diff --git a/libc/tools/zoneinfo/generate b/libc/tools/zoneinfo/generate
index 3e21d0b9f..2059abd15 100755
--- a/libc/tools/zoneinfo/generate
+++ b/libc/tools/zoneinfo/generate
@@ -1,82 +1,131 @@
-#!/bin/bash
+#!/usr/bin/python
 # Run with no arguments from any directory, with no special setup required.
 
-# Abort if any command returns an error exit status, or if an undefined
-# variable is used.
-set -e
-set -u
+import ftplib
+import hashlib
+import os
+import re
+import shutil
+import string
+import subprocess
+import sys
+import tarfile
+import tempfile
 
-echo "Looking for bionic..."
-bionic_dir=$(cd $(dirname $0)/../../.. && pwd)
-bionic_zoneinfo_dir=$bionic_dir/libc/zoneinfo
-bionic_zoneinfo_tools_dir=$bionic_dir/libc/tools/zoneinfo
-if [[ ! -d "$bionic_zoneinfo_dir" || ! -d "$bionic_zoneinfo_tools_dir" ]]; then
-  echo "Can't find bionic's zoneinfo directories!"
-  exit 1
-fi
+# Find the bionic directory, searching upward from this script.
+bionic_libc_tools_zoneinfo_dir = os.path.realpath(os.path.dirname(sys.argv[0]))
+bionic_libc_tools_dir = os.path.dirname(bionic_libc_tools_zoneinfo_dir)
+bionic_libc_dir = os.path.dirname(bionic_libc_tools_dir)
+bionic_dir = os.path.dirname(bionic_libc_dir)
+bionic_libc_zoneinfo_dir = '%s/libc/zoneinfo' % bionic_dir
+if not os.path.isdir(bionic_libc_tools_zoneinfo_dir) or not os.path.isdir(bionic_libc_zoneinfo_dir):
+  print "Couldn't find bionic/libc/tools/zoneinfo!"
+  sys.exit(1)
+print 'Found bionic in %s...' % bionic_dir
+
+
+regions = ['africa', 'antarctica', 'asia', 'australasia', 'backward', 'etcetera', 'europe', 'factory', 'northamerica', 'southamerica']
+
+
+def current_tzdata_version():
+  return open('%s/zoneinfo.version' % bionic_libc_zoneinfo_dir).readline().rstrip('\n')
+
+
+def md5_file(filename):
+  md5 = hashlib.md5()
+  f = open(filename, 'rb')
+  while True:
+    data = f.read(8192)
+    if not data:
+      break
+    md5.update(data)
+  return md5.hexdigest()
+
+
+def upgrade_to(ftp, filename):
+  version = re.search('tzdata(.+)\.tar\.gz', filename).group(1)
+
+  # Switch to a temporary directory.
+  tmp_dir = tempfile.mkdtemp('-tzdata')
+  os.chdir(tmp_dir)
+  print 'Created temporary directory "%s"...' % tmp_dir
+
+  print 'Downloading %s...' % filename
+  ftp.retrbinary('RETR %s' % filename, open(filename, 'wb').write)
+  print 'MD5: %s' % md5_file(filename)
+
+  print 'Extracting...'
+  os.mkdir('extracted')
+  tar = tarfile.open(filename, 'r')
+  tar.extractall('extracted')
+
+  print 'Calling zic(1)...'
+  os.mkdir('data')
+  for region in regions:
+    if region != 'backward':
+      subprocess.check_call(['zic', '-d', 'data', 'extracted/%s' % region])
+
+  # Collect the data ZoneCompactor needs.
+  links = []
+  zones = []
+  for region in regions:
+    for line in open('extracted/%s' % region).readlines():
+      fields = string.split(line)
+      if len(fields) == 0:
+        continue
+      elif fields[0] == 'Link':
+        links.append('%s %s %s\n' % (fields[0], fields[1], fields[2]))
+        zones.append(fields[2])
+      elif fields[0] == 'Zone':
+        zones.append(fields[1])
+  zones.sort()
+
+  # Write it into the "setup" file.
+  setup = open('setup', 'w')
+  for link in links:
+    setup.write(link)
+  for zone in zones:
+    setup.write('%s\n' % zone)
+  setup.close()
+
+  print 'Calling ZoneCompactor...'
+  subprocess.check_call(['javac', '-d', '.',
+                         '%s/ZoneCompactor.java' % bionic_libc_tools_zoneinfo_dir,
+                         '%s/ZoneInfo.java' % bionic_libc_tools_zoneinfo_dir])
+  subprocess.check_call(['java', 'ZoneCompactor', 'setup', 'data'])
+
+  print 'Updating bionic from %s to %s...' % (current_tzdata_version(), version)
+  # Move the .dat and .idx files...
+  os.remove('%s/zoneinfo.dat' % bionic_libc_zoneinfo_dir)
+  shutil.move('zoneinfo.dat', bionic_libc_zoneinfo_dir)
+  os.remove('%s/zoneinfo.idx' % bionic_libc_zoneinfo_dir)
+  shutil.move('zoneinfo.idx', bionic_libc_zoneinfo_dir)
+  # Write the .version file...
+  zoneinfo_version = open('%s/zoneinfo.version' % bionic_libc_zoneinfo_dir, 'wb+')
+  zoneinfo_version.write('%s\n' % version)
+  zoneinfo_version.close()
 
