X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fcmd.c;h=c1f5a4e70b7ce83545ce0858db2f781b563fdc26;hb=b747c300c074c13b115d7f6d3f35d157e1c33f32;hp=f997cc79b3c6f5a89865250327ccb0477da69900;hpb=72b6f5b6dc9fdd0ff4d49df8a9f010644311e863;p=lttng-tools.git

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index f997cc79b..c1f5a4e70 100644
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -850,6 +850,16 @@ int cmd_enable_channel(struct ltt_session *session,
 
 	rcu_read_lock();
 
+	/*
+	 * The ringbuffer (both in user space and kernel) behave badly in overwrite
+	 * mode and with less than 2 subbuf so block it right away and send back an
+	 * invalid attribute error.
+	 */
+	if (attr->attr.overwrite && attr->attr.num_subbuf < 2) {
+		ret = LTTNG_ERR_INVALID;
+		goto error;
+	}
+
 	switch (domain->type) {
 	case LTTNG_DOMAIN_KERNEL:
 	{
@@ -1583,6 +1593,7 @@ error:
 int cmd_start_trace(struct ltt_session *session)
 {
 	int ret;
+	unsigned long nb_chan = 0;
 	struct ltt_kernel_session *ksession;
 	struct ltt_ust_session *usess;
 
@@ -1598,6 +1609,21 @@ int cmd_start_trace(struct ltt_session *session)
 		goto error;
 	}
 
+	/*
+	 * Starting a session without channel is useless since after that it's not
+	 * possible to enable channel thus inform the client.
+	 */
+	if (usess && usess->domain_global.channels) {
+		nb_chan += lttng_ht_get_count(usess->domain_global.channels);
+	}
+	if (ksession) {
+		nb_chan += ksession->channel_count;
+	}
+	if (!nb_chan) {
+		ret = LTTNG_ERR_NO_CHANNEL;
+		goto error;
+	}
+
 	session->enabled = 1;
 
 	/* Kernel tracing */
@@ -1753,6 +1779,17 @@ int cmd_set_consumer_uri(int domain, struct ltt_session *session,
 		}
 	}
 
+	/*
+	 * Make sure to set the session in output mode after we set URI since a
+	 * session can be created without URL (thus flagged in no output mode).
+	 */
+	session->output_traces = 1;
+	if (ksess) {
+		ksess->output_traces = 1;
+	} else if (usess) {
+		usess->output_traces = 1;
+	}
+
 	/* All good! */
 	ret = LTTNG_OK;
 
@@ -2285,6 +2322,21 @@ int cmd_data_pending(struct ltt_session *session)
 	if (session->enabled) {
 		ret = LTTNG_ERR_SESSION_STARTED;
 		goto error;
+	} else {
+		/*
+		 * If stopped, just make sure we've started before else the above call
+		 * will always send that there is data pending.
+		 *
+		 * The consumer assumes that when the data pending command is received,
+		 * the trace has been started before or else no output data is written
+		 * by the streams which is a condition for data pending. So, this is
+		 * *VERY* important that we don't ask the consumer before a start
+		 * trace.
+		 */
+		if (!session->started) {
+			ret = 0;
+			goto error;
+		}
 	}
 
 	if (ksess && ksess->consumer) {
@@ -2637,12 +2689,17 @@ static int record_ust_snapshot(struct ltt_ust_session *usess,
 
 	ret = ust_app_snapshot_record(usess, output, wait, nb_streams);
 	if (ret < 0) {
-		if (ret == -EINVAL) {
+		switch (-ret) {
+		case EINVAL:
 			ret = LTTNG_ERR_INVALID;
-			goto error_snapshot;
+			break;
+		case ENODATA:
+			ret = LTTNG_ERR_SNAPSHOT_NODATA;
+			break;
+		default:
+			ret = LTTNG_ERR_SNAPSHOT_FAIL;
+			break;
 		}
-
-		ret = LTTNG_ERR_SNAPSHOT_FAIL;
 		goto error_snapshot;
 	}