mariadb/mit-pthreads/pthreads/select.c
bk@work.mysql.com f4c589ff6c Import changeset
2000-07-31 21:29:14 +02:00

255 lines
7.8 KiB
C

/* ==== select.c ============================================================
* Copyright (c) 1994 by Chris Provenzano, proven@mit.edu
* 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 Chris Provenzano.
* 4. The name of Chris Provenzano may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO ``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 CHRIS PROVENZANO 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.
*
* This code based on code contributed by
* Peter Hofmann <peterh@prz.tu-berlin.d400.de>
*
* Description : Select.
*
* 1.23 94/04/26 proven
* -Started coding this file.
*/
#ifndef lint
static const char rcsid[] = "$Id$";
#endif
#include <string.h>
#include <errno.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/time.h>
extern struct pthread_queue fd_wait_select;
static struct timeval zero_timeout = { 0, 0 }; /* Moved by monty */
/* ==========================================================================
* select()
*/
int select(int numfds, fd_set *readfds, fd_set *writefds,
fd_set *exceptfds, struct timeval *timeout)
{
fd_set real_exceptfds, real_readfds, real_writefds; /* mapped fd_sets */
fd_set * real_readfds_p, * real_writefds_p, * real_exceptfds_p;
fd_set read_locks, write_locks, rdwr_locks;
struct timespec timeout_time, current_time;
int i, j, ret = 0, got_all_locks = 1;
struct pthread_select_data data;
if (numfds > dtablesize) {
numfds = dtablesize;
}
data.nfds = 0;
FD_ZERO(&data.readfds);
FD_ZERO(&data.writefds);
FD_ZERO(&data.exceptfds);
/* Do this first */
if (timeout) {
machdep_gettimeofday(&current_time);
timeout_time.tv_sec = current_time.tv_sec + timeout->tv_sec;
if ((timeout_time.tv_nsec = current_time.tv_nsec +
(timeout->tv_usec * 1000)) > 1000000000) {
timeout_time.tv_nsec -= 1000000000;
timeout_time.tv_sec++;
}
}
FD_ZERO(&read_locks);
FD_ZERO(&write_locks);
FD_ZERO(&rdwr_locks);
FD_ZERO(&real_readfds);
FD_ZERO(&real_writefds);
FD_ZERO(&real_exceptfds);
/* 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)) != OK) {
got_all_locks = 0;
break;
}
FD_SET(i, &rdwr_locks);
FD_SET(fd_table[i]->fd.i,&real_writefds);
} else {
if ((ret = fd_lock(i, FD_READ, NULL)) != OK) {
got_all_locks = 0;
break;
}
FD_SET(i, &read_locks);
}
if (readfds && FD_ISSET(i,readfds)) {
FD_SET(fd_table[i]->fd.i, &real_readfds);
}
if (exceptfds && FD_ISSET(i,exceptfds)) {
FD_SET(fd_table[i]->fd.i, &real_exceptfds);
}
if (fd_table[i]->fd.i >= data.nfds) {
data.nfds = fd_table[i]->fd.i + 1;
}
} else {
if (writefds && FD_ISSET(i, writefds)) {
if ((ret = fd_lock(i, FD_WRITE, NULL)) != OK) {
got_all_locks = 0;
break;
}
FD_SET(i, &write_locks);
FD_SET(fd_table[i]->fd.i,&real_writefds);
if (fd_table[i]->fd.i >= data.nfds) {
data.nfds = fd_table[i]->fd.i + 1;
}
}
}
}
}
if (got_all_locks)
{
memcpy(&data.readfds,&real_readfds,sizeof(fd_set));
memcpy(&data.writefds,&real_writefds,sizeof(fd_set));
memcpy(&data.exceptfds,&real_exceptfds,sizeof(fd_set));
real_readfds_p = (readfds == NULL) ? NULL : &real_readfds;
real_writefds_p = (writefds == NULL) ? NULL : &real_writefds;
real_exceptfds_p = (exceptfds == NULL) ? NULL : &real_exceptfds;
pthread_run->sighandled=0;
if ((ret = machdep_sys_select(data.nfds, real_readfds_p,
real_writefds_p, real_exceptfds_p,
&zero_timeout)) == OK) {
pthread_sched_prevent();
real_exceptfds_p = (exceptfds == NULL) ? NULL : &data.exceptfds;
real_writefds_p = (writefds == NULL) ? NULL : &data.writefds;
real_readfds_p = (readfds == NULL) ? NULL : &data.readfds;
pthread_queue_enq(&fd_wait_select, pthread_run);
pthread_run->data.select_data = &data;
SET_PF_WAIT_EVENT(pthread_run);
if (timeout) {
machdep_gettimeofday(&current_time);
sleep_schedule(&current_time, &timeout_time);
SET_PF_AT_CANCEL_POINT(pthread_run);
pthread_resched_resume(PS_SELECT_WAIT);
CLEAR_PF_AT_CANCEL_POINT(pthread_run);
/* We're awake */
if (sleep_cancel(pthread_run) == NOTOK) {
ret = OK;
}
else
{
int count = 0;
for (i = 0; i < numfds; i++)
{
if (real_readfds_p && (FD_ISSET(i, real_readfds_p)))
count++;
if (real_writefds_p && (FD_ISSET(i, real_writefds_p)))
count++;
if (real_exceptfds_p && (FD_ISSET(i, real_exceptfds_p)))
count++;
}
ret = count;
}
/* Moving this after the sleep_cancel() seemed
* to fix intermittent crashes during heavy
* socket use. (mevans)
*/
CLEAR_PF_DONE_EVENT(pthread_run);
} else {
int count = 0;
SET_PF_AT_CANCEL_POINT(pthread_run);
pthread_resched_resume(PS_SELECT_WAIT);
CLEAR_PF_AT_CANCEL_POINT(pthread_run);
CLEAR_PF_DONE_EVENT(pthread_run);
for (i = 0; i < numfds; i++)
{
if (real_readfds_p && (FD_ISSET(i, real_readfds_p)))
count++;
if (real_writefds_p && (FD_ISSET(i, real_writefds_p)))
count++;
if (real_exceptfds_p && (FD_ISSET(i, real_exceptfds_p)))
count++;
}
ret = count;
}
if (pthread_run->sighandled) /* Added by monty */
{ /* We where aborted */
ret= NOTOK;
SET_ERRNO(EINTR);
}
} else if (ret < 0) {
SET_ERRNO(-ret);
ret = NOTOK;
}
}
/* clean up the locks */
for (i = 0; i < numfds; i++)
{ /* Changed by monty */
if (FD_ISSET(i,&read_locks)) fd_unlock(i,FD_READ);
if (FD_ISSET(i,&rdwr_locks)) fd_unlock(i,FD_RDWR);
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(fd_table[i]->fd.i,real_readfds_p)))
FD_CLR(i,readfds);
}
}
if (writefds != NULL) {
for (i = 0; i < numfds; i++)
if (! (FD_ISSET(i,writefds) &&
FD_ISSET(fd_table[i]->fd.i,real_writefds_p)))
FD_CLR(i,writefds);
}
if (exceptfds != NULL) {
for (i = 0; i < numfds; i++)
if (! (FD_ISSET(i,exceptfds) &&
FD_ISSET(fd_table[i]->fd.i,real_exceptfds_p)))
FD_CLR(i,exceptfds);
}
} else {
if (exceptfds != NULL) FD_ZERO(exceptfds);
if (writefds != NULL) FD_ZERO(writefds);
if (readfds != NULL) FD_ZERO(readfds);
}
return(ret);
}