[apple/xnu.git] / bsd / sys / lock.h

/*
 * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */
/* 
 * Copyright (c) 1995
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code contains ideas from software contributed to Berkeley by
 * Avadis Tevanian, Jr., Michael Wayne Young, and the Mach Operating
 * System project at Carnegie-Mellon University.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)lock.h	8.12 (Berkeley) 5/19/95
 */

#ifndef	_SYS_LOCK_H_
#define	_SYS_LOCK_H_

#include <sys/appleapiopts.h>

#ifdef KERNEL
#ifdef __APPLE_API_UNSTABLE
#include <kern/simple_lock.h>
#include <kern/simple_lock_types.h>

#if defined(simple_lock_init)
#undef simple_lock_init
#endif
#define simple_lock_init(l)	usimple_lock_init((l),0)

#if defined(simple_lock)
#undef simple_lock
#endif
#define simple_lock(l)         ((void) 1)

#if defined(simple_unlock)
#undef simple_unlock
#endif
#define simple_unlock(l)        ((void) 1)

#if defined(simple_lock_try)
#undef simple_lock_try
#endif
#define simple_lock_try(l)      1

#if defined(thread_sleep_simple_lock)
#undef thread_sleep_simple_lock
#endif
#define thread_sleep_simple_lock(l, e, i) thread_sleep_funnel((e), (i))

#endif /* __APPLE_API_UNSTABLE */
#else /* KERNEL */

#ifndef	_MACHINE_SIMPLE_LOCK_DATA_
#define	_MACHINE_SIMPLE_LOCK_DATA_

#include <mach/boolean.h>

struct slock{
	volatile unsigned int lock_data[10];
};
typedef struct slock	simple_lock_data_t;
typedef struct slock	*simple_lock_t;
#define	decl_simple_lock_data(class,name) \
class	simple_lock_data_t	name;

