tools/releasetools/ota_from_target_files

#!/usr/bin/env python
#
# 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.

"""
Given a target-files zipfile, produces an OTA package that installs
that build.  An incremental OTA is produced if -i is given, otherwise
a full OTA is produced.

Usage:  ota_from_target_files [flags] input_target_files output_ota_package

  --board_config  <file>
      Deprecated.

  -k (--package_key) <key> Key to use to sign the package (default is
      the value of default_system_dev_certificate from the input
      target-files's META/misc_info.txt, or
      "build/target/product/security/testkey" if that value is not
      specified).

      For incremental OTAs, the default value is based on the source
      target-file, not the target build.

  -i  (--incremental_from)  <file>
      Generate an incremental OTA using the given target-files zip as
      the starting build.

  -v  (--verify)
      Remount and verify the checksums of the files written to the
      system and vendor (if used) partitions.  Incremental builds only.

  -o  (--oem_settings)  <file>
      Use the file to specify the expected OEM-specific properties
      on the OEM partition of the intended device.

  -w  (--wipe_user_data)
      Generate an OTA package that will wipe the user data partition
      when installed.

  -n  (--no_prereq)
      Omit the timestamp prereq check normally included at the top of
      the build scripts (used for developer OTA packages which
      legitimately need to go back and forth).

  -e  (--extra_script)  <file>
      Insert the contents of file at the end of the update script.

  -a  (--aslr_mode)  <on|off>
      Specify whether to turn on ASLR for the package (on by default).

  -2  (--two_step)
      Generate a 'two-step' OTA package, where recovery is updated
      first, so that any changes made to the system partition are done
      using the new recovery (new kernel, etc.).

  --block
      Generate a block-based OTA if possible.  Will fall back to a
      file-based OTA if the target_files is older and doesn't support
      block-based OTAs.

  -b  (--binary)  <file>
      Use the given binary as the update-binary in the output package,
      instead of the binary in the build's target_files.  Use for
      development only.

  -t  (--worker_threads) <int>
      Specifies the number of worker-threads that will be used when
      generating patches for incremental updates (defaults to 3).

"""

import sys

if sys.hexversion < 0x02070000:
  print >> sys.stderr, "Python 2.7 or newer is required."
  sys.exit(1)

import copy
import errno
import multiprocessing
import os
import re
import subprocess
import tempfile
import time
import zipfile

from hashlib import sha1 as sha1

import common
import edify_generator
import build_image
import blockimgdiff
import sparse_img

OPTIONS = common.OPTIONS
OPTIONS.package_key = None
OPTIONS.incremental_source = None
OPTIONS.verify = False
OPTIONS.require_verbatim = set()
OPTIONS.prohibit_verbatim = set(("system/build.prop",))
OPTIONS.patch_threshold = 0.95
OPTIONS.wipe_user_data = False
OPTIONS.omit_prereq = False
OPTIONS.extra_script = None
OPTIONS.aslr_mode = True
OPTIONS.worker_threads = multiprocessing.cpu_count() // 2
if OPTIONS.worker_threads == 0:
  OPTIONS.worker_threads = 1
OPTIONS.two_step = False
OPTIONS.no_signing = False
OPTIONS.block_based = False
OPTIONS.updater_binary = None
OPTIONS.oem_source = None
OPTIONS.fallback_to_full = True

def MostPopularKey(d, default):
  """Given a dict, return the key corresponding to the largest
  value.  Returns 'default' if the dict is empty."""
  x = [(v, k) for (k, v) in d.iteritems()]
  if not x: return default
  x.sort()
  return x[-1][1]


def IsSymlink(info):
  """Return true if the zipfile.ZipInfo object passed in represents a
  symlink."""
  return (info.external_attr >> 16) == 0120777

def IsRegular(info):
  """Return true if the zipfile.ZipInfo object passed in represents a
  symlink."""
  return (info.external_attr >> 28) == 010

def ClosestFileMatch(src, tgtfiles, existing):
  """Returns the closest file match between a source file and list
     of potential matches.  The exact filename match is preferred,
     then the sha1 is searched for, and finally a file with the same
     basename is evaluated.  Rename support in the updater-binary is
     required for the latter checks to be used."""

  result = tgtfiles.get("path:" + src.name)
  if result is not None:
    return result

  if not OPTIONS.target_info_dict.get("update_rename_support", False):
    return None

  if src.size < 1000:
    return None

  result = tgtfiles.get("sha1:" + src.sha1)
  if result is not None and existing.get(result.name) is None:
    return result
  result = tgtfiles.get("file:" + src.name.split("/")[-1])
  if result is not None and existing.get(result.name) is None:
    return result
  return None

class ItemSet:
  def __init__(self, partition, fs_config):
    self.partition = partition
    self.fs_config = fs_config
    self.ITEMS = {}

  def Get(self, name, dir=False):
    if name not in self.ITEMS:
      self.ITEMS[name] = Item(self, name, dir=dir)
    return self.ITEMS[name]

  def GetMetadata(self, input_zip):
    # The target_files contains a record of what the uid,
    # gid, and mode are supposed to be.
    output = input_zip.read(self.fs_config)

    for line in output.split("\n"):
      if not line: continue
      columns = line.split()
      name, uid, gid, mode = columns[:4]
      selabel = None
      capabilities = None

      # After the first 4 columns, there are a series of key=value
      # pairs. Extract out the fields we care about.
      for element in columns[4:]:
        key, value = element.split("=")
        if key == "selabel":
          selabel = value
        if key == "capabilities":
          capabilities = value

      i = self.ITEMS.get(name, None)
      if i is not None:
        i.uid = int(uid)
        i.gid = int(gid)
        i.mode = int(mode, 8)
        i.selabel = selabel
        i.capabilities = capabilities
        if i.dir:
          i.children.sort(key=lambda i: i.name)

    # set metadata for the files generated by this script.
    i = self.ITEMS.get("system/recovery-from-boot.p", None)
    if i: i.uid, i.gid, i.mode, i.selabel, i.capabilities = 0, 0, 0644, None, None
    i = self.ITEMS.get("system/etc/install-recovery.sh", None)
    if i: i.uid, i.gid, i.mode, i.selabel, i.capabilities = 0, 0, 0544, None, None


class Item:
  """Items represent the metadata (user, group, mode) of files and
  directories in the system image."""
  def __init__(self, itemset, name, dir=False):
    self.itemset = itemset
    self.name = name
    self.uid = None
    self.gid = None
    self.mode = None
    self.selabel = None
    self.capabilities = None
    self.dir = dir

    if name:
      self.parent = itemset.Get(os.path.dirname(name), dir=True)
      self.parent.children.append(self)
    else:
      self.parent = None
    if dir:
      self.children = []

  def Dump(self, indent=0):
    if self.uid is not None:
      print "%s%s %d %d %o" % ("  "*indent, self.name, self.uid, self.gid, self.mode)
    else:
      print "%s%s %s %s %s" % ("  "*indent, self.name, self.uid, self.gid, self.mode)
    if self.dir:
      print "%s%s" % ("  "*indent, self.descendants)
      print "%s%s" % ("  "*indent, self.best_subtree)
      for i in self.children:
        i.Dump(indent=indent+1)

  def CountChildMetadata(self):
    """Count up the (uid, gid, mode, selabel, capabilities) tuples for
    all children and determine the best strategy for using set_perm_recursive and
    set_perm to correctly chown/chmod all the files to their desired
    values.  Recursively calls itself for all descendants.

