1 /*-
2  * Copyright (c) 2006 Verdens Gang AS
3  * Copyright (c) 2006-2011 Varnish Software AS
4  * All rights reserved.
5  *
6  * Author: Poul-Henning Kamp <phk@phk.freebsd.dk>
7  *
8  * SPDX-License-Identifier: BSD-2-Clause
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  * Waiters are herders of connections:  They monitor a large number of
32  * connections and react if data arrives, the connection is closed or
33  * if nothing happens for a specified timeout period.
34  *
35  * The "poll" waiter should be portable to just about anything, but it
36  * is not very efficient because it has to setup state on each call to
37  * poll(2).  Almost all kernels have made better facilities for that
38  * reason, needless to say, each with its own NIH-controlled API:
39  *
40  * - kqueue on FreeBSD
41  * - epoll on Linux
42  * - ports on Solaris
43  *
44  * Public interfaces
45  */
46 
47 struct waited;
48 struct waiter;
49 
50 enum wait_event {
51 	WAITER_REMCLOSE,
52 	WAITER_TIMEOUT,
53 	WAITER_ACTION,
54 	WAITER_CLOSE
55 };
56 
57 typedef void waiter_handle_f(struct waited *, enum wait_event, vtim_real now);
58 
59 struct waited {
60 	unsigned		magic;
61 #define WAITED_MAGIC		0x1743992d
62 	int			fd;
63 	unsigned		idx;
64 	void			*priv1;
65 	uintptr_t		priv2;
66 	waiter_handle_f		*func;
67 	vtim_dur		tmo;
68 	vtim_real		idle;
69 };
70 
71 /* cache_waiter.c */
72 int Wait_Enter(const struct waiter *, struct waited *);
73 struct waiter *Waiter_New(void);
74 void Waiter_Destroy(struct waiter **);
75 const char *Waiter_GetName(void);
76