X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=plugins%2Fctf%2Flttng-live%2Flttng-live.c;h=9cc2f87938d61e0cc576dda0f79cab8ad9f3050c;hb=7cdc2bab17acd56d035b204518ef845fa5a9f1c7;hp=5f082fcc5ef0f4a49016052cd24797f7005f8adf;hpb=d3eb6e8fd59ebff26cb99a70d375e542d49575a3;p=babeltrace.git

diff --git a/plugins/ctf/lttng-live/lttng-live.c b/plugins/ctf/lttng-live/lttng-live.c
index 5f082fcc..9cc2f879 100644
--- a/plugins/ctf/lttng-live/lttng-live.c
+++ b/plugins/ctf/lttng-live/lttng-live.c
@@ -4,6 +4,7 @@
  * Babeltrace CTF LTTng-live Client Component
  *
  * Copyright 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
  * Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
  *
@@ -26,27 +27,1051 @@
  * SOFTWARE.
  */
 
-#include "lttng-live-internal.h"
-#include <babeltrace/component/component-source.h>
+#include <babeltrace/ctf-ir/packet.h>
+#include <babeltrace/graph/component-source.h>
+#include <babeltrace/graph/private-port.h>
+#include <babeltrace/graph/port.h>
+#include <babeltrace/graph/private-component.h>
+#include <babeltrace/graph/private-component-source.h>
+#include <babeltrace/graph/private-notification-iterator.h>
+#include <babeltrace/graph/notification-stream.h>
+#include <babeltrace/graph/notification-packet.h>
+#include <babeltrace/graph/notification-event.h>
+#include <babeltrace/graph/notification-heap.h>
+#include <babeltrace/graph/notification-iterator.h>
+#include <babeltrace/graph/notification-inactivity.h>
+#include <babeltrace/compiler-internal.h>
+#include <inttypes.h>
+#include <glib.h>
+#include <assert.h>
+#include <unistd.h>
 #include <plugins-common.h>
 
+#include "lttng-live-internal.h"
+#include "data-stream.h"
+#include "metadata.h"
+
+#define PRINT_ERR_STREAM	(lttng_live->error_fp)
+#define PRINT_PREFIX		"lttng-live"
+#define PRINT_DBG_CHECK		lttng_live_debug
+#define MAX_QUERY_SIZE		(256*1024)
+#include "../print.h"
+
+#ifdef LIVE_DEBUG
+#define print_dbg(fmt, args...)	\
+	fprintf(stderr, "%s() at " __FILE__ ":%d " fmt "\n",	\
+		__func__, __LINE__, ## args)
+
+static const char *print_state(struct lttng_live_stream_iterator *s)
+{
+	switch (s->state) {
+	case LTTNG_LIVE_STREAM_ACTIVE_NO_DATA:
+		return "ACTIVE_NO_DATA";
+	case LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA:
+		return "QUIESCENT_NO_DATA";
+	case LTTNG_LIVE_STREAM_QUIESCENT:
+		return "QUIESCENT";
+	case LTTNG_LIVE_STREAM_ACTIVE_DATA:
+		return "ACTIVE_DATA";
+	case LTTNG_LIVE_STREAM_EOF:
+		return "EOF";
+	default:
+		return "ERROR";
+	}
+}
+#else
+#define print_dbg(fmt, args...)
+#endif
+
+#define print_stream_state(stream)	\
+	print_dbg("stream %s state %s last_inact_ts %" PRId64 " cur_inact_ts %" PRId64,	\
+			bt_port_get_name(bt_port_from_private_port(stream->port)),	\
+			print_state(stream), stream->last_returned_inactivity_timestamp,	\
+			stream->current_inactivity_timestamp)
+
+BT_HIDDEN
+bool lttng_live_debug;
+
+BT_HIDDEN
+int lttng_live_add_port(struct lttng_live_component *lttng_live,
+		struct lttng_live_stream_iterator *stream_iter)
+{
+	int ret;
+	struct bt_private_port *private_port;
+	char name[STREAM_NAME_MAX_LEN];
+
+	ret = sprintf(name, STREAM_NAME_PREFIX "%" PRIu64, stream_iter->viewer_stream_id);
+	assert(ret > 0);
+	strcpy(stream_iter->name, name);
+	private_port = bt_private_component_source_add_output_private_port(
+			lttng_live->private_component, name, stream_iter);
+	if (!private_port) {
+		return -1;
+	}
+	PDBG("Added port %s\n", name);
+
+	if (lttng_live->no_stream_port) {
+		ret = bt_private_port_remove_from_component(lttng_live->no_stream_port);
+		if (ret) {
+			return -1;
+		}
+		BT_PUT(lttng_live->no_stream_port);
+		lttng_live->no_stream_iter->port = NULL;
+	}
+	stream_iter->port = private_port;
+	return 0;
+}
+
+BT_HIDDEN
+int lttng_live_remove_port(struct lttng_live_component *lttng_live,
