1 /* $Id: bsd-poll.c,v 1.6 2014/02/05 23:44:13 dtucker Exp $ */
4 * Copyright (c) 2004, 2005, 2007 Darren Tucker (dtucker at zip com au).
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
20 #if !defined(HAVE_POLL)
22 #include <sys/types.h>
24 #ifdef HAVE_SYS_SELECT_H
25 # include <sys/select.h>
34 * A minimal implementation of poll(2), built on top of select(2).
36 * Only supports POLLIN and POLLOUT flags in pfd.events, and POLLIN, POLLOUT
37 * and POLLERR flags in revents.
39 * Supports pfd.fd = -1 meaning "unused" although it's not standard.
43 poll(struct pollfd *fds, nfds_t nfds, int timeout)
46 int saved_errno, ret, fd, maxfd = 0;
47 fd_set *readfds = NULL, *writefds = NULL, *exceptfds = NULL;
49 struct timeval tv, *tvp = NULL;
51 for (i = 0; i < nfds; i++) {
53 if (fd >= FD_SETSIZE) {
57 maxfd = MAX(maxfd, fd);
60 nmemb = howmany(maxfd + 1 , NFDBITS);
61 if ((readfds = calloc(nmemb, sizeof(fd_mask))) == NULL ||
62 (writefds = calloc(nmemb, sizeof(fd_mask))) == NULL ||
63 (exceptfds = calloc(nmemb, sizeof(fd_mask))) == NULL) {
69 /* populate event bit vectors for the events we're interested in */
70 for (i = 0; i < nfds; i++) {
74 if (fds[i].events & POLLIN) {
76 FD_SET(fd, exceptfds);
78 if (fds[i].events & POLLOUT) {
80 FD_SET(fd, exceptfds);
84 /* poll timeout is msec, select is timeval (sec + usec) */
86 tv.tv_sec = timeout / 1000;
87 tv.tv_usec = (timeout % 1000) * 1000;
91 ret = select(maxfd + 1, readfds, writefds, exceptfds, tvp);
94 /* scan through select results and set poll() flags */
95 for (i = 0; i < nfds; i++) {
100 if (FD_ISSET(fd, readfds)) {
101 fds[i].revents |= POLLIN;
103 if (FD_ISSET(fd, writefds)) {
104 fds[i].revents |= POLLOUT;
106 if (FD_ISSET(fd, exceptfds)) {
107 fds[i].revents |= POLLERR;