thr_select.c revision 50065 
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 * $Id: uthread_select.c,v 1.9 1999/08/05 12:15:21 deischen 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#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 (timeout->tv_sec < 0 ||
57		timeout->tv_usec < 0 || timeout->tv_usec >= 1000000)
58		return (EINVAL);
59
60	if (numfds > _thread_dtablesize) {
61		numfds = _thread_dtablesize;
62	}
63	/* Check if a timeout was specified: */
64	if (timeout) {
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