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Commit 405e71dc authored by Sami Tolvanen's avatar Sami Tolvanen
Browse files

Fix metadata location when file system doesn't span the partition 

Pad the sparse image with a zero fill chunk to correctly position
verity and FEC metadata at the end of the partition.

Bug: 27073791
Change-Id: I9f70d579a42e5007d50e9c02a98a608d2815f0ed
(cherry picked from commit 6a8781a2)
parent fb5ac541

tools/releasetools/build_image.py

+14 −7
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ import sys 
import commands

import common

import shutil

import sparse_img

import tempfile



OPTIONS = common.OPTIONS
@@ -91,6 +92,16 @@ def GetVeritySize(partition_size, fec_supported): 
    return verity_size + fec_size

  return verity_size



def GetSimgSize(image_file):

  simg = sparse_img.SparseImage(image_file, build_map=False)

  return simg.blocksize * simg.total_blocks



def ZeroPadSimg(image_file, pad_size):

  blocks = pad_size // BLOCK_SIZE

  print("Padding %d blocks (%d bytes)" % (blocks, pad_size))

  simg = sparse_img.SparseImage(image_file, mode="r+b", build_map=False)

  simg.AppendFillChunk(0, blocks)



def AdjustPartitionSizeForVerity(partition_size, fec_supported):

  """Modifies the provided partition size to account for the verity metadata.
@@ -329,7 +340,7 @@ def BuildImage(in_dir, prop_dict, out_file, target_out=None): 


  # Adjust the partition size to make room for the hashes if this is to be

  # verified.

  if verity_supported and is_verity_partition and fs_spans_partition:

  if verity_supported and is_verity_partition:

    partition_size = int(prop_dict.get("partition_size"))

    adjusted_size = AdjustPartitionSizeForVerity(partition_size,

                                                 verity_fec_supported)
@@ -440,17 +451,13 @@ def BuildImage(in_dir, prop_dict, out_file, target_out=None): 
  if not fs_spans_partition:

    mount_point = prop_dict.get("mount_point")

    partition_size = int(prop_dict.get("partition_size"))

    image_size = os.stat(out_file).st_size

    image_size = GetSimgSize(out_file)

    if image_size > partition_size:

      print("Error: %s image size of %d is larger than partition size of "

            "%d" % (mount_point, image_size, partition_size))

      return False

    if verity_supported and is_verity_partition:

      if 2 * image_size - AdjustPartitionSizeForVerity(image_size, verity_fec_supported) > partition_size:

        print "Error: No more room on %s to fit verity data" % mount_point

        return False

    prop_dict["original_partition_size"] = prop_dict["partition_size"]

    prop_dict["partition_size"] = str(image_size)

      ZeroPadSimg(out_file, partition_size - image_size)



  # create the verified image if this is to be verified

  if verity_supported and is_verity_partition:

tools/releasetools/sparse_img.py

+21 −3
Original line number Diff line number Diff line
@@ -31,8 +31,9 @@ class SparseImage(object): 
  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")

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

               mode="rb", build_map=True):

    self.simg_f = f = open(simg_fn, mode)



    header_bin = f.read(28)

    header = struct.unpack("<I4H4I", header_bin)
@@ -44,7 +45,7 @@ class SparseImage(object): 
    chunk_hdr_sz = header[4]

    self.blocksize = blk_sz = header[5]

    self.total_blocks = total_blks = header[6]

    total_chunks = header[7]

    self.total_chunks = total_chunks = header[7]



    if magic != 0xED26FF3A:

      raise ValueError("Magic should be 0xED26FF3A but is 0x%08X" % (magic,))
@@ -61,6 +62,9 @@ class SparseImage(object): 
    print("Total of %u %u-byte output blocks in %u input chunks."

          % (total_blks, blk_sz, total_chunks))



    if not build_map:

      return



    pos = 0   # in blocks

    care_data = []

    self.offset_map = offset_map = []
@@ -126,6 +130,20 @@ class SparseImage(object): 
    else:

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



  def AppendFillChunk(self, data, blocks):

    f = self.simg_f



    # Append a fill chunk

    f.seek(0, os.SEEK_END)

    f.write(struct.pack("<2H3I", 0xCAC2, 0, blocks, 16, data))



    # Update the sparse header

    self.total_blocks += blocks

    self.total_chunks += 1



    f.seek(16, os.SEEK_SET)

    f.write(struct.pack("<2I", self.total_blocks, self.total_chunks))



  def ReadRangeSet(self, ranges):

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