rrdtool plugin: Make sure "cache_timeout + random_variation" dosn't get negative.

diff --git a/src/rrdtool.c b/src/rrdtool.c
index c948d1f803b282d0707b8daafa7d8571d61eee59..b366a9c64166eeeae135f700b069e81578cac28a 100644 (file)
--- a/src/rrdtool.c
+++ b/src/rrdtool.c
@@ -661,6 +661,14 @@ static int64_t rrd_get_random_variation (void)
   if (random_timeout <= 0)
     return (0);
 
+  /* Assure that "cache_timeout + random_variation" is never negative. */
+  if (random_timeout > cache_timeout)
+  {
+         INFO ("rrdtool plugin: Adjusting \"RandomTimeout\" to %.3f seconds.",
+                         CDTIME_T_TO_DOUBLE (cache_timeout));
+         random_timeout = cache_timeout;
+  }
+
   /* This seems a bit complicated, but "random_timeout" is likely larger than
    * RAND_MAX, so we can't simply use modulo here. */
   dbl_timeout = CDTIME_T_TO_DOUBLE (random_timeout);