lib/libc_r/uthread/uthread_select.c

   1 /*
   2  * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by John Birrell.
  16  * 4. Neither the name of the author nor the names of any co-contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  * $FreeBSD: src/lib/libc_r/uthread/uthread_select.c,v 1.16.2.5 2002/10/22 14:44:03 fjoe Exp $
  33  */
  34 #include <unistd.h>
  35 #include <errno.h>
  36 #include <poll.h>
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include <sys/param.h>
  40 #include <sys/types.h>
  41 #include <sys/time.h>
  42 #include <sys/fcntl.h>
  43 #include <pthread.h>
  44 #include "pthread_private.h"
  45
  46 int
  47 _select(int numfds, fd_set * readfds, fd_set * writefds, fd_set * exceptfds,
  48     struct timeval * timeout)
  49 {
  50         struct pthread  *curthread = _get_curthread();
  51         struct timespec ts;
  52         int             i, ret = 0, f_wait = 1;
  53         int             pfd_index, got_events = 0, fd_count = 0;
  54         struct pthread_poll_data data;
  55
  56         if (numfds > _thread_dtablesize) {
  57                 numfds = _thread_dtablesize;
  58         }
  59         /* Check if a timeout was specified: */
  60         if (timeout) {
  61                 if (timeout->tv_sec < 0 ||
  62                         timeout->tv_usec < 0 || timeout->tv_usec >= 1000000) {
  63                         errno = EINVAL;
  64                         return (-1);
  65                 }
  66
  67                 /* Convert the timeval to a timespec: */
  68                 TIMEVAL_TO_TIMESPEC(timeout, &ts);
  69
  70                 /* Set the wake up time: */
  71                 _thread_kern_set_timeout(&ts);
  72                 if (ts.tv_sec == 0 && ts.tv_nsec == 0)
  73                         f_wait = 0;
  74         } else {
  75                 /* Wait for ever: */
  76                 _thread_kern_set_timeout(NULL);
  77         }
  78
  79         /* Count the number of file descriptors to be polled: */
  80         if (readfds || writefds || exceptfds) {
  81                 for (i = 0; i < numfds; i++) {
  82                         if ((readfds && FD_ISSET(i, readfds)) ||
  83                             (exceptfds && FD_ISSET(i, exceptfds)) ||
  84                             (writefds && FD_ISSET(i, writefds))) {
  85                                 fd_count++;
  86                         }
  87                 }
  88         }
  89
  90         /*
  91          * Allocate memory for poll data if it hasn't already been
  92          * allocated or if previously allocated memory is insufficient.
  93          */
  94         if ((curthread->poll_data.fds == NULL) ||
  95             (curthread->poll_data.nfds < fd_count)) {
  96                 data.fds = (struct pollfd *) realloc(curthread->poll_data.fds,
  97                     sizeof(struct pollfd) * MAX(128, fd_count));
  98                 if (data.fds == NULL) {
  99                         errno = ENOMEM;
 100                         ret = -1;
 101                 }
 102                 else {
 103                         /*
 104                          * Note that the threads poll data always
 105                          * indicates what is allocated, not what is
 106                          * currently being polled.
 107                          */
 108                         curthread->poll_data.fds = data.fds;
 109                         curthread->poll_data.nfds = MAX(128, fd_count);
 110                 }
 111         }
 112         if (ret == 0) {
 113                 /* Setup the wait data. */
 114                 data.fds = curthread->poll_data.fds;
 115                 data.nfds = fd_count;
 116
 117                 /*
 118                  * Setup the array of pollfds.  Optimize this by
 119                  * running the loop in reverse and stopping when
 120                  * the number of selected file descriptors is reached.
