nptl/pthread_setspecific.c

   1 /* Copyright (C) 2002-2017 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 (pthread_key_t key, const void *value)
  26 {
  27   struct pthread *self;
  28   unsigned int idx1st;
  29   unsigned int idx2nd;
  30   struct pthread_key_data *level2;
  31   unsigned int seq;
  32
  33   self = THREAD_SELF;
  34
  35   /* Special case access to the first 2nd-level block.  This is the
  36      usual case.  */
  37   if (__glibc_likely (key < PTHREAD_KEY_2NDLEVEL_SIZE))
  38     {
  39       /* Verify the key is sane.  */
  40       if (KEY_UNUSED ((seq = __pthread_keys[key].seq)))
  41         /* Not valid.  */
  42         return EINVAL;
  43
  44       level2 = &self->specific_1stblock[key];
  45
  46       /* Remember that we stored at least one set of data.  */
  47       if (value != NULL)
  48         THREAD_SETMEM (self, specific_used, true);
  49     }
  50   else
  51     {
  52       if (key >= PTHREAD_KEYS_MAX
  53           || KEY_UNUSED ((seq = __pthread_keys[key].seq)))
  54         /* Not valid.  */
  55         return EINVAL;
  56
  57       idx1st = key / PTHREAD_KEY_2NDLEVEL_SIZE;
  58       idx2nd = key % PTHREAD_KEY_2NDLEVEL_SIZE;
  59
  60       /* This is the second level array.  Allocate it if necessary.  */
  61       level2 = THREAD_GETMEM_NC (self, specific, idx1st);
  62       if (level2 == NULL)
  63         {
  64           if (value == NULL)
  65             /* We don't have to do anything.  The value would in any case
  66                be NULL.  We can save the memory allocation.  */
  67             return 0;
  68
  69           level2
  70             = (struct pthread_key_data *) calloc (PTHREAD_KEY_2NDLEVEL_SIZE,
  71                                                   sizeof (*level2));
  72           if (level2 == NULL)
  73             return ENOMEM;
  74
  75           THREAD_SETMEM_NC (self, specific, idx1st, level2);
  76         }
  77
  78       /* Pointer to the right array element.  */
  79       level2 = &level2[idx2nd];
  80
  81       /* Remember that we stored at least one set of data.  */
  82       THREAD_SETMEM (self, specific_used, true);
  83     }
  84
  85   /* Store the data and the sequence number so that we can recognize
  86      stale data.  */
  87   level2->seq = seq;
  88   level2->data = (void *) value;
  89
  90   return 0;
  91 }
  92 strong_alias (__pthread_setspecific, pthread_setspecific)
  93 hidden_def (__pthread_setspecific)