glibc/sysdeps/unix/sysv/linux/clock_gettime.c
Alistair Francis ec138c67cb sysdeps/clock_gettime: Use clock_gettime64 if avaliable
With the clock_gettime64 call we prefer to use vDSO. There is no call
to clock_gettime64 on glibc with older headers and kernel 5.1+ if it
doesn't support vDSO.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2019-12-04 09:43:40 -08:00

88 lines
2.5 KiB
C

/* clock_gettime -- Get current time from a POSIX clockid_t. Linux version.
Copyright (C) 2003-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <kernel-features.h>
#include <errno.h>
#include <time.h>
#include "kernel-posix-cpu-timers.h"
#ifdef HAVE_CLOCK_GETTIME_VSYSCALL
# define HAVE_VSYSCALL
#endif
#include <sysdep-vdso.h>
#include <shlib-compat.h>
/* Get current value of CLOCK and store it in TP. */
int
__clock_gettime64 (clockid_t clock_id, struct __timespec64 *tp)
{
#ifdef __ASSUME_TIME64_SYSCALLS
# ifndef __NR_clock_gettime64
# define __NR_clock_gettime64 __NR_clock_gettime
# define __vdso_clock_gettime64 __vdso_clock_gettime
# endif
return INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);
#else
# if defined HAVE_CLOCK_GETTIME64_VSYSCALL
int ret64 = INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);
if (ret64 == 0 || errno != ENOSYS)
return ret64;
# endif
struct timespec tp32;
int ret = INLINE_VSYSCALL (clock_gettime, 2, clock_id, &tp32);
if (ret == 0)
*tp = valid_timespec_to_timespec64 (tp32);
return ret;
#endif
}
#if __TIMESIZE != 64
int
__clock_gettime (clockid_t clock_id, struct timespec *tp)
{
int ret;
struct __timespec64 tp64;
ret = __clock_gettime64 (clock_id, &tp64);
if (ret == 0)
{
if (! in_time_t_range (tp64.tv_sec))
{
__set_errno (EOVERFLOW);
return -1;
}
*tp = valid_timespec64_to_timespec (tp64);
}
return ret;
}
#endif
libc_hidden_def (__clock_gettime)
versioned_symbol (libc, __clock_gettime, clock_gettime, GLIBC_2_17);
/* clock_gettime moved to libc in version 2.17;
old binaries may expect the symbol version it had in librt. */
#if SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_17)
strong_alias (__clock_gettime, __clock_gettime_2);
compat_symbol (libc, __clock_gettime_2, clock_gettime, GLIBC_2_2);
#endif