Re: [PATCH] remaining steps for time64 switchover

["Laurent Bercot" <ska-dietlibc@skarnet.org>]

>Or here. So, the story on utmpx: we can either
>
>1. match the current size on 32-bit archs, but move the timeval to
>    unused space at the end where a time64 version fits, or
>
>2. match the current size and layout of the 64-bit struct, making it
>    possible to share records between 32- and 64-bit processes on the
>    same machine.
>
>Keep in mind that this struct is not used anywhere in libc presently,
>but normally it's used as a format for on-disk records.
>
>I'm kinda leaning towards option 2, but being that I don't use (and
>hate) utmp, I'd rather hear opinions from people who do use it. Either
>way time fields in existing data will break, so it's a question of
>whether that one-time breakage is already sufficient to go a bit
>further and get 32/64 compat afterwards.

I don't use the libc's utmpx, but I maintain utmps, which is a secure 
implementation of utmp, including the definition of struct utmpx.
I haven't been following the time64 thing closely. The current struct
utmpx definition includes a struct timeval. Will it need to change,
or will musl's struct timeval change be enough and naturally propagate
so the struct utmpx will become time64-compatible?

On-disk data is not a problem. On the distro that I know uses utmps
(Adélie), the utmp/wtmp records, by design, do not survive a reboot,
so a reboot will fix everything - and will be mandatory anyway on
arches where the musl ABI changes.

I'm not aware of any distribution that uses musl, doesn't use utmps,
and still keeps on-disk utmpx records.

--
Laurent