG2("UST app disabling channel %s from global domain for session uid %d",
-			uchan->name, usess->uid);
+	DBG2("UST app disabling channel %s from global domain for session id %d",
+			uchan->name, usess->id);
 
 	rcu_read_lock();
 
 	/* For every registered applications */
 	cds_lfht_for_each_entry(ust_app_ht, &iter, app, node) {
+		struct cds_lfht_iter uiter;
+
 		ua_sess = lookup_session_by_app(usess, app);
 		if (ua_sess == NULL) {
 			continue;
@@ -1470,7 +1501,7 @@ int ust_app_disable_channel_glb(struct ltt_ust_session *usess,
 
 		/* Get channel */
 		ua_chan_node = hashtable_lookup(ua_sess->channels,
-				(void *)uchan->name, strlen(uchan->name), &iter);
+				(void *)uchan->name, strlen(uchan->name), &uiter);
 		/* If the session if found for the app, the channel must be there */
 		assert(ua_chan_node);
 
@@ -1509,8 +1540,8 @@ int ust_app_enable_channel_glb(struct ltt_ust_session *usess,
 		goto error;
 	}
 
-	DBG2("UST app enabling channel %s to global domain for session uid %d",
-			uchan->name, usess->uid);
+	DBG2("UST app enabling channel %s to global domain for session id %d",
+			uchan->name, usess->id);
 
 	rcu_read_lock();
 
@@ -1542,7 +1573,7 @@ int ust_app_disable_event_glb(struct ltt_ust_session *usess,
 		struct ltt_ust_channel *uchan, struct ltt_ust_event *uevent)
 {
 	int ret = 0;
-	struct cds_lfht_iter iter, uiter;
+	struct cds_lfht_iter iter;
 	struct cds_lfht_node *ua_chan_node, *ua_event_node;
 	struct ust_app *app;
 	struct ust_app_session *ua_sess;
@@ -1550,12 +1581,14 @@ int ust_app_disable_event_glb(struct ltt_ust_session *usess,
 	struct ust_app_event *ua_event;
 
 	DBG("UST app disabling event %s for all apps in channel "
-			"%s for session uid %d", uevent->attr.name, uchan->name, usess->uid);
+			"%s for session id %d", uevent->attr.name, uchan->name, usess->id);
 
 	rcu_read_lock();
 
 	/* For all registered applications */
 	cds_lfht_for_each_entry(ust_app_ht, &iter, app, node) {
+		struct cds_lfht_iter uiter;
+
 		ua_sess = lookup_session_by_app(usess, app);
 		if (ua_sess == NULL) {
 			/* Next app */
@@ -1566,8 +1599,8 @@ int ust_app_disable_event_glb(struct ltt_ust_session *usess,
 		ua_chan_node = hashtable_lookup(ua_sess->channels,
 				(void *)uchan->name, strlen(uchan->name), &uiter);
 		if (ua_chan_node == NULL) {
-			DBG2("Channel %s not found in session uid %d for app pid %d."
-					"Skipping", uchan->name, usess->uid, app->key.pid);
+			DBG2("Channel %s not found in session id %d for app pid %d."
+					"Skipping", uchan->name, usess->id, app->key.pid);
 			continue;
 		}
 		ua_chan = caa_container_of(ua_chan_node, struct ust_app_channel, node);
@@ -1581,7 +1614,7 @@ int ust_app_disable_event_glb(struct ltt_ust_session *usess,
 		}
 		ua_event = caa_container_of(ua_event_node, struct ust_app_event, node);
 
-		ret = disable_ust_app_event(ua_sess, ua_chan, ua_event, app);
+		ret = disable_ust_app_event(ua_sess, ua_event, app);
 		if (ret < 0) {
 			/* XXX: Report error someday... */
 			continue;
@@ -1601,7 +1634,7 @@ int ust_app_disable_all_event_glb(struct ltt_ust_session *usess,
 		struct ltt_ust_channel *uchan)
 {
 	int ret = 0;
-	struct cds_lfht_iter iter, uiter;
+	struct cds_lfht_iter iter;
 	struct cds_lfht_node *ua_chan_node;
 	struct ust_app *app;
 	struct ust_app_session *ua_sess;
@@ -1609,12 +1642,14 @@ int ust_app_disable_all_event_glb(struct ltt_ust_session *usess,
 	struct ust_app_event *ua_event;
 
 	DBG("UST app disabling all event for all apps in channel "
-			"%s for session uid %d", uchan->name, usess->uid);
+			"%s for session id %d", uchan->name, usess->id);
 
 	rcu_read_lock();
 
 	/* For all registered applications */
 	cds_lfht_for_each_entry(ust_app_ht, &iter, app, node) {
+		struct cds_lfht_iter uiter;
+
 		ua_sess = lookup_session_by_app(usess, app);
 		/* If ua_sess is NULL, there is a code flow error */
 		assert(ua_sess);
@@ -1629,7 +1664,7 @@ int ust_app_disable_all_event_glb(struct ltt_ust_session *usess,
 