    Returns a dict of {(uid, gid, dmode, fmode, selabel, capabilities): count} counting up
    all descendants of this node.  (dmode or fmode may be None.)  Also
    sets the best_subtree of each directory Item to the (uid, gid,
    dmode, fmode, selabel, capabilities) tuple that will match the most
    descendants of that Item.
    """

    assert self.dir
    d = self.descendants = {(self.uid, self.gid, self.mode, None, self.selabel, self.capabilities): 1}
    for i in self.children:
      if i.dir:
        for k, v in i.CountChildMetadata().iteritems():
          d[k] = d.get(k, 0) + v
      else:
        k = (i.uid, i.gid, None, i.mode, i.selabel, i.capabilities)
        d[k] = d.get(k, 0) + 1

    # Find the (uid, gid, dmode, fmode, selabel, capabilities)
    # tuple that matches the most descendants.

    # First, find the (uid, gid) pair that matches the most
    # descendants.
    ug = {}
    for (uid, gid, _, _, _, _), count in d.iteritems():
      ug[(uid, gid)] = ug.get((uid, gid), 0) + count
    ug = MostPopularKey(ug, (0, 0))

    # Now find the dmode, fmode, selabel, and capabilities that match
    # the most descendants with that (uid, gid), and choose those.
    best_dmode = (0, 0755)
    best_fmode = (0, 0644)
    best_selabel = (0, None)
    best_capabilities = (0, None)
    for k, count in d.iteritems():
      if k[:2] != ug: continue
      if k[2] is not None and count >= best_dmode[0]: best_dmode = (count, k[2])
      if k[3] is not None and count >= best_fmode[0]: best_fmode = (count, k[3])
      if k[4] is not None and count >= best_selabel[0]: best_selabel = (count, k[4])
      if k[5] is not None and count >= best_capabilities[0]: best_capabilities = (count, k[5])
    self.best_subtree = ug + (best_dmode[1], best_fmode[1], best_selabel[1], best_capabilities[1])

    return d

  def SetPermissions(self, script):
    """Append set_perm/set_perm_recursive commands to 'script' to
    set all permissions, users, and groups for the tree of files
    rooted at 'self'."""

    self.CountChildMetadata()

    def recurse(item, current):
      # current is the (uid, gid, dmode, fmode, selabel, capabilities) tuple that the current
      # item (and all its children) have already been set to.  We only
      # need to issue set_perm/set_perm_recursive commands if we're
      # supposed to be something different.
      if item.dir:
        if current != item.best_subtree:
          script.SetPermissionsRecursive("/"+item.name, *item.best_subtree)
          current = item.best_subtree

        if item.uid != current[0] or item.gid != current[1] or \
           item.mode != current[2] or item.selabel != current[4] or \
           item.capabilities != current[5]:
          script.SetPermissions("/"+item.name, item.uid, item.gid,
                                item.mode, item.selabel, item.capabilities)

        for i in item.children:
          recurse(i, current)
      else:
        if item.uid != current[0] or item.gid != current[1] or \
               item.mode != current[3] or item.selabel != current[4] or \
               item.capabilities != current[5]:
          script.SetPermissions("/"+item.name, item.uid, item.gid,
                                item.mode, item.selabel, item.capabilities)

    recurse(self, (-1, -1, -1, -1, None, None))


def CopyPartitionFiles(itemset, input_zip, output_zip=None, substitute=None):
  """Copies files for the partition in the input zip to the output
  zip.  Populates the Item class with their metadata, and returns a
  list of symlinks.  output_zip may be None, in which case the copy is
  skipped (but the other side effects still happen).  substitute is an
  optional dict of {output filename: contents} to be output instead of
  certain input files.
  """

  symlinks = []

  partition = itemset.partition

  for info in input_zip.infolist():
    if info.filename.startswith(partition.upper() + "/"):
      basefilename = info.filename[7:]
      if IsSymlink(info):
        symlinks.append((input_zip.read(info.filename),
                         "/" + partition + "/" + basefilename))
      else:
        info2 = copy.copy(info)
        fn = info2.filename = partition + "/" + basefilename
        if substitute and fn in substitute and substitute[fn] is None:
          continue
        if output_zip is not None:
          if substitute and fn in substitute:
            data = substitute[fn]
          else:
            data = input_zip.read(info.filename)
          output_zip.writestr(info2, data)
        if fn.endswith("/"):
          itemset.Get(fn[:-1], dir=True)
        else:
          itemset.Get(fn, dir=False)

  symlinks.sort()
  return symlinks


def SignOutput(temp_zip_name, output_zip_name):
  key_passwords = common.GetKeyPasswords([OPTIONS.package_key])
  pw = key_passwords[OPTIONS.package_key]

  common.SignFile(temp_zip_name, output_zip_name, OPTIONS.package_key, pw,
                  whole_file=True)


def AppendAssertions(script, info_dict, oem_dict = None):
  oem_props = info_dict.get("oem_fingerprint_properties")
  if oem_props is None or len(oem_props) == 0:
    device = GetBuildProp("ro.product.device", info_dict)
    script.AssertDevice(device)
  else:
    if oem_dict is None:
      raise common.ExternalError("No OEM file provided to answer expected assertions")
    for prop in oem_props.split():
      if oem_dict.get(prop) is None:
        raise common.ExternalError("The OEM file is missing the property %s" % prop)
      script.AssertOemProperty(prop, oem_dict.get(prop))


def HasRecoveryPatch(target_files_zip):
  try:
    target_files_zip.getinfo("SYSTEM/recovery-from-boot.p")
    return True
  except KeyError:
    return False

def HasVendorPartition(target_files_zip):
  try:
    target_files_zip.getinfo("VENDOR/")
    return True
  except KeyError:
    return False

def GetOemProperty(name, oem_props, oem_dict, info_dict):
  if oem_props is not None and name in oem_props:
    return oem_dict[name]
  return GetBuildProp(name, info_dict)


def CalculateFingerprint(oem_props, oem_dict, info_dict):
  if oem_props is None:
    return GetBuildProp("ro.build.fingerprint", info_dict)
  return "%s/%s/%s:%s" % (
    GetOemProperty("ro.product.brand", oem_props, oem_dict, info_dict),
    GetOemProperty("ro.product.name", oem_props, oem_dict, info_dict),
    GetOemProperty("ro.product.device", oem_props, oem_dict, info_dict),
    GetBuildProp("ro.build.thumbprint", info_dict))


def GetImage(which, tmpdir, info_dict):
  # Return an image object (suitable for passing to BlockImageDiff)
  # for the 'which' partition (most be "system" or "vendor").  If a
  # prebuilt image and file map are found in tmpdir they are used,
  # otherwise they are reconstructed from the individual files.

  assert which in ("system", "vendor")

  path = os.path.join(tmpdir, "IMAGES", which + ".img")
  mappath = os.path.join(tmpdir, "IMAGES", which + ".map")
  if os.path.exists(path) and os.path.exists(mappath):
    print "using %s.img from target-files" % (which,)
    # This is a 'new' target-files, which already has the image in it.

  else:
    print "building %s.img from target-files" % (which,)

