nptl/sem_init.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 <semaphore.h>
  21 #include <shlib-compat.h>
  22 #include "semaphoreP.h"
  23 #include <kernel-features.h>
  24 #include <futex-internal.h>
  25
  26
  27 int
  28 __new_sem_init (sem_t *sem, int pshared, unsigned int value)
  29 {
  30   /* Parameter sanity check.  */
  31   if (__glibc_unlikely (value > SEM_VALUE_MAX))
  32     {
  33       __set_errno (EINVAL);
  34       return -1;
  35     }
  36   pshared = pshared != 0 ? PTHREAD_PROCESS_SHARED : PTHREAD_PROCESS_PRIVATE;
  37   int err = futex_supports_pshared (pshared);
  38   if (err != 0)
  39     {
  40       __set_errno (err);
  41       return -1;
  42     }
  43
  44   /* Map to the internal type.  */
  45   struct new_sem *isem = (struct new_sem *) sem;
  46
  47   /* Use the values the caller provided.  */
  48 #if __HAVE_64B_ATOMICS
  49   isem->data = value;
  50 #else
  51   isem->value = value << SEM_VALUE_SHIFT;
  52   /* pad is used as a mutex on pre-v9 sparc and ignored otherwise.  */
  53   isem->pad = 0;
  54   isem->nwaiters = 0;
  55 #endif
  56
  57   isem->private = (pshared == PTHREAD_PROCESS_PRIVATE
  58                    ? FUTEX_PRIVATE : FUTEX_SHARED);
  59
  60   return 0;
  61 }
  62 versioned_symbol (libpthread, __new_sem_init, sem_init, GLIBC_2_1);
  63
  64
  65
  66 #if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
  67 int
  68 attribute_compat_text_section
  69 __old_sem_init (sem_t *sem, int pshared, unsigned int value)
  70 {
  71   /* Parameter sanity check.  */
  72   if (__glibc_unlikely (value > SEM_VALUE_MAX))
  73     {
  74       __set_errno (EINVAL);
  75       return -1;
  76     }
  77
  78   /* Map to the internal type.  */
  79   struct old_sem *isem = (struct old_sem *) sem;
  80
  81   /* Use the value the user provided.  */
  82   isem->value = value;
  83
  84   /* We cannot store the PSHARED attribute.  So we always use the
  85      operations needed for shared semaphores.  */
  86
  87   return 0;
  88 }
  89 compat_symbol (libpthread, __old_sem_init, sem_init, GLIBC_2_0);
  90 #endif