diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
new file mode 100644
index 0000000..705ed84
--- /dev/null
+++ b/tools/releasetools/common.py
@@ -0,0 +1,273 @@
+# Copyright (C) 2008 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 getopt
+import getpass
+import os
+import re
+import shutil
+import subprocess
+import sys
+import tempfile
+
+# missing in Python 2.4 and before
+if not hasattr(os, "SEEK_SET"):
+  os.SEEK_SET = 0
+
+class Options(object): pass
+OPTIONS = Options()
+OPTIONS.signapk_jar = "out/host/linux-x86/framework/signapk.jar"
+OPTIONS.max_image_size = {}
+OPTIONS.verbose = False
+OPTIONS.tempfiles = []
+
+
+class ExternalError(RuntimeError): pass
+
+
+def Run(args, **kwargs):
+  """Create and return a subprocess.Popen object, printing the command
+  line on the terminal if -v was specified."""
+  if OPTIONS.verbose:
+    print "  running: ", " ".join(args)
+  return subprocess.Popen(args, **kwargs)
+
+
+def LoadBoardConfig(fn):
+  """Parse a board_config.mk file looking for lines that specify the
+  maximum size of various images, and parse them into the
+  OPTIONS.max_image_size dict."""
+  OPTIONS.max_image_size = {}
+  for line in open(fn):
+    line = line.strip()
+    m = re.match(r"BOARD_(BOOT|RECOVERY|SYSTEM|USERDATA)IMAGE_MAX_SIZE"
+                 r"\s*:=\s*(\d+)", line)
+    if not m: continue
+
+    OPTIONS.max_image_size[m.group(1).lower() + ".img"] = int(m.group(2))
+
+
+def BuildAndAddBootableImage(sourcedir, targetname, output_zip):
+  """Take a kernel, cmdline, and ramdisk directory from the input (in
+  'sourcedir'), and turn them into a boot image.  Put the boot image
+  into the output zip file under the name 'targetname'."""
+
+  print "creating %s..." % (targetname,)
+
+  img = BuildBootableImage(sourcedir)
+
+  CheckSize(img, targetname)
+  output_zip.writestr(targetname, img)
+
+def BuildBootableImage(sourcedir):
+  """Take a kernel, cmdline, and ramdisk directory from the input (in
+  'sourcedir'), and turn them into a boot image.  Return the image data."""
+
+  ramdisk_img = tempfile.NamedTemporaryFile()
+  img = tempfile.NamedTemporaryFile()
+
+  p1 = Run(["mkbootfs", os.path.join(sourcedir, "RAMDISK")],
+           stdout=subprocess.PIPE)
+  p2 = Run(["gzip", "-n"], stdin=p1.stdout, stdout=ramdisk_img.file.fileno())
+
+  p2.wait()
+  p1.wait()
+  assert p1.returncode == 0, "mkbootfs of %s ramdisk failed" % (targetname,)
+  assert p2.returncode == 0, "gzip of %s ramdisk failed" % (targetname,)
+
+  cmdline = open(os.path.join(sourcedir, "cmdline")).read().rstrip("\n")
+  p = Run(["mkbootimg",
+           "--kernel", os.path.join(sourcedir, "kernel"),
+           "--cmdline", cmdline,
+           "--ramdisk", ramdisk_img.name,
+           "--output", img.name],
+          stdout=subprocess.PIPE)
+  p.communicate()
+  assert p.returncode == 0, "mkbootimg of %s image failed" % (targetname,)
+
+  img.seek(os.SEEK_SET, 0)
+  data = img.read()
+
+  ramdisk_img.close()
+  img.close()
+
+  return data
+
+
+def AddRecovery(output_zip):
+  BuildAndAddBootableImage(os.path.join(OPTIONS.input_tmp, "RECOVERY"),
+                           "recovery.img", output_zip)
+
+def AddBoot(output_zip):
+  BuildAndAddBootableImage(os.path.join(OPTIONS.input_tmp, "BOOT"),
+                           "boot.img", output_zip)
+
+def UnzipTemp(filename):
+  """Unzip the given archive into a temporary directory and return the name."""
+
+  tmp = tempfile.mkdtemp(prefix="targetfiles-")
+  OPTIONS.tempfiles.append(tmp)
+  p = Run(["unzip", "-q", filename, "-d", tmp], stdout=subprocess.PIPE)
+  p.communicate()
+  if p.returncode != 0:
+    raise ExternalError("failed to unzip input target-files \"%s\"" %
+                        (filename,))
+  return tmp
+
+
+def GetKeyPasswords(keylist):
+  """Given a list of keys, prompt the user to enter passwords for
+  those which require them.  Return a {key: password} dict.  password
+  will be None if the key has no password."""
