contrib/pf/libevent/poll.c

   1 /*      $OpenBSD: poll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */
   2
   3 /*
   4  * Copyright 2000-2003 Niels Provos <provos@citi.umich.edu>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. The name of the author may not be used to endorse or promote products
  16  *    derived from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29 #ifdef HAVE_CONFIG_H
  30 #include "config.h"
  31 #endif
  32
  33 #include <sys/types.h>
  34 #ifdef HAVE_SYS_TIME_H
  35 #include <sys/time.h>
  36 #else
  37 #include <sys/_time.h>
  38 #endif
  39 #include <sys/queue.h>
  40 #include <sys/tree.h>
  41 #include <poll.h>
  42 #include <signal.h>
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include <unistd.h>
  47 #include <errno.h>
  48 #ifdef CHECK_INVARIANTS
  49 #include <assert.h>
  50 #endif
  51
  52 #include "event.h"
  53 #include "event-internal.h"
  54 #include "evsignal.h"
  55 #include "log.h"
  56
  57 extern volatile sig_atomic_t evsignal_caught;
  58
  59 struct pollop {
  60         int event_count;                /* Highest number alloc */
  61         int nfds;                       /* Size of event_* */
  62         int fd_count;                   /* Size of idxplus1_by_fd */
  63         struct pollfd *event_set;
  64         struct event **event_r_back;
  65         struct event **event_w_back;
  66         int *idxplus1_by_fd; /* Index into event_set by fd; we add 1 so
  67                               * that 0 (which is easy to memset) can mean
  68                               * "no entry." */
  69 };
  70
  71 void *poll_init (void);
  72 int poll_add            (void *, struct event *);
  73 int poll_del            (void *, struct event *);
  74 int poll_recalc         (struct event_base *, void *, int);
  75 int poll_dispatch       (struct event_base *, void *, struct timeval *);
  76 void poll_dealloc       (void *);
  77
  78 const struct eventop pollops = {
  79         "poll",
  80         poll_init,
  81         poll_add,
  82         poll_del,
  83         poll_recalc,
  84         poll_dispatch,
  85         poll_dealloc
  86 };
  87
  88 void *
  89 poll_init(void)
  90 {
  91         struct pollop *pollop;
  92
  93         /* Disable poll when this environment variable is set */
  94         if (getenv("EVENT_NOPOLL"))
  95                 return (NULL);
  96
  97         if (!(pollop = calloc(1, sizeof(struct pollop))))
  98                 return (NULL);
  99
 100         evsignal_init();
 101
 102         return (pollop);
 103 }
 104
 105 /*
 106  * Called with the highest fd that we know about.  If it is 0, completely
 107  * recalculate everything.
 108  */
 109
 110 int
 111 poll_recalc(struct event_base *base, void *arg, int max)
 112 {
 113         return (0);
 114 }
 115
 116 #ifdef CHECK_INVARIANTS
 117 static void
 118 poll_check_ok(struct pollop *pop)
 119 {
 120         int i, idx;
 121         struct event *ev;
 122
 123         for (i = 0; i < pop->fd_count; ++i) {
 124                 idx = pop->idxplus1_by_fd[i]-1;
 125                 if (idx < 0)
 126                         continue;
 127                 assert(pop->event_set[idx].fd == i);
 128                 if (pop->event_set[idx].events & POLLIN) {
 129                         ev = pop->event_r_back[idx];
 130                         assert(ev);
 131                         assert(ev->ev_events & EV_READ);
 132                         assert(ev->ev_fd == i);
 133                 }
 134                 if (pop->event_set[idx].events & POLLOUT) {
 135                         ev = pop->event_w_back[idx];
 136                         assert(ev);
 137                         assert(ev->ev_events & EV_WRITE);
 138                         assert(ev->ev_fd == i);
 139                 }
 140         }
 141         for (i = 0; i < pop->nfds; ++i) {
 142                 struct pollfd *pfd = &pop->event_set[i];
 143                 assert(pop->idxplus1_by_fd[pfd->fd] == i+1);
 144         }
 145 }
 146 #else
 147 #define poll_check_ok(pop)
 148 #endif
 149
 150 int
 151 poll_dispatch(struct event_base *base, void *arg, struct timeval *tv)
 152 {
 153         int res, i, sec, nfds;
 154         struct pollop *pop = arg;
 155
 156         poll_check_ok(pop);
 157         sec = tv->tv_sec * 1000 + (tv->tv_usec + 999) / 1000;
