/*      $NetBSD: eventvar.h,v 1.10 2021/10/10 18:07:51 thorpej Exp $    */

/*-
 * Copyright (c) 1999,2000 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/eventvar.h,v 1.4 2000/07/18 19:31:48 jlemon Exp
 */

/*
 * This header is provided for the kqueue implementation and kmem
 * grovellers, and is not expected to be used elsewhere.
 */

#ifndef _SYS_EVENTVAR_H_
#define _SYS_EVENTVAR_H_

#include <sys/mutex.h>
#include <sys/selinfo.h>
#include <sys/filedesc.h>

#define KQ_NEVENTS      8               /* minimize copy{in,out} calls */
#define KQ_EXTENT       256             /* linear growth by this amount */
#define KFILTER_MAXNAME 256             /* maximum size of a filter name */
#define KFILTER_EXTENT  8               /* grow user_kfilters by this amt */

struct kqueue {
        TAILQ_HEAD(kqlist, knote) kq_head;      /* list of pending event */
        kmutex_t        kq_lock;                /* mutex for queue access */
        filedesc_t      *kq_fdp;
        struct selinfo  kq_sel;
        kcondvar_t      kq_cv;
        uint32_t        kq_count;               /* number of pending events */
};

#define KQ_RESTART      __BIT(31)               /* force ERESTART */
#define KQ_CLOSING      __BIT(30)               /* kqueue is closing for good */
#define KQ_MAXCOUNT     __BITS(0,29)
#define KQ_COUNT(kq)    ((unsigned int)((kq)->kq_count & KQ_MAXCOUNT))

#ifdef _KERNEL

#if defined(DDB)
void    kqueue_printit(struct kqueue *, bool,
            void (*)(const char *, ...));
#endif /* DDB */

#endif /* _KERNEL */

#endif /* !_SYS_EVENTVAR_H_ */