diff --git a/libc/tools/zoneinfo/ZoneCompactor.java b/libc/tools/zoneinfo/ZoneCompactor.java
new file mode 100644
index 0000000..b657748
--- /dev/null
+++ b/libc/tools/zoneinfo/ZoneCompactor.java
@@ -0,0 +1,166 @@
+
+import java.io.*;
+import java.util.*;
+
+// usage: java ZoneCompiler <setup file> <top-level directory>
+//
+// Compile a set of tzfile-formatted files into a single file plus
+// an index file.
+//
+// The compilation is controlled by a setup file, which is provided as a
+// command-line argument.  The setup file has the form:
+//
+// Link <toName> <fromName>
+// ...
+// <zone filename>
+// ...
+//
+// Note that the links must be declared prior to the zone names.  A
+// zone name is a filename relative to the source directory such as
+// 'GMT', 'Africa/Dakar', or 'America/Argentina/Jujuy'.
+//
+// Use the 'zic' command-line tool to convert from flat files
+// (e.g., 'africa', 'northamerica') into a suitable source directory
+// hierarchy for this tool (e.g., 'data/Africa/Abidjan').
+//
+// Example:
+//     zic -d data tz2007h
+//     javac ZoneCompactor.java
+//     java ZoneCompactor setup data
+//     <produces zoneinfo.dat and zoneinfo.idx>
+
+public class ZoneCompactor {
+
+    // Zone name synonyms
+    Map<String,String> links = new HashMap<String,String>();
+
+    // File starting bytes by zone name
+    Map<String,Integer> starts = new HashMap<String,Integer>();
+
+    // File lengths by zone name
+    Map<String,Integer> lengths = new HashMap<String,Integer>();
+
+    // Raw GMT offsets by zone name
+    Map<String,Integer> offsets = new HashMap<String,Integer>();
+    int start = 0;
+
+    // Maximum number of characters in a zone name, including '\0' terminator
+    private static final int MAXNAME = 40;
+
+    // Concatenate the contents of 'inFile' onto 'out'
+    // and return the contents as a byte array.
+    private static byte[] copyFile(File inFile, OutputStream out)
+        throws Exception {
+        byte[] ret = new byte[0];
+
+        InputStream in = new FileInputStream(inFile);
+        byte[] buf = new byte[8192];
+        while (true) {
+            int nbytes = in.read(buf);
+            if (nbytes == -1) {
+                break;
+            }
+            out.write(buf, 0, nbytes);
+
+            byte[] nret = new byte[ret.length + nbytes];
+            System.arraycopy(ret, 0, nret, 0, ret.length);
+            System.arraycopy(buf, 0, nret, ret.length, nbytes);
+            ret = nret;
+        }
+        out.flush();
+        return ret;
+    }
+    
+    // Write a 32-bit integer in network byte order
+    private void writeInt(OutputStream os, int x) throws IOException {
+        os.write((x >> 24) & 0xff);
+        os.write((x >> 16) & 0xff);
+        os.write((x >>  8) & 0xff);
+        os.write( x        & 0xff);
+    }
+
+    public ZoneCompactor(String setupFilename, String dirName)
+        throws Exception {
+        File zoneInfoFile = new File("zoneinfo.dat");
+        zoneInfoFile.delete();
+        OutputStream zoneInfo = new FileOutputStream(zoneInfoFile);
+
+        BufferedReader rdr = new BufferedReader(new FileReader(setupFilename));
+    
+        String s;
+        while ((s = rdr.readLine()) != null) {
+            s = s.trim();
+            if (s.startsWith("Link")) {
+                StringTokenizer st = new StringTokenizer(s);
+                st.nextToken();
+                String to = st.nextToken();
+                String from = st.nextToken();
+                links.put(from, to);
+            } else {
