Re: [PATCH] remaining steps for time64 switchover

[Rich Felker <dalias@libc.org>]

On Sun, Oct 27, 2019 at 05:12:59PM -0300, Matias Fonzo wrote:
> Hello Laurent,
> 
> Can utmps work without s6?.  I mean, independently of the init
> system or distribution...

Laurent could answer in better detail, but as a quick answer, there's
no requirement from having s6 installed that you use it as your init
system.

Rich


> El 2019-10-27 05:32, Laurent Bercot escribió:
> >>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