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      1 /*	$NetBSD: event.h,v 1.55 2023/07/28 18:19:01 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon (at) FreeBSD.org>
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  *
     28  *	$FreeBSD: src/sys/sys/event.h,v 1.12 2001/02/24 01:44:03 jlemon Exp $
     29  */
     30 
     31 #ifndef _SYS_EVENT_H_
     32 #define	_SYS_EVENT_H_
     33 
     34 #include <sys/featuretest.h>
     35 #include <sys/types.h>			/* for size_t */
     36 #include <sys/inttypes.h>		/* for uintptr_t */
     37 #include <sys/null.h>			/* for NULL */
     38 
     39 #define	EVFILT_READ		0U
     40 #define	EVFILT_WRITE		1U
     41 #define	EVFILT_AIO		2U	/* attached to aio requests */
     42 #define	EVFILT_VNODE		3U	/* attached to vnodes */
     43 #define	EVFILT_PROC		4U	/* attached to struct proc */
     44 #define	EVFILT_SIGNAL		5U	/* attached to struct proc */
     45 #define	EVFILT_TIMER		6U	/* arbitrary timer (in ms) */
     46 #define	EVFILT_FS		7U	/* filesystem events */
     47 #define	EVFILT_USER		8U	/* user events */
     48 #define	EVFILT_EMPTY		9U
     49 #define	EVFILT_SYSCOUNT		10U	/* number of filters */
     50 
     51 #ifdef EVFILT_NAMES
     52 static const char *evfiltnames[] = {
     53 	"EVFILT_READ",
     54 	"EVFILT_WRITE",
     55 	"EVFILT_AIO",
     56 	"EVFILT_VNODE",
     57 	"EVFILT_PROC",
     58 	"EVFILT_SIGNAL",
     59 	"EVFILT_TIMER",
     60 	"EVFILT_FS",
     61 	"EVFILT_USER",
     62 	"EVFILT_EMPTY",
     63 };
     64 #endif
     65 
     66 struct kevent {
     67 	uintptr_t	ident;		/* identifier for this event */
     68 	uint32_t	filter;		/* filter for event */
     69 	uint32_t	flags;		/* action flags for kqueue */
     70 	uint32_t	fflags;		/* filter flag value */
     71 	int64_t		data;		/* filter data value */
     72 	void		*udata;		/* opaque user data identifier */
     73 	uint64_t	ext[4];		/* extensions */
     74 };
     75 
     76 static __inline void
     77 _EV_SET(struct kevent *_kevp, uintptr_t _ident, uint32_t _filter,
     78     uint32_t _flags, uint32_t _fflags, int64_t _data, void *_udata)
     79 {
     80 	_kevp->ident = _ident;
     81 	_kevp->filter = _filter;
     82 	_kevp->flags = _flags;
     83 	_kevp->fflags = _fflags;
     84 	_kevp->data = _data;
     85 	_kevp->udata = _udata;
     86 }
     87 
     88 #define EV_SET(kevp, ident, filter, flags, fflags, data, udata)	\
     89     _EV_SET((kevp), __CAST(uintptr_t, (ident)), (filter), (flags), \
     90     (fflags), (data), __CAST(void *, (udata)))
     91 
     92 /* actions */
     93 #define	EV_ADD		0x0001U		/* add event to kq (implies ENABLE) */
     94 #define	EV_DELETE	0x0002U		/* delete event from kq */
     95 #define	EV_ENABLE	0x0004U		/* enable event */
     96 #define	EV_DISABLE	0x0008U		/* disable event (not reported) */
     97 
     98 /* flags */
     99 #define	EV_ONESHOT	0x0010U		/* only report one occurrence */
    100 #define	EV_CLEAR	0x0020U		/* clear event state after reporting */
    101 #define EV_RECEIPT	0x0040U		/* force EV_ERROR on success, data=0 */
    102 #define EV_DISPATCH	0x0080U		/* disable event after reporting */
    103 
    104 #define	EV_SYSFLAGS	0xF000U		/* reserved by system */
    105 #define	EV_FLAG1	0x2000U		/* filter-specific flag */
    106 
    107 /* returned values */
    108 #define	EV_EOF		0x8000U		/* EOF detected */
    109 #define	EV_ERROR	0x4000U		/* error, data contains errno */
    110 
    111 /*
    112  * data/hint flags/masks for EVFILT_USER, shared with userspace
    113  *
    114  * On input, the top two bits of fflags specifies how the lower twenty four
    115  * bits should be applied to the stored value of fflags.
