tools/releasetools/common.py

# 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 copy
import errno
import getopt
import getpass
import imp
import os
import platform
import re
import shlex
import shutil
import subprocess
import sys
import tempfile
import threading
import time
import zipfile

import blockimgdiff
import rangelib

from hashlib import sha1 as sha1


class Options(object):
  def __init__(self):
    platform_search_path = {
        "linux2": "out/host/linux-x86",
        "darwin": "out/host/darwin-x86",
    }

    self.search_path = platform_search_path.get(sys.platform, None)
    self.signapk_path = "framework/signapk.jar"  # Relative to search_path
    self.extra_signapk_args = []
    self.java_path = "java"  # Use the one on the path by default.
    self.java_args = "-Xmx2048m" # JVM Args
    self.public_key_suffix = ".x509.pem"
    self.private_key_suffix = ".pk8"
    # use otatools built boot_signer by default
    self.boot_signer_path = "boot_signer"
    self.boot_signer_args = []
    self.verity_signer_path = None
    self.verity_signer_args = []
    self.verbose = False
    self.tempfiles = []
    self.device_specific = None
    self.extras = {}
    self.info_dict = None
    self.worker_threads = None
    # Stash size cannot exceed cache_size * threshold.
    self.cache_size = None
    self.stash_threshold = 0.8


OPTIONS = Options()


# Values for "certificate" in apkcerts that mean special things.
SPECIAL_CERT_STRINGS = ("PRESIGNED", "EXTERNAL")


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 CloseInheritedPipes():
  """ Gmake in MAC OS has file descriptor (PIPE) leak. We close those fds
  before doing other work."""
  if platform.system() != "Darwin":
    return
  for d in range(3, 1025):
    try:
      stat = os.fstat(d)
      if stat is not None:
        pipebit = stat[0] & 0x1000
        if pipebit != 0:
          os.close(d)
    except OSError:
      pass


def LoadInfoDict(input_file, input_dir=None):
  """Read and parse the META/misc_info.txt key/value pairs from the
  input target files and return a dict."""

  def read_helper(fn):
    if isinstance(input_file, zipfile.ZipFile):
      return input_file.read(fn)
    else:
      path = os.path.join(input_file, *fn.split("/"))
      try:
        with open(path) as f:
          return f.read()
      except IOError as e:
        if e.errno == errno.ENOENT:
          raise KeyError(fn)
  d = {}
  try:
    d = LoadDictionaryFromLines(read_helper("META/misc_info.txt").split("\n"))
  except KeyError:
    # ok if misc_info.txt doesn't exist
    pass

  # backwards compatibility: These values used to be in their own
  # files.  Look for them, in case we're processing an old
  # target_files zip.

  if "mkyaffs2_extra_flags" not in d:
    try:
      d["mkyaffs2_extra_flags"] = read_helper(
          "META/mkyaffs2-extra-flags.txt").strip()
    except KeyError:
      # ok if flags don't exist
      pass

  if "recovery_api_version" not in d:
    try:
      d["recovery_api_version"] = read_helper(
          "META/recovery-api-version.txt").strip()
    except KeyError:
      raise ValueError("can't find recovery API version in input target-files")

  if "tool_extensions" not in d:
    try:
      d["tool_extensions"] = read_helper("META/tool-extensions.txt").strip()
    except KeyError:
      # ok if extensions don't exist
      pass

  if "fstab_version" not in d:
    d["fstab_version"] = "1"

  # A few properties are stored as links to the files in the out/ directory.
  # It works fine with the build system. However, they are no longer available
  # when (re)generating from target_files zip. If input_dir is not None, we
  # are doing repacking. Redirect those properties to the actual files in the
  # unzipped directory.
  if input_dir is not None:
    # We carry a copy of file_contexts.bin under META/. If not available,
    # search BOOT/RAMDISK/. Note that sometimes we may need a different file
    # to build images than the one running on device, such as when enabling
    # system_root_image. In that case, we must have the one for image
    # generation copied to META/.
    fc_basename = os.path.basename(d.get("selinux_fc", "file_contexts"))
    fc_config = os.path.join(input_dir, "META", fc_basename)
    if d.get("system_root_image") == "true":
      assert os.path.exists(fc_config)
    if not os.path.exists(fc_config):
      fc_config = os.path.join(input_dir, "BOOT", "RAMDISK", fc_basename)
      if not os.path.exists(fc_config):
        fc_config = None

    if fc_config:
      d["selinux_fc"] = fc_config

    # Similarly we need to redirect "ramdisk_dir" and "ramdisk_fs_config".
    if d.get("system_root_image") == "true":
      d["ramdisk_dir"] = os.path.join(input_dir, "ROOT")
      d["ramdisk_fs_config"] = os.path.join(
          input_dir, "META", "root_filesystem_config.txt")

  try:
    data = read_helper("META/imagesizes.txt")
    for line in data.split("\n"):
      if not line:
        continue
      name, value = line.split(" ", 1)
      if not value:
        continue
      if name == "blocksize":
        d[name] = value
      else:
        d[name + "_size"] = value
  except KeyError:
    pass

  def makeint(key):
    if key in d:
      d[key] = int(d[key], 0)

  makeint("recovery_api_version")
  makeint("blocksize")
  makeint("system_size")
  makeint("vendor_size")
  makeint("userdata_size")
  makeint("cache_size")
  makeint("recovery_size")
  makeint("boot_size")
  makeint("fstab_version")

  d["fstab"] = LoadRecoveryFSTab(read_helper, d["fstab_version"],
                                 d.get("system_root_image", False))
  d["build.prop"] = LoadBuildProp(read_helper)
  return d

def LoadBuildProp(read_helper):
  try:
    data = read_helper("SYSTEM/build.prop")
  except KeyError:
    print "Warning: could not find SYSTEM/build.prop in %s" % zip
    data = ""
  return LoadDictionaryFromLines(data.split("\n"))

def LoadDictionaryFromLines(lines):
  d = {}
  for line in lines:
    line = line.strip()
    if not line or line.startswith("#"):
      continue
    if "=" in line:
      name, value = line.split("=", 1)
      d[name] = value
  return d

