1/* gettimeofday - set time. Linux version.
2 Copyright (C) 2020-2022 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 License as
7 published by the Free Software Foundation; either version 2.1 of the
8 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 <time.h>
20#include <string.h>
21
22/* Optimize the function call by setting the PLT directly to vDSO symbol. */
23#ifdef USE_IFUNC_GETTIMEOFDAY
24# include <sysdep.h>
25# include <sysdep-vdso.h>
26
27# ifdef SHARED
28# include <dl-vdso.h>
29# include <libc-vdso.h>
30
31static int
32__gettimeofday_syscall (struct timeval *restrict tv, void *restrict tz)
33{
34 if (__glibc_unlikely (tz != 0))
35 memset (tz, 0, sizeof *tz);
36 return INLINE_SYSCALL_CALL (gettimeofday, tv, tz);
37}
38
39# undef INIT_ARCH
40# define INIT_ARCH() \
41 void *vdso_gettimeofday = dl_vdso_vsym (HAVE_GETTIMEOFDAY_VSYSCALL)
42libc_ifunc (__gettimeofday,
43 vdso_gettimeofday ? VDSO_IFUNC_RET (vdso_gettimeofday)
44 : (void *) __gettimeofday_syscall)
45
46# else
47int
48__gettimeofday (struct timeval *restrict tv, void *restrict tz)
49{
50 if (__glibc_unlikely (tz != 0))
51 memset (tz, 0, sizeof *tz);
52
53 return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);
54}
55# endif
56weak_alias (__gettimeofday, gettimeofday)
57#else /* USE_IFUNC_GETTIMEOFDAY */
58/* Conversion of gettimeofday function to support 64 bit time on archs
59 with __WORDSIZE == 32 and __TIMESIZE == 32/64 */
60#include <errno.h>
61
62int
63__gettimeofday64 (struct __timeval64 *restrict tv, void *restrict tz)
64{
65 if (__glibc_unlikely (tz != 0))
66 memset (tz, 0, sizeof (struct timezone));
67
68 struct __timespec64 ts64;
69 if (__clock_gettime64 (CLOCK_REALTIME, &ts64))
70 return -1;
71
72 *tv = timespec64_to_timeval64 (ts64);
73 return 0;
74}
75
76# if __TIMESIZE != 64
77libc_hidden_def (__gettimeofday64)
78
79int
80__gettimeofday (struct timeval *restrict tv, void *restrict tz)
81{
82 struct __timeval64 tv64;
83 if (__gettimeofday64 (&tv64, tz))
84 return -1;
85
86 if (! in_time_t_range (tv64.tv_sec))
87 {
88 __set_errno (EOVERFLOW);
89 return -1;
90 }
91
92 *tv = valid_timeval64_to_timeval (tv64);
93 return 0;
94}
95# endif
96weak_alias (__gettimeofday, gettimeofday)
97#endif
98

source code of glibc/sysdeps/unix/sysv/linux/gettimeofday.c