thr_spec.c revision 157457 
1/*
2 * Copyright (c) 1995 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/libthr/thread/thr_spec.c 157457 2006-04-04 02:57:49Z davidxu $
33 */
34
35#include "namespace.h"
36#include <signal.h>
37#include <stdlib.h>
38#include <string.h>
39#include <errno.h>
40#include <pthread.h>
41#include "un-namespace.h"
42
43#include "thr_private.h"
44
45/* Static variables: */
46struct pthread_key _thread_keytable[PTHREAD_KEYS_MAX];
47
48__weak_reference(_pthread_key_create, pthread_key_create);
49__weak_reference(_pthread_key_delete, pthread_key_delete);
50__weak_reference(_pthread_getspecific, pthread_getspecific);
51__weak_reference(_pthread_setspecific, pthread_setspecific);
52
53
54int
55_pthread_key_create(pthread_key_t *key, void (*destructor) (void *))
56{
57	struct pthread *curthread = _get_curthread();
58	int i;
59
60	/* Lock the key table: */
61	THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
62	for (i = 0; i < PTHREAD_KEYS_MAX; i++) {
63
64		if (_thread_keytable[i].allocated == 0) {
65			_thread_keytable[i].allocated = 1;
66			_thread_keytable[i].destructor = destructor;
67			_thread_keytable[i].seqno++;
68
69			/* Unlock the key table: */
70			THR_LOCK_RELEASE(curthread, &_keytable_lock);
71			*key = i;
72			return (0);
73		}
74
75	}
76	/* Unlock the key table: */
77	THR_LOCK_RELEASE(curthread, &_keytable_lock);
78	return (EAGAIN);
79}
80
81int
82_pthread_key_delete(pthread_key_t key)
83{
84	struct pthread *curthread = _get_curthread();
85	int ret = 0;
86
87	if ((unsigned int)key < PTHREAD_KEYS_MAX) {
88		/* Lock the key table: */
89		THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
90
91		if (_thread_keytable[key].allocated)
92			_thread_keytable[key].allocated = 0;
93		else
94			ret = EINVAL;
95
96		/* Unlock the key table: */
97		THR_LOCK_RELEASE(curthread, &_keytable_lock);
98	} else
99		ret = EINVAL;
100	return (ret);
101}
102
103void
104_thread_cleanupspecific(void)
105{
106	struct pthread	*curthread = _get_curthread();
107	void		(*destructor)( void *);
108	const void	*data = NULL;
109	int		key;
110	int		i;
111
112	if (curthread->specific == NULL)
113		return;
114
115	/* Lock the key table: */
116	THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
117	for (i = 0; (i < PTHREAD_DESTRUCTOR_ITERATIONS) &&
118	    (curthread->specific_data_count > 0); i++) {
119		for (key = 0; (key < PTHREAD_KEYS_MAX) &&
120		    (curthread->specific_data_count > 0); key++) {
121			destructor = NULL;
122
123			if (_thread_keytable[key].allocated &&
124			    (curthread->specific[key].data != NULL)) {
125				if (curthread->specific[key].seqno ==
126				    _thread_keytable[key].seqno) {
127					data = curthread->specific[key].data;
128					destructor = _thread_keytable[key].destructor;
129				}
130				curthread->specific[key].data = NULL;
131				curthread->specific_data_count--;
132			}
133
134			/*
135			 * If there is a destructore, call it
136			 * with the key table entry unlocked:
137			 */
138			if (destructor != NULL) {
139				/*
140				 * Don't hold the lock while calling the
141				 * destructor:
142				 */
143				THR_LOCK_RELEASE(curthread, &_keytable_lock);
144				destructor(__DECONST(void *, data));
145				THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
146			}
147		}
148	}
149	THR_LOCK_RELEASE(curthread, &_keytable_lock);
150	free(curthread->specific);
151	curthread->specific = NULL;
152	if (curthread->specific_data_count > 0)
153		stderr_debug("Thread %p has exited with leftover "
154		    "thread-specific data after %d destructor iterations\n",
155		    curthread, PTHREAD_DESTRUCTOR_ITERATIONS);
156}
157
158static inline struct pthread_specific_elem *
159pthread_key_allocate_data(void)
160{
161	struct pthread_specific_elem *new_data;
162
163	new_data = (struct pthread_specific_elem *)
164	    malloc(sizeof(struct pthread_specific_elem) * PTHREAD_KEYS_MAX);
165	if (new_data != NULL) {
166		memset((void *) new_data, 0,
167		    sizeof(struct pthread_specific_elem) * PTHREAD_KEYS_MAX);
168	}
169	return (new_data);
170}
171
172int
173_pthread_setspecific(pthread_key_t key, const void *value)
174{
175	struct pthread	*pthread;
176	int		ret = 0;
177
178	/* Point to the running thread: */
179	pthread = _get_curthread();
180
181	if ((pthread->specific) ||
182	    (pthread->specific = pthread_key_allocate_data())) {
183		if ((unsigned int)key < PTHREAD_KEYS_MAX) {
184			if (_thread_keytable[key].allocated) {
185				if (pthread->specific[key].data == NULL) {
186					if (value != NULL)
187						pthread->specific_data_count++;
188				} else if (value == NULL)
189					pthread->specific_data_count--;
190				pthread->specific[key].data = value;
191				pthread->specific[key].seqno =
192				    _thread_keytable[key].seqno;
193				ret = 0;
194			} else
195				ret = EINVAL;
196		} else
197			ret = EINVAL;
198	} else
199		ret = ENOMEM;
200	return (ret);
201}
202
203void *
204_pthread_getspecific(pthread_key_t key)
205{
206	struct pthread	*pthread;
207	const void	*data;
208
209	/* Point to the running thread: */
210	pthread = _get_curthread();
211
212	/* Check if there is specific data: */
213	if (pthread->specific != NULL && (unsigned int)key < PTHREAD_KEYS_MAX) {
214		/* Check if this key has been used before: */
215		if (_thread_keytable[key].allocated &&
216		    (pthread->specific[key].seqno == _thread_keytable[key].seqno)) {
217			/* Return the value: */
218			data = pthread->specific[key].data;
219		} else {
220			/*
221			 * This key has not been used before, so return NULL
222			 * instead:
223			 */
224			data = NULL;
225		}
226	} else
227		/* No specific data has been created, so just return NULL: */
228		data = NULL;
229	return (__DECONST(void *, data));
230}
231