def LoadRecoveryFSTab(read_helper, fstab_version, system_root_image=False):
  class Partition(object):
    def __init__(self, mount_point, fs_type, device, length, device2, context):
      self.mount_point = mount_point
      self.fs_type = fs_type
      self.device = device
      self.length = length
      self.device2 = device2
      self.context = context

  try:
    data = read_helper("RECOVERY/RAMDISK/etc/recovery.fstab")
  except KeyError:
    print "Warning: could not find RECOVERY/RAMDISK/etc/recovery.fstab"
    data = ""

  if fstab_version == 1:
    d = {}
    for line in data.split("\n"):
      line = line.strip()
      if not line or line.startswith("#"):
        continue
      pieces = line.split()
      if not 3 <= len(pieces) <= 4:
        raise ValueError("malformed recovery.fstab line: \"%s\"" % (line,))
      options = None
      if len(pieces) >= 4:
        if pieces[3].startswith("/"):
          device2 = pieces[3]
          if len(pieces) >= 5:
            options = pieces[4]
        else:
          device2 = None
          options = pieces[3]
      else:
        device2 = None

      mount_point = pieces[0]
      length = 0
      if options:
        options = options.split(",")
        for i in options:
          if i.startswith("length="):
            length = int(i[7:])
          else:
            print "%s: unknown option \"%s\"" % (mount_point, i)

      d[mount_point] = Partition(mount_point=mount_point, fs_type=pieces[1],
                                 device=pieces[2], length=length,
                                 device2=device2)

  elif fstab_version == 2:
    d = {}
    for line in data.split("\n"):
      line = line.strip()
      if not line or line.startswith("#"):
        continue
      # <src> <mnt_point> <type> <mnt_flags and options> <fs_mgr_flags>
      pieces = line.split()
      if len(pieces) != 5:
        raise ValueError("malformed recovery.fstab line: \"%s\"" % (line,))

      # Ignore entries that are managed by vold
      options = pieces[4]
      if "voldmanaged=" in options:
        continue

      # It's a good line, parse it
      length = 0
      options = options.split(",")
      for i in options:
        if i.startswith("length="):
          length = int(i[7:])
        else:
          # Ignore all unknown options in the unified fstab
          continue

      mount_flags = pieces[3]
      # Honor the SELinux context if present.
      context = None
      for i in mount_flags.split(","):
        if i.startswith("context="):
          context = i

      mount_point = pieces[1]
      d[mount_point] = Partition(mount_point=mount_point, fs_type=pieces[2],
                                 device=pieces[0], length=length,
                                 device2=None, context=context)

  else:
    raise ValueError("Unknown fstab_version: \"%d\"" % (fstab_version,))

  # / is used for the system mount point when the root directory is included in
  # system. Other areas assume system is always at "/system" so point /system
  # at /.
  if system_root_image:
    assert not d.has_key("/system") and d.has_key("/")
    d["/system"] = d["/"]
  return d


def DumpInfoDict(d):
  for k, v in sorted(d.items()):
    print "%-25s = (%s) %s" % (k, type(v).__name__, v)


def _BuildBootableImage(sourcedir, fs_config_file, info_dict=None,
                        has_ramdisk=False):
  """Build a bootable image from the specified sourcedir.

  Take a kernel, cmdline, and optionally a ramdisk directory from the input (in
  'sourcedir'), and turn them into a boot image.  Return the image data, or
  None if sourcedir does not appear to contains files for building the
  requested image."""

  def make_ramdisk():
    ramdisk_img = tempfile.NamedTemporaryFile()

    if os.access(fs_config_file, os.F_OK):
      cmd = ["mkbootfs", "-f", fs_config_file,
             os.path.join(sourcedir, "RAMDISK")]
    else:
      cmd = ["mkbootfs", os.path.join(sourcedir, "RAMDISK")]
    p1 = Run(cmd, stdout=subprocess.PIPE)
    p2 = Run(["minigzip"], stdin=p1.stdout, stdout=ramdisk_img.file.fileno())

    p2.wait()
    p1.wait()
    assert p1.returncode == 0, "mkbootfs of %s ramdisk failed" % (sourcedir,)
    assert p2.returncode == 0, "minigzip of %s ramdisk failed" % (sourcedir,)

    return ramdisk_img

  if not os.access(os.path.join(sourcedir, "kernel"), os.F_OK):
    return None

  if has_ramdisk and not os.access(os.path.join(sourcedir, "RAMDISK"), os.F_OK):
    return None

  if info_dict is None:
    info_dict = OPTIONS.info_dict

  img = tempfile.NamedTemporaryFile()

  if has_ramdisk:
    ramdisk_img = make_ramdisk()

  # use MKBOOTIMG from environ, or "mkbootimg" if empty or not set
  mkbootimg = os.getenv('MKBOOTIMG') or "mkbootimg"

  cmd = [mkbootimg, "--kernel", os.path.join(sourcedir, "kernel")]

  fn = os.path.join(sourcedir, "second")
  if os.access(fn, os.F_OK):
    cmd.append("--second")
    cmd.append(fn)

  fn = os.path.join(sourcedir, "cmdline")
  if os.access(fn, os.F_OK):
    cmd.append("--cmdline")
    cmd.append(open(fn).read().rstrip("\n"))

  fn = os.path.join(sourcedir, "base")
  if os.access(fn, os.F_OK):
    cmd.append("--base")
    cmd.append(open(fn).read().rstrip("\n"))

  fn = os.path.join(sourcedir, "pagesize")
  if os.access(fn, os.F_OK):
    cmd.append("--pagesize")
    cmd.append(open(fn).read().rstrip("\n"))

  args = info_dict.get("mkbootimg_args", None)
  if args and args.strip():
    cmd.extend(shlex.split(args))

  if has_ramdisk:
    cmd.extend(["--ramdisk", ramdisk_img.name])

  img_unsigned = None
  if info_dict.get("vboot", None):
    img_unsigned = tempfile.NamedTemporaryFile()
    cmd.extend(["--output", img_unsigned.name])
  else:
    cmd.extend(["--output", img.name])

  p = Run(cmd, stdout=subprocess.PIPE)
  p.communicate()
  assert p.returncode == 0, "mkbootimg of %s image failed" % (
      os.path.basename(sourcedir),)

  if (info_dict.get("boot_signer", None) == "true" and
      info_dict.get("verity_key", None)):
    path = "/" + os.path.basename(sourcedir).lower()
    cmd = [OPTIONS.boot_signer_path]
    cmd.extend(OPTIONS.boot_signer_args)
    cmd.extend([path, img.name,
                info_dict["verity_key"] + ".pk8",
                info_dict["verity_key"] + ".x509.pem", img.name])
    p = Run(cmd, stdout=subprocess.PIPE)
    p.communicate()
    assert p.returncode == 0, "boot_signer of %s image failed" % path

