#!/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.

  -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.

"""

import sys

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

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

try:
  from hashlib import sha1 as sha1
except ImportError:
  from sha import sha as sha1

import common
import img_from_target_files
import edify_generator
import build_image

OPTIONS = common.OPTIONS
OPTIONS.package_key = None
OPTIONS.incremental_source = None
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 = 3
OPTIONS.two_step = False
OPTIONS.no_signing = False
OPTIONS.block_based = False
OPTIONS.updater_binary = None
OPTIONS.oem_source = None

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 Item:
  """Items represent the metadata (user, group, mode) of files and
  directories in the system image."""
  ITEMS = {}
  def __init__(self, name, dir=False):
    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 = Item.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)

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

  @classmethod
  def GetMetadata(cls, input_zip):

    # The target_files contains a record of what the uid,
    # gid, and mode are supposed to be.
    output = input_zip.read("META/filesystem_config.txt")

    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 = cls.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 = cls.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 = cls.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

  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 CopySystemFiles(input_zip, output_zip=None,
                    substitute=None):
  """Copies files underneath system/ 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 = []

  for info in input_zip.infolist():
    if info.filename.startswith("SYSTEM/"):
      basefilename = info.filename[7:]
      if IsSymlink(info):
        symlinks.append((input_zip.read(info.filename),
                         "/system/" + basefilename))
      else:
        info2 = copy.copy(info)
        fn = info2.filename = "system/" + 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("/"):
          Item.Get(fn[:-1], dir=True)
        else:
          Item.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:
    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 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 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")
  oem_dict = None
  if oem_props is not None:
    if OPTIONS.oem_source is None:
      raise common.ExternalError("OEM source required for this build")
    script.Mount("/oem")
    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", "stage") == "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", "stage") == "3/3" then
""" % bcb_dev)

  device_specific.FullOTA_InstallBegin()

  system_progress = 0.75

  if OPTIONS.wipe_user_data:
    system_progress -= 0.1

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

  script.ShowProgress(system_progress, 30)
  if block_based:
    mapdata, data = img_from_target_files.BuildSystem(
        OPTIONS.input_tmp, OPTIONS.info_dict,
        sparse=False, map_file=True)

    common.ZipWriteStr(output_zip, "system.map", mapdata)
    common.ZipWriteStr(output_zip, "system.muimg", data)
    script.WipeBlockDevice("/system")
    script.WriteRawImage("/system", "system.muimg", mapfn="system.map")
  else:
    script.FormatPartition("/system")
    script.Mount("/system")
    if not has_recovery_patch:
      script.UnpackPackageDir("recovery", "/system")
    script.UnpackPackageDir("system", "/system")

    symlinks = CopySystemFiles(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)
      Item.Get("system/" + fn, dir=False)

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

    Item.GetMetadata(input_zip)
    Item.Get("system").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_context, output_zip):
  f = open(file_context, 'r');
  basename = os.path.basename(file_context)
  common.ZipWriteStr(output_zip, basename, f.read())


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 LoadSystemFiles(z):
  """Load all the files from SYSTEM/... in a given target-files
  ZipFile, and return a dict of {filename: File object}."""
  out = {}
  for info in z.infolist():
    if info.filename.startswith("SYSTEM/") and not IsSymlink(info):
      basefilename = info.filename[7:]
      fn = "system/" + 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)

  with tempfile.NamedTemporaryFile() as src_file:
    with tempfile.NamedTemporaryFile() as tgt_file:
      print "building source system image..."
      src_file = tempfile.NamedTemporaryFile()
      src_mapdata, src_data = img_from_target_files.BuildSystem(
          OPTIONS.source_tmp, OPTIONS.source_info_dict,
          sparse=False, map_file=True)

      src_sys_sha1 = sha1(src_data).hexdigest()
      print "source system sha1:", src_sys_sha1
      src_file.write(src_data)

      print "building target system image..."
      tgt_file = tempfile.NamedTemporaryFile()
      tgt_mapdata, tgt_data = img_from_target_files.BuildSystem(
          OPTIONS.target_tmp, OPTIONS.target_info_dict,
          sparse=False, map_file=True)
      tgt_sys_sha1 = sha1(tgt_data).hexdigest()
      print "target system sha1:", tgt_sys_sha1
      tgt_sys_len = len(tgt_data)
      tgt_file.write(tgt_data)

      system_type, system_device = common.GetTypeAndDevice("/system", OPTIONS.info_dict)
      system_patch = common.MakeSystemPatch(src_file, tgt_file)

      TestBlockPatch(src_data, src_mapdata, system_patch.data, tgt_mapdata, tgt_sys_sha1)
      src_data = None
      tgt_data = None

      system_patch.AddToZip(output_zip, compression=zipfile.ZIP_STORED)
      src_mapfilename = system_patch.name + ".src.map"
      common.ZipWriteStr(output_zip, src_mapfilename, src_mapdata)
      tgt_mapfilename = system_patch.name + ".tgt.map"
      common.ZipWriteStr(output_zip, tgt_mapfilename, tgt_mapdata)

  oem_props = OPTIONS.target_info_dict.get("oem_fingerprint_properties")
  oem_dict = None
  if oem_props is not None:
    if OPTIONS.oem_source is None:
      raise common.ExternalError("OEM source required for this build")
    script.Mount("/oem")
    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", "stage") == "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", "stage") != "3/3" then
""" % bcb_dev)

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

  device_specific.IncrementalOTA_VerifyBegin()

