From nobody Sat Feb 25 17:02:38 2023 X-Original-To: freebsd-current@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4PPCk90fb0z3tdYX; Sat, 25 Feb 2023 17:02:41 +0000 (UTC) (envelope-from fbsd@www.zefox.net) Received: from www.zefox.net (www.zefox.net [50.1.20.27]) (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-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "www.zefox.com", Issuer "www.zefox.com" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4PPCk85nzJz3lsx; Sat, 25 Feb 2023 17:02:40 +0000 (UTC) (envelope-from fbsd@www.zefox.net) Authentication-Results: mx1.freebsd.org; none Received: from www.zefox.net (localhost [127.0.0.1]) by www.zefox.net (8.17.1/8.15.2) with ESMTPS id 31PH2dXd011245 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Sat, 25 Feb 2023 09:02:39 -0800 (PST) (envelope-from fbsd@www.zefox.net) Received: (from fbsd@localhost) by www.zefox.net (8.17.1/8.15.2/Submit) id 31PH2ckB011244; Sat, 25 Feb 2023 09:02:38 -0800 (PST) (envelope-from fbsd) Date: Sat, 25 Feb 2023 09:02:38 -0800 From: bob prohaska To: Mike Karels Cc: freebsd-arm@freebsd.org, freebsd-current@freebsd.org Subject: Re: Timekeeping problem in /usr/src on new RPI aarch64 snapshot Message-ID: <20230225170238.GA11193@www.zefox.net> References: <20230224210502.GA8127@www.zefox.net> <1216867532.11893.1677280869319@localhost> <20230225161625.GB8127@www.zefox.net> <0BA0C9F7-5F85-4EBF-86BB-428730746592@karels.net> List-Id: Discussions about the use of FreeBSD-current List-Archive: https://lists.freebsd.org/archives/freebsd-current List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-current@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0BA0C9F7-5F85-4EBF-86BB-428730746592@karels.net> X-Rspamd-Queue-Id: 4PPCk85nzJz3lsx X-Spamd-Bar: ---- X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:7065, ipnet:50.1.16.0/20, country:US] X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-ThisMailContainsUnwantedMimeParts: N On Sat, Feb 25, 2023 at 10:33:23AM -0600, Mike Karels wrote: > On 25 Feb 2023, at 10:16, bob prohaska wrote: > > > On Sat, Feb 25, 2023 at 12:21:09AM +0100, Ronald Klop wrote: > >> > >> UFS stores the current timestamp in the superblock of the FS on clean > >> shutdown/unmount. On boot it reads the time from the timestamp in the > >> superblock of the root FS. Of coarse this timestamp is behind for the > >> duration that the machine was off or rebooting so you need to adjust that > >> using ntp. For ZFS root you can use the fakertc port to do something > >> similar. > >> > >> > > Mark Millard points out: > > /etc/localtime Current zoneinfo file, see tzsetup(8) and zic(8). > > > > /etc/wall_cmos_clock Empty file. Its presence indicates that the > > machine's CMOS clock is set to local time, while > > its absence indicates a UTC CMOS clock. > > > > Since there is no /etc/wall_cmos_clock on the newly-installed filesystem > > it appears the superblock timestamp is then interpreted as UTC when a Pi > > boots, using whatever happens to be set in /etc/localtime. My confusion > > is reduced somewhat. On first boot, what is the state of /etc/localtime? > > > > I've neglected to run tzsetup immediately on many previous installations > > and not noticed any complaints about mis-set clocks in buildworld. Is this > > new behavior? > > /etc/localtime is used in formatting dates (e.g. for ls), but is not > involved in storage of timestamps. Timestamps on files, system time, etc, > are all in UTC. So the system should act normally if there is no > /etc/localtime, and after one is added. Does formatting include calculating offsets from UTC for display? On at least a couple of installs I've observed date reporting UTC time. After running tzsetup, set to PST, date then reported the same numerical time with a PST time zone. This happened very early in an installation lifecycle and seemed to just "go away" after a few reboots, though I never paid close attention since it caused no complaints. Thanks for replying! bob prohaska