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 #include "libc_private.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         const 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 = curthread->specific[key].data;
 130                                         destructor = _thread_keytable[key].destructor;
 131                                 }
 132                                 curthread->specific[key].data = NULL;
 133                                 curthread->specific_data_count--;
 134                         }
 135                         else if (curthread->specific[key].data != NULL) {
 136                                 /*
 137                                  * This can happen if the key is deleted via
 138                                  * pthread_key_delete without first setting the value
 139                                  * to NULL in all threads.  POSIX says that the
 140                                  * destructor is not invoked in this case.
 141                                  */
 142                                 curthread->specific[key].data = NULL;
 143                                 curthread->specific_data_count--;
 144                         }
 145
 146                         /*
 147                          * If there is a destructor, call it
 148                          * with the key table entry unlocked:
 149                          */
 150                         if (destructor != NULL) {
 151                                 /*
 152                                  * Don't hold the lock while calling the
 153                                  * destructor:
 154                                  */
 155                                 THR_LOCK_RELEASE(curthread, &_keytable_lock);
 156                                 destructor(__DECONST(void *, data));
 157                                 THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 158                         }
 159                 }
 160         }
 161         THR_LOCK_RELEASE(curthread, &_keytable_lock);
 162         free(curthread->specific);
 163         curthread->specific = NULL;
 164         if (curthread->specific_data_count > 0)
 165                 stderr_debug("Thread %p has exited with leftover "
 166                     "thread-specific data after %d destructor iterations\n",
 167                     curthread, PTHREAD_DESTRUCTOR_ITERATIONS);
 168 }
 169
 170 static inline struct pthread_specific_elem *
 171 pthread_key_allocate_data(void)
 172 {
 173         struct pthread_specific_elem *new_data;
 174
 175         new_data = (struct pthread_specific_elem *)
 176             calloc(1, sizeof(struct pthread_specific_elem) * PTHREAD_KEYS_MAX);
 177         return (new_data);
 178 }
 179
 180 int
 181 _pthread_setspecific(pthread_key_t key, const void *value)
 182 {
 183         struct pthread  *pthread;
 184         int             ret = 0;
 185
 186         /* Point to the running thread: */
 187         pthread = _get_curthread();
 188
 189         if ((pthread->specific) ||
 190             (pthread->specific = pthread_key_allocate_data())) {
 191                 if ((unsigned int)key < PTHREAD_KEYS_MAX) {
 192                         if (_thread_keytable[key].allocated) {
 193                                 if (pthread->specific[key].data == NULL) {
 194                                         if (value != NULL)
 195                                                 pthread->specific_data_count++;
 196                                 } else if (value == NULL)
 197                                         pthread->specific_data_count--;
 198                                 pthread->specific[key].data = value;
 199                                 pthread->specific[key].seqno =
 200                                     _thread_keytable[key].seqno;
 201                                 ret = 0;
 202                         } else
 203                                 ret = EINVAL;
 204                 } else
 205                         ret = EINVAL;
 206         } else
 207                 ret = ENOMEM;
 208         return (ret);
 209 }
 210
 211 void *
 212 _pthread_getspecific(pthread_key_t key)
 213 {
 214         struct pthread  *pthread;
 215         const void      *data;
 216
 217         /* Point to the running thread: */
 218         pthread = _get_curthread();
 219
 220         /* Check if there is specific data: */
 221         if (pthread->specific != NULL && (unsigned int)key < PTHREAD_KEYS_MAX) {
 222                 /* Check if this key has been used before: */
 223                 if (_thread_keytable[key].allocated &&
 224                     (pthread->specific[key].seqno == _thread_keytable[key].seqno)) {
 225                         /* Return the value: */
 226                         data = pthread->specific[key].data;
 227                 } else {
 228                         /*
 229                          * This key has not been used before, so return NULL
 230                          * instead:
 231                          */
 232                         data = NULL;
 233                 }
 234         } else
 235                 /* No specific data has been created, so just return NULL: */
 236                 data = NULL;
 237         return (__DECONST(void *, data));
 238 }
 239
 240 void
 241 _thr_tsd_unload(struct dl_phdr_info *phdr_info)
 242 {
 243         struct pthread *curthread = _get_curthread();
 244         void (*destructor)(void *);
 245         int key;
 246
 247         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 248         for (key = 0; key < PTHREAD_KEYS_MAX; key++) {
 249                 if (_thread_keytable[key].allocated) {
 250                         destructor = _thread_keytable[key].destructor;
 251                         if (destructor != NULL) {
 252                                 if (__elf_phdr_match_addr(phdr_info, destructor))
 253                                         _thread_keytable[key].destructor = NULL;
 254                         }
 255                 }
 256         }
 257         THR_LOCK_RELEASE(curthread, &_keytable_lock);
 258 }