e709b094e4
When target defines 'BOARD_EXT4_SHARE_DUP_BLOCKS := true', the generated
system/vendor images may contain shared blocks (i.e. some blocks will
show up in multiple files' block list), which violates the current
assumptions in BBOTA script.
This CL allows generating BBOTAs by considering the first occurrence as
the "owner" of the shared blocks. All the later users of the shared
blocks will have an incomplete block list, whose RangeSet's will be
tagged with 'uses_shared_blocks'.
Files with 'uses_shared_blocks' tag will not be diff'd with imgdiff,
potentially with patch size penalty. Such files will be accounted for in
imgdiff stats report, where we can revisit for a better solution.
Bug: 64109868
Test: Generate BBOTA full and incremental package with targets defining
'BOARD_EXT4_SHARE_DUP_BLOCKS := true'.
Change-Id: I87fbc22eef7fafe2a470a03fdcfa1babf088ea8d
315 lines
11 KiB
Python
315 lines
11 KiB
Python
# Copyright (C) 2014 The Android Open Source Project
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import bisect
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import os
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import struct
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import threading
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from hashlib import sha1
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import rangelib
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class SparseImage(object):
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"""Wraps a sparse image file into an image object.
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Wraps a sparse image file (and optional file map and clobbered_blocks) into
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an image object suitable for passing to BlockImageDiff. file_map contains
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the mapping between files and their blocks. clobbered_blocks contains the set
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of blocks that should be always written to the target regardless of the old
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contents (i.e. copying instead of patching). clobbered_blocks should be in
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the form of a string like "0" or "0 1-5 8".
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"""
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def __init__(self, simg_fn, file_map_fn=None, clobbered_blocks=None,
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mode="rb", build_map=True, allow_shared_blocks=False):
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self.simg_f = f = open(simg_fn, mode)
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header_bin = f.read(28)
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header = struct.unpack("<I4H4I", header_bin)
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magic = header[0]
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major_version = header[1]
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minor_version = header[2]
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file_hdr_sz = header[3]
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chunk_hdr_sz = header[4]
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self.blocksize = blk_sz = header[5]
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self.total_blocks = total_blks = header[6]
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self.total_chunks = total_chunks = header[7]
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if magic != 0xED26FF3A:
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raise ValueError("Magic should be 0xED26FF3A but is 0x%08X" % (magic,))
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if major_version != 1 or minor_version != 0:
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raise ValueError("I know about version 1.0, but this is version %u.%u" %
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(major_version, minor_version))
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if file_hdr_sz != 28:
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raise ValueError("File header size was expected to be 28, but is %u." %
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(file_hdr_sz,))
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if chunk_hdr_sz != 12:
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raise ValueError("Chunk header size was expected to be 12, but is %u." %
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(chunk_hdr_sz,))
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print("Total of %u %u-byte output blocks in %u input chunks."
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% (total_blks, blk_sz, total_chunks))
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if not build_map:
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return
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pos = 0 # in blocks
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care_data = []
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self.offset_map = offset_map = []
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self.clobbered_blocks = rangelib.RangeSet(data=clobbered_blocks)
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for i in range(total_chunks):
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header_bin = f.read(12)
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header = struct.unpack("<2H2I", header_bin)
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chunk_type = header[0]
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chunk_sz = header[2]
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total_sz = header[3]
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data_sz = total_sz - 12
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if chunk_type == 0xCAC1:
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if data_sz != (chunk_sz * blk_sz):
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raise ValueError(
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"Raw chunk input size (%u) does not match output size (%u)" %
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(data_sz, chunk_sz * blk_sz))
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else:
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care_data.append(pos)
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care_data.append(pos + chunk_sz)
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offset_map.append((pos, chunk_sz, f.tell(), None))
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pos += chunk_sz
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f.seek(data_sz, os.SEEK_CUR)
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elif chunk_type == 0xCAC2:
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fill_data = f.read(4)
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care_data.append(pos)
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care_data.append(pos + chunk_sz)
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offset_map.append((pos, chunk_sz, None, fill_data))
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pos += chunk_sz
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elif chunk_type == 0xCAC3:
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if data_sz != 0:
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raise ValueError("Don't care chunk input size is non-zero (%u)" %
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(data_sz))
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else:
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pos += chunk_sz
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elif chunk_type == 0xCAC4:
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raise ValueError("CRC32 chunks are not supported")
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else:
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raise ValueError("Unknown chunk type 0x%04X not supported" %
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(chunk_type,))
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self.generator_lock = threading.Lock()
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self.care_map = rangelib.RangeSet(care_data)
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self.offset_index = [i[0] for i in offset_map]
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# Bug: 20881595
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# Introduce extended blocks as a workaround for the bug. dm-verity may
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# touch blocks that are not in the care_map due to block device
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# read-ahead. It will fail if such blocks contain non-zeroes. We zero out
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# the extended blocks explicitly to avoid dm-verity failures. 512 blocks
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# are the maximum read-ahead we configure for dm-verity block devices.