 		/* Disable each events of channel */
 		cds_lfht_for_each_entry(ua_chan->events, &uiter, ua_event, node) {
-			ret = disable_ust_app_event(ua_sess, ua_chan, ua_event, app);
+			ret = disable_ust_app_event(ua_sess, ua_event, app);
 			if (ret < 0) {
 				/* XXX: Report error someday... */
 				continue;
@@ -1660,8 +1695,8 @@ int ust_app_create_channel_glb(struct ltt_ust_session *usess,
 		goto error;
 	}
 
-	DBG2("UST app adding channel %s to global domain for session uid %d",
-			uchan->name, usess->uid);
+	DBG2("UST app adding channel %s to global domain for session id %d",
+			uchan->name, usess->id);
 
 	rcu_read_lock();
 
@@ -1697,15 +1732,15 @@ int ust_app_enable_event_glb(struct ltt_ust_session *usess,
 		struct ltt_ust_channel *uchan, struct ltt_ust_event *uevent)
 {
 	int ret = 0;
-	struct cds_lfht_iter iter, uiter;
+	struct cds_lfht_iter iter;
 	struct cds_lfht_node *ua_chan_node, *ua_event_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 enabling event %s for all apps for session uid %d",
-			uevent->attr.name, usess->uid);
+	DBG("UST app enabling event %s for all apps for session id %d",
+			uevent->attr.name, usess->id);
 
 	/*
 	 * NOTE: At this point, this function is called only if the session and
@@ -1717,6 +1752,8 @@ int ust_app_enable_event_glb(struct ltt_ust_session *usess,
 
 	/* For all registered applications */
 	cds_lfht_for_each_entry(ust_app_ht, &iter, app, node) {
+		struct cds_lfht_iter uiter;
+
 		ua_sess = lookup_session_by_app(usess, app);
 		/* If ua_sess is NULL, there is a code flow error */
 		assert(ua_sess);
@@ -1729,24 +1766,23 @@ int ust_app_enable_event_glb(struct ltt_ust_session *usess,
 
 		ua_chan = caa_container_of(ua_chan_node, struct ust_app_channel, node);
 
-		ua_event_node = hashtable_lookup(ua_sess->channels,
+		ua_event_node = hashtable_lookup(ua_chan->events,
 				(void*)uevent->attr.name, strlen(uevent->attr.name), &uiter);
 		if (ua_event_node == NULL) {
-			DBG3("UST app enable event %s not found. Skipping app",
-					uevent->attr.name);
+			DBG3("UST app enable event %s not found for app PID %d."
+					"Skipping app", uevent->attr.name, app->key.pid);
 			continue;
 		}
 		ua_event = caa_container_of(ua_event_node, struct ust_app_event, node);
 
 		ret = enable_ust_app_event(ua_sess, ua_event, app);
 		if (ret < 0) {
-			/* XXX: Report error someday... */
-			continue;
+			goto error;
 		}
 	}
 
+error:
 	rcu_read_unlock();
-
 	return ret;
 }
 
@@ -1758,14 +1794,14 @@ int ust_app_create_event_glb(struct ltt_ust_session *usess,
 		struct ltt_ust_channel *uchan, struct ltt_ust_event *uevent)
 {
 	int ret = 0;
-	struct cds_lfht_iter iter, uiter;
+	struct cds_lfht_iter iter;
 	struct cds_lfht_node *ua_chan_node;
 	struct ust_app *app;
 	struct ust_app_session *ua_sess;
 	struct ust_app_channel *ua_chan;
 
-	DBG("UST app creating event %s for all apps for session uid %d",
-			uevent->attr.name, usess->uid);
+	DBG("UST app creating event %s for all apps for session id %d",
+			uevent->attr.name, usess->id);
 
 	/*
 	 * NOTE: At this point, this function is called only if the session and
@@ -1777,6 +1813,8 @@ int ust_app_create_event_glb(struct ltt_ust_session *usess,
 
 	/* For all registered applications */
 	cds_lfht_for_each_entry(ust_app_ht, &iter, app, node) {
+		struct cds_lfht_iter uiter;
+
 		ua_sess = lookup_session_by_app(usess, app);
 		/* If ua_sess is NULL, there is a code flow error */
 		assert(ua_sess);
@@ -1909,7 +1947,9 @@ error_rcu_unlock:
 int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app)
 {
 	int ret = 0;
+	struct cds_lfht_iter iter;
 	struct ust_app_session *ua_sess;
+	struct ust_app_channel *ua_chan;
 
 	DBG("Stopping tracing for ust app pid %d", app->key.pid);
 