#endif	/* _MACHINE_SIMPLE_LOCK_DATA_ */

#endif /* KERNEL */

#ifdef __APPLE_API_UNSTABLE
/*
 * The general lock structure.  Provides for multiple shared locks,
 * upgrading from shared to exclusive, and sleeping until the lock
 * can be gained. The simple locks are defined in <machine/param.h>.
 */
struct lock__bsd__ {
	simple_lock_data_t
		lk_interlock;		/* lock on remaining fields */
	u_int	lk_flags;		/* see below */
	int	lk_sharecount;		/* # of accepted shared locks */
	int	lk_waitcount;		/* # of processes sleeping for lock */
	short	lk_exclusivecount;	/* # of recursive exclusive locks */
	short	lk_prio;		/* priority at which to sleep */
	char	*lk_wmesg;		/* resource sleeping (for tsleep) */
	int	lk_timo;		/* maximum sleep time (for tsleep) */
	pid_t	lk_lockholder;		/* pid of exclusive lock holder */
	void	*lk_lockthread;		/* thread which acquired excl lock */
};
/*
 * Lock request types:
 *   LK_SHARED - get one of many possible shared locks. If a process
 *	holding an exclusive lock requests a shared lock, the exclusive
 *	lock(s) will be downgraded to shared locks.
 *   LK_EXCLUSIVE - stop further shared locks, when they are cleared,
 *	grant a pending upgrade if it exists, then grant an exclusive
 *	lock. Only one exclusive lock may exist at a time, except that
 *	a process holding an exclusive lock may get additional exclusive
 *	locks if it explicitly sets the LK_CANRECURSE flag in the lock
 *	request, or if the LK_CANRECUSE flag was set when the lock was
 *	initialized.
 *   LK_UPGRADE - the process must hold a shared lock that it wants to
 *	have upgraded to an exclusive lock. Other processes may get
 *	exclusive access to the resource between the time that the upgrade
 *	is requested and the time that it is granted.
 *   LK_EXCLUPGRADE - the process must hold a shared lock that it wants to
 *	have upgraded to an exclusive lock. If the request succeeds, no
 *	other processes will have gotten exclusive access to the resource
 *	between the time that the upgrade is requested and the time that
 *	it is granted. However, if another process has already requested
 *	an upgrade, the request will fail (see error returns below).
 *   LK_DOWNGRADE - the process must hold an exclusive lock that it wants
 *	to have downgraded to a shared lock. If the process holds multiple
 *	(recursive) exclusive locks, they will all be downgraded to shared
 *	locks.
 *   LK_RELEASE - release one instance of a lock.
 *   LK_DRAIN - wait for all activity on the lock to end, then mark it
 *	decommissioned. This feature is used before freeing a lock that
 *	is part of a piece of memory that is about to be freed.
 *
 * These are flags that are passed to the lockmgr routine.
 */
#define LK_TYPE_MASK	0x0000000f	/* type of lock sought */
#define LK_SHARED	0x00000001	/* shared lock */
#define LK_EXCLUSIVE	0x00000002	/* exclusive lock */
#define LK_UPGRADE	0x00000003	/* shared-to-exclusive upgrade */
#define LK_EXCLUPGRADE	0x00000004	/* first shared-to-exclusive upgrade */
#define LK_DOWNGRADE	0x00000005	/* exclusive-to-shared downgrade */
#define LK_RELEASE	0x00000006	/* release any type of lock */
#define LK_DRAIN	0x00000007	/* wait for all lock activity to end */
/*
 * External lock flags.
 *
 * The first three flags may be set in lock_init to set their mode permanently,
 * or passed in as arguments to the lock manager. The LK_REENABLE flag may be
 * set only at the release of a lock obtained by drain.
 */
#define LK_EXTFLG_MASK	0x00000070	/* mask of external flags */
#define LK_NOWAIT	0x00000010	/* do not sleep to await lock */
#define LK_SLEEPFAIL	0x00000020	/* sleep, then return failure */
#define LK_CANRECURSE	0x00000040	/* allow recursive exclusive lock */
#define LK_REENABLE	0x00000080	/* lock is be reenabled after drain */
/*
 * Internal lock flags.
 *
 * These flags are used internally to the lock manager.
 */
#define LK_WANT_UPGRADE	0x00000100	/* waiting for share-to-excl upgrade */
#define LK_WANT_EXCL	0x00000200	/* exclusive lock sought */
#define LK_HAVE_EXCL	0x00000400	/* exclusive lock obtained */
#define LK_WAITDRAIN	0x00000800	/* process waiting for lock to drain */
#define LK_DRAINING	0x00004000	/* lock is being drained */
#define LK_DRAINED	0x00008000	/* lock has been decommissioned */
/*
 * Control flags
 *
 * Non-persistent external flags.
 */
#define LK_INTERLOCK	0x00010000	/* unlock passed simple lock after
					   getting lk_interlock */
#define LK_RETRY	0x00020000	/* vn_lock: retry until locked */

/*
 * Lock return status.
 *
 * Successfully obtained locks return 0. Locks will always succeed
 * unless one of the following is true:
 *	LK_FORCEUPGRADE is requested and some other process has already
 *	    requested a lock upgrade (returns EBUSY).
 *	LK_WAIT is set and a sleep would be required (returns EBUSY).
 *	LK_SLEEPFAIL is set and a sleep was done (returns ENOLCK).
 *	PCATCH is set in lock priority and a signal arrives (returns
 *	    either EINTR or ERESTART if system calls is to be restarted).
 *	Non-null lock timeout and timeout expires (returns EWOULDBLOCK).
 * A failed lock attempt always returns a non-zero error value. No lock
 * is held after an error return (in particular, a failed LK_UPGRADE
 * or LK_FORCEUPGRADE will have released its shared access lock).
 */

