event.h

/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * 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: head/sys/sys/event.h 336457 2018-07-18 13:04:03Z dab $
 */
 
#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_SYSCOUNT     13
 
#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 kevent_freebsd11 {
    __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) && defined(__LP64__))
struct kevent32 {
    uint32_t    ident;      /* identifier for this event */
    short       filter;     /* filter for event */
    u_short     flags;
    u_int       fflags;
#ifndef __amd64__
    uint32_t    pad0;
#endif
    int32_t     data1, data2;
    uint32_t    udata;      /* opaque user data identifier */
#ifndef __amd64__
    uint32_t    pad1;
#endif
    uint32_t    ext64[8];
};
 
#ifdef _WANT_FREEBSD11_KEVENT
struct kevent32_freebsd11 {
    u_int32_t   ident;      /* identifier for this event */
    short       filter;     /* filter for event */
    u_short     flags;
    u_int       fflags;
    int32_t     data;
    u_int32_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 */
 
/* 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 forks */
#define NOTE_TRACKERR   0x00000002      /* could not track child */
#define NOTE_CHILD  0x00000004      /* am a child process */
 
/* 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 */
 
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_locked)(void *);
    void    (*kl_assert_unlocked)(void *);
    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 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);
};
 
/*
 * 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_HASKQLOCK    0x80            /* for _inevent */
#define KN_SCAN     0x100           /* flux set in kqueue_scan() */
    int         kn_influx;
    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 */
        void        *p_v;       /* generic other pointer */
    } kn_ptr;
    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);
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_locked)(void *),
        void (*kl_assert_unlocked)(void *));
void    knlist_init_mtx(struct knlist *knl, struct mtx *lock);
void    knlist_init_rw_reader(struct knlist *knl, struct rwlock *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 waitok);
int kqueue_add_filteropts(int filt, struct filterops *filtops);
int kqueue_del_filteropts(int filt);
 
#else   /* !_KERNEL */
 
#include <sys/cdefs.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);
__END_DECLS
 
#endif /* !_KERNEL */
 
#endif /* !_SYS_EVENT_H_ */