/*
 * Copyright (c) 2003-2016 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * 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. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * 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_OSREFERENCE_LICENSE_HEADER_END@
 */
/*-
 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 *	$FreeBSD: src/sys/sys/event.h,v 1.5.2.5 2001/12/14 19:21:22 jlemon Exp $
 */

#ifndef _SYS_EVENT_H_
#define _SYS_EVENT_H_

#include <machine/types.h>
#include <sys/cdefs.h>
#include <stdint.h>

#define EVFILT_READ		(-1)
#define EVFILT_WRITE		(-2)
#define EVFILT_AIO		(-3)	/* attached to aio requests */
#define EVFILT_VNODE		(-4)	/* attached to vnodes */
#define EVFILT_PROC		(-5)	/* attached to struct proc */
#define EVFILT_SIGNAL		(-6)	/* attached to struct proc */
#define EVFILT_TIMER		(-7)	/* timers */
#define EVFILT_MACHPORT         (-8)	/* Mach portsets */
#define EVFILT_FS		(-9)	/* Filesystem events */
#define EVFILT_USER             (-10)   /* User events */
					/* (-11) unused */
#define EVFILT_VM		(-12)	/* Virtual memory events */

#ifdef PRIVATE
#define EVFILT_SOCK		(-13)	/* Socket events */
#define EVFILT_MEMORYSTATUS	(-14)	/* Memorystatus events */
#endif /* PRIVATE */
#define EVFILT_EXCEPT		(-15)	/* Exception events */

#define EVFILT_SYSCOUNT		15
#define EVFILT_THREADMARKER	EVFILT_SYSCOUNT /* Internal use only */

#pragma pack(4)

struct kevent {
	uintptr_t	ident;		/* identifier for this event */
	int16_t		filter;		/* filter for event */
	uint16_t	flags;		/* general flags */
	uint32_t	fflags;		/* filter-specific flags */
	intptr_t	data;		/* filter-specific data */
	void		*udata;		/* opaque user data identifier */
};

#ifdef KERNEL_PRIVATE

struct user64_kevent {
	uint64_t	ident;		/* identifier for this event */
	int16_t		filter;		/* filter for event */
	uint16_t	flags;		/* general flags */
	uint32_t	fflags;		/* filter-specific flags */
	int64_t		data;		/* filter-specific data */
	user_addr_t	udata;		/* opaque user data identifier */
};

struct user32_kevent {
	uint32_t	ident;		/* identifier for this event */
	int16_t		filter;		/* filter for event */
	uint16_t	flags;		/* general flags */
	uint32_t	fflags;		/* filter-specific flags */
	int32_t		data;		/* filter-specific data */
	user32_addr_t	udata;  /* opaque user data identifier */
};

struct kevent_internal_s {
	uint64_t    ident;      /* identifier for this event */
	int16_t     filter;     /* filter for event */
	uint16_t    flags;      /* general flags */
	int32_t		qos;		/* quality of service */
	uint32_t    fflags;     /* filter-specific flags */
//	uint32_t	xflags;     /* extra filter-specific flags */
	int64_t     data;       /* filter-specific data */
	uint64_t    udata;      /* opaque user data identifier */
	uint64_t    ext[4];     /* filter-specific extensions */
};

#endif

#pragma pack()

struct kevent64_s {
	uint64_t	ident;		/* identifier for this event */
	int16_t		filter;		/* filter for event */
	uint16_t	flags;		/* general flags */
	uint32_t	fflags;		/* filter-specific flags */
	int64_t		data;		/* filter-specific data */
	uint64_t	udata;		/* opaque user data identifier */
	uint64_t	ext[2];		/* filter-specific extensions */
};

#ifdef PRIVATE
struct kevent_qos_s {
	uint64_t	ident;		/* identifier for this event */
	int16_t		filter;		/* filter for event */
	uint16_t	flags;		/* general flags */
	int32_t		qos;		/* quality of service */
	uint64_t	udata;		/* opaque user data identifier */
	uint32_t	fflags;		/* filter-specific flags */
	uint32_t	xflags;		/* extra filter-specific flags */
	int64_t		data;		/* filter-specific data */
	uint64_t	ext[4];		/* filter-specific extensions */
};
#endif /* PRIVATE */

#define EV_SET(kevp, a, b, c, d, e, f) do {	\
	struct kevent *__kevp__ = (kevp);	\
	__kevp__->ident = (a);			\
	__kevp__->filter = (b);			\
	__kevp__->flags = (c);			\
	__kevp__->fflags = (d);			\
	__kevp__->data = (e);			\
	__kevp__->udata = (f);			\
} while(0)

