/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * 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.
 */

#ifndef _SYS_EVENT_H_
#define _SYS_EVENT_H_

#include <sys/_types.h>
#include <sys/queue.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_PROCDESC         (-8)    /* attached to process descriptors */
#define EVFILT_FS               (-9)    /* filesystem events */
#define EVFILT_LIO              (-10)   /* attached to lio requests */
#define EVFILT_USER             (-11)   /* User events */
#define EVFILT_SENDFILE         (-12)   /* attached to sendfile requests */
#define EVFILT_EMPTY            (-13)   /* empty send socket buf */
#define EVFILT_JAIL             (-14)   /* attached to struct prison */
#define EVFILT_JAILDESC         (-15)   /* attached to jail descriptors */
#define EVFILT_SYSCOUNT         15

#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
#define EV_SET(kevp_, a, b, c, d, e, f) do {    \
        *(kevp_) = (struct kevent){             \
            .ident = (a),                       \
            .filter = (b),                      \
            .flags = (c),                       \
            .fflags = (d),                      \
            .data = (e),                        \
            .udata = (f),                       \
            .ext = {0},                         \
        };                                      \
} while (0)
#else /* Pre-C99 or not STDC (e.g., C++) */
/*
 * The definition of the local variable kevp could possibly conflict
 * with a user-defined value passed in parameters a-f.
 */
#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);                    \
        (kevp)->ext[0] = 0;                     \
        (kevp)->ext[1] = 0;                     \
        (kevp)->ext[2] = 0;                     \
        (kevp)->ext[3] = 0;                     \
} while (0)
#endif

struct kevent {
        __uintptr_t     ident;          /* identifier for this event */
        short           filter;         /* filter for event */
        unsigned short  flags;          /* action flags for kqueue */
        unsigned int    fflags;         /* filter flag value */
        __int64_t       data;           /* filter data value */
        void            *udata;         /* opaque user data identifier */
        __uint64_t      ext[4];         /* extensions */
};

#if defined(_WANT_FREEBSD11_KEVENT)
/* Older structure used in FreeBSD 11.x and older. */
struct freebsd11_kevent {
        __uintptr_t     ident;          /* identifier for this event */
        short           filter;         /* filter for event */
        unsigned short  flags;
        unsigned int    fflags;
        __intptr_t      data;
        void            *udata;         /* opaque user data identifier */
};
#endif

#if defined(_WANT_KEVENT32) || defined(_KERNEL)
#include <sys/abi_types.h>

struct kevent32 {
        __uint32_t      ident;          /* identifier for this event */
        short           filter;         /* filter for event */
        unsigned short  flags;
        unsigned int    fflags;
#ifndef __amd64__
        __uint32_t      pad0;
#endif
        freebsd32_uint64_t data;
        __uint32_t      udata;          /* opaque user data identifier */
#ifndef __amd64__
        __uint32_t      pad1;
#endif
        freebsd32_uint64_t ext[4];
};

#ifdef _WANT_FREEBSD11_KEVENT
struct freebsd11_kevent32 {
        __uint32_t      ident;          /* identifier for this event */
        short           filter;         /* filter for event */
        unsigned short  flags;
        unsigned int    fflags;
        __int32_t       data;
        __uint32_t      udata;          /* opaque user data identifier */
};
#endif
#endif

/* 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) */
#define EV_FORCEONESHOT 0x0100          /* enable _ONESHOT and force trigger */
#define EV_KEEPUDATA    0x0200          /* do not update the udata field */

/* flags */
#define EV_ONESHOT      0x0010          /* only report one occurrence */
#define EV_CLEAR        0x0020          /* clear event state after reporting */
#define EV_RECEIPT      0x0040          /* force EV_ERROR on success, data=0 */
#define EV_DISPATCH     0x0080          /* disable event after reporting */

#define EV_SYSFLAGS     0xF000          /* reserved by system */
#define EV_DROP         0x1000          /* note should be dropped */
#define EV_FLAG1        0x2000          /* filter-specific flag */
#define EV_FLAG2        0x4000          /* filter-specific flag */

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

 /*
  * data/hint flags/masks for EVFILT_USER, shared with userspace
  *
  * 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              /* masks for operations */
#define NOTE_FFLAGSMASK 0x00ffffff

#define NOTE_TRIGGER    0x01000000              /* Cause the event to be
                                                   triggered for output. */

/*
 * data/hint flags for EVFILT_{READ|WRITE}, shared with userspace
 */
#define NOTE_LOWAT      0x0001                  /* low water mark */
#define NOTE_FILE_POLL  0x0002                  /* behave like poll() */

