From: Tobias Oetiker <tobi@oetiker.ch>
Date: Tue, 19 Apr 2016 08:01:07 +0000 (+0200)
Subject: fix for #707
X-Git-Tag: v1.5.6~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3079839b38ca16686231bff5ac07ebdaf4912f31;p=thirdparty%2Frrdtool-1.x.git

fix for #707
---

diff --git a/src/rrd_rpncalc.c b/src/rrd_rpncalc.c
index 4258b099..bc6d430c 100644
--- a/src/rrd_rpncalc.c
+++ b/src/rrd_rpncalc.c
@@ -333,7 +333,10 @@ rpnp_t   *rpn_parse(
 
     rpnp = NULL;
     expr = (char *) expr_const;
-
+    if (! *expr){
+        rrd_set_error("can not parse an empty rpn expression");
+        return NULL;
+    }
     while (*expr) {
         if ((rpnp = (rpnp_t *) rrd_realloc(rpnp, (++steps + 2) *
                                            sizeof(rpnp_t))) == NULL) {