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extended = self.care_map.extend(512)
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all_blocks = rangelib.RangeSet(data=(0, self.total_blocks))
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extended = extended.intersect(all_blocks).subtract(self.care_map)
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self.extended = extended
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if file_map_fn:
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self.LoadFileBlockMap(file_map_fn, self.clobbered_blocks,
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allow_shared_blocks)
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else:
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self.file_map = {"__DATA": self.care_map}
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def AppendFillChunk(self, data, blocks):
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f = self.simg_f
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# Append a fill chunk
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f.seek(0, os.SEEK_END)
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f.write(struct.pack("<2H3I", 0xCAC2, 0, blocks, 16, data))
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# Update the sparse header
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self.total_blocks += blocks
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self.total_chunks += 1
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f.seek(16, os.SEEK_SET)
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f.write(struct.pack("<2I", self.total_blocks, self.total_chunks))
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def RangeSha1(self, ranges):
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h = sha1()
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for data in self._GetRangeData(ranges):
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h.update(data)
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return h.hexdigest()
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def ReadRangeSet(self, ranges):
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return [d for d in self._GetRangeData(ranges)]
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def TotalSha1(self, include_clobbered_blocks=False):
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"""Return the SHA-1 hash of all data in the 'care' regions.
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If include_clobbered_blocks is True, it returns the hash including the
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clobbered_blocks."""
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ranges = self.care_map
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if not include_clobbered_blocks:
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ranges = ranges.subtract(self.clobbered_blocks)
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return self.RangeSha1(ranges)
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def WriteRangeDataToFd(self, ranges, fd):
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for data in self._GetRangeData(ranges):
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fd.write(data)
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def _GetRangeData(self, ranges):
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"""Generator that produces all the image data in 'ranges'. The
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number of individual pieces returned is arbitrary (and in
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particular is not necessarily equal to the number of ranges in
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'ranges'.
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Use a lock to protect the generator so that we will not run two
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instances of this generator on the same object simultaneously."""
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f = self.simg_f
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with self.generator_lock:
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for s, e in ranges:
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to_read = e-s
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idx = bisect.bisect_right(self.offset_index, s) - 1
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chunk_start, chunk_len, filepos, fill_data = self.offset_map[idx]
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# for the first chunk we may be starting partway through it.
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remain = chunk_len - (s - chunk_start)
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this_read = min(remain, to_read)
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if filepos is not None:
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p = filepos + ((s - chunk_start) * self.blocksize)
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f.seek(p, os.SEEK_SET)
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yield f.read(this_read * self.blocksize)
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else:
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yield fill_data * (this_read * (self.blocksize >> 2))
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to_read -= this_read
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while to_read > 0:
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# continue with following chunks if this range spans multiple chunks.
