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