    # This is an 'old' target-files, which does not contain images
    # already built.  Build them.

    mappath = tempfile.mkstemp()[1]
    OPTIONS.tempfiles.append(mappath)

    import add_img_to_target_files
    if which == "system":
      path = add_img_to_target_files.BuildSystem(
          tmpdir, info_dict, block_list=mappath)
    elif which == "vendor":
      path = add_img_to_target_files.BuildVendor(
          tmpdir, info_dict, block_list=mappath)

  return sparse_img.SparseImage(path, mappath)


def WriteFullOTAPackage(input_zip, output_zip):
  # TODO: how to determine this?  We don't know what version it will
  # be installed on top of.  For now, we expect the API just won't
  # change very often.
  script = edify_generator.EdifyGenerator(3, OPTIONS.info_dict)

  oem_props = OPTIONS.info_dict.get("oem_fingerprint_properties")
  recovery_mount_options = OPTIONS.info_dict.get("recovery_mount_options")
  oem_dict = None
  if oem_props is not None and len(oem_props) > 0:
    if OPTIONS.oem_source is None:
      raise common.ExternalError("OEM source required for this build")
    script.Mount("/oem", recovery_mount_options)
    oem_dict = common.LoadDictionaryFromLines(open(OPTIONS.oem_source).readlines())

  metadata = {"post-build": CalculateFingerprint(
                               oem_props, oem_dict, OPTIONS.info_dict),
              "pre-device": GetOemProperty("ro.product.device", oem_props, oem_dict,
                                         OPTIONS.info_dict),
              "post-timestamp": GetBuildProp("ro.build.date.utc",
                                             OPTIONS.info_dict),
              }

  device_specific = common.DeviceSpecificParams(
      input_zip=input_zip,
      input_version=OPTIONS.info_dict["recovery_api_version"],
      output_zip=output_zip,
      script=script,
      input_tmp=OPTIONS.input_tmp,
      metadata=metadata,
      info_dict=OPTIONS.info_dict)

  has_recovery_patch = HasRecoveryPatch(input_zip)
  block_based = OPTIONS.block_based and has_recovery_patch

  if not OPTIONS.omit_prereq:
    ts = GetBuildProp("ro.build.date.utc", OPTIONS.info_dict)
    ts_text = GetBuildProp("ro.build.date", OPTIONS.info_dict)
    script.AssertOlderBuild(ts, ts_text)

  AppendAssertions(script, OPTIONS.info_dict, oem_dict)
  device_specific.FullOTA_Assertions()

  # Two-step package strategy (in chronological order, which is *not*
  # the order in which the generated script has things):
  #
  # if stage is not "2/3" or "3/3":
  #    write recovery image to boot partition
  #    set stage to "2/3"
  #    reboot to boot partition and restart recovery
  # else if stage is "2/3":
  #    write recovery image to recovery partition
  #    set stage to "3/3"
  #    reboot to recovery partition and restart recovery
  # else:
  #    (stage must be "3/3")
  #    set stage to ""
  #    do normal full package installation:
  #       wipe and install system, boot image, etc.
  #       set up system to update recovery partition on first boot
  #    complete script normally (allow recovery to mark itself finished and reboot)

  recovery_img = common.GetBootableImage("recovery.img", "recovery.img",
                                         OPTIONS.input_tmp, "RECOVERY")
  if OPTIONS.two_step:
    if not OPTIONS.info_dict.get("multistage_support", None):
      assert False, "two-step packages not supported by this build"
    fs = OPTIONS.info_dict["fstab"]["/misc"]
    assert fs.fs_type.upper() == "EMMC", \
        "two-step packages only supported on devices with EMMC /misc partitions"
    bcb_dev = {"bcb_dev": fs.device}
    common.ZipWriteStr(output_zip, "recovery.img", recovery_img.data)
    script.AppendExtra("""
if get_stage("%(bcb_dev)s") == "2/3" then
""" % bcb_dev)
    script.WriteRawImage("/recovery", "recovery.img")
    script.AppendExtra("""
set_stage("%(bcb_dev)s", "3/3");
reboot_now("%(bcb_dev)s", "recovery");
else if get_stage("%(bcb_dev)s") == "3/3" then
""" % bcb_dev)

  device_specific.FullOTA_InstallBegin()

  system_progress = 0.75

  if OPTIONS.wipe_user_data:
    system_progress -= 0.1
  if HasVendorPartition(input_zip):
    system_progress -= 0.1

  if "selinux_fc" in OPTIONS.info_dict:
    WritePolicyConfig(OPTIONS.info_dict["selinux_fc"], output_zip)

  recovery_mount_options = OPTIONS.info_dict.get("recovery_mount_options")

  system_items = ItemSet("system", "META/filesystem_config.txt")
  script.ShowProgress(system_progress, 0)

  if block_based:
    # Full OTA is done as an "incremental" against an empty source
    # image.  This has the effect of writing new data from the package
    # to the entire partition, but lets us reuse the updater code that
    # writes incrementals to do it.
    system_tgt = GetImage("system", OPTIONS.input_tmp, OPTIONS.info_dict)
    system_tgt.ResetFileMap()
    system_diff = common.BlockDifference("system", system_tgt, src=None)
    system_diff.WriteScript(script, output_zip)
  else:
    script.FormatPartition("/system")
    script.Mount("/system", recovery_mount_options)
    if not has_recovery_patch:
      script.UnpackPackageDir("recovery", "/system")
    script.UnpackPackageDir("system", "/system")

    symlinks = CopyPartitionFiles(system_items, input_zip, output_zip)
    script.MakeSymlinks(symlinks)

  boot_img = common.GetBootableImage("boot.img", "boot.img",
                                     OPTIONS.input_tmp, "BOOT")

  if not block_based:
    def output_sink(fn, data):
      common.ZipWriteStr(output_zip, "recovery/" + fn, data)
      system_items.Get("system/" + fn, dir=False)

    common.MakeRecoveryPatch(OPTIONS.input_tmp, output_sink,
                             recovery_img, boot_img)

    system_items.GetMetadata(input_zip)
    system_items.Get("system").SetPermissions(script)

  if HasVendorPartition(input_zip):
    vendor_items = ItemSet("vendor", "META/vendor_filesystem_config.txt")
    script.ShowProgress(0.1, 0)

    if block_based:
      vendor_tgt = GetImage("vendor", OPTIONS.input_tmp, OPTIONS.info_dict)
      vendor_tgt.ResetFileMap()
      vendor_diff = common.BlockDifference("vendor", vendor_tgt)
      vendor_diff.WriteScript(script, output_zip)
    else:
      script.FormatPartition("/vendor")
      script.Mount("/vendor", recovery_mount_options)
      script.UnpackPackageDir("vendor", "/vendor")

      symlinks = CopyPartitionFiles(vendor_items, input_zip, output_zip)
      script.MakeSymlinks(symlinks)

      vendor_items.GetMetadata(input_zip)
      vendor_items.Get("vendor").SetPermissions(script)

  common.CheckSize(boot_img.data, "boot.img", OPTIONS.info_dict)
  common.ZipWriteStr(output_zip, "boot.img", boot_img.data)

  script.ShowProgress(0.05, 5)
  script.WriteRawImage("/boot", "boot.img")

  script.ShowProgress(0.2, 10)
  device_specific.FullOTA_InstallEnd()

  if OPTIONS.extra_script is not None:
    script.AppendExtra(OPTIONS.extra_script)

  script.UnmountAll()

