thr_spec.c revision 132120 
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/libkse/thread/thr_spec.c 132120 2004-07-13 22:49:58Z davidxu $
33 */
34#include <signal.h>
35#include <stdlib.h>
36#include <string.h>
37#include <errno.h>
38#include <pthread.h>
39#include "thr_private.h"
40
41/* Static variables: */
42struct pthread_key _thread_keytable[PTHREAD_KEYS_MAX];
43
44__weak_reference(_pthread_key_create, pthread_key_create);
45__weak_reference(_pthread_key_delete, pthread_key_delete);
46__weak_reference(_pthread_getspecific, pthread_getspecific);
47__weak_reference(_pthread_setspecific, pthread_setspecific);
48
49
50int
51_pthread_key_create(pthread_key_t *key, void (*destructor) (void *))
52{
53	struct pthread *curthread = _get_curthread();
54	int i;
55
56	/* Lock the key table: */
57	THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
58	for (i = 0; i < PTHREAD_KEYS_MAX; i++) {
59
60		if (_thread_keytable[i].allocated == 0) {
61			_thread_keytable[i].allocated = 1;
62			_thread_keytable[i].destructor = destructor;
63			_thread_keytable[i].seqno++;
64
65			/* Unlock the key table: */
66			THR_LOCK_RELEASE(curthread, &_keytable_lock);
67			*key = i;
68			return (0);
69		}
70
71	}
72	/* Unlock the key table: */
73	THR_LOCK_RELEASE(curthread, &_keytable_lock);
74	return (EAGAIN);
75}
76
77int
78_pthread_key_delete(pthread_key_t key)
79{
80	struct pthread *curthread = _get_curthread();
81	int ret = 0;
82
83	if ((unsigned int)key < PTHREAD_KEYS_MAX) {
84		/* Lock the key table: */
85		THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
86
87		if (_thread_keytable[key].allocated)
88			_thread_keytable[key].allocated = 0;
89		else
90			ret = EINVAL;
91
92		/* Unlock the key table: */
93		THR_LOCK_RELEASE(curthread, &_keytable_lock);
94	} else
95		ret = EINVAL;
96	return (ret);
97}
98
99void
100_thread_cleanupspecific(void)
101{
102	struct pthread	*curthread = _get_curthread();
103	void		(*destructor)( void *);
104	void		*data = NULL;
105	int		key;
106	int		i;
107
108	if (curthread->specific == NULL)
109		return;
110
111	/* Lock the key table: */
112	THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
113	for (i = 0; (i < PTHREAD_DESTRUCTOR_ITERATIONS) &&
114	    (curthread->specific_data_count > 0); i++) {
115		for (key = 0; (key < PTHREAD_KEYS_MAX) &&
116		    (curthread->specific_data_count > 0); key++) {
117			destructor = NULL;
118
119			if (_thread_keytable[key].allocated &&
120			    (curthread->specific[key].data != NULL)) {
121				if (curthread->specific[key].seqno ==
122				    _thread_keytable[key].seqno) {
123					data = (void *)
124					    curthread->specific[key].data;
125					destructor = _thread_keytable[key].destructor;
126				}
127				curthread->specific[key].data = NULL;
128				curthread->specific_data_count--;
129			}
130
131			/*
132			 * If there is a destructore, call it
133			 * with the key table entry unlocked:
134			 */
135			if (destructor != NULL) {
136				/*
137				 * Don't hold the lock while calling the
138				 * destructor:
139				 */
140				THR_LOCK_RELEASE(curthread, &_keytable_lock);
141				destructor(data);
142				THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
143			}
144		}
145	}
146	THR_LOCK_RELEASE(curthread, &_keytable_lock);
147	free(curthread->specific);
148	curthread->specific = NULL;
149	if (curthread->specific_data_count > 0)
150		stderr_debug("Thread %p has exited with leftover "
151		    "thread-specific data after %d destructor iterations\n",
152		    curthread, PTHREAD_DESTRUCTOR_ITERATIONS);
153}
154
155static inline struct pthread_specific_elem *
156pthread_key_allocate_data(void)
157{
158	struct pthread_specific_elem *new_data;
159
160	new_data = (struct pthread_specific_elem *)
161	    malloc(sizeof(struct pthread_specific_elem) * PTHREAD_KEYS_MAX);
162	if (new_data != NULL) {
163		memset((void *) new_data, 0,
164		    sizeof(struct pthread_specific_elem) * PTHREAD_KEYS_MAX);
165	}
166	return (new_data);
167}
168
169int
170_pthread_setspecific(pthread_key_t key, const void *value)
171{
172	struct pthread	*pthread;
173	int		ret = 0;
174
175	/* Point to the running thread: */
176	pthread = _get_curthread();
177
178	if ((pthread->specific) ||
179	    (pthread->specific = pthread_key_allocate_data())) {
180		if ((unsigned int)key < PTHREAD_KEYS_MAX) {
181			if (_thread_keytable[key].allocated) {
182				if (pthread->specific[key].data == NULL) {
183					if (value != NULL)
184						pthread->specific_data_count++;
185				} else if (value == NULL)
186					pthread->specific_data_count--;
187				pthread->specific[key].data = value;
188				pthread->specific[key].seqno =
189				    _thread_keytable[key].seqno;
190				ret = 0;
191			} else
192				ret = EINVAL;
193		} else
194			ret = EINVAL;
195	} else
196		ret = ENOMEM;
197	return (ret);
198}
199
200void *
201_pthread_getspecific(pthread_key_t key)
202{
203	struct pthread	*pthread;
204	void		*data;
205
206	/* Point to the running thread: */
207	pthread = _get_curthread();
208
209	/* Check if there is specific data: */
210	if (pthread->specific != NULL && (unsigned int)key < PTHREAD_KEYS_MAX) {
211		/* Check if this key has been used before: */
212		if (_thread_keytable[key].allocated &&
213		    (pthread->specific[key].seqno == _thread_keytable[key].seqno)) {
214			/* Return the value: */
215			data = (void *) pthread->specific[key].data;
216		} else {
217			/*
218			 * This key has not been used before, so return NULL
219			 * instead:
220			 */
221			data = NULL;
222		}
223	} else
224		/* No specific data has been created, so just return NULL: */
225		data = NULL;
226	return (data);
227}
228