event.h revision 1.43 
1/*	$NetBSD: event.h,v 1.43 2021/09/26 21:29:39 thorpej Exp $	*/
2
3/*-
4 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@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_SYSCOUNT		9U	/* number of filters */
49
50#ifdef EVFILT_NAMES
51static const char *evfiltnames[] = {
52	"EVFILT_READ",
53	"EVFILT_WRITE",
54	"EVFILT_AIO",
55	"EVFILT_VNODE",
56	"EVFILT_PROC",
57	"EVFILT_SIGNAL",
58	"EVFILT_TIMER",
59	"EVFILT_FS",
60	"EVFILT_USER",
61};
62#endif
63
64struct kevent {
65	uintptr_t	ident;		/* identifier for this event */
66	uint32_t	filter;		/* filter for event */
67	uint32_t	flags;		/* action flags for kqueue */
68	uint32_t	fflags;		/* filter flag value */
69	int64_t		data;		/* filter data value */
70	void		*udata;		/* opaque user data identifier */
71};
72
73static __inline void
74_EV_SET(struct kevent *_kevp, uintptr_t _ident, uint32_t _filter,
75    uint32_t _flags, uint32_t _fflags, int64_t _data, void *_udata)
76{
77	_kevp->ident = _ident;
78	_kevp->filter = _filter;
79	_kevp->flags = _flags;
80	_kevp->fflags = _fflags;
81	_kevp->data = _data;
82	_kevp->udata = _udata;
83}
84
85#define EV_SET(kevp, ident, filter, flags, fflags, data, udata)	\
86    _EV_SET((kevp), __CAST(uintptr_t, (ident)), (filter), (flags), \
87    (fflags), (data), __CAST(void *, (udata)))
88
89/* actions */
90#define	EV_ADD		0x0001U		/* add event to kq (implies ENABLE) */
91#define	EV_DELETE	0x0002U		/* delete event from kq */
92#define	EV_ENABLE	0x0004U		/* enable event */
93#define	EV_DISABLE	0x0008U		/* disable event (not reported) */
94
95/* flags */
96#define	EV_ONESHOT	0x0010U		/* only report one occurrence */
97#define	EV_CLEAR	0x0020U		/* clear event state after reporting */
98#define EV_RECEIPT	0x0040U		/* force EV_ERROR on success, data=0 */
99#define EV_DISPATCH	0x0080U		/* disable event after reporting */
100
101#define	EV_SYSFLAGS	0xF000U		/* reserved by system */
102#define	EV_FLAG1	0x2000U		/* filter-specific flag */
103
104/* returned values */
105#define	EV_EOF		0x8000U		/* EOF detected */
106#define	EV_ERROR	0x4000U		/* error, data contains errno */
107
108/*
109 * data/hint flags/masks for EVFILT_USER, shared with userspace
110 *
111 * On input, the top two bits of fflags specifies how the lower twenty four
112 * bits should be applied to the stored value of fflags.
113 *
114 * On output, the top two bits will always be set to NOTE_FFNOP and the
115 * remaining twenty four bits will contain the stored fflags value.
