lib REFACTOR safety checks (#548)

Author: jsc-se

src/io.c

@@ -649,14 +649,14 @@ nc_write_starttag_and_msg(struct nc_session *session, const void *buf, uint32_t
         r = sprintf(chunksize, "\n#%" PRIu32 "\n", count);
 
         r = nc_write(session, chunksize, r);
-        if (r == -1) {
+        if (r < 0) {
             return -1;
         }
         ret += r;
     }
 
     r = nc_write(session, buf, count);
-    if (r == -1) {
+    if (r < 0) {
         return -1;
     }
     ret += r;

src/server_config.c

@@ -2631,6 +2631,7 @@ nc_server_config_endpoint_reference(const struct lyd_node *node, enum nc_operati
             endpt->referenced_endpt_name = NULL;
         } else {
             /* call home */
+            assert(ch_endpt);
             free(ch_endpt->referenced_endpt_name);
             ch_endpt->referenced_endpt_name = NULL;
         }
@@ -2658,6 +2659,7 @@ nc_server_config_endpoint_reference(const struct lyd_node *node, enum nc_operati
             endpt->referenced_endpt_name = strdup(lyd_get_value(node));
             NC_CHECK_ERRMEM_GOTO(!endpt->referenced_endpt_name, ret = 1, cleanup);
         } else {
+            assert(ch_endpt);
             free(ch_endpt->referenced_endpt_name);
             ch_endpt->referenced_endpt_name = strdup(lyd_get_value(node));
             NC_CHECK_ERRMEM_GOTO(!ch_endpt->referenced_endpt_name, ret = 1, cleanup);

src/session_server.c

@@ -4072,7 +4072,9 @@ nc_server_notif_cert_exp_thread(void *arg)
     if (targ->clb_free_data) {
         targ->clb_free_data(targ->clb_data);
     }
-    nc_server_notif_cert_exp_dates_destroy(exp_dates, exp_date_count);
+    if (exp_dates) {
+        nc_server_notif_cert_exp_dates_destroy(exp_dates, exp_date_count);
+    }
     free(targ);
     return NULL;
 }