thr_select.c revision 50476
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: head/lib/libkse/thread/thr_select.c 50476 1999-08-28 00:22:10Z peter $ 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#ifdef _THREAD_SAFE 44#include <pthread.h> 45#include "pthread_private.h" 46 47int 48select(int numfds, fd_set * readfds, fd_set * writefds, 49 fd_set * exceptfds, struct timeval * timeout) 50{ 51 struct timespec ts; 52 int i, ret = 0, f_wait = 1; 53 int pfd_index, got_one = 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 return (EINVAL); 64 65 /* Convert the timeval to a timespec: */ 66 TIMEVAL_TO_TIMESPEC(timeout, &ts); 67 68 /* Set the wake up time: */ 69 _thread_kern_set_timeout(&ts); 70 if (ts.tv_sec == 0 && ts.tv_nsec == 0) 71 f_wait = 0; 72 } else { 73 /* Wait for ever: */ 74 _thread_kern_set_timeout(NULL); 75 } 76 77 /* Count the number of file descriptors to be polled: */ 78 if (readfds || writefds || exceptfds) { 79 for (i = 0; i < numfds; i++) { 80 if ((readfds && FD_ISSET(i, readfds)) || 81 (exceptfds && FD_ISSET(i, exceptfds)) || 82 (writefds && FD_ISSET(i, writefds))) { 83 fd_count++; 84 } 85 } 86 } 87 88 /* 89 * Allocate memory for poll data if it hasn't already been 90 * allocated or if previously allocated memory is insufficient. 91 */ 92 if ((_thread_run->poll_data.fds == NULL) || 93 (_thread_run->poll_data.nfds < fd_count)) { 94 data.fds = (struct pollfd *) realloc(_thread_run->poll_data.fds, 95 sizeof(struct pollfd) * MAX(128, fd_count)); 96 if (data.fds == NULL) { 97 errno = ENOMEM; 98 ret = -1; 99 } 100 else { 101 /* 102 * Note that the threads poll data always 103 * indicates what is allocated, not what is 104 * currently being polled. 105 */ 106 _thread_run->poll_data.fds = data.fds; 107 _thread_run->poll_data.nfds = MAX(128, fd_count); 108 } 109 } 110 if (ret == 0) { 111 /* Setup the wait data. */ 112 data.fds = _thread_run->poll_data.fds; 113 data.nfds = fd_count; 114 115 /* 116 * Setup the array of pollfds. Optimize this by 117 * running the loop in reverse and stopping when 118 * the number of selected file descriptors is reached. 119 */ 120 for (i = numfds - 1, pfd_index = fd_count - 1; 121 (i >= 0) && (pfd_index >= 0); i--) { 122 data.fds[pfd_index].events = 0; 123 if (readfds && FD_ISSET(i, readfds)) { 124 data.fds[pfd_index].events = POLLRDNORM; 125 } 126 if (exceptfds && FD_ISSET(i, exceptfds)) { 127 data.fds[pfd_index].events |= POLLRDBAND; 128 } 129 if (writefds && FD_ISSET(i, writefds)) { 130 data.fds[pfd_index].events |= POLLWRNORM; 131 } 132 if (data.fds[pfd_index].events != 0) { 133 /* 134 * Set the file descriptor to be polled and 135 * clear revents in case of a timeout which 136 * leaves fds unchanged: 137 */ 138 data.fds[pfd_index].fd = i; 139 data.fds[pfd_index].revents = 0; 140 pfd_index--; 141 } 142 } 143 if (((ret = _thread_sys_poll(data.fds, data.nfds, 0)) == 0) && 144 (f_wait != 0)) { 145 _thread_run->data.poll_data = &data; 146 _thread_run->interrupted = 0; 147 _thread_kern_sched_state(PS_SELECT_WAIT, __FILE__, __LINE__); 148 if (_thread_run->interrupted) { 149 errno = EINTR; 150 data.nfds = 0; 151 ret = -1; 152 } else 153 ret = data.nfds; 154 } 155 } 156 157 if (ret >= 0) { 158 numfds = 0; 159 for (i = 0; i < fd_count; i++) { 160 /* 161 * Check the results of the poll and clear 162 * this file descriptor from the fdset if 163 * the requested event wasn't ready. 164 */ 165 got_one = 0; 166 if (readfds != NULL) { 167 if (FD_ISSET(data.fds[i].fd, readfds)) { 168 if (data.fds[i].revents & (POLLIN | 169 POLLRDNORM)) 170 got_one = 1; 171 else 172 FD_CLR(data.fds[i].fd, readfds); 173 } 174 } 175 if (writefds != NULL) { 176 if (FD_ISSET(data.fds[i].fd, writefds)) { 177 if (data.fds[i].revents & (POLLOUT | 178 POLLWRNORM | POLLWRBAND)) 179 got_one = 1; 180 else 181 FD_CLR(data.fds[i].fd, 182 writefds); 183 } 184 } 185 if (exceptfds != NULL) { 186 if (FD_ISSET(data.fds[i].fd, exceptfds)) { 187 if (data.fds[i].revents & (POLLRDBAND | 188 POLLPRI | POLLHUP | POLLERR | 189 POLLNVAL)) 190 got_one = 1; 191 else 192 FD_CLR(data.fds[i].fd, 193 exceptfds); 194 } 195 } 196 if (got_one) 197 numfds++; 198 } 199 ret = numfds; 200 } 201 202 return (ret); 203} 204#endif 205