Fix: error handling on relay version check

If a network error occurs while performing the version check between
the session daemon and the relay, we should not report to the user that
there is a version mismatch. LTTNG_ERR_RELAYD_VERSION_FAIL is now
returned by relayd_version_check() when the daemons are not compatible
while a negative value is returned if sendmsg()/recvmsg() fail on
network errors.

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
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 edb5a3433049da305ddc11563f4612285a3bb1c6..23c6c31a2fc05528476cd5f9d99ba9a1410a72ba 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -856,8 +856,11 @@ static int create_connect_relayd(struct lttng_uri *uri,
 
                /* Check relayd version */
                ret = relayd_version_check(rsock);
-               if (ret < 0) {
-                       ret = LTTNG_ERR_RELAYD_VERSION_FAIL;
+               if (ret == LTTNG_ERR_RELAYD_VERSION_FAIL) {
+                       goto close_sock;
+               } else if (ret < 0) {
+                       ERR("Unable to reach lttng-relayd");
+                       ret = LTTNG_ERR_RELAYD_CONNECT_FAIL;
                        goto close_sock;
                }
                consumer->relay_major_version = rsock->major;

diff --git a/src/common/relayd/relayd.c b/src/common/relayd/relayd.c
index 2adcbe415c63f16a176dba9167c247f34eb0eba3..4cb1c1fd339d248d028901ad4c390faa8b1f654e 100644 (file)
--- a/src/common/relayd/relayd.c
+++ b/src/common/relayd/relayd.c
@@ -378,7 +378,8 @@ end:
  * If major versions are compatible, we assign minor_to_use to the
  * minor version of the procotol we are going to use for this session.
  *
- * Return 0 if compatible else negative value.
+ * Return 0 if the two daemons are compatible, LTTNG_ERR_RELAYD_VERSION_FAIL
+ * otherwise, or a negative value on network errors.
  */
 int relayd_version_check(struct lttcomm_relayd_sock *rsock)
 {
@@ -420,7 +421,7 @@ int relayd_version_check(struct lttcomm_relayd_sock *rsock)
         */
        if (msg.major != rsock->major) {
                /* Not compatible */
-               ret = -1;
+               ret = LTTNG_ERR_RELAYD_VERSION_FAIL;
                DBG2("Relayd version is NOT compatible. Relayd version %u != %u (us)",
                                msg.major, rsock->major);
                goto error;