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/* $OpenBSD: uthread_select.c,v 1.16 2007/05/21 16:50:36 kurt Exp $ */
/*
* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
* All rights reserved.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL 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 AUTHOR 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.
*
* $FreeBSD: uthread_select.c,v 1.13 1999/08/30 00:02:08 deischen Exp $
*/
#include <unistd.h>
#include <errno.h>
#include <poll.h>
#include <stdlib.h>
#include <string.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/fcntl.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
/*
* Minimum number of poll_data entries to allocate
*/
#define POLLDATA_MIN 128
int
select(int numfds, fd_set * readfds, fd_set * writefds,
fd_set * exceptfds, struct timeval * timeout)
{
struct pthread *curthread = _get_curthread();
struct timespec ts;
int bit, i, j, ret = 0, f_wait = 1;
short events;
int got_events = 0, fd_count = 0;
struct pthread_poll_data data;
fd_mask mask, rmask, wmask, emask;
/* This is a cancellation point: */
_thread_enter_cancellation_point();
if (numfds > _thread_max_fdtsize) {
numfds = _thread_max_fdtsize;
}
/* Check if a timeout was specified: */
if (timeout) {
if (timeout->tv_sec < 0 ||
timeout->tv_usec < 0 || timeout->tv_usec >= 1000000) {
errno = EINVAL;
ret = -1;
goto done;
}
/* Convert the timeval to a timespec: */
TIMEVAL_TO_TIMESPEC(timeout, &ts);
/* Set the wake up time: */
_thread_kern_set_timeout(&ts);
if (ts.tv_sec == 0 && ts.tv_nsec == 0)
f_wait = 0;
} else {
/* Wait for ever: */
_thread_kern_set_timeout(NULL);
}
/* Count the number of file descriptors to be polled: */
if (numfds && (readfds || writefds || exceptfds)) {
for (i = (numfds - 1) / (int)NFDBITS; i >= 0; i--) {
rmask = readfds ? readfds->fds_bits[i] : 0;
wmask = writefds ? writefds->fds_bits[i] : 0;
emask = exceptfds ? exceptfds->fds_bits[i] : 0;
mask = rmask | wmask | emask;
for (; (bit = ffs(mask)); mask ^= (1 << (bit - 1)))
fd_count++;
}
}
/*
* Allocate memory for poll data if it hasn't already been
* allocated or if previously allocated memory is insufficient.
*/
if ((curthread->poll_data.fds == NULL) ||
(curthread->poll_data.nfds < (nfds_t)fd_count)) {
data.fds = (struct pollfd *) realloc(curthread->poll_data.fds,
sizeof(struct pollfd) * (size_t)MAX(POLLDATA_MIN, fd_count));
if (data.fds == NULL) {
errno = ENOMEM;
ret = -1;
}
else {
/*
* Note that the threads poll data always
* indicates what is allocated, not what is
* currently being polled.
*/
curthread->poll_data.fds = data.fds;
curthread->poll_data.nfds = (nfds_t)MAX(POLLDATA_MIN, fd_count);
}
}
if (ret == 0) {
/* Setup the wait data. */
data.fds = curthread->poll_data.fds;
data.nfds = (nfds_t)fd_count;
/*
* Setup the array of pollfds. Optimize this by
* running the loop in reverse and stopping when
* the number of selected file descriptors is reached.
*/
for (i = (numfds - 1) / (int)NFDBITS, j = fd_count;
j != 0 && i >= 0; i--) {
rmask = readfds ? readfds->fds_bits[i] : 0;
wmask = writefds ? writefds->fds_bits[i] : 0;
emask = exceptfds ? exceptfds->fds_bits[i] : 0;
mask = rmask | wmask | emask;
while ((bit = ffs(mask))) {
int n = 1 << (bit - 1);
mask ^= n;
events = 0;
if (rmask & n)
events |= POLLRDNORM;
if (wmask & n)
events |= POLLWRNORM;
if (emask & n)
events |= POLLRDBAND;
if (events != 0) {
/*
* Set the file descriptor to be polled
* and clear revents in case of a
* timeout which leaves fds unchanged:
*/
data.fds[--j].fd =
(i * (int)NFDBITS) + bit - 1;
data.fds[j].events = events;
data.fds[j].revents = 0;
}
}
}
if (((ret = _thread_sys_poll(data.fds, data.nfds, 0)) == 0) &&
(f_wait != 0)) {
curthread->data.poll_data = &data;
curthread->interrupted = 0;
_thread_kern_sched_state(PS_SELECT_WAIT, __FILE__, __LINE__);
if (curthread->interrupted) {
errno = EINTR;
data.nfds = 0;
ret = -1;
} else
ret = (int)data.nfds;
}
}
if (ret >= 0) {
numfds = 0;
for (i = 0; i < fd_count; i++) {
/*
* Check the results of the poll and clear
* this file descriptor from the fdset if
* the requested event wasn't ready.
*/
/*
* First check for invalid descriptor.
* If found, set errno and return -1.
*/
if (data.fds[i].revents & POLLNVAL) {
errno = EBADF;
ret = -1;
goto done;
}
got_events = 0;
if (readfds != NULL) {
if (FD_ISSET(data.fds[i].fd, readfds)) {
if ((data.fds[i].revents & (POLLIN
| POLLRDNORM | POLLERR
| POLLHUP)) != 0)
got_events++;
else
FD_CLR(data.fds[i].fd, readfds);
}
}
if (writefds != NULL) {
if (FD_ISSET(data.fds[i].fd, writefds)) {
if ((data.fds[i].revents & (POLLOUT
| POLLWRNORM | POLLWRBAND | POLLERR
| POLLHUP)) != 0)
got_events++;
else
FD_CLR(data.fds[i].fd,
writefds);
}
}
if (exceptfds != NULL) {
if (FD_ISSET(data.fds[i].fd, exceptfds)) {
if (data.fds[i].revents & (POLLRDBAND |
POLLPRI))
got_events++;
else
FD_CLR(data.fds[i].fd,
exceptfds);
}
}
if (got_events != 0)
numfds+=got_events;
}
ret = numfds;
}
done:
/* No longer in a cancellation point: */
_thread_leave_cancellation_point();
return (ret);
}
#endif
|
