From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Fri, 7 Nov 2014 22:58:15 +0000 (-0500)
Subject: Fix: Don't report an error when listing a session with no channels
X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=commitdiff_plain;h=ade7ce5245446944d27824943142773f7e4d0674

Fix: Don't report an error when listing a session with no channels

The LTTng sessiond daemon reports an error when the list_channel
command is invoked on a session which only has a metadata channel.

The error lies in assuming that a session which has an enabled
domains also has (user-visible) channels.

The metadata channel should be listed in a future fix.

Fixes #855

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index 98e090539..17091de09 100644
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -2451,12 +2451,12 @@ ssize_t cmd_list_channels(int domain, struct ltt_session *session,
 					session->ust_session->domain_global.channels);
 		}
 		DBG3("Number of UST global channels %zd", nb_chan);
-		if (nb_chan <= 0) {
+		if (nb_chan < 0) {
 			ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
+			goto error;
 		}
 		break;
 	default:
-		*channels = NULL;
 		ret = LTTNG_ERR_UND;
 		goto error;
 	}
@@ -2469,10 +2469,6 @@ ssize_t cmd_list_channels(int domain, struct ltt_session *session,
 		}
 
 		list_lttng_channels(domain, session, *channels);
-	} else {
-		*channels = NULL;
-		/* Ret value was set in the domain switch case */
-		goto error;
 	}
 
 	return nb_chan;
diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
index c8484b93c..9542e650d 100644
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -3501,7 +3501,7 @@ skip_domain:
 	case LTTNG_LIST_CHANNELS:
 	{
 		int nb_chan;
-		struct lttng_channel *channels;
+		struct lttng_channel *channels = NULL;
 
 		nb_chan = cmd_list_channels(cmd_ctx->lsm->domain.type,
 				cmd_ctx->session, &channels);
diff --git a/src/bin/lttng/commands/list.c b/src/bin/lttng/commands/list.c
index 7c3211a59..12499ee40 100644
--- a/src/bin/lttng/commands/list.c
+++ b/src/bin/lttng/commands/list.c
@@ -1207,7 +1207,7 @@ static int list_channels(const char *channel_name)
 		}
 	} else {
 		/* Pretty print */
-		if (channel_name == NULL) {
+		if (count) {
 			MSG("Channels:\n-------------");
 		}