1  /* Copyright (C) 2002-2023 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 <semaphore.h>
      19  #include <shlib-compat.h>
      20  #include "semaphoreP.h"
      21  #include <atomic.h>
      22  
      23  
      24  int
      25  __new_sem_getvalue (sem_t *sem, int *sval)
      26  {
      27    struct new_sem *isem = (struct new_sem *) sem;
      28  
      29    /* XXX Check for valid SEM parameter.  */
      30    /* FIXME This uses relaxed MO, even though POSIX specifies that this function
      31       should be linearizable.  However, its debatable whether linearizability
      32       is the right requirement.  We need to follow up with POSIX and, if
      33       necessary, use a stronger MO here and elsewhere (e.g., potentially
      34       release MO in all places where we consume a token).  */
      35  
      36  #if __HAVE_64B_ATOMICS
      37    *sval = atomic_load_relaxed (&isem->data) & SEM_VALUE_MASK;
      38  #else
      39    *sval = atomic_load_relaxed (&isem->value) >> SEM_VALUE_SHIFT;
      40  #endif
      41  
      42    return 0;
      43  }
      44  versioned_symbol (libc, __new_sem_getvalue, sem_getvalue, GLIBC_2_34);
      45  
      46  #if OTHER_SHLIB_COMPAT(libpthread, GLIBC_2_1, GLIBC_2_34)
      47  compat_symbol (libpthread, __new_sem_getvalue, sem_getvalue, GLIBC_2_1);
      48  #endif
      49  
      50  #if OTHER_SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
      51  int
      52  __old_sem_getvalue (sem_t *sem, int *sval)
      53  {
      54    struct old_sem *isem = (struct old_sem *) sem;
      55    *sval = isem->value;
      56    return 0;
      57  }
      58  compat_symbol (libpthread, __old_sem_getvalue, sem_getvalue, GLIBC_2_0);
      59  #endif