From owner-freebsd-arch@freebsd.org Thu Dec 3 20:06:11 2020 Return-Path: Delivered-To: freebsd-arch@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 7B53F4AE7BB for ; Thu, 3 Dec 2020 20:06:11 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4Cn6KZ1MW8z4gvL for ; Thu, 3 Dec 2020 20:06:09 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.16.1/8.16.1) with ESMTPS id 0B3K5sm9076185 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Thu, 3 Dec 2020 22:05:57 +0200 (EET) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua 0B3K5sm9076185 Received: (from kostik@localhost) by tom.home (8.16.1/8.16.1/Submit) id 0B3K5rhw076184; Thu, 3 Dec 2020 22:05:53 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Thu, 3 Dec 2020 22:05:53 +0200 From: Konstantin Belousov To: Cy Schubert Cc: Poul-Henning Kamp , freebsd-arch@freebsd.org Subject: Re: struct timex and Linux adjtimex() Message-ID: References: <202012030523.0B35NsG7003810@slippy.cwsent.com> <60532.1606990671@critter.freebsd.dk> <60612.1606991186@critter.freebsd.dk> <202012031717.0B3HHalx003916@slippy.cwsent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <202012031717.0B3HHalx003916@slippy.cwsent.com> X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FROM, NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on tom.home X-Rspamd-Queue-Id: 4Cn6KZ1MW8z4gvL X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=gmail.com (policy=none); spf=softfail (mx1.freebsd.org: 2001:470:d5e7:1::1 is neither permitted nor denied by domain of kostikbel@gmail.com) smtp.mailfrom=kostikbel@gmail.com X-Spamd-Result: default: False [-2.91 / 15.00]; RCVD_TLS_ALL(0.00)[]; ARC_NA(0.00)[]; DMARC_POLICY_SOFTFAIL(0.10)[gmail.com : No valid SPF, No valid DKIM,none]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; FREEMAIL_FROM(0.00)[gmail.com]; NEURAL_HAM_LONG(-1.00)[-1.000]; MIME_GOOD(-0.10)[text/plain]; HAS_XAW(0.00)[]; RBL_DBL_DONT_QUERY_IPS(0.00)[2001:470:d5e7:1::1:from]; TO_DN_SOME(0.00)[]; R_SPF_SOFTFAIL(0.00)[~all]; SPAMHAUS_ZRD(0.00)[2001:470:d5e7:1::1:from:127.0.2.255]; TO_MATCH_ENVRCPT_SOME(0.00)[]; NEURAL_HAM_SHORT(-0.91)[-0.913]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:6939, ipnet:2001:470::/32, country:US]; MIME_TRACE(0.00)[0:+]; MAILMAN_DEST(0.00)[freebsd-arch]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 03 Dec 2020 20:06:11 -0000 On Thu, Dec 03, 2020 at 09:17:36AM -0800, Cy Schubert wrote: > In message <60612.1606991186@critter.freebsd.dk>, "Poul-Henning Kamp" > writes: > > -------- > > 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. > > There was no discussion about renaming ntp_adjtime() to ntp_adjtimex(). > ntp_adjtime() would remain. A new adjtimex() would be added. As discussed, we should stay with ntp_adjtime(), it seems. Libc may provide adjtimex() as an alias if this makes some porting easier. BTW, I can code the syscall and compat layers, if this would make thinks easier for everybody. I can do the addition of the actual flag if you describe the semantic in more details. I see the description of ADJ_SETOFFSET in the Linux adjtimex(2) man page: ADJ_SETOFFSET (since Linux 2.6.39) Add buf.time to the current time. If buf.status includes the ADJ_NANO flag, then buf.time.tv_usec is interpreted as a nanosecond value; otherwise it is interpreted as microseconds. The value of buf.time is the sum of its two fields, but the field buf.time.tv_usec must always be nonnegative. The follow‐ ing example shows how to normalize a timeval with nanosecond resolution. while (buf.time.tv_usec < 0) { buf.time.tv_sec -= 1; buf.time.tv_usec += 1000000000; } I do not quite understand the context and internal meaning of the second paragraph, though. Kernel should not allow negative tv_usec as the input parameter, right ? > > > > > 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. > > > > -- > > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > > phk@FreeBSD.ORG | TCP/IP since RFC 956 > > FreeBSD committer | BSD since 4.3-tahoe > > Never attribute to malice what can adequately be explained by incompetence. > > > -- > Cheers, > Cy Schubert > FreeBSD UNIX: Web: https://FreeBSD.org > NTP: Web: https://nwtime.org > > The need of the many outweighs the greed of the few. >