+		struct bt_private_port *port)
+{
+	struct bt_component *component;
+	int64_t nr_ports;
+	int ret;
+
+	component = bt_component_from_private_component(lttng_live->private_component);
+	nr_ports = bt_component_source_get_output_port_count(component);
+	if (nr_ports < 0) {
+		return -1;
+	}
+	BT_PUT(component);
+	if (nr_ports == 1) {
+		assert(!lttng_live->no_stream_port);
+		lttng_live->no_stream_port =
+			bt_private_component_source_add_output_private_port(lttng_live->private_component,
+				"no-stream", lttng_live->no_stream_iter);
+		if (!lttng_live->no_stream_port) {
+			return -1;
+		}
+		lttng_live->no_stream_iter->port = lttng_live->no_stream_port;
+	}
+	ret = bt_private_port_remove_from_component(port);
+	if (ret) {
+		return -1;
+	}
+	return 0;
+}
+
+static
+struct lttng_live_trace *lttng_live_find_trace(struct lttng_live_session *session,
+		uint64_t trace_id)
+{
+	struct lttng_live_trace *trace;
+
+	bt_list_for_each_entry(trace, &session->traces, node) {
+		if (trace->id == trace_id) {
+			return trace;
+		}
+	}
+	return NULL;
+}
+
+static
+void lttng_live_destroy_trace(struct bt_object *obj)
+{
+	struct lttng_live_trace *trace = container_of(obj, struct lttng_live_trace, obj);
+
+	PDBG("Destroy trace\n");
+	assert(bt_list_empty(&trace->streams));
+	bt_list_del(&trace->node);
+	lttng_live_metadata_fini(trace);
+	BT_PUT(trace->cc_prio_map);
+	g_free(trace);
+}
+
+static
+struct lttng_live_trace *lttng_live_create_trace(struct lttng_live_session *session,
+		uint64_t trace_id)
+{
+	struct lttng_live_trace *trace = NULL;
+
+	trace = g_new0(struct lttng_live_trace, 1);
+	if (!trace) {
+		goto error;
+	}
+	trace->session = session;
+	trace->id = trace_id;
+	BT_INIT_LIST_HEAD(&trace->streams);
+	trace->new_metadata_needed = true;
+	bt_list_add(&trace->node, &session->traces);
+	bt_object_init(&trace->obj, lttng_live_destroy_trace);
+	goto end;
+error:
+	g_free(trace);
+	trace = NULL;
+end:
+	return trace;
+}
+
+BT_HIDDEN
+struct lttng_live_trace *lttng_live_ref_trace(struct lttng_live_session *session,
+		uint64_t trace_id)
+{
+	struct lttng_live_trace *trace;
+
+	trace = lttng_live_find_trace(session, trace_id);
+	if (trace) {
+		bt_get(trace);
+		return trace;
+	}
+	return lttng_live_create_trace(session, trace_id);
+}
+
+BT_HIDDEN
+void lttng_live_unref_trace(struct lttng_live_trace *trace)
+{
+	bt_put(trace);
+}
+
+static
+void lttng_live_close_trace_streams(struct lttng_live_trace *trace)
+{
+	struct lttng_live_stream_iterator *stream, *s;
+
+	bt_list_for_each_entry_safe(stream, s, &trace->streams, node) {
+		lttng_live_stream_iterator_destroy(stream);
+	}
+	lttng_live_metadata_fini(trace);
+}
+
+BT_HIDDEN
+int lttng_live_add_session(struct lttng_live_component *lttng_live, uint64_t session_id)
+{
+	int ret = 0;
+	struct lttng_live_session *s;
+
+	s = g_new0(struct lttng_live_session, 1);
+	if (!s) {
+		goto error;
+	}
+
+	s->id = session_id;
+	BT_INIT_LIST_HEAD(&s->traces);
+	s->lttng_live = lttng_live;
+	s->new_streams_needed = true;
+
+	PDBG("Reading from session %" PRIu64 "\n", s->id);
+	bt_list_add(&s->node, &lttng_live->sessions);
+	goto end;
+error:
+	PERR("Error adding session\n");
+	g_free(s);
+	ret = -1;
+end:
+	return ret;
+}
+
+static
+void lttng_live_destroy_session(struct lttng_live_session *session)
+{
+	struct lttng_live_trace *trace, *t;
+
+	PDBG("Destroy session\n");
+	if (session->id != -1ULL) {
+		if (lttng_live_detach_session(session)) {
+			/* Old relayd cannot detach sessions. */
+			PDBG("Unable to detach session %" PRIu64 "\n",
+				session->id);
+		}
+		session->id = -1ULL;
+	}
+	bt_list_for_each_entry_safe(trace, t, &session->traces, node) {
+		lttng_live_close_trace_streams(trace);
+	}
+	bt_list_del(&session->node);
+	g_free(session);
+}
+
+BT_HIDDEN
+void lttng_live_iterator_finalize(struct bt_private_notification_iterator *it)