#define EV_SET64(kevp, a, b, c, d, e, f, g, h) do {	\
	struct kevent64_s *__kevp__ = (kevp);		\
	__kevp__->ident = (a);				\
	__kevp__->filter = (b);				\
	__kevp__->flags = (c);				\
	__kevp__->fflags = (d);				\
	__kevp__->data = (e);				\
	__kevp__->udata = (f);				\
	__kevp__->ext[0] = (g);				\
	__kevp__->ext[1] = (h);				\
} while(0)


/* kevent system call flags */
#define KEVENT_FLAG_NONE               0x000	/* no flag value */
#define KEVENT_FLAG_IMMEDIATE          0x001	/* immediate timeout */
#define KEVENT_FLAG_ERROR_EVENTS       0x002	/* output events only include change errors */

#ifdef PRIVATE

/*
 * Rather than provide an EV_SET_QOS macro for kevent_qos_t structure
 * initialization, we encourage use of named field initialization support
 * instead.
 */

#define KEVENT_FLAG_STACK_EVENTS       0x004	/* output events treated as stack (grows down) */
#define KEVENT_FLAG_STACK_DATA	       0x008	/* output data allocated as stack (grows down) */
#define KEVENT_FLAG_WORKQ              0x020	/* interact with the default workq kq */
#define KEVENT_FLAG_WORKQ_MANAGER      0x200	/* current thread is the workq manager */

#ifdef XNU_KERNEL_PRIVATE

#define KEVENT_FLAG_LEGACY32           0x040	/* event data in legacy 32-bit format */
#define KEVENT_FLAG_LEGACY64           0x080	/* event data in legacy 64-bit format */
#define KEVENT_FLAG_KERNEL             0x100	/* caller is in-kernel */
#define KEVENT_FLAG_USER	(KEVENT_FLAG_IMMEDIATE | KEVENT_FLAG_ERROR_EVENTS | \
                             KEVENT_FLAG_STACK_EVENTS | KEVENT_FLAG_STACK_DATA | \
                             KEVENT_FLAG_WORKQ)

/* 
 * Since some filter ops are not part of the standard sysfilt_ops, we 
 * use kn_filtid starting from EVFILT_SYSCOUNT to identify these cases. 
 * This is to let kn_fops() get the correct fops for all cases.
*/
#define EVFILTID_KQREAD         (EVFILT_SYSCOUNT)   
#define EVFILTID_PIPE_R         (EVFILT_SYSCOUNT + 1)
#define EVFILTID_PIPE_W         (EVFILT_SYSCOUNT + 2)
#define EVFILTID_PTSD           (EVFILT_SYSCOUNT + 3)
#define EVFILTID_SOREAD         (EVFILT_SYSCOUNT + 4)
#define EVFILTID_SOWRITE        (EVFILT_SYSCOUNT + 5)
#define EVFILTID_SCK            (EVFILT_SYSCOUNT + 6)
#define EVFILTID_SOEXCEPT       (EVFILT_SYSCOUNT + 7)
#define EVFILTID_SPEC           (EVFILT_SYSCOUNT + 8)
#define EVFILTID_BPFREAD        (EVFILT_SYSCOUNT + 9)
#define EVFILTID_NECP_FD        (EVFILT_SYSCOUNT + 10)
#define EVFILTID_FSEVENT        (EVFILT_SYSCOUNT + 13)
#define EVFILTID_VN             (EVFILT_SYSCOUNT + 14)

#define EVFILTID_MAX 			(EVFILT_SYSCOUNT + 15)

#endif /* XNU_KERNEL_PRIVATE */

#define EV_SET_QOS 0

#endif /* PRIVATE */

/* actions */
#define EV_ADD              0x0001		/* add event to kq (implies enable) */
#define EV_DELETE           0x0002		/* delete event from kq */
#define EV_ENABLE           0x0004		/* enable event */
#define EV_DISABLE          0x0008		/* disable event (not reported) */

/* flags */
#define EV_ONESHOT          0x0010		/* only report one occurrence */
#define EV_CLEAR            0x0020		/* clear event state after reporting */
#define EV_RECEIPT          0x0040		/* force immediate event output */
                                		/* ... with or without EV_ERROR */
                                  		/* ... use KEVENT_FLAG_ERROR_EVENTS */
                                		/*     on syscalls supporting flags */

#define EV_DISPATCH         0x0080		/* disable event after reporting */
#define EV_UDATA_SPECIFIC   0x0100		/* unique kevent per udata value */