+                String link = links.get(s);
+                if (link == null) {
+                    File f = new File(dirName, s);
+                    long length = f.length();
+                    starts.put(s, new Integer(start));
+                    lengths.put(s, new Integer((int)length));
+
+                    start += length;
+                    byte[] data = copyFile(f, zoneInfo);
+
+                    TimeZone tz = ZoneInfo.make(s, data);
+                    int gmtOffset = tz.getRawOffset();
+                    offsets.put(s, new Integer(gmtOffset));
+                }
+            }
+        }
+        zoneInfo.close();
+
+        // Fill in fields for links
+        Iterator<String> iter = links.keySet().iterator();
+        while (iter.hasNext()) {
+            String from = iter.next();
+            String to = links.get(from);
+
+            starts.put(from, starts.get(to));
+            lengths.put(from, lengths.get(to));
+            offsets.put(from, offsets.get(to));
+        }
+
+        File idxFile = new File("zoneinfo.idx");
+        idxFile.delete();
+        FileOutputStream idx = new FileOutputStream(idxFile);
+
+        ArrayList<String> l = new ArrayList<String>();
+        l.addAll(starts.keySet());
+        Collections.sort(l);
+        Iterator<String> ziter = l.iterator();
+        while (ziter.hasNext()) {
+            String zname = ziter.next();
+            if (zname.length() >= MAXNAME) {
+                System.err.println("Error - zone filename exceeds " +
+                                   (MAXNAME - 1) + " characters!");
+            }
+
+            byte[] znameBuf = new byte[MAXNAME];
+            for (int i = 0; i < zname.length(); i++) {
+                znameBuf[i] = (byte)zname.charAt(i);
+            }
+            idx.write(znameBuf);
+            writeInt(idx, starts.get(zname).intValue());
+            writeInt(idx, lengths.get(zname).intValue());
+            writeInt(idx, offsets.get(zname).intValue());
+        }
+        idx.close();
+
+        // System.out.println("maxLength = " + maxLength);
+    }
+
+    public static void main(String[] args) throws Exception {
+        if (args.length != 2) {
+            System.err.println("usage: java ZoneCompactor <setup> <data dir>");
+            System.exit(0);
+        }
+        new ZoneCompactor(args[0], args[1]);
+    }
+
+}
diff --git a/libc/tools/zoneinfo/ZoneInfo.java b/libc/tools/zoneinfo/ZoneInfo.java
new file mode 100644
index 0000000..99507ae
--- /dev/null
+++ b/libc/tools/zoneinfo/ZoneInfo.java
@@ -0,0 +1,272 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Date;
+import java.util.TimeZone;
+
+/**
+ * Copied from ZoneInfo and ZoneInfoDB in dalvik.
+ * {@hide}
+ */
+public class ZoneInfo extends TimeZone {
+
+    private static final long MILLISECONDS_PER_DAY = 24 * 60 * 60 * 1000;
+    private static final long MILLISECONDS_PER_400_YEARS =
+        MILLISECONDS_PER_DAY * (400 * 365 + 100 - 3);
+
+    private static final long UNIX_OFFSET = 62167219200000L;
+
+    private static final int[] NORMAL = new int[] {
+        0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334,
+    };
+
+    private static final int[] LEAP = new int[] {
+        0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335,
+    };
+
+    private static String nullName(byte[] data, int where, int off) {
+        if (off < 0)
+            return null;
+
+        int end = where + off;
+        while (end < data.length && data[end] != '\0')
+            end++;
+
