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(_pthread_key_create, pthread_key_create);
  51 __weak_reference(_pthread_key_delete, pthread_key_delete);
  52 __weak_reference(_pthread_getspecific, pthread_getspecific);
  53 __weak_reference(_pthread_setspecific, pthread_setspecific);
  54
  55
  56 int
  57 _pthread_key_create(pthread_key_t *key, void (*destructor)(void *))
  58 {
  59         struct pthread *curthread;
  60         int i;
  61
  62         _thr_check_init();
  63
  64         curthread = _get_curthread();
  65
  66         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
  67         for (i = 0; i < PTHREAD_KEYS_MAX; i++) {
  68
  69                 if (_thread_keytable[i].allocated == 0) {
  70                         _thread_keytable[i].allocated = 1;
  71                         _thread_keytable[i].destructor = destructor;
  72                         _thread_keytable[i].seqno++;
  73
  74                         THR_LOCK_RELEASE(curthread, &_keytable_lock);
  75                         *key = i + 1;
  76                         return (0);
  77                 }
  78
  79         }
  80         THR_LOCK_RELEASE(curthread, &_keytable_lock);
  81         return (EAGAIN);
  82 }
  83
  84 int
  85 _pthread_key_delete(pthread_key_t userkey)
  86 {
  87         struct pthread *curthread;
  88         int key, ret;
  89
  90         key = userkey - 1;
  91         if ((unsigned int)key >= PTHREAD_KEYS_MAX)
  92                 return (EINVAL);
  93         curthread = _get_curthread();
  94         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
  95         if (_thread_keytable[key].allocated) {
  96                 _thread_keytable[key].allocated = 0;
  97                 ret = 0;
  98         } else {
  99                 ret = EINVAL;
 100         }
 101         THR_LOCK_RELEASE(curthread, &_keytable_lock);
 102         return (ret);
 103 }
 104
 105 void
 106 _thread_cleanupspecific(void)
 107 {
 108         struct pthread *curthread;
 109         void (*destructor)(void *);
 110         const void *data;
 111         int i, key;
 112
 113         curthread = _get_curthread();
 114         if (curthread->specific == NULL)
 115                 return;
 116         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 117         for (i = 0; i < PTHREAD_DESTRUCTOR_ITERATIONS &&
 118             curthread->specific_data_count > 0; i++) {
 119                 for (key = 0; key < PTHREAD_KEYS_MAX &&
 120                     curthread->specific_data_count > 0; key++) {
 121                         destructor = NULL;
 122
 123                         if (_thread_keytable[key].allocated &&
 124                             (curthread->specific[key].data != NULL)) {
 125                                 if (curthread->specific[key].seqno ==
 126                                     _thread_keytable[key].seqno) {
 127                                         data = curthread->specific[key].data;
 128                                         destructor = _thread_keytable[key].
 129                                             destructor;
 130                                 }
 131                                 curthread->specific[key].data = NULL;
 132                                 curthread->specific_data_count--;
 133                         } else if (curthread->specific[key].data != NULL) {
 134                                 /*
 135                                  * This can happen if the key is
 136                                  * deleted via pthread_key_delete
 137                                  * without first setting the value to
 138                                  * NULL in all threads.  POSIX says
 139                                  * that the destructor is not invoked
 140                                  * 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 with the
 148                          * key table entry unlocked.
 149                          */
 150                         if (destructor != NULL) {
 151                                 THR_LOCK_RELEASE(curthread, &_keytable_lock);
 152                                 destructor(__DECONST(void *, data));
 153                                 THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 154                         }
 155                 }
 156         }
 157         THR_LOCK_RELEASE(curthread, &_keytable_lock);
 158         munmap(curthread->specific, PTHREAD_KEYS_MAX * sizeof(struct
 159             pthread_specific_elem));
 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 _pthread_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 = mmap(NULL, PTHREAD_KEYS_MAX *
 183                     sizeof(struct pthread_specific_elem),
 184                     PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
 185                 if (tmp == MAP_FAILED)
 186                         return (ENOMEM);
 187                 pthread->specific = tmp;
 188         }
 189         if (pthread->specific[key].data == NULL) {
 190                 if (value != NULL)
 191                         pthread->specific_data_count++;
 192         } else if (value == NULL)
 193                 pthread->specific_data_count--;
 194         pthread->specific[key].data = value;
 195         pthread->specific[key].seqno = _thread_keytable[key].seqno;
 196         return (0);
 197 }
 198
 199 void *
 200 _pthread_getspecific(pthread_key_t userkey)
 201 {
 202         struct pthread *pthread;
 203         const void *data;
 204         pthread_key_t key;
 205
 206         /* Check if there is specific data. */
 207         key = userkey - 1;
 208         if ((unsigned int)key >= PTHREAD_KEYS_MAX)
 209                 return (NULL);
 210
 211         pthread = _get_curthread();
 212         /* Check if this key has been used before. */
 213         if (_thread_keytable[key].allocated && pthread->specific != NULL &&
 214             pthread->specific[key].seqno == _thread_keytable[key].seqno) {
 215                 /* Return the value: */
 216                 data = pthread->specific[key].data;
 217         } else {
 218                 /*
 219                  * This key has not been used before, so return NULL
 220                  * instead.
 221                  */
 222                 data = NULL;
 223         }
 224         return (__DECONST(void *, data));
 225 }
 226
 227 void
 228 _thr_tsd_unload(struct dl_phdr_info *phdr_info)
 229 {
 230         struct pthread *curthread;
 231         void (*destructor)(void *);
 232         int key;
 233
 234         curthread = _get_curthread();
 235         THR_LOCK_ACQUIRE(curthread, &_keytable_lock);
 236         for (key = 0; key < PTHREAD_KEYS_MAX; key++) {
 237                 if (!_thread_keytable[key].allocated)
 238                         continue;
 239                 destructor = _thread_keytable[key].destructor;
 240                 if (destructor == NULL)
 241                         continue;
 242                 if (__elf_phdr_match_addr(phdr_info, destructor))
 243                         _thread_keytable[key].destructor = NULL;
 244         }
 245         THR_LOCK_RELEASE(curthread, &_keytable_lock);
 246 }