116 */
117#define	NOTE_FFNOP	0x00000000U		/* ignore input fflags */
118#define	NOTE_FFAND	0x40000000U		/* AND fflags */
119#define	NOTE_FFOR	0x80000000U		/* OR fflags */
120#define	NOTE_FFCOPY	0xc0000000U		/* copy fflags */
121
122#define	NOTE_FFCTRLMASK	0xc0000000U		/* masks for operations */
123#define	NOTE_FFLAGSMASK	0x00ffffffU
124
125#define	NOTE_TRIGGER	0x01000000U		/* Cause the event to be
126						   triggered for output. */
127/*
128 * hint flag for in-kernel use - must not equal any existing note
129 */
130#ifdef _KERNEL
131#define NOTE_SUBMIT	0x01000000U		/* initial knote submission */
132#endif
133/*
134 * data/hint flags for EVFILT_{READ|WRITE}, shared with userspace
135 */
136#define	NOTE_LOWAT	0x0001U			/* low water mark */
137
138/*
139 * data/hint flags for EVFILT_VNODE, shared with userspace
140 */
141#define	NOTE_DELETE	0x0001U			/* vnode was removed */
142#define	NOTE_WRITE	0x0002U			/* data contents changed */
143#define	NOTE_EXTEND	0x0004U			/* size increased */
144#define	NOTE_ATTRIB	0x0008U			/* attributes changed */
145#define	NOTE_LINK	0x0010U			/* link count changed */
146#define	NOTE_RENAME	0x0020U			/* vnode was renamed */
147#define	NOTE_REVOKE	0x0040U			/* vnode access was revoked */
148
149/*
150 * data/hint flags for EVFILT_PROC, shared with userspace
151 */
152#define	NOTE_EXIT	0x80000000U		/* process exited */
153#define	NOTE_FORK	0x40000000U		/* process forked */
154#define	NOTE_EXEC	0x20000000U		/* process exec'd */
155#define	NOTE_PCTRLMASK	0xf0000000U		/* mask for hint bits */
156#define	NOTE_PDATAMASK	0x000fffffU		/* mask for pid */
157
158/* additional flags for EVFILT_PROC */
159#define	NOTE_TRACK	0x00000001U		/* follow across forks */
160#define	NOTE_TRACKERR	0x00000002U		/* could not track child */
161#define	NOTE_CHILD	0x00000004U		/* am a child process */
162
163/*
164 * This is currently visible to userland to work around broken
165 * programs which pull in <sys/proc.h> or <sys/select.h>.
166 */
167#include <sys/queue.h>
168struct knote;
169SLIST_HEAD(klist, knote);
170
171
172/*
173 * ioctl(2)s supported on kqueue descriptors.
174 */
175#include <sys/ioctl.h>
176
177struct kfilter_mapping {
178	char		*name;		/* name to lookup or return */
179	size_t		len;		/* length of name */
180	uint32_t	filter;		/* filter to lookup or return */
181};
182
183/* map filter to name (max size len) */
184#define KFILTER_BYFILTER	_IOWR('k', 0, struct kfilter_mapping)
185/* map name to filter (len ignored) */
186#define KFILTER_BYNAME		_IOWR('k', 1, struct kfilter_mapping)
187
188#ifdef _KERNEL
189
190#define	KNOTE(list, hint)	if (!SLIST_EMPTY(list)) knote(list, hint)
191
192/*
193 * Flag indicating hint is a signal.  Used by EVFILT_SIGNAL, and also
194 * shared by EVFILT_PROC  (all knotes attached to p->p_klist)
195 */
196#define	NOTE_SIGNAL	0x08000000U
197
198/*
199 * Hint values for the optional f_touch event filter.  If f_touch is not set
200 * to NULL and f_isfd is zero the f_touch filter will be called with the type
201 * argument set to EVENT_REGISTER during a kevent() system call.  It is also
202 * called under the same conditions with the type argument set to EVENT_PROCESS
203 * when the event has been triggered.
204 */
205#define	EVENT_REGISTER	1
206#define	EVENT_PROCESS	2
207
208/*
209 * Callback methods for each filter type.
