From 3f4c72d4f2cc6dc5ae095da1dc0e8ca6a2f9908c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Markus=20M=C3=A4kel=C3=A4?= <markus.makela@mariadb.com>
Date: Wed, 30 Jan 2019 15:26:55 +0200
Subject: [PATCH] MXS-2303: Fix missing parameter error

The detection of missing parameters that define which module to load must
be done before the module is loaded.
---
 server/core/config.cc | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/server/core/config.cc b/server/core/config.cc
index 8c3078929..d3d395a08 100644
--- a/server/core/config.cc
+++ b/server/core/config.cc
@@ -1291,6 +1291,34 @@ const MXS_MODULE* get_module(CONFIG_CONTEXT* obj, const char* param_name, const
     return module ? get_module(module, module_type) : NULL;
 }
 
+const char* get_missing_module_parameter_name(const CONFIG_CONTEXT* obj)
+{
+    std::string type = config_get_string(obj->parameters, CN_TYPE);
+
+    if (type == CN_SERVICE && !config_get_param(obj->parameters, CN_ROUTER))
+    {
+        return CN_ROUTER;
+    }
+    else if (type == CN_LISTENER && !config_get_param(obj->parameters, CN_PROTOCOL))
+    {
+        return CN_PROTOCOL;
+    }
+    else if (type == CN_SERVER && !config_get_param(obj->parameters, CN_PROTOCOL))
+    {
+        return CN_PROTOCOL;
+    }
+    else if (type == CN_MONITOR && !config_get_param(obj->parameters, CN_MODULE))
+    {
+        return CN_MODULE;
+    }
+    else if (type == CN_FILTER && !config_get_param(obj->parameters, CN_MODULE))
+    {
+        return CN_MODULE;
+    }
+
+    return nullptr;
+}
+
 std::pair<const MXS_MODULE_PARAM*, const MXS_MODULE*> get_module_details(const CONFIG_CONTEXT* obj)
 {
     std::string type = config_get_string(obj->parameters, CN_TYPE);
@@ -3044,6 +3072,15 @@ static bool check_config_objects(CONFIG_CONTEXT* context)
             continue;
         }
 
+        const char* no_module_defined = get_missing_module_parameter_name(obj);
+
+        if (no_module_defined)
+        {
+            MXS_ERROR("'%s' is missing the required parameter '%s'", obj->object, no_module_defined);
+            rval = false;
+            continue;
+        }
+
         const MXS_MODULE_PARAM* param_set = nullptr;
         const MXS_MODULE* mod = nullptr;
         std::tie(param_set, mod) = get_module_details(obj);