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  * $DragonFly: src/lib/libc_r/uthread/uthread_select.c,v 1.2 2003/06/17 06:26:48 dillon Exp $
  34  */
  35 #include <unistd.h>
  36 #include <errno.h>
  37 #include <poll.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <sys/param.h>
  41 #include <sys/types.h>
  42 #include <sys/time.h>
  43 #include <sys/fcntl.h>
  44 #include <pthread.h>
  45 #include "pthread_private.h"
  46
  47 int
  48 _select(int numfds, fd_set * readfds, fd_set * writefds, fd_set * exceptfds,
  49     struct timeval * timeout)
  50 {
  51         struct pthread  *curthread = _get_curthread();
  52         struct timespec ts;
  53         int             i, ret = 0, f_wait = 1;
  54         int             pfd_index, got_events = 0, fd_count = 0;
  55         struct pthread_poll_data data;
  56
  57         if (numfds > _thread_dtablesize) {
  58                 numfds = _thread_dtablesize;
  59         }
  60         /* Check if a timeout was specified: */
  61         if (timeout) {
  62                 if (timeout->tv_sec < 0 ||
  63                         timeout->tv_usec < 0 || timeout->tv_usec >= 1000000) {
  64                         errno = EINVAL;
  65                         return (-1);
  66                 }
  67
  68                 /* Convert the timeval to a timespec: */
  69                 TIMEVAL_TO_TIMESPEC(timeout, &ts);
  70
  71                 /* Set the wake up time: */
  72                 _thread_kern_set_timeout(&ts);
  73                 if (ts.tv_sec == 0 && ts.tv_nsec == 0)
  74                         f_wait = 0;
  75         } else {
  76                 /* Wait for ever: */
  77                 _thread_kern_set_timeout(NULL);
  78         }
  79
  80         /* Count the number of file descriptors to be polled: */
  81         if (readfds || writefds || exceptfds) {
  82                 for (i = 0; i < numfds; i++) {
  83                         if ((readfds && FD_ISSET(i, readfds)) ||
  84                             (exceptfds && FD_ISSET(i, exceptfds)) ||
  85                             (writefds && FD_ISSET(i, writefds))) {
  86                                 fd_count++;
  87                         }
  88                 }
  89         }
  90
  91         /*
  92          * Allocate memory for poll data if it hasn't already been
  93          * allocated or if previously allocated memory is insufficient.
  94          */
  95         if ((curthread->poll_data.fds == NULL) ||
  96             (curthread->poll_data.nfds < fd_count)) {
  97                 data.fds = (struct pollfd *) realloc(curthread->poll_data.fds,
  98                     sizeof(struct pollfd) * MAX(128, fd_count));
  99                 if (data.fds == NULL) {
 100                         errno = ENOMEM;
 101                         ret = -1;
 102                 }
 103                 else {
 104                         /*
 105                          * Note that the threads poll data always
 106                          * indicates what is allocated, not what is
 107                          * currently being polled.
 108                          */
 109                         curthread->poll_data.fds = data.fds;
 110                         curthread->poll_data.nfds = MAX(128, fd_count);
 111                 }
 112         }
 113         if (ret == 0) {
 114                 /* Setup the wait data. */
 115                 data.fds = curthread->poll_data.fds;
 116                 data.nfds = fd_count;
 117
 118                 /*
 119                  * Setup the array of pollfds.  Optimize this by
 120                  * running the loop in reverse and stopping when
 121                  * the number of selected file descriptors is reached.
 122                  */
 123                 for (i = numfds - 1, pfd_index = fd_count - 1;
 124                     (i >= 0) && (pfd_index >= 0); i--) {
 125                         data.fds[pfd_index].events = 0;
 126                         if (readfds && FD_ISSET(i, readfds)) {
 127                                 data.fds[pfd_index].events = POLLRDNORM;
 128                         }
 129                         if (exceptfds && FD_ISSET(i, exceptfds)) {
 130                                 data.fds[pfd_index].events |= POLLRDBAND;
 131                         }
 132                         if (writefds && FD_ISSET(i, writefds)) {
 133                                 data.fds[pfd_index].events |= POLLWRNORM;
 134                         }
 135                         if (data.fds[pfd_index].events != 0) {
 136                                 /*
 137                                  * Set the file descriptor to be polled and
 138                                  * clear revents in case of a timeout which
 139                                  * leaves fds unchanged:
 140                                  */
 141                                 data.fds[pfd_index].fd = i;
 142                                 data.fds[pfd_index].revents = 0;
 143                                 pfd_index--;
 144                         }
 145                 }
 146                 if (((ret = __sys_poll(data.fds, data.nfds, 0)) == 0) &&
 147                    (f_wait != 0)) {
 148                         curthread->data.poll_data = &data;
 149                         curthread->interrupted = 0;
 150                         _thread_kern_sched_state(PS_SELECT_WAIT, __FILE__, __LINE__);
 151                         if (curthread->interrupted) {
 152                                 errno = EINTR;
 153                                 data.nfds = 0;
 154                                 ret = -1;
 155                         } else
 156                                 ret = data.nfds;
 157                 }
 158         }
 159
 160         if (ret >= 0) {
 161                 numfds = 0;
 162                 for (i = 0; i < fd_count; i++) {
 163                         /*
 164                          * Check the results of the poll and clear
 165                          * this file descriptor from the fdset if
 166                          * the requested event wasn't ready.
 167                          */
 168
 169                         /*
 170                          * First check for invalid descriptor.
 171                          * If found, set errno and return -1.
 172                          */
 173                         if (data.fds[i].revents & POLLNVAL) {
 174                                 errno = EBADF;
 175                                 return -1;
 176                         }
 177
 178                         got_events = 0;
 179                         if (readfds != NULL) {
 180                                 if (FD_ISSET(data.fds[i].fd, readfds)) {
 181                                         if ((data.fds[i].revents & (POLLIN
 182                                             | POLLRDNORM | POLLERR
 183                                             | POLLHUP | POLLNVAL)) != 0)
 184                                                 got_events++;
 185                                         else
 186                                                 FD_CLR(data.fds[i].fd, readfds);
 187                                 }
 188                         }
 189                         if (writefds != NULL) {
 190                                 if (FD_ISSET(data.fds[i].fd, writefds)) {
 191                                         if ((data.fds[i].revents & (POLLOUT
 192                                             | POLLWRNORM | POLLWRBAND | POLLERR
 193                                             | POLLHUP | POLLNVAL)) != 0)
 194                                                 got_events++;
 195                                         else
 196                                                 FD_CLR(data.fds[i].fd,
 197                                                     writefds);
 198                                 }
 199                         }
 200                         if (exceptfds != NULL) {
 201                                 if (FD_ISSET(data.fds[i].fd, exceptfds)) {
 202                                         if (data.fds[i].revents & (POLLRDBAND |
 203                                             POLLPRI))
 204                                                 got_events++;
 205                                         else
 206                                                 FD_CLR(data.fds[i].fd,
 207                                                     exceptfds);
 208                                 }
 209                         }
 210                         if (got_events != 0)
 211                                 numfds+=got_events;
 212                 }
 213                 ret = numfds;
 214         }
 215
 216         return (ret);
 217 }
 218
 219 int
 220 select(int numfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 221         struct timeval *timeout)
 222 {
 223         int ret;
 224
 225         _thread_enter_cancellation_point();
 226         ret = _select(numfds, readfds, writefds, exceptfds, timeout);
 227         _thread_leave_cancellation_point();
 228
 229         return ret;
 230 }