ab_generator.cc revision 929461ab11769339108658f2022d068446ca90f7 
1//
2// Copyright (C) 2015 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 "update_engine/payload_generator/ab_generator.h"
18
19#include <algorithm>
20
21#include <base/strings/stringprintf.h>
22
23#include "update_engine/common/hash_calculator.h"
24#include "update_engine/common/utils.h"
25#include "update_engine/payload_consumer/payload_constants.h"
26#include "update_engine/payload_generator/annotated_operation.h"
27#include "update_engine/payload_generator/bzip.h"
28#include "update_engine/payload_generator/delta_diff_generator.h"
29#include "update_engine/payload_generator/delta_diff_utils.h"
30
31using chromeos_update_engine::diff_utils::IsAReplaceOperation;
32using std::string;
33using std::vector;
34
35namespace chromeos_update_engine {
36
37bool ABGenerator::GenerateOperations(
38    const PayloadGenerationConfig& config,
39    const PartitionConfig& old_part,
40    const PartitionConfig& new_part,
41    BlobFileWriter* blob_file,
42    vector<AnnotatedOperation>* aops) {
43  TEST_AND_RETURN_FALSE(old_part.name == new_part.name);
44
45  ssize_t hard_chunk_blocks = (config.hard_chunk_size == -1 ? -1 :
46                               config.hard_chunk_size / config.block_size);
47  size_t soft_chunk_blocks = config.soft_chunk_size / config.block_size;
48
49  aops->clear();
50  TEST_AND_RETURN_FALSE(diff_utils::DeltaReadPartition(aops,
51                                                       old_part,
52                                                       new_part,
53                                                       hard_chunk_blocks,
54                                                       soft_chunk_blocks,
55                                                       config.version,
56                                                       blob_file));
57  LOG(INFO) << "done reading " << new_part.name;
58
59  TEST_AND_RETURN_FALSE(
60      FragmentOperations(config.version, aops, new_part.path, blob_file));
61  SortOperationsByDestination(aops);
62
63  // Use the soft_chunk_size when merging operations to prevent merging all
64  // the operations into a huge one if there's no hard limit.
65  size_t merge_chunk_blocks = soft_chunk_blocks;
66  if (hard_chunk_blocks != -1 &&
67      static_cast<size_t>(hard_chunk_blocks) < soft_chunk_blocks) {
68    merge_chunk_blocks = hard_chunk_blocks;
69  }
70
71  TEST_AND_RETURN_FALSE(MergeOperations(
72      aops, config.version, merge_chunk_blocks, new_part.path, blob_file));
73
74  if (config.version.minor >= kOpSrcHashMinorPayloadVersion)
75    TEST_AND_RETURN_FALSE(AddSourceHash(aops, old_part.path));
76
77  return true;
78}
79
80void ABGenerator::SortOperationsByDestination(
81    vector<AnnotatedOperation>* aops) {
82  sort(aops->begin(), aops->end(), diff_utils::CompareAopsByDestination);
83}
84
85bool ABGenerator::FragmentOperations(const PayloadVersion& version,
86                                     vector<AnnotatedOperation>* aops,
87                                     const string& target_part_path,
88                                     BlobFileWriter* blob_file) {
89  vector<AnnotatedOperation> fragmented_aops;
90  for (const AnnotatedOperation& aop : *aops) {
91    // Only do split if the operation has more than one dst extents.
92    if (aop.op.dst_extents_size() > 1) {
93      if (aop.op.type() == InstallOperation::SOURCE_COPY) {
94        TEST_AND_RETURN_FALSE(SplitSourceCopy(aop, &fragmented_aops));
95        continue;
96      }
97      if (IsAReplaceOperation(aop.op.type())) {
98        TEST_AND_RETURN_FALSE(SplitAReplaceOp(
99            version, aop, target_part_path, &fragmented_aops, blob_file));
100        continue;
101      }
102    }
103    fragmented_aops.push_back(aop);
104  }
105  *aops = std::move(fragmented_aops);
106  return true;
107}
108
109bool ABGenerator::SplitSourceCopy(
110    const AnnotatedOperation& original_aop,
111    vector<AnnotatedOperation>* result_aops) {
112  InstallOperation original_op = original_aop.op;
113  TEST_AND_RETURN_FALSE(original_op.type() == InstallOperation::SOURCE_COPY);
114  // Keeps track of the index of curr_src_ext.
115  int curr_src_ext_index = 0;
116  Extent curr_src_ext = original_op.src_extents(curr_src_ext_index);
117  for (int i = 0; i < original_op.dst_extents_size(); i++) {
118    const Extent& dst_ext = original_op.dst_extents(i);
119    // The new operation which will have only one dst extent.