#define EV_DISPATCH2        (EV_DISPATCH | EV_UDATA_SPECIFIC)
                                  		/* ... in combination with EV_DELETE */
                                  		/* will defer delete until udata-specific */
                                  		/* event enabled. EINPROGRESS will be */
                                  		/* returned to indicate the deferral */

#define EV_VANISHED         0x0200		/* report that source has vanished  */
                                  		/* ... only valid with EV_DISPATCH2 */

#define EV_SYSFLAGS         0xF000		/* reserved by system */
#define EV_FLAG0            0x1000		/* filter-specific flag */
#define EV_FLAG1            0x2000		/* filter-specific flag */

/* returned values */
#define EV_EOF              0x8000		/* EOF detected */
#define EV_ERROR            0x4000		/* error, data contains errno */

/*
 * Filter specific flags for EVFILT_READ
 *
 * The default behavior for EVFILT_READ is to make the "read" determination
 * relative to the current file descriptor read pointer. 
 *
 * The EV_POLL flag indicates the determination should be made via poll(2)
 * semantics. These semantics dictate always returning true for regular files,
 * regardless of the amount of unread data in the file.  
 *
 * On input, EV_OOBAND specifies that filter should actively return in the
 * presence of OOB on the descriptor. It implies that filter will return
 * if there is OOB data available to read OR when any other condition
 * for the read are met (for example number of bytes regular data becomes >=
 * low-watermark).
 * If EV_OOBAND is not set on input, it implies that the filter should not actively
 * return for out of band data on the descriptor. The filter will then only return
 * when some other condition for read is met (ex: when number of regular data bytes
 * >=low-watermark OR when socket can't receive more data (SS_CANTRCVMORE)).
 *
 * On output, EV_OOBAND indicates the presence of OOB data on the descriptor.
 * If it was not specified as an input parameter, then the data count is the
 * number of bytes before the current OOB marker, else data count is the number
 * of bytes beyond OOB marker.
 */
#define EV_POLL		EV_FLAG0
#define EV_OOBAND	EV_FLAG1

/*
 * data/hint fflags for EVFILT_USER, shared with userspace
 */

/*
 * On input, NOTE_TRIGGER causes the event to be triggered for output.
 */
#define NOTE_TRIGGER	0x01000000

/*
 * On input, the top two bits of fflags specifies how the lower twenty four 
 * bits should be applied to the stored value of fflags.
 *
 * On output, the top two bits will always be set to NOTE_FFNOP and the
 * remaining twenty four bits will contain the stored fflags value.
 */
#define NOTE_FFNOP      0x00000000              /* ignore input fflags */
#define NOTE_FFAND      0x40000000              /* and fflags */
#define NOTE_FFOR       0x80000000              /* or fflags */
#define NOTE_FFCOPY     0xc0000000              /* copy fflags */
#define NOTE_FFCTRLMASK 0xc0000000              /* mask for operations */
#define NOTE_FFLAGSMASK	0x00ffffff 

/*
 * data/hint fflags for EVFILT_{READ|WRITE}, shared with userspace
 *
 * The default behavior for EVFILT_READ is to make the determination
 * realtive to the current file descriptor read pointer.
 */
#define NOTE_LOWAT	0x00000001		/* low water mark */

/* data/hint flags for EVFILT_EXCEPT, shared with userspace */
#define NOTE_OOB	0x00000002		/* OOB data */

/*
 * data/hint fflags for EVFILT_VNODE, shared with userspace
 */
#define	NOTE_DELETE	0x00000001		/* vnode was removed */
#define	NOTE_WRITE	0x00000002		/* data contents changed */
#define	NOTE_EXTEND	0x00000004		/* size increased */
#define	NOTE_ATTRIB	0x00000008		/* attributes changed */
#define	NOTE_LINK	0x00000010		/* link count changed */
#define	NOTE_RENAME	0x00000020		/* vnode was renamed */
#define	NOTE_REVOKE	0x00000040		/* vnode access was revoked */
#define NOTE_NONE	0x00000080		/* No specific vnode event: to test for EVFILT_READ activation*/
#define NOTE_FUNLOCK	0x00000100		/* vnode was unlocked by flock(2) */

/*
 * data/hint fflags for EVFILT_PROC, shared with userspace
 *
 * Please note that EVFILT_PROC and EVFILT_SIGNAL share the same knote list
 * that hangs off the proc structure. They also both play games with the hint
 * passed to KNOTE(). If NOTE_SIGNAL is passed as a hint, then the lower bits
 * of the hint contain the signal. IF NOTE_FORK is passed, then the lower bits
 * contain the PID of the child (but the pid does not get passed through in
 * the actual kevent).
 */
enum {
	eNoteReapDeprecated __deprecated_enum_msg("This kqueue(2) EVFILT_PROC flag is deprecated") = 0x10000000
};

