From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 5 Sep 2019 19:18:40 +0000 (-0400)
Subject: Fix: sessiond: handle NULL control output in session descriptor base path getter
X-Git-Tag: v2.11.0-rc3~7
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=1df4aefd2764d510e80633e289a629baf0aa3adb;p=lttng-tools.git

Fix: sessiond: handle NULL control output in session descriptor base path getter

Creating a session with "lttng create --live" without specifying any
URL triggers a SEGFAULT (dereferencing a NULL pointer) because the
output is not set when getting the session descriptor base path.

Indeed, the destination output URL will only be set later in
cmd_create_session_from_descriptor(), when setting the default output.

When the default output is used, no base path override is possible,
therefore it is fine to assign the base_path to NULL in the base path
getter.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/src/common/session-descriptor.c b/src/common/session-descriptor.c
index b5fdb0677..208eb46ff 100644
--- a/src/common/session-descriptor.c
+++ b/src/common/session-descriptor.c
@@ -1186,8 +1186,12 @@ int lttng_session_descriptor_get_base_path(struct lttng_session_descriptor *dst,
 	switch (dst->output_type) {
 	case LTTNG_SESSION_DESCRIPTOR_OUTPUT_TYPE_NETWORK:
 	{
-		*_base_path = dst->output.network.control->subdir[0] ?
-				dst->output.network.control->subdir : NULL;
+		if (dst->output.network.control &&
+				dst->output.network.control->subdir[0]) {
+			*_base_path = dst->output.network.control->subdir;
+		} else {
+			*_base_path = NULL;
+		}
 		break;
 	}
 	case LTTNG_SESSION_DESCRIPTOR_OUTPUT_TYPE_LOCAL: