Addition of global Makefile

First example external module, testroute, has been added. This serves more as an example than a real router
Updated module loading to used fixed GetModuleObject route and addition of ModuleInit routine

Makefile

@@ -0,0 +1,27 @@
+# This file is distributed as part of the SkySQL Gateway.  It is free
+# software: you can redistribute it and/or modify it under the terms of the
+# GNU General Public License as published by the Free Software Foundation,
+# version 2.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc., 51
+# Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+# Copyright SkySQL Ab 2013
+#
+# Revision History
+# Date		Who			Description
+# 14/06/13	Mark Riddoch		Initial implementation
+
+all:
+	(cd core; make)
+	(cd modules/routing; make)
+
+clean:
+	(cd core; make clean)
+	(cd modules/routing; make clean)

core/gateway.c

@@ -179,6 +179,8 @@ int main(int argc, char **argv) {
 
 	fprintf(stderr, "(C) SkySQL Ab 2013\n"); 
 
+	load_module("testroute", "Router");
+
 	if (sigfillset(&sigset) != 0) {
 		fprintf(stderr, "sigfillset() error %s\n", strerror(errno));
 		return 1;

core/load_utils.c

@@ -24,6 +24,9 @@
  *
  * Date		Who		Description
  * 13/06/13	Mark Riddoch	Initial implementation
+ * 14/06/13	Mark Riddoch	Updated to add call to ModuleInit if one is defined
+ * 				in the loaded module.
+ * 				Also updated to call fixed GetModuleObject
  *
  */
 #include	<sys/param.h>
@@ -51,7 +54,7 @@ static void unregister_module(const char *module);
  * @return		The module specific entry point structure or NULL
  */
 void *
-load_module(const char *module, const char *type, const char *entry)
+load_module(const char *module, const char *type)
 {
 char	*home, *version;
 char	fname[MAXPATHLEN];
@@ -67,7 +70,7 @@ MODULES	*mod;
 		 *
 		 * Search of the shared object.
 		 */
-		sprintf(fname, "lib%s.so", module);
+		sprintf(fname, "./lib%s.so", module);
 		if (access(fname, F_OK) == -1)
 		{
 			if ((home = getenv("GATEWAY_HOME")) == NULL)
@@ -94,7 +97,16 @@ MODULES	*mod;
 		ver = sym;
 		version = ver();
 
-		if ((sym = dlsym(dlhandle, entry)) == NULL)
+		/*
+		 * If the module has a ModuleInit function cal it now.
+		 */
+		if ((sym = dlsym(dlhandle, "ModuleInit")) != NULL)
+		{
+			void (*ModuleInit)() = sym;
+			ModuleInit();
+		}
+
+		if ((sym = dlsym(dlhandle, "GetModuleObject")) == NULL)
 		{
 			fprintf(stderr, "Expected entry point interface missing from module: %s, %s\n", module, dlerror());
 			dlclose(dlhandle);

include/modules.h

@@ -38,7 +38,7 @@ typedef struct modules {
 		*next;		/* Next module in the linked list */
 } MODULES;
 
-extern	void 	*load_module(const char *module, const char *type, const char *entry);
+extern	void 	*load_module(const char *module, const char *type);
 extern	void	unload_module(const char *module);
 extern	void	printModules();
 #endif

include/router.h

@@ -0,0 +1,59 @@
+#ifndef _ROUTER_H
+#define _ROUTER_H
+/*
+ * This file is distributed as part of the SkySQL Gateway.  It is free
+ * software: you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation,
+ * version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright SkySQL Ab 2013
+ */
+
+/*
+ * The query router interface mechanisms
+ *
+ * Revision History
+ *
+ * Date		Who		Description
+ * 14/06/13	Mark Riddoch	Initial implementation
+ *
+ */
+#include <service.h>
+#include <session.h>
+#include <buffer.h>
+
+/*
+ * the ROUTER handle points to module specific data, so the best we can do
+ * is to make it a void * externally.
+ */
+typedef void *ROUTER;
+
+
+/*
+ * The "module object" structure for a query router module
+ *
+ * The entry points are:
+ * 	createInstance		Called by the service to create a new
+ * 				instance of the query router
+ * 	newSession		Called to create a new user session
+ * 				within the query router
+ * 	closeSession		Called when a session is closed
+ * 	routeQuery		Called on each query that requires
+ * 				routing
+ */
+typedef struct {
+	ROUTER	*(*createInstance)(SERVICE *service);
+	void	*(*newSession)(ROUTER *instance, SESSION *session);
+	void 	(*closeSession)(ROUTER *instance, SESSION *session);
+	int	(*routeQuery)(ROUTER *instance, SESSION *session, GWBUF *queue);
+} ROUTER_OBJECT;
+#endif

