From cd85cc1b9fdde604087c258787179cabfa86268f Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Thu, 24 Apr 2025 12:24:22 -0700 Subject: [PROPOSED] Document IERS vs NIST leap second metadata * Makefile, NEWS: Mention this. * leapseconds.awk: Output comments explaining the difference between the IERS and NIST leap-seconds.list last-modified and expiration metadata. (Thanks to Judah Levine.) --- Makefile | 5 +++++ NEWS | 6 ++++++ leapseconds.awk | 11 +++++++++-- 3 files changed, 20 insertions(+), 2 deletions(-) diff --git a/Makefile b/Makefile index 42f5135f..99407112 100644 --- a/Makefile +++ b/Makefile @@ -464,6 +464,11 @@ leaplist_URI = \ https://hpiers.obspm.fr/iers/bul/bulc/ntp/leap-seconds.list # The file is generated by the IERS Earth Orientation Centre, in Paris. leaplist_TZ = Europe/Paris +# +# To fetch leap-seconds.list from NIST via a less-secure protocol +# and with less-volatile metadata, use these settings: +#leaplist_URI = ftp://ftp.boulder.nist.gov/pub/time/leap-seconds.list +#leaplist_TZ = America/Denver # The zic command and its arguments. diff --git a/NEWS b/NEWS index 7a05aeb9..779b654e 100644 --- a/NEWS +++ b/NEWS @@ -11,6 +11,12 @@ Unreleased, experimental changes reproducible timestamps. Formerly, only the contents of the compressed tarballs had reproducible timestamps. + Changes to commentary + + The leapseconds file contains commentary about the IERS and NIST + last-modified and expiration timestamps for leap second data. + (Thanks to Judah Levine.) + Release 2025b - 2025-03-22 13:40:46 -0700 diff --git a/leapseconds.awk b/leapseconds.awk index 15e85012..b9986164 100644 --- a/leapseconds.awk +++ b/leapseconds.awk @@ -23,7 +23,8 @@ BEGIN { print "# This file is generated automatically from the data in the public-domain" print "# NIST/IERS format leap-seconds.list file, which can be copied from" print "# " - print "# or, in a variant with different comments, from" + print "# or via a less-secure protocol and with different comments and" + print "# less volatile last-modified and expiration timestamps, from" print "# ." print "# For more about leap-seconds.list, please see" print "# The NTP Timescale and Leap Seconds" @@ -125,7 +126,13 @@ END { epoch_minus_NTP = ((1970 - 1900) * 365 + 17) * 24 * 60 * 60 print "" - print "# POSIX timestamps for the data in this file:" + print "# Here are POSIX timestamps for the data in this file." + print "# \"#updated\" gives the last time the leap seconds data changed" + print "# or, if this file was derived from the IERS leap-seconds.list," + print "# the last time that file changed in any way." + print "# \"#expires\" gives the first time this file might be wrong;" + print "# if this file was derived from the IERS leap-seconds.list," + print "# this is typically a bit less than one year after \"updated\"." if (updated) { sstamp_to_ymdhMs(updated, ss_NTP) printf "#updated %d (%.4d-%.2d-%.2d %.2d:%.2d:%.2d UTC)\n", \ -- 2.48.1