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 <semaphore.h>
19 #include <shlib-compat.h>
20 #include "semaphoreP.h"
21 #include <atomic.h>
22
23
24 int
__new_sem_getvalue(sem_t * sem,int * sval)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
__old_sem_getvalue(sem_t * sem,int * sval)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
60