+
+  key_passwords = {}
+  devnull = open("/dev/null", "w+b")
+  for k in sorted(keylist):
+    p = subprocess.Popen(["openssl", "pkcs8", "-in", k+".pk8",
+                          "-inform", "DER", "-nocrypt"],
+                         stdin=devnull.fileno(),
+                         stdout=devnull.fileno(),
+                         stderr=subprocess.STDOUT)
+    p.communicate()
+    if p.returncode == 0:
+      print "%s.pk8 does not require a password" % (k,)
+      key_passwords[k] = None
+    else:
+      key_passwords[k] = getpass.getpass("Enter password for %s.pk8> " % (k,))
+  devnull.close()
+  print
+  return key_passwords
+
+
+def SignFile(input_name, output_name, key, password, align=None):
+  """Sign the input_name zip/jar/apk, producing output_name.  Use the
+  given key and password (the latter may be None if the key does not
+  have a password.
+
+  If align is an integer > 1, zipalign is run to align stored files in
+  the output zip on 'align'-byte boundaries.
+  """
+  if align == 0 or align == 1:
+    align = None
+
+  if align:
+    temp = tempfile.NamedTemporaryFile()
+    sign_name = temp.name
+  else:
+    sign_name = output_name
+
+  p = subprocess.Popen(["java", "-jar", OPTIONS.signapk_jar,
+                        key + ".x509.pem",
+                        key + ".pk8",
+                        input_name, sign_name],
+                       stdin=subprocess.PIPE,
+                       stdout=subprocess.PIPE)
+  if password is not None:
+    password += "\n"
+  p.communicate(password)
+  if p.returncode != 0:
+    raise ExternalError("signapk.jar failed: return code %s" % (p.returncode,))
+
+  if align:
+    p = subprocess.Popen(["zipalign", "-f", str(align), sign_name, output_name])
+    p.communicate()
+    if p.returncode != 0:
+      raise ExternalError("zipalign failed: return code %s" % (p.returncode,))
+    temp.close()
+
+
+def CheckSize(data, target):
+  """Check the data string passed against the max size limit, if
+  any, for the given target.  Raise exception if the data is too big.
+  Print a warning if the data is nearing the maximum size."""
+  limit = OPTIONS.max_image_size.get(target, None)
+  if limit is None: return
+
+  size = len(data)
+  pct = float(size) * 100.0 / limit
+  msg = "%s size (%d) is %.2f%% of limit (%d)" % (target, size, pct, limit)
+  if pct >= 99.0:
+    raise ExternalError(msg)
+  elif pct >= 95.0:
+    print
+    print "  WARNING: ", msg
+    print
+  elif OPTIONS.verbose:
+    print "  ", msg
+
+
+COMMON_DOCSTRING = """
+  -p  (--path)  <dir>
+      Prepend <dir> to the list of places to search for binaries run
+      by this script.
+
+  -v  (--verbose)
+      Show command lines being executed.
+
+  -h  (--help)
+      Display this usage message and exit.
+"""
+
+def Usage(docstring):
+  print docstring.rstrip("\n")
+  print COMMON_DOCSTRING
+
+
+def ParseOptions(argv,
+                 docstring,
+                 extra_opts="", extra_long_opts=(),
+                 extra_option_handler=None):
+  """Parse the options in argv and return any arguments that aren't
+  flags.  docstring is the calling module's docstring, to be displayed
+  for errors and -h.  extra_opts and extra_long_opts are for flags
+  defined by the caller, which are processed by passing them to
+  extra_option_handler."""
+
+  try:
+    opts, args = getopt.getopt(
+        argv, "hvp:" + extra_opts,
+        ["help", "verbose", "path="] + list(extra_long_opts))
+  except getopt.GetoptError, err:
+    Usage(docstring)
+    print "**", str(err), "**"
+    sys.exit(2)
+
+  path_specified = False
+
+  for o, a in opts:
+    if o in ("-h", "--help"):
+      Usage(docstring)
+      sys.exit()
+    elif o in ("-v", "--verbose"):
+      OPTIONS.verbose = True
+    elif o in ("-p", "--path"):
+      os.environ["PATH"] = a + os.pathsep + os.environ["PATH"]
+      path_specified = True
+    else:
+      if extra_option_handler is None or not extra_option_handler(o, a):
+        assert False, "unknown option \"%s\"" % (o,)
+
+  if not path_specified:
+    os.environ["PATH"] = ("out/host/linux-x86/bin" + os.pathsep +
+                          os.environ["PATH"])
+
+  return args
+
+
+def Cleanup():
+  for i in OPTIONS.tempfiles:
+    if os.path.isdir(i):
+      shutil.rmtree(i)
+    else:
+      os.remove(i)