session BUGFIX thread-safe var access

Fixes #371

Author: michalvasko

src/session.c

@@ -189,9 +189,9 @@ nc_new_session(NC_SIDE side, int shared_ti)
     sess->side = side;
 
     if (side == NC_SERVER) {
+        pthread_mutex_init(&sess->opts.server.ntf_status_lock, NULL);
         pthread_mutex_init(&sess->opts.server.rpc_lock, NULL);
         pthread_cond_init(&sess->opts.server.rpc_cond, NULL);
-        sess->opts.server.rpc_inuse = 0;
 
         pthread_mutex_init(&sess->opts.server.ch_lock, NULL);
         pthread_cond_init(&sess->opts.server.ch_cond, NULL);
@@ -894,6 +894,7 @@ nc_session_free(struct nc_session *session, void (*data_free)(void *))
 
     /* final cleanup */
     if (session->side == NC_SERVER) {
+        pthread_mutex_destroy(&session->opts.server.ntf_status_lock);
         if (rpc_locked) {
             nc_session_rpc_unlock(session, NC_SESSION_LOCK_TIMEOUT, __func__);
         }

src/session_p.h

@@ -453,7 +453,9 @@ struct nc_session {
             /* server side only data */
             time_t session_start;          /**< real time the session was created */
             time_t last_rpc;               /**< monotonic time (seconds) the last RPC was received on this session */
-            int ntf_status;                /**< flag (count) whether the session is subscribed to notifications */
+
+            pthread_mutex_t ntf_status_lock;    /**< lock for ntf_status */
+            uint32_t ntf_status;                /**< flag (count) whether the session is subscribed to notifications */
 
             pthread_mutex_t rpc_lock;    /**< lock indicating RPC processing, this lock is always locked before io_lock!! */
             pthread_cond_t rpc_cond;     /**< RPC condition (tied with rpc_lock and rpc_inuse) */

src/session_server.c

@@ -1396,7 +1396,7 @@ nc_server_notif_send(struct nc_session *session, struct nc_server_notif *notif,
     NC_MSG_TYPE ret;
 
     /* check parameters */
-    if (!session || (session->side != NC_SERVER) || !session->opts.server.ntf_status) {
+    if (!session || (session->side != NC_SERVER) || !nc_session_get_notif_status(session)) {
         ERRARG("session");
         return NC_MSG_ERROR;
     } else if (!notif || !notif->ntf || !notif->eventtime) {
@@ -1505,7 +1505,7 @@ nc_ps_poll_session_io(struct nc_session *session, int io_timeout, time_t now_mon
 #endif
 
     /* check timeout first */
-    if (!(session->flags & NC_SESSION_CALLHOME) && !session->opts.server.ntf_status && server_opts.idle_timeout &&
+    if (!(session->flags & NC_SESSION_CALLHOME) && !nc_session_get_notif_status(session) && server_opts.idle_timeout &&
             (now_mono >= session->opts.server.last_rpc + server_opts.idle_timeout)) {
         sprintf(msg, "session idle timeout elapsed");
         session->status = NC_STATUS_INVALID;
@@ -3443,7 +3443,7 @@ nc_server_ch_client_thread_session_cond_wait(struct nc_session *session, struct
         }
 
         nc_gettimespec_mono(&ts);
-        if (!session->opts.server.ntf_status && idle_timeout && (ts.tv_sec >= session->opts.server.last_rpc + idle_timeout)) {
+        if (!nc_session_get_notif_status(session) && idle_timeout && (ts.tv_sec >= session->opts.server.last_rpc + idle_timeout)) {
             VRB(session, "Call Home client \"%s\": session idle timeout elapsed.", client->name);
             session->status = NC_STATUS_INVALID;
             session->term_reason = NC_SESSION_TERM_TIMEOUT;
@@ -3690,7 +3690,13 @@ nc_session_inc_notif_status(struct nc_session *session)
         return;
     }
 
+    /* NTF STATUS LOCK */
+    pthread_mutex_lock(&session->opts.server.ntf_status_lock);
+
     ++session->opts.server.ntf_status;
+
+    /* NTF STATUS UNLOCK */
+    pthread_mutex_unlock(&session->opts.server.ntf_status_lock);
 }
 
 API void
@@ -3701,20 +3707,36 @@ nc_session_dec_notif_status(struct nc_session *session)
         return;
     }
 
+    /* NTF STATUS LOCK */
+    pthread_mutex_lock(&session->opts.server.ntf_status_lock);
+
     if (session->opts.server.ntf_status) {
         --session->opts.server.ntf_status;
     }
+
+    /* NTF STATUS UNLOCK */
+    pthread_mutex_unlock(&session->opts.server.ntf_status_lock);
 }
 
 API int
 nc_session_get_notif_status(const struct nc_session *session)
 {
+    uint32_t ntf_status;
+
     if (!session || (session->side != NC_SERVER)) {
         ERRARG("session");
         return 0;
     }
 
-    return session->opts.server.ntf_status;
+    /* NTF STATUS LOCK */
+    pthread_mutex_lock(&((struct nc_session *)session)->opts.server.ntf_status_lock);
+
+    ntf_status = session->opts.server.ntf_status;
+
+    /* NTF STATUS UNLOCK */
+    pthread_mutex_unlock(&((struct nc_session *)session)->opts.server.ntf_status_lock);
+
+    return ntf_status;
 }
 
 API int