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 25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 33 * SOFTWARE, EVEN IF ADVISED OF THE 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 #ifdef HAVE_SYS_SELECT_H 58 /* for fd_set on OpenBSD */ 59 #include <sys/select.h> 60 #endif 61 #include <sys/time.h> 62 63 #ifndef HAVE_EVENT_BASE_FREE 64 #define HAVE_EVENT_BASE_FREE 65 #endif 66 67 /* redefine to use our own namespace so that on platforms where 68 * linkers crosslink library-private symbols with other symbols, it works */ 69 #define event_init minievent_init 70 #define event_get_version minievent_get_version 71 #define event_get_method minievent_get_method 72 #define event_base_dispatch minievent_base_dispatch 73 #define event_base_loopexit minievent_base_loopexit 74 #define event_base_free minievent_base_free 75 #define event_set minievent_set 76 #define event_base_set minievent_base_set 77 #define event_add minievent_add 78 #define event_del minievent_del 79 #define signal_add minisignal_add 80 #define signal_del minisignal_del 81 82 /** event timeout */ 83 #define EV_TIMEOUT 0x01 84 /** event fd readable */ 85 #define EV_READ 0x02 86 /** event fd writable */ 87 #define EV_WRITE 0x04 88 /** event signal */ 89 #define EV_SIGNAL 0x08 90 /** event must persist */ 91 #define EV_PERSIST 0x10 92 93 /* needs our redblack tree */ 94 #include "rbtree.h" 95 96 /** max number of file descriptors to support */ 97 #define MAX_FDS 1024 98 /** max number of signals to support */ 99 #define MAX_SIG 32 100 101 /** event base */ 102 struct event_base 103 { 104 /** sorted by timeout (absolute), ptr */ 105 rbtree_type* times; 106 /** array of 0 - maxfd of ptr to event for it */ 107 struct event** fds; 108 /** max fd in use */ 109 int maxfd; 110 /** capacity - size of the fds array */ 111 int capfd; 112 /* fdset for read write, for fds ready, and added */ 113 fd_set 114 /** fds for reading */ 115 reads, 116 /** fds for writing */ 117 writes, 118 /** fds determined ready for use */ 119 ready, 120 /** ready plus newly added events. */ 121 content; 122 /** array of 0 - maxsig of ptr to event for it */ 123 struct event** signals; 124 /** if we need to exit */ 125 int need_to_exit; 126 /** where to store time in seconds */ 127 time_t* time_secs; 128 /** where to store time in microseconds */ 129 struct timeval* time_tv; 130 }; 131 132 /** 133 * Event structure. Has some of the event elements. 134 */ 135 struct event { 136 /** node in timeout rbtree */ 137 rbnode_type node; 138 /** is event already added */ 139 int added; 140 141 /** event base it belongs to */ 142 struct event_base *ev_base; 143 /** fd to poll or -1 for timeouts. signal number for sigs. */ 144 int ev_fd; 145 /** what events this event is interested in, see EV_.. above. */ 146 short ev_events; 147 /** timeout value */ 148 struct timeval ev_timeout; 149 150 /** callback to call: fd, eventbits, userarg */ 151 void (*ev_callback)(int, short, void *arg); 152 /** callback user arg */ 153 void *ev_arg; 154 }; 155 156 /* function prototypes (some are as they appear in event.h) */ 157 /** create event base */ 158 void *event_init(time_t* time_secs, struct timeval* time_tv); 159 /** get version */ 160 const char *event_get_version(void); 161 /** get polling method, select */ 162 const char *event_get_method(void); 163 /** run select in a loop */ 164 int event_base_dispatch(struct event_base *); 165 /** exit that loop */ 166 int event_base_loopexit(struct event_base *, struct timeval *); 167 /** free event base. Free events yourself */ 168 void event_base_free(struct event_base *); 169 /** set content of event */ 170 void event_set(struct event *, int, short, void (*)(int, short, void *), void *); 171 /** add event to a base. You *must* call this for every event. */ 172 int event_base_set(struct event_base *, struct event *); 173 /** add event to make it active. You may not change it with event_set anymore */ 174 int event_add(struct event *, struct timeval *); 175 /** remove event. You may change it again */ 176 int event_del(struct event *); 177 178 /** add a timer */ 179 #define evtimer_add(ev, tv) event_add(ev, tv) 180 /** remove a timer */ 181 #define evtimer_del(ev) event_del(ev) 182 183 /* uses different implementation. Cannot mix fd/timeouts and signals inside 184 * the same struct event. create several event structs for that. */ 185 /** install signal handler */ 186 int signal_add(struct event *, struct timeval *); 187 /** set signal event contents */ 188 #define signal_set(ev, x, cb, arg) \ 189 event_set(ev, x, EV_SIGNAL|EV_PERSIST, cb, arg) 190 /** remove signal handler */ 191 int signal_del(struct event *); 192 193 #endif /* USE_MINI_EVENT and not USE_WINSOCK */ 194 195 /** compare events in tree, based on timevalue, ptr for uniqueness */ 196 int mini_ev_cmp(const void* a, const void* b); 197 198 #endif /* MINI_EVENT_H */ 199