  # Sign the image if vboot is non-empty.
  elif info_dict.get("vboot", None):
    path = "/" + os.path.basename(sourcedir).lower()
    img_keyblock = tempfile.NamedTemporaryFile()
    cmd = [info_dict["vboot_signer_cmd"], info_dict["futility"],
           img_unsigned.name, info_dict["vboot_key"] + ".vbpubk",
           info_dict["vboot_key"] + ".vbprivk", img_keyblock.name,
           img.name]
    p = Run(cmd, stdout=subprocess.PIPE)
    p.communicate()
    assert p.returncode == 0, "vboot_signer of %s image failed" % path

    # Clean up the temp files.
    img_unsigned.close()
    img_keyblock.close()

  img.seek(os.SEEK_SET, 0)
  data = img.read()

  if has_ramdisk:
    ramdisk_img.close()
  img.close()

  return data


def GetBootableImage(name, prebuilt_name, unpack_dir, tree_subdir,
                     info_dict=None):
  """Return a File object with the desired bootable image.

  Look for it in 'unpack_dir'/BOOTABLE_IMAGES under the name 'prebuilt_name',
  otherwise look for it under 'unpack_dir'/IMAGES, otherwise construct it from
  the source files in 'unpack_dir'/'tree_subdir'."""

  prebuilt_path = os.path.join(unpack_dir, "BOOTABLE_IMAGES", prebuilt_name)
  if os.path.exists(prebuilt_path):
    print "using prebuilt %s from BOOTABLE_IMAGES..." % (prebuilt_name,)
    return File.FromLocalFile(name, prebuilt_path)

  prebuilt_path = os.path.join(unpack_dir, "IMAGES", prebuilt_name)
  if os.path.exists(prebuilt_path):
    print "using prebuilt %s from IMAGES..." % (prebuilt_name,)
    return File.FromLocalFile(name, prebuilt_path)

  print "building image from target_files %s..." % (tree_subdir,)

  if info_dict is None:
    info_dict = OPTIONS.info_dict

  # With system_root_image == "true", we don't pack ramdisk into the boot image.
  has_ramdisk = (info_dict.get("system_root_image", None) != "true" or
                 prebuilt_name != "boot.img")

  fs_config = "META/" + tree_subdir.lower() + "_filesystem_config.txt"
  data = _BuildBootableImage(os.path.join(unpack_dir, tree_subdir),
                             os.path.join(unpack_dir, fs_config),
                             info_dict, has_ramdisk)
  if data:
    return File(name, data)
  return None


def UnzipTemp(filename, pattern=None):
  """Unzip the given archive into a temporary directory and return the name.

  If filename is of the form "foo.zip+bar.zip", unzip foo.zip into a
  temp dir, then unzip bar.zip into that_dir/BOOTABLE_IMAGES.

  Returns (tempdir, zipobj) where zipobj is a zipfile.ZipFile (of the
  main file), open for reading.
  """

  tmp = tempfile.mkdtemp(prefix="targetfiles-")
  OPTIONS.tempfiles.append(tmp)

  def unzip_to_dir(filename, dirname):
    cmd = ["unzip", "-o", "-q", filename, "-d", dirname]
    if pattern is not None:
      cmd.append(pattern)
    p = Run(cmd, stdout=subprocess.PIPE)
    p.communicate()
    if p.returncode != 0:
      raise ExternalError("failed to unzip input target-files \"%s\"" %
                          (filename,))

  m = re.match(r"^(.*[.]zip)\+(.*[.]zip)$", filename, re.IGNORECASE)
  if m:
    unzip_to_dir(m.group(1), tmp)
    unzip_to_dir(m.group(2), os.path.join(tmp, "BOOTABLE_IMAGES"))
    filename = m.group(1)
  else:
    unzip_to_dir(filename, tmp)

  return tmp, zipfile.ZipFile(filename, "r")


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."""

  no_passwords = []
  need_passwords = []
  key_passwords = {}
  devnull = open("/dev/null", "w+b")
  for k in sorted(keylist):
    # We don't need a password for things that aren't really keys.
    if k in SPECIAL_CERT_STRINGS:
      no_passwords.append(k)
      continue

    p = Run(["openssl", "pkcs8", "-in", k+OPTIONS.private_key_suffix,
             "-inform", "DER", "-nocrypt"],
            stdin=devnull.fileno(),
            stdout=devnull.fileno(),
            stderr=subprocess.STDOUT)
    p.communicate()
    if p.returncode == 0:
      # Definitely an unencrypted key.
      no_passwords.append(k)
    else:
      p = Run(["openssl", "pkcs8", "-in", k+OPTIONS.private_key_suffix,
               "-inform", "DER", "-passin", "pass:"],
              stdin=devnull.fileno(),
              stdout=devnull.fileno(),
              stderr=subprocess.PIPE)
      _, stderr = p.communicate()
      if p.returncode == 0:
        # Encrypted key with empty string as password.
        key_passwords[k] = ''
      elif stderr.startswith('Error decrypting key'):
        # Definitely encrypted key.
        # It would have said "Error reading key" if it didn't parse correctly.
        need_passwords.append(k)
      else:
        # Potentially, a type of key that openssl doesn't understand.
        # We'll let the routines in signapk.jar handle it.
        no_passwords.append(k)
  devnull.close()