  if OPTIONS.wipe_user_data:
    script.ShowProgress(0.1, 10)
    script.FormatPartition("/data")

  if OPTIONS.two_step:
    script.AppendExtra("""
set_stage("%(bcb_dev)s", "");
""" % bcb_dev)
    script.AppendExtra("else\n")
    script.WriteRawImage("/boot", "recovery.img")
    script.AppendExtra("""
set_stage("%(bcb_dev)s", "2/3");
reboot_now("%(bcb_dev)s", "");
endif;
endif;
""" % bcb_dev)
  script.AddToZip(input_zip, output_zip, input_path=OPTIONS.updater_binary)
  WriteMetadata(metadata, output_zip)


def WritePolicyConfig(file_name, output_zip):
  common.ZipWrite(output_zip, file_name, os.path.basename(file_name))


def WriteMetadata(metadata, output_zip):
  common.ZipWriteStr(output_zip, "META-INF/com/android/metadata",
                     "".join(["%s=%s\n" % kv
                              for kv in sorted(metadata.iteritems())]))


def LoadPartitionFiles(z, partition):
  """Load all the files from the given partition in a given target-files
  ZipFile, and return a dict of {filename: File object}."""
  out = {}
  prefix = partition.upper() + "/"
  for info in z.infolist():
    if info.filename.startswith(prefix) and not IsSymlink(info):
      basefilename = info.filename[7:]
      fn = partition + "/" + basefilename
      data = z.read(info.filename)
      out[fn] = common.File(fn, data)
  return out


def GetBuildProp(prop, info_dict):
  """Return the fingerprint of the build of a given target-files info_dict."""
  try:
    return info_dict.get("build.prop", {})[prop]
  except KeyError:
    raise common.ExternalError("couldn't find %s in build.prop" % (prop,))


def AddToKnownPaths(filename, known_paths):
  if filename[-1] == "/":
    return
  dirs = filename.split("/")[:-1]
  while len(dirs) > 0:
    path = "/".join(dirs)
    if path in known_paths:
      break;
    known_paths.add(path)
    dirs.pop()


def WriteBlockIncrementalOTAPackage(target_zip, source_zip, output_zip):
  source_version = OPTIONS.source_info_dict["recovery_api_version"]
  target_version = OPTIONS.target_info_dict["recovery_api_version"]

  if source_version == 0:
    print ("WARNING: generating edify script for a source that "
           "can't install it.")
  script = edify_generator.EdifyGenerator(source_version,
                                          OPTIONS.target_info_dict)

  metadata = {"pre-device": GetBuildProp("ro.product.device",
                                         OPTIONS.source_info_dict),
              "post-timestamp": GetBuildProp("ro.build.date.utc",
                                             OPTIONS.target_info_dict),
              }

  device_specific = common.DeviceSpecificParams(
      source_zip=source_zip,
      source_version=source_version,
      target_zip=target_zip,
      target_version=target_version,
      output_zip=output_zip,
      script=script,
      metadata=metadata,
      info_dict=OPTIONS.info_dict)

  source_fp = GetBuildProp("ro.build.fingerprint", OPTIONS.source_info_dict)
  target_fp = GetBuildProp("ro.build.fingerprint", OPTIONS.target_info_dict)
  metadata["pre-build"] = source_fp
  metadata["post-build"] = target_fp

  source_boot = common.GetBootableImage(
      "/tmp/boot.img", "boot.img", OPTIONS.source_tmp, "BOOT",
      OPTIONS.source_info_dict)
  target_boot = common.GetBootableImage(
      "/tmp/boot.img", "boot.img", OPTIONS.target_tmp, "BOOT")
  updating_boot = (not OPTIONS.two_step and
                   (source_boot.data != target_boot.data))

  source_recovery = common.GetBootableImage(
      "/tmp/recovery.img", "recovery.img", OPTIONS.source_tmp, "RECOVERY",
      OPTIONS.source_info_dict)
  target_recovery = common.GetBootableImage(
      "/tmp/recovery.img", "recovery.img", OPTIONS.target_tmp, "RECOVERY")
  updating_recovery = (source_recovery.data != target_recovery.data)

  system_src = GetImage("system", OPTIONS.source_tmp, OPTIONS.source_info_dict)
  system_tgt = GetImage("system", OPTIONS.target_tmp, OPTIONS.target_info_dict)

  blockimgdiff_version = 1
  if OPTIONS.info_dict:
    blockimgdiff_version = max(
        int(i) for i in
        OPTIONS.info_dict.get("blockimgdiff_versions", "1").split(","))

  system_diff = common.BlockDifference("system", system_tgt, system_src,
                                       check_first_block=True,
                                       version=blockimgdiff_version)

  if HasVendorPartition(target_zip):
    if not HasVendorPartition(source_zip):
      raise RuntimeError("can't generate incremental that adds /vendor")
    vendor_src = GetImage("vendor", OPTIONS.source_tmp, OPTIONS.source_info_dict)
    vendor_tgt = GetImage("vendor", OPTIONS.target_tmp, OPTIONS.target_info_dict)
    vendor_diff = common.BlockDifference("vendor", vendor_tgt, vendor_src,
                                         check_first_block=True,
                                         version=blockimgdiff_version)
  else:
    vendor_diff = None

  oem_props = OPTIONS.target_info_dict.get("oem_fingerprint_properties")
  recovery_mount_options = OPTIONS.target_info_dict.get("recovery_mount_options")
  oem_dict = None
  if oem_props is not None and len(oem_props) > 0:
    if OPTIONS.oem_source is None:
      raise common.ExternalError("OEM source required for this build")
    script.Mount("/oem", recovery_mount_options)
    oem_dict = common.LoadDictionaryFromLines(open(OPTIONS.oem_source).readlines())

  AppendAssertions(script, OPTIONS.target_info_dict, oem_dict)
  device_specific.IncrementalOTA_Assertions()

  # Two-step incremental package strategy (in chronological order,
  # which is *not* the order in which the generated script has
  # things):
  #
  # if stage is not "2/3" or "3/3":
  #    do verification on current system
  #    write recovery image to boot partition
  #    set stage to "2/3"
  #    reboot to boot partition and restart recovery
  # else if stage is "2/3":
  #    write recovery image to recovery partition
  #    set stage to "3/3"
  #    reboot to recovery partition and restart recovery
  # else:
  #    (stage must be "3/3")
  #    perform update:
  #       patch system files, etc.
  #       force full install of new boot image
  #       set up system to update recovery partition on first boot
  #    complete script normally (allow recovery to mark itself finished and reboot)

  if OPTIONS.two_step:
    if not OPTIONS.info_dict.get("multistage_support", None):
      assert False, "two-step packages not supported by this build"
    fs = OPTIONS.info_dict["fstab"]["/misc"]
    assert fs.fs_type.upper() == "EMMC", \
        "two-step packages only supported on devices with EMMC /misc partitions"
    bcb_dev = {"bcb_dev": fs.device}
    common.ZipWriteStr(output_zip, "recovery.img", target_recovery.data)
    script.AppendExtra("""
if get_stage("%(bcb_dev)s") == "2/3" then
""" % bcb_dev)
    script.AppendExtra("sleep(20);\n");
    script.WriteRawImage("/recovery", "recovery.img")
    script.AppendExtra("""
set_stage("%(bcb_dev)s", "3/3");
reboot_now("%(bcb_dev)s", "recovery");
else if get_stage("%(bcb_dev)s") != "3/3" then
""" % bcb_dev)

  script.Print("Verifying current system...")