@@ -1921,34 +1961,37 @@ int ust_app_stop_trace(struct ltt_ust_session *usess, struct ust_app *app)
 		goto error_rcu_unlock;
 	}
 
-#if 0	/* only useful when periodical flush will be supported */
-	/* need to keep a handle on shm in session for this. */
-	/* Flush all buffers before stopping */
-	ret = ustctl_flush_buffer(usess->sock, usess->metadata->obj);
+	/* This inhibits UST tracing */
+	ret = ustctl_stop_session(app->key.sock, ua_sess->handle);
 	if (ret < 0) {
-		ERR("UST metadata flush failed");
+		ERR("Error stopping tracing for app pid: %d", app->key.pid);
+		goto error_rcu_unlock;
 	}
 
-	cds_list_for_each_entry(ustchan, &usess->channels.head, list) {
-		ret = ustctl_flush_buffer(usess->sock, ustchan->obj);
+	/* Quiescent wait after stopping trace */
+	ustctl_wait_quiescent(app->key.sock);
+
+	/* Flushing buffers */
+	cds_lfht_for_each_entry(ua_sess->channels, &iter, ua_chan, node) {
+		ret = ustctl_sock_flush_buffer(app->key.sock, ua_chan->obj);
 		if (ret < 0) {
-			ERR("UST flush buffer error");
+			ERR("UST app PID %d channel %s flush failed",
+					app->key.pid, ua_chan->name);
+			ERR("Ended with ret %d", ret);
+			/* Continuing flushing all buffers */
+			continue;
 		}
 	}
-#endif
 
-	/* This inhibits UST tracing */
-	ret = ustctl_stop_session(app->key.sock, ua_sess->handle);
+	/* Flush all buffers before stopping */
+	ret = ustctl_sock_flush_buffer(app->key.sock, ua_sess->metadata->obj);
 	if (ret < 0) {
-		ERR("Error stopping tracing for app pid: %d", app->key.pid);
-		goto error_rcu_unlock;
+		ERR("UST app PID %d metadata flush failed", app->key.pid);
+		ERR("Ended with ret %d", ret);
 	}
 
 	rcu_read_unlock();
 
-	/* Quiescent wait after stopping trace */
-	ustctl_wait_quiescent(app->key.sock);
-
 	return 0;
 
 error_rcu_unlock:
@@ -2094,8 +2137,8 @@ void ust_app_global_update(struct ltt_ust_session *usess, int sock)
 		goto error;
 	}
 
-	DBG2("UST app global update for app sock %d for session uid %d", sock,
-			usess->uid);
+	DBG2("UST app global update for app sock %d for session id %d", sock,
+			usess->id);
 
 	rcu_read_lock();
 
@@ -2116,6 +2159,8 @@ void ust_app_global_update(struct ltt_ust_session *usess, int sock)
 	 * ltt ust session.
 	 */
 	cds_lfht_for_each_entry(ua_sess->channels, &iter, ua_chan, node) {
+		struct cds_lfht_iter uiter;
+
 		ret = create_ust_channel(app, ua_sess, ua_chan);
 		if (ret < 0) {
 			/* FIXME: Should we quit here or continue... */
@@ -2123,7 +2168,7 @@ void ust_app_global_update(struct ltt_ust_session *usess, int sock)
 		}
 
 		/* For each events */
-		cds_lfht_for_each_entry(ua_chan->events, &iter, ua_event, node) {
+		cds_lfht_for_each_entry(ua_chan->events, &uiter, ua_event, node) {
 			ret = create_ust_event(app, ua_sess, ua_chan, ua_event);
 			if (ret < 0) {
 				/* FIXME: Should we quit here or continue... */
@@ -2154,7 +2199,7 @@ int ust_app_add_ctx_channel_glb(struct ltt_ust_session *usess,
 {
 	int ret = 0;
 	struct cds_lfht_node *ua_chan_node;
-	struct cds_lfht_iter iter, uiter;
+	struct cds_lfht_iter iter;
 	struct ust_app_channel *ua_chan = NULL;
 	struct ust_app_session *ua_sess;
 	struct ust_app *app;
@@ -2162,6 +2207,8 @@ int ust_app_add_ctx_channel_glb(struct ltt_ust_session *usess,
 	rcu_read_lock();
 
 	cds_lfht_for_each_entry(ust_app_ht, &iter, app, node) {
+		struct cds_lfht_iter uiter;
+
 		ua_sess = lookup_session_by_app(usess, app);
 		if (ua_sess == NULL) {
 			continue;
@@ -2182,9 +2229,6 @@ int ust_app_add_ctx_channel_glb(struct ltt_ust_session *usess,
 		}
 	}
 
