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

   1 /*
   2     event.c -- I/O, timeout and signal event handling
   3     Copyright (C) 2014-2017 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
  37         if(diff.tv_sec < 0) {
  38                 return -1;
  39         }
  40
  41         if(diff.tv_sec > 0) {
  42                 return 1;
  43         }
  44
  45         if(diff.tv_usec < 0) {
  46                 return -1;
  47         }
  48
  49         if(diff.tv_usec > 0) {
  50                 return 1;
  51         }
  52
  53         if(a < b) {
  54                 return -1;
  55         }
  56
  57         if(a > b) {
  58                 return 1;
  59         }
  60
  61         return 0;
  62 }
  63
  64 void io_add(event_loop_t *loop, io_t *io, io_cb_t cb, void *data, int fd, int flags) {
  65         if(io->cb) {
  66                 return;
  67         }
  68
  69         io->fd = fd;
  70         io->cb = cb;
  71         io->data = data;
  72         io->node.data = io;
  73
  74         io_set(loop, io, flags);
  75
  76         if(!splay_insert_node(&loop->ios, &io->node)) {
  77                 abort();
  78         }
  79 }
  80
  81 void io_set(event_loop_t *loop, io_t *io, int flags) {
  82         io->flags = flags;
  83
  84         if(flags & IO_READ) {
  85                 FD_SET(io->fd, &loop->readfds);
  86         } else {
  87                 FD_CLR(io->fd, &loop->readfds);
  88         }
  89
  90         if(flags & IO_WRITE) {
  91                 FD_SET(io->fd, &loop->writefds);
  92         } else {
  93                 FD_CLR(io->fd, &loop->writefds);
  94         }
  95 }
  96
  97 void io_del(event_loop_t *loop, io_t *io) {
  98         if(!io->cb) {
  99                 return;
 100         }
 101
 102         loop->deletion = true;
 103
 104         io_set(loop, io, 0);
 105
 106         splay_unlink_node(&loop->ios, &io->node);
 107         io->cb = NULL;
 108 }
 109
 110 void timeout_add(event_loop_t *loop, timeout_t *timeout, timeout_cb_t cb, void *data, struct timeval *tv) {
 111         if(!timeout->cb)
 112                 timeout->tv = (struct timeval) {
 113                 0, 0
 114         };
 115
 116         timeout->cb = cb;
 117
 118         timeout->data = data;
 119
 120         timeout->node.data = timeout;
 121
 122         timeout_set(loop, timeout, tv);
 123 }
 124
 125 void timeout_set(event_loop_t *loop, timeout_t *timeout, struct timeval *tv) {
 126         if(timerisset(&timeout->tv)) {
 127                 splay_unlink_node(&loop->timeouts, &timeout->node);
 128         }
 129
 130         if(!loop->now.tv_sec) {
 131                 gettimeofday(&loop->now, NULL);
 132         }
 133
 134         timeradd(&loop->now, tv, &timeout->tv);
 135
 136         if(!splay_insert_node(&loop->timeouts, &timeout->node)) {
 137                 abort();
 138         }
 139 }
 140
 141 void timeout_del(event_loop_t *loop, timeout_t *timeout) {
 142         if(!timeout->cb) {
 143                 return;
 144         }
 145
 146         loop->deletion = true;
 147
 148         splay_unlink_node(&loop->timeouts, &timeout->node);
 149         timeout->cb = 0;
 150         timeout->tv = (struct timeval) {
 151                 0, 0
 152         };
 153 }
 154
 155 static int signal_compare(const signal_t *a, const signal_t *b) {
 156         return (int)a->signum - (int)b->signum;
 157 }
 158
 159 static void signalio_handler(event_loop_t *loop, void *data, int flags) {
 160         (void)data;
 161         (void)flags;
 162         unsigned char signum;
 163
 164         if(read(loop->pipefd[0], &signum, 1) != 1) {
 165                 return;
 166         }
 167
 168         signal_t *sig = splay_search(&loop->signals, &((signal_t) {
 169                 .signum = signum
 170         }));
 171
 172         if(sig) {
 173                 sig->cb(loop, sig->data);
 174         }
 175 }
 176
 177 static void pipe_init(event_loop_t *loop) {
 178         if(!pipe(loop->pipefd)) {
 179                 io_add(loop, &loop->signalio, signalio_handler, NULL, loop->pipefd[0], IO_READ);
 180         }
 181 }
 182
 183 void signal_trigger(event_loop_t *loop, signal_t *sig) {
 184
 185         uint8_t signum = sig->signum;
 186         write(loop->pipefd[1], &signum, 1);
 187         return;
 188
 189 }
 190
 191 void signal_add(event_loop_t *loop, signal_t *sig, signal_cb_t cb, void *data, uint8_t signum) {
 192         if(sig->cb) {
 193                 return;
 194         }
 195
 196         sig->cb = cb;
 197         sig->data = data;
 198         sig->signum = signum;
 199         sig->node.data = sig;
 200
 201         if(loop->pipefd[0] == -1) {
 202                 pipe_init(loop);
 203         }
 204
 205         if(!splay_insert_node(&loop->signals, &sig->node)) {
 206                 abort();
 207         }
 208 }
 209
 210 void signal_del(event_loop_t *loop, signal_t *sig) {
 211         if(!sig->cb) {
 212                 return;
 213         }
 214
 215         loop->deletion = true;
 216
