-#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 */
-
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