1/* clock_getres -- Get the resolution of a POSIX clockid_t. Linux version.
2 Copyright (C) 2003-2021 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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 <sysdep.h>
20#include <errno.h>
21#include <time.h>
22
23#include <sysdep-vdso.h>
24#include <time64-support.h>
25#include <shlib-compat.h>
26#include <kernel-features.h>
27
28/* Get resolution of clock. */
29int
30__clock_getres64 (clockid_t clock_id, struct __timespec64 *res)
31{
32 int r;
33
34#ifndef __NR_clock_getres_time64
35# define __NR_clock_getres_time64 __NR_clock_getres
36#endif
37 if (supports_time64 ())
38 {
39#ifdef HAVE_CLOCK_GETRES64_VSYSCALL
40 r = INLINE_VSYSCALL (clock_getres_time64, 2, clock_id, res);
41#else
42 r = INLINE_SYSCALL_CALL (clock_getres_time64, clock_id, res);
43#endif
44
45 if (r == 0 || errno != ENOSYS)
46 return r;
47
48 mark_time64_unsupported ();
49 }
50
51#ifndef __ASSUME_TIME64_SYSCALLS
52 /* Fallback code that uses 32-bit support. */
53 struct timespec ts32;
54# ifdef HAVE_CLOCK_GETRES_VSYSCALL
55 r = INLINE_VSYSCALL (clock_getres, 2, clock_id, &ts32);
56# else
57 r = INLINE_SYSCALL_CALL (clock_getres, clock_id, &ts32);
58# endif
59 if (r == 0)
60 *res = valid_timespec_to_timespec64 (ts32);
61#endif
62
63 return r;
64}
65
66#if __TIMESIZE != 64
67libc_hidden_def (__clock_getres64)
68
69int
70__clock_getres (clockid_t clock_id, struct timespec *res)
71{
72 struct __timespec64 ts64;
73 int retval;
74
75 retval = __clock_getres64 (clock_id, &ts64);
76 if (retval == 0 && res != NULL)
77 *res = valid_timespec64_to_timespec (ts64);
78
79 return retval;
80}
81#endif
82
83versioned_symbol (libc, __clock_getres, clock_getres, GLIBC_2_17);
84/* clock_getres moved to libc in version 2.17;
85 old binaries may expect the symbol version it had in librt. */
86#if SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_17)
87strong_alias (__clock_getres, __clock_getres_2);
88compat_symbol (libc, __clock_getres_2, clock_getres, GLIBC_2_2);
89#endif
90