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/* $Id: bsd-poll.c,v 1.4 2008/08/29 21:32:38 dtucker Exp $ */
/*
* Copyright (c) 2004, 2005, 2007 Darren Tucker (dtucker at zip com au).
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "includes.h"
#if !defined(HAVE_POLL)
#ifdef HAVE_SYS_SELECT_H
# include <sys/select.h>
#endif
#include <stdlib.h>
#include <errno.h>
#include "bsd-poll.h"
/*
* A minimal implementation of poll(2), built on top of select(2).
*
* Only supports POLLIN and POLLOUT flags in pfd.events, and POLLIN, POLLOUT
* and POLLERR flags in revents.
*
* Supports pfd.fd = -1 meaning "unused" although it's not standard.
*/
int
poll(struct pollfd *fds, nfds_t nfds, int timeout)
{
nfds_t i;
int saved_errno, ret, fd, maxfd = 0;
fd_set *readfds = NULL, *writefds = NULL, *exceptfds = NULL;
size_t nmemb;
struct timeval tv, *tvp = NULL;
for (i = 0; i < nfds; i++) {
fd = fds[i].fd;
if (fd >= FD_SETSIZE) {
errno = EINVAL;
return -1;
}
maxfd = MAX(maxfd, fd);
}
nmemb = howmany(maxfd + 1 , NFDBITS);
if ((readfds = calloc(nmemb, sizeof(fd_mask))) == NULL ||
(writefds = calloc(nmemb, sizeof(fd_mask))) == NULL ||
(exceptfds = calloc(nmemb, sizeof(fd_mask))) == NULL) {
saved_errno = ENOMEM;
ret = -1;
goto out;
}
/* populate event bit vectors for the events we're interested in */
for (i = 0; i < nfds; i++) {
fd = fds[i].fd;
if (fd == -1)
continue;
if (fds[i].events & POLLIN) {
FD_SET(fd, readfds);
FD_SET(fd, exceptfds);
}
if (fds[i].events & POLLOUT) {
FD_SET(fd, writefds);
FD_SET(fd, exceptfds);
}
}
/* poll timeout is msec, select is timeval (sec + usec) */
if (timeout >= 0) {
tv.tv_sec = timeout / 1000;
tv.tv_usec = (timeout % 1000) * 1000;
tvp = &tv;
}
ret = select(maxfd + 1, readfds, writefds, exceptfds, tvp);
saved_errno = errno;
/* scan through select results and set poll() flags */
for (i = 0; i < nfds; i++) {
fd = fds[i].fd;
fds[i].revents = 0;
if (fd == -1)
continue;
if (FD_ISSET(fd, readfds)) {
fds[i].revents |= POLLIN;
}
if (FD_ISSET(fd, writefds)) {
fds[i].revents |= POLLOUT;
}
if (FD_ISSET(fd, exceptfds)) {
fds[i].revents |= POLLERR;
}
}
out:
if (readfds != NULL)
free(readfds);
if (writefds != NULL)
free(writefds);
if (exceptfds != NULL)
free(exceptfds);
if (ret == -1)
errno = saved_errno;
return ret;
}
#endif
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