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

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This 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 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_
#ifdef KERNEL

#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)

#else /* KERNEL */

#ifndef	_MACHINE_SIMPLE_LOCK_DATA_
#define	_MACHINE_SIMPLE_LOCK_DATA_

#include <mach/boolean.h>

#if defined(__ppc__)
struct slock{
	volatile unsigned int lock_data[10];
};
#else
struct slock{
	volatile unsigned int lock_data[9];
};
#endif
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 */
/*
 * 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	/* _SYS_LOCK_H_ */
Commit	Line	Data
1c79356b A	1	/*
	2	* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
	6	* The contents of this file constitute Original Code as defined in and
	7	* are subject to the Apple Public Source License Version 1.1 (the
	8	* "License"). You may not use this file except in compliance with the
	9	* License. Please obtain a copy of the License at
	10	* http://www.apple.com/publicsource and read it before using this file.
	11	*
	12	* This Original Code and all software distributed under the License are
	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	16	* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	17	* License for the specific language governing rights and limitations
	18	* under the License.
	19	*
	20	* @APPLE_LICENSE_HEADER_END@
	21	*/
	22	/* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */
	23	/*
	24	* Copyright (c) 1995
	25	* The Regents of the University of California. All rights reserved.
	26	*
	27	* This code contains ideas from software contributed to Berkeley by
	28	* Avadis Tevanian, Jr., Michael Wayne Young, and the Mach Operating
	29	* System project at Carnegie-Mellon University.
	30	*
	31	* Redistribution and use in source and binary forms, with or without
	32	* modification, are permitted provided that the following conditions
	33	* are met:
	34	* 1. Redistributions of source code must retain the above copyright
	35	* notice, this list of conditions and the following disclaimer.
	36	* 2. Redistributions in binary form must reproduce the above copyright
	37	* notice, this list of conditions and the following disclaimer in the
	38	* documentation and/or other materials provided with the distribution.
	39	* 3. All advertising materials mentioning features or use of this software
	40	* must display the following acknowledgement:
	41	* This product includes software developed by the University of
	42	* California, Berkeley and its contributors.
	43	* 4. Neither the name of the University nor the names of its contributors
	44	* may be used to endorse or promote products derived from this software
	45	* without specific prior written permission.
	46	*
	47	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	48	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	49	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	50	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	51	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	52	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	53	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	54	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	55	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	56	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	57	* SUCH DAMAGE.
	58	*
	59	* @(#)lock.h 8.12 (Berkeley) 5/19/95
	60	*/
	61
	62	#ifndef _SYS_LOCK_H_
	63	#define _SYS_LOCK_H_
	64	#ifdef KERNEL
65
66	#include <kern/simple_lock.h>
67	#include <kern/simple_lock_types.h>
68
69	#if defined(simple_lock_init)
70	#undef simple_lock_init
71	#endif
72	#define simple_lock_init(l) usimple_lock_init((l),0)
73
74	#else /* KERNEL */
75
76	#ifndef _MACHINE_SIMPLE_LOCK_DATA_
77	#define _MACHINE_SIMPLE_LOCK_DATA_
78
79	#include <mach/boolean.h>
80
81	#if defined(__ppc__)
82	struct slock{
83	volatile unsigned int lock_data[10];
84	};
85	#else
86	struct slock{
87	volatile unsigned int lock_data[9];
88	};
89	#endif
90	typedef struct slock simple_lock_data_t;
91	typedef struct slock *simple_lock_t;
92	#define decl_simple_lock_data(class,name) \
93	class simple_lock_data_t name;
94
95	#endif /* _MACHINE_SIMPLE_LOCK_DATA_ */
96
97	#endif /* KERNEL */
98	/*
99	* The general lock structure. Provides for multiple shared locks,
100	* upgrading from shared to exclusive, and sleeping until the lock
101	* can be gained. The simple locks are defined in <machine/param.h>.
102	*/
103	struct lock__bsd__ {
104	simple_lock_data_t
105	lk_interlock; /* lock on remaining fields */
106	u_int lk_flags; /* see below */
107	int lk_sharecount; /* # of accepted shared locks */
108	int lk_waitcount; /* # of processes sleeping for lock */
109	short lk_exclusivecount; /* # of recursive exclusive locks */
110	short lk_prio; /* priority at which to sleep */
111	char lk_wmesg; / resource sleeping (for tsleep) */
112	int lk_timo; /* maximum sleep time (for tsleep) */
113	pid_t lk_lockholder; /* pid of exclusive lock holder */
114	void lk_lockthread; / thread which acquired excl lock */