 217         splay_unlink_node(&loop->signals, &sig->node);
 218         sig->cb = NULL;
 219 }
 220
 221 void idle_set(event_loop_t *loop, idle_cb_t cb, void *data) {
 222         loop->idle_cb = cb;
 223         loop->idle_data = data;
 224 }
 225
 226 bool event_loop_run(event_loop_t *loop, pthread_mutex_t *mutex) {
 227         fd_set readable;
 228         fd_set writable;
 229
 230         while(loop->running) {
 231                 gettimeofday(&loop->now, NULL);
 232                 struct timeval diff, it, *tv = NULL;
 233
 234                 while(loop->timeouts.head) {
 235                         timeout_t *timeout = loop->timeouts.head->data;
 236                         timersub(&timeout->tv, &loop->now, &diff);
 237
 238                         if(diff.tv_sec < 0) {
 239                                 timeout->cb(loop, timeout->data);
 240
 241                                 if(timercmp(&timeout->tv, &loop->now, <)) {
 242                                         timeout_del(loop, timeout);
 243                                 }
 244                         } else {
 245                                 tv = &diff;
 246                                 break;
 247                         }
 248                 }
 249
 250                 if(loop->idle_cb) {
 251                         it = loop->idle_cb(loop, loop->idle_data);
 252
 253                         if(it.tv_sec >= 0 && (!tv || timercmp(&it, tv, <))) {
 254                                 tv = &it;
 255                         }
 256                 }
 257
 258                 memcpy(&readable, &loop->readfds, sizeof(readable));
 259                 memcpy(&writable, &loop->writefds, sizeof(writable));
 260
 261                 int fds = 0;
 262
 263                 if(loop->ios.tail) {
 264                         io_t *last = loop->ios.tail->data;
 265                         fds = last->fd + 1;
 266                 }
 267
 268                 // release mesh mutex during select
 269                 if(mutex) {
 270                         pthread_mutex_unlock(mutex);
 271                 }
 272
 273                 int n = select(fds, &readable, &writable, NULL, tv);
 274
 275                 if(mutex) {
 276                         pthread_mutex_lock(mutex);
 277                 }
 278
 279                 if(n < 0) {
 280                         if(sockwouldblock(errno)) {
 281                                 continue;
 282                         } else {
 283                                 return false;
 284                         }
 285                 }
 286
 287                 if(!n) {
 288                         continue;
 289                 }
 290
 291                 // Normally, splay_each allows the current node to be deleted. However,
 292                 // it can be that one io callback triggers the deletion of another io,
 293                 // so we have to detect this and break the loop.
 294
 295                 loop->deletion = false;
 296
 297                 for splay_each(io_t, io, &loop->ios) {
 298                         if(FD_ISSET(io->fd, &writable) && io->cb) {
 299                                 io->cb(loop, io->data, IO_WRITE);
 300                         }
 301
 302                         if(loop->deletion) {
 303                                 break;
 304                         }
 305
 306                         if(FD_ISSET(io->fd, &readable) && io->cb) {
 307                                 io->cb(loop, io->data, IO_READ);
 308                         }
 309
 310                         if(loop->deletion) {
 311                                 break;
 312                         }
 313                 }
 314         }
 315
 316         return true;
 317 }
 318
 319 void event_flush_output(event_loop_t *loop) {
 320         for splay_each(io_t, io, &loop->ios)
 321                 if(FD_ISSET(io->fd, &loop->writefds)) {
 322                         io->cb(loop, io->data, IO_WRITE);
 323                 }
 324 }
 325
 326 void event_loop_start(event_loop_t *loop) {
 327         loop->running = true;
 328 }
 329
 330 void event_loop_stop(event_loop_t *loop) {
 331         loop->running = false;
 332 }
 333
 334 void event_loop_init(event_loop_t *loop) {
 335         loop->ios.compare = (splay_compare_t)io_compare;
 336         loop->timeouts.compare = (splay_compare_t)timeout_compare;
 337         loop->signals.compare = (splay_compare_t)signal_compare;
 338         loop->pipefd[0] = -1;
 339         loop->pipefd[1] = -1;
 340         gettimeofday(&loop->now, NULL);
 341 }
 342
 343 void event_loop_exit(event_loop_t *loop) {
 344         for splay_each(io_t, io, &loop->ios) {
 345                 splay_unlink_node(&loop->ios, node);
 346         }
 347
 348         for splay_each(timeout_t, timeout, &loop->timeouts) {
 349                 splay_unlink_node(&loop->timeouts, node);
 350         }
 351
 352         for splay_each(signal_t, signal, &loop->signals) {
 353                 splay_unlink_node(&loop->signals, node);
 354         }
 355 }