handle buffer sizes safely in handler.c

src/handler.c

@@ -50,6 +50,7 @@
 
 #include "vas.h"
 #include "vsb.h"
+#include "vdef.h"
 
 #include "varnishevent.h"
 
@@ -104,7 +105,7 @@ symbol_hack(const char *a0)
     uintptr_t a;
     struct symbols *s;
 
-    sprintf(buf, "nm -an %s 2>/dev/null", a0);
+    bprintf(buf, "nm -an %s 2>/dev/null", a0);
     fi = popen(buf, "r");
     if (fi == NULL)
         return;