/*
 * data/hint flags for EVFILT_VNODE, shared with userspace
 */
#define NOTE_DELETE     0x0001                  /* vnode was removed */
#define NOTE_WRITE      0x0002                  /* data contents changed */
#define NOTE_EXTEND     0x0004                  /* size increased */
#define NOTE_ATTRIB     0x0008                  /* attributes changed */
#define NOTE_LINK       0x0010                  /* link count changed */
#define NOTE_RENAME     0x0020                  /* vnode was renamed */
#define NOTE_REVOKE     0x0040                  /* vnode access was revoked */
#define NOTE_OPEN       0x0080                  /* vnode was opened */
#define NOTE_CLOSE      0x0100                  /* file closed, fd did not
                                                   allowed write */
#define NOTE_CLOSE_WRITE 0x0200                 /* file closed, fd did allowed
                                                   write */
#define NOTE_READ       0x0400                  /* file was read */

/*
 * data/hint flags for EVFILT_PROC and EVFILT_PROCDESC, shared with userspace
 */
#define NOTE_EXIT       0x80000000              /* process exited */
#define NOTE_FORK       0x40000000              /* process forked */
#define NOTE_EXEC       0x20000000              /* process exec'd */
#define NOTE_PCTRLMASK  0xf0000000              /* mask for hint bits */
#define NOTE_PDATAMASK  0x000fffff              /* mask for pid */

/* additional flags for EVFILT_PROC */
#define NOTE_TRACK      0x00000001              /* follow across fork/create */
#define NOTE_TRACKERR   0x00000002              /* could not track child */
#define NOTE_CHILD      0x00000004              /* am a child process */

/* data/hint flags for EVFILT_JAIL and EVFILT_JAILDESC */
#define NOTE_JAIL_CHILD         0x80000000      /* child jail was created */
#define NOTE_JAIL_SET           0x40000000      /* jail was modified */
#define NOTE_JAIL_ATTACH        0x20000000      /* jail was attached to */
#define NOTE_JAIL_REMOVE        0x10000000      /* jail was removed */
#define NOTE_JAIL_MULTI         0x08000000      /* multiple child or attach */
#define NOTE_JAIL_CTRLMASK      0xf0000000      /* mask for hint bits */

/* additional flags for EVFILT_TIMER */
#define NOTE_SECONDS            0x00000001      /* data is seconds */
#define NOTE_MSECONDS           0x00000002      /* data is milliseconds */
#define NOTE_USECONDS           0x00000004      /* data is microseconds */
#define NOTE_NSECONDS           0x00000008      /* data is nanoseconds */
#define NOTE_ABSTIME            0x00000010      /* timeout is absolute */

/* Flags for kqueuex(2) */
#define KQUEUE_CLOEXEC  0x00000001      /* close on exec */
#define KQUEUE_CPONFORK 0x00000002      /* copy on fork */

struct knote;
SLIST_HEAD(klist, knote);
struct kqueue;
TAILQ_HEAD(kqlist, kqueue);
struct knlist {
        struct  klist   kl_list;
        void    (*kl_lock)(void *);     /* lock function */
        void    (*kl_unlock)(void *);
        void    (*kl_assert_lock)(void *, int);
        void    *kl_lockarg;            /* argument passed to lock functions */
        int     kl_autodestroy;
};

#ifdef _KERNEL

/*
 * Flags for knote call
 */
#define KNF_LISTLOCKED  0x0001                  /* knlist is locked */
#define KNF_NOKQLOCK    0x0002                  /* do not keep KQ_LOCK */

#define KNOTE(list, hint, flags)        knote(list, hint, flags)
#define KNOTE_LOCKED(list, hint)        knote(list, hint, KNF_LISTLOCKED)
#define KNOTE_UNLOCKED(list, hint)      knote(list, hint, 0)

#define KNLIST_EMPTY(list)              SLIST_EMPTY(&(list)->kl_list)

/*
 * Flag indicating hint is a signal.  Used by EVFILT_SIGNAL, and also
 * shared by EVFILT_PROC  (all knotes attached to p->p_klist)
 */
#define NOTE_SIGNAL     0x08000000

/*
 * Hint values for the optional f_touch event filter.  If f_touch is not set 
 * to NULL and f_isfd is zero the f_touch filter will be called with the type
 * argument set to EVENT_REGISTER during a kevent() system call.  It is also
 * called under the same conditions with the type argument set to EVENT_PROCESS
 * when the event has been triggered.
 */
#define EVENT_REGISTER  1
#define EVENT_PROCESS   2

struct kinfo_knote;
struct proc;