  key_passwords.update(PasswordManager().GetPasswords(need_passwords))
  key_passwords.update(dict.fromkeys(no_passwords, None))
  return key_passwords


def SignFile(input_name, output_name, key, password, align=None,
             whole_file=False):
  """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 whole_file is true, use the "-w" option to SignApk to embed a
  signature that covers the whole file in the archive comment of the
  zip file.
  """

  if align == 0 or align == 1:
    align = None

  if align:
    temp = tempfile.NamedTemporaryFile()
    sign_name = temp.name
  else:
    sign_name = output_name

  cmd = [OPTIONS.java_path, OPTIONS.java_args, "-jar",
         os.path.join(OPTIONS.search_path, OPTIONS.signapk_path)]
  cmd.extend(OPTIONS.extra_signapk_args)
  if whole_file:
    cmd.append("-w")
  cmd.extend([key + OPTIONS.public_key_suffix,
              key + OPTIONS.private_key_suffix,
              input_name, sign_name])

  p = Run(cmd, 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 = Run(["zipalign", "-f", "-p", 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, info_dict):
  """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."""

  if target.endswith(".img"):
    target = target[:-4]
  mount_point = "/" + target

  fs_type = None
  limit = None
  if info_dict["fstab"]:
    if mount_point == "/userdata":
      mount_point = "/data"
    p = info_dict["fstab"][mount_point]
    fs_type = p.fs_type
    device = p.device
    if "/" in device:
      device = device[device.rfind("/")+1:]
    limit = info_dict.get(device + "_size", None)
  if not fs_type or not limit:
    return

  if fs_type == "yaffs2":
    # image size should be increased by 1/64th to account for the
    # spare area (64 bytes per 2k page)
    limit = limit / 2048 * (2048+64)
  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


def ReadApkCerts(tf_zip):
  """Given a target_files ZipFile, parse the META/apkcerts.txt file
  and return a {package: cert} dict."""
  certmap = {}
  for line in tf_zip.read("META/apkcerts.txt").split("\n"):
    line = line.strip()
    if not line:
      continue
    m = re.match(r'^name="(.*)"\s+certificate="(.*)"\s+'
                 r'private_key="(.*)"$', line)
    if m:
      name, cert, privkey = m.groups()
      public_key_suffix_len = len(OPTIONS.public_key_suffix)
      private_key_suffix_len = len(OPTIONS.private_key_suffix)
      if cert in SPECIAL_CERT_STRINGS and not privkey:
        certmap[name] = cert
      elif (cert.endswith(OPTIONS.public_key_suffix) and
            privkey.endswith(OPTIONS.private_key_suffix) and
            cert[:-public_key_suffix_len] == privkey[:-private_key_suffix_len]):
        certmap[name] = cert[:-public_key_suffix_len]
      else:
        raise ValueError("failed to parse line from apkcerts.txt:\n" + line)
  return certmap


COMMON_DOCSTRING = """
  -p  (--path)  <dir>
      Prepend <dir>/bin to the list of places to search for binaries
      run by this script, and expect to find jars in <dir>/framework.

  -s  (--device_specific) <file>
      Path to the python module containing device-specific
      releasetools code.

  -x  (--extra)  <key=value>
      Add a key/value pair to the 'extras' dict, which device-specific
      extension code may look at.

  -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:s:x:" + extra_opts,
        ["help", "verbose", "path=", "signapk_path=", "extra_signapk_args=",
         "java_path=", "java_args=", "public_key_suffix=",
         "private_key_suffix=", "boot_signer_path=", "boot_signer_args=",
         "verity_signer_path=", "verity_signer_args=", "device_specific=",
         "extra="] +
        list(extra_long_opts))
  except getopt.GetoptError as err:
    Usage(docstring)
    print "**", str(err), "**"
    sys.exit(2)

  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"):
      OPTIONS.search_path = a
    elif o in ("--signapk_path",):
      OPTIONS.signapk_path = a
    elif o in ("--extra_signapk_args",):
      OPTIONS.extra_signapk_args = shlex.split(a)
    elif o in ("--java_path",):
      OPTIONS.java_path = a
    elif o in ("--java_args",):
      OPTIONS.java_args = a
    elif o in ("--public_key_suffix",):
      OPTIONS.public_key_suffix = a
    elif o in ("--private_key_suffix",):
      OPTIONS.private_key_suffix = a
    elif o in ("--boot_signer_path",):
      OPTIONS.boot_signer_path = a
    elif o in ("--boot_signer_args",):
      OPTIONS.boot_signer_args = shlex.split(a)
    elif o in ("--verity_signer_path",):
      OPTIONS.verity_signer_path = a
    elif o in ("--verity_signer_args",):
      OPTIONS.verity_signer_args = shlex.split(a)
    elif o in ("-s", "--device_specific"):
      OPTIONS.device_specific = a
    elif o in ("-x", "--extra"):
      key, value = a.split("=", 1)
      OPTIONS.extras[key] = value
    else:
      if extra_option_handler is None or not extra_option_handler(o, a):
        assert False, "unknown option \"%s\"" % (o,)

  if OPTIONS.search_path:
    os.environ["PATH"] = (os.path.join(OPTIONS.search_path, "bin") +
                          os.pathsep + os.environ["PATH"])

  return args


def MakeTempFile(prefix=None, suffix=None):
  """Make a temp file and add it to the list of things to be deleted
  when Cleanup() is called.  Return the filename."""
  fd, fn = tempfile.mkstemp(prefix=prefix, suffix=suffix)
  os.close(fd)
  OPTIONS.tempfiles.append(fn)
  return fn


def Cleanup():
  for i in OPTIONS.tempfiles:
    if os.path.isdir(i):
      shutil.rmtree(i)
    else:
      os.remove(i)


class PasswordManager(object):
  def __init__(self):
    self.editor = os.getenv("EDITOR", None)
    self.pwfile = os.getenv("ANDROID_PW_FILE", None)

  def GetPasswords(self, items):
    """Get passwords corresponding to each string in 'items',
    returning a dict.  (The dict may have keys in addition to the
    values in 'items'.)

