From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Fri, 7 Nov 2014 23:07:07 +0000 (-0500)
Subject: Fix: Don't report an error when listing a session with no channels
X-Git-Tag: v2.4.3~40
X-Git-Url: https://git.liburcu.org/?p=lttng-tools.git;a=commitdiff_plain;h=22aca9f6954179e10aeed2e1a5719a2f13600eae

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>

Conflicts:
	src/bin/lttng/commands/list.c
---

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index 8f8278eec..022d5cee1 100644
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -2388,12 +2388,12 @@ 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;
 	}
@@ -2406,10 +2406,6 @@ 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 a95f269d0..e8e451152 100644
--- a/src/bin/lttng-sessiond/main.c
+++ b/src/bin/lttng-sessiond/main.c
@@ -3315,7 +3315,7 @@ 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 0b1eff265..dd39c4fc5 100644
--- a/src/bin/lttng/commands/list.c
+++ b/src/bin/lttng/commands/list.c
@@ -688,7 +688,7 @@ static int list_channels(const char *channel_name)
 		goto error_channels;
 	}
 
-	if (channel_name == NULL) {
+	if (count) {
 		MSG("Channels:\n-------------");
 	}