lib/libthr/thread/thr_spec.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the author nor the names of any co-contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #include "namespace.h"
  34 #include <sys/mman.h>
  35 #include <signal.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <errno.h>
  39 #include <pthread.h>
  40 #include "un-namespace.h"
  41 #include "libc_private.h"
  42
  43 #include "thr_private.h"
  44
  45 /* Used in symbol lookup of libthread_db */
  46 struct pthread_key _thread_keytable[PTHREAD_KEYS_MAX];
  47
  48 __weak_reference(_thr_key_create, pthread_key_create);
  49 __weak_reference(_thr_key_create, _pthread_key_create);
  50 __weak_reference(_thr_key_delete, pthread_key_delete);
  51 __weak_reference(_thr_key_delete, _pthread_key_delete);
  52 __weak_reference(_thr_getspecific, pthread_getspecific);
  53 __weak_reference(_thr_getspecific, _pthread_getspecific);
  54 __weak_reference(_thr_setspecific, pthread_setspecific);
  55 __weak_reference(_thr_setspecific, _pthread_setspecific);
  56
  57 int
  58 _thr_key_create(pthread_key_t *key, void (*destructor)(void *))
  59 {
  60         struct pthread *curthread;
  61         int i;
  62
  63         _thr_check_init();
  64
  65         curthread = _get_curthread();
  66
  67         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
  68         for (i = 0; i < PTHREAD_KEYS_MAX; i++) {
  69
  70                 if (_thread_keytable[i].allocated == 0) {
  71                         _thread_keytable[i].allocated = 1;
  72                         _thread_keytable[i].destructor = destructor;
  73                         _thread_keytable[i].seqno++;
  74
  75                         THR_LOCK_RELEASE(curthread, &_keytable_lock);
  76                         *key = i + 1;
  77                         return (0);
  78                 }
  79
  80         }
  81         THR_LOCK_RELEASE(curthread, &_keytable_lock);
  82         return (EAGAIN);
  83 }
  84
  85 int
  86 _thr_key_delete(pthread_key_t userkey)
  87 {
  88         struct pthread *curthread;
  89         int key, ret;
  90
  91         key = userkey - 1;
  92         if ((unsigned int)key >= PTHREAD_KEYS_MAX)
  93                 return (EINVAL);
  94         curthread = _get_curthread();
  95         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
  96         if (_thread_keytable[key].allocated) {
  97                 _thread_keytable[key].allocated = 0;
  98                 ret = 0;
  99         } else {
 100                 ret = EINVAL;
 101         }
 102         THR_LOCK_RELEASE(curthread, &_keytable_lock);
 103         return (ret);
 104 }
 105
 106 void
 107 _thread_cleanupspecific(void)
 108 {
 109         struct pthread *curthread;
 110         void (*destructor)(void *);
 111         const void *data;
 112         int i, key;
 113
 114         curthread = _get_curthread();
 115         if (curthread->specific == NULL)
 116                 return;
 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].
 130                                             destructor;
 131                                 }
 132                                 curthread->specific[key].data = NULL;
 133                                 curthread->specific_data_count--;
 134                         } else if (curthread->specific[key].data != NULL) {
 135                                 /*
 136                                  * This can happen if the key is
 137                                  * deleted via pthread_key_delete
 138                                  * without first setting the value to
 139                                  * NULL in all threads.  POSIX says
 140                                  * that the destructor is not invoked
 141                                  * in this case.
 142                                  */
 143                                 curthread->specific[key].data = NULL;
 144                                 curthread->specific_data_count--;
 145                         }
 146
 147                         /*
 148                          * If there is a destructor, call it with the
 149                          * key table entry unlocked.
 150                          */
 151                         if (destructor != NULL) {
 152                                 THR_LOCK_RELEASE(curthread, &_keytable_lock);
 153                                 destructor(__DECONST(void *, data));
 154                                 THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 155                         }
 156                 }
 157         }
 158         THR_LOCK_RELEASE(curthread, &_keytable_lock);
 159         __thr_free(curthread->specific);
 160         curthread->specific = NULL;
 161         if (curthread->specific_data_count > 0) {
 162                 stderr_debug("Thread %p has exited with leftover "
 163                     "thread-specific data after %d destructor iterations\n",
 164                     curthread, PTHREAD_DESTRUCTOR_ITERATIONS);
 165         }
 166 }
 167
 168 int
 169 _thr_setspecific(pthread_key_t userkey, const void *value)
 170 {
 171         struct pthread *pthread;
 172         void *tmp;
 173         pthread_key_t key;
 174
 175         key = userkey - 1;
 176         if ((unsigned int)key >= PTHREAD_KEYS_MAX ||
 177             !_thread_keytable[key].allocated)
 178                 return (EINVAL);
 179
 180         pthread = _get_curthread();
 181         if (pthread->specific == NULL) {
 182                 tmp = __thr_calloc(PTHREAD_KEYS_MAX,
 183                     sizeof(struct pthread_specific_elem));
 184                 if (tmp == NULL)
 185                         return (ENOMEM);
 186                 pthread->specific = tmp;
 187         }
 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 = _thread_keytable[key].seqno;
 195         return (0);
 196 }
 197
 198 void *
 199 _thr_getspecific(pthread_key_t userkey)
 200 {
 201         struct pthread *pthread;
 202         const void *data;
 203         pthread_key_t key;
 204
 205         /* Check if there is specific data. */
 206         key = userkey - 1;
 207         if ((unsigned int)key >= PTHREAD_KEYS_MAX)
 208                 return (NULL);
 209
 210         pthread = _get_curthread();
 211         /* Check if this key has been used before. */
 212         if (_thread_keytable[key].allocated && pthread->specific != NULL &&
 213             pthread->specific[key].seqno == _thread_keytable[key].seqno) {
 214                 /* Return the value: */
 215                 data = pthread->specific[key].data;
 216         } else {
 217                 /*
 218                  * This key has not been used before, so return NULL
 219                  * instead.
 220                  */
 221                 data = NULL;
 222         }
 223         return (__DECONST(void *, data));
 224 }
 225
 226 void
 227 _thr_tsd_unload(struct dl_phdr_info *phdr_info)
 228 {
 229         struct pthread *curthread;
 230         void (*destructor)(void *);
 231         int key;
 232
 233         curthread = _get_curthread();
 234         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 235         for (key = 0; key < PTHREAD_KEYS_MAX; key++) {
 236                 if (!_thread_keytable[key].allocated)
 237                         continue;
 238                 destructor = _thread_keytable[key].destructor;
 239                 if (destructor == NULL)
 240                         continue;
 241                 if (__elf_phdr_match_addr(phdr_info, destructor))
 242                         _thread_keytable[key].destructor = NULL;
 243         }
 244         THR_LOCK_RELEASE(curthread, &_keytable_lock);
 245 }