 158         nfds = pop->nfds;
 159         res = poll(pop->event_set, nfds, sec);
 160
 161         if (res == -1) {
 162                 if (errno != EINTR) {
 163                         event_warn("poll");
 164                         return (-1);
 165                 }
 166
 167                 evsignal_process();
 168                 return (0);
 169         } else if (evsignal_caught)
 170                 evsignal_process();
 171
 172         event_debug(("%s: poll reports %d", __func__, res));
 173
 174         if (res == 0)
 175                 return (0);
 176
 177         for (i = 0; i < nfds; i++) {
 178                 int what = pop->event_set[i].revents;
 179                 struct event *r_ev = NULL, *w_ev = NULL;
 180                 if (!what)
 181                         continue;
 182
 183                 res = 0;
 184
 185                 /* If the file gets closed notify */
 186                 if (what & (POLLHUP|POLLERR))
 187                         what |= POLLIN|POLLOUT;
 188                 if (what & POLLIN) {
 189                         res |= EV_READ;
 190                         r_ev = pop->event_r_back[i];
 191                 }
 192                 if (what & POLLOUT) {
 193                         res |= EV_WRITE;
 194                         w_ev = pop->event_w_back[i];
 195                 }
 196                 if (res == 0)
 197                         continue;
 198
 199                 if (r_ev && (res & r_ev->ev_events)) {
 200                         if (!(r_ev->ev_events & EV_PERSIST))
 201                                 event_del(r_ev);
 202                         event_active(r_ev, res & r_ev->ev_events, 1);
 203                 }
 204                 if (w_ev && w_ev != r_ev && (res & w_ev->ev_events)) {
 205                         if (!(w_ev->ev_events & EV_PERSIST))
 206                                 event_del(w_ev);
 207                         event_active(w_ev, res & w_ev->ev_events, 1);
 208                 }
 209         }
 210
 211         return (0);
 212 }
 213
 214 int
 215 poll_add(void *arg, struct event *ev)
 216 {
 217         struct pollop *pop = arg;
 218         struct pollfd *pfd = NULL;
 219         int i;
 220
 221         if (ev->ev_events & EV_SIGNAL)
 222                 return (evsignal_add(ev));
 223         if (!(ev->ev_events & (EV_READ|EV_WRITE)))
 224                 return (0);
 225
 226         poll_check_ok(pop);
 227         if (pop->nfds + 1 >= pop->event_count) {
 228                 struct pollfd *tmp_event_set;
 229                 struct event **tmp_event_r_back;
 230                 struct event **tmp_event_w_back;
 231                 int tmp_event_count;
 232
 233                 if (pop->event_count < 32)
 234                         tmp_event_count = 32;
 235                 else
 236                         tmp_event_count = pop->event_count * 2;
 237
 238                 /* We need more file descriptors */
 239                 tmp_event_set = realloc(pop->event_set,
 240                                  tmp_event_count * sizeof(struct pollfd));
 241                 if (tmp_event_set == NULL) {
 242                         event_warn("realloc");
 243                         return (-1);
 244                 }
 245                 pop->event_set = tmp_event_set;
 246
 247                 tmp_event_r_back = realloc(pop->event_r_back,
 248                             tmp_event_count * sizeof(struct event *));
 249                 if (tmp_event_r_back == NULL) {
 250                         /* event_set overallocated; that's okay. */
 251                         event_warn("realloc");
 252                         return (-1);
 253                 }
 254                 pop->event_r_back = tmp_event_r_back;
 255
 256                 tmp_event_w_back = realloc(pop->event_w_back,
 257                             tmp_event_count * sizeof(struct event *));
 258                 if (tmp_event_w_back == NULL) {
 259                         /* event_set and event_r_back overallocated; that's
 260                          * okay. */
 261                         event_warn("realloc");
 262                         return (-1);
 263                 }
 264                 pop->event_w_back = tmp_event_w_back;
 265
