[PATCH v2] y2038: linux: Provide __timespec_get64 implementation

[Adhemerval Zanella]

On 25/01/2020 17:38, Lukasz Majewski wrote:
> This patch provides new instance of Linux specific timespec_get.c file placed
> in ./sysdeps/unix/sysv/linux/.
> 
> When compared to this file version from ./time directory, it provides
> __timespec_get64 explicit 64 bit function for getting 64 bit time in the
> struct __timespec64 (for compilation using C11 standard).
> Moreover, a 32 bit version - __timespec_get internally uses
> __timespec_get64.
> 
> The __timespec_get is now supposed to be used on systems still supporting 32
> bit time (__TIMESIZE != 64) - hence the necessary conversion to 32 bit struct
> timespec.
> 
> Internally the timespec_get uses __clock_gettime64. This patch is necessary
> for having architectures with __WORDSIZE == 32 Y2038 safe.
> 
> 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 proper usage of both __timespec_get64 and __timespec_get.

LGTM, thanks.

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

> 
> ---
> Changes for v2:
> 
> - The conversion to support 64 bit time for timespec_get() has been moved
>   from ./time/timespec_get.c to sysdeps/unix/sysv/linux/timespec_get.c
>   (as suggested by Adhemerval) to avoid the need to create __clock_gettime64()
>   method for HURD (as 64 bit time support for machines with __WORDSIZE=32
>   and __TIMESIZE=32 is now developed solely for Linux).
> ---
>  include/time.h                         |  3 ++
>  sysdeps/unix/sysv/linux/timespec_get.c | 59 ++++++++++++++++++++++++++
>  2 files changed, 62 insertions(+)
>  create mode 100644 sysdeps/unix/sysv/linux/timespec_get.c
> 
> diff --git a/include/time.h b/include/time.h
> index 558923274a..047f431a1a 100644
> --- a/include/time.h
> +++ b/include/time.h
> @@ -254,6 +254,7 @@ extern double __difftime (time_t time1, time_t time0);
>  #if __TIMESIZE == 64
>  # define __clock_nanosleep_time64 __clock_nanosleep
>  # define __clock_gettime64 __clock_gettime
> +# define __timespec_get64 __timespec_get
>  #else
>  extern int __clock_nanosleep_time64 (clockid_t clock_id,
>                                       int flags, const struct __timespec64 *req,

Ok.

> @@ -261,6 +262,8 @@ extern int __clock_nanosleep_time64 (clockid_t clock_id,
>  libc_hidden_proto (__clock_nanosleep_time64)
>  extern int __clock_gettime64 (clockid_t clock_id, struct __timespec64 *tp);
>  libc_hidden_proto (__clock_gettime64)
> +extern int __timespec_get64 (struct __timespec64 *ts, int base);
> +libc_hidden_proto (__timespec_get64)
>  #endif
>  
>  /* Use in the clock_* functions.  Size of the field representing the

Ok.

> diff --git a/sysdeps/unix/sysv/linux/timespec_get.c b/sysdeps/unix/sysv/linux/timespec_get.c
> new file mode 100644
> index 0000000000..7e634f9dac
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/timespec_get.c
> @@ -0,0 +1,59 @@
> +/* timespec_get -- get system time - Linux version supporting 64 bit time.
> +   Copyright (C) 2020 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.
> +
> +   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 <time.h>
> +#include <errno.h>
> +
> +/* Set TS to calendar time based in time base BASE.  */
> +int
> +__timespec_get64 (struct __timespec64 *ts, int base)
> +{
> +  if (base == TIME_UTC)
> +    {
> +      __clock_gettime64 (CLOCK_REALTIME, ts);
> +      return base;
> +    }
> +  return 0;
> +}

Ok.

> +
> +#if __TIMESIZE != 64
> +libc_hidden_def (__timespec_get64)
> +
> +int
> +__timespec_get (struct timespec *ts, int base)
> +{
> +  int ret;
> +  struct __timespec64 tp64;
> +
> +  ret = __timespec_get64 (&tp64, base);
> +
> +  if (ret == TIME_UTC)
> +    {
> +      if (! in_time_t_range (tp64.tv_sec))
> +        {
> +          __set_errno (EOVERFLOW);
> +          return 0;
> +        }
> +
> +      *ts = valid_timespec64_to_timespec (tp64);
> +    }
> +
> +  return ret;
> +}
> +#endif
> +strong_alias (__timespec_get, timespec_get);
> 

Ok.