From acd0c7156c5baf2d0c13b21f198097f634e4f89e Mon Sep 17 00:00:00 2001
From: Holger Vogt <holger.vogt@uni-due.de>
Date: Fri, 20 Sep 2019 19:22:47 +0200
Subject: [PATCH] return immediately if empty commands are sent

---
 src/sharedspice.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/sharedspice.c b/src/sharedspice.c
index a492f3e1c..24352eee1 100644
--- a/src/sharedspice.c
+++ b/src/sharedspice.c
@@ -916,6 +916,16 @@ immediately */
 IMPEXP
 int  ngSpice_Command(char* comexec)
 {
+    /* Check if command is reasonable */
+    if (comexec == NULL) {
+        fprintf(stderr, "Warning: Received command NULL, ignored");
+        return 1;
+    }
+    if (*comexec == '\0') {
+        fprintf(stderr, "Warning: Received empty string as command, ignored");
+        return 1;
+    }
+
     if ( ! setjmp(errbufc) ) {
 
         immediate = FALSE;