include/service.h

@@ -0,0 +1,52 @@
+#ifndef _SERVICE_H
+#define _SERVICE_H
+/*
+ * This file is distributed as part of the SkySQL Gateway.  It is free
+ * software: you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation,
+ * version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright SkySQL Ab 2013
+ */
+
+/*
+ * The service level definitions within the gateway
+ *
+ * Revision History
+ *
+ * Date		Who		Description
+ * 14/06/13	Mark Riddoch	Initial implementation
+ *
+ */
+struct	server;
+struct	router;
+
+typedef struct servprotocol {
+	char		*protocol;	/* Protocol name */
+	int		port;		/* Port to listen on */
+	char		*routerModule;	/* Name of router module to use */
+	struct router	*router;
+	struct	servprotocol
+			*next;		/* Next service protocol */
+} SERV_PROTOCOL;
+
+typedef struct service {
+	char		*name;		/* The service name */
+	SERV_PROTOCOL	*ports;		/* Linked list of ports and protocols
+					 * that this service will listen on.
+					 */
+	struct server	*servers;	/* Linked list of databases associated
+					 * with this service
+					 */
+} SERVICE;
+
+#endif

modules/routing/Makefile

@@ -0,0 +1,38 @@
+# This file is distributed as part of the SkySQL Gateway.  It is free
+# software: you can redistribute it and/or modify it under the terms of the
+# GNU General Public License as published by the Free Software Foundation,
+# version 2.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc., 51
+# Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+# Copyright SkySQL Ab 2013
+#
+# Revision History
+# Date		Who			Description
+# 13/06/13	Mark Riddoch		Initial routing module development
+
+CC=cc
+CFLAGS=-c -fPIC -I/usr/include -I../include -I../../include
+LDFLAGS=-shared
+SRCS=testroute.c
+OBJ=$(SRCS:.c=.o)
+LIBS=-lssl
+
+libtestroute.so: $(OBJ)
+	$(CC) $(LDFLAGS) $(OBJ) $(LIBS) -o $@
+
+.c.o:
+	$(CC) $(CFLAGS) $< -o $@
+
+clean:
+	rm -f $(OBJ) libtestroute.so
+
+tags:
+	ctags $(SRCS) $(HDRS)

modules/routing/testroute.c

@@ -0,0 +1,107 @@
+/*
+ * This file is distributed as part of the SkySQL Gateway.  It is free
+ * software: you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation,
+ * version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright SkySQL Ab 2013
+ */
+#include <stdio.h>
+#include <router.h>
+
+static char *version_str = "V1.0.0";
+
+static	ROUTER	*createInstance(SERVICE *service);
+static	void	*newSession(ROUTER *instance, SESSION *session);
+static	void 	closeSession(ROUTER *instance, SESSION *session);
+static	int	routeQuery(ROUTER *instance, SESSION *session, GWBUF *queue);
+
+static ROUTER_OBJECT MyObject = { createInstance, newSession, closeSession, routeQuery };
+
+/*
+ * Implementation of the mandatory version entry point
+ *
+ * @return version string of the module
+ */
+char *
+version()
+{
+	return version_str;
+}
+
+/*
+ * The module initialisation routine, called when the module
+ * is first loaded.
+ */
+void
+ModuleInit()
+{
+	fprintf(stderr, "Initial test router module.\n");
+}
+
+/*
+ * The module entry point routine. It is this routine that
+ * must populate the structure that is referred to as the
+ * "module object", this is a structure with the set of
+ * external entry points for this module.
+ *
+ * @return The module object
+ */
+ROUTER_OBJECT *
+GetModuleObject()
+{
+	fprintf(stderr, "Returing test router module object.\n");
+	return &MyObject;
+}
+
+/*
+ * Create an instance of the router for a particular service
+ * within the gateway.
+ * 
+ * @param service	The service this router is being create for
+ *
+ * @return The instance data for this new instance
+ */
+static	ROUTER	*
+createInstance(SERVICE *service)
+{
+}
+
+/*
+ * Associate a new session with this instance of the router.
+ *
+ * @param instance	The router instance data
+ * @param session	The session itself
+ * @return Session specific data for this session
+ */
+static	void	*
+newSession(ROUTER *instance, SESSION *session)
+{
+}
+
+/*
+ * Close a session with the router, this is the mechanism
+ * by which a router may cleanup data structure etc.
+ *
+ * @param instance	The router instance data
+ * @param session	The session being closed
+ */
+static	void 	
+closeSession(ROUTER *instance, SESSION *session)
+{
+}
+
+
+static	int	
+routeQuery(ROUTER *instance, SESSION *session, GWBUF *queue)
+{
+}