  device_specific.IncrementalOTA_VerifyBegin()

  if oem_props is None:
    # When blockimgdiff version is less than 3 (non-resumable block-based OTA),
    # patching on a device that's already on the target build will damage the
    # system. Because operations like move don't check the block state, they
    # always apply the changes unconditionally.
    if blockimgdiff_version <= 2:
      script.AssertSomeFingerprint(source_fp)
    else:
      script.AssertSomeFingerprint(source_fp, target_fp)
  else:
    if blockimgdiff_version <= 2:
      script.AssertSomeThumbprint(
          GetBuildProp("ro.build.thumbprint", OPTIONS.source_info_dict))
    else:
      script.AssertSomeThumbprint(
          GetBuildProp("ro.build.thumbprint", OPTIONS.target_info_dict),
          GetBuildProp("ro.build.thumbprint", OPTIONS.source_info_dict))

  if updating_boot:
    boot_type, boot_device = common.GetTypeAndDevice("/boot", OPTIONS.info_dict)
    d = common.Difference(target_boot, source_boot)
    _, _, d = d.ComputePatch()
    if d is None:
      include_full_boot = True
      common.ZipWriteStr(output_zip, "boot.img", target_boot.data)
    else:
      include_full_boot = False

      print "boot      target: %d  source: %d  diff: %d" % (
          target_boot.size, source_boot.size, len(d))

      common.ZipWriteStr(output_zip, "patch/boot.img.p", d)

      script.PatchCheck("%s:%s:%d:%s:%d:%s" %
                        (boot_type, boot_device,
                         source_boot.size, source_boot.sha1,
                         target_boot.size, target_boot.sha1))

  device_specific.IncrementalOTA_VerifyEnd()

  if OPTIONS.two_step:
    script.WriteRawImage("/boot", "recovery.img")
    script.AppendExtra("""
set_stage("%(bcb_dev)s", "2/3");
reboot_now("%(bcb_dev)s", "");
else
""" % bcb_dev)

  # Verify the existing partitions.
  system_diff.WriteVerifyScript(script)
  if vendor_diff:
    vendor_diff.WriteVerifyScript(script)

  script.Comment("---- start making changes here ----")

  device_specific.IncrementalOTA_InstallBegin()

  system_diff.WriteScript(script, output_zip,
                          progress=0.8 if vendor_diff else 0.9)
  if vendor_diff:
    vendor_diff.WriteScript(script, output_zip, progress=0.1)

  if OPTIONS.two_step:
    common.ZipWriteStr(output_zip, "boot.img", target_boot.data)
    script.WriteRawImage("/boot", "boot.img")
    print "writing full boot image (forced by two-step mode)"

  if not OPTIONS.two_step:
    if updating_boot:
      if include_full_boot:
        print "boot image changed; including full."
        script.Print("Installing boot image...")
        script.WriteRawImage("/boot", "boot.img")
      else:
        # Produce the boot image by applying a patch to the current
        # contents of the boot partition, and write it back to the
        # partition.
        print "boot image changed; including patch."
        script.Print("Patching boot image...")
        script.ShowProgress(0.1, 10)
        script.ApplyPatch("%s:%s:%d:%s:%d:%s"
                          % (boot_type, boot_device,
                             source_boot.size, source_boot.sha1,
                             target_boot.size, target_boot.sha1),
                          "-",
                          target_boot.size, target_boot.sha1,
                          source_boot.sha1, "patch/boot.img.p")
    else:
      print "boot image unchanged; skipping."

  # Do device-specific installation (eg, write radio image).
  device_specific.IncrementalOTA_InstallEnd()

  if OPTIONS.extra_script is not None:
    script.AppendExtra(OPTIONS.extra_script)

  if OPTIONS.wipe_user_data:
    script.Print("Erasing user data...")
    script.FormatPartition("/data")

  if OPTIONS.two_step:
    script.AppendExtra("""
set_stage("%(bcb_dev)s", "");
endif;
endif;
""" % bcb_dev)

  script.SetProgress(1)
  script.AddToZip(target_zip, output_zip, input_path=OPTIONS.updater_binary)
  WriteMetadata(metadata, output_zip)


class FileDifference:
  def __init__(self, partition, source_zip, target_zip, output_zip):
    print "Loading target..."
    self.target_data = target_data = LoadPartitionFiles(target_zip, partition)
    print "Loading source..."
    self.source_data = source_data = LoadPartitionFiles(source_zip, partition)

    self.verbatim_targets = verbatim_targets = []
    self.patch_list = patch_list = []
    diffs = []
    self.renames = renames = {}
    known_paths = set()
    largest_source_size = 0

    matching_file_cache = {}
    for fn, sf in source_data.items():
      assert fn == sf.name
      matching_file_cache["path:" + fn] = sf
      if fn in target_data.keys():
        AddToKnownPaths(fn, known_paths)
      # Only allow eligibility for filename/sha matching
      # if there isn't a perfect path match.
      if target_data.get(sf.name) is None:
        matching_file_cache["file:" + fn.split("/")[-1]] = sf
        matching_file_cache["sha:" + sf.sha1] = sf

    for fn in sorted(target_data.keys()):
      tf = target_data[fn]
      assert fn == tf.name
      sf = ClosestFileMatch(tf, matching_file_cache, renames)
      if sf is not None and sf.name != tf.name:
        print "File has moved from " + sf.name + " to " + tf.name
        renames[sf.name] = tf

      if sf is None or fn in OPTIONS.require_verbatim:
        # This file should be included verbatim
        if fn in OPTIONS.prohibit_verbatim:
          raise common.ExternalError("\"%s\" must be sent verbatim" % (fn,))
        print "send", fn, "verbatim"
        tf.AddToZip(output_zip)
        verbatim_targets.append((fn, tf.size, tf.sha1))
        if fn in target_data.keys():
          AddToKnownPaths(fn, known_paths)
      elif tf.sha1 != sf.sha1:
        # File is different; consider sending as a patch
        diffs.append(common.Difference(tf, sf))
      else:
        # Target file data identical to source (may still be renamed)
        pass

    common.ComputeDifferences(diffs)

    for diff in diffs:
      tf, sf, d = diff.GetPatch()
      path = "/".join(tf.name.split("/")[:-1])
      if d is None or len(d) > tf.size * OPTIONS.patch_threshold or \
          path not in known_paths:
        # patch is almost as big as the file; don't bother patching
        # or a patch + rename cannot take place due to the target
        # directory not existing
        tf.AddToZip(output_zip)
        verbatim_targets.append((tf.name, tf.size, tf.sha1))
        if sf.name in renames:
          del renames[sf.name]
        AddToKnownPaths(tf.name, known_paths)
      else:
        common.ZipWriteStr(output_zip, "patch/" + sf.name + ".p", d)
        patch_list.append((tf, sf, tf.size, common.sha1(d).hexdigest()))
        largest_source_size = max(largest_source_size, sf.size)

    self.largest_source_size = largest_source_size

  def EmitVerification(self, script):
    so_far = 0
    for tf, sf, size, patch_sha in self.patch_list:
      if tf.name != sf.name:
        script.SkipNextActionIfTargetExists(tf.name, tf.sha1)
      script.PatchCheck("/"+sf.name, tf.sha1, sf.sha1)
      so_far += sf.size
    return so_far

