[PATCH v6 2/5] linux: Use long time_t __getitimer/__setitimer

[Alistair Francis]

On Mon, Mar 30, 2020 at 7:49 AM Adhemerval Zanella via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
>
>
> On 29/03/2020 19:19, Stepan Golosunov wrote:
> > 29.03.2020 в 11:17:17 -0700 Alistair Francis написал:
> >> On Sun, Mar 29, 2020 at 2:59 AM Stepan Golosunov <stepan@golosunov.pp.ru> wrote:
> >>>
> >>> 28.03.2020 в 08:22:46 -0700 Alistair Francis написал:
> >>>> --- /dev/null
> >>>> +++ b/sysdeps/unix/sysv/linux/getitimer.c
> >>>
> >>>> +int
> >>>> +__getitimer64 (__itimer_which_t which, struct __itimerval64 *curr_value)
> >>>> +{
> >>>> +#if __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64
> >>>> +  return INLINE_SYSCALL_CALL (getitimer, which, curr_value);
> >>>> +#else
> >>>> +  struct __itimerval32 curr_value_32;
> >>>> +
> >>>> +  if (INLINE_SYSCALL_CALL (getitimer, which, &curr_value_32) == -1)
> >>>> +    return -1;
> >>>> +
> >>>> +  curr_value->it_interval
> >>>> +    = valid_timeval32_to_timeval64 (curr_value_32.it_interval);
> >>>> +  curr_value->it_value
> >>>> +    = valid_timeval32_to_timeval64 (curr_value_32.it_value);
> >>>> +  return 0;
> >>>> +#endif
> >>>> +}
> >>>> +
> >>>> +#if __TIMESIZE != 64
> >>>> +libc_hidden_def (__getitimer64)
> >>>> +int
> >>>> +__getitimer (__itimer_which_t which, struct itimerval *curr_value)
> >>>> +{
> >>>> +  struct __itimerval64 val64;
> >>>> +
> >>>> +  val64.it_interval
> >>>> +    = valid_timeval_to_timeval64 (curr_value->it_interval);
> >>>> +  val64.it_value
> >>>> +    = valid_timeval_to_timeval64 (curr_value->it_value);
> >>>> +
> >>>> +  return __getitimer64 (which, &val64);
> >>>> +}
> >>>> +#endif
> >>>> +weak_alias (__getitimer, getitimer)
> >>>
> >>> __getitimer treats curr_value as input-only variable, while it's an
> >>> output-only one in __getitimer64.  This won't work.
> >>
> >> I'm not sure what you mean here, can you please elaborate?
> >
> > __getitimer (…, &curr_value) will never write to curr_value (or do
> > anything useful with it at all); while
> > __getitimer64 (…, &curr_value) will write to curr_value as expected.
> >
> > Conversion in __getitimer shold be in opposite direction and after
> > __getitimer64 call.
> >
>
> Indeed, it should be:
>
>   int
>   __getitimer64 (__itimer_which_t which, struct __itimerval64 *curr_value)
>   {
>     [...]
>   }
>
>   #if __TIMESIZE != 64
>   libc_hidden_def (__getitimer64)
>
>   int
>   __getitimer (__itimer_which_t which, struct itimerval *curr_value)
>   {
>     struct __itimerval64 val64;
>     if (__getitimer64 (which, &val64) != 0)
>       return -1;
>
>     curr_value->it_interval
>       = valid_timeval64_to_timeval (val64->it_interval);
>     curr_value->it_value
>       = valid_timeval64_to_timeval (val64->it_value);
>
>     return 0;
>   }
>   #endif

I changed it to this (which is very similar to above). Good catch on that.

#if __TIMESIZE != 64
libc_hidden_def (__getitimer64)
int
__getitimer (__itimer_which_t which, struct itimerval *curr_value)
{
  struct __itimerval64 val64;
  int ret = __getitimer64 (which, &val64);

  if (ret == 0 && curr_value)
    {
      curr_value->it_interval
        = valid_timeval64_to_timeval (val64.it_interval);
      curr_value->it_value
        = valid_timeval64_to_timeval (val64.it_value);
    }

  return ret;
}

Alistair