MXS-1731: Treat empty parameters as errors

If a parameter is defined without a value, it is now treated as an error.

maxscale-system-test/cnf/maxscale.cnf.template.mxs1731_empty_param

@@ -0,0 +1,59 @@
+[maxscale]
+threads=###threads###
+
+[server1]
+type=server
+address=###node_server_IP_1###
+port=###node_server_port_1###
+protocol=MySQLBackend
+
+[server2]
+type=server
+address=###node_server_IP_2###
+port=###node_server_port_2###
+protocol=MySQLBackend
+
+[server3]
+type=server
+address=###node_server_IP_3###
+port=###node_server_port_3###
+protocol=MySQLBackend
+
+[server4]
+type=server
+address=###node_server_IP_4###
+port=###node_server_port_4###
+protocol=MySQLBackend
+
+[MySQL Monitor]
+type=monitor
+module=mysqlmon
+###repl51###
+servers=server1,server2,server3,server4
+user=maxskysql
+passwd=skysql
+monitor_interval=1000
+
+[RW Split Router]
+type=service
+router=readwritesplit
+servers=server1,server2,server3,server4
+user=maxskysql
+passwd=skysql
+version_string=
+
+[RW Split Listener]
+type=listener
+service=RW Split Router
+protocol=MySQLClient
+port=4006
+
+[CLI]
+type=service
+router=cli
+
+[CLI Listener]
+type=listener
+service=CLI
+protocol=maxscaled
+socket=default

maxscale-system-test/config_test.cpp

@@ -20,6 +20,7 @@ const char *bad_configs[] =
     "mxs720_line_with_no_equal",
     "mxs720_wierd_line",
     "mxs799",
+    "mxs1731_empty_param",
     NULL
 };
 

maxscale-system-test/testconnections.cpp

@@ -1911,8 +1911,8 @@ bool TestConnections::test_bad_config(int m, const char *config)
     // Set the timeout to prevent hangs with configurations that work
     set_timeout(20);
 
-    return maxscales->ssh_node(m, "cp maxscale.cnf /etc/maxscale.cnf; service maxscale stop; "
-                               "maxscale -U maxscale -lstdout &> /dev/null && sleep 1 && pkill -9 maxscale", false) == 0;
+    return maxscales->ssh_node_f(m, true, "cp maxscale.cnf /etc/maxscale.cnf; service maxscale stop; "
+                                 "maxscale -U maxscale -lstdout &> /dev/null && sleep 1 && pkill -9 maxscale") == 0;
 }
 
 std::string dump_status(const StringSet& current, const StringSet& expected)

server/core/config.cc

@@ -463,6 +463,19 @@ void fix_section_name(char *section)
     replace_whitespace(section);
 }
 
+static bool is_empty_string(const char* str)
+{
+    for (const char* p = str; *p; p++)
+    {
+        if (!isspace(*p))
+        {
+            return false;
+        }
+    }
+
+    return true;
+}
+
 /**
  * Config item handler for the ini file reader
  *
@@ -477,6 +490,12 @@ static int ini_handler(void *userdata, const char *section, const char *name, co
     CONFIG_CONTEXT *cntxt = (CONFIG_CONTEXT *)userdata;
     CONFIG_CONTEXT *ptr = cntxt;
 
+    if (is_empty_string(value))
+    {
+        MXS_ERROR("Empty value given to parameter '%s'", name);
+        return 0;
+    }
+
     if (config_get_global_options()->substitute_variables)
     {
         if (*value == '$')