Add support for clobbered blocks

  """A zero-length image."""

  blocksize = 4096

  care_map = RangeSet()

  clobbered_blocks = RangeSet()

  total_blocks = 0

  file_map = {}

  def ReadRangeSet(self, ranges):

    self.total_blocks = len(self.data) / self.blocksize

    self.care_map = RangeSet(data=(0, self.total_blocks))

    self.clobbered_blocks = RangeSet()

    zero_blocks = []

    nonzero_blocks = []

    return [self.data[s*self.blocksize:e*self.blocksize] for (s, e) in ranges]

  def TotalSha1(self):

    # DataImage always carries empty clobbered_blocks.

    assert self.clobbered_blocks.size() == 0

    return sha1(self.data).hexdigest()

#      (Typically a domain is a file, and the key in file_map is the

#      pathname.)

#

#    clobbered_blocks: a RangeSet containing which blocks contain data

#      but may be altered by the FS. They need to be excluded when

#      verifying the partition integrity.

#

#    ReadRangeSet(): a function that takes a RangeSet and returns the

#      data contained in the image blocks of that RangeSet.  The data

#      is returned as a list or tuple of strings; concatenating the

#

#    TotalSha1(): a function that returns (as a hex string) the SHA-1

#      hash of all the data in the image (ie, all the blocks in the

#      care_map)

#      care_map minus clobbered_blocks).

#

# When creating a BlockImageDiff, the src image may be None, in which

# case the list of transfers produced will never read from the

      if free_string:

        out.append("".join(free_string))

      # sanity check: abort if we're going to need more than 512 MB if

      # stash space

      assert max_stashed_blocks * self.tgt.blocksize < (512 << 20)

                 "zero", self.transfers)

        continue

      elif tgt_fn == "__COPY":

        # "__COPY" domain includes all the blocks not contained in any

        # file and that need to be copied unconditionally to the target.

        Transfer(tgt_fn, None, tgt_ranges, empty, "new", self.transfers)

        continue

      elif tgt_fn in self.src.file_map:

        # Look for an exact pathname match in the source.

        Transfer(tgt_fn, tgt_fn, tgt_ranges, self.src.file_map[tgt_fn],

    self.partition = partition

    self.check_first_block = check_first_block

    # Due to http://b/20939131, check_first_block is disabled temporarily.

    assert not self.check_first_block

    if version is None:

      version = 1

      if OPTIONS.info_dict:

    if not self.src:

      script.Print("Image %s will be patched unconditionally." % (partition,))

    else:

      ranges = self.src.care_map.subtract(self.src.clobbered_blocks)

      ranges_str = ranges.to_string_raw()

      if self.version >= 3:

        script.AppendExtra(('if (range_sha1("%s", "%s") == "%s" || '

                            'block_image_verify("%s", '

                            'package_extract_file("%s.transfer.list"), '

                            '"%s.new.dat", "%s.patch.dat")) then') % (

                            self.device, self.src.care_map.to_string_raw(),

                            self.src.TotalSha1(),

                            self.device, ranges_str, self.src.TotalSha1(),

                            self.device, partition, partition, partition))

      else:

        script.AppendExtra('if range_sha1("%s", "%s") == "%s" then' % (

            self.device, self.src.care_map.to_string_raw(),

            self.src.TotalSha1()))

                           self.device, ranges_str, self.src.TotalSha1()))

      script.Print('Verified %s image...' % (partition,))

      script.AppendExtra('else')

    return ctx.hexdigest()

  # TODO(tbao): Due to http://b/20939131, block 0 may be changed without

  # remounting R/W. Will change the checking to a finer-grained way to

  # mask off those bits.

  def _CheckFirstBlock(self, script):

    r = rangelib.RangeSet((0, 1))

    srchash = self._HashBlocks(self.src, r)

      path = add_img_to_target_files.BuildVendor(

          tmpdir, info_dict, block_list=mappath)

  return sparse_img.SparseImage(path, mappath)

