[PATCH 06/10] y2038: linux: Provide __adjtime64 implementation

[Alistair Francis]

On Sun, Apr 26, 2020 at 6:31 AM Lukasz Majewski <lukma@denx.de> wrote:
>
> This patch provides new __adjtime64 explicit 64 bit function for adjusting
> Linux kernel clock.
>
> Internally, the __clock_adjtime64 syscall is used instead of __adjtimex. This
> patch is necessary for having architectures with __WORDSIZE == 32 Y2038 safe.
>
> Moreover, a 32 bit version - __adjtime has been refactored to internally use
> __adjtime64.
>
> The __adjtime is now supposed to be used on systems still supporting 32
> bit time (__TIMESIZE != 64) - hence the necessary conversions between struct
> timeval and 64 bit struct __timeval64.
>
>
> Build tests:
> ./src/scripts/build-many-glibcs.py glibcs
>
> Run-time tests:
> - Run specific tests on ARM/x86 32bit systems (qemu):
>   https://github.com/lmajewski/meta-y2038 and run tests:
>   https://github.com/lmajewski/y2038-tests/commits/master
>
> Above tests were performed with Y2038 redirection applied as well as without to
> test the proper usage of both __adjtime64 and __adjtime.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  include/sys/time.h                |  9 +++++++++
>  sysdeps/unix/sysv/linux/adjtime.c | 26 ++++++++++++++++++++++----
>  2 files changed, 31 insertions(+), 4 deletions(-)
>
> diff --git a/include/sys/time.h b/include/sys/time.h
> index 8153d75033..567e4b7562 100644
> --- a/include/sys/time.h
> +++ b/include/sys/time.h
> @@ -26,6 +26,15 @@ extern int __settimezone (const struct timezone *__tz)
>         attribute_hidden;
>  extern int __adjtime (const struct timeval *__delta,
>                       struct timeval *__olddelta);
> +
> +#  include <struct___timeval64.h>
> +#  if __TIMESIZE == 64
> +#   define __adjtime64 __adjtime
> +#  else
> +extern int __adjtime64 (const struct __timeval64 *itv,
> +                        struct __timeval64 *otv);
> +libc_hidden_proto (__adjtime64)
> +#  endif
>  extern int __getitimer (enum __itimer_which __which,
>                         struct itimerval *__value);
>  extern int __setitimer (enum __itimer_which __which,
> diff --git a/sysdeps/unix/sysv/linux/adjtime.c b/sysdeps/unix/sysv/linux/adjtime.c
> index c142f4f6ea..f7ec24b43a 100644
> --- a/sysdeps/unix/sysv/linux/adjtime.c
> +++ b/sysdeps/unix/sysv/linux/adjtime.c
> @@ -24,13 +24,13 @@
>  #define MIN_SEC        (INT_MIN / 1000000L + 2)
>
>  int
> -__adjtime (const struct timeval *itv, struct timeval *otv)
> +__adjtime64 (const struct __timeval64 *itv, struct __timeval64 *otv)
>  {
> -  struct timex tntx;
> +  struct __timex64 tntx;
>
>    if (itv)
>      {
> -      struct timeval tmp;
> +      struct __timeval64 tmp;
>
>        /* We will do some check here. */
>        tmp.tv_sec = itv->tv_sec + itv->tv_usec / 1000000L;
> @@ -43,7 +43,7 @@ __adjtime (const struct timeval *itv, struct timeval *otv)
>    else
>      tntx.modes = ADJ_OFFSET_SS_READ;
>
> -  if (__glibc_unlikely (__adjtimex (&tntx) < 0))
> +  if (__glibc_unlikely (__clock_adjtime64 (CLOCK_REALTIME, &tntx) < 0))
>      return -1;
>
>    if (otv)
> @@ -62,6 +62,24 @@ __adjtime (const struct timeval *itv, struct timeval *otv)
>    return 0;
>  }
>
> +#if __TIMESIZE != 64
> +libc_hidden_def (__adjtime64)
> +
> +int
> +__adjtime (const struct timeval *itv, struct timeval *otv)
> +{
> +  struct __timeval64 itv64, otv64;
> +  int retval;
> +
> +  itv64 = valid_timeval_to_timeval64 (*itv);
> +  retval = __adjtime64 (&itv64, otv != NULL ? &otv64 : NULL);
> +  if (otv != NULL)
> +         *otv = valid_timeval64_to_timeval (otv64);
> +
> +  return retval;
> +}
> +#endif
> +
>  #ifdef VERSION_adjtime
>  weak_alias (__adjtime, __wadjtime);
>  default_symbol_version (__wadjtime, adjtime, VERSION_adjtime);
> --
> 2.20.1
>