nptl/sem_init.c

   1 /* Copyright (C) 2002-2022 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 <semaphore.h>
  20 #include <shlib-compat.h>
  21 #include "semaphoreP.h"
  22 #include <kernel-features.h>
  23 #include <futex-internal.h>
  24
  25
  26 int
  27 __new_sem_init (sem_t *sem, int pshared, unsigned int value)
  28 {
  29   ASSERT_PTHREAD_INTERNAL_SIZE (sem_t, struct new_sem);
  30
  31   /* Parameter sanity check.  */
  32   if (__glibc_unlikely (value > SEM_VALUE_MAX))
  33     {
  34       __set_errno (EINVAL);
  35       return -1;
  36     }
  37   pshared = pshared != 0 ? PTHREAD_PROCESS_SHARED : PTHREAD_PROCESS_PRIVATE;
  38   int err = futex_supports_pshared (pshared);
  39   if (err != 0)
  40     {
  41       __set_errno (err);
  42       return -1;
  43     }
  44
  45   /* Map to the internal type.  */
  46   struct new_sem *isem = (struct new_sem *) sem;
  47
  48   /* Use the values the caller provided.  */
  49 #if __HAVE_64B_ATOMICS
  50   isem->data = value;
  51 #else
  52   isem->value = value << SEM_VALUE_SHIFT;
  53   /* pad is used as a mutex on pre-v9 sparc and ignored otherwise.  */
  54   isem->pad = 0;
  55   isem->nwaiters = 0;
  56 #endif
  57
  58   isem->private = (pshared == PTHREAD_PROCESS_PRIVATE
  59                    ? FUTEX_PRIVATE : FUTEX_SHARED);
  60
  61   return 0;
  62 }
  63 versioned_symbol (libc, __new_sem_init, sem_init, GLIBC_2_34);
  64
  65 #if OTHER_SHLIB_COMPAT(libpthread, GLIBC_2_1, GLIBC_2_34)
  66 compat_symbol (libpthread, __new_sem_init, sem_init, GLIBC_2_1);
  67 #endif
  68
  69 #if OTHER_SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
  70 int
  71 attribute_compat_text_section
  72 __old_sem_init (sem_t *sem, int pshared, unsigned int value)
  73 {
  74   ASSERT_PTHREAD_INTERNAL_SIZE (sem_t, struct new_sem);
  75
  76   /* Parameter sanity check.  */
  77   if (__glibc_unlikely (value > SEM_VALUE_MAX))
  78     {
  79       __set_errno (EINVAL);
  80       return -1;
  81     }
  82
  83   /* Map to the internal type.  */
  84   struct old_sem *isem = (struct old_sem *) sem;
  85
  86   /* Use the value the user provided.  */
  87   isem->value = value;
  88
  89   /* We cannot store the PSHARED attribute.  So we always use the
  90      operations needed for shared semaphores.  */
  91
  92   return 0;
  93 }
  94 compat_symbol (libpthread, __old_sem_init, sem_init, GLIBC_2_0);
  95 #endif