+{
+	struct lttng_live_stream_iterator_generic *s =
+			bt_private_notification_iterator_get_user_data(it);
+
+	switch (s->type) {
+	case LIVE_STREAM_TYPE_NO_STREAM:
+	{
+		/* Leave no_stream_iter in place when port is removed. */
+		break;
+	}
+	case LIVE_STREAM_TYPE_STREAM:
+	{
+		struct lttng_live_stream_iterator *stream_iter =
+			container_of(s, struct lttng_live_stream_iterator, p);
+
+		lttng_live_stream_iterator_destroy(stream_iter);
+		break;
+	}
+	}
+}
+
+static
+enum bt_ctf_lttng_live_iterator_status lttng_live_iterator_next_check_stream_state(
+		struct lttng_live_component *lttng_live,
+		struct lttng_live_stream_iterator *lttng_live_stream)
+{
+	switch (lttng_live_stream->state) {
+	case LTTNG_LIVE_STREAM_QUIESCENT:
+	case LTTNG_LIVE_STREAM_ACTIVE_DATA:
+		break;
+	case LTTNG_LIVE_STREAM_ACTIVE_NO_DATA:
+		/* Invalid state. */
+		PERR("Unexpected stream state \"ACTIVE_NO_DATA\"\n");
+		return BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_ERROR;
+	case LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA:
+		/* Invalid state. */
+		PERR("Unexpected stream state \"QUIESCENT_NO_DATA\"\n");
+		return BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_ERROR;
+	case LTTNG_LIVE_STREAM_EOF:
+		break;
+	}
+	return BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK;
+}
+
+/*
+ * For active no data stream, fetch next data. It can be either:
+ * - quiescent: need to put it in the prio heap at quiescent end
+ *   timestamp,
+ * - have data: need to wire up first event into the prio heap,
+ * - have no data on this stream at this point: need to retry (AGAIN) or
+ *   return EOF.
+ */
+static
+enum bt_ctf_lttng_live_iterator_status lttng_live_iterator_next_handle_one_no_data_stream(
+		struct lttng_live_component *lttng_live,
+		struct lttng_live_stream_iterator *lttng_live_stream)
+{
+	enum bt_ctf_lttng_live_iterator_status ret =
+			BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK;
+	struct packet_index index;
+	enum lttng_live_stream_state orig_state = lttng_live_stream->state;
+
+	if (lttng_live_stream->trace->new_metadata_needed) {
+		ret = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
+		goto end;
+	}
+	if (lttng_live_stream->trace->session->new_streams_needed) {
+		ret = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
+		goto end;
+	}
+	if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_NO_DATA
+			&& lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA) {
+		goto end;
+	}
+	ret = lttng_live_get_next_index(lttng_live, lttng_live_stream, &index);
+	if (ret != BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK) {
+		goto end;
+	}
+	assert(lttng_live_stream->state != LTTNG_LIVE_STREAM_EOF);
+	if (lttng_live_stream->state == LTTNG_LIVE_STREAM_QUIESCENT) {
+		if (orig_state == LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA
+				&& lttng_live_stream->last_returned_inactivity_timestamp ==
+					lttng_live_stream->current_inactivity_timestamp) {
+			ret = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
+			print_stream_state(lttng_live_stream);
+		} else {
+			ret = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
+		}
+		goto end;
+	}
+	lttng_live_stream->base_offset = index.offset;
+	lttng_live_stream->offset = index.offset;
+	lttng_live_stream->len = index.packet_size / CHAR_BIT;
+end:
+	if (ret == BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK) {
+		ret = lttng_live_iterator_next_check_stream_state(
+				lttng_live, lttng_live_stream);
+	}
+	return ret;
+}
+
+/*
+ * Creation of the notification requires the ctf trace to be created
+ * beforehand, but the live protocol gives us all streams (including
+ * metadata) at once. So we split it in three steps: getting streams,
+ * getting metadata (which creates the ctf trace), and then creating the
+ * per-stream notifications.
