1 /* 2 * mini-event.h - micro implementation of libevent api, using select() only. 3 * 4 * Copyright (c) 2007, NLnet Labs. All rights reserved. 5 * 6 * This software is open source. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * Redistributions of source code must retain the above copyright notice, 13 * this list of conditions and the following disclaimer. 14 * 15 * Redistributions in binary form must reproduce the above copyright notice, 16 * this list of conditions and the following disclaimer in the documentation 17 * and/or other materials provided with the distribution. 18 * 19 * Neither the name of the NLNET LABS nor the names of its contributors may 20 * be used to endorse or promote products derived from this software without 21 * specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE 27 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 28 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 * POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 /** 37 * \file 38 * This file implements part of the event(3) libevent api. 39 * The back end is only select. Max number of fds is limited. 40 * Max number of signals is limited, one handler per signal only. 41 * And one handler per fd. 42 * 43 * Although limited to select() and a max (1024) open fds, it 44 * is efficient: 45 * o dispatch call caches fd_sets to use. 46 * o handler calling takes time ~ to the number of fds. 47 * o timeouts are stored in a redblack tree, sorted, so take log(n). 48 * Timeouts are only accurate to the second (no subsecond accuracy). 49 * To avoid cpu hogging, fractional timeouts are rounded up to a whole second. 50 */ 51 52 #ifndef MINI_EVENT_H 53 #define MINI_EVENT_H 54 55 #if defined(USE_MINI_EVENT) && !defined(USE_WINSOCK) 56 57 #ifndef HAVE_EVENT_BASE_FREE 58 #define HAVE_EVENT_BASE_FREE 59 #endif 60 61 /** event timeout */ 62 #define EV_TIMEOUT 0x01 63 /** event fd readable */ 64 #define EV_READ 0x02 65 /** event fd writable */ 66 #define EV_WRITE 0x04 67 /** event signal */ 68 #define EV_SIGNAL 0x08 69 /** event must persist */ 70 #define EV_PERSIST 0x10 71 72 /* needs our redblack tree */ 73 #include "rbtree.h" 74 75 /** max number of file descriptors to support */ 76 #define MAX_FDS 1024 77 /** max number of signals to support */ 78 #define MAX_SIG 32 79 80 /** event base */ 81 struct event_base 82 { 83 /** sorted by timeout (absolute), ptr */ 84 rbtree_t* times; 85 /** array of 0 - maxfd of ptr to event for it */ 86 struct event** fds; 87 /** max fd in use */ 88 int maxfd; 89 /** capacity - size of the fds array */ 90 int capfd; 91 /* fdset for read write, for fds ready, and added */ 92 fd_set 93 /** fds for reading */ 94 reads, 95 /** fds for writing */ 96 writes, 97 /** fds determined ready for use */ 98 ready, 99 /** ready plus newly added events. */ 100 content; 101 /** array of 0 - maxsig of ptr to event for it */ 102 struct event** signals; 103 /** if we need to exit */ 104 int need_to_exit; 105 /** where to store time in seconds */ 106 uint32_t* time_secs; 107 /** where to store time in microseconds */ 108 struct timeval* time_tv; 109 }; 110 111 /** 112 * Event structure. Has some of the event elements. 113 */ 114 struct event { 115 /** node in timeout rbtree */ 116 rbnode_t node; 117 /** is event already added */ 118 int added; 119 120 /** event base it belongs to */ 121 struct event_base *ev_base; 122 /** fd to poll or -1 for timeouts. signal number for sigs. */ 123 int ev_fd; 124 /** what events this event is interested in, see EV_.. above. */ 125 short ev_events; 126 /** timeout value */ 127 struct timeval ev_timeout; 128 129 /** callback to call: fd, eventbits, userarg */ 130 void (*ev_callback)(int, short, void *arg); 131 /** callback user arg */ 132 void *ev_arg; 133 }; 134 135 /* function prototypes (some are as they appear in event.h) */ 136 /** create event base */ 137 void *event_init(uint32_t* time_secs, struct timeval* time_tv); 138 /** get version */ 139 const char *event_get_version(void); 140 /** get polling method, select */ 141 const char *event_get_method(void); 142 /** run select in a loop */ 143 int event_base_dispatch(struct event_base *); 144 /** exit that loop */ 145 int event_base_loopexit(struct event_base *, struct timeval *); 146 /** free event base. Free events yourself */ 147 void event_base_free(struct event_base *); 148 /** set content of event */ 149 void event_set(struct event *, int, short, void (*)(int, short, void *), void *); 150 /** add event to a base. You *must* call this for every event. */ 151 int event_base_set(struct event_base *, struct event *); 152 /** add event to make it active. You may not change it with event_set anymore */ 153 int event_add(struct event *, struct timeval *); 154 /** remove event. You may change it again */ 155 int event_del(struct event *); 156 157 /** add a timer */ 158 #define evtimer_add(ev, tv) event_add(ev, tv) 159 /** remove a timer */ 160 #define evtimer_del(ev) event_del(ev) 161 162 /* uses different implementation. Cannot mix fd/timeouts and signals inside 163 * the same struct event. create several event structs for that. */ 164 /** install signal handler */ 165 int signal_add(struct event *, struct timeval *); 166 /** set signal event contents */ 167 #define signal_set(ev, x, cb, arg) \ 168 event_set(ev, x, EV_SIGNAL|EV_PERSIST, cb, arg) 169 /** remove signal handler */ 170 int signal_del(struct event *); 171 172 #endif /* USE_MINI_EVENT and not USE_WINSOCK */ 173 174 /** compare events in tree, based on timevalue, ptr for uniqueness */ 175 int mini_ev_cmp(const void* a, const void* b); 176 177 #endif /* MINI_EVENT_H */ 178