1/* Copyright (C) 2002-2020 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 <semaphore.h>
20#include <shlib-compat.h>
21#include "semaphoreP.h"
22#include <atomic.h>
23
24
25int
26__new_sem_getvalue (sem_t *sem, int *sval)
27{
28 struct new_sem *isem = (struct new_sem *) sem;
29
30 /* XXX Check for valid SEM parameter. */
31 /* FIXME This uses relaxed MO, even though POSIX specifies that this function
32 should be linearizable. However, its debatable whether linearizability
33 is the right requirement. We need to follow up with POSIX and, if
34 necessary, use a stronger MO here and elsewhere (e.g., potentially
35 release MO in all places where we consume a token). */
36
37#if __HAVE_64B_ATOMICS
38 *sval = atomic_load_relaxed (&isem->data) & SEM_VALUE_MASK;
39#else
40 *sval = atomic_load_relaxed (&isem->value) >> SEM_VALUE_SHIFT;
41#endif
42
43 return 0;
44}
45versioned_symbol (libpthread, __new_sem_getvalue, sem_getvalue, GLIBC_2_1);
46#if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
47int
48__old_sem_getvalue (sem_t *sem, int *sval)
49{
50 struct old_sem *isem = (struct old_sem *) sem;
51 *sval = isem->value;
52 return 0;
53}
54compat_symbol (libpthread, __old_sem_getvalue, sem_getvalue, GLIBC_2_0);
55#endif
56