+ */
+static
+enum bt_ctf_lttng_live_iterator_status lttng_live_get_session(
+		struct lttng_live_component *lttng_live,
+		struct lttng_live_session *session)
+{
+	enum bt_ctf_lttng_live_iterator_status status;
+	struct lttng_live_trace *trace, *t;
+
+	if (lttng_live_attach_session(session)) {
+		return BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_ERROR;
+	}
+	status = lttng_live_get_new_streams(session);
+	if (status != BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK &&
+			status != BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_END) {
+		return status;
+	}
+	bt_list_for_each_entry_safe(trace, t, &session->traces, node) {
+		status = lttng_live_metadata_update(trace);
+		if (status == BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_END) {
+			int retval;
+
+			retval = bt_ctf_trace_set_is_static(trace->trace);
+			assert(!retval);
+		} else if (status != BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK) {
+			return status;
+		}
+	}
+	return lttng_live_lazy_notif_init(session);
+}
+
+BT_HIDDEN
+void lttng_live_need_new_streams(struct lttng_live_component *lttng_live)
+{
+	struct lttng_live_session *session;
+
+	bt_list_for_each_entry(session, &lttng_live->sessions, node) {
+		session->new_streams_needed = true;
+	}
+}
+
+static
+void lttng_live_force_new_streams_and_metadata(struct lttng_live_component *lttng_live)
+{
+	struct lttng_live_session *session;
+
+	bt_list_for_each_entry(session, &lttng_live->sessions, node) {
+		struct lttng_live_trace *trace;
+
+		session->new_streams_needed = true;
+		bt_list_for_each_entry(trace, &session->traces, node) {
+			trace->new_metadata_needed = true;
+		}
+	}
+}
+
+static
+enum bt_notification_iterator_status lttng_live_iterator_next_handle_new_streams_and_metadata(
+		struct lttng_live_component *lttng_live)
+{
+	enum bt_ctf_lttng_live_iterator_status ret =
+			BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK;
+	unsigned int nr_sessions_opened = 0;
+	struct lttng_live_session *session, *s;
+
+	bt_list_for_each_entry_safe(session, s, &lttng_live->sessions, node) {
+		if (session->closed && bt_list_empty(&session->traces)) {
+			lttng_live_destroy_session(session);
+		}
+	}
+	/*
+	 * Currently, when there are no sessions, we quit immediately.
+	 * We may want to add a component parameter to keep trying until
+	 * we get data in the future.
+	 * Also, in a remotely distant future, we could add a "new
+	 * session" flag to the protocol, which would tell us that we
+	 * need to query for new sessions even though we have sessions
+	 * currently ongoing.
+	 */
+	if (bt_list_empty(&lttng_live->sessions)) {
+		ret = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_END;
+		goto end;
+	}
+	bt_list_for_each_entry(session, &lttng_live->sessions, node) {
+		ret = lttng_live_get_session(lttng_live, session);
+		switch (ret) {
+		case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK:
+			break;
+		case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_END:
+			ret = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK;
+			break;
+		default:
+			goto end;
+		}
+		if (!session->closed) {
+			nr_sessions_opened++;
+		}
+	}
+end:
+	if (ret == BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK && !nr_sessions_opened) {
+		ret = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_END;
+	}
+	return ret;
+}
+
+static
+enum bt_ctf_lttng_live_iterator_status emit_inactivity_notification(
+		struct lttng_live_component *lttng_live,
+		struct lttng_live_stream_iterator *lttng_live_stream,
+		struct bt_notification **notification,
+		uint64_t timestamp)
+{
+	enum bt_ctf_lttng_live_iterator_status ret =
+			BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK;
+	struct lttng_live_trace *trace;
+	struct bt_ctf_clock_class *clock_class = NULL;
+	struct bt_ctf_clock_value *clock_value = NULL;
+	struct bt_notification *notif = NULL;
+	int retval;
+
+	trace = lttng_live_stream->trace;
+	if (!trace) {
+		goto error;
+	}
+	clock_class = bt_clock_class_priority_map_get_clock_class_by_index(trace->cc_prio_map, 0);
+	if (!clock_class) {
+		goto error;
+	}
+	clock_value = bt_ctf_clock_value_create(clock_class, timestamp);
+	if (!clock_value) {
+		goto error;
+	}
+	notif = bt_notification_inactivity_create(trace->cc_prio_map);
+	if (!notif) {
+		goto error;
+	}