120    InstallOperation new_op;
121    uint64_t blocks_left = dst_ext.num_blocks();
122    while (blocks_left > 0) {
123      if (curr_src_ext.num_blocks() <= blocks_left) {
124        // If the curr_src_ext is smaller than dst_ext, add it.
125        blocks_left -= curr_src_ext.num_blocks();
126        *(new_op.add_src_extents()) = curr_src_ext;
127        if (curr_src_ext_index + 1 < original_op.src_extents().size()) {
128          curr_src_ext = original_op.src_extents(++curr_src_ext_index);
129        } else {
130          break;
131        }
132      } else {
133        // Split src_exts that are bigger than the dst_ext we're dealing with.
134        Extent first_ext;
135        first_ext.set_num_blocks(blocks_left);
136        first_ext.set_start_block(curr_src_ext.start_block());
137        *(new_op.add_src_extents()) = first_ext;
138        // Keep the second half of the split op.
139        curr_src_ext.set_num_blocks(curr_src_ext.num_blocks() - blocks_left);
140        curr_src_ext.set_start_block(curr_src_ext.start_block() + blocks_left);
141        blocks_left -= first_ext.num_blocks();
142      }
143    }
144    // Fix up our new operation and add it to the results.
145    new_op.set_type(InstallOperation::SOURCE_COPY);
146    *(new_op.add_dst_extents()) = dst_ext;
147
148    AnnotatedOperation new_aop;
149    new_aop.op = new_op;
150    new_aop.name = base::StringPrintf("%s:%d", original_aop.name.c_str(), i);
151    result_aops->push_back(new_aop);
152  }
153  if (curr_src_ext_index != original_op.src_extents().size() - 1) {
154    LOG(FATAL) << "Incorrectly split SOURCE_COPY operation. Did not use all "
155               << "source extents.";
156  }
157  return true;
158}
159
160bool ABGenerator::SplitAReplaceOp(const PayloadVersion& version,
161                                  const AnnotatedOperation& original_aop,
162                                  const string& target_part_path,
163                                  vector<AnnotatedOperation>* result_aops,
164                                  BlobFileWriter* blob_file) {
165  InstallOperation original_op = original_aop.op;
166  TEST_AND_RETURN_FALSE(IsAReplaceOperation(original_op.type()));
167  const bool is_replace = original_op.type() == InstallOperation::REPLACE;
168
169  uint32_t data_offset = original_op.data_offset();
170  for (int i = 0; i < original_op.dst_extents_size(); i++) {
171    const Extent& dst_ext = original_op.dst_extents(i);
172    // Make a new operation with only one dst extent.
173    InstallOperation new_op;
174    *(new_op.add_dst_extents()) = dst_ext;
175    uint32_t data_size = dst_ext.num_blocks() * kBlockSize;
176    new_op.set_dst_length(data_size);
177    // If this is a REPLACE, attempt to reuse portions of the existing blob.
178    if (is_replace) {
179      new_op.set_type(InstallOperation::REPLACE);
180      new_op.set_data_length(data_size);
181      new_op.set_data_offset(data_offset);
182      data_offset += data_size;
183    }
184
185    AnnotatedOperation new_aop;
186    new_aop.op = new_op;
187    new_aop.name = base::StringPrintf("%s:%d", original_aop.name.c_str(), i);
188    TEST_AND_RETURN_FALSE(
189        AddDataAndSetType(&new_aop, version, target_part_path, blob_file));
190
191    result_aops->push_back(new_aop);
192  }
193  return true;
194}
195
196bool ABGenerator::MergeOperations(vector<AnnotatedOperation>* aops,
197                                  const PayloadVersion& version,
198                                  size_t chunk_blocks,
199                                  const string& target_part_path,
200                                  BlobFileWriter* blob_file) {
201  vector<AnnotatedOperation> new_aops;
202  for (const AnnotatedOperation& curr_aop : *aops) {
203    if (new_aops.empty()) {
204      new_aops.push_back(curr_aop);
205      continue;
206    }
207    AnnotatedOperation& last_aop = new_aops.back();
208    bool last_is_a_replace = IsAReplaceOperation(last_aop.op.type());
209
210    if (last_aop.op.dst_extents_size() <= 0 ||
211        curr_aop.op.dst_extents_size() <= 0) {
212      new_aops.push_back(curr_aop);
213      continue;
214    }
215    uint32_t last_dst_idx = last_aop.op.dst_extents_size() - 1;
216    uint32_t last_end_block =
217        last_aop.op.dst_extents(last_dst_idx).start_block() +
218        last_aop.op.dst_extents(last_dst_idx).num_blocks();
219    uint32_t curr_start_block = curr_aop.op.dst_extents(0).start_block();
220    uint32_t combined_block_count =
221        last_aop.op.dst_extents(last_dst_idx).num_blocks() +
222        curr_aop.op.dst_extents(0).num_blocks();
223    bool is_a_replace = IsAReplaceOperation(curr_aop.op.type());
224
225    bool is_delta_op = curr_aop.op.type() == InstallOperation::SOURCE_COPY;
226    if (((is_delta_op && (last_aop.op.type() == curr_aop.op.type())) ||
227         (is_a_replace && last_is_a_replace)) &&
228        last_end_block == curr_start_block &&
229        combined_block_count <= chunk_blocks) {
230      // If the operations have the same type (which is a type that we can
231      // merge), are contiguous, are fragmented to have one destination extent,
232      // and their combined block count would be less than chunk size, merge
233      // them.