    116  *
    117  * On output, the top two bits will always be set to NOTE_FFNOP and the
    118  * remaining twenty four bits will contain the stored fflags value.
    119  */
    120 #define	NOTE_FFNOP	0x00000000U		/* ignore input fflags */
    121 #define	NOTE_FFAND	0x40000000U		/* AND fflags */
    122 #define	NOTE_FFOR	0x80000000U		/* OR fflags */
    123 #define	NOTE_FFCOPY	0xc0000000U		/* copy fflags */
    124 
    125 #define	NOTE_FFCTRLMASK	0xc0000000U		/* masks for operations */
    126 #define	NOTE_FFLAGSMASK	0x00ffffffU
    127 
    128 #define	NOTE_TRIGGER	0x01000000U		/* Cause the event to be
    129 						   triggered for output. */
    130 /*
    131  * hint flag for in-kernel use - must not equal any existing note
    132  */
    133 #ifdef _KERNEL
    134 #define NOTE_SUBMIT	0x01000000U		/* initial knote submission */
    135 #endif
    136 /*
    137  * data/hint flags for EVFILT_{READ|WRITE}, shared with userspace
    138  */
    139 #define	NOTE_LOWAT	0x0001U			/* low water mark */
    140 
    141 /*
    142  * data/hint flags for EVFILT_VNODE, shared with userspace
    143  */
    144 #define	NOTE_DELETE	0x0001U			/* vnode was removed */
    145 #define	NOTE_WRITE	0x0002U			/* data contents changed */
    146 #define	NOTE_EXTEND	0x0004U			/* size increased */
    147 #define	NOTE_ATTRIB	0x0008U			/* attributes changed */
    148 #define	NOTE_LINK	0x0010U			/* link count changed */
    149 #define	NOTE_RENAME	0x0020U			/* vnode was renamed */
    150 #define	NOTE_REVOKE	0x0040U			/* vnode access was revoked */
    151 #define	NOTE_OPEN	0x0080U			/* vnode was opened */
    152 #define	NOTE_CLOSE	0x0100U			/* file closed (no FWRITE) */
    153 #define	NOTE_CLOSE_WRITE 0x0200U		/* file closed (FWRITE) */
    154 #define	NOTE_READ	0x0400U			/* file was read */
    155 
    156 /*
    157  * data/hint flags for EVFILT_PROC, shared with userspace
    158  */
    159 #define	NOTE_EXIT	0x80000000U		/* process exited */
    160 #define	NOTE_FORK	0x40000000U		/* process forked */
    161 #define	NOTE_EXEC	0x20000000U		/* process exec'd */
    162 #define	NOTE_PCTRLMASK	0xf0000000U		/* mask for hint bits */
    163 #define	NOTE_PDATAMASK	0x000fffffU		/* mask for pid */
    164 
    165 /* additional flags for EVFILT_PROC */
    166 #define	NOTE_TRACK	0x00000001U		/* follow across forks */
    167 #define	NOTE_TRACKERR	0x00000002U		/* could not track child */
    168 #define	NOTE_CHILD	0x00000004U		/* am a child process */
    169 
    170 /* additional flags for EVFILT_TIMER */
    171 #define	NOTE_MSECONDS	0x00000000U		/* data is milliseconds */
    172 #define	NOTE_SECONDS	0x00000001U		/* data is seconds */
    173 #define	NOTE_USECONDS	0x00000002U		/* data is microseconds */
    174 #define	NOTE_NSECONDS	0x00000003U		/* data is nanoseconds */
    175 #define	NOTE_ABSTIME	0x00000010U		/* timeout is absolute */
    176 #ifdef _KERNEL
    177 #define	NOTE_TIMER_UNITMASK 0x0003U
    178 #endif /* _KERNEL */
    179 
    180 /*
    181  * This is currently visible to userland to work around broken
    182  * programs which pull in <sys/proc.h> or <sys/select.h>.
