/*
 * \brief  Native types
 * \author Norman Feske
 * \date   2007-10-15
 */

/*
 * Copyright (C) 2007-2013 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__BASE__NATIVE_TYPES_H_
#define _INCLUDE__BASE__NATIVE_TYPES_H_

#include <util/string.h>
#include <base/native_capability.h>
#include <base/stdint.h>

/*
 * We cannot just include <semaphore.h> and <pthread.h> here
 * because this would imply the nested inclusion of a myriad
 * of Linux types and would pollute the namespace for everyone
 * who includes this header file. We want to cleanly separate
 * Genode from POSIX.
 */

extern Genode::addr_t _stack_area_start;

namespace Genode {

	/**
	 * Thread ID
	 *
	 * Unfortunately, both - PID and TID - are needed for lx_tgkill()
	 */
	struct Native_thread_id
	{
		unsigned int tid;  /* Native thread ID type as returned by the
		                      'clone' system call */
		unsigned int pid;  /* process ID (resp. thread-group ID) */

		Native_thread_id() : tid(0), pid(0) { }
		Native_thread_id(unsigned int tid, unsigned int pid)
		: tid(tid), pid(pid) { }
	};

	struct Thread_meta_data;

	/**
	 * Native thread contains more thread-local data than just the ID
	 *
	 * FIXME doc
	 * A thread needs two sockets as it may be a server that depends on another
	 * service during request processing. If the server socket would be used for
	 * the client call, the server thread may be unblocked by further requests
	 * from its clients. In other words, the additional client socket provides
	 * closed-receive semantics in calls. An even better solution is to use
	 * SCM_RIGHTS messages to send a client socket descriptor with the request.
	 */
	struct Native_thread : Native_thread_id
	{
		bool is_ipc_server;

		/**
		 * Natively aligned memory location used in the lock implementation
		 */
		int futex_counter __attribute__((aligned(sizeof(Genode::addr_t))));

		/**
		 * Opaque pointer to additional thread-specific meta data
		 *
		 * This pointer is used by hybrid Linux/Genode program to maintain
		 * POSIX-thread-related meta data. For non-hybrid Genode programs, it
		 * remains unused.
		 */
		Thread_meta_data *meta_data;

		Native_thread() : is_ipc_server(false), futex_counter(0), meta_data(0) { }
	};

	inline bool operator == (Native_thread_id t1, Native_thread_id t2) {
		return (t1.tid == t2.tid) && (t1.pid == t2.pid); }

	inline bool operator != (Native_thread_id t1, Native_thread_id t2) {
		return (t1.tid != t2.tid) || (t1.pid != t2.pid); }

	struct Cap_dst_policy
	{
		struct Dst
		{
			int socket;

			/**
			 * Default constructor creates invalid destination
			 */
			Dst() : socket(-1) { }

			explicit Dst(int socket) : socket(socket) { }
		};

		static bool valid(Dst id) { return id.socket != -1; }
		static Dst  invalid()     { return Dst(); }
		static void copy(void* dst, Native_capability_tpl<Cap_dst_policy>* src);
	};

	/**
	 * Empty UTCB type expected by the thread library, unused on Linux
	 */
	typedef struct { } Native_utcb;

	typedef Native_capability_tpl<Cap_dst_policy> Native_capability;

	/**
	 * The connection state is the socket handle of the RPC entrypoint
	 */
	struct Native_connection_state
	{
		int server_sd;
		int client_sd;

		Native_connection_state() : server_sd(-1), client_sd(-1) { }
	};

	enum { PARENT_SOCKET_HANDLE = 100 };

	struct Native_config
	{
		/**
		 * Stack area configuration
		 *
		 * Please update platform-specific files after changing these
		 * functions, e.g., 'base-linux/src/ld/stack_area.*.ld'.
		 */
		static addr_t stack_area_virtual_base() {
			return align_addr((addr_t)&_stack_area_start, 20); }

		static constexpr addr_t stack_area_virtual_size() {
			return 0x10000000UL; }

		/**
		 * Size of virtual address region holding the stack of one thread
		 */
		static constexpr addr_t stack_virtual_size() { return 0x00100000UL; }
	};

	class Native_pd_args
	{
		public:

			enum { ROOT_PATH_MAX_LEN = 256 };

		private:

			char _root[ROOT_PATH_MAX_LEN];

			unsigned _uid;
			unsigned _gid;

		public:

			Native_pd_args() : _uid(0), _gid(0) { _root[0] = 0; }

			Native_pd_args(char const *root, unsigned uid, unsigned gid)
			:
				_uid(uid), _gid(gid)
			{
				Genode::strncpy(_root, root, sizeof(_root));
			}

			char const *root() const { return _root; }
			unsigned    uid()  const { return _uid;  }
			unsigned    gid()  const { return _gid;  }
	};
}

#endif /* _INCLUDE__BASE__NATIVE_TYPES_H_ */