thr_select.c revision 35509 
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 */
33#include <unistd.h>
34#include <errno.h>
35#include <string.h>
36#include <sys/types.h>
37#include <sys/time.h>
38#ifdef _THREAD_SAFE
39#include <pthread.h>
40#include "pthread_private.h"
41
42int
43select(int numfds, fd_set * readfds, fd_set * writefds,
44       fd_set * exceptfds, struct timeval * timeout)
45{
46	fd_set          read_locks, write_locks, rdwr_locks;
47	struct timespec ts;
48	struct timeval  zero_timeout = {0, 0};
49	int             i, ret = 0, got_all_locks = 1;
50	struct pthread_select_data data;
51
52	if (numfds > _thread_dtablesize) {
53		numfds = _thread_dtablesize;
54	}
55	/* Check if a timeout was specified: */
56	if (timeout) {
57		/* Convert the timeval to a timespec: */
58		TIMEVAL_TO_TIMESPEC(timeout, &ts);
59
60		/* Set the wake up time: */
61		_thread_kern_set_timeout(&ts);
62	} else {
63		/* Wait for ever: */
64		_thread_kern_set_timeout(NULL);
65	}
66
67	FD_ZERO(&read_locks);
68	FD_ZERO(&write_locks);
69	FD_ZERO(&rdwr_locks);
70
71	/* lock readfds */
72	if (readfds || writefds || exceptfds) {
73		for (i = 0; i < numfds; i++) {
74			if ((readfds && (FD_ISSET(i, readfds))) || (exceptfds && FD_ISSET(i, exceptfds))) {
75				if (writefds && FD_ISSET(i, writefds)) {
76					if ((ret = _thread_fd_lock(i, FD_RDWR, NULL, __FILE__, __LINE__)) != 0) {
77						got_all_locks = 0;
78						break;
79					}
80					FD_SET(i, &rdwr_locks);
81				} else {
82					if ((ret = _thread_fd_lock(i, FD_READ, NULL, __FILE__, __LINE__)) != 0) {
83						got_all_locks = 0;
84						break;
85					}
86					FD_SET(i, &read_locks);
87				}
88			} else {
89				if (writefds && FD_ISSET(i, writefds)) {
90					if ((ret = _thread_fd_lock(i, FD_WRITE, NULL, __FILE__, __LINE__)) != 0) {
91						got_all_locks = 0;
92						break;
93					}
94					FD_SET(i, &write_locks);
95				}
96			}
97		}
98	}
99	if (got_all_locks) {
100		data.nfds = numfds;
101		FD_ZERO(&data.readfds);
102		FD_ZERO(&data.writefds);
103		FD_ZERO(&data.exceptfds);
104		if (readfds != NULL) {
105			memcpy(&data.readfds, readfds, sizeof(data.readfds));
106		}
107		if (writefds != NULL) {
108			memcpy(&data.writefds, writefds, sizeof(data.writefds));
109		}
110		if (exceptfds != NULL) {
111			memcpy(&data.exceptfds, exceptfds, sizeof(data.exceptfds));
112		}
113		if ((ret = _thread_sys_select(data.nfds, &data.readfds, &data.writefds, &data.exceptfds, &zero_timeout)) == 0) {
114			data.nfds = numfds;
115			FD_ZERO(&data.readfds);
116			FD_ZERO(&data.writefds);
117			FD_ZERO(&data.exceptfds);
118			if (readfds != NULL) {
119				memcpy(&data.readfds, readfds, sizeof(data.readfds));
120			}
121			if (writefds != NULL) {
122				memcpy(&data.writefds, writefds, sizeof(data.writefds));
123			}
124			if (exceptfds != NULL) {
125				memcpy(&data.exceptfds, exceptfds, sizeof(data.exceptfds));
126			}
127			_thread_run->data.select_data = &data;
128			_thread_run->interrupted = 0;
129			_thread_kern_sched_state(PS_SELECT_WAIT, __FILE__, __LINE__);
130			if (_thread_run->interrupted) {
131				errno = EINTR;
132				ret = -1;
133			} else
134				ret = data.nfds;
135		}
136	}
137	/* clean up the locks */
138	for (i = 0; i < numfds; i++)
139		if (FD_ISSET(i, &read_locks))
140			_thread_fd_unlock(i, FD_READ);
141	for (i = 0; i < numfds; i++)
142		if (FD_ISSET(i, &rdwr_locks))
143			_thread_fd_unlock(i, FD_RDWR);
144	for (i = 0; i < numfds; i++)
145		if (FD_ISSET(i, &write_locks))
146			_thread_fd_unlock(i, FD_WRITE);
147
148	if (ret > 0) {
149		if (readfds != NULL) {
150			for (i = 0; i < numfds; i++) {
151				if (FD_ISSET(i, readfds) &&
152					!FD_ISSET(i, &data.readfds)) {
153					FD_CLR(i, readfds);
154				}
155			}
156		}
157		if (writefds != NULL) {
158			for (i = 0; i < numfds; i++) {
159				if (FD_ISSET(i, writefds) &&
160					!FD_ISSET(i, &data.writefds)) {
161					FD_CLR(i, writefds);
162				}
163			}
164		}
165		if (exceptfds != NULL) {
166			for (i = 0; i < numfds; i++) {
167				if (FD_ISSET(i, exceptfds) &&
168					!FD_ISSET(i, &data.exceptfds)) {
169					FD_CLR(i, exceptfds);
170				}
171			}
172		}
173	}
174
175	return (ret);
176}
177#endif
178