#define	NOTE_EXIT		0x80000000	/* process exited */
#define	NOTE_FORK		0x40000000	/* process forked */
#define	NOTE_EXEC		0x20000000	/* process exec'd */
#define	NOTE_REAP		((unsigned int)eNoteReapDeprecated /* 0x10000000 */)	/* process reaped */
#define	NOTE_SIGNAL		0x08000000	/* shared with EVFILT_SIGNAL */
#define	NOTE_EXITSTATUS		0x04000000	/* exit status to be returned, valid for child process only */
#define	NOTE_EXIT_DETAIL	0x02000000	/* provide details on reasons for exit */

#define	NOTE_PDATAMASK	0x000fffff		/* mask for signal & exit status */
#define	NOTE_PCTRLMASK	(~NOTE_PDATAMASK)

/*
 * If NOTE_EXITSTATUS is present, provide additional info about exiting process.
 */
enum {
	eNoteExitReparentedDeprecated __deprecated_enum_msg("This kqueue(2) EVFILT_PROC flag is no longer sent") = 0x00080000 
};
#define NOTE_EXIT_REPARENTED	((unsigned int)eNoteExitReparentedDeprecated)	/* exited while reparented */

/*
 * If NOTE_EXIT_DETAIL is present, these bits indicate specific reasons for exiting.
 */
#define NOTE_EXIT_DETAIL_MASK		0x00070000
#define	NOTE_EXIT_DECRYPTFAIL		0x00010000 
#define	NOTE_EXIT_MEMORY		0x00020000
#define NOTE_EXIT_CSERROR		0x00040000

#ifdef PRIVATE

/*
 * If NOTE_EXIT_MEMORY is present, these bits indicate specific jetsam condition.
 */
#define NOTE_EXIT_MEMORY_DETAIL_MASK	0xfe000000
#define NOTE_EXIT_MEMORY_VMPAGESHORTAGE	0x80000000	/* jetsam condition: lowest jetsam priority proc killed due to vm page shortage */
#define NOTE_EXIT_MEMORY_VMTHRASHING	0x40000000	/* jetsam condition: lowest jetsam priority proc killed due to vm thrashing */
#define NOTE_EXIT_MEMORY_HIWAT		0x20000000	/* jetsam condition: process reached its high water mark */
#define NOTE_EXIT_MEMORY_PID		0x10000000	/* jetsam condition: special pid kill requested */
#define NOTE_EXIT_MEMORY_IDLE		0x08000000	/* jetsam condition: idle process cleaned up */
#define NOTE_EXIT_MEMORY_VNODE		0X04000000	/* jetsam condition: virtual node kill */
#define NOTE_EXIT_MEMORY_FCTHRASHING	0x02000000	/* jetsam condition: lowest jetsam priority proc killed due to filecache thrashing */

#endif

/*
 * data/hint fflags for EVFILT_VM, shared with userspace.
 */
#define NOTE_VM_PRESSURE			0x80000000              /* will react on memory pressure */
#define NOTE_VM_PRESSURE_TERMINATE		0x40000000              /* will quit on memory pressure, possibly after cleaning up dirty state */
#define NOTE_VM_PRESSURE_SUDDEN_TERMINATE	0x20000000		/* will quit immediately on memory pressure */
#define NOTE_VM_ERROR				0x10000000              /* there was an error */

#ifdef PRIVATE

/*
 * data/hint fflags for EVFILT_MEMORYSTATUS, shared with userspace.
 */
#define NOTE_MEMORYSTATUS_PRESSURE_NORMAL	0x00000001	/* system memory pressure has returned to normal */
#define NOTE_MEMORYSTATUS_PRESSURE_WARN		0x00000002	/* system memory pressure has changed to the warning state */
#define NOTE_MEMORYSTATUS_PRESSURE_CRITICAL	0x00000004	/* system memory pressure has changed to the critical state */
#define NOTE_MEMORYSTATUS_LOW_SWAP		0x00000008	/* system is in a low-swap state */
#define NOTE_MEMORYSTATUS_PROC_LIMIT_WARN	0x00000010	/* process memory limit has hit a warning state */
#define NOTE_MEMORYSTATUS_PROC_LIMIT_CRITICAL	0x00000020	/* process memory limit has hit a critical state - soft limit */

typedef enum vm_pressure_level {
        kVMPressureNormal   = 0,
        kVMPressureWarning  = 1,
        kVMPressureUrgent   = 2,
        kVMPressureCritical = 3,
} vm_pressure_level_t;

