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[apple/xnu.git] / osfmk / mach / port.h

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 * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
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 * Please obtain a copy of the License at
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/*
 * @OSF_COPYRIGHT@
 */
/* 
 * Mach Operating System
 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 * NOTICE: This file was modified by McAfee Research in 2004 to introduce
 * support for mandatory and extensible security protections.  This notice
 * is included in support of clause 2.2 (b) of the Apple Public License,
 * Version 2.0.
 */
/*
 */
/*
 *	File:	mach/port.h
 *
 *	Definition of a Mach port
 *
 *	Mach ports are the endpoints to Mach-implemented communications
 *	channels (usually uni-directional message queues, but other types
 *	also exist).
 *
 *	Unique collections of these endpoints are maintained for each
 *	Mach task.  Each Mach port in the task's collection is given a 
 *	[task-local] name to identify it - and the the various "rights"
 *	held by the task for that specific endpoint.
 *
 *	This header defines the types used to identify these Mach ports
 *	and the various rights associated with them.  For more info see:
 *
 *	<mach/mach_port.h> - manipulation of port rights in a given space
 *	<mach/message.h> - message queue [and port right passing] mechanism
 *
 */

#ifndef	_MACH_PORT_H_
#define _MACH_PORT_H_

#include <sys/cdefs.h>
#include <stdint.h>
#include <mach/boolean.h>
#include <mach/machine/vm_types.h>

/*
 *	mach_port_name_t - the local identity for a Mach port
 *
 *	The name is Mach port namespace specific.  It is used to
 *	identify the rights held for that port by the task whose
 *	namespace is implied [or specifically provided].
 *
 *	Use of this type usually implies just a name - no rights.
 *	See mach_port_t for a type that implies a "named right."
 *
 */
 
typedef natural_t mach_port_name_t;
typedef mach_port_name_t *mach_port_name_array_t;

#ifdef	KERNEL

/* 
 *	mach_port_t - a named port right
 *
 *	In the kernel, "rights" are represented [named] by pointers to
 *	the ipc port object in question. There is no port namespace for the
 *	rights to be collected.
 *
 *	Actually, there is namespace for the kernel task.  But most kernel
 *	code - including, but not limited to, Mach IPC code - lives in the
 *	limbo between the current user-level task and the "next" task. Very
 *	little of the kernel code runs in full kernel task context.  So very
 *	little of it gets to use the kernel task's port name space.  
 *
 *	Because of this implementation approach, all in-kernel rights for
 *	a given port coalesce [have the same name/pointer].  The actual
 *	references are counted in the port itself.  It is up to the kernel
 *	code in question to "just remember" how many [and what type of]
 *	rights it holds and handle them appropriately.
 *
 */

#ifndef	MACH_KERNEL_PRIVATE
/*
 *	For kernel code that resides outside of Mach proper, we opaque the
 *	port structure definition.
 */
struct ipc_port ;

#endif	/* MACH_KERNEL_PRIVATE */

typedef struct ipc_port	        *ipc_port_t;

#define IPC_PORT_NULL		((ipc_port_t) 0UL)
#define IPC_PORT_DEAD		((ipc_port_t)~0UL)
#define IPC_PORT_VALID(port) \
	((port) != IPC_PORT_NULL && (port) != IPC_PORT_DEAD)

typedef ipc_port_t 		mach_port_t;

/*
 * Since the 32-bit and 64-bit representations of ~0 are different,
 * explicitly handle MACH_PORT_DEAD
 */

#define CAST_MACH_PORT_TO_NAME(x) ((mach_port_name_t)(uintptr_t)(x))
#define CAST_MACH_NAME_TO_PORT(x) ((x) == MACH_PORT_DEAD ? (mach_port_t)IPC_PORT_DEAD : (mach_port_t)(uintptr_t)(x))

#else	/* KERNEL */

/* 
 *	mach_port_t - a named port right
 *
 *	In user-space, "rights" are represented by the name of the
 *	right in the Mach port namespace.  Even so, this type is
 *	presented as a unique one to more clearly denote the presence
 *	of a right coming along with the name. 
 *
 *	Often, various rights for a port held in a single name space
 *	will coalesce and are, therefore, be identified by a single name
 *	[this is the case for send and receive rights].  But not
 *	always [send-once rights currently get a unique name for
 *	each right].      
 *
 */