+	retval = bt_notification_inactivity_set_clock_value(notif, clock_value);
+	if (retval) {
+		goto error;
+	}
+	*notification = notif;
+end:
+	bt_put(clock_value);
+	bt_put(clock_class);
+	return ret;
+
+error:
+	ret = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_ERROR;
+	bt_put(notif);
+	goto end;
+}
+
+static
+enum bt_ctf_lttng_live_iterator_status lttng_live_iterator_next_handle_one_quiescent_stream(
+		struct lttng_live_component *lttng_live,
+		struct lttng_live_stream_iterator *lttng_live_stream,
+		struct bt_notification **notification)
+{
+	enum bt_ctf_lttng_live_iterator_status ret =
+			BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK;
+	struct bt_ctf_clock_class *clock_class = NULL;
+	struct bt_ctf_clock_value *clock_value = NULL;
+
+	if (lttng_live_stream->state != LTTNG_LIVE_STREAM_QUIESCENT) {
+		return BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK;
+	}
+
+	if (lttng_live_stream->current_inactivity_timestamp ==
+			lttng_live_stream->last_returned_inactivity_timestamp) {
+		lttng_live_stream->state = LTTNG_LIVE_STREAM_QUIESCENT_NO_DATA;
+		ret = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
+		goto end;
+	}
+
+	ret = emit_inactivity_notification(lttng_live, lttng_live_stream, notification,
+			(uint64_t) lttng_live_stream->current_inactivity_timestamp);
+
+	lttng_live_stream->last_returned_inactivity_timestamp =
+			lttng_live_stream->current_inactivity_timestamp;
+end:
+	bt_put(clock_value);
+	bt_put(clock_class);
+	return ret;
+}
+
+static
+enum bt_ctf_lttng_live_iterator_status lttng_live_iterator_next_handle_one_active_data_stream(
+		struct lttng_live_component *lttng_live,
+		struct lttng_live_stream_iterator *lttng_live_stream,
+		struct bt_notification **notification)
+{
+	enum bt_ctf_lttng_live_iterator_status ret =
+			BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK;
+	enum bt_ctf_notif_iter_status status;
+	struct lttng_live_session *session;
+
+	bt_list_for_each_entry(session, &lttng_live->sessions, node) {
+		struct lttng_live_trace *trace;
+
+		if (session->new_streams_needed) {
+			return BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
+		}
+		bt_list_for_each_entry(trace, &session->traces, node) {
+			if (trace->new_metadata_needed) {
+				return BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
+			}
+		}
+	}
+
+	if (lttng_live_stream->state != LTTNG_LIVE_STREAM_ACTIVE_DATA) {
+		return BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_ERROR;
+	}
+	if (lttng_live_stream->packet_end_notif_queue) {
+		*notification = lttng_live_stream->packet_end_notif_queue;
+		lttng_live_stream->packet_end_notif_queue = NULL;
+		status = BT_CTF_NOTIF_ITER_STATUS_OK;
+	} else {
+		status = bt_ctf_notif_iter_get_next_notification(
+				lttng_live_stream->notif_iter,
+				lttng_live_stream->trace->cc_prio_map,
+				notification);
+		if (status == BT_CTF_NOTIF_ITER_STATUS_OK) {
+			/*
+			 * Consider empty packets as inactivity.
+			 */
+			if (bt_notification_get_type(*notification) == BT_NOTIFICATION_TYPE_PACKET_END) {
+				lttng_live_stream->packet_end_notif_queue = *notification;
+				*notification = NULL;
+				return emit_inactivity_notification(lttng_live,
+						lttng_live_stream, notification,
+						lttng_live_stream->current_packet_end_timestamp);
+			}
+		}
+	}
+	switch (status) {
+	case BT_CTF_NOTIF_ITER_STATUS_EOF:
+		ret = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_END;
+		break;
+	case BT_CTF_NOTIF_ITER_STATUS_OK:
+		ret = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK;
+		break;
+	case BT_CTF_NOTIF_ITER_STATUS_AGAIN:
+		/*
+		 * Continue immediately (end of packet). The next
+		 * get_index may return AGAIN to delay the following
+		 * attempt.
+		 */
+		ret = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_CONTINUE;
+		break;
+	case BT_CTF_NOTIF_ITER_STATUS_INVAL:
+		/* No argument provided by the user, so don't return INVAL. */
+	case BT_CTF_NOTIF_ITER_STATUS_ERROR:
+	default:
+		ret = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_ERROR;
+		break;
+	}
+	return ret;
+}
+
+/*
+ * helper function:
+ *            handle_no_data_streams()
+ *              retry:
+ *                - for each ACTIVE_NO_DATA stream:
+ *                  - query relayd for stream data, or quiescence info.
+ *                    - if need metadata, get metadata, goto retry.
