summaryrefslogtreecommitdiffstats
path: root/contrib/unbound/util/mini_event.h
blob: 248468ada84ab3eb39f8527ae53c495bc559b574 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
/*
 * mini-event.h - micro implementation of libevent api, using select() only.
 *
 * Copyright (c) 2007, NLnet Labs. All rights reserved.
 * 
 * This software is open source.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 
 * 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.
 * 
 * Neither the name of the NLNET LABS nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 REGENTS 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.
 */

/**
 * \file
 * This file implements part of the event(3) libevent api.
 * The back end is only select. Max number of fds is limited.
 * Max number of signals is limited, one handler per signal only.
 * And one handler per fd.
 *
 * Although limited to select() and a max (1024) open fds, it
 * is efficient:
 * o dispatch call caches fd_sets to use. 
 * o handler calling takes time ~ to the number of fds.
 * o timeouts are stored in a redblack tree, sorted, so take log(n).
 * Timeouts are only accurate to the second (no subsecond accuracy).
 * To avoid cpu hogging, fractional timeouts are rounded up to a whole second.
 */

#ifndef MINI_EVENT_H
#define MINI_EVENT_H

#if defined(USE_MINI_EVENT) && !defined(USE_WINSOCK)

#ifndef HAVE_EVENT_BASE_FREE
#define HAVE_EVENT_BASE_FREE
#endif 

/** event timeout */
#define EV_TIMEOUT	0x01
/** event fd readable */
#define EV_READ		0x02
/** event fd writable */
#define EV_WRITE	0x04
/** event signal */
#define EV_SIGNAL	0x08
/** event must persist */
#define EV_PERSIST	0x10

/* needs our redblack tree */
#include "rbtree.h"

/** max number of file descriptors to support */
#define MAX_FDS 1024
/** max number of signals to support */
#define MAX_SIG 32

/** event base */
struct event_base
{
	/** sorted by timeout (absolute), ptr */
	rbtree_t* times;
	/** array of 0 - maxfd of ptr to event for it */
	struct event** fds;
	/** max fd in use */
	int maxfd;
	/** capacity - size of the fds array */
	int capfd;
	/* fdset for read write, for fds ready, and added */
	fd_set 
		/** fds for reading */
		reads, 
		/** fds for writing */
		writes, 
		/** fds determined ready for use */
		ready, 
		/** ready plus newly added events. */
		content;
	/** array of 0 - maxsig of ptr to event for it */
	struct event** signals;
	/** if we need to exit */
	int need_to_exit;
	/** where to store time in seconds */
	uint32_t* time_secs;
	/** where to store time in microseconds */
	struct timeval* time_tv;
};

/**
 * Event structure. Has some of the event elements.
 */
struct event {
	/** node in timeout rbtree */
	rbnode_t node;
	/** is event already added */
	int added;

	/** event base it belongs to */
	struct event_base *ev_base;
	/** fd to poll or -1 for timeouts. signal number for sigs. */
	int ev_fd;
	/** what events this event is interested in, see EV_.. above. */
	short ev_events;
	/** timeout value */
	struct timeval ev_timeout;

	/** callback to call: fd, eventbits, userarg */
	void (*ev_callback)(int, short, void *arg);
	/** callback user arg */
	void *ev_arg;
};

/* function prototypes (some are as they appear in event.h) */
/** create event base */
void *event_init(uint32_t* time_secs, struct timeval* time_tv);
/** get version */
const char *event_get_version(void);
/** get polling method, select */
const char *event_get_method(void);
/** run select in a loop */
int event_base_dispatch(struct event_base *);
/** exit that loop */
int event_base_loopexit(struct event_base *, struct timeval *);
/** free event base. Free events yourself */
void event_base_free(struct event_base *);
/** set content of event */
void event_set(struct event *, int, short, void (*)(int, short, void *), void *);
/** add event to a base. You *must* call this for every event. */
int event_base_set(struct event_base *, struct event *);
/** add event to make it active. You may not change it with event_set anymore */
int event_add(struct event *, struct timeval *);
/** remove event. You may change it again */
int event_del(struct event *);

/** add a timer */
#define evtimer_add(ev, tv)             event_add(ev, tv)
/** remove a timer */
#define evtimer_del(ev)                 event_del(ev)

/* uses different implementation. Cannot mix fd/timeouts and signals inside
 * the same struct event. create several event structs for that.  */
/** install signal handler */
int signal_add(struct event *, struct timeval *);
/** set signal event contents */
#define signal_set(ev, x, cb, arg)      \
        event_set(ev, x, EV_SIGNAL|EV_PERSIST, cb, arg)
/** remove signal handler */
int signal_del(struct event *);

#endif /* USE_MINI_EVENT and not USE_WINSOCK */

/** compare events in tree, based on timevalue, ptr for uniqueness */
int mini_ev_cmp(const void* a, const void* b);

#endif /* MINI_EVENT_H */
OpenPOWER on IntegriCloud