115	};
116	/*
117	* Lock request types:
118	* LK_SHARED - get one of many possible shared locks. If a process
119	* holding an exclusive lock requests a shared lock, the exclusive
120	* lock(s) will be downgraded to shared locks.
121	* LK_EXCLUSIVE - stop further shared locks, when they are cleared,
122	* grant a pending upgrade if it exists, then grant an exclusive
123	* lock. Only one exclusive lock may exist at a time, except that
124	* a process holding an exclusive lock may get additional exclusive
125	* locks if it explicitly sets the LK_CANRECURSE flag in the lock
126	* request, or if the LK_CANRECUSE flag was set when the lock was
127	* initialized.
128	* LK_UPGRADE - the process must hold a shared lock that it wants to
129	* have upgraded to an exclusive lock. Other processes may get
130	* exclusive access to the resource between the time that the upgrade
131	* is requested and the time that it is granted.
132	* LK_EXCLUPGRADE - the process must hold a shared lock that it wants to
133	* have upgraded to an exclusive lock. If the request succeeds, no
134	* other processes will have gotten exclusive access to the resource
135	* between the time that the upgrade is requested and the time that
136	* it is granted. However, if another process has already requested
137	* an upgrade, the request will fail (see error returns below).
138	* LK_DOWNGRADE - the process must hold an exclusive lock that it wants
139	* to have downgraded to a shared lock. If the process holds multiple
140	* (recursive) exclusive locks, they will all be downgraded to shared
141	* locks.
142	* LK_RELEASE - release one instance of a lock.
143	* LK_DRAIN - wait for all activity on the lock to end, then mark it
144	* decommissioned. This feature is used before freeing a lock that
145	* is part of a piece of memory that is about to be freed.
146	*
147	* These are flags that are passed to the lockmgr routine.
148	*/
149	#define LK_TYPE_MASK 0x0000000f /* type of lock sought */
150	#define LK_SHARED 0x00000001 /* shared lock */
151	#define LK_EXCLUSIVE 0x00000002 /* exclusive lock */
152	#define LK_UPGRADE 0x00000003 /* shared-to-exclusive upgrade */
153	#define LK_EXCLUPGRADE 0x00000004 /* first shared-to-exclusive upgrade */
154	#define LK_DOWNGRADE 0x00000005 /* exclusive-to-shared downgrade */
155	#define LK_RELEASE 0x00000006 /* release any type of lock */
156	#define LK_DRAIN 0x00000007 /* wait for all lock activity to end */
157	/*
158	* External lock flags.
159	*
160	* The first three flags may be set in lock_init to set their mode permanently,
161	* or passed in as arguments to the lock manager. The LK_REENABLE flag may be
162	* set only at the release of a lock obtained by drain.
163	*/
164	#define LK_EXTFLG_MASK 0x00000070 /* mask of external flags */
165	#define LK_NOWAIT 0x00000010 /* do not sleep to await lock */
166	#define LK_SLEEPFAIL 0x00000020 /* sleep, then return failure */
167	#define LK_CANRECURSE 0x00000040 /* allow recursive exclusive lock */
168	#define LK_REENABLE 0x00000080 /* lock is be reenabled after drain */
169	/*
170	* Internal lock flags.
171	*
172	* These flags are used internally to the lock manager.
173	*/
174	#define LK_WANT_UPGRADE 0x00000100 /* waiting for share-to-excl upgrade */
175	#define LK_WANT_EXCL 0x00000200 /* exclusive lock sought */
176	#define LK_HAVE_EXCL 0x00000400 /* exclusive lock obtained */
177	#define LK_WAITDRAIN 0x00000800 /* process waiting for lock to drain */
178	#define LK_DRAINING 0x00004000 /* lock is being drained */
179	#define LK_DRAINED 0x00008000 /* lock has been decommissioned */
180	/*
181	* Control flags
182	*
183	* Non-persistent external flags.
184	*/
185	#define LK_INTERLOCK 0x00010000 /* unlock passed simple lock after
186	getting lk_interlock */
187	#define LK_RETRY 0x00020000 /* vn_lock: retry until locked */
188
189	/*
190	* Lock return status.
191	*
192	* Successfully obtained locks return 0. Locks will always succeed
193	* unless one of the following is true:
194	* LK_FORCEUPGRADE is requested and some other process has already
195	* requested a lock upgrade (returns EBUSY).
196	* LK_WAIT is set and a sleep would be required (returns EBUSY).
197	* LK_SLEEPFAIL is set and a sleep was done (returns ENOLCK).
198	* PCATCH is set in lock priority and a signal arrives (returns
199	* either EINTR or ERESTART if system calls is to be restarted).
200	* Non-null lock timeout and timeout expires (returns EWOULDBLOCK).
201	* A failed lock attempt always returns a non-zero error value. No lock
202	* is held after an error return (in particular, a failed LK_UPGRADE
203	* or LK_FORCEUPGRADE will have released its shared access lock).
204	*/
205
206	/*
207	* Indicator that no process holds exclusive lock
208	*/
209	#define LK_KERNPROC ((pid_t) -2)
210	#define LK_NOPROC ((pid_t) -1)
211
212	struct proc;
213
214	void lockinit __P((struct lock__bsd__ , int prio, char wmesg, int timo,
215	int flags));
216	int lockmgr __P((struct lock__bsd__ *, u_int flags,
217	simple_lock_t, struct proc *p));
218	int lockstatus __P((struct lock__bsd__ *));
219
220	#endif /* _SYS_LOCK_H_ */