Move loading of user data to authenticator modules

The authenticator modules now load the user data when the new loadusers
entry point is called. This new entry point is optional.

At the moment the code that was in service.c was just moved into the
modules but the ground work for allowing different user loading mechanisms
is done.

Further improvements need to be made so that the authenticators behave
more like routers and filters. This work includes the creation of a
AUTHENTICATOR module object, addition of createInstance entry points for
authenticators and implementing it for all authenticators.

server/include/gw_authenticator.h

@@ -36,6 +36,7 @@
 struct dcb;
 struct server;
 struct session;
+struct servlistener;
 
 /**
  * @verbatim
@@ -44,6 +45,8 @@ struct session;
  *      extract         Extract the data from a buffer and place in a structure
  *      connectssl      Determine whether the connection can support SSL
  *      authenticate    Carry out the authentication
+ *      free            Free extracted data
+ *      loadusers       Load or update authenticator user data
  * @endverbatim
  *
  * This forms the "module object" for authenticator modules within the gateway.
@@ -56,14 +59,19 @@ typedef struct gw_authenticator
     bool (*connectssl)(struct dcb *);
     int (*authenticate)(struct dcb *);
     void (*free)(struct dcb *);
+    int (*loadusers)(struct servlistener *);
 } GWAUTHENTICATOR;
 
+/** Return values for the loadusers entry point */
+#define AUTH_LOADUSERS_OK    0 /**< Users loaded successfully */
+#define AUTH_LOADUSERS_ERROR 1 /**< Failed to load users */
+
 /**
  * The GWAUTHENTICATOR version data. The following should be updated whenever
  * the GWAUTHENTICATOR structure is changed. See the rules defined in modinfo.h
  * that define how these numbers should change.
  */
-#define GWAUTHENTICATOR_VERSION      {1, 0, 0}
+#define GWAUTHENTICATOR_VERSION      {1, 1, 0}
 
 
 #endif /* GW_AUTHENTICATOR_H */