234      last_aop.name = base::StringPrintf("%s,%s",
235                                         last_aop.name.c_str(),
236                                         curr_aop.name.c_str());
237
238      if (is_delta_op) {
239        ExtendExtents(last_aop.op.mutable_src_extents(),
240                      curr_aop.op.src_extents());
241        if (curr_aop.op.src_length() > 0)
242          last_aop.op.set_src_length(last_aop.op.src_length() +
243                                     curr_aop.op.src_length());
244      }
245      ExtendExtents(last_aop.op.mutable_dst_extents(),
246                    curr_aop.op.dst_extents());
247      if (curr_aop.op.dst_length() > 0)
248        last_aop.op.set_dst_length(last_aop.op.dst_length() +
249                                   curr_aop.op.dst_length());
250      // Set the data length to zero so we know to add the blob later.
251      if (is_a_replace)
252        last_aop.op.set_data_length(0);
253    } else {
254      // Otherwise just include the extent as is.
255      new_aops.push_back(curr_aop);
256    }
257  }
258
259  // Set the blobs for REPLACE/REPLACE_BZ/REPLACE_XZ operations that have been
260  // merged.
261  for (AnnotatedOperation& curr_aop : new_aops) {
262    if (curr_aop.op.data_length() == 0 &&
263        IsAReplaceOperation(curr_aop.op.type())) {
264      TEST_AND_RETURN_FALSE(
265          AddDataAndSetType(&curr_aop, version, target_part_path, blob_file));
266    }
267  }
268
269  *aops = new_aops;
270  return true;
271}
272
273bool ABGenerator::AddDataAndSetType(AnnotatedOperation* aop,
274                                    const PayloadVersion& version,
275                                    const string& target_part_path,
276                                    BlobFileWriter* blob_file) {
277  TEST_AND_RETURN_FALSE(IsAReplaceOperation(aop->op.type()));
278
279  brillo::Blob data(aop->op.dst_length());
280  vector<Extent> dst_extents;
281  ExtentsToVector(aop->op.dst_extents(), &dst_extents);
282  TEST_AND_RETURN_FALSE(utils::ReadExtents(target_part_path,
283                                           dst_extents,
284                                           &data,
285                                           data.size(),
286                                           kBlockSize));
287
288  brillo::Blob blob;
289  InstallOperation_Type op_type;
290  TEST_AND_RETURN_FALSE(
291      diff_utils::GenerateBestFullOperation(data, version, &blob, &op_type));
292
293  // If the operation doesn't point to a data blob or points to a data blob of
294  // a different type then we add it.
295  if (aop->op.type() != op_type || aop->op.data_length() != blob.size()) {
296    aop->op.set_type(op_type);
297    aop->SetOperationBlob(blob, blob_file);
298  }
299
300  return true;
301}
302
303bool ABGenerator::AddSourceHash(vector<AnnotatedOperation>* aops,
304                                const string& source_part_path) {
305  for (AnnotatedOperation& aop : *aops) {
306    if (aop.op.src_extents_size() == 0)
307      continue;
308
309    vector<Extent> src_extents;
310    ExtentsToVector(aop.op.src_extents(), &src_extents);
311    brillo::Blob src_data, src_hash;
312    uint64_t src_length =
313        aop.op.has_src_length()
314            ? aop.op.src_length()
315            : BlocksInExtents(aop.op.src_extents()) * kBlockSize;
316    TEST_AND_RETURN_FALSE(utils::ReadExtents(
317        source_part_path, src_extents, &src_data, src_length, kBlockSize));
318    TEST_AND_RETURN_FALSE(HashCalculator::RawHashOfData(src_data, &src_hash));
319    aop.op.set_src_sha256_hash(src_hash.data(), src_hash.size());
320  }
321  return true;
322}
323
324}  // namespace chromeos_update_engine
325