  def EmitExplicitTargetVerification(self, script):
    for fn, size, sha1 in self.verbatim_targets:
      if (fn[-1] != "/"):
        script.FileCheck("/"+fn, sha1)
    for tf, _, _, _ in self.patch_list:
      script.FileCheck(tf.name, tf.sha1)

  def RemoveUnneededFiles(self, script, extras=()):
    script.DeleteFiles(["/"+i[0] for i in self.verbatim_targets] +
                       ["/"+i for i in sorted(self.source_data)
                              if i not in self.target_data and
                              i not in self.renames] +
                       list(extras))

  def TotalPatchSize(self):
    return sum(i[1].size for i in self.patch_list)

  def EmitPatches(self, script, total_patch_size, so_far):
    self.deferred_patch_list = deferred_patch_list = []
    for item in self.patch_list:
      tf, sf, size, _ = item
      if tf.name == "system/build.prop":
        deferred_patch_list.append(item)
        continue
      if (sf.name != tf.name):
        script.SkipNextActionIfTargetExists(tf.name, tf.sha1)
      script.ApplyPatch("/"+sf.name, "-", tf.size, tf.sha1, sf.sha1, "patch/"+sf.name+".p")
      so_far += tf.size
      script.SetProgress(so_far / total_patch_size)
    return so_far

  def EmitDeferredPatches(self, script):
    for item in self.deferred_patch_list:
      tf, sf, size, _ = item
      script.ApplyPatch("/"+sf.name, "-", tf.size, tf.sha1, sf.sha1, "patch/"+sf.name+".p")
    script.SetPermissions("/system/build.prop", 0, 0, 0644, None, None)

  def EmitRenames(self, script):
    if len(self.renames) > 0:
      script.Print("Renaming files...")
      for src, tgt in self.renames.iteritems():
        print "Renaming " + src + " to " + tgt.name
        script.RenameFile(src, tgt.name)




def WriteIncrementalOTAPackage(target_zip, source_zip, output_zip):
  target_has_recovery_patch = HasRecoveryPatch(target_zip)
  source_has_recovery_patch = HasRecoveryPatch(source_zip)

  if (OPTIONS.block_based and
      target_has_recovery_patch and
      source_has_recovery_patch):
    return WriteBlockIncrementalOTAPackage(target_zip, source_zip, output_zip)

  source_version = OPTIONS.source_info_dict["recovery_api_version"]
  target_version = OPTIONS.target_info_dict["recovery_api_version"]

  if source_version == 0:
    print ("WARNING: generating edify script for a source that "
           "can't install it.")
  script = edify_generator.EdifyGenerator(source_version,
                                          OPTIONS.target_info_dict)

  oem_props = OPTIONS.info_dict.get("oem_fingerprint_properties")
  recovery_mount_options = OPTIONS.info_dict.get("recovery_mount_options")
  oem_dict = None
  if oem_props is not None and len(oem_props) > 0:
    if OPTIONS.oem_source is None:
      raise common.ExternalError("OEM source required for this build")
    script.Mount("/oem", recovery_mount_options)
    oem_dict = common.LoadDictionaryFromLines(open(OPTIONS.oem_source).readlines())

  metadata = {"pre-device": GetOemProperty("ro.product.device", oem_props, oem_dict,
                                         OPTIONS.source_info_dict),
              "post-timestamp": GetBuildProp("ro.build.date.utc",
                                             OPTIONS.target_info_dict),
              }

  device_specific = common.DeviceSpecificParams(
      source_zip=source_zip,
      source_version=source_version,
      target_zip=target_zip,
      target_version=target_version,
      output_zip=output_zip,
      script=script,
      metadata=metadata,
      info_dict=OPTIONS.info_dict)

  system_diff = FileDifference("system", source_zip, target_zip, output_zip)
  script.Mount("/system", recovery_mount_options)
  if HasVendorPartition(target_zip):
    vendor_diff = FileDifference("vendor", source_zip, target_zip, output_zip)
    script.Mount("/vendor", recovery_mount_options)
  else:
    vendor_diff = None

  target_fp = CalculateFingerprint(oem_props, oem_dict, OPTIONS.target_info_dict)
  source_fp = CalculateFingerprint(oem_props, oem_dict, OPTIONS.source_info_dict)

  if oem_props is None:
    script.AssertSomeFingerprint(source_fp, target_fp)
  else:
    script.AssertSomeThumbprint(
        GetBuildProp("ro.build.thumbprint", OPTIONS.target_info_dict),
        GetBuildProp("ro.build.thumbprint", OPTIONS.source_info_dict))

  metadata["pre-build"] = source_fp
  metadata["post-build"] = target_fp

  source_boot = common.GetBootableImage(
      "/tmp/boot.img", "boot.img", OPTIONS.source_tmp, "BOOT",
      OPTIONS.source_info_dict)
  target_boot = common.GetBootableImage(
      "/tmp/boot.img", "boot.img", OPTIONS.target_tmp, "BOOT")
  updating_boot = (not OPTIONS.two_step and
                   (source_boot.data != target_boot.data))

  source_recovery = common.GetBootableImage(
      "/tmp/recovery.img", "recovery.img", OPTIONS.source_tmp, "RECOVERY",
      OPTIONS.source_info_dict)
  target_recovery = common.GetBootableImage(
      "/tmp/recovery.img", "recovery.img", OPTIONS.target_tmp, "RECOVERY")
  updating_recovery = (source_recovery.data != target_recovery.data)

  # Here's how we divide up the progress bar:
  #  0.1 for verifying the start state (PatchCheck calls)
  #  0.8 for applying patches (ApplyPatch calls)
  #  0.1 for unpacking verbatim files, symlinking, and doing the
  #      device-specific commands.

  AppendAssertions(script, OPTIONS.target_info_dict, oem_dict)
  device_specific.IncrementalOTA_Assertions()

  # Two-step incremental package strategy (in chronological order,
  # which is *not* the order in which the generated script has
  # things):
  #
  # if stage is not "2/3" or "3/3":
  #    do verification on current system
  #    write recovery image to boot partition
  #    set stage to "2/3"
  #    reboot to boot partition and restart recovery
  # else if stage is "2/3":
  #    write recovery image to recovery partition
  #    set stage to "3/3"
  #    reboot to recovery partition and restart recovery
  # else:
  #    (stage must be "3/3")
  #    perform update:
  #       patch system files, etc.
  #       force full install of new boot image
  #       set up system to update recovery partition on first boot
  #    complete script normally (allow recovery to mark itself finished and reboot)

  if OPTIONS.two_step:
    if not OPTIONS.info_dict.get("multistage_support", None):
      assert False, "two-step packages not supported by this build"
    fs = OPTIONS.info_dict["fstab"]["/misc"]
    assert fs.fs_type.upper() == "EMMC", \
        "two-step packages only supported on devices with EMMC /misc partitions"
    bcb_dev = {"bcb_dev": fs.device}
    common.ZipWriteStr(output_zip, "recovery.img", target_recovery.data)
    script.AppendExtra("""
if get_stage("%(bcb_dev)s") == "2/3" then
""" % bcb_dev)
    script.AppendExtra("sleep(20);\n");
    script.WriteRawImage("/recovery", "recovery.img")
    script.AppendExtra("""
set_stage("%(bcb_dev)s", "3/3");
reboot_now("%(bcb_dev)s", "recovery");
else if get_stage("%(bcb_dev)s") != "3/3" then
""" % bcb_dev)

  script.Print("Verifying current system...")

