1 //
2 // Copyright (C) 2021 The Android Open Source Project
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 // http://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15 //
16
17 #include "lz4diff_compress.h"
18
19 #include "update_engine/common/utils.h"
20 #include "update_engine/common/hash_calculator.h"
21 #include "update_engine/payload_generator/delta_diff_generator.h"
22 #include "update_engine/payload_generator/payload_generation_config.h"
23
24 #include <base/logging.h>
25 #include <lz4.h>
26 #include <lz4hc.h>
27
28 namespace chromeos_update_engine {
29
TryCompressBlob(std::string_view blob,const std::vector<CompressedBlock> & block_info,const bool zero_padding_enabled,const CompressionAlgorithm compression_algo,const SinkFunc & sink)30 bool TryCompressBlob(std::string_view blob,
31 const std::vector<CompressedBlock>& block_info,
32 const bool zero_padding_enabled,
33 const CompressionAlgorithm compression_algo,
34 const SinkFunc& sink) {
35 size_t uncompressed_size = 0;
36 for (const auto& block : block_info) {
37 CHECK_EQ(uncompressed_size, block.uncompressed_offset)
38 << "Compressed block info is expected to be sorted.";
39 uncompressed_size += block.uncompressed_length;
40 }
41 auto hc = LZ4_createStreamHC();
42 DEFER {
43 if (hc) {
44 LZ4_freeStreamHC(hc);
45 hc = nullptr;
46 }
47 };
48 size_t compressed_offset = 0;
49 Blob block_buffer;
50 for (const auto& block : block_info) {
51 const auto uncompressed_block =
52 blob.substr(block.uncompressed_offset, block.uncompressed_length);
53 if (!block.IsCompressed()) {
54 TEST_EQ(sink(reinterpret_cast<const uint8_t*>(uncompressed_block.data()),
55 uncompressed_block.size()),
56 uncompressed_block.size());
57 continue;
58 }
59 block_buffer.resize(block.compressed_length);
60 // Execute the increment at end of each loop
61 DEFER {
62 compressed_offset += block.compressed_length;
63 block_buffer.clear();
64 };
65
66 int ret = 0;
67 // LZ4 spec enforces that last op of a compressed block must be an insert op
68 // of at least 5 bytes. Compressors will try to conform to that requirement
69 // if the input size is just right. We don't want that. So always give a
70 // little bit more data.
71 switch (int src_size = uncompressed_size - block.uncompressed_offset;
72 compression_algo.type()) {
73 case CompressionAlgorithm::LZ4HC:
74 ret = LZ4_compress_HC_destSize(
75 hc,
76 uncompressed_block.data(),
77 reinterpret_cast<char*>(block_buffer.data()),
78 &src_size,
79 block.compressed_length,
80 compression_algo.level());
81 break;
82 case CompressionAlgorithm::LZ4:
83 ret =
84 LZ4_compress_destSize(uncompressed_block.data(),
85 reinterpret_cast<char*>(block_buffer.data()),
86 &src_size,
87 block.compressed_length);
88 break;
89 default:
90 LOG(ERROR) << "Unrecognized compression algorithm: "
91 << compression_algo.type();
92 return {};
93 }
94 TEST_GT(ret, 0);
95 const uint64_t bytes_written = ret;
96 // Last block may have trailing zeros
97 TEST_LE(bytes_written, block.compressed_length);
98 if (bytes_written < block.compressed_length) {
99 if (zero_padding_enabled) {
100 const auto padding = block.compressed_length - bytes_written;
101 std::memmove(
102 block_buffer.data() + padding, block_buffer.data(), bytes_written);
103 std::fill(block_buffer.data(), block_buffer.data() + padding, 0);
104
105 } else {
106 std::fill(block_buffer.data() + bytes_written,
107 block_buffer.data() + block.compressed_length,
108 0);
109 }
110 }
111 TEST_EQ(sink(block_buffer.data(), block_buffer.size()),
112 block_buffer.size());
113 }
114 // Any trailing data will be copied to the output buffer.
