xref: /freebsd/lib/libthr/thread/thr_spec.c (revision f4b37ed0f8b307b1f3f0f630ca725d68f1dff30d)
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. Neither the name of the author nor the names of any co-contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * $FreeBSD$
30  */
31 
32 #include "namespace.h"
33 #include <sys/mman.h>
34 #include <signal.h>
35 #include <stdlib.h>
36 #include <string.h>
37 #include <errno.h>
38 #include <pthread.h>
39 #include "un-namespace.h"
40 #include "libc_private.h"
41 
42 #include "thr_private.h"
43 
44 struct pthread_key _thread_keytable[PTHREAD_KEYS_MAX];
45 
46 __weak_reference(_pthread_key_create, pthread_key_create);
47 __weak_reference(_pthread_key_delete, pthread_key_delete);
48 __weak_reference(_pthread_getspecific, pthread_getspecific);
49 __weak_reference(_pthread_setspecific, pthread_setspecific);
50 
51 
52 int
53 _pthread_key_create(pthread_key_t *key, void (*destructor)(void *))
54 {
55 	struct pthread *curthread;
56 	int i;
57 
58 	_thr_check_init();
59 
60 	curthread = _get_curthread();
61 
62 	THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
63 	for (i = 0; i < PTHREAD_KEYS_MAX; i++) {
64 
65 		if (_thread_keytable[i].allocated == 0) {
66 			_thread_keytable[i].allocated = 1;
67 			_thread_keytable[i].destructor = destructor;
68 			_thread_keytable[i].seqno++;
69 
70 			THR_LOCK_RELEASE(curthread, &_keytable_lock);
71 			*key = i + 1;
72 			return (0);
73 		}
74 
75 	}
76 	THR_LOCK_RELEASE(curthread, &_keytable_lock);
77 	return (EAGAIN);
78 }
79 
80 int
81 _pthread_key_delete(pthread_key_t userkey)
82 {
83 	struct pthread *curthread;
84 	int key, ret;
85 
86 	key = userkey - 1;
87 	if ((unsigned int)key >= PTHREAD_KEYS_MAX)
88 		return (EINVAL);
89 	curthread = _get_curthread();
90 	THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
91 	if (_thread_keytable[key].allocated) {
92 		_thread_keytable[key].allocated = 0;
93 		ret = 0;
94 	} else {
95 		ret = EINVAL;
96 	}
97 	THR_LOCK_RELEASE(curthread, &_keytable_lock);
98 	return (ret);
99 }
100 
101 void
102 _thread_cleanupspecific(void)
103 {
104 	struct pthread *curthread;
105 	void (*destructor)(void *);
106 	const void *data;
107 	int i, key;
108 
109 	curthread = _get_curthread();
110 	if (curthread->specific == NULL)
111 		return;
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 = curthread->specific[key].data;
124 					destructor = _thread_keytable[key].
125 					    destructor;
126 				}
127 				curthread->specific[key].data = NULL;
128 				curthread->specific_data_count--;
129 			} else if (curthread->specific[key].data != NULL) {
130 				/*
131 				 * This can happen if the key is
132 				 * deleted via pthread_key_delete
133 				 * without first setting the value to
134 				 * NULL in all threads.  POSIX says
135 				 * that the destructor is not invoked
136 				 * in this case.
137 				 */
138 				curthread->specific[key].data = NULL;
139 				curthread->specific_data_count--;
140 			}
141 
142 			/*
143 			 * If there is a destructor, call it with the
144 			 * key table entry unlocked.
145 			 */
146 			if (destructor != NULL) {
147 				THR_LOCK_RELEASE(curthread, &_keytable_lock);
148 				destructor(__DECONST(void *, data));
149 				THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
150 			}
151 		}
152 	}
153 	THR_LOCK_RELEASE(curthread, &_keytable_lock);
154 	munmap(curthread->specific, PTHREAD_KEYS_MAX * sizeof(struct
155 	    pthread_specific_elem));
156 	curthread->specific = NULL;
157 	if (curthread->specific_data_count > 0) {
158 		stderr_debug("Thread %p has exited with leftover "
159 		    "thread-specific data after %d destructor iterations\n",
160 		    curthread, PTHREAD_DESTRUCTOR_ITERATIONS);
161 	}
162 }
163 
164 int
165 _pthread_setspecific(pthread_key_t userkey, const void *value)
166 {
167 	struct pthread *pthread;
168 	void *tmp;
169 	pthread_key_t key;
170 
171 	key = userkey - 1;
172 	if ((unsigned int)key >= PTHREAD_KEYS_MAX ||
173 	    !_thread_keytable[key].allocated)
174 		return (EINVAL);
175 
176 	pthread = _get_curthread();
177 	if (pthread->specific == NULL) {
178 		tmp = mmap(NULL, PTHREAD_KEYS_MAX *
179 		    sizeof(struct pthread_specific_elem),
180 		    PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
181 		if (tmp == MAP_FAILED)
182 			return (ENOMEM);
183 		pthread->specific = tmp;
184 	}
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 = _thread_keytable[key].seqno;
192 	return (0);
193 }
194 
195 void *
196 _pthread_getspecific(pthread_key_t userkey)
197 {
198 	struct pthread *pthread;
199 	const void *data;
200 	pthread_key_t key;
201 
202 	/* Check if there is specific data. */
203 	key = userkey - 1;
204 	if ((unsigned int)key >= PTHREAD_KEYS_MAX)
205 		return (NULL);
206 
207 	pthread = _get_curthread();
208 	/* Check if this key has been used before. */
209 	if (_thread_keytable[key].allocated && pthread->specific != NULL &&
210 	    pthread->specific[key].seqno == _thread_keytable[key].seqno) {
211 		/* Return the value: */
212 		data = pthread->specific[key].data;
213 	} else {
214 		/*
215 		 * This key has not been used before, so return NULL
216 		 * instead.
217 		 */
218 		data = NULL;
219 	}
220 	return (__DECONST(void *, data));
221 }
222 
223 void
224 _thr_tsd_unload(struct dl_phdr_info *phdr_info)
225 {
226 	struct pthread *curthread;
227 	void (*destructor)(void *);
228 	int key;
229 
230 	curthread = _get_curthread();
231 	THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
232 	for (key = 0; key < PTHREAD_KEYS_MAX; key++) {
233 		if (!_thread_keytable[key].allocated)
234 			continue;
235 		destructor = _thread_keytable[key].destructor;
236 		if (destructor == NULL)
237 			continue;
238 		if (__elf_phdr_match_addr(phdr_info, destructor))
239 			_thread_keytable[key].destructor = NULL;
240 	}
241 	THR_LOCK_RELEASE(curthread, &_keytable_lock);
242 }
243