  device_specific.IncrementalOTA_VerifyBegin()

  script.ShowProgress(0.1, 0)
  so_far = system_diff.EmitVerification(script)
  if vendor_diff:
    so_far += vendor_diff.EmitVerification(script)

  if updating_boot:
    d = common.Difference(target_boot, source_boot)
    _, _, d = d.ComputePatch()
    print "boot      target: %d  source: %d  diff: %d" % (
        target_boot.size, source_boot.size, len(d))

    common.ZipWriteStr(output_zip, "patch/boot.img.p", d)

    boot_type, boot_device = common.GetTypeAndDevice("/boot", OPTIONS.info_dict)

    script.PatchCheck("%s:%s:%d:%s:%d:%s" %
                      (boot_type, boot_device,
                       source_boot.size, source_boot.sha1,
                       target_boot.size, target_boot.sha1))
    so_far += source_boot.size

  size = []
  if system_diff.patch_list: size.append(system_diff.largest_source_size)
  if vendor_diff:
    if vendor_diff.patch_list: size.append(vendor_diff.largest_source_size)
  if size or updating_recovery or updating_boot:
    script.CacheFreeSpaceCheck(max(size))

  device_specific.IncrementalOTA_VerifyEnd()

  if OPTIONS.two_step:
    script.WriteRawImage("/boot", "recovery.img")
    script.AppendExtra("""
set_stage("%(bcb_dev)s", "2/3");
reboot_now("%(bcb_dev)s", "");
else
""" % bcb_dev)

  script.Comment("---- start making changes here ----")

  device_specific.IncrementalOTA_InstallBegin()

  if OPTIONS.two_step:
    common.ZipWriteStr(output_zip, "boot.img", target_boot.data)
    script.WriteRawImage("/boot", "boot.img")
    print "writing full boot image (forced by two-step mode)"

  script.Print("Removing unneeded files...")
  system_diff.RemoveUnneededFiles(script, ("/system/recovery.img",))
  if vendor_diff:
    vendor_diff.RemoveUnneededFiles(script)

  script.ShowProgress(0.8, 0)
  total_patch_size = 1.0 + system_diff.TotalPatchSize()
  if vendor_diff:
    total_patch_size += vendor_diff.TotalPatchSize()
  if updating_boot:
    total_patch_size += target_boot.size

  script.Print("Patching system files...")
  so_far = system_diff.EmitPatches(script, total_patch_size, 0)
  if vendor_diff:
    script.Print("Patching vendor files...")
    so_far = vendor_diff.EmitPatches(script, total_patch_size, so_far)

  if not OPTIONS.two_step:
    if updating_boot:
      # Produce the boot image by applying a patch to the current
      # contents of the boot partition, and write it back to the
      # partition.
      script.Print("Patching boot image...")
      script.ApplyPatch("%s:%s:%d:%s:%d:%s"
                        % (boot_type, boot_device,
                           source_boot.size, source_boot.sha1,
                           target_boot.size, target_boot.sha1),
                        "-",
                        target_boot.size, target_boot.sha1,
                        source_boot.sha1, "patch/boot.img.p")
      so_far += target_boot.size
      script.SetProgress(so_far / total_patch_size)
      print "boot image changed; including."
    else:
      print "boot image unchanged; skipping."

  system_items = ItemSet("system", "META/filesystem_config.txt")
  if vendor_diff:
    vendor_items = ItemSet("vendor", "META/vendor_filesystem_config.txt")

  if updating_recovery:
    # Recovery is generated as a patch using both the boot image
    # (which contains the same linux kernel as recovery) and the file
    # /system/etc/recovery-resource.dat (which contains all the images
    # used in the recovery UI) as sources.  This lets us minimize the
    # size of the patch, which must be included in every OTA package.
    #
    # For older builds where recovery-resource.dat is not present, we
    # use only the boot image as the source.

    if not target_has_recovery_patch:
      def output_sink(fn, data):
        common.ZipWriteStr(output_zip, "recovery/" + fn, data)
        system_items.Get("system/" + fn, dir=False)

      common.MakeRecoveryPatch(OPTIONS.target_tmp, output_sink,
                               target_recovery, target_boot)
      script.DeleteFiles(["/system/recovery-from-boot.p",
                          "/system/etc/install-recovery.sh"])
    print "recovery image changed; including as patch from boot."
  else:
    print "recovery image unchanged; skipping."

  script.ShowProgress(0.1, 10)

  target_symlinks = CopyPartitionFiles(system_items, target_zip, None)
  if vendor_diff:
    target_symlinks.extend(CopyPartitionFiles(vendor_items, target_zip, None))

  temp_script = script.MakeTemporary()
  system_items.GetMetadata(target_zip)
  system_items.Get("system").SetPermissions(temp_script)
  if vendor_diff:
    vendor_items.GetMetadata(target_zip)
    vendor_items.Get("vendor").SetPermissions(temp_script)

  # Note that this call will mess up the trees of Items, so make sure
  # we're done with them.
  source_symlinks = CopyPartitionFiles(system_items, source_zip, None)
  if vendor_diff:
    source_symlinks.extend(CopyPartitionFiles(vendor_items, source_zip, None))

  target_symlinks_d = dict([(i[1], i[0]) for i in target_symlinks])
  source_symlinks_d = dict([(i[1], i[0]) for i in source_symlinks])

  # Delete all the symlinks in source that aren't in target.  This
  # needs to happen before verbatim files are unpacked, in case a
  # symlink in the source is replaced by a real file in the target.
  to_delete = []
  for dest, link in source_symlinks:
    if link not in target_symlinks_d:
      to_delete.append(link)
  script.DeleteFiles(to_delete)

  if system_diff.verbatim_targets:
    script.Print("Unpacking new system files...")
    script.UnpackPackageDir("system", "/system")
  if vendor_diff and vendor_diff.verbatim_targets:
    script.Print("Unpacking new vendor files...")
    script.UnpackPackageDir("vendor", "/vendor")

  if updating_recovery and not target_has_recovery_patch:
    script.Print("Unpacking new recovery...")
    script.UnpackPackageDir("recovery", "/system")

  system_diff.EmitRenames(script)
  if vendor_diff:
    vendor_diff.EmitRenames(script)

  script.Print("Symlinks and permissions...")

