/*
 * Copyright (c) 2000-2005 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_

#include <sys/appleapiopts.h>
#include <sys/types.h>
#include <sys/cdefs.h>

#ifdef KERNEL

#include <kern/locks.h>


#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 /* KERNEL */

#ifdef BSD_KERNEL_PRIVATE
/*
 * 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__ {
        void * lk_interlock[10];                /* 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 */
        const 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 */
};

// LP64todo - should this move?

/* LP64 version of lock__bsd__.  all pointers 
 * grow when we're dealing with a 64-bit process.
 * WARNING - keep in sync with lock__bsd__
 */

#if __DARWIN_ALIGN_NATURAL
#pragma options align=natural
#endif

struct user_lock__bsd__ {
        user_addr_t     lk_interlock[10];   /* 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 */
        user_addr_t lk_wmesg;           /* resource sleeping (for tsleep) */
        int                     lk_timo;                        /* maximum sleep time (for tsleep) */
        pid_t           lk_lockholder;          /* pid of exclusive lock holder */
        user_addr_t     lk_lockthread;          /* thread which acquired excl lock */
};

#if __DARWIN_ALIGN_NATURAL
#pragma options align=reset
#endif

/*
 * 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(struct lock__bsd__ *, int prio, const char *wmesg, int timo,
                        int flags);
int     lockmgr(struct lock__bsd__ *, u_int flags,
                        void *, struct proc *p);
int     lockstatus(struct lock__bsd__ *);

#endif /* BSD_KERNEL_PRIVATE  */

#endif  /* _SYS_LOCK_H_ */