sessiond: introduce ltt_session::locked_ref look-up functions

[lttng-tools.git] / src / bin / lttng-sessiond / save.cpp

diff --git a/src/bin/lttng-sessiond/save.cpp b/src/bin/lttng-sessiond/save.cpp
index b4ca4c080fdd8f119a98a2fe31682be6d9cec42e..484bf7c906a665a7fe9cc3a70c737c7a54a79ad9 100644 (file)
--- a/src/bin/lttng-sessiond/save.cpp
+++ b/src/bin/lttng-sessiond/save.cpp
@@ -2737,27 +2737,36 @@ int cmd_save_sessions(struct lttng_save_session_attr *attr, lttng_sock_cred *cre
 {
        int ret;
        const char *session_name;
-       struct ltt_session *session;
 
-       session_lock_list();
+       const auto list_lock = lttng::sessiond::lock_session_list();
 
        session_name = lttng_save_session_attr_get_session_name(attr);
        if (session_name) {
-               session = session_find_by_name(session_name);
-               if (!session) {
+
+               /*
+               * Mind the order of the declaration of list_lock vs session:
+               * the session list lock must always be released _after_ the release of
+               * a session's reference (the destruction of a ref/locked_ref) to ensure
+               * since the reference's release may unpublish the session from the list of
+               * sessions.
+               */
+               ltt_session::locked_ref session;
+
+               try {
+                       session = ltt_session::find_locked_session(session_name);
+               } catch (const lttng::sessiond::exceptions::session_not_found_error& ex) {
+                       WARN_FMT("Failed to save session: {} {}", ex.what(), ex.source_location);
                        ret = LTTNG_ERR_SESS_NOT_FOUND;
-                       goto end;
+                       return ret;
                }
 
-               session_lock(session);
-               ret = save_session(session, attr, creds);
-               session_unlock(session);
-               session_put(session);
+               ret = save_session(session.get(), attr, creds);
                if (ret != LTTNG_OK) {
-                       goto end;
+                       return ret;
                }
        } else {
                struct ltt_session_list *list = session_get_list();
+               struct ltt_session *session;
 
                cds_list_for_each_entry (session, &list->head, list) {
                        if (!session_get(session)) {
@@ -2769,13 +2778,10 @@ int cmd_save_sessions(struct lttng_save_session_attr *attr, lttng_sock_cred *cre
                        session_put(session);
                        /* Don't abort if we don't have the required permissions. */
                        if (ret != LTTNG_OK && ret != LTTNG_ERR_EPERM) {
-                               goto end;
+                               return ret;
                        }
                }
        }
-       ret = LTTNG_OK;
 
-end:
-       session_unlock_list();
-       return ret;
+       return LTTNG_OK;
 }