 121                  */
 122                 for (i = numfds - 1, pfd_index = fd_count - 1;
 123                     (i >= 0) && (pfd_index >= 0); i--) {
 124                         data.fds[pfd_index].events = 0;
 125                         if (readfds && FD_ISSET(i, readfds)) {
 126                                 data.fds[pfd_index].events = POLLRDNORM;
 127                         }
 128                         if (exceptfds && FD_ISSET(i, exceptfds)) {
 129                                 data.fds[pfd_index].events |= POLLRDBAND;
 130                         }
 131                         if (writefds && FD_ISSET(i, writefds)) {
 132                                 data.fds[pfd_index].events |= POLLWRNORM;
 133                         }
 134                         if (data.fds[pfd_index].events != 0) {
 135                                 /*
 136                                  * Set the file descriptor to be polled and
 137                                  * clear revents in case of a timeout which
 138                                  * leaves fds unchanged:
 139                                  */
 140                                 data.fds[pfd_index].fd = i;
 141                                 data.fds[pfd_index].revents = 0;
 142                                 pfd_index--;
 143                         }
 144                 }
 145                 if (((ret = __sys_poll(data.fds, data.nfds, 0)) == 0) &&
 146                    (f_wait != 0)) {
 147                         curthread->data.poll_data = &data;
 148                         curthread->interrupted = 0;
 149                         _thread_kern_sched_state(PS_SELECT_WAIT, __FILE__, __LINE__);
 150                         if (curthread->interrupted) {
 151                                 errno = EINTR;
 152                                 data.nfds = 0;
 153                                 ret = -1;
 154                         } else
 155                                 ret = data.nfds;
 156                 }
 157         }
 158
 159         if (ret >= 0) {
 160                 numfds = 0;
 161                 for (i = 0; i < fd_count; i++) {
 162                         /*
 163                          * Check the results of the poll and clear
 164                          * this file descriptor from the fdset if
 165                          * the requested event wasn't ready.
 166                          */
 167
 168                         /*
 169                          * First check for invalid descriptor.
 170                          * If found, set errno and return -1.
 171                          */
 172                         if (data.fds[i].revents & POLLNVAL) {
 173                                 errno = EBADF;
 174                                 return -1;
 175                         }
 176
 177                         got_events = 0;
 178                         if (readfds != NULL) {
 179                                 if (FD_ISSET(data.fds[i].fd, readfds)) {
 180                                         if ((data.fds[i].revents & (POLLIN
 181                                             | POLLRDNORM | POLLERR
 182                                             | POLLHUP | POLLNVAL)) != 0)
 183                                                 got_events++;
 184                                         else
 185                                                 FD_CLR(data.fds[i].fd, readfds);
 186                                 }
 187                         }
 188                         if (writefds != NULL) {
 189                                 if (FD_ISSET(data.fds[i].fd, writefds)) {
 190                                         if ((data.fds[i].revents & (POLLOUT
 191                                             | POLLWRNORM | POLLWRBAND | POLLERR
 192                                             | POLLHUP | POLLNVAL)) != 0)
 193                                                 got_events++;
 194                                         else
 195                                                 FD_CLR(data.fds[i].fd,
 196                                                     writefds);
 197                                 }
 198                         }
 199                         if (exceptfds != NULL) {
 200                                 if (FD_ISSET(data.fds[i].fd, exceptfds)) {
 201                                         if (data.fds[i].revents & (POLLRDBAND |
 202                                             POLLPRI))
 203                                                 got_events++;
 204                                         else
 205                                                 FD_CLR(data.fds[i].fd,
 206                                                     exceptfds);
 207                                 }
 208                         }
 209                         if (got_events != 0)
 210                                 numfds+=got_events;
 211                 }
 212                 ret = numfds;
 213         }
 214
 215         return (ret);
 216 }
 217
 218 int
 219 select(int numfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 220         struct timeval *timeout)
 221 {
 222         int ret;
 223
 224         _thread_enter_cancellation_point();
 225         ret = _select(numfds, readfds, writefds, exceptfds, timeout);
 226         _thread_leave_cancellation_point();
 227
 228         return ret;
 229 }