/*
 * Indicator that no process holds exclusive lock
 */
#define LK_KERNPROC ((pid_t) -2)
#define LK_NOPROC ((pid_t) -1)

struct proc;

void	lockinit __P((struct lock__bsd__ *, int prio, char *wmesg, int timo,
			int flags));
int	lockmgr __P((struct lock__bsd__ *, u_int flags,
			simple_lock_t, struct proc *p));
int	lockstatus __P((struct lock__bsd__ *));

#endif /* __APPLE_API_UNSTABLE */

#endif	/* _SYS_LOCK_H_ */
Commit	Line	Data
1c79356b	1	/*
9bccf70c	2	* Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
1c79356b A	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
43866e37	6	* Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
1c79356b	7	*
43866e37 A	8	* This file contains Original Code and/or Modifications of Original Code
	9	* as defined in and that are subject to the Apple Public Source License
	10	* Version 2.0 (the 'License'). You may not use this file except in
	11	* compliance with the License. Please obtain a copy of the License at
	12	* http://www.opensource.apple.com/apsl/ and read it before using this
	13	* file.
	14	*
	15	* The Original Code and all software distributed under the License are
	16	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
1c79356b A	17	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
1c79356b A	18	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
43866e37 A	19	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	20	* Please see the License for the specific language governing rights and
	21	* limitations under the License.
1c79356b A	22	*
	23	* @APPLE_LICENSE_HEADER_END@
	24	*/
	25	/* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */
	26	/*
	27	* Copyright (c) 1995
	28	* The Regents of the University of California. All rights reserved.
	29	*
	30	* This code contains ideas from software contributed to Berkeley by
	31	* Avadis Tevanian, Jr., Michael Wayne Young, and the Mach Operating
	32	* System project at Carnegie-Mellon University.
	33	*
	34	* Redistribution and use in source and binary forms, with or without
	35	* modification, are permitted provided that the following conditions
	36	* are met:
	37	* 1. Redistributions of source code must retain the above copyright
	38	* notice, this list of conditions and the following disclaimer.
	39	* 2. Redistributions in binary form must reproduce the above copyright
	40	* notice, this list of conditions and the following disclaimer in the
	41	* documentation and/or other materials provided with the distribution.
	42	* 3. All advertising materials mentioning features or use of this software
	43	* must display the following acknowledgement:
	44	* This product includes software developed by the University of
	45	* California, Berkeley and its contributors.
	46	* 4. Neither the name of the University nor the names of its contributors
	47	* may be used to endorse or promote products derived from this software
	48	* without specific prior written permission.
	49	*
	50	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	51	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	52	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	53	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	54	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	55	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	56	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	57	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	58	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	59	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	60	* SUCH DAMAGE.
	61	*
	62	* @(#)lock.h 8.12 (Berkeley) 5/19/95
	63	*/
	64
	65	#ifndef _SYS_LOCK_H_
	66	#define _SYS_LOCK_H_
1c79356b	67
9bccf70c A	68	#include <sys/appleapiopts.h>
	69
	70	#ifdef KERNEL
	71	#ifdef __APPLE_API_UNSTABLE
