lib/libthread_xu/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. 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  */
  30
  31 #include "namespace.h"
  32 #include <machine/tls.h>
  33 #include <signal.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include <errno.h>
  37 #include <pthread.h>
  38 #include "un-namespace.h"
  39
  40 #include "thr_private.h"
  41
  42 struct pthread_key _thread_keytable[PTHREAD_KEYS_MAX];
  43 umtx_t  _keytable_lock;
  44
  45 int
  46 _pthread_key_create(pthread_key_t *key, void (*destructor) (void *))
  47 {
  48         struct pthread *curthread;
  49         int i;
  50
  51         /* User program might be preparing to call pthread_create() */
  52         _thr_check_init();
  53
  54         curthread = tls_get_curthread();
  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
  77 int
  78 _pthread_key_delete(pthread_key_t key)
  79 {
  80         struct pthread *curthread = tls_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
  99 void
 100 _thread_cleanupspecific(void)
 101 {
 102         struct pthread  *curthread = tls_get_curthread();
 103         void            (*destructor)( void *);
 104         const 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 = curthread->specific[key].data;
 124                                         destructor = _thread_keytable[key].destructor;
 125                                 }
 126                                 curthread->specific[key].data = NULL;
 127                                 curthread->specific_data_count--;
 128                         } else if (curthread->specific[key].data != NULL) {
 129                                 /*
 130                                  * This can happen if the key is deleted via
 131                                  * pthread_key_delete without first setting the value
 132                                  * to NULL in all threads. POSIX says that the
 133                                  * destructor is not invoked in this case.
 134                                  */
 135                                 curthread->specific[key].data = NULL;
 136                                 curthread->specific_data_count--;
 137                         }
 138
 139                         /*
 140                          * If there is a destructor, call it
 141                          * with the key table entry unlocked:
 142                          */
 143                         if (destructor != NULL) {
 144                                 /*
 145                                  * Don't hold the lock while calling the
 146                                  * destructor:
 147                                  */
 148                                 THR_LOCK_RELEASE(curthread, &_keytable_lock);
 149                                 destructor(__DECONST(void *, data));
 150                                 THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 151                         }
 152                 }
 153         }
 154         THR_LOCK_RELEASE(curthread, &_keytable_lock);
 155         free(curthread->specific);
 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 static inline struct pthread_specific_elem *
 164 pthread_key_allocate_data(void)
 165 {
 166         struct pthread_specific_elem *new_data;
 167
 168         new_data = (struct pthread_specific_elem *)
 169             malloc(sizeof(struct pthread_specific_elem) * PTHREAD_KEYS_MAX);
 170         if (new_data != NULL) {
 171                 memset((void *) new_data, 0,
 172                     sizeof(struct pthread_specific_elem) * PTHREAD_KEYS_MAX);
 173         }
 174         return (new_data);
 175 }
 176
 177 int
 178 _pthread_setspecific(pthread_key_t key, const void *value)
 179 {
 180         struct pthread  *pthread;
 181         int             ret = 0;
 182
 183         /* Point to the running thread: */
 184         pthread = tls_get_curthread();
 185
 186         if ((pthread->specific) ||
 187             (pthread->specific = pthread_key_allocate_data())) {
 188                 if ((unsigned int)key < PTHREAD_KEYS_MAX) {
 189                         if (_thread_keytable[key].allocated) {
 190                                 if (pthread->specific[key].data == NULL) {
 191                                         if (value != NULL)
 192                                                 pthread->specific_data_count++;
 193                                 } else if (value == NULL)
 194                                         pthread->specific_data_count--;
 195                                 pthread->specific[key].data = value;
 196                                 pthread->specific[key].seqno =
 197                                     _thread_keytable[key].seqno;
 198                                 ret = 0;
 199                         } else
 200                                 ret = EINVAL;
 201                 } else
 202                         ret = EINVAL;
 203         } else
 204                 ret = ENOMEM;
 205         return (ret);
 206 }
 207
 208 void *
 209 _pthread_getspecific(pthread_key_t key)
 210 {
 211         struct pthread  *pthread;
 212         const void      *data;
 213
 214         /* Point to the running thread: */
 215         pthread = tls_get_curthread();
 216
 217         /* Check if there is specific data: */
 218         if (pthread->specific != NULL && (unsigned int)key < PTHREAD_KEYS_MAX) {
 219                 /* Check if this key has been used before: */
 220                 if (_thread_keytable[key].allocated &&
 221                     (pthread->specific[key].seqno == _thread_keytable[key].seqno)) {
 222                         /* Return the value: */
 223                         data = pthread->specific[key].data;
 224                 } else {
 225                         /*
 226                          * This key has not been used before, so return NULL
 227                          * instead.
 228                          */
 229                         data = NULL;
 230                 }
 231         } else
 232                 /* No specific data has been created, so just return NULL: */
 233                 data = NULL;
 234         return __DECONST(void *, data);
 235 }
 236
 237 __strong_reference(_pthread_key_create, pthread_key_create);
 238 __strong_reference(_pthread_key_delete, pthread_key_delete);
 239 __strong_reference(_pthread_getspecific, pthread_getspecific);
 240 __strong_reference(_pthread_setspecific, pthread_setspecific);