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. 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 <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 /* Static variables: */
  43 struct pthread_key _thread_keytable[PTHREAD_KEYS_MAX];
  44
  45 __weak_reference(_pthread_key_create, pthread_key_create);
  46 __weak_reference(_pthread_key_delete, pthread_key_delete);
  47 __weak_reference(_pthread_getspecific, pthread_getspecific);
  48 __weak_reference(_pthread_setspecific, pthread_setspecific);
  49
  50
  51 int
  52 _pthread_key_create(pthread_key_t *key, void (*destructor) (void *))
  53 {
  54         struct pthread *curthread;
  55         int i;
  56
  57         _thr_check_init();
  58
  59         curthread = _get_curthread();
  60
  61         /* Lock the key table: */
  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                         /* Unlock the key table: */
  71                         THR_LOCK_RELEASE(curthread, &_keytable_lock);
  72                         *key = i;
  73                         return (0);
  74                 }
  75
  76         }
  77         /* Unlock the key table: */
  78         THR_LOCK_RELEASE(curthread, &_keytable_lock);
  79         return (EAGAIN);
  80 }
  81
  82 int
  83 _pthread_key_delete(pthread_key_t key)
  84 {
  85         struct pthread *curthread = _get_curthread();
  86         int ret = 0;
  87
  88         if ((unsigned int)key < PTHREAD_KEYS_MAX) {
  89                 /* Lock the key table: */
  90                 THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
  91
  92                 if (_thread_keytable[key].allocated)
  93                         _thread_keytable[key].allocated = 0;
  94                 else
  95                         ret = EINVAL;
  96
  97                 /* Unlock the key table: */
  98                 THR_LOCK_RELEASE(curthread, &_keytable_lock);
  99         } else
 100                 ret = EINVAL;
 101         return (ret);
 102 }
 103
 104 void
 105 _thread_cleanupspecific(void)
 106 {
 107         struct pthread  *curthread = _get_curthread();
 108         void            (*destructor)( void *);
 109         const void      *data = NULL;
 110         int             key;
 111         int             i;
 112
 113         if (curthread->specific == NULL)
 114                 return;
 115
 116         /* Lock the key table: */
 117         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 118         for (i = 0; (i < PTHREAD_DESTRUCTOR_ITERATIONS) &&
 119             (curthread->specific_data_count > 0); i++) {
 120                 for (key = 0; (key < PTHREAD_KEYS_MAX) &&
 121                     (curthread->specific_data_count > 0); key++) {
 122                         destructor = NULL;
 123
 124                         if (_thread_keytable[key].allocated &&
 125                             (curthread->specific[key].data != NULL)) {
 126                                 if (curthread->specific[key].seqno ==
 127                                     _thread_keytable[key].seqno) {
 128                                         data = curthread->specific[key].data;
 129                                         destructor = _thread_keytable[key].destructor;
 130                                 }
 131                                 curthread->specific[key].data = NULL;
 132                                 curthread->specific_data_count--;
 133                         }
 134                         else if (curthread->specific[key].data != NULL) {
 135                                 /*
 136                                  * This can happen if the key is deleted via
 137                                  * pthread_key_delete without first setting the value
 138                                  * to NULL in all threads.  POSIX says that the
 139                                  * destructor is not invoked in this case.
 140                                  */
 141                                 curthread->specific[key].data = NULL;
 142                                 curthread->specific_data_count--;
 143                         }
 144
 145                         /*
 146                          * If there is a destructor, call it
 147                          * with the key table entry unlocked:
 148                          */
 149                         if (destructor != NULL) {
 150                                 /*
 151                                  * Don't hold the lock while calling the
 152                                  * destructor:
 153                                  */
 154                                 THR_LOCK_RELEASE(curthread, &_keytable_lock);
 155                                 destructor(__DECONST(void *, data));
 156                                 THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 157                         }
 158                 }
 159         }
 160         THR_LOCK_RELEASE(curthread, &_keytable_lock);
 161         free(curthread->specific);
 162         curthread->specific = NULL;
 163         if (curthread->specific_data_count > 0)
 164                 stderr_debug("Thread %p has exited with leftover "
 165                     "thread-specific data after %d destructor iterations\n",
 166                     curthread, PTHREAD_DESTRUCTOR_ITERATIONS);
 167 }
 168
 169 static inline struct pthread_specific_elem *
 170 pthread_key_allocate_data(void)
 171 {
 172         struct pthread_specific_elem *new_data;
 173
 174         new_data = (struct pthread_specific_elem *)
 175             calloc(1, sizeof(struct pthread_specific_elem) * PTHREAD_KEYS_MAX);
 176         return (new_data);
 177 }
 178
 179 int
 180 _pthread_setspecific(pthread_key_t key, const void *value)
 181 {
 182         struct pthread  *pthread;
 183         int             ret = 0;
 184
 185         /* Point to the running thread: */
 186         pthread = _get_curthread();
 187
 188         if ((pthread->specific) ||
 189             (pthread->specific = pthread_key_allocate_data())) {
 190                 if ((unsigned int)key < PTHREAD_KEYS_MAX) {
 191                         if (_thread_keytable[key].allocated) {
 192                                 if (pthread->specific[key].data == NULL) {
 193                                         if (value != NULL)
 194                                                 pthread->specific_data_count++;
 195                                 } else if (value == NULL)
 196                                         pthread->specific_data_count--;
 197                                 pthread->specific[key].data = value;
 198                                 pthread->specific[key].seqno =
 199                                     _thread_keytable[key].seqno;
 200                                 ret = 0;
 201                         } else
 202                                 ret = EINVAL;
 203                 } else
 204                         ret = EINVAL;
 205         } else
 206                 ret = ENOMEM;
 207         return (ret);
 208 }
 209
 210 void *
 211 _pthread_getspecific(pthread_key_t key)
 212 {
 213         struct pthread  *pthread;
 214         const void      *data;
 215
 216         /* Point to the running thread: */
 217         pthread = _get_curthread();
 218
 219         /* Check if there is specific data: */
 220         if (pthread->specific != NULL && (unsigned int)key < PTHREAD_KEYS_MAX) {
 221                 /* Check if this key has been used before: */
 222                 if (_thread_keytable[key].allocated &&
 223                     (pthread->specific[key].seqno == _thread_keytable[key].seqno)) {
 224                         /* Return the value: */
 225                         data = pthread->specific[key].data;
 226                 } else {
 227                         /*
 228                          * This key has not been used before, so return NULL
 229                          * instead:
 230                          */
 231                         data = NULL;
 232                 }
 233         } else
 234                 /* No specific data has been created, so just return NULL: */
 235                 data = NULL;
 236         return (__DECONST(void *, data));
 237 }