    Uses the passwords in $ANDROID_PW_FILE if available, letting the
    user edit that file to add more needed passwords.  If no editor is
    available, or $ANDROID_PW_FILE isn't define, prompts the user
    interactively in the ordinary way.
    """

    current = self.ReadFile()

    first = True
    while True:
      missing = []
      for i in items:
        if i not in current or not current[i]:
          missing.append(i)
      # Are all the passwords already in the file?
      if not missing:
        return current

      for i in missing:
        current[i] = ""

      if not first:
        print "key file %s still missing some passwords." % (self.pwfile,)
        answer = raw_input("try to edit again? [y]> ").strip()
        if answer and answer[0] not in 'yY':
          raise RuntimeError("key passwords unavailable")
      first = False

      current = self.UpdateAndReadFile(current)

  def PromptResult(self, current): # pylint: disable=no-self-use
    """Prompt the user to enter a value (password) for each key in
    'current' whose value is fales.  Returns a new dict with all the
    values.
    """
    result = {}
    for k, v in sorted(current.iteritems()):
      if v:
        result[k] = v
      else:
        while True:
          result[k] = getpass.getpass(
              "Enter password for %s key> " % k).strip()
          if result[k]:
            break
    return result

  def UpdateAndReadFile(self, current):
    if not self.editor or not self.pwfile:
      return self.PromptResult(current)

    f = open(self.pwfile, "w")
    os.chmod(self.pwfile, 0o600)
    f.write("# Enter key passwords between the [[[ ]]] brackets.\n")
    f.write("# (Additional spaces are harmless.)\n\n")

    first_line = None
    sorted_list = sorted([(not v, k, v) for (k, v) in current.iteritems()])
    for i, (_, k, v) in enumerate(sorted_list):
      f.write("[[[  %s  ]]] %s\n" % (v, k))
      if not v and first_line is None:
        # position cursor on first line with no password.
        first_line = i + 4
    f.close()

    p = Run([self.editor, "+%d" % (first_line,), self.pwfile])
    _, _ = p.communicate()

    return self.ReadFile()

  def ReadFile(self):
    result = {}
    if self.pwfile is None:
      return result
    try:
      f = open(self.pwfile, "r")
      for line in f:
        line = line.strip()
        if not line or line[0] == '#':
          continue
        m = re.match(r"^\[\[\[\s*(.*?)\s*\]\]\]\s*(\S+)$", line)
        if not m:
          print "failed to parse password file: ", line
        else:
          result[m.group(2)] = m.group(1)
      f.close()
    except IOError as e:
      if e.errno != errno.ENOENT:
        print "error reading password file: ", str(e)
    return result


def ZipWrite(zip_file, filename, arcname=None, perms=0o644,
             compress_type=None):
  import datetime

  # http://b/18015246
  # Python 2.7's zipfile implementation wrongly thinks that zip64 is required
  # for files larger than 2GiB. We can work around this by adjusting their
  # limit. Note that `zipfile.writestr()` will not work for strings larger than
  # 2GiB. The Python interpreter sometimes rejects strings that large (though
  # it isn't clear to me exactly what circumstances cause this).
  # `zipfile.write()` must be used directly to work around this.
  #
  # This mess can be avoided if we port to python3.
  saved_zip64_limit = zipfile.ZIP64_LIMIT
  zipfile.ZIP64_LIMIT = (1 << 32) - 1

  if compress_type is None:
    compress_type = zip_file.compression
  if arcname is None:
    arcname = filename

  saved_stat = os.stat(filename)

  try:
    # `zipfile.write()` doesn't allow us to pass ZipInfo, so just modify the
    # file to be zipped and reset it when we're done.
    os.chmod(filename, perms)

    # Use a fixed timestamp so the output is repeatable.
    epoch = datetime.datetime.fromtimestamp(0)
    timestamp = (datetime.datetime(2009, 1, 1) - epoch).total_seconds()
    os.utime(filename, (timestamp, timestamp))

    zip_file.write(filename, arcname=arcname, compress_type=compress_type)
  finally:
    os.chmod(filename, saved_stat.st_mode)
    os.utime(filename, (saved_stat.st_atime, saved_stat.st_mtime))
    zipfile.ZIP64_LIMIT = saved_zip64_limit


def ZipWriteStr(zip_file, zinfo_or_arcname, data, perms=None,
                compress_type=None):
  """Wrap zipfile.writestr() function to work around the zip64 limit.

  Even with the ZIP64_LIMIT workaround, it won't allow writing a string
  longer than 2GiB. It gives 'OverflowError: size does not fit in an int'
  when calling crc32(bytes).

  But it still works fine to write a shorter string into a large zip file.
  We should use ZipWrite() whenever possible, and only use ZipWriteStr()
  when we know the string won't be too long.
  """

  saved_zip64_limit = zipfile.ZIP64_LIMIT
  zipfile.ZIP64_LIMIT = (1 << 32) - 1

  if not isinstance(zinfo_or_arcname, zipfile.ZipInfo):
    zinfo = zipfile.ZipInfo(filename=zinfo_or_arcname)
    zinfo.compress_type = zip_file.compression
    if perms is None:
      perms = 0o100644
  else:
    zinfo = zinfo_or_arcname

  # If compress_type is given, it overrides the value in zinfo.
  if compress_type is not None:
    zinfo.compress_type = compress_type

  # If perms is given, it has a priority.
  if perms is not None:
    # If perms doesn't set the file type, mark it as a regular file.
    if perms & 0o770000 == 0:
      perms |= 0o100000
    zinfo.external_attr = perms << 16