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idx += 1
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chunk_start, chunk_len, filepos, fill_data = self.offset_map[idx]
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this_read = min(chunk_len, to_read)
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if filepos is not None:
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f.seek(filepos, os.SEEK_SET)
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yield f.read(this_read * self.blocksize)
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else:
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yield fill_data * (this_read * (self.blocksize >> 2))
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to_read -= this_read
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def LoadFileBlockMap(self, fn, clobbered_blocks, allow_shared_blocks):
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"""Loads the given block map file.
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Args:
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fn: The filename of the block map file.
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clobbered_blocks: A RangeSet instance for the clobbered blocks.
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allow_shared_blocks: Whether having shared blocks is allowed.
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"""
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remaining = self.care_map
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self.file_map = out = {}
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with open(fn) as f:
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for line in f:
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fn, ranges = line.split(None, 1)
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ranges = rangelib.RangeSet.parse(ranges)
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if allow_shared_blocks:
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# Find the shared blocks that have been claimed by others.
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shared_blocks = ranges.subtract(remaining)
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if shared_blocks:
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ranges = ranges.subtract(shared_blocks)
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if not ranges:
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continue
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# Tag the entry so that we can skip applying imgdiff on this file.
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ranges.extra['uses_shared_blocks'] = True
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out[fn] = ranges
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assert ranges.size() == ranges.intersect(remaining).size()
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# Currently we assume that blocks in clobbered_blocks are not part of
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# any file.
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assert not clobbered_blocks.overlaps(ranges)
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remaining = remaining.subtract(ranges)
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remaining = remaining.subtract(clobbered_blocks)
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# For all the remaining blocks in the care_map (ie, those that
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# aren't part of the data for any file nor part of the clobbered_blocks),
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# divide them into blocks that are all zero and blocks that aren't.
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# (Zero blocks are handled specially because (1) there are usually
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# a lot of them and (2) bsdiff handles files with long sequences of
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# repeated bytes especially poorly.)
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zero_blocks = []
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nonzero_blocks = []
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reference = '\0' * self.blocksize
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# Workaround for bug 23227672. For squashfs, we don't have a system.map. So
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# the whole system image will be treated as a single file. But for some
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# unknown bug, the updater will be killed due to OOM when writing back the
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# patched image to flash (observed on lenok-userdebug MEA49). Prior to
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# getting a real fix, we evenly divide the non-zero blocks into smaller
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# groups (currently 1024 blocks or 4MB per group).
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# Bug: 23227672
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MAX_BLOCKS_PER_GROUP = 1024
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nonzero_groups = []
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f = self.simg_f
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for s, e in remaining:
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for b in range(s, e):
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idx = bisect.bisect_right(self.offset_index, b) - 1
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chunk_start, _, filepos, fill_data = self.offset_map[idx]
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if filepos is not None:
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filepos += (b-chunk_start) * self.blocksize
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f.seek(filepos, os.SEEK_SET)
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data = f.read(self.blocksize)
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else:
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if fill_data == reference[:4]: # fill with all zeros
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data = reference
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else:
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data = None
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if data == reference:
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zero_blocks.append(b)
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zero_blocks.append(b+1)
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else:
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nonzero_blocks.append(b)
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nonzero_blocks.append(b+1)
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if len(nonzero_blocks) >= MAX_BLOCKS_PER_GROUP:
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nonzero_groups.append(nonzero_blocks)
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# Clear the list.
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nonzero_blocks = []
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if nonzero_blocks:
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nonzero_groups.append(nonzero_blocks)
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nonzero_blocks = []
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assert zero_blocks or nonzero_groups or clobbered_blocks
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if zero_blocks:
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out["__ZERO"] = rangelib.RangeSet(data=zero_blocks)
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if nonzero_groups:
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for i, blocks in enumerate(nonzero_groups):
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out["__NONZERO-%d" % i] = rangelib.RangeSet(data=blocks)
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if clobbered_blocks:
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out["__COPY"] = clobbered_blocks
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def ResetFileMap(self):
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"""Throw away the file map and treat the entire image as
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undifferentiated data."""
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self.file_map = {"__DATA": self.care_map}
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