git.meshlink.io Git - meshlink/blob - src/event.c

   1 /*
   2     event.c -- I/O, timeout and signal event handling
   3     Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License along
  16     with this program; if not, write to the Free Software Foundation, Inc.,
  17     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include "system.h"
  21
  22 #include "dropin.h"
  23 #include "event.h"
  24 #include "net.h"
  25 #include "splay_tree.h"
  26 #include "utils.h"
  27 #include "xalloc.h"
  28
  29 static int io_compare(const io_t *a, const io_t *b) {
  30         return a->fd - b->fd;
  31 }
  32
  33 static int timeout_compare(const timeout_t *a, const timeout_t *b) {
  34         struct timeval diff;
  35         timersub(&a->tv, &b->tv, &diff);
  36         if(diff.tv_sec < 0)
  37                 return -1;
  38         if(diff.tv_sec > 0)
  39                 return 1;
  40         if(diff.tv_usec < 0)
  41                 return -1;
  42         if(diff.tv_usec > 0)
  43                 return 1;
  44         if(a < b)
  45                 return -1;
  46         if(a > b)
  47                 return 1;
  48         return 0;
  49 }
  50
  51 void io_add(event_loop_t *loop, io_t *io, io_cb_t cb, void *data, int fd, int flags) {
  52         if(io->cb)
  53                 return;
  54
  55         io->fd = fd;
  56         io->cb = cb;
  57         io->data = data;
  58         io->node.data = io;
  59
  60         io_set(loop, io, flags);
  61
  62         if(!splay_insert_node(&loop->ios, &io->node))
  63                 abort();
  64 }
  65
  66 void io_set(event_loop_t *loop, io_t *io, int flags) {
  67         io->flags = flags;
  68
  69         if(flags & IO_READ)
  70                 FD_SET(io->fd, &loop->readfds);
  71         else
  72                 FD_CLR(io->fd, &loop->readfds);
  73
  74         if(flags & IO_WRITE)
  75                 FD_SET(io->fd, &loop->writefds);
  76         else
  77                 FD_CLR(io->fd, &loop->writefds);
  78 }
  79
  80 void io_del(event_loop_t *loop, io_t *io) {
  81         if(!io->cb)
  82                 return;
  83
  84         io_set(loop, io, 0);
  85
  86         splay_unlink_node(&loop->ios, &io->node);
  87         io->cb = NULL;
  88 }
  89
  90 void timeout_add(event_loop_t *loop, timeout_t *timeout, timeout_cb_t cb, void *data, struct timeval *tv) {
  91         timeout->cb = cb;
  92         timeout->data = data;
  93         timeout->node.data = timeout;
  94
  95         timeout_set(loop, timeout, tv);
  96 }
  97
  98 void timeout_set(event_loop_t *loop, timeout_t *timeout, struct timeval *tv) {
  99         if(timerisset(&timeout->tv))
 100                 splay_unlink_node(&loop->timeouts, &timeout->node);
 101
 102         if(!loop->now.tv_sec)
 103                 gettimeofday(&loop->now, NULL);
 104
 105         timeradd(&loop->now, tv, &timeout->tv);
 106
 107         if(!splay_insert_node(&loop->timeouts, &timeout->node))
 108                 abort();
 109 }
 110
 111 void timeout_del(event_loop_t *loop, timeout_t *timeout) {
 112         if(!timeout->cb)
 113                 return;
 114
 115         splay_unlink_node(&loop->timeouts, &timeout->node);
 116         timeout->cb = 0;
 117         timeout->tv = (struct timeval){0, 0};
 118 }
 119
 120 static int signal_compare(const signal_t *a, const signal_t *b) {
 121         return (int)a->signum - (int)b->signum;
 122 }
 123
 124 static void signalio_handler(event_loop_t *loop, void *data, int flags) {
 125         unsigned char signum;
 126         if(read(loop->pipefd[0], &signum, 1) != 1)
 127                 return;
 128
 129         signal_t *sig = splay_search(&loop->signals, &((signal_t){.signum = signum}));
 130         if(sig)
 131                 sig->cb(loop, sig->data);
 132 }
 133
 134 static void pipe_init(event_loop_t *loop) {
 135         if(!pipe(loop->pipefd))
 136                 io_add(loop, &loop->signalio, signalio_handler, NULL, loop->pipefd[0], IO_READ);