1c79356b A	72	#include <kern/simple_lock.h>
	73	#include <kern/simple_lock_types.h>
	74
	75	#if defined(simple_lock_init)
	76	#undef simple_lock_init
	77	#endif
	78	#define simple_lock_init(l) usimple_lock_init((l),0)
	79
0b4e3aa0 A	80	#if defined(simple_lock)
	81	#undef simple_lock
	82	#endif
	83	#define simple_lock(l) ((void) 1)
	84
	85	#if defined(simple_unlock)
	86	#undef simple_unlock
	87	#endif
	88	#define simple_unlock(l) ((void) 1)
	89
	90	#if defined(simple_lock_try)
	91	#undef simple_lock_try
	92	#endif
	93	#define simple_lock_try(l) 1
	94
9bccf70c A	95	#if defined(thread_sleep_simple_lock)
	96	#undef thread_sleep_simple_lock
	97	#endif
	98	#define thread_sleep_simple_lock(l, e, i) thread_sleep_funnel((e), (i))
	99
	100	#endif /* __APPLE_API_UNSTABLE */
1c79356b A	101	#else /* KERNEL */
	102
	103	#ifndef _MACHINE_SIMPLE_LOCK_DATA_
	104	#define _MACHINE_SIMPLE_LOCK_DATA_
	105
	106	#include <mach/boolean.h>
	107
1c79356b A	108	struct slock{
	109	volatile unsigned int lock_data[10];
	110	};
1c79356b A	111	typedef struct slock simple_lock_data_t;
	112	typedef struct slock *simple_lock_t;
	113	#define decl_simple_lock_data(class,name) \
	114	class simple_lock_data_t name;
	115
	116	#endif /* _MACHINE_SIMPLE_LOCK_DATA_ */
	117
	118	#endif /* KERNEL */
9bccf70c A	119
9bccf70c A	120	#ifdef __APPLE_API_UNSTABLE
1c79356b A	121	/*
	122	* The general lock structure. Provides for multiple shared locks,
	123	* upgrading from shared to exclusive, and sleeping until the lock
	124	* can be gained. The simple locks are defined in <machine/param.h>.
	125	*/
	126	struct lock__bsd__ {
	127	simple_lock_data_t
	128	lk_interlock; /* lock on remaining fields */
	129	u_int lk_flags; /* see below */
	130	int lk_sharecount; /* # of accepted shared locks */
	131	int lk_waitcount; /* # of processes sleeping for lock */
	132	short lk_exclusivecount; /* # of recursive exclusive locks */
	133	short lk_prio; /* priority at which to sleep */
	134	char lk_wmesg; / resource sleeping (for tsleep) */
	135	int lk_timo; /* maximum sleep time (for tsleep) */
	136	pid_t lk_lockholder; /* pid of exclusive lock holder */
	137	void lk_lockthread; / thread which acquired excl lock */
	138	};
	139	/*
	140	* Lock request types:
	141	* LK_SHARED - get one of many possible shared locks. If a process
	142	* holding an exclusive lock requests a shared lock, the exclusive
	143	* lock(s) will be downgraded to shared locks.
	144	* LK_EXCLUSIVE - stop further shared locks, when they are cleared,
	145	* grant a pending upgrade if it exists, then grant an exclusive
	146	* lock. Only one exclusive lock may exist at a time, except that
	147	* a process holding an exclusive lock may get additional exclusive
	148	* locks if it explicitly sets the LK_CANRECURSE flag in the lock
	149	* request, or if the LK_CANRECUSE flag was set when the lock was
	150	* initialized.
	151	* LK_UPGRADE - the process must hold a shared lock that it wants to
	152	* have upgraded to an exclusive lock. Other processes may get
	153	* exclusive access to the resource between the time that the upgrade
	154	* is requested and the time that it is granted.
	155	* LK_EXCLUPGRADE - the process must hold a shared lock that it wants to
	156	* have upgraded to an exclusive lock. If the request succeeds, no
	157	* other processes will have gotten exclusive access to the resource
	158	* between the time that the upgrade is requested and the time that
	159	* it is granted. However, if another process has already requested
	160	* an upgrade, the request will fail (see error returns below).
	161	* LK_DOWNGRADE - the process must hold an exclusive lock that it wants
	162	* to have downgraded to a shared lock. If the process holds multiple