#include <sys/_types.h>
#include <sys/_types/_mach_port_t.h>

#endif	/* KERNEL */

typedef mach_port_t			*mach_port_array_t;

/*
 *  MACH_PORT_NULL is a legal value that can be carried in messages.
 *  It indicates the absence of any port or port rights.  (A port
 *  argument keeps the message from being "simple", even if the
 *  value is MACH_PORT_NULL.)  The value MACH_PORT_DEAD is also a legal
 *  value that can be carried in messages.  It indicates
 *  that a port right was present, but it died.
 */

#define MACH_PORT_NULL		0  /* intentional loose typing */
#define MACH_PORT_DEAD		((mach_port_name_t) ~0)
#define MACH_PORT_VALID(name)				\
		(((name) != MACH_PORT_NULL) && 		\
		 ((name) != MACH_PORT_DEAD))


/*
 *	For kernel-selected [assigned] port names, the name is
 *	comprised of two parts: a generation number and an index.
 *	This approach keeps the exact same name from being generated
 *	and reused too quickly [to catch right/reference counting bugs].
 *	The dividing line between the constituent parts is exposed so
 *	that efficient "mach_port_name_t to data structure pointer"
 *	conversion implementation can be made.  But it is possible
 *	for user-level code to assign their own names to Mach ports.
 *	These are not required to participate in this algorithm.  So
 *	care should be taken before "assuming" this model.
 *
 */

#ifndef	NO_PORT_GEN

#define	MACH_PORT_INDEX(name)		((name) >> 8)
#define	MACH_PORT_GEN(name)		(((name) & 0xff) << 24)
#define	MACH_PORT_MAKE(index, gen)	\
		(((index) << 8) | (gen) >> 24)

#else	/* NO_PORT_GEN */

#define	MACH_PORT_INDEX(name)		(name)
#define	MACH_PORT_GEN(name)		(0)
#define	MACH_PORT_MAKE(index, gen)	(index)

#endif	/* NO_PORT_GEN */


/*
 *  These are the different rights a task may have for a port.
 *  The MACH_PORT_RIGHT_* definitions are used as arguments
 *  to mach_port_allocate, mach_port_get_refs, etc, to specify
 *  a particular right to act upon.  The mach_port_names and
 *  mach_port_type calls return bitmasks using the MACH_PORT_TYPE_*
 *  definitions.  This is because a single name may denote
 *  multiple rights.
 */

typedef natural_t mach_port_right_t;

#define MACH_PORT_RIGHT_SEND		((mach_port_right_t) 0)
#define MACH_PORT_RIGHT_RECEIVE		((mach_port_right_t) 1)
#define MACH_PORT_RIGHT_SEND_ONCE	((mach_port_right_t) 2)
#define MACH_PORT_RIGHT_PORT_SET	((mach_port_right_t) 3)
#define MACH_PORT_RIGHT_DEAD_NAME	((mach_port_right_t) 4)
#define MACH_PORT_RIGHT_LABELH	        ((mach_port_right_t) 5)
#define MACH_PORT_RIGHT_NUMBER		((mach_port_right_t) 6)

typedef natural_t mach_port_type_t;
typedef mach_port_type_t *mach_port_type_array_t;

#define MACH_PORT_TYPE(right)						\
		((mach_port_type_t)(((mach_port_type_t) 1)  		\
		<< ((right) + ((mach_port_right_t) 16))))	
#define MACH_PORT_TYPE_NONE	    ((mach_port_type_t) 0L)
#define MACH_PORT_TYPE_SEND	    MACH_PORT_TYPE(MACH_PORT_RIGHT_SEND)
#define MACH_PORT_TYPE_RECEIVE	    MACH_PORT_TYPE(MACH_PORT_RIGHT_RECEIVE)
#define MACH_PORT_TYPE_SEND_ONCE    MACH_PORT_TYPE(MACH_PORT_RIGHT_SEND_ONCE)
#define MACH_PORT_TYPE_PORT_SET	    MACH_PORT_TYPE(MACH_PORT_RIGHT_PORT_SET)
#define MACH_PORT_TYPE_DEAD_NAME    MACH_PORT_TYPE(MACH_PORT_RIGHT_DEAD_NAME)
#define MACH_PORT_TYPE_LABELH       MACH_PORT_TYPE(MACH_PORT_RIGHT_LABELH)

