nptl/sem_init.c

   1 /* Copyright (C) 2002-2021 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    <https://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   ASSERT_PTHREAD_INTERNAL_SIZE (sem_t, struct new_sem);
  31
  32   /* Parameter sanity check.  */
  33   if (__glibc_unlikely (value > SEM_VALUE_MAX))
  34     {
  35       __set_errno (EINVAL);
  36       return -1;
  37     }
  38   pshared = pshared != 0 ? PTHREAD_PROCESS_SHARED : PTHREAD_PROCESS_PRIVATE;
  39   int err = futex_supports_pshared (pshared);
  40   if (err != 0)
  41     {
  42       __set_errno (err);
  43       return -1;
  44     }
  45
  46   /* Map to the internal type.  */
  47   struct new_sem *isem = (struct new_sem *) sem;
  48
  49   /* Use the values the caller provided.  */
  50 #if __HAVE_64B_ATOMICS
  51   isem->data = value;
  52 #else
  53   isem->value = value << SEM_VALUE_SHIFT;
  54   /* pad is used as a mutex on pre-v9 sparc and ignored otherwise.  */
  55   isem->pad = 0;
  56   isem->nwaiters = 0;
  57 #endif
  58
  59   isem->private = (pshared == PTHREAD_PROCESS_PRIVATE
  60                    ? FUTEX_PRIVATE : FUTEX_SHARED);
  61
  62   return 0;
  63 }
  64 versioned_symbol (libpthread, __new_sem_init, sem_init, GLIBC_2_1);
  65
  66
  67
  68 #if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
  69 int
  70 attribute_compat_text_section
  71 __old_sem_init (sem_t *sem, int pshared, unsigned int value)
  72 {
  73   ASSERT_PTHREAD_INTERNAL_SIZE (sem_t, struct new_sem);
  74
  75   /* Parameter sanity check.  */
  76   if (__glibc_unlikely (value > SEM_VALUE_MAX))
  77     {
  78       __set_errno (EINVAL);
  79       return -1;
  80     }
  81
  82   /* Map to the internal type.  */
  83   struct old_sem *isem = (struct old_sem *) sem;
  84
  85   /* Use the value the user provided.  */
  86   isem->value = value;
  87
  88   /* We cannot store the PSHARED attribute.  So we always use the
  89      operations needed for shared semaphores.  */
  90
  91   return 0;
  92 }
  93 compat_symbol (libpthread, __old_sem_init, sem_init, GLIBC_2_0);
  94 #endif