[v2,7/7] y2038: linux: Provide __ntp_gettimex64 implementation

This patch provides new __ntp_gettimex64 explicit 64 bit function for getting
time parameters via NTP interface.

The call to __adjtimex in __ntp_gettime64 function has been replaced with
direct call to __clock_adjtime64 syscall, to simplify the code.

Moreover, a 32 bit version - __ntp_gettimex has been refactored to internally
use __ntp_gettimex64.

The __ntp_gettimex is now supposed to be used on systems still supporting 32
bit time (__TIMESIZE != 64) - hence the necessary conversions between struct
ntptimeval and 64 bit struct __ntptimeval64.

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 __ntp_gettimex64 and __ntp_gettimex.
---
 sysdeps/unix/sysv/linux/include/sys/timex.h |  3 +++
 sysdeps/unix/sysv/linux/ntp_gettimex.c      | 24 ++++++++++++++++++---
 2 files changed, 24 insertions(+), 3 deletions(-)

On 08/05/2020 11:56, Lukasz Majewski wrote:
> This patch provides new __ntp_gettimex64 explicit 64 bit function for getting
> time parameters via NTP interface.
> 
> The call to __adjtimex in __ntp_gettime64 function has been replaced with
> direct call to __clock_adjtime64 syscall, to simplify the code.
> 
> Moreover, a 32 bit version - __ntp_gettimex has been refactored to internally
> use __ntp_gettimex64.
> 
> The __ntp_gettimex is now supposed to be used on systems still supporting 32
> bit time (__TIMESIZE != 64) - hence the necessary conversions between struct
> ntptimeval and 64 bit struct __ntptimeval64.
> 
> 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 __ntp_gettimex64 and __ntp_gettimex.

Ok with a doubt below.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

> ---
>  sysdeps/unix/sysv/linux/include/sys/timex.h |  3 +++
>  sysdeps/unix/sysv/linux/ntp_gettimex.c      | 24 ++++++++++++++++++---
>  2 files changed, 24 insertions(+), 3 deletions(-)
> 
> diff --git a/sysdeps/unix/sysv/linux/include/sys/timex.h b/sysdeps/unix/sysv/linux/include/sys/timex.h
> index ef53515803..335a38c3bd 100644
> --- a/sysdeps/unix/sysv/linux/include/sys/timex.h
> +++ b/sysdeps/unix/sysv/linux/include/sys/timex.h
> @@ -34,6 +34,7 @@ libc_hidden_proto (__adjtimex)
>  #   define ___adjtimex64 ___adjtimex
>  #   define __ntptimeval64 ntptimeval
>  #   define __ntp_gettime64 __ntp_gettime
> +#   define __ntp_gettimex64 __ntp_gettimex
>  #  else
>  
>  struct __timex64
> @@ -94,6 +95,8 @@ struct __ntptimeval64
>  };
>  extern int __ntp_gettime64 (struct __ntptimeval64 *ntv);
>  libc_hidden_proto (__ntp_gettime64)
> +extern int __ntp_gettimex64 (struct __ntptimeval64 *ntv);
> +libc_hidden_proto (__ntp_gettimex64)
>  
>  #  endif
>  
> diff --git a/sysdeps/unix/sysv/linux/ntp_gettimex.c b/sysdeps/unix/sysv/linux/ntp_gettimex.c
> index 0f26d4806e..7d0328c6ca 100644
> --- a/sysdeps/unix/sysv/linux/ntp_gettimex.c
> +++ b/sysdeps/unix/sysv/linux/ntp_gettimex.c
> @@ -15,6 +15,7 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>  
> +#include <time.h>
>  #include <sys/timex.h>
>  
>  #ifndef MOD_OFFSET
> @@ -23,13 +24,13 @@
>  
>  
>  int
> -ntp_gettimex (struct ntptimeval *ntv)
> +__ntp_gettimex64 (struct __ntptimeval64 *ntv)
>  {
> -  struct timex tntx;
> +  struct __timex64 tntx;
>    int result;
>  
>    tntx.modes = 0;
> -  result = __adjtimex (&tntx);
> +  result = __clock_adjtime64 (CLOCK_REALTIME, &tntx);
>    ntv->time = tntx.time;
>    ntv->maxerror = tntx.maxerror;
>    ntv->esterror = tntx.esterror;
> @@ -40,3 +41,20 @@ ntp_gettimex (struct ntptimeval *ntv)
>    ntv->__glibc_reserved4 = 0;
>    return result;
>  }

Ok. As for ntp_gettimex64, maybe add a comment stating that using 
CLOCK_REALTIME should not make the function fail with EINVAL, ENODEV, 
or EOPNOTSUPP.  I am not sure about EPERM in this situation, should 
we check for that and avoid seeting NTV in such situation?

> +
> +#if __TIMESIZE != 64
> +libc_hidden_def (__ntp_gettimex64)
> +
> +int
> +__ntp_gettimex (struct ntptimeval *ntv)
> +{
> +  struct __ntptimeval64 ntv64;
> +  int result;
> +
> +  result = __ntp_gettimex64 (&ntv64);
> +  *ntv = valid_ntptimeval64_to_ntptimeval (ntv64);
> +
> +  return result;
> +}
> +#endif
> +strong_alias (__ntp_gettimex, ntp_gettimex)
>