+ *                    - if new stream, get new stream as ACTIVE_NO_DATA, goto retry
+ *                  - if quiescent, move to QUIESCENT streams
+ *                  - if fetched data, move to ACTIVE_DATA streams
+ *                (at this point each stream either has data, or is quiescent)
+ *
+ *
+ * iterator_next:
+ *            handle_new_streams_and_metadata()
+ *                  - query relayd for known streams, add them as ACTIVE_NO_DATA
+ *                  - query relayd for metadata
+ *
+ *            call handle_active_no_data_streams()
+ *
+ *            handle_quiescent_streams()
+ *                - if at least one stream is ACTIVE_DATA:
+ *                  - peek stream event with lowest timestamp -> next_ts
+ *                  - for each quiescent stream
+ *                    - if next_ts >= quiescent end
+ *                      - set state to ACTIVE_NO_DATA
+ *                - else
+ *                  - for each quiescent stream
+ *                      - set state to ACTIVE_NO_DATA
+ *
+ *            call handle_active_no_data_streams()
+ *
+ *            handle_active_data_streams()
+ *                - if at least one stream is ACTIVE_DATA:
+ *                    - get stream event with lowest timestamp from heap
+ *                    - make that stream event the current notification.
+ *                    - move this stream heap position to its next event
+ *                      - if we need to fetch data from relayd, move
+ *                        stream to ACTIVE_NO_DATA.
+ *                    - return OK
+ *                - return AGAIN
+ *
+ * end criterion: ctrl-c on client. If relayd exits or the session
+ * closes on the relay daemon side, we keep on waiting for streams.
+ * Eventually handle --end timestamp (also an end criterion).
+ *
+ * When disconnected from relayd: try to re-connect endlessly.
+ */
+static
+struct bt_notification_iterator_next_return lttng_live_iterator_next_stream(
+		struct bt_private_notification_iterator *iterator,
+		struct lttng_live_stream_iterator *stream_iter)
+{
+	enum bt_ctf_lttng_live_iterator_status status;
+	struct bt_notification_iterator_next_return next_return;
+	struct lttng_live_component *lttng_live;
+
+	lttng_live = stream_iter->trace->session->lttng_live;
+retry:
+	print_stream_state(stream_iter);
+	next_return.notification = NULL;
+	status = lttng_live_iterator_next_handle_new_streams_and_metadata(lttng_live);
+	if (status != BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK) {
+		goto end;
+	}
+	status = lttng_live_iterator_next_handle_one_no_data_stream(
+			lttng_live, stream_iter);
+	if (status != BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK) {
+		goto end;
+	}
+	status = lttng_live_iterator_next_handle_one_quiescent_stream(
+			lttng_live, stream_iter, &next_return.notification);
+	if (status != BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK) {
+		assert(next_return.notification == NULL);
+		goto end;
+	}
+	if (next_return.notification) {
+		goto end;
+	}
+	status = lttng_live_iterator_next_handle_one_active_data_stream(lttng_live,
+			stream_iter, &next_return.notification);
+	if (status != BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK) {
+		assert(next_return.notification == NULL);
+	}
+
+end:
+	switch (status) {
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_CONTINUE:
+		print_dbg("continue");
+		goto retry;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_AGAIN;
+		print_dbg("again");
+		break;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_END:
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_END;
+		print_dbg("end");
+		break;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK:
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_OK;
+		print_dbg("ok");
+		break;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_INVAL:
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_INVALID;
+		break;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_NOMEM;
+		break;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_UNSUPPORTED;
+		break;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_ERROR:
+	default:	/* fall-through */
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_ERROR;
+		break;
+	}
+	return next_return;
+}
+
+static
+struct bt_notification_iterator_next_return lttng_live_iterator_next_no_stream(
+		struct bt_private_notification_iterator *iterator,
+		struct lttng_live_no_stream_iterator *no_stream_iter)
+{
+	enum bt_ctf_lttng_live_iterator_status status;
+	struct bt_notification_iterator_next_return next_return;
