thr_select.c revision 48046
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 REGENTS 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 * $Id$ 33 */ 34#include <unistd.h> 35#include <errno.h> 36#include <poll.h> 37#include <string.h> 38#include <sys/param.h> 39#include <sys/types.h> 40#include <sys/time.h> 41#include <sys/fcntl.h> 42#ifdef _THREAD_SAFE 43#include <pthread.h> 44#include "pthread_private.h" 45 46int 47select(int numfds, fd_set * readfds, fd_set * writefds, 48 fd_set * exceptfds, struct timeval * timeout) 49{ 50 struct timespec ts; 51 int i, ret = 0, f_wait = 1; 52 int pfd_index, got_one = 0, fd_count = 0; 53 struct pthread_poll_data data; 54 55 if (numfds > _thread_dtablesize) { 56 numfds = _thread_dtablesize; 57 } 58 /* Check if a timeout was specified: */ 59 if (timeout) { 60 /* Convert the timeval to a timespec: */ 61 TIMEVAL_TO_TIMESPEC(timeout, &ts); 62 63 /* Set the wake up time: */ 64 _thread_kern_set_timeout(&ts); 65 if (ts.tv_sec == 0 && ts.tv_nsec == 0) 66 f_wait = 0; 67 } else { 68 /* Wait for ever: */ 69 _thread_kern_set_timeout(NULL); 70 } 71 72 /* Count the number of file descriptors to be polled: */ 73 if (readfds || writefds || exceptfds) { 74 for (i = 0; i < numfds; i++) { 75 if ((readfds && FD_ISSET(i, readfds)) || 76 (exceptfds && FD_ISSET(i, exceptfds)) || 77 (writefds && FD_ISSET(i, writefds))) { 78 fd_count++; 79 } 80 } 81 } 82 83 /* 84 * Allocate memory for poll data if it hasn't already been 85 * allocated or if previously allocated memory is insufficient. 86 */ 87 if ((_thread_run->poll_data.fds == NULL) || 88 (_thread_run->poll_data.nfds < fd_count)) { 89 data.fds = (struct pollfd *) realloc(_thread_run->poll_data.fds, 90 sizeof(struct pollfd) * MAX(128, fd_count)); 91 if (data.fds == NULL) { 92 errno = ENOMEM; 93 ret = -1; 94 } 95 else { 96 /* 97 * Note that the threads poll data always 98 * indicates what is allocated, not what is 99 * currently being polled. 100 */ 101 _thread_run->poll_data.fds = data.fds; 102 _thread_run->poll_data.nfds = MAX(128, fd_count); 103 } 104 } 105 if (ret == 0) { 106 /* Setup the wait data. */ 107 data.fds = _thread_run->poll_data.fds; 108 data.nfds = fd_count; 109 110 /* 111 * Setup the array of pollfds. Optimize this by 112 * running the loop in reverse and stopping when 113 * the number of selected file descriptors is reached. 114 */ 115 for (i = numfds - 1, pfd_index = fd_count - 1; 116 (i >= 0) && (pfd_index >= 0); i--) { 117 data.fds[pfd_index].events = 0; 118 if (readfds && FD_ISSET(i, readfds)) { 119 data.fds[pfd_index].events = POLLRDNORM; 120 } 121 if (exceptfds && FD_ISSET(i, exceptfds)) { 122 data.fds[pfd_index].events |= POLLRDBAND; 123 } 124 if (writefds && FD_ISSET(i, writefds)) { 125 data.fds[pfd_index].events |= POLLWRNORM; 126 } 127 if (data.fds[pfd_index].events != 0) { 128 /* 129 * Set the file descriptor to be polled and 130 * clear revents in case of a timeout which 131 * leaves fds unchanged: 132 */ 133 data.fds[pfd_index].fd = i; 134 data.fds[pfd_index].revents = 0; 135 pfd_index--; 136 } 137 } 138 if (((ret = _thread_sys_poll(data.fds, data.nfds, 0)) == 0) && 139 (f_wait != 0)) { 140 _thread_run->data.poll_data = &data; 141 _thread_run->interrupted = 0; 142 _thread_kern_sched_state(PS_SELECT_WAIT, __FILE__, __LINE__); 143 if (_thread_run->interrupted) { 144 errno = EINTR; 145 data.nfds = 0; 146 ret = -1; 147 } else 148 ret = data.nfds; 149 } 150 } 151 152 if (ret >= 0) { 153 numfds = 0; 154 for (i = 0; i < fd_count; i++) { 155 /* 156 * Check the results of the poll and clear 157 * this file descriptor from the fdset if 158 * the requested event wasn't ready. 159 */ 160 got_one = 0; 161 if (readfds != NULL) { 162 if (FD_ISSET(data.fds[i].fd, readfds)) { 163 if (data.fds[i].revents & (POLLIN | 164 POLLRDNORM)) 165 got_one = 1; 166 else 167 FD_CLR(data.fds[i].fd, readfds); 168 } 169 } 170 if (writefds != NULL) { 171 if (FD_ISSET(data.fds[i].fd, writefds)) { 172 if (data.fds[i].revents & (POLLOUT | 173 POLLWRNORM | POLLWRBAND)) 174 got_one = 1; 175 else 176 FD_CLR(data.fds[i].fd, 177 writefds); 178 } 179 } 180 if (exceptfds != NULL) { 181 if (FD_ISSET(data.fds[i].fd, exceptfds)) { 182 if (data.fds[i].revents & (POLLRDBAND | 183 POLLPRI | POLLHUP | POLLERR | 184 POLLNVAL)) 185 got_one = 1; 186 else 187 FD_CLR(data.fds[i].fd, 188 exceptfds); 189 } 190 } 191 if (got_one) 192 numfds++; 193 } 194 ret = numfds; 195 } 196 197 return (ret); 198} 199#endif 200