From 7e353883367927b653b0243a1b3737d9f498a122 Mon Sep 17 00:00:00 2001
From: Norman Feske <norman.feske@genode-labs.com>
Date: Sun, 8 Sep 2013 16:19:38 +0200
Subject: [PATCH] os: Skeleton for server implementations

---
 os/include/os/server.h      |  82 +++++++++++++++++++++++
 os/lib/mk/server.mk         |   3 +
 os/src/lib/server/server.cc | 125 ++++++++++++++++++++++++++++++++++++
 3 files changed, 210 insertions(+)
 create mode 100644 os/include/os/server.h
 create mode 100644 os/lib/mk/server.mk
 create mode 100644 os/src/lib/server/server.cc

diff --git a/os/include/os/server.h b/os/include/os/server.h
new file mode 100644
index 000000000..fe26bc2a9
--- /dev/null
+++ b/os/include/os/server.h
@@ -0,0 +1,82 @@
+/*
+ * \brief  Skeleton for implementing servers
+ * \author Norman Feske
+ * \date   2013-09-07
+ */
+
+/*
+ * Copyright (C) 2013 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+#ifndef _INCLUDE__OS__SERVER_H_
+#define _INCLUDE__OS__SERVER_H_
+
+#include <os/signal_rpc_dispatcher.h>
+
+namespace Server {
+
+	using namespace Genode;
+
+	class Entrypoint
+	{
+		private:
+
+			Rpc_entrypoint &_rpc_ep;
+
+		public:
+
+			Entrypoint();
+
+			/**
+			 * Associate RPC object with the entry point
+			 */
+			template <typename RPC_INTERFACE, typename RPC_SERVER>
+			Capability<RPC_INTERFACE>
+			manage(Rpc_object<RPC_INTERFACE, RPC_SERVER> &obj)
+			{
+				return _rpc_ep.manage(&obj);
+			}
+
+			/**
+			 * Dissolve RPC object from entry point
+			 */
+			template <typename RPC_INTERFACE, typename RPC_SERVER>
+			void dissolve(Rpc_object<RPC_INTERFACE, RPC_SERVER> &obj)
+			{
+				_rpc_ep.dissolve(&obj);
+			}
+
+			/**
+			 * Associate signal dispatcher with entry point
+			 */
+			Signal_context_capability manage(Signal_rpc_dispatcher_base &);
+
+			/**
+			 * Disassociate signal dispatcher from entry point
+			 */
+			void dissolve(Signal_rpc_dispatcher_base &);
+
+			/**
+			 * Return RPC entrypoint
+			 */
+			Rpc_entrypoint &rpc_ep() { return _rpc_ep; }
+	};
+
+	void wait_and_dispatch_one_signal();
+
+
+	/***********************************************************
+	 ** Functions to be provided by the server implementation **
+	 ***********************************************************/
+
+	size_t stack_size();
+
+	char const *name();
+
+	void construct(Entrypoint &);
+};
+
+#endif /* _INCLUDE__OS__SERVER_H_ */
diff --git a/os/lib/mk/server.mk b/os/lib/mk/server.mk
new file mode 100644
index 000000000..89472ab84
--- /dev/null
+++ b/os/lib/mk/server.mk
@@ -0,0 +1,3 @@
+SRC_CC = server.cc
+
+vpath server.cc $(REP_DIR)/src/lib/server
diff --git a/os/src/lib/server/server.cc b/os/src/lib/server/server.cc
new file mode 100644
index 000000000..87a5d9478
--- /dev/null
+++ b/os/src/lib/server/server.cc
@@ -0,0 +1,125 @@
+/*
+ * \brief  Skeleton for implementing servers
+ * \author Norman Feske
+ * \date   2013-09-07
+ */
+
+/*
+ * Copyright (C) 2013 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+#include <os/server.h>
+#include <cap_session/connection.h>
+
+using namespace Server;
+
+
+static Cap_session &global_cap_session()
+{
+	static Cap_connection inst;
+	return inst;
+}
+
+
+static Rpc_entrypoint &global_rpc_ep()
+{
+	static Rpc_entrypoint inst(&global_cap_session(),
+	                           stack_size(),
+	                           name());
+	return inst;
+}
+
+
+static Entrypoint &global_ep()
+{
+	static Server::Entrypoint inst;
+	return inst;
+}
+
+
+static Genode::Signal_receiver &global_sig_rec()
+{
+	static Genode::Signal_receiver inst;
+	return inst;
+}
+
+
+Signal_context_capability Entrypoint::manage(Signal_rpc_dispatcher_base &dispatcher)
+{
+	return dispatcher.manage(global_sig_rec(), global_rpc_ep());
+}
+
+
+void Server::Entrypoint::dissolve(Signal_rpc_dispatcher_base &dispatcher)
+{
+	dispatcher.dissolve(global_sig_rec(), global_rpc_ep());
+}
+
+
+Server::Entrypoint::Entrypoint() : _rpc_ep(global_rpc_ep()) { }
+
+
+void Server::wait_and_dispatch_one_signal()
+{
+	/*
+	 * We call the signal dispatcher outside of the scope of 'Signal'
+	 * object because we block the RPC interface in the input handler
+	 * when the kill mode gets actived. While kill mode is active, we
+	 * do not serve incoming RPC requests but we need to stay responsive
+	 * to user input. Hence, we wait for signals in the input dispatcher
+	 * in this case. An already existing 'Signal' object would lock the
+	 * signal receiver and thereby prevent this nested way of signal
+	 * handling.
+	 */
+	Signal_dispatcher_base *dispatcher = 0;
+	unsigned num = 0;
+
+	{
+		Signal sig = global_sig_rec().wait_for_signal();
+		dispatcher = dynamic_cast<Signal_dispatcher_base *>(sig.context());
+		num        = sig.num();
+	}
+
+	if (dispatcher)
+		dispatcher->dispatch(num);
+}
+
+
+namespace Server {
+	struct Constructor;
+	struct Constructor_component;
+}
+
+
+struct Server::Constructor
+{
+	GENODE_RPC(Rpc_construct, void, construct);
+	GENODE_RPC_INTERFACE(Rpc_construct);
+};
+
+
+struct Server::Constructor_component : Rpc_object<Server::Constructor,
+                                                  Server::Constructor_component>
+{
+	void construct() { Server::construct(global_ep()); }
+};
+
+
+int main(int argc, char **argv)
+{
+	static Server::Constructor_component constructor;
+
+	static Server::Entrypoint ep;
+
+	/* call Server::construct in the context of the entrypoint */
+	Capability<Server::Constructor> constructor_cap = ep.manage(constructor);
+	
+	constructor_cap.call<Server::Constructor::Rpc_construct>();
+
+	/* process incoming signals */
+	for (;;)
+		Server::wait_and_dispatch_one_signal();
+}