1/* clock_gettime -- Get current time from a POSIX clockid_t. Linux version.
2 Copyright (C) 2003-2020 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 <kernel-features.h>
21#include <errno.h>
22#include <time.h>
23#include "kernel-posix-cpu-timers.h"
24#include <sysdep-vdso.h>
25
26#include <shlib-compat.h>
27
28/* Get current value of CLOCK and store it in TP. */
29int
30__clock_gettime64 (clockid_t clock_id, struct __timespec64 *tp)
31{
32#ifdef __ASSUME_TIME64_SYSCALLS
33 /* 64 bit ABIs or newer 32-bit ABIs that only support 64-bit time_t. */
34# ifndef __NR_clock_gettime64
35# define __NR_clock_gettime64 __NR_clock_gettime
36# endif
37# ifdef HAVE_CLOCK_GETTIME64_VSYSCALL
38 return INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);
39# else
40 return INLINE_SYSCALL_CALL (clock_gettime64, clock_id, tp);
41# endif
42#else
43 int r;
44 /* Old 32-bit ABI with possible 64-bit time_t support. */
45# ifdef __NR_clock_gettime64
46 /* Avoid issue a __NR_clock_gettime64 syscall on kernels that do not
47 support 64-bit time_t. */
48 static int time64_support = 1;
49 if (atomic_load_relaxed (&time64_support) != 0)
50 {
51# ifdef HAVE_CLOCK_GETTIME64_VSYSCALL
52 r = INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);
53# else
54 r = INLINE_SYSCALL_CALL (clock_gettime64, clock_id, tp);
55# endif
56 if (r == 0 || errno != ENOSYS)
57 return r;
58
59 atomic_store_relaxed (&time64_support, 0);
60 }
61# endif
62 /* Fallback code that uses 32-bit support. */
63 struct timespec tp32;
64# ifdef HAVE_CLOCK_GETTIME_VSYSCALL
65 r = INLINE_VSYSCALL (clock_gettime, 2, clock_id, &tp32);
66# else
67 r = INLINE_SYSCALL_CALL (clock_gettime, clock_id, &tp32);
68# endif
69 if (r == 0)
70 *tp = valid_timespec_to_timespec64 (tp32);
71 return r;
72#endif
73}
74
75#if __TIMESIZE != 64
76libc_hidden_def (__clock_gettime64)
77
78int
79__clock_gettime (clockid_t clock_id, struct timespec *tp)
80{
81 int ret;
82 struct __timespec64 tp64;
83
84 ret = __clock_gettime64 (clock_id, &tp64);
85
86 if (ret == 0)
87 {
88 if (! in_time_t_range (tp64.tv_sec))
89 {
90 __set_errno (EOVERFLOW);
91 return -1;
92 }
93
94 *tp = valid_timespec64_to_timespec (tp64);
95 }
96
97 return ret;
98}
99#endif
100libc_hidden_def (__clock_gettime)
101
102versioned_symbol (libc, __clock_gettime, clock_gettime, GLIBC_2_17);
103/* clock_gettime moved to libc in version 2.17;
104 old binaries may expect the symbol version it had in librt. */
105#if SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_17)
106strong_alias (__clock_gettime, __clock_gettime_2);
107compat_symbol (libc, __clock_gettime_2, clock_gettime, GLIBC_2_2);
108#endif
109