Annotation of embedaddon/libevent/select.c, revision 1.1
1.1 ! misho 1: /* $OpenBSD: select.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */
! 2:
! 3: /*
! 4: * Copyright 2000-2002 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/_libevent_time.h>
! 38: #endif
! 39: #ifdef HAVE_SYS_SELECT_H
! 40: #include <sys/select.h>
! 41: #endif
! 42: #include <sys/queue.h>
! 43: #include <signal.h>
! 44: #include <stdio.h>
! 45: #include <stdlib.h>
! 46: #include <string.h>
! 47: #include <unistd.h>
! 48: #include <errno.h>
! 49: #ifdef CHECK_INVARIANTS
! 50: #include <assert.h>
! 51: #endif
! 52:
! 53: #include "event.h"
! 54: #include "evutil.h"
! 55: #include "event-internal.h"
! 56: #include "evsignal.h"
! 57: #include "log.h"
! 58:
! 59: #ifndef howmany
! 60: #define howmany(x, y) (((x)+((y)-1))/(y))
! 61: #endif
! 62:
! 63: #ifndef _EVENT_HAVE_FD_MASK
! 64: /* This type is mandatory, but Android doesn't define it. */
! 65: #undef NFDBITS
! 66: #define NFDBITS (sizeof(long)*8)
! 67: typedef unsigned long fd_mask;
! 68: #endif
! 69:
! 70: struct selectop {
! 71: int event_fds; /* Highest fd in fd set */
! 72: int event_fdsz;
! 73: fd_set *event_readset_in;
! 74: fd_set *event_writeset_in;
! 75: fd_set *event_readset_out;
! 76: fd_set *event_writeset_out;
! 77: struct event **event_r_by_fd;
! 78: struct event **event_w_by_fd;
! 79: };
! 80:
! 81: static void *select_init (struct event_base *);
! 82: static int select_add (void *, struct event *);
! 83: static int select_del (void *, struct event *);
! 84: static int select_dispatch (struct event_base *, void *, struct timeval *);
! 85: static void select_dealloc (struct event_base *, void *);
! 86:
! 87: const struct eventop selectops = {
! 88: "select",
! 89: select_init,
! 90: select_add,
! 91: select_del,
! 92: select_dispatch,
! 93: select_dealloc,
! 94: 0
! 95: };
! 96:
! 97: static int select_resize(struct selectop *sop, int fdsz);
! 98:
! 99: static void *
! 100: select_init(struct event_base *base)
! 101: {
! 102: struct selectop *sop;
! 103:
! 104: /* Disable select when this environment variable is set */
! 105: if (evutil_getenv("EVENT_NOSELECT"))
! 106: return (NULL);
! 107:
! 108: if (!(sop = calloc(1, sizeof(struct selectop))))
! 109: return (NULL);
! 110:
! 111: select_resize(sop, howmany(32 + 1, NFDBITS)*sizeof(fd_mask));
! 112:
! 113: evsignal_init(base);
! 114:
! 115: return (sop);
! 116: }
! 117:
! 118: #ifdef CHECK_INVARIANTS
! 119: static void
! 120: check_selectop(struct selectop *sop)
! 121: {
! 122: int i;
! 123: for (i = 0; i <= sop->event_fds; ++i) {
! 124: if (FD_ISSET(i, sop->event_readset_in)) {
! 125: assert(sop->event_r_by_fd[i]);
! 126: assert(sop->event_r_by_fd[i]->ev_events & EV_READ);
! 127: assert(sop->event_r_by_fd[i]->ev_fd == i);
! 128: } else {
! 129: assert(! sop->event_r_by_fd[i]);
! 130: }
! 131: if (FD_ISSET(i, sop->event_writeset_in)) {
! 132: assert(sop->event_w_by_fd[i]);
! 133: assert(sop->event_w_by_fd[i]->ev_events & EV_WRITE);
! 134: assert(sop->event_w_by_fd[i]->ev_fd == i);
! 135: } else {
! 136: assert(! sop->event_w_by_fd[i]);
! 137: }
! 138: }
! 139:
! 140: }
! 141: #else
! 142: #define check_selectop(sop) do { (void) sop; } while (0)