    183  */
    184 #include <sys/queue.h>
    185 struct knote;
    186 SLIST_HEAD(klist, knote);
    187 
    188 
    189 /*
    190  * ioctl(2)s supported on kqueue descriptors.
    191  */
    192 #include <sys/ioctl.h>
    193 
    194 struct kfilter_mapping {
    195 	char		*name;		/* name to lookup or return */
    196 	size_t		len;		/* length of name */
    197 	uint32_t	filter;		/* filter to lookup or return */
    198 };
    199 
    200 /* map filter to name (max size len) */
    201 #define KFILTER_BYFILTER	_IOWR('k', 0, struct kfilter_mapping)
    202 /* map name to filter (len ignored) */
    203 #define KFILTER_BYNAME		_IOWR('k', 1, struct kfilter_mapping)
    204 
    205 #ifdef _KERNEL
    206 
    207 #define	KNOTE(list, hint)	if (!SLIST_EMPTY(list)) knote(list, hint)
    208 
    209 /*
    210  * Flag indicating hint is a signal.  Used by EVFILT_SIGNAL, and also
    211  * shared by EVFILT_PROC  (all knotes attached to p->p_klist)
    212  */
    213 #define	NOTE_SIGNAL	0x08000000U
    214 
    215 /*
    216  * Hint values for the optional f_touch event filter.  If f_touch is not set
    217  * to NULL and f_isfd is zero the f_touch filter will be called with the type
    218  * argument set to EVENT_REGISTER during a kevent() system call.  It is also
    219  * called under the same conditions with the type argument set to EVENT_PROCESS
    220  * when the event has been triggered.
    221  */
    222 #define	EVENT_REGISTER	1
    223 #define	EVENT_PROCESS	2
    224 
    225 /*
    226  * Callback methods for each filter type.
    227  */
    228 struct filterops {
    229 	int	f_flags;		/* flags; see below */
    230 	int	(*f_attach)	(struct knote *);
    231 					/* called when knote is ADDed */
    232 	void	(*f_detach)	(struct knote *);
    233 					/* called when knote is DELETEd */
    234 	int	(*f_event)	(struct knote *, long);
    235 					/* called when event is triggered */
    236 	int	(*f_touch)	(struct knote *, struct kevent *, long);
    237 };
    238 
    239 /* filterops flags */
    240 #define	FILTEROP_ISFD	__BIT(0)	/* ident == file descriptor */
    241 #define	FILTEROP_MPSAFE	__BIT(1)	/* does not require KERNEL_LOCK */
    242 
    243 /*
    244  * Field locking:
    245  *
    246  * f	kn_kq->kq_fdp->fd_lock
    247  * q	kn_kq->kq_lock
    248  * o	object mutex (e.g. device driver or vnode interlock)
    249  */
    250 struct kfilter;
    251 
    252 struct knote {
    253 	SLIST_ENTRY(knote)	kn_link;	/* f: for fd */
    254 	SLIST_ENTRY(knote)	kn_selnext;	/* o: for struct selinfo */
    255 	TAILQ_ENTRY(knote)	kn_tqe;		/* q: for struct kqueue */
    256 	struct kqueue		*kn_kq;		/* q: which queue we are on */
    257 	struct kevent		kn_kevent;	/* (see below for locking) */
    258 	uint32_t		kn_status;	/* q: flags below */
    259 	uint32_t		kn_sfflags;	/*    saved filter flags */
    260 	uintptr_t		kn_sdata;	/*    saved data field */
    261 	void			*kn_obj;	/*    monitored obj */
    262 	const struct filterops	*kn_fop;
    263 	struct kfilter		*kn_kfilter;
    264 	void 			*kn_hook;
    265 	int			kn_hookid;
    266 
    267 #define	KN_ACTIVE	0x01U			/* event has been triggered */
    268 #define	KN_QUEUED	0x02U			/* event is on queue */
    269 #define	KN_DISABLED	0x04U			/* event is disabled */
    270 #define	KN_DETACHED	0x08U			/* knote is detached */
    271 #define	KN_MARKER	0x10U			/* is a marker */
    272 #define	KN_BUSY		0x20U			/* is being scanned */
    273 #define	KN_WILLDETACH	0x40U			/* being detached imminently */
    274 /* Toggling KN_BUSY also requires kn_kq->kq_fdp->fd_lock. */
    275 #define __KN_FLAG_BITS \
    276     "\20" \
    277     "\1ACTIVE" \
    278     "\2QUEUED" \
    279     "\3DISABLED" \
    280     "\4DETACHED" \
    281     "\5MARKER" \
    282     "\6BUSY" \
    283     "\7WILLDETACH"
    284 
    285 
    286 /*
    287  * The only time knote::kn_flags can be modified without synchronization
    288  * is during filter attach, because the knote has not yet been published.