	163	* (recursive) exclusive locks, they will all be downgraded to shared
	164	* locks.
	165	* LK_RELEASE - release one instance of a lock.
	166	* LK_DRAIN - wait for all activity on the lock to end, then mark it
	167	* decommissioned. This feature is used before freeing a lock that
	168	* is part of a piece of memory that is about to be freed.
	169	*
	170	* These are flags that are passed to the lockmgr routine.
	171	*/
	172	#define LK_TYPE_MASK 0x0000000f /* type of lock sought */
	173	#define LK_SHARED 0x00000001 /* shared lock */
	174	#define LK_EXCLUSIVE 0x00000002 /* exclusive lock */
	175	#define LK_UPGRADE 0x00000003 /* shared-to-exclusive upgrade */
	176	#define LK_EXCLUPGRADE 0x00000004 /* first shared-to-exclusive upgrade */
	177	#define LK_DOWNGRADE 0x00000005 /* exclusive-to-shared downgrade */
	178	#define LK_RELEASE 0x00000006 /* release any type of lock */
	179	#define LK_DRAIN 0x00000007 /* wait for all lock activity to end */
	180	/*
	181	* External lock flags.
	182	*
	183	* The first three flags may be set in lock_init to set their mode permanently,
	184	* or passed in as arguments to the lock manager. The LK_REENABLE flag may be
185	* set only at the release of a lock obtained by drain.
186	*/
187	#define LK_EXTFLG_MASK 0x00000070 /* mask of external flags */
188	#define LK_NOWAIT 0x00000010 /* do not sleep to await lock */
189	#define LK_SLEEPFAIL 0x00000020 /* sleep, then return failure */
190	#define LK_CANRECURSE 0x00000040 /* allow recursive exclusive lock */
191	#define LK_REENABLE 0x00000080 /* lock is be reenabled after drain */
192	/*
193	* Internal lock flags.
194	*
195	* These flags are used internally to the lock manager.
196	*/
197	#define LK_WANT_UPGRADE 0x00000100 /* waiting for share-to-excl upgrade */
198	#define LK_WANT_EXCL 0x00000200 /* exclusive lock sought */
199	#define LK_HAVE_EXCL 0x00000400 /* exclusive lock obtained */
200	#define LK_WAITDRAIN 0x00000800 /* process waiting for lock to drain */
201	#define LK_DRAINING 0x00004000 /* lock is being drained */
202	#define LK_DRAINED 0x00008000 /* lock has been decommissioned */
203	/*
204	* Control flags
205	*
206	* Non-persistent external flags.
207	*/
208	#define LK_INTERLOCK 0x00010000 /* unlock passed simple lock after
209	getting lk_interlock */
210	#define LK_RETRY 0x00020000 /* vn_lock: retry until locked */
211
212	/*
213	* Lock return status.
214	*
215	* Successfully obtained locks return 0. Locks will always succeed
216	* unless one of the following is true:
217	* LK_FORCEUPGRADE is requested and some other process has already
218	* requested a lock upgrade (returns EBUSY).
219	* LK_WAIT is set and a sleep would be required (returns EBUSY).
220	* LK_SLEEPFAIL is set and a sleep was done (returns ENOLCK).
221	* PCATCH is set in lock priority and a signal arrives (returns
222	* either EINTR or ERESTART if system calls is to be restarted).
223	* Non-null lock timeout and timeout expires (returns EWOULDBLOCK).
224	* A failed lock attempt always returns a non-zero error value. No lock
225	* is held after an error return (in particular, a failed LK_UPGRADE
226	* or LK_FORCEUPGRADE will have released its shared access lock).
227	*/
228
229	/*
230	* Indicator that no process holds exclusive lock
231	*/
232	#define LK_KERNPROC ((pid_t) -2)
233	#define LK_NOPROC ((pid_t) -1)
234
235	struct proc;
236
237	void lockinit __P((struct lock__bsd__ , int prio, char wmesg, int timo,
238	int flags));
239	int lockmgr __P((struct lock__bsd__ *, u_int flags,
240	simple_lock_t, struct proc *p));
241	int lockstatus __P((struct lock__bsd__ *));
242
9bccf70c A	243	#endif /* __APPLE_API_UNSTABLE */
9bccf70c A	244
1c79356b	245	#endif /* _SYS_LOCK_H_ */