+        return new String(data, where + off, end - (where + off));
+    }
+
+    public static ZoneInfo make(String name, byte[] data) {
+        int ntransition = read4(data, 32);
+        int ngmtoff = read4(data, 36);
+        int base = 44;
+
+        int[] transitions = new int[ntransition];
+        for (int i = 0; i < ntransition; i++)
+            transitions[i] = read4(data, base + 4 * i);
+        base += 4 * ntransition;
+
+        byte[] type = new byte[ntransition];
+        for (int i = 0; i < ntransition; i++)
+            type[i] = data[base + i];
+        base += ntransition;
+
+        int[] gmtoff = new int[ngmtoff];
+        byte[] isdst = new byte[ngmtoff];
+        byte[] abbrev = new byte[ngmtoff];
+        for (int i = 0; i < ngmtoff; i++) {
+            gmtoff[i] = read4(data, base + 6 * i);
+            isdst[i] = data[base + 6 * i + 4];
+            abbrev[i] = data[base + 6 * i + 5];
+        }
+
+        base += 6 * ngmtoff;
+
+        return new ZoneInfo(name, transitions, type, gmtoff, isdst, abbrev, data, base);
+    }
+
+    private static int read4(byte[] data, int off) {
+        return ((data[off    ] & 0xFF) << 24) |
+               ((data[off + 1] & 0xFF) << 16) |
+               ((data[off + 2] & 0xFF) <<  8) |
+               ((data[off + 3] & 0xFF) <<  0);
+    }
+
+    /*package*/ ZoneInfo(String name, int[] transitions, byte[] type,
+                     int[] gmtoff, byte[] isdst, byte[] abbrev,
+                     byte[] data, int abbrevoff) {
+        mTransitions = transitions;
+        mTypes = type;
+        mGmtOffs = gmtoff;
+        mIsDsts = isdst;
+        mUseDst = false;
+        setID(name);
+
+        // Find the latest GMT and non-GMT offsets for their abbreviations
+
+        int lastdst;
+        for (lastdst = mTransitions.length - 1; lastdst >= 0; lastdst--) {
+            if (mIsDsts[mTypes[lastdst] & 0xFF] != 0)
+                break;
+        }
+
+        int laststd;
+        for (laststd = mTransitions.length - 1; laststd >= 0; laststd--) {
+            if (mIsDsts[mTypes[laststd] & 0xFF] == 0)
+                break;
+        }
+
+        if (lastdst >= 0) {
+            mDaylightName = nullName(data, abbrevoff,
+                                     abbrev[mTypes[lastdst] & 0xFF]);
+        }
+        if (laststd >= 0) {
+            mStandardName = nullName(data, abbrevoff,
+                                     abbrev[mTypes[laststd] & 0xFF]);
+        }
+
+        // Use the latest non-DST offset if any as the raw offset
+
+        if (laststd < 0) {
+            laststd = 0;
+        }
+
+        if (laststd >= mTypes.length) {
+            mRawOffset = mGmtOffs[0];
+        } else {
+            mRawOffset = mGmtOffs[mTypes[laststd] & 0xFF];
+        }
+
+        // Subtract the raw offset from all offsets so it can be changed
+        // and affect them too.
+        // Find whether there exist any observances of DST.
+
+        for (int i = 0; i < mGmtOffs.length; i++) {
+            mGmtOffs[i] -= mRawOffset;
+
+            if (mIsDsts[i] != 0) {
+                mUseDst = true;
+            }
+        }
+
+        mRawOffset *= 1000;
+    }
+
+    @Override
+    public int getOffset(@SuppressWarnings("unused") int era,
+        int year, int month, int day,
+        @SuppressWarnings("unused") int dayOfWeek,
+        int millis) {
+        // XXX This assumes Gregorian always; Calendar switches from
+        // Julian to Gregorian in 1582.  What calendar system are the
+        // arguments supposed to come from?
