6/lib/libthr/thread/thr_spec.c

   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  * $FreeBSD$
  33  */
  34
  35 #include <signal.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <errno.h>
  39 #include <pthread.h>
  40
  41 #include "thr_private.h"
  42
  43 /* Static variables: */
  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         /* Lock the key table: */
  63         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
  64         for (i = 0; i < PTHREAD_KEYS_MAX; i++) {
  65
  66                 if (_thread_keytable[i].allocated == 0) {
  67                         _thread_keytable[i].allocated = 1;
  68                         _thread_keytable[i].destructor = destructor;
  69                         _thread_keytable[i].seqno++;
  70
  71                         /* Unlock the key table: */
  72                         THR_LOCK_RELEASE(curthread, &_keytable_lock);
  73                         *key = i;
  74                         return (0);
  75                 }
  76
  77         }
  78         /* Unlock the key table: */
  79         THR_LOCK_RELEASE(curthread, &_keytable_lock);
  80         return (EAGAIN);
  81 }
  82
  83 int
  84 _pthread_key_delete(pthread_key_t key)
  85 {
  86         struct pthread *curthread = _get_curthread();
  87         int ret = 0;
  88
  89         if ((unsigned int)key < PTHREAD_KEYS_MAX) {
  90                 /* Lock the key table: */
  91                 THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
  92
  93                 if (_thread_keytable[key].allocated)
  94                         _thread_keytable[key].allocated = 0;
  95                 else
  96                         ret = EINVAL;
  97
  98                 /* Unlock the key table: */
  99                 THR_LOCK_RELEASE(curthread, &_keytable_lock);
 100         } else
 101                 ret = EINVAL;
 102         return (ret);
 103 }
 104
 105 void
 106 _thread_cleanupspecific(void)
 107 {
 108         struct pthread  *curthread = _get_curthread();
 109         void            (*destructor)( void *);
 110         void            *data = NULL;
 111         int             key;
 112         int             i;
 113
 114         if (curthread->specific == NULL)
 115                 return;
 116
 117         /* Lock the key table: */
 118         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 119         for (i = 0; (i < PTHREAD_DESTRUCTOR_ITERATIONS) &&
 120             (curthread->specific_data_count > 0); i++) {
 121                 for (key = 0; (key < PTHREAD_KEYS_MAX) &&
 122                     (curthread->specific_data_count > 0); key++) {
 123                         destructor = NULL;
 124
 125                         if (_thread_keytable[key].allocated &&
 126                             (curthread->specific[key].data != NULL)) {
 127                                 if (curthread->specific[key].seqno ==
 128                                     _thread_keytable[key].seqno) {
 129                                         data = (void *)
 130                                             curthread->specific[key].data;
 131                                         destructor = _thread_keytable[key].destructor;
 132                                 }
 133                                 curthread->specific[key].data = NULL;
 134                                 curthread->specific_data_count--;
 135                         }
 136
 137                         /*
 138                          * If there is a destructore, call it
 139                          * with the key table entry unlocked:
 140                          */
 141                         if (destructor != NULL) {
 142                                 /*
 143                                  * Don't hold the lock while calling the
 144                                  * destructor:
 145                                  */
 146                                 THR_LOCK_RELEASE(curthread, &_keytable_lock);
 147                                 destructor(data);
 148                                 THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 149                         }
 150                 }
 151         }
 152         THR_LOCK_RELEASE(curthread, &_keytable_lock);
 153         free(curthread->specific);
 154         curthread->specific = NULL;
 155         if (curthread->specific_data_count > 0)
 156                 stderr_debug("Thread %p has exited with leftover "
 157                     "thread-specific data after %d destructor iterations\n",
 158                     curthread, PTHREAD_DESTRUCTOR_ITERATIONS);
 159 }
 160
 161 static inline struct pthread_specific_elem *
 162 pthread_key_allocate_data(void)
 163 {
 164         struct pthread_specific_elem *new_data;
 165
 166         new_data = (struct pthread_specific_elem *)
 167             malloc(sizeof(struct pthread_specific_elem) * PTHREAD_KEYS_MAX);
 168         if (new_data != NULL) {
 169                 memset((void *) new_data, 0,
 170                     sizeof(struct pthread_specific_elem) * PTHREAD_KEYS_MAX);
 171         }
 172         return (new_data);
 173 }
 174
 175 int
 176 _pthread_setspecific(pthread_key_t key, const void *value)
 177 {
 178         struct pthread  *pthread;
 179         int             ret = 0;
 180
 181         /* Point to the running thread: */
 182         pthread = _get_curthread();
 183
 184         if ((pthread->specific) ||
 185             (pthread->specific = pthread_key_allocate_data())) {
 186                 if ((unsigned int)key < PTHREAD_KEYS_MAX) {
 187                         if (_thread_keytable[key].allocated) {
 188                                 if (pthread->specific[key].data == NULL) {
 189                                         if (value != NULL)
 190                                                 pthread->specific_data_count++;
 191                                 } else if (value == NULL)
 192                                         pthread->specific_data_count--;
 193                                 pthread->specific[key].data = value;
 194                                 pthread->specific[key].seqno =
 195                                     _thread_keytable[key].seqno;
 196                                 ret = 0;
 197                         } else
 198                                 ret = EINVAL;
 199                 } else
 200                         ret = EINVAL;
 201         } else
 202                 ret = ENOMEM;
 203         return (ret);
 204 }
 205
 206 void *
 207 _pthread_getspecific(pthread_key_t key)
 208 {
 209         struct pthread  *pthread;
 210         void            *data;
 211
 212         /* Point to the running thread: */
 213         pthread = _get_curthread();
 214
 215         /* Check if there is specific data: */
 216         if (pthread->specific != NULL && (unsigned int)key < PTHREAD_KEYS_MAX) {
 217                 /* Check if this key has been used before: */
 218                 if (_thread_keytable[key].allocated &&
 219                     (pthread->specific[key].seqno == _thread_keytable[key].seqno)) {
 220                         /* Return the value: */
 221                         data = (void *) pthread->specific[key].data;
 222                 } else {
 223                         /*
 224                          * This key has not been used before, so return NULL
 225                          * instead:
 226                          */
 227                         data = NULL;
 228                 }
 229         } else
 230                 /* No specific data has been created, so just return NULL: */
 231                 data = NULL;
 232         return (data);
 233 }