minix3/lib/libc/sys/poll.c

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2020-02-21 00:59:27 +05:30
/* $NetBSD: poll.c,v 1.3 2008/04/29 05:46:08 martin Exp $ */
/*-
* Copyright (c) 2003 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Charles Blundell.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#include "namespace.h"
#include <lib.h>
#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>
#include <sys/poll.h>
#include <errno.h>
int
poll(struct pollfd *p, nfds_t nfds, int timout)
{
fd_set rd, wr, except;
struct timeval tv;
nfds_t i;
int highfd, rval;
/*
* select cannot tell us much wrt POLL*BAND, POLLPRI, POLLHUP or
* POLLNVAL.
*/
FD_ZERO(&rd);
FD_ZERO(&wr);
FD_ZERO(&except);
highfd = -1;
for (i = 0; i < nfds; i++) {
if (p[i].fd < 0)
continue;
if (p[i].fd >= FD_SETSIZE) {
errno = EINVAL;
return -1;
}
if (p[i].fd > highfd)
highfd = p[i].fd;
if (p[i].events & (POLLIN|POLLRDNORM|POLLRDBAND|POLLPRI))
FD_SET(p[i].fd, &rd);
if (p[i].events & (POLLOUT|POLLWRNORM|POLLWRBAND))
FD_SET(p[i].fd, &wr);
FD_SET(p[i].fd, &except);
}
tv.tv_sec = timout / 1000;
tv.tv_usec = (timout % 1000) * 1000;
rval = select(highfd + 1, &rd, &wr, &except,
timout == -1 ? NULL : &tv);
if (rval <= 0)
return rval;
rval = 0;
for (i = 0; i < nfds; i++) {
p[i].revents = 0;
if (FD_ISSET(p[i].fd, &rd))
p[i].revents |= POLLIN|POLLRDNORM|POLLRDBAND|POLLPRI;
if (FD_ISSET(p[i].fd, &wr))
p[i].revents |= POLLOUT|POLLWRNORM|POLLWRBAND;
if (FD_ISSET(p[i].fd, &except))
p[i].revents |= POLLERR;
/* XXX: POLLHUP/POLLNVAL? */
if (p[i].revents != 0)
rval++;
}
return rval;
}