! 143: #endif
! 144:
! 145: static int
! 146: select_dispatch(struct event_base *base, void *arg, struct timeval *tv)
! 147: {
! 148: int res, i, j;
! 149: struct selectop *sop = arg;
! 150:
! 151: check_selectop(sop);
! 152:
! 153: memcpy(sop->event_readset_out, sop->event_readset_in,
! 154: sop->event_fdsz);
! 155: memcpy(sop->event_writeset_out, sop->event_writeset_in,
! 156: sop->event_fdsz);
! 157:
! 158: res = select(sop->event_fds + 1, sop->event_readset_out,
! 159: sop->event_writeset_out, NULL, tv);
! 160:
! 161: check_selectop(sop);
! 162:
! 163: if (res == -1) {
! 164: if (errno != EINTR) {
! 165: event_warn("select");
! 166: return (-1);
! 167: }
! 168:
! 169: evsignal_process(base);
! 170: return (0);
! 171: } else if (base->sig.evsignal_caught) {
! 172: evsignal_process(base);
! 173: }
! 174:
! 175: event_debug(("%s: select reports %d", __func__, res));
! 176:
! 177: check_selectop(sop);
! 178: i = random() % (sop->event_fds+1);
! 179: for (j = 0; j <= sop->event_fds; ++j) {
! 180: struct event *r_ev = NULL, *w_ev = NULL;
! 181: if (++i >= sop->event_fds+1)
! 182: i = 0;
! 183:
! 184: res = 0;
! 185: if (FD_ISSET(i, sop->event_readset_out)) {
! 186: r_ev = sop->event_r_by_fd[i];
! 187: res |= EV_READ;
! 188: }
! 189: if (FD_ISSET(i, sop->event_writeset_out)) {
! 190: w_ev = sop->event_w_by_fd[i];
! 191: res |= EV_WRITE;
! 192: }
! 193: if (r_ev && (res & r_ev->ev_events)) {
! 194: event_active(r_ev, res & r_ev->ev_events, 1);
! 195: }
! 196: if (w_ev && w_ev != r_ev && (res & w_ev->ev_events)) {
! 197: event_active(w_ev, res & w_ev->ev_events, 1);
! 198: }
! 199: }
! 200: check_selectop(sop);
! 201:
! 202: return (0);
! 203: }
! 204:
! 205:
! 206: static int
! 207: select_resize(struct selectop *sop, int fdsz)
! 208: {
! 209: int n_events, n_events_old;
! 210:
! 211: fd_set *readset_in = NULL;
! 212: fd_set *writeset_in = NULL;
! 213: fd_set *readset_out = NULL;
! 214: fd_set *writeset_out = NULL;
! 215: struct event **r_by_fd = NULL;
! 216: struct event **w_by_fd = NULL;
! 217:
! 218: n_events = (fdsz/sizeof(fd_mask)) * NFDBITS;
! 219: n_events_old = (sop->event_fdsz/sizeof(fd_mask)) * NFDBITS;
! 220:
! 221: if (sop->event_readset_in)
! 222: check_selectop(sop);
! 223:
! 224: if ((readset_in = realloc(sop->event_readset_in, fdsz)) == NULL)
! 225: goto error;
! 226: sop->event_readset_in = readset_in;
! 227: if ((readset_out = realloc(sop->event_readset_out, fdsz)) == NULL)
! 228: goto error;
! 229: sop->event_readset_out = readset_out;
! 230: if ((writeset_in = realloc(sop->event_writeset_in, fdsz)) == NULL)
! 231: goto error;
! 232: sop->event_writeset_in = writeset_in;
! 233: if ((writeset_out = realloc(sop->event_writeset_out, fdsz)) == NULL)
! 234: goto error;
! 235: sop->event_writeset_out = writeset_out;
! 236: if ((r_by_fd = realloc(sop->event_r_by_fd,
! 237: n_events*sizeof(struct event*))) == NULL)
! 238: goto error;
! 239: sop->event_r_by_fd = r_by_fd;
! 240: if ((w_by_fd = realloc(sop->event_w_by_fd,
! 241: n_events * sizeof(struct event*))) == NULL)
! 242: goto error;
! 243: sop->event_w_by_fd = w_by_fd;
! 244:
! 245: memset((char *)sop->event_readset_in + sop->event_fdsz, 0,
