1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
|
/*
* 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;
}
}
|