 266                 pop->event_count = tmp_event_count;
 267         }
 268         if (ev->ev_fd >= pop->fd_count) {
 269                 int *tmp_idxplus1_by_fd;
 270                 int new_count;
 271                 if (pop->fd_count < 32)
 272                         new_count = 32;
 273                 else
 274                         new_count = pop->fd_count * 2;
 275                 while (new_count <= ev->ev_fd)
 276                         new_count *= 2;
 277                 tmp_idxplus1_by_fd =
 278                         realloc(pop->idxplus1_by_fd, new_count * sizeof(int));
 279                 if (tmp_idxplus1_by_fd == NULL) {
 280                         event_warn("realloc");
 281                         return (-1);
 282                 }
 283                 pop->idxplus1_by_fd = tmp_idxplus1_by_fd;
 284                 memset(pop->idxplus1_by_fd + pop->fd_count,
 285                        0, sizeof(int)*(new_count - pop->fd_count));
 286                 pop->fd_count = new_count;
 287         }
 288
 289         i = pop->idxplus1_by_fd[ev->ev_fd] - 1;
 290         if (i >= 0) {
 291                 pfd = &pop->event_set[i];
 292         } else {
 293                 i = pop->nfds++;
 294                 pfd = &pop->event_set[i];
 295                 pfd->events = 0;
 296                 pfd->fd = ev->ev_fd;
 297                 pop->event_w_back[i] = pop->event_r_back[i] = NULL;
 298                 pop->idxplus1_by_fd[ev->ev_fd] = i + 1;
 299         }
 300
 301         pfd->revents = 0;
 302         if (ev->ev_events & EV_WRITE) {
 303                 pfd->events |= POLLOUT;
 304                 pop->event_w_back[i] = ev;
 305         }
 306         if (ev->ev_events & EV_READ) {
 307                 pfd->events |= POLLIN;
 308                 pop->event_r_back[i] = ev;
 309         }
 310         poll_check_ok(pop);
 311
 312         return (0);
 313 }
 314
 315 /*
 316  * Nothing to be done here.
 317  */
 318
 319 int
 320 poll_del(void *arg, struct event *ev)
 321 {
 322         struct pollop *pop = arg;
 323         struct pollfd *pfd = NULL;
 324         int i;
 325
 326         if (ev->ev_events & EV_SIGNAL)
 327                 return (evsignal_del(ev));
 328
 329         if (!(ev->ev_events & (EV_READ|EV_WRITE)))
 330                 return (0);
 331
 332         poll_check_ok(pop);
 333         i = pop->idxplus1_by_fd[ev->ev_fd] - 1;
 334         if (i < 0)
 335                 return (-1);
 336
 337         /* Do we still want to read or write? */
 338         pfd = &pop->event_set[i];
 339         if (ev->ev_events & EV_READ) {
 340                 pfd->events &= ~POLLIN;
 341                 pop->event_r_back[i] = NULL;
 342         }
 343         if (ev->ev_events & EV_WRITE) {
 344                 pfd->events &= ~POLLOUT;
 345                 pop->event_w_back[i] = NULL;
 346         }
 347         poll_check_ok(pop);
 348         if (pfd->events)
 349                 /* Another event cares about that fd. */
 350                 return (0);
 351
 352         /* Okay, so we aren't interested in that fd anymore. */
 353         pop->idxplus1_by_fd[ev->ev_fd] = 0;
 354
 355         --pop->nfds;
 356         if (i != pop->nfds) {
 357                 /*
 358                  * Shift the last pollfd down into the now-unoccupied
 359                  * position.
 360                  */
 361                 memcpy(&pop->event_set[i], &pop->event_set[pop->nfds],
 362                        sizeof(struct pollfd));
 363                 pop->event_r_back[i] = pop->event_r_back[pop->nfds];
 364                 pop->event_w_back[i] = pop->event_w_back[pop->nfds];
 365                 pop->idxplus1_by_fd[pop->event_set[i].fd] = i + 1;
 366         }
 367
 368         poll_check_ok(pop);
 369         return (0);
 370 }
 371
 372 void
 373 poll_dealloc(void *arg)
 374 {
 375         struct pollop *pop = arg;
 376
 377         if (pop->event_set)
 378                 free(pop->event_set);
 379         if (pop->event_r_back)
 380                 free(pop->event_r_back);
 381         if (pop->event_w_back)
 382                 free(pop->event_w_back);
 383         if (pop->idxplus1_by_fd)
 384                 free(pop->idxplus1_by_fd);
 385
 386         memset(pop, 0, sizeof(struct pollop));
 387         free(pop);
 388 }