  # Bug: http://b/20939131

  # In ext4 filesystems, block 0 might be changed even being mounted

  # R/O. We add it to clobbered_blocks so that it will be written to the

  # target unconditionally. Note that they are still part of care_map.

  clobbered_blocks = "0"

  return sparse_img.SparseImage(path, mappath, clobbered_blocks)

def WriteFullOTAPackage(input_zip, output_zip):

        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):

    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

class SparseImage(object):

  """Wraps a sparse image file (and optional file map) into an image

  object suitable for passing to BlockImageDiff."""

  """Wraps a sparse image file into an image object.

  def __init__(self, simg_fn, file_map_fn=None):

  Wraps a sparse image file (and optional file map and clobbered_blocks) into

  an image object suitable for passing to BlockImageDiff. file_map contains

  the mapping between files and their blocks. clobbered_blocks contains the set

  of blocks that should be always written to the target regardless of the old

  contents (i.e. copying instead of patching). clobbered_blocks should be in

  the form of a string like "0" or "0 1-5 8".

  """

  def __init__(self, simg_fn, file_map_fn=None, clobbered_blocks=None):

    self.simg_f = f = open(simg_fn, "rb")

    header_bin = f.read(28)

    pos = 0   # in blocks

    care_data = []

    self.offset_map = offset_map = []

    self.clobbered_blocks = rangelib.RangeSet(data=clobbered_blocks)

    for i in range(total_chunks):

      header_bin = f.read(12)

    self.offset_index = [i[0] for i in offset_map]

    if file_map_fn:

      self.LoadFileBlockMap(file_map_fn)

      self.LoadFileBlockMap(file_map_fn, self.clobbered_blocks)

    else:

      self.file_map = {"__DATA": self.care_map}

    return [d for d in self._GetRangeData(ranges)]

  def TotalSha1(self):

    """Return the SHA-1 hash of all data in the 'care' regions of this image."""

    """Return the SHA-1 hash of all data in the 'care' regions but not in

    clobbered_blocks of this image."""

    h = sha1()

    for d in self._GetRangeData(self.care_map):

    for d in self._GetRangeData(self.care_map.subtract(self.clobbered_blocks)):

      h.update(d)

    return h.hexdigest()

          yield fill_data * (this_read * (self.blocksize >> 2))

        to_read -= this_read

  def LoadFileBlockMap(self, fn):

  def LoadFileBlockMap(self, fn, clobbered_blocks):

    remaining = self.care_map

    self.file_map = out = {}

        ranges = rangelib.RangeSet.parse(ranges)

        out[fn] = ranges

        assert ranges.size() == ranges.intersect(remaining).size()

        # Currently we assume that blocks in clobbered_blocks are not part of

        # any file.

        assert not clobbered_blocks.overlaps(ranges)

        remaining = remaining.subtract(ranges)

    remaining = remaining.subtract(clobbered_blocks)

    # For all the remaining blocks in the care_map (ie, those that

    # aren't part of the data for any file), divide them into blocks

    # that are all zero and blocks that aren't.  (Zero blocks are

    # handled specially because (1) there are usually a lot of them

    # and (2) bsdiff handles files with long sequences of repeated

    # bytes especially poorly.)

    # aren't part of the data for any file nor part of the clobbered_blocks),

    # divide them into blocks that are all zero and blocks that aren't.

    # (Zero blocks are handled specially because (1) there are usually

    # a lot of them and (2) bsdiff handles files with long sequences of

    # repeated bytes especially poorly.)

    zero_blocks = []

    nonzero_blocks = []

    out["__ZERO"] = rangelib.RangeSet(data=zero_blocks)

    out["__NONZERO"] = rangelib.RangeSet(data=nonzero_blocks)

    out["__COPY"] = clobbered_blocks

  def ResetFileMap(self):

    """Throw away the file map and treat the entire image as