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         loop->deletion = true;
  85
  86         io_set(loop, io, 0);
  87
  88         splay_unlink_node(&loop->ios, &io->node);
  89         io->cb = NULL;
  90 }
  91
  92 void timeout_add(event_loop_t *loop, timeout_t *timeout, timeout_cb_t cb, void *data, struct timeval *tv) {
  93         if(!timeout->cb)
  94                 timeout->tv = (struct timeval){0, 0};
  95
  96         timeout->cb = cb;
  97         timeout->data = data;
  98         timeout->node.data = timeout;
  99
 100         timeout_set(loop, timeout, tv);
 101 }
 102
 103 void timeout_set(event_loop_t *loop, timeout_t *timeout, struct timeval *tv) {
 104         if(timerisset(&timeout->tv))
 105                 splay_unlink_node(&loop->timeouts, &timeout->node);
 106
 107         if(!loop->now.tv_sec)
 108                 gettimeofday(&loop->now, NULL);
 109
 110         timeradd(&loop->now, tv, &timeout->tv);
 111
 112         if(!splay_insert_node(&loop->timeouts, &timeout->node))
 113                 abort();
 114 }
 115
 116 void timeout_del(event_loop_t *loop, timeout_t *timeout) {
 117         if(!timeout->cb)
 118                 return;
 119
 120         loop->deletion = true;
 121
 122         splay_unlink_node(&loop->timeouts, &timeout->node);
 123         timeout->cb = 0;
 124         timeout->tv = (struct timeval){0, 0};
 125 }
 126
 127 static int signal_compare(const signal_t *a, const signal_t *b) {
 128         return (int)a->signum - (int)b->signum;
 129 }
 130
 131 static void signalio_handler(event_loop_t *loop, void *data, int flags) {
 132         unsigned char signum;
 133         if(read(loop->pipefd[0], &signum, 1) != 1)
 134                 return;
 135
 136         signal_t *sig = splay_search(&loop->signals, &((signal_t){.signum = signum}));
 137         if(sig)
 138                 sig->cb(loop, sig->data);
 139 }
 140
 141 static void pipe_init(event_loop_t *loop) {
 142         if(!pipe(loop->pipefd))
 143                 io_add(loop, &loop->signalio, signalio_handler, NULL, loop->pipefd[0], IO_READ);
 144 }
 145
 146 void signal_trigger(event_loop_t *loop, signal_t *sig) {
 147
 148         uint8_t signum = sig->signum;
 149         write(loop->pipefd[1], &signum, 1);
 150         return;
 151
 152 }
 153
 154 void signal_add(event_loop_t *loop, signal_t *sig, signal_cb_t cb, void *data, uint8_t signum) {
 155         if(sig->cb)
 156                 return;
 157
 158         sig->cb = cb;
 159         sig->data = data;
 160         sig->signum = signum;
 161         sig->node.data = sig;
 162
 163         if(loop->pipefd[0] == -1)
 164                 pipe_init(loop);
 165
 166         if(!splay_insert_node(&loop->signals, &sig->node))
 167                 abort();
 168 }
 169
 170 void signal_del(event_loop_t *loop, signal_t *sig) {
 171         if(!sig->cb)
 172                 return;
 173
 174         loop->deletion = true;
 175
 176         splay_unlink_node(&loop->signals, &sig->node);
 177         sig->cb = NULL;
 178 }
 179
 180 bool event_loop_run(event_loop_t *loop) {
 181         loop->running = true;
 182
 183         fd_set readable;
 184         fd_set writable;
 185
 186         while(loop->running) {
 187                 gettimeofday(&loop->now, NULL);
 188                 struct timeval diff, *tv = NULL;
 189
 190                 while(loop->timeouts.head) {
 191                         timeout_t *timeout = loop->timeouts.head->data;
 192                         timersub(&timeout->tv, &loop->now, &diff);
 193
 194                         if(diff.tv_sec < 0) {
 195                                 timeout->cb(loop, timeout->data);
 196                                 if(timercmp(&timeout->tv, &loop->now, <))
 197                                         timeout_del(loop, timeout);
 198                         } else {
 199                                 tv = &diff;
 200                                 break;
 201                         }
 202                 }
 203
 204                 memcpy(&readable, &loop->readfds, sizeof readable);
 205                 memcpy(&writable, &loop->writefds, sizeof writable);
 206
 207                 int fds = 0;
 208
 209                 if(loop->ios.tail) {
 210                         io_t *last = loop->ios.tail->data;
 211                         fds = last->fd + 1;
 212                 }
 213
 214                 int n = select(fds, &readable, &writable, NULL, tv);
 215
 216                 if(n < 0) {
 217                         if(sockwouldblock(errno))
 218                                 continue;
 219                         else
 220                                 return false;
 221                 }
 222
 223                 if(!n)
 224                         continue;
 225
 226                 // Normally, splay_each allows the current node to be deleted. However,
 227                 // it can be that one io callback triggers the deletion of another io,
 228                 // so we have to detect this and break the loop.
 229
 230                 loop->deletion = false;
 231
 232                 for splay_each(io_t, io, &loop->ios) {
 233                         if(FD_ISSET(io->fd, &writable) && io->cb)
 234                                 io->cb(loop, io->data, IO_WRITE);
 235                         if(loop->deletion)
 236                                 break;
 237                         if(FD_ISSET(io->fd, &readable) && io->cb)
 238                                 io->cb(loop, io->data, IO_READ);
 239                         if(loop->deletion)
 240                                 break;
 241                 }
 242         }
 243
 244         return true;
 245 }
 246
 247 void event_flush_output(event_loop_t *loop) {
 248         for splay_each(io_t, io, &loop->ios)
 249                 if(FD_ISSET(io->fd, &loop->writefds))
 250                         io->cb(loop, io->data, IO_WRITE);
 251 }
 252
 253 void event_loop_stop(event_loop_t *loop) {
 254         loop->running = false;
 255 }
 256
 257 void event_loop_init(event_loop_t *loop) {
 258         loop->ios.compare = (splay_compare_t)io_compare;
 259         loop->timeouts.compare = (splay_compare_t)timeout_compare;
 260         loop->signals.compare = (splay_compare_t)signal_compare;
 261         loop->pipefd[0] = -1;
 262         loop->pipefd[1] = -1;
 263         gettimeofday(&loop->now, NULL);
 264 }
 265
 266 void event_loop_exit(event_loop_t *loop) {
 267         for splay_each(io_t, io, &loop->ios)
 268                 splay_unlink_node(&loop->ios, node);
 269         for splay_each(timeout_t, timeout, &loop->timeouts)
 270                 splay_unlink_node(&loop->timeouts, node);
 271         for splay_each(signal_t, signal, &loop->signals)
 272                 splay_unlink_node(&loop->signals, node);
 273 }