1 /* clock_getres -- Get the resolution of a POSIX clockid_t. Linux version.
2 Copyright (C) 2003-2022 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. */
28 int
__clock_getres64(clockid_t clock_id,struct __timespec64 * res)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
libc_hidden_def(__clock_getres64)61 libc_hidden_def (__clock_getres64)
62
63 int
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
76 libc_hidden_def (__clock_getres)
77
78 versioned_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)
82 strong_alias (__clock_getres, __clock_getres_2);
83 compat_symbol (libc, __clock_getres_2, clock_getres, GLIBC_2_2);
84 #endif
85