  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))

  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))

  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()

  script.Print("Patching system image...")
  script.Syspatch(system_device,
                  tgt_mapfilename, tgt_sys_sha1,
                  src_mapfilename, src_sys_sha1,
                  system_patch.name)

  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:
      # 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")
      print "boot image changed; including."
    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)

def ParseMap(map_str):
  x = map_str.split()
  assert int(x[0]) == 4096
  assert int(x[1]) == len(x)-2
  return int(x[0]), [int(i) for i in x[2:]]

def TestBlockPatch(src_muimg, src_map, patch_data, tgt_map, tgt_sha1):
  src_blksize, src_regions = ParseMap(src_map)
  tgt_blksize, tgt_regions = ParseMap(tgt_map)

  with tempfile.NamedTemporaryFile() as src_file,\
       tempfile.NamedTemporaryFile() as patch_file,\
       tempfile.NamedTemporaryFile() as tgt_file,\
       tempfile.NamedTemporaryFile() as src_map_file,\
       tempfile.NamedTemporaryFile() as tgt_map_file:

    src_total = sum(src_regions) * src_blksize
    src_file.truncate(src_total)
    p = 0
    for i in range(0, len(src_regions), 2):
      c, dc = src_regions[i:i+2]
      src_file.write(src_muimg[p:(p+c*src_blksize)])
      p += c*src_blksize
      src_file.seek(dc*src_blksize, 1)
    assert src_file.tell() == src_total

    patch_file.write(patch_data)

    tgt_total = sum(tgt_regions) * tgt_blksize
    tgt_file.truncate(tgt_total)

    src_map_file.write(src_map)
    tgt_map_file.write(tgt_map)

    src_file.flush()
    src_map_file.flush()
    patch_file.flush()
    tgt_file.flush()
    tgt_map_file.flush()

    p = common.Run(["syspatch_host", src_file.name, src_map_file.name,
                    patch_file.name, tgt_file.name, tgt_map_file.name],
                   stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
    stdoutdata, _ = p.communicate()
    if p.returncode != 0:
      print stdoutdata
      raise ValueError("failed to reconstruct target system image from patch")

    h = sha1()
    for i in range(0, len(tgt_regions), 2):
      c, dc = tgt_regions[i:i+2]
      h.update(tgt_file.read(c*tgt_blksize))
      tgt_file.seek(dc*tgt_blksize, 1)

    if h.hexdigest() != tgt_sha1:
      raise ValueError("patch reconstructed incorrect target system image")

  print "test of system image patch succeeded"


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")
  oem_dict = None
  if oem_props is not None:
    if OPTIONS.oem_source is None:
      raise common.ExternalError("OEM source required for this build")
    script.Mount("/oem")
    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)

  print "Loading target..."
  target_data = LoadSystemFiles(target_zip)
  print "Loading source..."
  source_data = LoadSystemFiles(source_zip)

  verbatim_targets = []
  patch_list = []
  diffs = []
  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))
      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))
      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)

  script.Mount("/system")

  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", "stage") == "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", "stage") != "3/3" then
""" % bcb_dev)

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

  device_specific.IncrementalOTA_VerifyBegin()

  script.ShowProgress(0.1, 0)
  so_far = 0

  for tf, sf, size, patch_sha in 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

  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

  if patch_list or updating_recovery or updating_boot:
    script.CacheFreeSpaceCheck(largest_source_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...")
  script.DeleteFiles(["/"+i[0] for i in verbatim_targets] +
                     ["/"+i for i in sorted(source_data)
                            if i not in target_data and
                            i not in renames] +
                     ["/system/recovery.img"])

  script.ShowProgress(0.8, 0)
  total_patch_size = float(sum([i[1].size for i in patch_list]) + 1)
  if updating_boot:
    total_patch_size += target_boot.size
  so_far = 0

  script.Print("Patching system files...")
  deferred_patch_list = []
  for item in 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)

  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."

  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)
        Item.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 = CopySystemFiles(target_zip, None)

  target_symlinks_d = dict([(i[1], i[0]) for i in target_symlinks])
  temp_script = script.MakeTemporary()
  Item.GetMetadata(target_zip)
  Item.Get("system").SetPermissions(temp_script)

  # Note that this call will mess up the tree of Items, so make sure
  # we're done with it.
  source_symlinks = CopySystemFiles(source_zip, None)
  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 verbatim_targets:
    script.Print("Unpacking new files...")
    script.UnpackPackageDir("system", "/system")

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

  if len(renames) > 0:
    script.Print("Renaming files...")

  for src in renames:
    print "Renaming " + src + " to " + renames[src].name
    script.RenameFile(src, renames[src].name)

  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...")
  for item in 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)

  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.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 ("--worker_threads"):
      OPTIONS.worker_threads = int(a)
    elif o in ("-2", "--two_step"):
      OPTIONS.two_step = True
    elif o == "--no_signing":
      OPTIONS.no_signing = True
    elif o == "--block":
      OPTIONS.block_based = True
    elif o in ("-b", "--binary"):
      OPTIONS.updater_binary = a
    else:
      return False
    return True

  args = common.ParseOptions(argv, __doc__,
                             extra_opts="b:k:i:d:wne: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=",
                                              ],
                             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)

  if OPTIONS.no_signing:
    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")
  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)
    WriteIncrementalOTAPackage(input_zip, source_zip, output_zip)

  output_zip.close()

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

  common.Cleanup()

  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)