MXS-2304 Remove remaining uses of config_get_string() from module code

The function returns a pointer to an internal string and should not be
used.

include/maxscale/config.hh

@@ -231,15 +231,6 @@ public:
      */
     std::string get_string(const std::string& key) const;
 
-    /**
-     * Get value of key as c-string. The pointer is valid as long as the underlying configuration
-     * is not changed.
-     *
-     * @param key Parameter name
-     * @return Parameter value. Empty string if key not found.
-     */
-    const char* get_c_str(const std::string& key) const;
-
     /**
      * @brief Get copy of parameter value if it is defined
      *
@@ -431,16 +422,6 @@ bool config_param_is_valid(const MXS_MODULE_PARAM* params,
                            const char* value,
                            const CONFIG_CONTEXT* context);
 
-/**
- * @brief Get a string value
- *
- * @param params List of configuration parameters
- * @param key Parameter name
- *
- * @return The raw string value or an empty string if no parameter was found
- */
-const char* config_get_string(const MXS_CONFIG_PARAMETER* params, const char* key);
-
 /**
  * @brief Get an array of servers. The caller should free the produced array,
  * but not the array elements.

server/core/config.cc

@@ -1909,11 +1909,6 @@ bool config_get_compiled_regexes(const MXS_CONFIG_PARAMETER* params,
 }
 
 string MXS_CONFIG_PARAMETER::get_string(const std::string& key) const
-{
-    return get_c_str(key);
-}
-
-const char* MXS_CONFIG_PARAMETER::get_c_str(const std::string& key) const
 {
     return config_get_string(this, key.c_str());
 }

server/core/internal/config.hh

@@ -245,3 +245,13 @@ bool config_can_modify_at_runtime(const char* name);
  * @return The parameter or NULL if the parameter was not found
  */
 MXS_CONFIG_PARAMETER* config_get_param(MXS_CONFIG_PARAMETER* params, const char* name);
+
+/**
+ * @brief Get a string value
+ *
+ * @param params List of configuration parameters
+ * @param key Parameter name
+ *
+ * @return The raw string value or an empty string if no parameter was found
+ */
+const char* config_get_string(const MXS_CONFIG_PARAMETER* params, const char* key);

server/modules/filter/namedserverfilter/namedserverfilter.cc

@@ -250,9 +250,9 @@ RegexHintFilter* RegexHintFilter::create(const char* name, MXS_CONFIG_PARAMETER*
     SourceHostVector source_addresses;
     StringVector source_hostnames;
 
-    const char* source = config_get_string(params, "source");
+    std::string source = params->get_string("source");
 
-    if (*source)
+    if (!source.empty())
     {
         set_source_addresses(source, source_addresses, source_hostnames);
     }

server/modules/filter/regexfilter/regexfilter.cc

@@ -212,13 +212,13 @@ static MXS_FILTER* createInstance(const char* name, MXS_CONFIG_PARAMETER* params
         my_instance->user = params->get_c_str_copy("user");
         my_instance->log_trace = params->get_bool("log_trace");
 
-        const char* logfile = config_get_string(params, "log_file");
+        std::string logfile = params->get_string("log_file");
 
-        if (*logfile)
+        if (!logfile.empty())
         {
-            if ((my_instance->logfile = fopen(logfile, "a")) == NULL)
+            if ((my_instance->logfile = fopen(logfile.c_str(), "a")) == NULL)
             {
-                MXS_ERROR("Failed to open file '%s'.", logfile);
+                MXS_ERROR("Failed to open file '%s'.", logfile.c_str());
                 free_instance(my_instance);
                 return NULL;
             }

server/modules/filter/tee/tee.cc

@@ -65,21 +65,17 @@ Tee::Tee(SERVICE* service,
 Tee* Tee::create(const char* name, MXS_CONFIG_PARAMETER* params)
 {
     SERVICE* service = params->get_service("service");
-    const char* source = config_get_string(params, "source");
-    const char* user = config_get_string(params, "user");
     uint32_t cflags = params->get_enum("options", option_values);
     pcre2_code* match = config_get_compiled_regex(params, "match", cflags, NULL);
     pcre2_code* exclude = config_get_compiled_regex(params, "exclude", cflags, NULL);
-    const char* match_str = config_get_string(params, "match");
-    const char* exclude_str = config_get_string(params, "exclude");
 
     Tee* my_instance = new(std::nothrow) Tee(service,
-                                             source,
-                                             user,
+                                             params->get_string("source"),
+                                             params->get_string("user"),
                                              match,
-                                             match_str,
+                                             params->get_string("match"),
                                              exclude,
-                                             exclude_str);
+                                             params->get_string("exclude"));
 
     if (my_instance == NULL)
     {

server/modules/routing/readwritesplit/readwritesplit.cc

@@ -223,7 +223,7 @@ RWSplit* RWSplit::create(SERVICE* service, MXS_CONFIG_PARAMETER* params)
 
     Config config(params);
 
-    if (!handle_max_slaves(config, config_get_string(params, "max_slave_connections")))
+    if (!handle_max_slaves(config, params->get_string("max_slave_connections").c_str()))
     {
         return NULL;
     }
@@ -447,7 +447,7 @@ bool RWSplit::configure(MXS_CONFIG_PARAMETER* params)
     bool rval = false;
     Config cnf(params);
 
-    if (handle_max_slaves(cnf, config_get_string(params, "max_slave_connections")))
+    if (handle_max_slaves(cnf, params->get_string("max_slave_connections").c_str()))
     {
         m_config.assign(cnf);
         rval = true;