  # Use a fixed timestamp so the output is repeatable.
  zinfo.date_time = (2009, 1, 1, 0, 0, 0)

  zip_file.writestr(zinfo, data)
  zipfile.ZIP64_LIMIT = saved_zip64_limit


def ZipClose(zip_file):
  # http://b/18015246
  # zipfile also refers to ZIP64_LIMIT during close() when it writes out the
  # central directory.
  saved_zip64_limit = zipfile.ZIP64_LIMIT
  zipfile.ZIP64_LIMIT = (1 << 32) - 1

  zip_file.close()

  zipfile.ZIP64_LIMIT = saved_zip64_limit


class DeviceSpecificParams(object):
  module = None
  def __init__(self, **kwargs):
    """Keyword arguments to the constructor become attributes of this
    object, which is passed to all functions in the device-specific
    module."""
    for k, v in kwargs.iteritems():
      setattr(self, k, v)
    self.extras = OPTIONS.extras

    if self.module is None:
      path = OPTIONS.device_specific
      if not path:
        return
      try:
        if os.path.isdir(path):
          info = imp.find_module("releasetools", [path])
        else:
          d, f = os.path.split(path)
          b, x = os.path.splitext(f)
          if x == ".py":
            f = b
          info = imp.find_module(f, [d])
        print "loaded device-specific extensions from", path
        self.module = imp.load_module("device_specific", *info)
      except ImportError:
        print "unable to load device-specific module; assuming none"

  def _DoCall(self, function_name, *args, **kwargs):
    """Call the named function in the device-specific module, passing
    the given args and kwargs.  The first argument to the call will be
    the DeviceSpecific object itself.  If there is no module, or the
    module does not define the function, return the value of the
    'default' kwarg (which itself defaults to None)."""
    if self.module is None or not hasattr(self.module, function_name):
      return kwargs.get("default", None)
    return getattr(self.module, function_name)(*((self,) + args), **kwargs)

  def FullOTA_Assertions(self):
    """Called after emitting the block of assertions at the top of a
    full OTA package.  Implementations can add whatever additional
    assertions they like."""
    return self._DoCall("FullOTA_Assertions")

  def FullOTA_InstallBegin(self):
    """Called at the start of full OTA installation."""
    return self._DoCall("FullOTA_InstallBegin")

  def FullOTA_InstallEnd(self):
    """Called at the end of full OTA installation; typically this is
    used to install the image for the device's baseband processor."""
    return self._DoCall("FullOTA_InstallEnd")

  def IncrementalOTA_Assertions(self):
    """Called after emitting the block of assertions at the top of an
    incremental OTA package.  Implementations can add whatever
    additional assertions they like."""
    return self._DoCall("IncrementalOTA_Assertions")

  def IncrementalOTA_VerifyBegin(self):
    """Called at the start of the verification phase of incremental
    OTA installation; additional checks can be placed here to abort
    the script before any changes are made."""
    return self._DoCall("IncrementalOTA_VerifyBegin")

  def IncrementalOTA_VerifyEnd(self):
    """Called at the end of the verification phase of incremental OTA
    installation; additional checks can be placed here to abort the
    script before any changes are made."""
    return self._DoCall("IncrementalOTA_VerifyEnd")

  def IncrementalOTA_InstallBegin(self):
    """Called at the start of incremental OTA installation (after
    verification is complete)."""
    return self._DoCall("IncrementalOTA_InstallBegin")

  def IncrementalOTA_InstallEnd(self):
    """Called at the end of incremental OTA installation; typically
    this is used to install the image for the device's baseband
    processor."""
    return self._DoCall("IncrementalOTA_InstallEnd")

class File(object):
  def __init__(self, name, data):
    self.name = name
    self.data = data
    self.size = len(data)
    self.sha1 = sha1(data).hexdigest()

  @classmethod
  def FromLocalFile(cls, name, diskname):
    f = open(diskname, "rb")
    data = f.read()
    f.close()
    return File(name, data)

  def WriteToTemp(self):
    t = tempfile.NamedTemporaryFile()
    t.write(self.data)
    t.flush()
    return t

  def AddToZip(self, z, compression=None):
    ZipWriteStr(z, self.name, self.data, compress_type=compression)

DIFF_PROGRAM_BY_EXT = {
    ".gz" : "imgdiff",
    ".zip" : ["imgdiff", "-z"],
    ".jar" : ["imgdiff", "-z"],
    ".apk" : ["imgdiff", "-z"],
    ".img" : "imgdiff",
    }

class Difference(object):
  def __init__(self, tf, sf, diff_program=None):
    self.tf = tf
    self.sf = sf
    self.patch = None
    self.diff_program = diff_program

  def ComputePatch(self):
    """Compute the patch (as a string of data) needed to turn sf into
    tf.  Returns the same tuple as GetPatch()."""

    tf = self.tf
    sf = self.sf

    if self.diff_program:
      diff_program = self.diff_program
    else:
      ext = os.path.splitext(tf.name)[1]
      diff_program = DIFF_PROGRAM_BY_EXT.get(ext, "bsdiff")

    ttemp = tf.WriteToTemp()
    stemp = sf.WriteToTemp()

    ext = os.path.splitext(tf.name)[1]

    try:
      ptemp = tempfile.NamedTemporaryFile()
      if isinstance(diff_program, list):
        cmd = copy.copy(diff_program)
      else:
        cmd = [diff_program]
      cmd.append(stemp.name)
      cmd.append(ttemp.name)
      cmd.append(ptemp.name)
      p = Run(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
      err = []
      def run():
        _, e = p.communicate()
        if e:
          err.append(e)
      th = threading.Thread(target=run)
      th.start()
      th.join(timeout=300)   # 5 mins
      if th.is_alive():
        print "WARNING: diff command timed out"
        p.terminate()
        th.join(5)
        if th.is_alive():
          p.kill()
          th.join()

      if err or p.returncode != 0:
        print "WARNING: failure running %s:\n%s\n" % (
            diff_program, "".join(err))
        self.patch = None
        return None, None, None
      diff = ptemp.read()
    finally:
      ptemp.close()
      stemp.close()
      ttemp.close()

    self.patch = diff
    return self.tf, self.sf, self.patch


  def GetPatch(self):
    """Return a tuple (target_file, source_file, patch_data).
    patch_data may be None if ComputePatch hasn't been called, or if
    computing the patch failed."""
    return self.tf, self.sf, self.patch


def ComputeDifferences(diffs):
  """Call ComputePatch on all the Difference objects in 'diffs'."""
  print len(diffs), "diffs to compute"