#endif

/*
 * data/hint fflags for EVFILT_TIMER, shared with userspace.
 * The default is a (repeating) interval timer with the data
 * specifying the timeout interval in milliseconds.
 *
 * All timeouts are implicitly EV_CLEAR events.
 */
#define NOTE_SECONDS	0x00000001		/* data is seconds         */
#define NOTE_USECONDS	0x00000002		/* data is microseconds    */
#define NOTE_NSECONDS	0x00000004		/* data is nanoseconds     */
#define NOTE_ABSOLUTE	0x00000008		/* absolute timeout        */
						/* ... implicit EV_ONESHOT */
#define NOTE_LEEWAY	0x00000010		/* ext[1] holds leeway for power aware timers */
#define NOTE_CRITICAL	0x00000020		/* system does minimal timer coalescing */
#define NOTE_BACKGROUND	0x00000040		/* system does maximum timer coalescing */
#define NOTE_MACH_CONTINUOUS_TIME	0x00000080		/* use continuous time base */
#ifdef PRIVATE
/*
 * data/hint fflags for EVFILT_SOCK, shared with userspace.
 *
 */
#define	NOTE_CONNRESET		0x00000001 /* Received RST */
#define	NOTE_READCLOSED		0x00000002 /* Read side is shutdown */
#define	NOTE_WRITECLOSED	0x00000004 /* Write side is shutdown */
#define	NOTE_TIMEOUT		0x00000008 /* timeout: rexmt, keep-alive or persist */
#define	NOTE_NOSRCADDR		0x00000010 /* source address not available */
#define	NOTE_IFDENIED		0x00000020 /* interface denied connection */
#define	NOTE_SUSPEND		0x00000040 /* output queue suspended */
#define	NOTE_RESUME		0x00000080 /* output queue resumed */
#define NOTE_KEEPALIVE		0x00000100 /* TCP Keepalive received */
#define NOTE_ADAPTIVE_WTIMO	0x00000200 /* TCP adaptive write timeout */
#define NOTE_ADAPTIVE_RTIMO	0x00000400 /* TCP adaptive read timeout */
#define	NOTE_CONNECTED		0x00000800 /* socket is connected */
#define	NOTE_DISCONNECTED	0x00001000 /* socket is disconnected */
#define	NOTE_CONNINFO_UPDATED	0x00002000 /* connection info was updated */
#define	NOTE_NOTIFY_ACK		0x00004000 /* notify acknowledgement */

#define	EVFILT_SOCK_LEVEL_TRIGGER_MASK \
    (NOTE_READCLOSED | NOTE_WRITECLOSED | NOTE_SUSPEND | NOTE_RESUME | NOTE_CONNECTED | NOTE_DISCONNECTED)

#define EVFILT_SOCK_ALL_MASK \
    (NOTE_CONNRESET | NOTE_READCLOSED | NOTE_WRITECLOSED | NOTE_TIMEOUT | NOTE_NOSRCADDR | NOTE_IFDENIED | NOTE_SUSPEND | NOTE_RESUME | NOTE_KEEPALIVE | NOTE_ADAPTIVE_WTIMO | NOTE_ADAPTIVE_RTIMO | NOTE_CONNECTED | NOTE_DISCONNECTED | NOTE_CONNINFO_UPDATED | NOTE_NOTIFY_ACK)

#endif /* PRIVATE */

/*
 * data/hint fflags for EVFILT_MACHPORT, shared with userspace.
 *
 * Only portsets are supported at this time.
 *
 * The fflags field can optionally contain the MACH_RCV_MSG, MACH_RCV_LARGE,
 * and related trailer receive options as defined in <mach/message.h>.
 * The presence of these flags directs the kevent64() call to attempt to receive
 * the message during kevent delivery, rather than just indicate that a message exists.
 * On setup, The ext[0] field contains the receive buffer pointer and ext[1] contains
 * the receive buffer length.  Upon event delivery, the actual received message size
 * is returned in ext[1].  As with mach_msg(), the buffer must be large enough to
 * receive the message and the requested (or default) message trailers.  In addition,
 * the fflags field contains the return code normally returned by mach_msg().
 *
 * If MACH_RCV_MSG is specified, and the ext[1] field specifies a zero length, the
 * system call argument specifying an ouput area (kevent_qos) will be consulted. If
 * the system call specified an output data area, the user-space address
 * of the received message is carved from that provided output data area (if enough
 * space remains there). The address and length of each received message is 
 * returned in the ext[0] and ext[1] fields (respectively) of the corresponding kevent.
 *
 * IF_MACH_RCV_VOUCHER_CONTENT is specified, the contents of the message voucher is
 * extracted (as specified in the xflags field) and stored in ext[2] up to ext[3]
 * length.  If the input length is zero, and the system call provided a data area,
 * the space for the voucher content is carved from the provided space and its
 * address and length is returned in ext[2] and ext[3] respectively.
 *
 * If no message receipt options were provided in the fflags field on setup, no
 * message is received by this call. Instead, on output, the data field simply
 * contains the name of the actual port detected with a message waiting.
 */