+	struct lttng_live_component *lttng_live;
+
+	lttng_live = no_stream_iter->lttng_live;
+retry:
+	lttng_live_force_new_streams_and_metadata(lttng_live);
+	status = lttng_live_iterator_next_handle_new_streams_and_metadata(lttng_live);
+	if (status != BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK) {
+		goto end;
+	}
+	if (no_stream_iter->port) {
+		status = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_AGAIN;
+	} else {
+		status = BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_END;
+	}
+end:
+	switch (status) {
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_CONTINUE:
+		goto retry;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_AGAIN:
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_AGAIN;
+		break;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_END:
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_END;
+		break;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_OK:
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_OK;
+		break;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_INVAL:
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_INVALID;
+		break;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_NOMEM:
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_NOMEM;
+		break;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_UNSUPPORTED:
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_UNSUPPORTED;
+		break;
+	case BT_CTF_LTTNG_LIVE_ITERATOR_STATUS_ERROR:
+	default:	/* fall-through */
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_ERROR;
+		break;
+	}
+	return next_return;
+}
+
+BT_HIDDEN
+struct bt_notification_iterator_next_return lttng_live_iterator_next(
+		struct bt_private_notification_iterator *iterator)
+{
+	struct lttng_live_stream_iterator_generic *s =
+			bt_private_notification_iterator_get_user_data(iterator);
+	struct bt_notification_iterator_next_return next_return;
+
+	switch (s->type) {
+	case LIVE_STREAM_TYPE_NO_STREAM:
+		next_return = lttng_live_iterator_next_no_stream(iterator,
+			container_of(s, struct lttng_live_no_stream_iterator, p));
+		break;
+	case LIVE_STREAM_TYPE_STREAM:
+		next_return = lttng_live_iterator_next_stream(iterator,
+			container_of(s, struct lttng_live_stream_iterator, p));
+		break;
+	default:
+		next_return.status = BT_NOTIFICATION_ITERATOR_STATUS_ERROR;
+		break;
+	}
+	return next_return;
+}
+
+BT_HIDDEN
+enum bt_notification_iterator_status lttng_live_iterator_init(
+		struct bt_private_notification_iterator *it,
+		struct bt_private_port *port)
+{
+	enum bt_notification_iterator_status ret =
+			BT_NOTIFICATION_ITERATOR_STATUS_OK;
+	struct lttng_live_stream_iterator_generic *s;
+	struct lttng_live_component *lttng_live;
+
+	assert(it);
+
+	s = bt_private_port_get_user_data(port);
+	assert(s);
+	switch (s->type) {
+	case LIVE_STREAM_TYPE_NO_STREAM:
+	{
+		struct lttng_live_no_stream_iterator *no_stream_iter =
+			container_of(s, struct lttng_live_no_stream_iterator, p);
+		lttng_live = no_stream_iter->lttng_live;
+		ret = bt_private_notification_iterator_set_user_data(it, no_stream_iter);
+		if (ret) {
+			goto error;
+		}
+		break;
+	}
+	case LIVE_STREAM_TYPE_STREAM:
+	{
+		struct lttng_live_stream_iterator *stream_iter =
+			container_of(s, struct lttng_live_stream_iterator, p);
+		lttng_live = stream_iter->trace->session->lttng_live;
+		ret = bt_private_notification_iterator_set_user_data(it, stream_iter);
+		if (ret) {
+			goto error;
+		}
+		break;
+	}
+	default:
+		ret = BT_NOTIFICATION_ITERATOR_STATUS_ERROR;
+		goto end;
+	}
+
+end:
+	return ret;
+error:
+	if (bt_private_notification_iterator_set_user_data(it, NULL)
+			!= BT_NOTIFICATION_ITERATOR_STATUS_OK) {
+		PERR("Error setting private data to NULL\n");
+	}
+	goto end;
+}
+
+static
+struct bt_value *lttng_live_query_list_sessions(struct bt_component_class *comp_class,
+		struct bt_value *params)
+{
+	struct bt_value *url_value = NULL;
+	struct bt_value *results = NULL;
+	const char *url;
+	struct bt_live_viewer_connection *viewer_connection = NULL;
+	enum bt_value_status ret;
+
+	url_value = bt_value_map_get(params, "url");
+	if (!url_value || bt_value_is_null(url_value) || !bt_value_is_string(url_value)) {
+		fprintf(stderr, "Mandatory \"url\" parameter missing\n");
+		goto error;
+	}
+
+	ret = bt_value_string_get(url_value, &url);
+	if (ret != BT_VALUE_STATUS_OK) {
+		fprintf(stderr, "\"url\" parameter is required to be a string value\n");
+		goto error;
+	}
+
+	viewer_connection = bt_live_viewer_connection_create(url, stderr);
+	if (!viewer_connection) {
+		ret = BT_COMPONENT_STATUS_NOMEM;
+		goto error;
+	}
+
