Re: [RFC v2 03/20] y2038: linux: Provide __clock_settime64 implementation

[Arnd Bergmann <arnd at arndb dot de>]

On Thu, Jun 27, 2019 at 6:17 PM Lukasz Majewski <lukma@denx.de> wrote:

> >
> > Ok, so you redirect both __clock_settime64 to __clock_settime
> > and __NR_settime64 to __NR_settime, in order to get back to the
> > same definition that you have today on 64-bit.
> >
> > Sorry for taking so long to understand that.
>
> Not only you had a hard time to understand it.

Here is how I had imagined it would be done in a way that I find
easier to understand:

#if __WORDSIZE == 32 /* yes, all of them including rv32 and x32 */
__clock_settime64 (clockid_t clock_id, const struct __timespec64 *tp)
{
   int ret;

   /* Make sure the time cvalue is OK.  */
   if (tp->tv_nsec < 0 || tp->tv_nsec >= 1000000000)
    {
       __set_errno (EINVAL);
       return -1;
     }
#ifdef __NR_clock_settime64
 ret = INLINE_SYSCALL_CALL (clock_settime64, clock_id, tp);
#endif

#ifndef __ASSUME_TIME64_SYSCALLS
  if (ret == 0 || errno != ENOSYS)
    return ret;

  if (! in_time_t_range (tp->tv_sec))
    {
      __set_errno (EOVERFLOW);
      return -1;
    }

  struct timespec ts32;
  valid_timespec64_to_timespec (tp, &ts32);
  ret = INLINE_SYSCALL_CALL (clock_settime, clock_id, &ts32);
#endif

  return ret;
}
#endif

This should be functionally identical to what you have, but avoid
some of the complexity, especially once linux-5.1 becomes the
minimum version.

      Arnd