  # Create all the symlinks that don't already exist, or point to
  # somewhere different than what we want.  Delete each symlink before
  # creating it, since the 'symlink' command won't overwrite.
  to_create = []
  for dest, link in target_symlinks:
    if link in source_symlinks_d:
      if dest != source_symlinks_d[link]:
        to_create.append((dest, link))
    else:
      to_create.append((dest, link))
  script.DeleteFiles([i[1] for i in to_create])
  script.MakeSymlinks(to_create)

  # Now that the symlinks are created, we can set all the
  # permissions.
  script.AppendScript(temp_script)

  # Do device-specific installation (eg, write radio image).
  device_specific.IncrementalOTA_InstallEnd()

  if OPTIONS.extra_script is not None:
    script.AppendExtra(OPTIONS.extra_script)

  # Patch the build.prop file last, so if something fails but the
  # device can still come up, it appears to be the old build and will
  # get set the OTA package again to retry.
  script.Print("Patching remaining system files...")
  system_diff.EmitDeferredPatches(script)

  if OPTIONS.wipe_user_data:
    script.Print("Erasing user data...")
    script.FormatPartition("/data")

  if OPTIONS.two_step:
    script.AppendExtra("""
set_stage("%(bcb_dev)s", "");
endif;
endif;
""" % bcb_dev)

  if OPTIONS.verify and system_diff:
    script.Print("Remounting and verifying system partition files...")
    script.Unmount("/system")
    script.Mount("/system")
    system_diff.EmitExplicitTargetVerification(script)

  if OPTIONS.verify and vendor_diff:
    script.Print("Remounting and verifying vendor partition files...")
    script.Unmount("/vendor")
    script.Mount("/vendor")
    vendor_diff.EmitExplicitTargetVerification(script)
  script.AddToZip(target_zip, output_zip, input_path=OPTIONS.updater_binary)

  WriteMetadata(metadata, output_zip)


def main(argv):

  def option_handler(o, a):
    if o == "--board_config":
      pass   # deprecated
    elif o in ("-k", "--package_key"):
      OPTIONS.package_key = a
    elif o in ("-i", "--incremental_from"):
      OPTIONS.incremental_source = a
    elif o in ("-w", "--wipe_user_data"):
      OPTIONS.wipe_user_data = True
    elif o in ("-n", "--no_prereq"):
      OPTIONS.omit_prereq = True
    elif o in ("-o", "--oem_settings"):
      OPTIONS.oem_source = a
    elif o in ("-e", "--extra_script"):
      OPTIONS.extra_script = a
    elif o in ("-a", "--aslr_mode"):
      if a in ("on", "On", "true", "True", "yes", "Yes"):
        OPTIONS.aslr_mode = True
      else:
        OPTIONS.aslr_mode = False
    elif o in ("-t", "--worker_threads"):
      if a.isdigit():
        OPTIONS.worker_threads = int(a)
      else:
        raise ValueError("Cannot parse value %r for option %r - only "
                         "integers are allowed." % (a, o))
    elif o in ("-2", "--two_step"):
      OPTIONS.two_step = True
    elif o == "--no_signing":
      OPTIONS.no_signing = True
    elif o in ("--verify"):
      OPTIONS.verify = True
    elif o == "--block":
      OPTIONS.block_based = True
    elif o in ("-b", "--binary"):
      OPTIONS.updater_binary = a
    elif o in ("--no_fallback_to_full",):
      OPTIONS.fallback_to_full = False
    else:
      return False
    return True

  args = common.ParseOptions(argv, __doc__,
                             extra_opts="b:k:i:d:wne:t:a:2o:",
                             extra_long_opts=["board_config=",
                                              "package_key=",
                                              "incremental_from=",
                                              "wipe_user_data",
                                              "no_prereq",
                                              "extra_script=",
                                              "worker_threads=",
                                              "aslr_mode=",
                                              "two_step",
                                              "no_signing",
                                              "block",
                                              "binary=",
                                              "oem_settings=",
                                              "verify",
                                              "no_fallback_to_full",
                                              ],
                             extra_option_handler=option_handler)

  if len(args) != 2:
    common.Usage(__doc__)
    sys.exit(1)

  if OPTIONS.extra_script is not None:
    OPTIONS.extra_script = open(OPTIONS.extra_script).read()

  print "unzipping target target-files..."
  OPTIONS.input_tmp, input_zip = common.UnzipTemp(args[0])

  OPTIONS.target_tmp = OPTIONS.input_tmp
  OPTIONS.info_dict = common.LoadInfoDict(input_zip)

  # If this image was originally labelled with SELinux contexts, make sure we
  # also apply the labels in our new image. During building, the "file_contexts"
  # is in the out/ directory tree, but for repacking from target-files.zip it's
  # in the root directory of the ramdisk.
  if "selinux_fc" in OPTIONS.info_dict:
    OPTIONS.info_dict["selinux_fc"] = os.path.join(OPTIONS.input_tmp, "BOOT", "RAMDISK",
        "file_contexts")

  if OPTIONS.verbose:
    print "--- target info ---"
    common.DumpInfoDict(OPTIONS.info_dict)

  # If the caller explicitly specified the device-specific extensions
  # path via -s/--device_specific, use that.  Otherwise, use
  # META/releasetools.py if it is present in the target target_files.
  # Otherwise, take the path of the file from 'tool_extensions' in the
  # info dict and look for that in the local filesystem, relative to
  # the current directory.

  if OPTIONS.device_specific is None:
    from_input = os.path.join(OPTIONS.input_tmp, "META", "releasetools.py")
    if os.path.exists(from_input):
      print "(using device-specific extensions from target_files)"
      OPTIONS.device_specific = from_input
    else:
      OPTIONS.device_specific = OPTIONS.info_dict.get("tool_extensions", None)

  if OPTIONS.device_specific is not None:
    OPTIONS.device_specific = os.path.abspath(OPTIONS.device_specific)

  while True:

    if OPTIONS.no_signing:
      if os.path.exists(args[1]): os.unlink(args[1])
      output_zip = zipfile.ZipFile(args[1], "w", compression=zipfile.ZIP_DEFLATED)
    else:
      temp_zip_file = tempfile.NamedTemporaryFile()
      output_zip = zipfile.ZipFile(temp_zip_file, "w",
                                   compression=zipfile.ZIP_DEFLATED)

    if OPTIONS.incremental_source is None:
      WriteFullOTAPackage(input_zip, output_zip)
      if OPTIONS.package_key is None:
        OPTIONS.package_key = OPTIONS.info_dict.get(
            "default_system_dev_certificate",
            "build/target/product/security/testkey")
      break

    else:
      print "unzipping source target-files..."
      OPTIONS.source_tmp, source_zip = common.UnzipTemp(OPTIONS.incremental_source)
      OPTIONS.target_info_dict = OPTIONS.info_dict
      OPTIONS.source_info_dict = common.LoadInfoDict(source_zip)
      if "selinux_fc" in OPTIONS.source_info_dict:
        OPTIONS.source_info_dict["selinux_fc"] = os.path.join(OPTIONS.source_tmp, "BOOT", "RAMDISK",
                                                              "file_contexts")
      if OPTIONS.package_key is None:
        OPTIONS.package_key = OPTIONS.source_info_dict.get(
            "default_system_dev_certificate",
            "build/target/product/security/testkey")
      if OPTIONS.verbose:
        print "--- source info ---"
        common.DumpInfoDict(OPTIONS.source_info_dict)
      try:
        WriteIncrementalOTAPackage(input_zip, source_zip, output_zip)
        break
      except ValueError:
        if not OPTIONS.fallback_to_full: raise
        print "--- failed to build incremental; falling back to full ---"
        OPTIONS.incremental_source = None
        output_zip.close()

  output_zip.close()

  if not OPTIONS.no_signing:
    SignOutput(temp_zip_file.name, args[1])
    temp_zip_file.close()

  print "done."


if __name__ == '__main__':
  try:
    common.CloseInheritedPipes()
    main(sys.argv[1:])
  except common.ExternalError, e:
    print
    print "   ERROR: %s" % (e,)
    print
    sys.exit(1)
  finally:
    common.Cleanup()