/* Convenient combinations. */

#define MACH_PORT_TYPE_SEND_RECEIVE					\
		(MACH_PORT_TYPE_SEND|MACH_PORT_TYPE_RECEIVE)
#define	MACH_PORT_TYPE_SEND_RIGHTS					\
		(MACH_PORT_TYPE_SEND|MACH_PORT_TYPE_SEND_ONCE)
#define	MACH_PORT_TYPE_PORT_RIGHTS					\
		(MACH_PORT_TYPE_SEND_RIGHTS|MACH_PORT_TYPE_RECEIVE)
#define	MACH_PORT_TYPE_PORT_OR_DEAD					\
		(MACH_PORT_TYPE_PORT_RIGHTS|MACH_PORT_TYPE_DEAD_NAME)
#define MACH_PORT_TYPE_ALL_RIGHTS					\
		(MACH_PORT_TYPE_PORT_OR_DEAD|MACH_PORT_TYPE_PORT_SET)

/* Dummy type bits that mach_port_type/mach_port_names can return. */

#define MACH_PORT_TYPE_DNREQUEST		0x80000000
#define MACH_PORT_TYPE_SPREQUEST		0x40000000
#define MACH_PORT_TYPE_SPREQUEST_DELAYED	0x20000000

/* User-references for capabilities. */

typedef natural_t mach_port_urefs_t;
typedef integer_t mach_port_delta_t;			/* change in urefs */

/* Attributes of ports.  (See mach_port_get_receive_status.) */

typedef natural_t mach_port_seqno_t;		/* sequence number */
typedef natural_t mach_port_mscount_t;		/* make-send count */
typedef natural_t mach_port_msgcount_t;		/* number of msgs */
typedef natural_t mach_port_rights_t;		/* number of rights */

/*
 *	Are there outstanding send rights for a given port?
 */
#define	MACH_PORT_SRIGHTS_NONE		0		/* no srights */
#define	MACH_PORT_SRIGHTS_PRESENT	1		/* srights */
typedef unsigned int mach_port_srights_t;	/* status of send rights */

typedef struct mach_port_status {
	mach_port_rights_t	mps_pset;	/* count of containing port sets */
	mach_port_seqno_t	mps_seqno;	/* sequence number */
	mach_port_mscount_t	mps_mscount;	/* make-send count */
	mach_port_msgcount_t	mps_qlimit;	/* queue limit */
	mach_port_msgcount_t	mps_msgcount;	/* number in the queue */
	mach_port_rights_t	mps_sorights;	/* how many send-once rights */
	boolean_t		mps_srights;	/* do send rights exist? */
	boolean_t		mps_pdrequest;	/* port-deleted requested? */
	boolean_t		mps_nsrequest;	/* no-senders requested? */
	natural_t		mps_flags;		/* port flags */
} mach_port_status_t;

/* System-wide values for setting queue limits on a port */
#define MACH_PORT_QLIMIT_ZERO		((mach_port_msgcount_t) 0)
#define MACH_PORT_QLIMIT_BASIC		((mach_port_msgcount_t) 5)
#define MACH_PORT_QLIMIT_SMALL		((mach_port_msgcount_t) 16)
#define MACH_PORT_QLIMIT_LARGE		((mach_port_msgcount_t) 1024)
#define MACH_PORT_QLIMIT_KERNEL		((mach_port_msgcount_t) 65536)
#define MACH_PORT_QLIMIT_MIN		MACH_PORT_QLIMIT_ZERO
#define MACH_PORT_QLIMIT_DEFAULT	MACH_PORT_QLIMIT_BASIC
#define MACH_PORT_QLIMIT_MAX		MACH_PORT_QLIMIT_LARGE

typedef struct mach_port_limits {
	mach_port_msgcount_t	mpl_qlimit;	/* number of msgs */
} mach_port_limits_t;

