Date: Thu, 3 Dec 2020 12:46:04 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: Cy Schubert <Cy.Schubert@cschubert.com>, freebsd-arch@freebsd.org Subject: Re: struct timex and Linux adjtimex() Message-ID: <X8jB7CYRtt8ukdd5@kib.kiev.ua> In-Reply-To: <60612.1606991186@critter.freebsd.dk> References: <202012030523.0B35NsG7003810@slippy.cwsent.com> <X8i4UIzzH7vxkKvH@kib.kiev.ua> <60532.1606990671@critter.freebsd.dk> <X8i715mJUphnxXEo@kib.kiev.ua> <60612.1606991186@critter.freebsd.dk>
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On Thu, Dec 03, 2020 at 10:26:26AM +0000, Poul-Henning Kamp wrote: > -------- > Konstantin Belousov writes: > > On Thu, Dec 03, 2020 at 10:17:51AM +0000, Poul-Henning Kamp wrote: > > > -------- > > > Konstantin Belousov writes: > > > > > > > 1. Implement new syscall, which would take extended struct timex. > > > > ntp_adjtimex() perhaps should be kept for backward compatibility. > > > > [It does not matter where struct timeval is placed in the updated > > > > struct timex, see below]. > > > > > > That would break all ports with timekeeping software. > > Why ? > > Last I looked they all had "#ifdef FreeBSD use ntp_adjtim()", so if > you rename it to ntp_adjtimex() you break them. > > I see no problem having a #define to alias timex() to ntp_adjtime(), > but I doubt it would make life easier for anybody. (I think we used > to have that and it got GC'ed.) > > *If* we want to do this, the right way is to extend struct timex and > let ntpadjtime(2) handle the new modes. I do not propose to rename anything, the new syscall should be called ntp_adjtime, as it is now. Current (old) syscall, that takes current (non-extended) struct timex, would be kept versioned at FBSD_1.0. New syscall should come at FBSD_1.6 version and take new structure, still called struct timex. All existing sources should start using new syscall by recompile. If we provide ntp_adjtime@FBSD_1.0 AKA syscall slot 176, old binaries would continue working, and doing this is very easy, so I do not see why not.
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