nptl/pthread_setspecific.c

   1 /* Copyright (C) 2002-2012 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <stdlib.h>
  21 #include "pthreadP.h"
  22
  23
  24 int
  25 __pthread_setspecific (key, value)
  26      pthread_key_t key;
  27      const void *value;
  28 {
  29   struct pthread *self;
  30   unsigned int idx1st;
  31   unsigned int idx2nd;
  32   struct pthread_key_data *level2;
  33   unsigned int seq;
  34
  35   self = THREAD_SELF;
  36
  37   /* Special case access to the first 2nd-level block.  This is the
  38      usual case.  */
  39   if (__builtin_expect (key < PTHREAD_KEY_2NDLEVEL_SIZE, 1))
  40     {
  41       /* Verify the key is sane.  */
  42       if (KEY_UNUSED ((seq = __pthread_keys[key].seq)))
  43         /* Not valid.  */
  44         return EINVAL;
  45
  46       level2 = &self->specific_1stblock[key];
  47
  48       /* Remember that we stored at least one set of data.  */
  49       if (value != NULL)
  50         THREAD_SETMEM (self, specific_used, true);
  51     }
  52   else
  53     {
  54       if (key >= PTHREAD_KEYS_MAX
  55           || KEY_UNUSED ((seq = __pthread_keys[key].seq)))
  56         /* Not valid.  */
  57         return EINVAL;
  58
  59       idx1st = key / PTHREAD_KEY_2NDLEVEL_SIZE;
  60       idx2nd = key % PTHREAD_KEY_2NDLEVEL_SIZE;
  61
  62       /* This is the second level array.  Allocate it if necessary.  */
  63       level2 = THREAD_GETMEM_NC (self, specific, idx1st);
  64       if (level2 == NULL)
  65         {
  66           if (value == NULL)
  67             /* We don't have to do anything.  The value would in any case
  68                be NULL.  We can save the memory allocation.  */
  69             return 0;
  70
  71           level2
  72             = (struct pthread_key_data *) calloc (PTHREAD_KEY_2NDLEVEL_SIZE,
  73                                                   sizeof (*level2));
  74           if (level2 == NULL)
  75             return ENOMEM;
  76
  77           THREAD_SETMEM_NC (self, specific, idx1st, level2);
  78         }
  79
  80       /* Pointer to the right array element.  */
  81       level2 = &level2[idx2nd];
  82
  83       /* Remember that we stored at least one set of data.  */
  84       THREAD_SETMEM (self, specific_used, true);
  85     }
  86
  87   /* Store the data and the sequence number so that we can recognize
  88      stale data.  */
  89   level2->seq = seq;
  90   level2->data = (void *) value;
  91
  92   return 0;
  93 }
  94 strong_alias (__pthread_setspecific, pthread_setspecific)
  95 hidden_def (__pthread_setspecific)