/* Possible values for mps_flags (part of mach_port_status_t) */
#define MACH_PORT_STATUS_FLAG_TEMPOWNER		0x01
#define MACH_PORT_STATUS_FLAG_GUARDED		0x02
#define MACH_PORT_STATUS_FLAG_STRICT_GUARD	0x04
#define MACH_PORT_STATUS_FLAG_IMP_DONATION	0x08
#define MACH_PORT_STATUS_FLAG_REVIVE		0x10
#define MACH_PORT_STATUS_FLAG_TASKPTR		0x20

typedef struct mach_port_info_ext {
	mach_port_status_t	mpie_status;
	mach_port_msgcount_t	mpie_boost_cnt;
	uint32_t		reserved[6];
} mach_port_info_ext_t;

typedef integer_t *mach_port_info_t;		/* varying array of natural_t */

/* Flavors for mach_port_get/set_attributes() */
typedef int	mach_port_flavor_t;
#define MACH_PORT_LIMITS_INFO		1	/* uses mach_port_status_t */
#define MACH_PORT_RECEIVE_STATUS	2	/* uses mach_port_limits_t */
#define MACH_PORT_DNREQUESTS_SIZE	3	/* info is int */
#define MACH_PORT_TEMPOWNER		4	/* indicates receive right will be reassigned to another task */
#define MACH_PORT_IMPORTANCE_RECEIVER	5	/* indicates recieve right accepts priority donation */
#define MACH_PORT_INFO_EXT		7	/* uses mach_port_info_ext_t */

#define MACH_PORT_LIMITS_INFO_COUNT	((natural_t) \
	(sizeof(mach_port_limits_t)/sizeof(natural_t)))
#define MACH_PORT_RECEIVE_STATUS_COUNT	((natural_t) \
	(sizeof(mach_port_status_t)/sizeof(natural_t)))
#define MACH_PORT_DNREQUESTS_SIZE_COUNT 1
#define MACH_PORT_INFO_EXT_COUNT	((natural_t) \
	(sizeof(mach_port_info_ext_t)/sizeof(natural_t)))
/*
 * Structure used to pass information about port allocation requests.
 * Must be padded to 64-bits total length.
 */
typedef struct mach_port_qos {
	unsigned int		name:1;		/* name given */
	unsigned int 		prealloc:1;	/* prealloced message */
	boolean_t		pad1:30;
	natural_t		len;
} mach_port_qos_t;

/* Mach Port Guarding definitions */

/*
 * Flags for mach_port_options (used for
 * invocation of mach_port_construct).
 * Indicates attributes to be set for the newly
 * allocated port.
 */
#define MPO_CONTEXT_AS_GUARD	0x01	/* Add guard to the port */
#define MPO_QLIMIT		0x02	/* Set qlimit for the port msg queue */
#define MPO_TEMPOWNER		0x04	/* Set the tempowner bit of the port */
#define MPO_IMPORTANCE_RECEIVER 0x08	/* Mark the port as importance receiver */
#define MPO_INSERT_SEND_RIGHT   0x10	/* Insert a send right for the port */
#define MPO_STRICT		0x20	/* Apply strict guarding for port */

/*
 * Structure to define optional attributes for a newly
 * constructed port.
 */
typedef struct mach_port_options {
	uint32_t		flags;		/* Flags defining attributes for port */
	mach_port_limits_t	mpl;		/* Message queue limit for port */
	uint64_t		reserved[2];	/* Reserved */
}mach_port_options_t;

typedef mach_port_options_t *mach_port_options_ptr_t;

/*
 * EXC_GUARD represents a guard violation for both
 * mach ports and file descriptors. GUARD_TYPE_ is used
 * to differentiate among them.
 */
#define GUARD_TYPE_MACH_PORT	0x1

/* Reasons for exception for a guarded mach port */
enum mach_port_guard_exception_codes {
	kGUARD_EXC_DESTROY		= 1u << 0,
	kGUARD_EXC_MOD_REFS		= 1u << 1,
	kGUARD_EXC_SET_CONTEXT		= 1u << 2,
	kGUARD_EXC_UNGUARDED		= 1u << 3,
	kGUARD_EXC_INCORRECT_GUARD	= 1u << 4
};

#if	!__DARWIN_UNIX03 && !defined(_NO_PORT_T_FROM_MACH)
/*
 *  Mach 3.0 renamed everything to have mach_ in front of it.
 *  These types and macros are provided for backward compatibility
 *	but are deprecated.
 */
typedef mach_port_t		port_t;
typedef mach_port_name_t	port_name_t;
typedef mach_port_name_t	*port_name_array_t;

#define PORT_NULL		((port_t) 0)
#define PORT_DEAD		((port_t) ~0)
#define PORT_VALID(name) \
		((port_t)(name) != PORT_NULL && (port_t)(name) != PORT_DEAD)

#endif	/* !__DARWIN_UNIX03 && !_NO_PORT_T_FROM_MACH */

#endif	/* _MACH_PORT_H_ */