From c01430e3fce8289eb055b089ab4278ade6f6f34f Mon Sep 17 00:00:00 2001
From: Markus Makela <markus.makela@mariadb.com>
Date: Mon, 28 Nov 2016 23:18:38 +0200
Subject: [PATCH] Fix module commands with no arguments

Passing zero as the argument count would lead to a malloc for zero
bytes which would always cause a failure.
---
 server/core/modulecmd.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/server/core/modulecmd.c b/server/core/modulecmd.c
index b3e3c870c..018f7bb97 100644
--- a/server/core/modulecmd.c
+++ b/server/core/modulecmd.c
@@ -136,10 +136,11 @@ static MODULECMD* command_create(const char *identifier, const char *domain,
                                  MODULECMDFN entry_point, int argc,
                                  modulecmd_arg_type_t* argv)
 {
+    ss_dassert((argc && argv) || (argc == 0 && argv == NULL));
     MODULECMD *rval = MXS_MALLOC(sizeof(*rval));
     char *id = MXS_STRDUP(identifier);
     char *dm = MXS_STRDUP(domain);
-    modulecmd_arg_type_t *types = MXS_MALLOC(sizeof(*types) * argc);
+    modulecmd_arg_type_t *types = MXS_MALLOC(sizeof(*types) * (argc ? argc : 1));
 
     if (rval && id  && dm && types)
     {
@@ -154,6 +155,13 @@ static MODULECMD* command_create(const char *identifier, const char *domain,
             types[i] = argv[i];
         }
 
+        if (argc == 0)
+        {
+            /** The command requires no arguments */
+            types[0].type = MODULECMD_ARG_NONE;
+            types[0].description = "";
+        }
+
         rval->func = entry_point;
         rval->identifier = id;
         rval->domain = dm;