    289  * This is usually to set EV_CLEAR or EV_ONESHOT as mandatory flags for
    290  * that filter.
    291  */
    292 #define	kn_id		kn_kevent.ident
    293 #define	kn_filter	kn_kevent.filter
    294 #define	kn_flags	kn_kevent.flags		/* q */
    295 #define	kn_fflags	kn_kevent.fflags	/* o */
    296 #define	kn_data		kn_kevent.data		/* o */
    297 };
    298 
    299 #include <sys/systm.h>	/* for copyin_t */
    300 
    301 struct lwp;
    302 struct timespec;
    303 
    304 void	kqueue_init(void);
    305 void	knote(struct klist *, long);
    306 void	knote_fdclose(int);
    307 void	knote_set_eof(struct knote *, uint32_t);
    308 void	knote_clear_eof(struct knote *);
    309 
    310 typedef	int (*kevent_fetch_changes_t)(void *, const struct kevent *,
    311     struct kevent *, size_t, int);
    312 typedef	int (*kevent_put_events_t)(void *, struct kevent *, struct kevent *,
    313     size_t, int);
    314 
    315 struct kevent_ops {
    316 	void *keo_private;
    317 	copyin_t keo_fetch_timeout;
    318 	kevent_fetch_changes_t keo_fetch_changes;
    319 	kevent_put_events_t keo_put_events;
    320 };
    321 
    322 
    323 int	kevent_fetch_changes(void *, const struct kevent *, struct kevent *,
    324     size_t, int);
    325 int 	kevent_put_events(void *, struct kevent *, struct kevent *, size_t,
    326     int);
    327 int	kevent1(register_t *, int, const struct kevent *,
    328     size_t, struct kevent *, size_t, const struct timespec *,
    329     const struct kevent_ops *);
    330 
    331 int	kfilter_register(const char *, const struct filterops *, int *);
    332 int	kfilter_unregister(const char *);
    333 
    334 int	filt_seltrue(struct knote *, long);
    335 extern const struct filterops seltrue_filtops;
    336 
    337 void	klist_init(struct klist *);
    338 void	klist_fini(struct klist *);
    339 void	klist_insert(struct klist *, struct knote *);
    340 bool	klist_remove(struct klist *, struct knote *);
    341 
    342 #else 	/* !_KERNEL */
    343 
    344 #include <sys/cdefs.h>
    345 struct timespec;
    346 
    347 __BEGIN_DECLS
    348 #if defined(_NETBSD_SOURCE)
    349 int	kqueue(void);
    350 int	kqueue1(int);
    351 #ifndef __LIBC12_SOURCE__
    352 int	kevent(int, const struct kevent *, size_t, struct kevent *, size_t,
    353 		    const struct timespec *) __RENAME(__kevent100);
    354 #endif
    355 #endif /* !_POSIX_C_SOURCE */
    356 __END_DECLS
    357 
    358 #endif /* !_KERNEL */
    359 
    360 #endif /* !_SYS_EVENT_H_ */
    361