! 246: fdsz - sop->event_fdsz);
! 247: memset((char *)sop->event_writeset_in + sop->event_fdsz, 0,
! 248: fdsz - sop->event_fdsz);
! 249: memset(sop->event_r_by_fd + n_events_old, 0,
! 250: (n_events-n_events_old) * sizeof(struct event*));
! 251: memset(sop->event_w_by_fd + n_events_old, 0,
! 252: (n_events-n_events_old) * sizeof(struct event*));
! 253:
! 254: sop->event_fdsz = fdsz;
! 255: check_selectop(sop);
! 256:
! 257: return (0);
! 258:
! 259: error:
! 260: event_warn("malloc");
! 261: return (-1);
! 262: }
! 263:
! 264:
! 265: static int
! 266: select_add(void *arg, struct event *ev)
! 267: {
! 268: struct selectop *sop = arg;
! 269:
! 270: if (ev->ev_events & EV_SIGNAL)
! 271: return (evsignal_add(ev));
! 272:
! 273: check_selectop(sop);
! 274: /*
! 275: * Keep track of the highest fd, so that we can calculate the size
! 276: * of the fd_sets for select(2)
! 277: */
! 278: if (sop->event_fds < ev->ev_fd) {
! 279: int fdsz = sop->event_fdsz;
! 280:
! 281: if (fdsz < sizeof(fd_mask))
! 282: fdsz = sizeof(fd_mask);
! 283:
! 284: while (fdsz <
! 285: (howmany(ev->ev_fd + 1, NFDBITS) * sizeof(fd_mask)))
! 286: fdsz *= 2;
! 287:
! 288: if (fdsz != sop->event_fdsz) {
! 289: if (select_resize(sop, fdsz)) {
! 290: check_selectop(sop);
! 291: return (-1);
! 292: }
! 293: }
! 294:
! 295: sop->event_fds = ev->ev_fd;
! 296: }
! 297:
! 298: if (ev->ev_events & EV_READ) {
! 299: FD_SET(ev->ev_fd, sop->event_readset_in);
! 300: sop->event_r_by_fd[ev->ev_fd] = ev;
! 301: }
! 302: if (ev->ev_events & EV_WRITE) {
! 303: FD_SET(ev->ev_fd, sop->event_writeset_in);
! 304: sop->event_w_by_fd[ev->ev_fd] = ev;
! 305: }
! 306: check_selectop(sop);
! 307:
! 308: return (0);
! 309: }
! 310:
! 311: /*
! 312: * Nothing to be done here.
! 313: */
! 314:
! 315: static int
! 316: select_del(void *arg, struct event *ev)
! 317: {
! 318: struct selectop *sop = arg;
! 319:
! 320: check_selectop(sop);
! 321: if (ev->ev_events & EV_SIGNAL)
! 322: return (evsignal_del(ev));
! 323:
! 324: if (sop->event_fds < ev->ev_fd) {
! 325: check_selectop(sop);
! 326: return (0);
! 327: }
! 328:
! 329: if (ev->ev_events & EV_READ) {
! 330: FD_CLR(ev->ev_fd, sop->event_readset_in);
! 331: sop->event_r_by_fd[ev->ev_fd] = NULL;
! 332: }
! 333:
! 334: if (ev->ev_events & EV_WRITE) {
! 335: FD_CLR(ev->ev_fd, sop->event_writeset_in);
! 336: sop->event_w_by_fd[ev->ev_fd] = NULL;
! 337: }
! 338:
! 339: check_selectop(sop);
! 340: return (0);
! 341: }
! 342:
! 343: static void
! 344: select_dealloc(struct event_base *base, void *arg)
! 345: {
! 346: struct selectop *sop = arg;
! 347:
! 348: evsignal_dealloc(base);
! 349: if (sop->event_readset_in)
! 350: free(sop->event_readset_in);
! 351: if (sop->event_writeset_in)
! 352: free(sop->event_writeset_in);
! 353: if (sop->event_readset_out)
! 354: free(sop->event_readset_out);
! 355: if (sop->event_writeset_out)
! 356: free(sop->event_writeset_out);
! 357: if (sop->event_r_by_fd)
! 358: free(sop->event_r_by_fd);
! 359: if (sop->event_w_by_fd)
! 360: free(sop->event_w_by_fd);
! 361:
! 362: memset(sop, 0, sizeof(struct selectop));
! 363: free(sop);
! 364: }
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