Re: [RFC v6 03/23] time: Add a timeval with a long tv_sec and tv_usec

[Lukasz Majewski <lukma at denx dot de>]

Hi Alistair,

> On y2038 safe 32-bit systems the Linux kernel expects itimerval to
> use a 32-bit time_t, even though the other time_t's are 64-bit. To
> address this let's add a timeval_long
			   ^^^^^^^^^^^^^ - I'm not so seasoned glibc
			   developer, but I think that the _long suffix
			   is a bit misleading.

	Maybe it would be more readable to name it as struct
	__timeval32 ? In that way one can see from the outset that we
	operate on 32 bit values.

	Community feedback is welcome :-)

> struct to be used internally.
> ---
>  include/time.h                   | 29 +++++++++++++++++++++++++++++
>  time/bits/types/struct_timeval.h |  8 ++++++++
>  2 files changed, 37 insertions(+)
> 
> diff --git a/include/time.h b/include/time.h
> index e5e8246eac..201342d1ca 100644
> --- a/include/time.h
> +++ b/include/time.h
> @@ -310,6 +310,35 @@ valid_timespec64_to_timeval (const struct
> __timespec64 ts64) return tv;
>  }
>  
> +/* Conversion functions for converting to/from __timeval_long
> +.  If the seconds field of a __timeval_long would
> +   overflow, they write { INT32_MAX, 999999 } to the output.  */
> +static inline struct timeval
> +valid_timeval_long_to_timeval64 (const struct __timeval_long tv)
> +{
> +  return (struct timeval) { tv.tv_sec, tv.tv_usec };
> +}
> +
> +static inline struct __timeval_long
> +valid_timeval64_to_timeval_long (const struct timeval tv64)
> +{
> +  if (__glibc_unlikely (tv64.tv_sec > (time_t) 2147483647))
> +    return (struct __timeval_long) { 2147483647, 999999};
> +  return (struct __timeval_long) { tv64.tv_sec, tv64.tv_usec };
> +}
> +
> +static inline struct timespec
> +valid_timeval_long_to_timespec (const struct __timeval_long tv)
> +{
> +  return (struct timespec) { tv.tv_sec, tv.tv_usec * 1000 };
> +}
> +
> +static inline struct __timeval_long
> +valid_timespec_to_timeval_long (const struct timespec ts)
> +{
> +  return (struct __timeval_long) { (time_t) ts.tv_sec, ts.tv_nsec /
> 1000 }; +}
> +
>  /* Check if a value is in the valid nanoseconds range. Return true if
>     it is, false otherwise.  */
>  static inline bool
> diff --git a/time/bits/types/struct_timeval.h
> b/time/bits/types/struct_timeval.h index 70394ce886..73697689cc 100644
> --- a/time/bits/types/struct_timeval.h
> +++ b/time/bits/types/struct_timeval.h
> @@ -10,4 +10,12 @@ struct timeval
>    __time_t tv_sec;		/* Seconds.  */
>    __suseconds_t tv_usec;	/* Microseconds.  */
>  };
> +
> +/* A version of 'struct timeval' with `long` time_t
> +   and suseconds_t.  */
> +struct __timeval_long
> +{
> +  long tv_sec;		/* Seconds.  */
> +  long tv_usec;		/* Microseconds.  */
> +};
>  #endif

Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de

Attachment: pgpMcfhJqBERh.pgp
Description: OpenPGP digital signature