freebsd-dev/lib/libkse/thread/thr_select.c
John Birrell 06ca87e9f7 Update the caller's descriptor masks even if there are none ready for
I/O for those applications that don't believe the return value of zero as
meaning that THERE ARE *NO* DESCRIPTORS READY.
1998-06-12 02:17:18 +00:00

178 lines
5.2 KiB
C

/*
* 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 REGENTS 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 <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/time.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
int
select(int numfds, fd_set * readfds, fd_set * writefds,
fd_set * exceptfds, struct timeval * timeout)
{
fd_set read_locks, write_locks, rdwr_locks;
struct timespec ts;
struct timeval zero_timeout = {0, 0};
int i, ret = 0, got_all_locks = 1;
struct pthread_select_data data;
if (numfds > _thread_dtablesize) {
numfds = _thread_dtablesize;
}
/* Check if a timeout was specified: */
if (timeout) {
/* Convert the timeval to a timespec: */
TIMEVAL_TO_TIMESPEC(timeout, &ts);
/* Set the wake up time: */
_thread_kern_set_timeout(&ts);
} else {
/* Wait for ever: */
_thread_kern_set_timeout(NULL);
}
FD_ZERO(&read_locks);
FD_ZERO(&write_locks);
FD_ZERO(&rdwr_locks);
/* lock readfds */
if (readfds || writefds || exceptfds) {
for (i = 0; i < numfds; i++) {
if ((readfds && (FD_ISSET(i, readfds))) || (exceptfds && FD_ISSET(i, exceptfds))) {
if (writefds && FD_ISSET(i, writefds)) {
if ((ret = _FD_LOCK(i, FD_RDWR, NULL)) != 0) {
got_all_locks = 0;
break;
}
FD_SET(i, &rdwr_locks);
} else {
if ((ret = _FD_LOCK(i, FD_READ, NULL)) != 0) {
got_all_locks = 0;
break;
}
FD_SET(i, &read_locks);
}
} else {
if (writefds && FD_ISSET(i, writefds)) {
if ((ret = _FD_LOCK(i, FD_WRITE, NULL)) != 0) {
got_all_locks = 0;
break;
}
FD_SET(i, &write_locks);
}
}
}
}
if (got_all_locks) {
data.nfds = numfds;
FD_ZERO(&data.readfds);
FD_ZERO(&data.writefds);
FD_ZERO(&data.exceptfds);
if (readfds != NULL) {
memcpy(&data.readfds, readfds, sizeof(data.readfds));
}
if (writefds != NULL) {
memcpy(&data.writefds, writefds, sizeof(data.writefds));
}
if (exceptfds != NULL) {
memcpy(&data.exceptfds, exceptfds, sizeof(data.exceptfds));
}
if ((ret = _thread_sys_select(data.nfds, &data.readfds, &data.writefds, &data.exceptfds, &zero_timeout)) == 0) {
data.nfds = numfds;
FD_ZERO(&data.readfds);
FD_ZERO(&data.writefds);
FD_ZERO(&data.exceptfds);
if (readfds != NULL) {
memcpy(&data.readfds, readfds, sizeof(data.readfds));
}
if (writefds != NULL) {
memcpy(&data.writefds, writefds, sizeof(data.writefds));
}
if (exceptfds != NULL) {
memcpy(&data.exceptfds, exceptfds, sizeof(data.exceptfds));
}
_thread_run->data.select_data = &data;
_thread_run->interrupted = 0;
_thread_kern_sched_state(PS_SELECT_WAIT, __FILE__, __LINE__);
if (_thread_run->interrupted) {
errno = EINTR;
ret = -1;
} else
ret = data.nfds;
}
}
/* clean up the locks */
for (i = 0; i < numfds; i++)
if (FD_ISSET(i, &read_locks))
_FD_UNLOCK(i, FD_READ);
for (i = 0; i < numfds; i++)
if (FD_ISSET(i, &rdwr_locks))
_FD_UNLOCK(i, FD_RDWR);
for (i = 0; i < numfds; i++)
if (FD_ISSET(i, &write_locks))
_FD_UNLOCK(i, FD_WRITE);
if (ret >= 0) {
if (readfds != NULL) {
for (i = 0; i < numfds; i++) {
if (FD_ISSET(i, readfds) &&
!FD_ISSET(i, &data.readfds)) {
FD_CLR(i, readfds);
}
}
}
if (writefds != NULL) {
for (i = 0; i < numfds; i++) {
if (FD_ISSET(i, writefds) &&
!FD_ISSET(i, &data.writefds)) {
FD_CLR(i, writefds);
}
}
}
if (exceptfds != NULL) {
for (i = 0; i < numfds; i++) {
if (FD_ISSET(i, exceptfds) &&
!FD_ISSET(i, &data.exceptfds)) {
FD_CLR(i, exceptfds);
}
}
}
}
return (ret);
}
#endif