/*
 * DEPRECATED!!!!!!!!!
 * NOTE_TRACK, NOTE_TRACKERR, and NOTE_CHILD are no longer supported as of 10.5
 */
/* additional flags for EVFILT_PROC */
#define	NOTE_TRACK	0x00000001		/* follow across forks */
#define	NOTE_TRACKERR	0x00000002		/* could not track child */
#define	NOTE_CHILD	0x00000004		/* am a child process */



#ifndef KERNEL
/* Temporay solution for BootX to use inode.h till kqueue moves to vfs layer */
#include <sys/queue.h> 
struct knote;
SLIST_HEAD(klist, knote);
#endif

#ifdef KERNEL

#ifdef XNU_KERNEL_PRIVATE
#include <sys/queue.h> 
#include <kern/kern_types.h>

#ifdef MALLOC_DECLARE
MALLOC_DECLARE(M_KQUEUE);
#endif

TAILQ_HEAD(kqtailq, knote);	/* a list of "queued" events */

/* Bit size for packed field within knote */
#define KNOTE_KQ_BITSIZE 			40


/* index into various kq queues */
typedef uint8_t kq_index_t; 
typedef uint16_t kn_status_t;

#define KN_ACTIVE          0x0001		/* event has been triggered */
#define KN_QUEUED          0x0002		/* event is on queue */
#define KN_DISABLED        0x0004		/* event is disabled */
#define KN_DROPPING        0x0008		/* knote is being dropped */
#define KN_USEWAIT         0x0010		/* wait for knote use */
#define KN_ATTACHING       0x0020		/* event is pending attach */
#define KN_STAYACTIVE      0x0040		/* force event to stay active */
#define KN_DEFERDELETE     0x0080		/* defer delete until re-enabled */
#define KN_ATTACHED        0x0100		/* currently attached to source */
#define KN_DISPATCH        0x0200		/* disables as part of deliver */
#define KN_UDATA_SPECIFIC  0x0400		/* udata is part of matching */
#define KN_SUPPRESSED      0x0800		/* event is suppressed during delivery */
#define KN_STOLENDROP	   0x1000		/* someone stole the drop privilege */
#define KN_REQVANISH       0x2000       /* requested EV_VANISH */
#define KN_VANISHED        0x4000       /* has vanished */

#define KN_DISPATCH2		(KN_DISPATCH | KN_UDATA_SPECIFIC)
					/* combination defines deferred-delete mode enabled */

struct __attribute__((__packed__)) knote {
	uint16_t                 kn_inuse;          /* inuse count */
	kn_status_t              kn_status;         /* status bits */
	int                      kn_hookid;
	TAILQ_ENTRY(knote)       kn_tqe;            /* linkage for tail queue */
	SLIST_ENTRY(knote)       kn_link;           /* linkage for search list */
	SLIST_ENTRY(knote)       kn_selnext;        /* klist element chain */
	union {
		struct fileproc      *p_fp;             /* file data pointer */
		struct proc          *p_proc;           /* proc pointer */
		struct ipc_mqueue    *p_mqueue;         /* pset pointer */
	} kn_ptr;
	uint64_t				 kn_req_index:4, 				/* requested qos index */
							 kn_qos_index:4, 				/* in-use qos index */
							 kn_qos_override:4, 			/* qos override index */
							 kn_reserved:4, 				/* reserved bits */
							 kn_filtid:8, 					/* filter id to index filter ops */
							 kn_kq_packed:KNOTE_KQ_BITSIZE; /* packed pointer for kq */

	int                      kn_sfflags;        /* saved filter flags */
	union {
		void                 *kn_hook;
		uint64_t            kn_hook_data;
	};
	int64_t                  kn_sdata;          /* saved data field */
	struct kevent_internal_s kn_kevent;

