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 __FBSDID("$FreeBSD$");
  34
  35 #include "namespace.h"
  36 #include <sys/mman.h>
  37 #include <signal.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <errno.h>
  41 #include <pthread.h>
  42 #include "un-namespace.h"
  43 #include "libc_private.h"
  44
  45 #include "thr_private.h"
  46
  47 /* Used in symbol lookup of libthread_db */
  48 struct pthread_key _thread_keytable[PTHREAD_KEYS_MAX];
  49
  50 __weak_reference(_thr_key_create, pthread_key_create);
  51 __weak_reference(_thr_key_create, _pthread_key_create);
  52 __weak_reference(_thr_key_delete, pthread_key_delete);
  53 __weak_reference(_thr_key_delete, _pthread_key_delete);
  54 __weak_reference(_thr_getspecific, pthread_getspecific);
  55 __weak_reference(_thr_getspecific, _pthread_getspecific);
  56 __weak_reference(_thr_setspecific, pthread_setspecific);
  57 __weak_reference(_thr_setspecific, _pthread_setspecific);
  58
  59 int
  60 _thr_key_create(pthread_key_t *key, void (*destructor)(void *))
  61 {
  62         struct pthread *curthread;
  63         int i;
  64
  65         _thr_check_init();
  66
  67         curthread = _get_curthread();
  68
  69         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
  70         for (i = 0; i < PTHREAD_KEYS_MAX; i++) {
  71
  72                 if (_thread_keytable[i].allocated == 0) {
  73                         _thread_keytable[i].allocated = 1;
  74                         _thread_keytable[i].destructor = destructor;
  75                         _thread_keytable[i].seqno++;
  76
  77                         THR_LOCK_RELEASE(curthread, &_keytable_lock);
  78                         *key = i + 1;
  79                         return (0);
  80                 }
  81
  82         }
  83         THR_LOCK_RELEASE(curthread, &_keytable_lock);
  84         return (EAGAIN);
  85 }
  86
  87 int
  88 _thr_key_delete(pthread_key_t userkey)
  89 {
  90         struct pthread *curthread;
  91         int key, ret;
  92
  93         key = userkey - 1;
  94         if ((unsigned int)key >= PTHREAD_KEYS_MAX)
  95                 return (EINVAL);
  96         curthread = _get_curthread();
  97         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
  98         if (_thread_keytable[key].allocated) {
  99                 _thread_keytable[key].allocated = 0;
 100                 ret = 0;
 101         } else {
 102                 ret = EINVAL;
 103         }
 104         THR_LOCK_RELEASE(curthread, &_keytable_lock);
 105         return (ret);
 106 }
 107
 108 void
 109 _thread_cleanupspecific(void)
 110 {
 111         struct pthread *curthread;
 112         void (*destructor)(void *);
 113         const void *data;
 114         int i, key;
 115
 116         curthread = _get_curthread();
 117         if (curthread->specific == NULL)
 118                 return;
 119         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 120         for (i = 0; i < PTHREAD_DESTRUCTOR_ITERATIONS &&
 121             curthread->specific_data_count > 0; i++) {
 122                 for (key = 0; key < PTHREAD_KEYS_MAX &&
 123                     curthread->specific_data_count > 0; key++) {
 124                         destructor = NULL;
 125
 126                         if (_thread_keytable[key].allocated &&
 127                             (curthread->specific[key].data != NULL)) {
 128                                 if (curthread->specific[key].seqno ==
 129                                     _thread_keytable[key].seqno) {
 130                                         data = curthread->specific[key].data;
 131                                         destructor = _thread_keytable[key].
 132                                             destructor;
 133                                 }
 134                                 curthread->specific[key].data = NULL;
 135                                 curthread->specific_data_count--;
 136                         } else if (curthread->specific[key].data != NULL) {
 137                                 /*
 138                                  * This can happen if the key is
 139                                  * deleted via pthread_key_delete
 140                                  * without first setting the value to
 141                                  * NULL in all threads.  POSIX says
 142                                  * that the destructor is not invoked
 143                                  * in this case.
 144                                  */
 145                                 curthread->specific[key].data = NULL;
 146                                 curthread->specific_data_count--;
 147                         }
 148
 149                         /*
 150                          * If there is a destructor, call it with the
 151                          * key table entry unlocked.
 152                          */
 153                         if (destructor != NULL) {
 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         __thr_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
 170 int
 171 _thr_setspecific(pthread_key_t userkey, const void *value)
 172 {
 173         struct pthread *pthread;
 174         void *tmp;
 175         pthread_key_t key;
 176
 177         key = userkey - 1;
 178         if ((unsigned int)key >= PTHREAD_KEYS_MAX ||
 179             !_thread_keytable[key].allocated)
 180                 return (EINVAL);
 181
 182         pthread = _get_curthread();
 183         if (pthread->specific == NULL) {
 184                 tmp = __thr_calloc(PTHREAD_KEYS_MAX,
 185                     sizeof(struct pthread_specific_elem));
 186                 if (tmp == NULL)
 187                         return (ENOMEM);
 188                 pthread->specific = tmp;
 189         }
 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 = _thread_keytable[key].seqno;
 197         return (0);
 198 }
 199
 200 void *
 201 _thr_getspecific(pthread_key_t userkey)
 202 {
 203         struct pthread *pthread;
 204         const void *data;
 205         pthread_key_t key;
 206
 207         /* Check if there is specific data. */
 208         key = userkey - 1;
 209         if ((unsigned int)key >= PTHREAD_KEYS_MAX)
 210                 return (NULL);
 211
 212         pthread = _get_curthread();
 213         /* Check if this key has been used before. */
 214         if (_thread_keytable[key].allocated && pthread->specific != NULL &&
 215             pthread->specific[key].seqno == _thread_keytable[key].seqno) {
 216                 /* Return the value: */
 217                 data = pthread->specific[key].data;
 218         } else {
 219                 /*
 220                  * This key has not been used before, so return NULL
 221                  * instead.
 222                  */
 223                 data = NULL;
 224         }
 225         return (__DECONST(void *, data));
 226 }
 227
 228 void
 229 _thr_tsd_unload(struct dl_phdr_info *phdr_info)
 230 {
 231         struct pthread *curthread;
 232         void (*destructor)(void *);
 233         int key;
 234
 235         curthread = _get_curthread();
 236         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 237         for (key = 0; key < PTHREAD_KEYS_MAX; key++) {
 238                 if (!_thread_keytable[key].allocated)
 239                         continue;
 240                 destructor = _thread_keytable[key].destructor;
 241                 if (destructor == NULL)
 242                         continue;
 243                 if (__elf_phdr_match_addr(phdr_info, destructor))
 244                         _thread_keytable[key].destructor = NULL;
 245         }
 246         THR_LOCK_RELEASE(curthread, &_keytable_lock);
 247 }