  # Do the largest files first, to try and reduce the long-pole effect.
  by_size = [(i.tf.size, i) for i in diffs]
  by_size.sort(reverse=True)
  by_size = [i[1] for i in by_size]

  lock = threading.Lock()
  diff_iter = iter(by_size)   # accessed under lock

  def worker():
    try:
      lock.acquire()
      for d in diff_iter:
        lock.release()
        start = time.time()
        d.ComputePatch()
        dur = time.time() - start
        lock.acquire()

        tf, sf, patch = d.GetPatch()
        if sf.name == tf.name:
          name = tf.name
        else:
          name = "%s (%s)" % (tf.name, sf.name)
        if patch is None:
          print "patching failed!                                  %s" % (name,)
        else:
          print "%8.2f sec %8d / %8d bytes (%6.2f%%) %s" % (
              dur, len(patch), tf.size, 100.0 * len(patch) / tf.size, name)
      lock.release()
    except Exception as e:
      print e
      raise

  # start worker threads; wait for them all to finish.
  threads = [threading.Thread(target=worker)
             for i in range(OPTIONS.worker_threads)]
  for th in threads:
    th.start()
  while threads:
    threads.pop().join()


class BlockDifference(object):
  def __init__(self, partition, tgt, src=None, check_first_block=False,
               version=None):
    self.tgt = tgt
    self.src = src
    self.partition = partition
    self.check_first_block = check_first_block

    # Due to http://b/20939131, check_first_block is disabled temporarily.
    assert not self.check_first_block

    if version is None:
      version = 1
      if OPTIONS.info_dict:
        version = max(
            int(i) for i in
            OPTIONS.info_dict.get("blockimgdiff_versions", "1").split(","))
    self.version = version

    b = blockimgdiff.BlockImageDiff(tgt, src, threads=OPTIONS.worker_threads,
                                    version=self.version)
    tmpdir = tempfile.mkdtemp()
    OPTIONS.tempfiles.append(tmpdir)
    self.path = os.path.join(tmpdir, partition)
    b.Compute(self.path)

    _, self.device = GetTypeAndDevice("/" + partition, OPTIONS.info_dict)

  def WriteScript(self, script, output_zip, progress=None):
    if not self.src:
      # write the output unconditionally
      script.Print("Patching %s image unconditionally..." % (self.partition,))
    else:
      script.Print("Patching %s image after verification." % (self.partition,))

    if progress:
      script.ShowProgress(progress, 0)
    self._WriteUpdate(script, output_zip)
    self._WritePostInstallVerifyScript(script)

  def WriteVerifyScript(self, script):
    partition = self.partition
    if not self.src:
      script.Print("Image %s will be patched unconditionally." % (partition,))
    else:
      ranges = self.src.care_map.subtract(self.src.clobbered_blocks)
      ranges_str = ranges.to_string_raw()
      if self.version >= 3:
        script.AppendExtra(('if (range_sha1("%s", "%s") == "%s" || '
                            'block_image_verify("%s", '
                            'package_extract_file("%s.transfer.list"), '
                            '"%s.new.dat", "%s.patch.dat")) then') % (
                            self.device, ranges_str, self.src.TotalSha1(),
                            self.device, partition, partition, partition))
      else:
        script.AppendExtra('if range_sha1("%s", "%s") == "%s" then' % (
                           self.device, ranges_str, self.src.TotalSha1()))
      script.Print('Verified %s image...' % (partition,))
      script.AppendExtra('else')

      # When generating incrementals for the system and vendor partitions,
      # explicitly check the first block (which contains the superblock) of
      # the partition to see if it's what we expect. If this check fails,
      # give an explicit log message about the partition having been
      # remounted R/W (the most likely explanation) and the need to flash to
      # get OTAs working again.
      if self.check_first_block:
        self._CheckFirstBlock(script)

      # Abort the OTA update. Note that the incremental OTA cannot be applied
      # even if it may match the checksum of the target partition.
      # a) If version < 3, operations like move and erase will make changes
      #    unconditionally and damage the partition.
      # b) If version >= 3, it won't even reach here.
      script.AppendExtra(('abort("%s partition has unexpected contents");\n'
                          'endif;') % (partition,))

  def _WritePostInstallVerifyScript(self, script):
    partition = self.partition
    script.Print('Verifying the updated %s image...' % (partition,))
    # Unlike pre-install verification, clobbered_blocks should not be ignored.
    ranges = self.tgt.care_map
    ranges_str = ranges.to_string_raw()
    script.AppendExtra('if range_sha1("%s", "%s") == "%s" then' % (
                       self.device, ranges_str,
                       self.tgt.TotalSha1(include_clobbered_blocks=True)))

    # Bug: 20881595
    # Verify that extended blocks are really zeroed out.
    if self.tgt.extended:
      ranges_str = self.tgt.extended.to_string_raw()
      script.AppendExtra('if range_sha1("%s", "%s") == "%s" then' % (
                         self.device, ranges_str,
                         self._HashZeroBlocks(self.tgt.extended.size())))
      script.Print('Verified the updated %s image.' % (partition,))
      script.AppendExtra(
          'else\n'
          '  abort("%s partition has unexpected non-zero contents after OTA '
          'update");\n'
          'endif;' % (partition,))
    else:
      script.Print('Verified the updated %s image.' % (partition,))

    script.AppendExtra(
        'else\n'
        '  abort("%s partition has unexpected contents after OTA update");\n'
        'endif;' % (partition,))

  def _WriteUpdate(self, script, output_zip):
    ZipWrite(output_zip,
             '{}.transfer.list'.format(self.path),
             '{}.transfer.list'.format(self.partition))
    ZipWrite(output_zip,
             '{}.new.dat'.format(self.path),
             '{}.new.dat'.format(self.partition))
    ZipWrite(output_zip,
             '{}.patch.dat'.format(self.path),
             '{}.patch.dat'.format(self.partition),
             compress_type=zipfile.ZIP_STORED)

    call = ('block_image_update("{device}", '
            'package_extract_file("{partition}.transfer.list"), '
            '"{partition}.new.dat", "{partition}.patch.dat");\n'.format(
                device=self.device, partition=self.partition))
    script.AppendExtra(script.WordWrap(call))

  def _HashBlocks(self, source, ranges): # pylint: disable=no-self-use
    data = source.ReadRangeSet(ranges)
    ctx = sha1()

    for p in data:
      ctx.update(p)

    return ctx.hexdigest()

  def _HashZeroBlocks(self, num_blocks): # pylint: disable=no-self-use
    """Return the hash value for all zero blocks."""
    zero_block = '\x00' * 4096
    ctx = sha1()
    for _ in range(num_blocks):
      ctx.update(zero_block)

    return ctx.hexdigest()