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);
        void    (*f_touch)(struct knote *kn, struct kevent *kev, u_long type);
        int     (*f_userdump)(struct proc *p, struct knote *kn,
                    struct kinfo_knote *kin);
        int     (*f_copy)(struct knote *kn, struct proc *p1);
};

/*
 * An in-flux knote cannot be dropped from its kq while the kq is
 * unlocked.  If the KN_SCAN flag is not set, a thread can only set
 * kn_influx when it is exclusive owner of the knote state, and can
 * modify kn_status as if it had the KQ lock.  KN_SCAN must not be set
 * on a knote which is already in flux.
 *
 * kn_sfflags, kn_sdata, and kn_kevent are protected by the knlist lock.
 */
struct knote {
        SLIST_ENTRY(knote)      kn_link;        /* for kq */
        SLIST_ENTRY(knote)      kn_selnext;     /* for struct selinfo */
        struct                  knlist *kn_knlist;      /* f_attach populated */
        TAILQ_ENTRY(knote)      kn_tqe;
        struct                  kqueue *kn_kq;  /* which queue we are on */
        struct                  kevent kn_kevent;
        void                    *kn_hook;
        int                     kn_hookid;
        int                     kn_status;      /* protected by kq lock */
#define KN_ACTIVE       0x01                    /* event has been triggered */
#define KN_QUEUED       0x02                    /* event is on queue */
#define KN_DISABLED     0x04                    /* event is disabled */
#define KN_DETACHED     0x08                    /* knote is detached */
#define KN_MARKER       0x20                    /* ignore this knote */
#define KN_KQUEUE       0x40                    /* this knote belongs to a kq */
#define KN_SCAN         0x100                   /* flux set in kqueue_scan() */
        int                     kn_influx;
        unsigned int            kn_sfflags;     /* saved filter flags */
        int64_t                 kn_sdata;       /* saved data field */
        union {
                struct          file *p_fp;     /* file data pointer */
                struct          proc *p_proc;   /* proc pointer */
                struct          kaiocb *p_aio;  /* AIO job pointer */
                struct          aioliojob *p_lio;       /* LIO job pointer */
                struct          prison *p_prison;       /* prison pointer */
                void            *p_v;           /* generic other pointer */
        } kn_ptr;
        const struct            filterops *kn_fop;

#define kn_id           kn_kevent.ident
#define kn_filter       kn_kevent.filter
#define kn_flags        kn_kevent.flags
#define kn_fflags       kn_kevent.fflags
#define kn_data         kn_kevent.data
#define kn_fp           kn_ptr.p_fp
};
struct kevent_copyops {
        void    *arg;
        int     (*k_copyout)(void *arg, struct kevent *kevp, int count);
        int     (*k_copyin)(void *arg, struct kevent *kevp, int count);
        size_t  kevent_size;
};

struct thread;
struct proc;
struct knlist;
struct mtx;
struct rwlock;

void    knote(struct knlist *list, long hint, int lockflags);
void    knote_fork(struct knlist *list, int pid);
int     knote_triv_copy(struct knote *kn, struct proc *p1);
struct knlist *knlist_alloc(struct mtx *lock);
void    knlist_detach(struct knlist *knl);
void    knlist_add(struct knlist *knl, struct knote *kn, int islocked);
void    knlist_remove(struct knlist *knl, struct knote *kn, int islocked);
int     knlist_empty(struct knlist *knl);
void    knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *),
            void (*kl_unlock)(void *), void (*kl_assert_lock)(void *, int));
void    knlist_init_mtx(struct knlist *knl, struct mtx *lock);
void    knlist_destroy(struct knlist *knl);
void    knlist_cleardel(struct knlist *knl, struct thread *td,
            int islocked, int killkn);
#define knlist_clear(knl, islocked)                             \
        knlist_cleardel((knl), NULL, (islocked), 0)
#define knlist_delete(knl, td, islocked)                        \
        knlist_cleardel((knl), (td), (islocked), 1)
void    knote_fdclose(struct thread *p, int fd);
int     kqfd_register(int fd, struct kevent *kev, struct thread *p,
            int mflag);
int     kqueue_add_filteropts(int filt, const struct filterops *filtops);
int     kqueue_del_filteropts(int filt);
void    kqueue_drain_schedtask(void);

#else   /* !_KERNEL */

#include <sys/cdefs.h>
struct timespec;

__BEGIN_DECLS
int     kqueue(void);
int     kqueuex(unsigned flags);
int     kqueue1(int flags);
int     kevent(int kq, const struct kevent *changelist, int nchanges,
            struct kevent *eventlist, int nevents,
            const struct timespec *timeout);
__END_DECLS

#endif /* !_KERNEL */

#endif /* !_SYS_EVENT_H_ */