linuxthreads/specific.c

   1 /* Linuxthreads - a simple clone()-based implementation of Posix        */
   2 /* threads for Linux.                                                   */
   3 /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */
   4 /*                                                                      */
   5 /* This program is free software; you can redistribute it and/or        */
   6 /* modify it under the terms of the GNU Library General Public License  */
   7 /* as published by the Free Software Foundation; either version 2       */
   8 /* of the License, or (at your option) any later version.               */
   9 /*                                                                      */
  10 /* This program is distributed in the hope that it will be useful,      */
  11 /* but WITHOUT ANY WARRANTY; without even the implied warranty of       */
  12 /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        */
  13 /* GNU Library General Public License for more details.                 */
  14
  15 /* Thread-specific data */
  16
  17 #include <errno.h>
  18 #include <stddef.h>
  19 #include <stdlib.h>
  20 #include "pthread.h"
  21 #include "internals.h"
  22
  23 typedef void (*destr_function)(void *);
  24
  25 /* Table of keys. */
  26
  27 struct pthread_key_struct {
  28   int in_use;                   /* already allocated? */
  29   destr_function destr;         /* destruction routine */
  30 };
  31
  32 static struct pthread_key_struct pthread_keys[PTHREAD_KEYS_MAX] =
  33   { { 0, NULL } };
  34
  35 /* Mutex to protect access to pthread_keys */
  36
  37 static pthread_mutex_t pthread_keys_mutex = PTHREAD_MUTEX_INITIALIZER;
  38
  39 /* Create a new key */
  40
  41 int __pthread_key_create(pthread_key_t * key, destr_function destr)
  42 {
  43   int i;
  44
  45   pthread_mutex_lock(&pthread_keys_mutex);
  46   for (i = 0; i < PTHREAD_KEYS_MAX; i++) {
  47     if (! pthread_keys[i].in_use) {
  48       /* Mark key in use */
  49       pthread_keys[i].in_use = 1;
  50       pthread_keys[i].destr = destr;
  51       pthread_mutex_unlock(&pthread_keys_mutex);
  52       *key = i;
  53       return 0;
  54     }
  55   }
  56   pthread_mutex_unlock(&pthread_keys_mutex);
  57   return EAGAIN;
  58 }
  59 weak_alias (__pthread_key_create, pthread_key_create)
  60
  61 /* Delete a key */
  62
  63 int pthread_key_delete(pthread_key_t key)
  64 {
  65   pthread_descr self = thread_self();
  66   pthread_descr th;
  67   unsigned int idx1st, idx2nd;
  68
  69   pthread_mutex_lock(&pthread_keys_mutex);
  70   if (key >= PTHREAD_KEYS_MAX || !pthread_keys[key].in_use) {
  71     pthread_mutex_unlock(&pthread_keys_mutex);
  72     return EINVAL;
  73   }
  74   pthread_keys[key].in_use = 0;
  75   pthread_keys[key].destr = NULL;
  76   /* Set the value of the key to NULL in all running threads, so that
  77      if the key is reallocated later by pthread_key_create, its
  78      associated values will be NULL in all threads. */
  79   idx1st = key / PTHREAD_KEY_2NDLEVEL_SIZE;
  80   idx2nd = key % PTHREAD_KEY_2NDLEVEL_SIZE;
  81   th = self;
  82   do {
  83     if (th->p_specific[idx1st] != NULL)
  84       th->p_specific[idx1st][idx2nd] = NULL;
  85     th = th->p_nextlive;
  86   } while (th != self);
  87   pthread_mutex_unlock(&pthread_keys_mutex);
  88   return 0;
  89 }
  90
  91 /* Set the value of a key */
  92
  93 int __pthread_setspecific(pthread_key_t key, const void * pointer)
  94 {
  95   pthread_descr self = thread_self();
  96   unsigned int idx1st, idx2nd;
  97
  98   if (key >= PTHREAD_KEYS_MAX || !pthread_keys[key].in_use)
  99     return EINVAL;
 100   idx1st = key / PTHREAD_KEY_2NDLEVEL_SIZE;
 101   idx2nd = key % PTHREAD_KEY_2NDLEVEL_SIZE;
 102   if (THREAD_GETMEM_NC(self, p_specific[idx1st]) == NULL) {
 103     void *newp = calloc(PTHREAD_KEY_2NDLEVEL_SIZE, sizeof (void *));
 104     if (newp == NULL)
 105       return ENOMEM;
 106     THREAD_SETMEM_NC(self, p_specific[idx1st], newp);
 107   }
 108   THREAD_GETMEM_NC(self, p_specific[idx1st])[idx2nd] = (void *) pointer;
 109   return 0;
 110 }
 111 weak_alias (__pthread_setspecific, pthread_setspecific)
 112
 113 /* Get the value of a key */
 114
 115 void * __pthread_getspecific(pthread_key_t key)
 116 {
 117   pthread_descr self = thread_self();
 118   unsigned int idx1st, idx2nd;
 119
 120   if (key >= PTHREAD_KEYS_MAX)
 121     return NULL;
 122   idx1st = key / PTHREAD_KEY_2NDLEVEL_SIZE;
 123   idx2nd = key % PTHREAD_KEY_2NDLEVEL_SIZE;
 124   if (THREAD_GETMEM_NC(self, p_specific[idx1st]) == NULL
 125       || !pthread_keys[key].in_use)
 126     return NULL;
 127   return THREAD_GETMEM_NC(self, p_specific[idx1st])[idx2nd];
 128 }
 129 weak_alias (__pthread_getspecific, pthread_getspecific)
 130
 131 /* Call the destruction routines on all keys */
 132
 133 void __pthread_destroy_specifics()
 134 {
 135   pthread_descr self = thread_self();
 136   int i, j, round, found_nonzero;
 137   destr_function destr;
 138   void * data;
 139
 140   for (round = 0, found_nonzero = 1;
 141        found_nonzero && round < PTHREAD_DESTRUCTOR_ITERATIONS;
 142        round++) {
 143     found_nonzero = 0;
 144     for (i = 0; i < PTHREAD_KEY_1STLEVEL_SIZE; i++)
 145       if (THREAD_GETMEM_NC(self, p_specific[i]) != NULL)
 146         for (j = 0; j < PTHREAD_KEY_2NDLEVEL_SIZE; j++) {
 147           destr = pthread_keys[i * PTHREAD_KEY_2NDLEVEL_SIZE + j].destr;
 148           data = THREAD_GETMEM_NC(self, p_specific[i])[j];
 149           if (destr != NULL && data != NULL) {
 150             THREAD_GETMEM_NC(self, p_specific[i])[j] = NULL;
 151             destr(data);
 152             found_nonzero = 1;
 153           }
 154         }
 155   }
 156   for (i = 0; i < PTHREAD_KEY_1STLEVEL_SIZE; i++) {
 157     if (THREAD_GETMEM_NC(self, p_specific[i]) != NULL)
 158       free(THREAD_GETMEM_NC(self, p_specific[i]));
 159   }
 160 }
 161
 162 /* Thread-specific data for libc. */
 163
 164 int __libc_internal_tsd_set(enum __libc_tsd_key_t key, const void * pointer)
 165 {
 166   pthread_descr self = thread_self();
 167
 168   THREAD_SETMEM_NC(self, p_libc_specific[key], (void *) pointer);
 169   return 0;
 170 }
 171
 172 void * __libc_internal_tsd_get(enum __libc_tsd_key_t key)
 173 {
 174   pthread_descr self = thread_self();
 175
 176   return THREAD_GETMEM_NC(self, p_libc_specific[key]);
 177 }