-	/* Add ltt UST context node to ltt UST channel */
-	hashtable_add_unique(uchan->ctx, &uctx->node);
-
 	rcu_read_unlock();
 	return ret;
 }
@@ -2198,7 +2242,7 @@ int ust_app_add_ctx_event_glb(struct ltt_ust_session *usess,
 {
 	int ret = 0;
 	struct cds_lfht_node *ua_chan_node, *ua_event_node;
-	struct cds_lfht_iter iter, uiter;
+	struct cds_lfht_iter iter;
 	struct ust_app_session *ua_sess;
 	struct ust_app_event *ua_event;
 	struct ust_app_channel *ua_chan = NULL;
@@ -2207,6 +2251,8 @@ int ust_app_add_ctx_event_glb(struct ltt_ust_session *usess,
 	rcu_read_lock();
 
 	cds_lfht_for_each_entry(ust_app_ht, &iter, app, node) {
+		struct cds_lfht_iter uiter;
+
 		ua_sess = lookup_session_by_app(usess, app);
 		if (ua_sess == NULL) {
 			continue;
@@ -2235,9 +2281,120 @@ int ust_app_add_ctx_event_glb(struct ltt_ust_session *usess,
 		}
 	}
 
-	/* Add ltt UST context node to ltt UST event */
-	hashtable_add_unique(uevent->ctx, &uctx->node);
+	rcu_read_unlock();
+	return ret;
+}
+
+/*
+ * Enable event for a channel from a UST session for a specific PID.
+ */
+int ust_app_enable_event_pid(struct ltt_ust_session *usess,
+		struct ltt_ust_channel *uchan, struct ltt_ust_event *uevent, pid_t pid)
+{
+	int ret = 0;
+	struct cds_lfht_iter iter;
+	struct cds_lfht_node *ua_chan_node, *ua_event_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 enabling event %s for PID %d", uevent->attr.name, pid);
+
+	rcu_read_lock();
+
+	app = ust_app_find_by_pid(pid);
+	if (app == NULL) {
+		ERR("UST app enable event per PID %d not found", pid);
+		ret = -1;
+		goto error;
+	}
+
+	ua_sess = lookup_session_by_app(usess, app);
+	/* If ua_sess is NULL, there is a code flow error */
+	assert(ua_sess);
+
+	/* Lookup channel in the ust app session */
+	ua_chan_node = hashtable_lookup(ua_sess->channels, (void *)uchan->name,
+			strlen(uchan->name), &iter);
+	/* If the channel is not found, there is a code flow error */
+	assert(ua_chan_node);
+
+	ua_chan = caa_container_of(ua_chan_node, struct ust_app_channel, node);
+
+	ua_event_node = hashtable_lookup(ua_chan->events,
+			(void*)uevent->attr.name, strlen(uevent->attr.name), &iter);
+	if (ua_event_node == NULL) {
+		ret = create_ust_app_event(ua_sess, ua_chan, uevent, app);
+		if (ret < 0) {
+			goto error;
+		}
+	} else {
+		ua_event = caa_container_of(ua_event_node, struct ust_app_event, node);
+
+		ret = enable_ust_app_event(ua_sess, ua_event, app);
+		if (ret < 0) {
+			goto error;
+		}
+	}
+
+error:
+	rcu_read_unlock();
+	return ret;
+}
+
+/*
+ * Disable event for a channel from a UST session for a specific PID.
+ */
+int ust_app_disable_event_pid(struct ltt_ust_session *usess,
+		struct ltt_ust_channel *uchan, struct ltt_ust_event *uevent, pid_t pid)
+{
+	int ret = 0;
+	struct cds_lfht_iter iter;
+	struct cds_lfht_node *ua_chan_node, *ua_event_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 PID %d", uevent->attr.name, pid);
+
+	rcu_read_lock();
+
+	app = ust_app_find_by_pid(pid);
+	if (app == NULL) {
+		ERR("UST app disable event per PID %d not found", pid);
+		ret = -1;
+		goto error;
+	}
+
+	ua_sess = lookup_session_by_app(usess, app);
+	/* If ua_sess is NULL, there is a code flow error */
+	assert(ua_sess);
+
+	/* Lookup channel in the ust app session */
+	ua_chan_node = hashtable_lookup(ua_sess->channels, (void *)uchan->name,
+			strlen(uchan->name), &iter);
+	if (ua_chan_node == NULL) {
+		/* Channel does not exist, skip disabling */
+		goto error;
+	}
+	ua_chan = caa_container_of(ua_chan_node, struct ust_app_channel, node);
+
+	ua_event_node = hashtable_lookup(ua_chan->events,
+			(void*)uevent->attr.name, strlen(uevent->attr.name), &iter);
+	if (ua_event_node == NULL) {
+		/* Event does not exist, skip disabling */
+		goto error;
+	}
+	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) {
+		goto error;
+	}
+
+error:
 	rcu_read_unlock();
 	return ret;
 }