#define kn_id		kn_kevent.ident
#define kn_filter	kn_kevent.filter
#define kn_flags	kn_kevent.flags
#define kn_qos		kn_kevent.qos
#define kn_udata	kn_kevent.udata
#define kn_fflags	kn_kevent.fflags
#define kn_xflags	kn_kevent.xflags
#define kn_data		kn_kevent.data
#define kn_ext		kn_kevent.ext
#define kn_fp		kn_ptr.p_fp
};

static inline struct kqueue *knote_get_kq(struct knote *kn)
{
	if (!(kn->kn_kq_packed))
		return 0;
	else
		return (struct kqueue *)((uintptr_t)(kn->kn_kq_packed) + (uintptr_t)VM_MIN_KERNEL_AND_KEXT_ADDRESS);
}

static inline void knote_set_kq(struct knote *kn, void *kq)
{
	if (!kq)
		kn->kn_kq_packed = 0;
	else {
		uint64_t offset = ((uintptr_t)kq - (uintptr_t)VM_MIN_KERNEL_AND_KEXT_ADDRESS);
		kn->kn_kq_packed = offset;
	}
}

struct filt_process_s {
	int fp_fd;
	unsigned int fp_flags;
	user_addr_t fp_data_out;
	user_size_t fp_data_size;
	user_size_t fp_data_resid;
};
typedef struct filt_process_s *filt_process_data_t;

/*
 * Filter operators
 *
 * These routines, provided by each filter, are called to attach, detach, deliver events,
 * change/update filter registration and process/deliver events.  They are called with the
 * with a use-count referenced knote, with the kq unlocked.  Here are more details:
 *
 * f_isfd -
 *        identifies if the "ident" field in the kevent structure is a file-descriptor.
 *
 *        If so, the knote is associated with the file descriptor prior to attach and
 *        auto-removed when the file descriptor is closed (this latter behavior may change
 *        for EV_DISPATCH2 kevent types to allow delivery of events identifying unintended
 *        closes).
 *
 *        Otherwise the knote is hashed by the ident and has no auto-close behavior.
 *
 * f_attach -
 *	  called to attach the knote to the underlying object that will be delivering events
 *        through it when EV_ADD is supplied and no existing matching event is found
 *
 *        provided a knote that is pre-attached to the fd or hashed (see above) but is
 *        specially marked to avoid concurrent access until the attach is complete. The
 *        kevent structure embedded in this knote has been filled in with a sanitized
 *        version of the user-supplied kevent data.  However, the user-supplied filter-specific
 *        flags (fflags) and data fields have been moved into the knote's kn_sfflags and kn_sdata
 *        fields respectively.  These are usually interpretted as a set of "interest" flags and
 *        data by each filter - to be matched against delivered events.
 *
 *        The attach operator indicated errors by setting the EV_ERROR flog in the flags field
 *        embedded in the knote's kevent structure - with the specific error indicated in the
 *        corresponding data field.
 *
 *        The return value indicates if the knote should already be considered "activated" at
 *        the time of attach (one or more of the interest events has already occured).
 *
 * f_detach -
 *        called to disassociate the knote from the underlying object delivering events
 *	  the filter should not attempt to deliver events through this knote after this
 *        operation returns control to the kq system.
 *
 * f_event -
 *        if the knote() function (or KNOTE() macro) is called against a list of knotes,
 *        this operator will be called on each knote in the list.
 *
 *        The "hint" parameter is completely filter-specific, but usually indicates an
 *        event or set of events that have occured against the source object associated
 *        with the list.
 *
 *        The return value indicates if the knote should already be considered "activated" at
 *        the time of attach (one or more of the interest events has already occured).
 *
 * f_process -
 *        called when attempting to deliver triggered events to user-space. 
 *
 *        If the knote was previously activated, this operator will be called when a
 *        thread is trying to deliver events to user-space.  The filter gets one last
 *        chance to determine if the event/events are still interesting for this knote
 *        (are the conditions still right to deliver an event).  If so, the filter
 *        fills in the output kevent structure with the information to be delivered.
 *
 *        The input context/data parameter is used during event delivery.  Some
 *        filters allow additional data delivery as part of event delivery.  This
 *        context field indicates if space was made available for these additional
 *        items and how that space is to be allocated/carved-out.
 *
 *        The filter may set EV_CLEAR or EV_ONESHOT in the output flags field to indicate
 *        special post-delivery dispositions for the knote.
 *
 *        EV_CLEAR - indicates that all matching events have been delivered. Even
 *                   though there were events to deliver now, there will not be any
 *                   more until some additional events are delivered to the knote
 *                   via the f_event operator, or the interest set is changed via
 *                   the f_touch operator.  The knote can remain deactivated after
 *                   processing this event delivery.
 *
 *        EV_ONESHOT - indicates that this is the last event to be delivered via
 *                   this knote.  It will automatically be deleted upon delivery
 *                   (or if in dispatch-mode, upon re-enablement after this delivery).
 *
 *        The return value indicates if the knote has delivered an output event.
 *        Unless one of the special output flags was set in the output kevent, a non-
 *        zero return value ALSO indicates that the knote should be re-activated
 *        for future event processing (in case it delivers level-based or a multi-edge
 *        type events like message queues that already exist).  
 *
 *        NOTE: In the future, the boolean may change to an enum that allows more
 *              explicit indication of just delivering a current event vs delivering
 *              an event with more events still pending.
 *
 * f_peek -
 *        For knotes marked KN_STAYACTIVE, indicate if the knote is truly active at
 *        the moment (not used for event delivery, but for status checks).
 */

