4 files changed, 190 insertions, 0 deletions
diff --git a/lib/time/README b/lib/time/README
new file mode 100644
index 0000000..0de06df
--- /dev/null
+++ b/lib/time/README
@@ -0,0 +1,10 @@
+The zoneinfo.zip archive contains time zone files compiled using
+the code and data maintained as part of the IANA Time Zone Database.
+The IANA asserts that the database is in the public domain.
+
+For more information, see
+https://www.iana.org/time-zones
+ftp://ftp.iana.org/tz/code/tz-link.html
+https://datatracker.ietf.org/doc/html/rfc6557
+
+To rebuild the archive, read and run update.bash.
diff --git a/lib/time/mkzip.go b/lib/time/mkzip.go
new file mode 100644
index 0000000..3920b11
--- /dev/null
+++ b/lib/time/mkzip.go
@@ -0,0 +1,94 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build ignore
+
+// Mkzip writes a zoneinfo.zip with the content of the current directory
+// and its subdirectories, with no compression, suitable for package time.
+//
+// Usage:
+//
+//	go run ../../mkzip.go ../../zoneinfo.zip
+//
+// We use this program instead of 'zip -0 -r ../../zoneinfo.zip *' to get
+// a reproducible generator that does not depend on which version of the
+// external zip tool is used or the ordering of file names in a directory
+// or the current time.
+package main
+
+import (
+	"archive/zip"
+	"bytes"
+	"flag"
+	"fmt"
+	"hash/crc32"
+	"io/fs"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "usage: go run mkzip.go ../../zoneinfo.zip\n")
+	os.Exit(2)
+}
+
+func main() {
+	log.SetPrefix("mkzip: ")
+	log.SetFlags(0)
+	flag.Usage = usage
+	flag.Parse()
+	args := flag.Args()
+	if len(args) != 1 || !strings.HasSuffix(args[0], ".zip") {
+		usage()
+	}
+
+	var zb bytes.Buffer
+	zw := zip.NewWriter(&zb)
+	seen := make(map[string]bool)
+	err := filepath.WalkDir(".", func(path string, d fs.DirEntry, err error) error {
+		if d.IsDir() {
+			return nil
+		}
+		data, err := os.ReadFile(path)
+		if err != nil {
+			log.Fatal(err)
+		}
+		if strings.HasSuffix(path, ".zip") {
+			log.Fatalf("unexpected file during walk: %s", path)
+		}
+		name := filepath.ToSlash(path)
+		w, err := zw.CreateRaw(&zip.FileHeader{
+			Name:               name,
+			Method:             zip.Store,
+			CompressedSize64:   uint64(len(data)),
+			UncompressedSize64: uint64(len(data)),
+			CRC32:              crc32.ChecksumIEEE(data),
+		})
+		if err != nil {
+			log.Fatal(err)
+		}
+		if _, err := w.Write(data); err != nil {
+			log.Fatal(err)
+		}
+		seen[name] = true
+		return nil
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := zw.Close(); err != nil {
+		log.Fatal(err)
+	}
+	if len(seen) == 0 {
+		log.Fatalf("did not find any files to add")
+	}
+	if !seen["US/Eastern"] {
+		log.Fatalf("did not find US/Eastern to add")
+	}
+	if err := os.WriteFile(args[0], zb.Bytes(), 0666); err != nil {
+		log.Fatal(err)
+	}
+}
diff --git a/lib/time/update.bash b/lib/time/update.bash
new file mode 100755
index 0000000..e728500
--- /dev/null
+++ b/lib/time/update.bash
@@ -0,0 +1,86 @@
+#!/bin/bash
+# Copyright 2012 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+# This script rebuilds the time zone files using files
+# downloaded from the ICANN/IANA distribution.
+#
+# To prepare an update for a new Go release,
+# consult https://www.iana.org/time-zones for the latest versions,
+# update CODE and DATA below, and then run
+#
+#	./update.bash -commit
+#
+# That will prepare the files and create the commit.
+#
+# To review such a commit (as the reviewer), use:
+#
+#	git codereview change NNNNNN   # CL number
+#	cd lib/time
+#	./update.bash
+#
+# If it prints "No updates needed.", then the generated files
+# in the CL match the update.bash in the CL.
+
+# Versions to use.
+CODE=2023d
+DATA=2023d
+
+set -e
+
+cd $(dirname $0)
+rm -rf work
+mkdir work
+go build -o work/mkzip mkzip.go # build now for correct paths in build errors
+cd work
+mkdir zoneinfo
+curl -sS -L -O https://www.iana.org/time-zones/repository/releases/tzcode$CODE.tar.gz
+curl -sS -L -O https://www.iana.org/time-zones/repository/releases/tzdata$DATA.tar.gz
+tar xzf tzcode$CODE.tar.gz
+tar xzf tzdata$DATA.tar.gz
+
+if ! make CFLAGS=-DSTD_INSPIRED AWK=awk TZDIR=zoneinfo posix_only >make.out 2>&1; then
+	cat make.out
+	exit 2
+fi
+
+cd zoneinfo
+../mkzip ../../zoneinfo.zip
+cd ../..
+
+files="update.bash zoneinfo.zip"
+modified=true
+if git diff --quiet $files; then
+	modified=false
+fi
+
+if [ "$1" = "-work" ]; then
+	echo Left workspace behind in work/.
+	shift
+else
+	rm -rf work
+fi
+
+if ! $modified; then
+	echo No updates needed.
+	exit 0
+fi
+
+echo Updated for $CODE/$DATA: $files
+
+commitmsg="lib/time: update to $CODE/$DATA
+
+Commit generated by update.bash.
+
+For #22487.
+"
+
+if [ "$1" = "-commit" ]; then
+	echo "Creating commit. Run 'git reset HEAD^' to undo commit."
+	echo
+	git commit -m "$commitmsg" $files
+	echo
+	git log -n1 --stat
+	echo
+fi
diff --git a/lib/time/zoneinfo.zip b/lib/time/zoneinfo.zip
new file mode 100644
index 0000000..7cf689f
--- /dev/null
+++ b/lib/time/zoneinfo.zip