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