struct filterops {
	int	f_isfd;		/* true if ident == filedescriptor */
	int	(*f_attach)(struct knote *kn);
	void	(*f_detach)(struct knote *kn);
	int	(*f_event)(struct knote *kn, long hint);
	int     (*f_touch)(struct knote *kn, struct kevent_internal_s *kev);
	int     (*f_process)(struct knote *kn, struct filt_process_s *data, struct kevent_internal_s *kev);
	unsigned (*f_peek)(struct knote *kn);
};

struct proc;
struct waitq;

SLIST_HEAD(klist, knote);
extern void	knote_init(void);
extern void	klist_init(struct klist *list);

#define KNOTE(list, hint)	knote(list, hint)
#define KNOTE_ATTACH(list, kn)	knote_attach(list, kn)
#define KNOTE_DETACH(list, kn)	knote_detach(list, kn)


extern void	knote(struct klist *list, long hint);
extern int	knote_attach(struct klist *list, struct knote *kn);
extern int	knote_detach(struct klist *list, struct knote *kn);
extern void knote_vanish(struct klist *list);
extern int	knote_link_waitq(struct knote *kn, struct waitq *wq, uint64_t *reserved_link);
extern int	knote_unlink_waitq(struct knote *kn, struct waitq *wq);
extern void	knote_fdclose(struct proc *p, int fd, int force);
extern void	knote_markstayactive(struct knote *kn);
extern void	knote_clearstayactive(struct knote *kn);
extern void knote_adjust_qos(struct knote *kn, int qos, int override);
extern struct filterops *knote_fops(struct knote *kn);

#elif defined(KERNEL_PRIVATE) /* !XNU_KERNEL_PRIVATE: kexts still need a klist structure definition */

#include <sys/queue.h> 
struct proc;
struct knote;
SLIST_HEAD(klist, knote);

#endif /* !XNU_KERNEL_PRIVATE && KERNEL_PRIVATE */

#ifdef KERNEL_PRIVATE
#ifdef PRIVATE

/* make these private functions available to the pthread kext */
extern int	kevent_qos_internal(struct proc *p, int fd, 
			    user_addr_t changelist, int nchanges,
			    user_addr_t eventlist, int nevents,
			    user_addr_t data_out, user_size_t *data_available,
			    unsigned int flags, int32_t *retval);

extern int  kevent_qos_internal_bind(struct proc *p,
                int fd, thread_t thread, unsigned int flags);
extern int  kevent_qos_internal_unbind(struct proc *p,
                int fd, thread_t thread, unsigned int flags);

#endif  /* PRIVATE */
#endif  /* KERNEL_PRIVATE */

#else 	/* KERNEL */

#include <sys/types.h>

struct timespec;

__BEGIN_DECLS
int     kqueue(void);
int     kevent(int kq, 
	       const struct kevent *changelist, int nchanges,
	       struct kevent *eventlist, int nevents,
	       const struct timespec *timeout);
int     kevent64(int kq, 
		 const struct kevent64_s *changelist, int nchanges,
		 struct kevent64_s *eventlist, int nevents,
		 unsigned int flags, 
		 const struct timespec *timeout);

#ifdef PRIVATE
int     kevent_qos(int kq, 
		   const struct kevent_qos_s *changelist, int nchanges,
		   struct kevent_qos_s *eventlist, int nevents,
		   void *data_out, size_t *data_available,
		   unsigned int flags);
#endif /* PRIVATE */

__END_DECLS


#endif /* KERNEL */


#endif /* !_SYS_EVENT_H_ */