  # TODO(tbao): Due to http://b/20939131, block 0 may be changed without
  # remounting R/W. Will change the checking to a finer-grained way to
  # mask off those bits.
  def _CheckFirstBlock(self, script):
    r = rangelib.RangeSet((0, 1))
    srchash = self._HashBlocks(self.src, r)

    script.AppendExtra(('(range_sha1("%s", "%s") == "%s") || '
                        'abort("%s has been remounted R/W; '
                        'reflash device to reenable OTA updates");')
                       % (self.device, r.to_string_raw(), srchash,
                          self.device))

DataImage = blockimgdiff.DataImage


# map recovery.fstab's fs_types to mount/format "partition types"
PARTITION_TYPES = {
    "yaffs2": "MTD",
    "mtd": "MTD",
    "ext4": "EMMC",
    "emmc": "EMMC",
    "f2fs": "EMMC",
    "squashfs": "EMMC"
}

def GetTypeAndDevice(mount_point, info):
  fstab = info["fstab"]
  if fstab:
    return (PARTITION_TYPES[fstab[mount_point].fs_type],
            fstab[mount_point].device)
  else:
    raise KeyError


def ParseCertificate(data):
  """Parse a PEM-format certificate."""
  cert = []
  save = False
  for line in data.split("\n"):
    if "--END CERTIFICATE--" in line:
      break
    if save:
      cert.append(line)
    if "--BEGIN CERTIFICATE--" in line:
      save = True
  cert = "".join(cert).decode('base64')
  return cert

def MakeRecoveryPatch(input_dir, output_sink, recovery_img, boot_img,
                      info_dict=None):
  """Generate a binary patch that creates the recovery image starting
  with the boot image.  (Most of the space in these images is just the
  kernel, which is identical for the two, so the resulting patch
  should be efficient.)  Add it to the output zip, along with a shell
  script that is run from init.rc on first boot to actually do the
  patching and install the new recovery image.

  recovery_img and boot_img should be File objects for the
  corresponding images.  info should be the dictionary returned by
  common.LoadInfoDict() on the input target_files.
  """

  if info_dict is None:
    info_dict = OPTIONS.info_dict

  full_recovery_image = info_dict.get("full_recovery_image", None) == "true"
  system_root_image = info_dict.get("system_root_image", None) == "true"

  if full_recovery_image:
    output_sink("etc/recovery.img", recovery_img.data)

  else:
    diff_program = ["imgdiff"]
    path = os.path.join(input_dir, "SYSTEM", "etc", "recovery-resource.dat")
    if os.path.exists(path):
      diff_program.append("-b")
      diff_program.append(path)
      bonus_args = "-b /system/etc/recovery-resource.dat"
    else:
      bonus_args = ""

    d = Difference(recovery_img, boot_img, diff_program=diff_program)
    _, _, patch = d.ComputePatch()
    output_sink("recovery-from-boot.p", patch)

  try:
    boot_type, boot_device = GetTypeAndDevice("/boot", info_dict)
    recovery_type, recovery_device = GetTypeAndDevice("/recovery", info_dict)
  except KeyError:
    return

  if full_recovery_image:
    sh = """#!/system/bin/sh
if ! applypatch -c %(type)s:%(device)s:%(size)d:%(sha1)s; then
  applypatch /system/etc/recovery.img %(type)s:%(device)s %(sha1)s %(size)d && log -t recovery "Installing new recovery image: succeeded" || log -t recovery "Installing new recovery image: failed"
else
  log -t recovery "Recovery image already installed"
fi
""" % {'type': recovery_type,
       'device': recovery_device,
       'sha1': recovery_img.sha1,
       'size': recovery_img.size}
  else:
    sh = """#!/system/bin/sh
if ! applypatch -c %(recovery_type)s:%(recovery_device)s:%(recovery_size)d:%(recovery_sha1)s; then
  applypatch %(bonus_args)s %(boot_type)s:%(boot_device)s:%(boot_size)d:%(boot_sha1)s %(recovery_type)s:%(recovery_device)s %(recovery_sha1)s %(recovery_size)d %(boot_sha1)s:/system/recovery-from-boot.p && log -t recovery "Installing new recovery image: succeeded" || log -t recovery "Installing new recovery image: failed"
else
  log -t recovery "Recovery image already installed"
fi
""" % {'boot_size': boot_img.size,
       'boot_sha1': boot_img.sha1,
       'recovery_size': recovery_img.size,
       'recovery_sha1': recovery_img.sha1,
       'boot_type': boot_type,
       'boot_device': boot_device,
       'recovery_type': recovery_type,
       'recovery_device': recovery_device,
       'bonus_args': bonus_args}

  # The install script location moved from /system/etc to /system/bin
  # in the L release.  Parse init.*.rc files to find out where the
  # target-files expects it to be, and put it there.
  sh_location = "etc/install-recovery.sh"
  found = False
  if system_root_image:
    init_rc_dir = os.path.join(input_dir, "ROOT")
  else:
    init_rc_dir = os.path.join(input_dir, "BOOT", "RAMDISK")
  init_rc_files = os.listdir(init_rc_dir)
  for init_rc_file in init_rc_files:
    if (not init_rc_file.startswith('init.') or
        not init_rc_file.endswith('.rc')):
      continue

    with open(os.path.join(init_rc_dir, init_rc_file)) as f:
      for line in f:
        m = re.match(r"^service flash_recovery /system/(\S+)\s*$", line)
        if m:
          sh_location = m.group(1)
          found = True
          break

    if found:
      break

  print "putting script in", sh_location

  output_sink(sh_location, sh)