| /* |
| * Copyright (C) 2019 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. |
| */ |
| |
| package com.android.dynsystem; |
| |
| import static java.lang.Math.min; |
| |
| import java.io.BufferedInputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.nio.ByteBuffer; |
| import java.nio.ByteOrder; |
| import java.util.Arrays; |
| |
| /** |
| * SparseInputStream read from upstream and detects the data format. If the upstream is a valid |
| * sparse data, it will unsparse it on the fly. Otherwise, it just passthrough as is. |
| */ |
| public class SparseInputStream extends InputStream { |
| static final int FILE_HDR_SIZE = 28; |
| static final int CHUNK_HDR_SIZE = 12; |
| |
| /** |
| * This class represents a chunk in the Android sparse image. |
| * |
| * @see system/core/libsparse/sparse_format.h |
| */ |
| private class SparseChunk { |
| static final short RAW = (short) 0xCAC1; |
| static final short FILL = (short) 0xCAC2; |
| static final short DONTCARE = (short) 0xCAC3; |
| public short mChunkType; |
| public int mChunkSize; |
| public int mTotalSize; |
| public byte[] fill; |
| public String toString() { |
| return String.format( |
| "type: %x, chunk_size: %d, total_size: %d", mChunkType, mChunkSize, mTotalSize); |
| } |
| } |
| |
| private byte[] readFull(InputStream in, int size) throws IOException { |
| byte[] buf = new byte[size]; |
| for (int done = 0, n = 0; done < size; done += n) { |
| if ((n = in.read(buf, done, size - done)) < 0) { |
| throw new IOException("Failed to readFull"); |
| } |
| } |
| return buf; |
| } |
| |
| private ByteBuffer readBuffer(InputStream in, int size) throws IOException { |
| return ByteBuffer.wrap(readFull(in, size)).order(ByteOrder.LITTLE_ENDIAN); |
| } |
| |
| private SparseChunk readChunk(InputStream in) throws IOException { |
| SparseChunk chunk = new SparseChunk(); |
| ByteBuffer buf = readBuffer(in, CHUNK_HDR_SIZE); |
| chunk.mChunkType = buf.getShort(); |
| buf.getShort(); |
| chunk.mChunkSize = buf.getInt(); |
| chunk.mTotalSize = buf.getInt(); |
| return chunk; |
| } |
| |
| private BufferedInputStream mIn; |
| private boolean mIsSparse; |
| private long mBlockSize; |
| private long mTotalBlocks; |
| private long mTotalChunks; |
| private SparseChunk mCur; |
| private long mLeft; |
| private int mCurChunks; |
| |
| public SparseInputStream(BufferedInputStream in) throws IOException { |
| mIn = in; |
| in.mark(FILE_HDR_SIZE * 2); |
| ByteBuffer buf = readBuffer(mIn, FILE_HDR_SIZE); |
| mIsSparse = (buf.getInt() == 0xed26ff3a); |
| if (!mIsSparse) { |
| mIn.reset(); |
| return; |
| } |
| int major = buf.getShort(); |
| int minor = buf.getShort(); |
| |
| if (major > 0x1 || minor > 0x0) { |
| throw new IOException("Unsupported sparse version: " + major + "." + minor); |
| } |
| |
| if (buf.getShort() != FILE_HDR_SIZE) { |
| throw new IOException("Illegal file header size"); |
| } |
| if (buf.getShort() != CHUNK_HDR_SIZE) { |
| throw new IOException("Illegal chunk header size"); |
| } |
| mBlockSize = buf.getInt(); |
| if ((mBlockSize & 0x3) != 0) { |
| throw new IOException("Illegal block size, must be a multiple of 4"); |
| } |
| mTotalBlocks = buf.getInt(); |
| mTotalChunks = buf.getInt(); |
| mLeft = mCurChunks = 0; |
| } |
| |
| /** |
| * Check if it needs to open a new chunk. |
| * |
| * @return true if it's EOF |
| */ |
| private boolean prepareChunk() throws IOException { |
| if (mCur == null || mLeft <= 0) { |
| if (++mCurChunks > mTotalChunks) return true; |
| mCur = readChunk(mIn); |
| if (mCur.mChunkType == SparseChunk.FILL) { |
| mCur.fill = readFull(mIn, 4); |
| } |
| mLeft = mCur.mChunkSize * mBlockSize; |
| } |
| return mLeft == 0; |
| } |
| |
| /** |
| * It overrides the InputStream.read(byte[] buf) |
| */ |
| public int read(byte[] buf) throws IOException { |
| if (!mIsSparse) { |
| return mIn.read(buf); |
| } |
| if (prepareChunk()) return -1; |
| int n = -1; |
| switch (mCur.mChunkType) { |
| case SparseChunk.RAW: |
| n = mIn.read(buf, 0, (int) min(mLeft, buf.length)); |
| mLeft -= n; |
| return n; |
| case SparseChunk.DONTCARE: |
| n = (int) min(mLeft, buf.length); |
| Arrays.fill(buf, 0, n - 1, (byte) 0); |
| mLeft -= n; |
| return n; |
| case SparseChunk.FILL: |
| // The FILL type is rarely used, so use a simple implmentation. |
| return super.read(buf); |
| default: |
| throw new IOException("Unsupported Chunk:" + mCur.toString()); |
| } |
| } |
| |
| /** |
| * It overrides the InputStream.read() |
| */ |
| public int read() throws IOException { |
| if (!mIsSparse) { |
| return mIn.read(); |
| } |
| if (prepareChunk()) return -1; |
| int ret = -1; |
| switch (mCur.mChunkType) { |
| case SparseChunk.RAW: |
| ret = mIn.read(); |
| break; |
| case SparseChunk.DONTCARE: |
| ret = 0; |
| break; |
| case SparseChunk.FILL: |
| ret = mCur.fill[(4 - ((int) mLeft & 0x3)) & 0x3]; |
| break; |
| default: |
| throw new IOException("Unsupported Chunk:" + mCur.toString()); |
| } |
| mLeft--; |
| return ret; |
| } |
| |
| /** |
| * Get the unsparse size |
| * @return -1 if unknown |
| */ |
| public long getUnsparseSize() { |
| if (!mIsSparse) { |
| return -1; |
| } |
| return mBlockSize * mTotalBlocks; |
| } |
| } |