From: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Date: Tue, 7 Apr 2020 20:27:05 +0000 (-0400)
Subject: Fix: load: incomplete error handling for load_session_from_file
X-Git-Tag: v2.11.4~3
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=92dbeff150951f4827c209028cacd035caf15288

Fix: load: incomplete error handling for load_session_from_file

Observed issue
==============
lttng-ivc test fails to fail.

test_save_load_blocking_timeout[lttng-tools-2.12-lttng-tools-2.11-False]

Here we load a xml created by lttng-tools-2.12 and try to load it using
lttng-tools 2.11. We expect this to fail on the load.

The command report an error on the stderr but the command return code
value is zero.

From lttng-ivc test runtime.log:
Command #0
  Return value: 0
  Command: lttng load --input-path=/home/joraj/lttng/lttng-ivc/.tox/py3/tmp/test_save_load_blocking_timeou0/save_load saved_trace
  STDOUT:
      Session saved_trace has been loaded successfully
  STDERR:
      XML Error: Element 'process_attr_trackers': This element is not expected.
      Error: Session configuration file validation failed

Cause
==============
The error coming from load_session_from_file is not handled correctly.

Solution
========

Rework error handling in load_session_from_path and
load_session_from_file.

LTTNG_ERR_LOAD_SESSION_NOENT is NOT an error when session_name is
specified in load_session_from_path. In this scenario, we are actively
looking for the configuration of the session.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I0fea474045b718664e70ffe169e4e4fa125791a8
---

diff --git a/src/common/config/session-config.c b/src/common/config/session-config.c
index b1fa992fe..86afc2439 100644
--- a/src/common/config/session-config.c
+++ b/src/common/config/session-config.c
@@ -3309,10 +3309,24 @@ int load_session_from_file(const char *path, const char *session_name,
 			xmlNextElementSibling(session_node)) {
 		ret = process_session_node(session_node,
 			session_name, overwrite, overrides);
-		if (session_name && ret == 0) {
-			/* Target session found and loaded */
-			session_found = 1;
-			break;
+		if (!session_name && ret) {
+			/* Loading error occurred. */
+			goto end;
+		} else if (session_name) {
+			if (ret == 0) {
+				/* Target session found and loaded */
+				session_found = 1;
+				break;
+			} else if (ret == -LTTNG_ERR_NO_SESSION) {
+				/*
+				 * Ignore this error, we are looking for the
+				 * session.
+				 */
+				ret = 0;
+			} else {
+				/* Loading error occurred. */
+				goto end;
+			}
 		}
 	}
 end:
@@ -3444,10 +3458,27 @@ int load_session_from_path(const char *path, const char *session_name,
 
 			ret = load_session_from_file(file_path.data, session_name,
 				validation_ctx, overwrite, overrides);
-			if (session_name && !ret) {
-				session_found = 1;
-				break;
+			if (!session_name && ret) {
+				/* Loading error occured. */
+				goto end;
+			} else if (session_name) {
+				if (ret == 0) {
+					/* Target session found and loaded */
+					session_found = 1;
+					break;
+				} else if (ret ==
+						-LTTNG_ERR_LOAD_SESSION_NOENT) {
+					/*
+					 * Ignore this error, we are looking for
+					 * the session.
+					 */
+					ret = 0;
+				} else {
+					/* Loading error occured. */
+					goto end;
+				}
 			}
+
 			/*
 			 * Reset the buffer's size to the location of the
 			 * path's trailing '/'.