nptl/pthread_setspecific.c

   1 /* Copyright (C) 2002-2021 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <stdlib.h>
  20 #include "pthreadP.h"
  21 #include <shlib-compat.h>
  22
  23 int
  24 ___pthread_setspecific (pthread_key_t key, const void *value)
  25 {
  26   struct pthread *self;
  27   unsigned int idx1st;
  28   unsigned int idx2nd;
  29   struct pthread_key_data *level2;
  30   unsigned int seq;
  31
  32   self = THREAD_SELF;
  33
  34   /* Special case access to the first 2nd-level block.  This is the
  35      usual case.  */
  36   if (__glibc_likely (key < PTHREAD_KEY_2NDLEVEL_SIZE))
  37     {
  38       /* Verify the key is sane.  */
  39       if (KEY_UNUSED ((seq = __pthread_keys[key].seq)))
  40         /* Not valid.  */
  41         return EINVAL;
  42
  43       level2 = &self->specific_1stblock[key];
  44
  45       /* Remember that we stored at least one set of data.  */
  46       if (value != NULL)
  47         THREAD_SETMEM (self, specific_used, true);
  48     }
  49   else
  50     {
  51       if (key >= PTHREAD_KEYS_MAX
  52           || KEY_UNUSED ((seq = __pthread_keys[key].seq)))
  53         /* Not valid.  */
  54         return EINVAL;
  55
  56       idx1st = key / PTHREAD_KEY_2NDLEVEL_SIZE;
  57       idx2nd = key % PTHREAD_KEY_2NDLEVEL_SIZE;
  58
  59       /* This is the second level array.  Allocate it if necessary.  */
  60       level2 = THREAD_GETMEM_NC (self, specific, idx1st);
  61       if (level2 == NULL)
  62         {
  63           if (value == NULL)
  64             /* We don't have to do anything.  The value would in any case
  65                be NULL.  We can save the memory allocation.  */
  66             return 0;
  67
  68           level2
  69             = (struct pthread_key_data *) calloc (PTHREAD_KEY_2NDLEVEL_SIZE,
  70                                                   sizeof (*level2));
  71           if (level2 == NULL)
  72             return ENOMEM;
  73
  74           THREAD_SETMEM_NC (self, specific, idx1st, level2);
  75         }
  76
  77       /* Pointer to the right array element.  */
  78       level2 = &level2[idx2nd];
  79
  80       /* Remember that we stored at least one set of data.  */
  81       THREAD_SETMEM (self, specific_used, true);
  82     }
  83
  84   /* Store the data and the sequence number so that we can recognize
  85      stale data.  */
  86   level2->seq = seq;
  87   level2->data = (void *) value;
  88
  89   return 0;
  90 }
  91 versioned_symbol (libc, ___pthread_setspecific, pthread_setspecific,
  92                   GLIBC_2_34);
  93 libc_hidden_ver (___pthread_setspecific, __pthread_setspecific)
  94 #ifndef SHARED
  95 strong_alias (___pthread_setspecific, __pthread_setspecific)
  96 #endif
  97
  98 #if OTHER_SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_34)
  99 compat_symbol (libpthread, ___pthread_setspecific, __pthread_setspecific,
 100                GLIBC_2_0);
 101 compat_symbol (libpthread, ___pthread_setspecific, pthread_setspecific,
 102                GLIBC_2_0);
 103 #endif