210 */
211struct filterops {
212	int	f_flags;		/* flags; see below */
213	int	(*f_attach)	(struct knote *);
214					/* called when knote is ADDed */
215	void	(*f_detach)	(struct knote *);
216					/* called when knote is DELETEd */
217	int	(*f_event)	(struct knote *, long);
218					/* called when event is triggered */
219	void	(*f_touch)	(struct knote *, struct kevent *, long);
220};
221
222/* filterops flags */
223#define	FILTEROP_ISFD	__BIT(0)	/* ident == file descriptor */
224#define	FILTEROP_MPSAFE	__BIT(1)	/* does not require KERNEL_LOCK */
225
226/*
227 * Field locking:
228 *
229 * f	kn_kq->kq_fdp->fd_lock
230 * q	kn_kq->kq_lock
231 * o	object mutex (e.g. device driver or vnode interlock)
232 */
233struct kfilter;
234
235struct knote {
236	SLIST_ENTRY(knote)	kn_link;	/* f: for fd */
237	SLIST_ENTRY(knote)	kn_selnext;	/* o: for struct selinfo */
238	TAILQ_ENTRY(knote)	kn_tqe;		/* q: for struct kqueue */
239	struct kqueue		*kn_kq;		/* q: which queue we are on */
240	struct kevent		kn_kevent;
241	uint32_t		kn_status;	/* q: flags below */
242	uint32_t		kn_sfflags;	/*    saved filter flags */
243	uintptr_t		kn_sdata;	/*    saved data field */
244	void			*kn_obj;	/*    monitored obj */
245	const struct filterops	*kn_fop;
246	struct kfilter		*kn_kfilter;
247	void 			*kn_hook;
248	int			kn_hookid;
249
250#define	KN_ACTIVE	0x01U			/* event has been triggered */
251#define	KN_QUEUED	0x02U			/* event is on queue */
252#define	KN_DISABLED	0x04U			/* event is disabled */
253#define	KN_DETACHED	0x08U			/* knote is detached */
254#define	KN_MARKER	0x10U			/* is a marker */
255#define	KN_BUSY		0x20U			/* is being scanned */
256/* Toggling KN_BUSY also requires kn_kq->kq_fdp->fd_lock. */
257#define __KN_FLAG_BITS \
258    "\20" \
259    "\1ACTIVE" \
260    "\2QUEUED" \
261    "\3DISABLED" \
262    "\4DETACHED" \
263    "\5MARKER" \
264    "\6BUSY"
265
266
267#define	kn_id		kn_kevent.ident
268#define	kn_filter	kn_kevent.filter
269#define	kn_flags	kn_kevent.flags
270#define	kn_fflags	kn_kevent.fflags
271#define	kn_data		kn_kevent.data
272};
273
274#include <sys/systm.h>	/* for copyin_t */
275
276struct lwp;
277struct timespec;
278
279void	kqueue_init(void);
280void	knote(struct klist *, long);
281void	knote_fdclose(int);
282
283typedef	int (*kevent_fetch_changes_t)(void *, const struct kevent *,
284    struct kevent *, size_t, int);
285typedef	int (*kevent_put_events_t)(void *, struct kevent *, struct kevent *,
286    size_t, int);
287
288struct kevent_ops {
289	void *keo_private;
290	copyin_t keo_fetch_timeout;
291	kevent_fetch_changes_t keo_fetch_changes;
292	kevent_put_events_t keo_put_events;
293};
294
295
296int	kevent_fetch_changes(void *, const struct kevent *, struct kevent *,
297    size_t, int);
298int 	kevent_put_events(void *, struct kevent *, struct kevent *, size_t,
299    int);
300int	kevent1(register_t *, int, const struct kevent *,
301    size_t, struct kevent *, size_t, const struct timespec *,
302    const struct kevent_ops *);
303
304int	kfilter_register(const char *, const struct filterops *, int *);
305int	kfilter_unregister(const char *);
306
307int	filt_seltrue(struct knote *, long);
308extern const struct filterops seltrue_filtops;
309
310#else 	/* !_KERNEL */
311
312#include <sys/cdefs.h>
313struct timespec;
314
315__BEGIN_DECLS
316#if defined(_NETBSD_SOURCE)
317int	kqueue(void);
318int	kqueue1(int);
319#ifndef __LIBC12_SOURCE__
320int	kevent(int, const struct kevent *, size_t, struct kevent *, size_t,
321		    const struct timespec *) __RENAME(__kevent50);
322#endif
323#endif /* !_POSIX_C_SOURCE */
324__END_DECLS
325
326#endif /* !_KERNEL */
327
328#endif /* !_SYS_EVENT_H_ */
329