From: Julien Desfossez <jdesfossez@efficios.com>
Date: Thu, 23 Nov 2017 23:00:14 +0000 (-0500)
Subject: Fix: Make sure we have all the metadata streams before adding new traces
X-Git-Tag: v1.4.4~4
X-Git-Url: http://git.efficios.com/?p=babeltrace.git;a=commitdiff_plain;h=4a6f6ed3aeb9845dec4b8ec9ca8573ed1c064187

Fix: Make sure we have all the metadata streams before adding new traces

The add_one_trace function needs to have a metadata stream for all the
known traces. If it does not, we could end up in situations where we
fetch new streams while adding a trace which causes a lot of problems.

Now we ensure we have all the metadata streams before adding the traces.

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Acked-by: Jonathan Rajotte-Julien <jonathan.rajotte-julien@efficios.com>
Tested-by: Jonathan Rajotte-Julien <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/formats/lttng-live/lttng-live-comm.c b/formats/lttng-live/lttng-live-comm.c
index 0e51c0c2..b61371fc 100644
--- a/formats/lttng-live/lttng-live-comm.c
+++ b/formats/lttng-live/lttng-live-comm.c
@@ -1572,6 +1572,56 @@ end:
 	return ret;
 }
 
+/*
+ * Make sure all the traces we know have a metadata stream or loop on
+ * ask_new_streams until it is done. This must be called before we call
+ * add_one_trace.
+ *
+ * Return 0 when all known traces have a metadata stream, a negative value
+ * on error.
+ */
+static
+int check_traces_metadata(struct lttng_live_ctx *ctx)
+{
+	int ret;
+	struct lttng_live_ctf_trace *trace;
+	GHashTableIter it;
+	gpointer key;
+	gpointer value;
+
+retry:
+	g_hash_table_iter_init(&it, ctx->session->ctf_traces);
+	while (g_hash_table_iter_next(&it, &key, &value)) {
+		trace = (struct lttng_live_ctf_trace *) value;
+		printf_verbose("Check trace %" PRIu64 " metadata\n", trace->ctf_trace_id);
+		while (!trace->metadata_stream) {
+			printf_verbose("Waiting for metadata stream\n");
+			if (lttng_live_should_quit()) {
+				ret = 0;
+				goto end;
+			}
+			ret = ask_new_streams(ctx);
+			if (ret < 0) {
+				goto end;
+			} else if (ret == 0) {
+				(void) poll(NULL, 0, ACTIVE_POLL_DELAY);
+			} else {
+				/*
+				 * If ask_new_stream got streams from a trace we did not know
+				 * about until now, we have to reinitialize the iterator.
+				 */
+				goto retry;
+			}
+		}
+	}
+
+	ret = 0;
+
+end:
+	printf_verbose("End check traces metadata\n");
+	return ret;
+}
+
 static
 int add_traces(struct lttng_live_ctx *ctx)
 {
@@ -1582,6 +1632,12 @@ int add_traces(struct lttng_live_ctx *ctx)
 	gpointer value;
 
 	printf_verbose("Begin add traces\n");
+
+	ret = check_traces_metadata(ctx);
+	if (ret < 0) {
+		goto end;
+	}
+
 	g_hash_table_iter_init(&it, ctx->session->ctf_traces);
 	while (g_hash_table_iter_next(&it, &key, &value)) {
 		trace = (struct lttng_live_ctf_trace *) value;