+
+        long calc = (year / 400) * MILLISECONDS_PER_400_YEARS;
+        year %= 400;
+
+        calc += year * (365 * MILLISECONDS_PER_DAY);
+        calc += ((year + 3) / 4) * MILLISECONDS_PER_DAY;
+
+        if (year > 0)
+            calc -= ((year - 1) / 100) * MILLISECONDS_PER_DAY;
+
+        boolean isLeap = (year == 0 || (year % 4 == 0 && year % 100 != 0));
+        int[] mlen = isLeap ? LEAP : NORMAL;
+
+        calc += mlen[month] * MILLISECONDS_PER_DAY;
+        calc += (day - 1) * MILLISECONDS_PER_DAY;
+        calc += millis;
+
+        calc -= mRawOffset;
+        calc -= UNIX_OFFSET;
+
+        return getOffset(calc);
+    }
+
+    @Override
+    public int getOffset(long when) {
+        int unix = (int) (when / 1000);
+        int trans = Arrays.binarySearch(mTransitions, unix);
+
+        if (trans == ~0) {
+            return mGmtOffs[0] * 1000 + mRawOffset;
+        }
+        if (trans < 0) {
+            trans = ~trans - 1;
+        }
+
+        return mGmtOffs[mTypes[trans] & 0xFF] * 1000 + mRawOffset;
+    }
+
+    @Override
+    public int getRawOffset() {
+        return mRawOffset;
+    }
+
+    @Override
+    public void setRawOffset(int off) {
+        mRawOffset = off;
+    }
+
+    @Override
+    public boolean inDaylightTime(Date when) {
+        int unix = (int) (when.getTime() / 1000);
+        int trans = Arrays.binarySearch(mTransitions, unix);
+
+        if (trans == ~0) {
+            return mIsDsts[0] != 0;
+        }
+        if (trans < 0) {
+            trans = ~trans - 1;
+        }
+
+        return mIsDsts[mTypes[trans] & 0xFF] != 0;
+    }
+
+    @Override
+    public boolean useDaylightTime() {
+        return mUseDst;
+    }
+
+    private int mRawOffset;
+    private int[] mTransitions;
+    private int[] mGmtOffs;
+    private byte[] mTypes;
+    private byte[] mIsDsts;
+    private boolean mUseDst;
+    private String mDaylightName;
+    private String mStandardName;
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (!(obj instanceof ZoneInfo)) {
+           return false;
+        }
+        ZoneInfo other = (ZoneInfo) obj;
+        return mUseDst == other.mUseDst
+                && (mDaylightName == null ? other.mDaylightName == null :
+                        mDaylightName.equals(other.mDaylightName))
+                && (mStandardName == null ? other.mStandardName == null :
+                        mStandardName.equals(other.mStandardName))
+                && mRawOffset == other.mRawOffset
+                // Arrays.equals returns true if both arrays are null
+                && Arrays.equals(mGmtOffs, other.mGmtOffs)
+                && Arrays.equals(mIsDsts, other.mIsDsts)
+                && Arrays.equals(mTypes, other.mTypes)
+                && Arrays.equals(mTransitions, other.mTransitions);
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((mDaylightName == null) ? 0 :
+                mDaylightName.hashCode());
+        result = prime * result + Arrays.hashCode(mGmtOffs);
+        result = prime * result + Arrays.hashCode(mIsDsts);
+        result = prime * result + mRawOffset;
+        result = prime * result + ((mStandardName == null) ? 0 :
+                mStandardName.hashCode());
+        result = prime * result + Arrays.hashCode(mTransitions);
+        result = prime * result + Arrays.hashCode(mTypes);
+        result = prime * result + (mUseDst ? 1231 : 1237);
+        return result;
+    }
+}
diff --git a/libc/tools/zoneinfo/generate b/libc/tools/zoneinfo/generate
new file mode 100755
index 0000000..5755e26
--- /dev/null
+++ b/libc/tools/zoneinfo/generate
@@ -0,0 +1,79 @@
+#!/bin/bash
+# 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
+
+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
+
+echo "Switching to temporary directory..."
+temp_dir=`mktemp -d`
+cd $temp_dir
+trap "rm -rf $temp_dir; exit" INT TERM EXIT
+
+# URL from "Sources for Time Zone and Daylight Saving Time Data"
+# http://www.twinsun.com/tz/tz-link.htm
+echo "Looking for new tzdata..."
+wget -N --no-verbose 'ftp://elsie.nci.nih.gov/pub/tzdata*.tar.gz'
+zoneinfo_version_file=$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
+
+echo "Extracting $latest_version..."
+mkdir $latest_version
+tar -C $latest_version -zxf $latest_archive
+
+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