 137 }
 138
 139 void signal_add(event_loop_t *loop, signal_t *sig, signal_cb_t cb, void *data, uint8_t signum) {
 140         if(sig->cb)
 141                 return;
 142
 143         sig->cb = cb;
 144         sig->data = data;
 145         sig->signum = signum;
 146         sig->node.data = sig;
 147
 148         if(loop->pipefd[0] == -1)
 149                 pipe_init(loop);
 150
 151         if(!splay_insert_node(&loop->signals, &sig->node))
 152                 abort();
 153 }
 154
 155 void signal_del(event_loop_t *loop, signal_t *sig) {
 156         if(!sig->cb)
 157                 return;
 158
 159         splay_unlink_node(&loop->signals, &sig->node);
 160         sig->cb = NULL;
 161 }
 162
 163 bool event_loop_run(event_loop_t *loop) {
 164         loop->running = true;
 165
 166         fd_set readable;
 167         fd_set writable;
 168
 169         while(loop->running) {
 170                 gettimeofday(&loop->now, NULL);
 171                 struct timeval diff, *tv = NULL;
 172
 173                 while(loop->timeouts.head) {
 174                         timeout_t *timeout = loop->timeouts.head->data;
 175                         timersub(&timeout->tv, &loop->now, &diff);
 176
 177                         if(diff.tv_sec < 0) {
 178                                 timeout->cb(loop, timeout->data);
 179                                 if(timercmp(&timeout->tv, &loop->now, <))
 180                                         timeout_del(loop, timeout);
 181                         } else {
 182                                 tv = &diff;
 183                                 break;
 184                         }
 185                 }
 186
 187                 memcpy(&readable, &loop->readfds, sizeof readable);
 188                 memcpy(&writable, &loop->writefds, sizeof writable);
 189
 190                 int fds = 0;
 191
 192                 if(loop->ios.tail) {
 193                         io_t *last = loop->ios.tail->data;
 194                         fds = last->fd + 1;
 195                 }
 196
 197                 int n = select(fds, &readable, &writable, NULL, tv);
 198
 199                 if(n < 0) {
 200                         if(sockwouldblock(errno))
 201                                 continue;
 202                         else
 203                                 return false;
 204                 }
 205
 206                 if(!n)
 207                         continue;
 208
 209                 for splay_each(io_t, io, &loop->ios) {
 210                         if(FD_ISSET(io->fd, &writable))
 211                                 io->cb(loop, io->data, IO_WRITE);
 212                         else if(FD_ISSET(io->fd, &readable))
 213                                 io->cb(loop, io->data, IO_READ);
 214                 }
 215         }
 216
 217         return true;
 218 }
 219
 220 void event_flush_output(event_loop_t *loop) {
 221         for splay_each(io_t, io, &loop->ios)
 222                 if(FD_ISSET(io->fd, &loop->writefds))
 223                         io->cb(loop, io->data, IO_WRITE);
 224 }
 225
 226 void event_loop_stop(event_loop_t *loop) {
 227         loop->running = false;
 228 }
 229
 230 void event_loop_init(event_loop_t *loop) {
 231         loop->ios.compare = (splay_compare_t)io_compare;
 232         loop->timeouts.compare = (splay_compare_t)timeout_compare;
 233         loop->signals.compare = (splay_compare_t)signal_compare;
 234         loop->pipefd[0] = -1;
 235         loop->pipefd[1] = -1;
 236         gettimeofday(&loop->now, NULL);
 237 }
 238
 239 void event_loop_exit(event_loop_t *loop) {
 240         for splay_each(io_t, io, &loop->ios)
 241                 splay_free_node(&loop->ios, node);
 242         for splay_each(timeout_t, timeout, &loop->timeouts)
 243                 splay_free_node(&loop->timeouts, node);
 244         for splay_each(signal_t, signal, &loop->signals)
 245                 splay_free_node(&loop->signals, node);
 246 }