115 TEST_EQ(
116 sink(reinterpret_cast<const uint8_t*>(blob.data()) + uncompressed_size,
117 blob.size() - uncompressed_size),
118 blob.size() - uncompressed_size);
119 return true;
120 }
121
TryCompressBlob(std::string_view blob,const std::vector<CompressedBlock> & block_info,const bool zero_padding_enabled,const CompressionAlgorithm compression_algo)122 Blob TryCompressBlob(std::string_view blob,
123 const std::vector<CompressedBlock>& block_info,
124 const bool zero_padding_enabled,
125 const CompressionAlgorithm compression_algo) {
126 size_t uncompressed_size = 0;
127 size_t compressed_size = 0;
128 for (const auto& block : block_info) {
129 CHECK_EQ(uncompressed_size, block.uncompressed_offset)
130 << "Compressed block info is expected to be sorted.";
131 uncompressed_size += block.uncompressed_length;
132 compressed_size += block.compressed_length;
133 }
134 TEST_EQ(uncompressed_size, blob.size());
135 Blob output;
136 output.reserve(utils::RoundUp(compressed_size, kBlockSize));
137 if (!TryCompressBlob(blob,
138 block_info,
139 zero_padding_enabled,
140 compression_algo,
141 [&output](const uint8_t* data, size_t size) {
142 output.insert(output.end(), data, data + size);
143 return size;
144 })) {
145 return {};
146 }
147
148 return output;
149 }
150
TryDecompressBlob(std::string_view blob,const std::vector<CompressedBlock> & block_info,const bool zero_padding_enabled)151 Blob TryDecompressBlob(std::string_view blob,
152 const std::vector<CompressedBlock>& block_info,
153 const bool zero_padding_enabled) {
154 if (block_info.empty()) {
155 return {};
156 }
157 size_t uncompressed_size = 0;
158 size_t compressed_size = 0;
159 for (const auto& block : block_info) {
160 CHECK_EQ(uncompressed_size, block.uncompressed_offset)
161 << " Compressed block info is expected to be sorted, expected offset "
162 << uncompressed_size << ", actual block " << block;
163 uncompressed_size += block.uncompressed_length;
164 compressed_size += block.compressed_length;
165 }
166 if (blob.size() < compressed_size) {
167 LOG(INFO) << "File is chunked. Skip lz4 decompress. Expected size: "
168 << compressed_size << ", actual size: " << blob.size();
169 return {};
170 }
171 Blob output;
172 output.reserve(uncompressed_size);
173 size_t compressed_offset = 0;
174 for (const auto& block : block_info) {
175 std::string_view cluster =
176 blob.substr(compressed_offset, block.compressed_length);
177 if (!block.IsCompressed()) {
178 CHECK_NE(cluster.size(), 0UL);
179 output.insert(output.end(), cluster.begin(), cluster.end());
180 compressed_offset += cluster.size();
181 continue;
182 }
183 size_t inputmargin = 0;
184 if (zero_padding_enabled) {
185 while (inputmargin < std::min(kBlockSize, cluster.size()) &&
186 cluster[inputmargin] == 0) {
187 inputmargin++;
188 }
189 }
190 output.resize(output.size() + block.uncompressed_length);
191
192 const auto bytes_decompressed = LZ4_decompress_safe_partial(
193 cluster.data() + inputmargin,
194 reinterpret_cast<char*>(output.data()) + output.size() -
195 block.uncompressed_length,
196 cluster.size() - inputmargin,
197 block.uncompressed_length,
198 block.uncompressed_length);
199 if (bytes_decompressed < 0) {
200 LOG(FATAL) << "Failed to decompress, " << bytes_decompressed
201 << ", output_cursor = "
202 << output.size() - block.uncompressed_length
203 << ", input_cursor = " << compressed_offset
204 << ", blob.size() = " << blob.size()
205 << ", cluster_size = " << block.compressed_length
206 << ", dest capacity = " << block.uncompressed_length
207 << ", input margin = " << inputmargin << " "
208 << HashCalculator::SHA256Digest(cluster) << " "
209 << HashCalculator::SHA256Digest(blob);
210 return {};
211 }
212 compressed_offset += block.compressed_length;
213 CHECK_EQ(static_cast<uint64_t>(bytes_decompressed),
214 block.uncompressed_length);
215 }
216 CHECK_EQ(output.size(), uncompressed_size);
217
218 // Trailing data not recorded by compressed block info will be treated as
219 // uncompressed, most of the time these are xattrs or trailing zeros.
220 CHECK_EQ(blob.size(), compressed_offset)
221 << " Unexpected data the end of compressed data ";
222 if (compressed_offset < blob.size()) {
223 output.insert(output.end(), blob.begin() + compressed_offset, blob.end());
224 }
225
226 return output;
227 }
228
TryDecompressBlob(const Blob & blob,const std::vector<CompressedBlock> & block_info,const bool zero_padding_enabled)229 Blob TryDecompressBlob(const Blob& blob,
230 const std::vector<CompressedBlock>& block_info,
231 const bool zero_padding_enabled) {
232 return TryDecompressBlob(
233 ToStringView(blob), block_info, zero_padding_enabled);
234 }
235
operator <<(std::ostream & out,const CompressedBlock & block)236 std::ostream& operator<<(std::ostream& out, const CompressedBlock& block) {
237 out << "CompressedBlock{.uncompressed_offset = " << block.uncompressed_offset
238 << ", .compressed_length = " << block.compressed_length
239 << ", .uncompressed_length = " << block.uncompressed_length << "}";
240 return out;
241 }
242
operator <<(std::ostream & out,const CompressedBlockInfo & info)243 std::ostream& operator<<(std::ostream& out, const CompressedBlockInfo& info) {
244 out << "BlockInfo { compressed_length: " << info.compressed_length()
245 << ", uncompressed_length: " << info.uncompressed_length()
246 << ", uncompressed_offset: " << info.uncompressed_offset();
247 if (!info.sha256_hash().empty()) {
248 out << ", sha256_hash: " << HexEncode(info.sha256_hash());
249 }
250 if (!info.postfix_bspatch().empty()) {
251 out << ", postfix_bspatch: " << info.postfix_bspatch().size();
252 }
253 out << "}";
254 return out;
255 }
256
257 } // namespace chromeos_update_engine
258