+	results = bt_live_viewer_connection_list_sessions(viewer_connection);
+	goto end;
+error:
+	BT_PUT(results);
+end:
+	if (viewer_connection) {
+		bt_live_viewer_connection_destroy(viewer_connection);
+	}
+	BT_PUT(url_value);
+	return results;
+}
+
 BT_HIDDEN
-struct bt_notification *lttng_live_iterator_get(
-		struct bt_notification_iterator *iterator)
+struct bt_value *lttng_live_query(struct bt_component_class *comp_class,
+		const char *object, struct bt_value *params)
 {
+	if (strcmp(object, "sessions") == 0) {
+		return lttng_live_query_list_sessions(comp_class,
+			params);
+	}
+	fprintf(stderr, "Unknown query object `%s`\n", object);
 	return NULL;
 }
 
+static
+void lttng_live_component_destroy_data(struct lttng_live_component *lttng_live)
+{
+	int ret;
+	struct lttng_live_session *session, *s;
+
+	bt_list_for_each_entry_safe(session, s, &lttng_live->sessions, node) {
+		lttng_live_destroy_session(session);
+	}
+	BT_PUT(lttng_live->viewer_connection);
+	if (lttng_live->url) {
+		g_string_free(lttng_live->url, TRUE);
+	}
+	if (lttng_live->no_stream_port) {
+		ret = bt_private_port_remove_from_component(lttng_live->no_stream_port);
+		assert(!ret);
+		BT_PUT(lttng_live->no_stream_port);
+	}
+	if (lttng_live->no_stream_iter) {
+		g_free(lttng_live->no_stream_iter);
+	}
+	g_free(lttng_live);
+}
+
 BT_HIDDEN
-enum bt_notification_iterator_status lttng_live_iterator_next(
-		struct bt_notification_iterator *iterator)
+void lttng_live_component_finalize(struct bt_private_component *component)
 {
-	return BT_NOTIFICATION_ITERATOR_STATUS_OK;
+	void *data = bt_private_component_get_user_data(component);
+
+	if (!data) {
+		return;
+	}
+	lttng_live_component_destroy_data(data);
+}
+
+static
+struct lttng_live_component *lttng_live_component_create(struct bt_value *params,
+		struct bt_private_component *private_component)
+{
+	struct lttng_live_component *lttng_live;
+	struct bt_value *value = NULL;
+	const char *url;
+	enum bt_value_status ret;
+
+	lttng_live = g_new0(struct lttng_live_component, 1);
+	if (!lttng_live) {
+		goto end;
+	}
+	lttng_live->error_fp = stderr;
+	/* TODO: make this an overridable parameter. */
+	lttng_live->max_query_size = MAX_QUERY_SIZE;
+	BT_INIT_LIST_HEAD(&lttng_live->sessions);
+	value = bt_value_map_get(params, "url");
+	if (!value || bt_value_is_null(value) || !bt_value_is_string(value)) {
+		fprintf(stderr, "Mandatory \"url\" parameter missing\n");
+		goto error;
+	}
+	ret = bt_value_string_get(value, &url);
+	if (ret != BT_VALUE_STATUS_OK) {
+		fprintf(stderr, "\"url\" parameter is required to be a string value\n");
+		goto error;
+	}
+	lttng_live->url = g_string_new(url);
+	if (!lttng_live->url) {
+		goto error;
+	}
+	lttng_live->viewer_connection =
+		bt_live_viewer_connection_create(lttng_live->url->str,
+			stderr);
+	if (!lttng_live->viewer_connection) {
+		ret = BT_COMPONENT_STATUS_NOMEM;
+		goto error;
+	}
+	if (lttng_live_create_viewer_session(lttng_live)) {
+		ret = BT_COMPONENT_STATUS_ERROR;
+		goto error;
+	}
+	lttng_live->private_component = private_component;
+
+	goto end;
+
+error:
+	lttng_live_component_destroy_data(lttng_live);
+	lttng_live = NULL;
+end:
+	return lttng_live;
 }
 
 BT_HIDDEN
-enum bt_component_status lttng_live_init(struct bt_component *component,
-		struct bt_value *params, UNUSED_VAR void *init_method_data)
+enum bt_component_status lttng_live_component_init(struct bt_private_component *component,
+		struct bt_value *params, void *init_method_data)
 {
-	return BT_COMPONENT_STATUS_OK;
+	struct lttng_live_component *lttng_live;
+	enum bt_component_status ret = BT_COMPONENT_STATUS_OK;
+
+	lttng_live_debug = g_strcmp0(getenv("LTTNG_LIVE_DEBUG"), "1") == 0;
+
+	/* Passes ownership of iter ref to lttng_live_component_create. */
+	lttng_live = lttng_live_component_create(params, component);
+	if (!lttng_live) {
+		ret = BT_COMPONENT_STATUS_NOMEM;
+		goto end;
+	}
+
+	lttng_live->no_stream_iter = g_new0(struct lttng_live_no_stream_iterator, 1);
+	lttng_live->no_stream_iter->p.type = LIVE_STREAM_TYPE_NO_STREAM;
+	lttng_live->no_stream_iter->lttng_live = lttng_live;
+
+	lttng_live->no_stream_port =
+		bt_private_component_source_add_output_private_port(
+				lttng_live->private_component, "no-stream",
+				lttng_live->no_stream_iter);
+	lttng_live->no_stream_iter->port = lttng_live->no_stream_port;
+
+	ret = bt_private_component_set_user_data(component, lttng_live);
+	if (ret != BT_COMPONENT_STATUS_OK) {
+		goto error;
+	}
+
+end:
+	return ret;
+error:
+	(void) bt_private_component_set_user_data(component, NULL);
+	lttng_live_component_destroy_data(lttng_live);
+	return ret;
 }