-echo "Switching to temporary directory..."
-temp_dir=`mktemp -d`
-cd $temp_dir
-trap "rm -rf $temp_dir; exit" INT TERM EXIT
 
 # URL from "Sources for Time Zone and Daylight Saving Time Data"
 # http://www.twinsun.com/tz/tz-link.htm
-echo "Looking for new tzdata..."
-wget -N --no-verbose 'ftp://munnari.oz.au/pub/tzdata*.tar.gz'
-zoneinfo_version_file=$bionic_zoneinfo_dir/zoneinfo.version
-if [ -f "$zoneinfo_version_file" ]; then
-  current_version=tzdata`sed s/\n// < $zoneinfo_version_file`
-else
-  current_version=missing
-fi
-latest_archive=`ls -r -v tzdata*.tar.gz | head -n1`
-latest_version=`basename $latest_archive .tar.gz`
-if [ "$current_version" == "$latest_version" ]; then
-  echo "You already have the latest tzdata ($latest_version)!"
-  exit 1
-fi
 
-md5_sum=`md5sum $latest_archive`
-echo "MD5: $md5_sum"
+print 'Looking for new tzdata...'
+ftp = ftplib.FTP('ftp.iana.org')
+ftp.login()
+ftp.cwd('tz/releases')
+tzdata_filenames = []
+for filename in ftp.nlst():
+  if filename.startswith('tzdata20'):
+    tzdata_filenames.append(filename)
+tzdata_filenames.sort()
 
-echo "Extracting $latest_version..."
-mkdir $latest_version
-tar -C $latest_version -zxf $latest_archive
+# If you're several releases behind, we'll walk you through the upgrades one by one.
+current_version = current_tzdata_version()
+current_filename = 'tzdata%s.tar.gz' % current_version
+for filename in tzdata_filenames:
+  if filename > current_filename:
+    upgrade_to(ftp, filename)
+    sys.exit(0)
 
-echo "Compiling $latest_version..."
-mkdir data
-for i in \
-    africa \
-    antarctica \
-    asia \
-    australasia \
-    etcetera \
-    europe \
-    factory \
-    northamerica \
-    solar87 \
-    solar88 \
-    solar89 \
-    southamerica
-do
-    zic -d data $latest_version/$i
-done
-
-echo "Compacting $latest_version..."
-(
-    cat $latest_version/* | grep '^Link' | awk '{print $1, $2, $3}'
-    (
-        cat $latest_version/* | grep '^Zone' | awk '{print $2}'
-        cat $latest_version/* | grep '^Link' | awk '{print $3}'
-    ) | LC_ALL="C" sort
-) | grep -v Riyadh8 > setup
-
-javac -d . \
-    $bionic_zoneinfo_tools_dir/ZoneCompactor.java \
-    $bionic_zoneinfo_tools_dir/ZoneInfo.java
-java ZoneCompactor setup data
-
-echo "Updating bionic to $latest_version..."
-mv zoneinfo.dat zoneinfo.idx $bionic_zoneinfo_dir
-echo $latest_version | sed 's/tzdata//' > $bionic_zoneinfo_dir/zoneinfo.version
+print 'You already have the latest tzdata (%s)!' % current_version
+sys.exit(0)
diff --git a/libc/zoneinfo/zoneinfo.dat b/libc/zoneinfo/zoneinfo.dat
index cc1cb389d..779925595 100644
Binary files a/libc/zoneinfo/zoneinfo.dat and b/libc/zoneinfo/zoneinfo.dat differ
diff --git a/libc/zoneinfo/zoneinfo.idx b/libc/zoneinfo/zoneinfo.idx
index 0483c285f..507ae7a38 100644
Binary files a/libc/zoneinfo/zoneinfo.idx and b/libc/zoneinfo/zoneinfo.idx differ
diff --git a/libc/zoneinfo/zoneinfo.version b/libc/zoneinfo/zoneinfo.version
index 9412b94ca..e60676198 100644
--- a/libc/zoneinfo/zoneinfo.version
+++ b/libc/zoneinfo/zoneinfo.version
@@ -1 +1 @@
-2012c
+2012d