Parse Android .map files for unknown filesystem.
When generating a filesystem during the Android build, we also generate
a text file with .map extension with the list of files and the blocks
in the filesystem they are located.
For filesystems unsupported in delta_generator (like squashfs) we use
this text file to produce efficient delta payloads.
Bug: 28150981
Test: Added unittest for parsing. Generated a delta payload of a squashfs image.
Change-Id: I154e72ac785c6f508290daa901fa7958b446c010
diff --git a/payload_generator/mapfile_filesystem.cc b/payload_generator/mapfile_filesystem.cc
new file mode 100644
index 0000000..f4f0804
--- /dev/null
+++ b/payload_generator/mapfile_filesystem.cc
@@ -0,0 +1,151 @@
+//
+// Copyright (C) 2016 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.
+//
+
+#include "update_engine/payload_generator/mapfile_filesystem.h"
+
+#include <algorithm>
+#include <map>
+
+#include <base/files/file_util.h>
+#include <base/logging.h>
+#include <base/strings/string_number_conversions.h>
+#include <base/strings/string_split.h>
+#include <brillo/make_unique_ptr.h>
+
+#include "update_engine/common/utils.h"
+#include "update_engine/payload_generator/extent_ranges.h"
+#include "update_engine/payload_generator/extent_utils.h"
+#include "update_engine/update_metadata.pb.h"
+
+using std::string;
+using std::vector;
+
+namespace {
+// The .map file is defined in terms of 4K blocks.
+size_t kMapfileBlockSize = 4096;
+} // namespace
+
+namespace chromeos_update_engine {
+
+std::unique_ptr<MapfileFilesystem> MapfileFilesystem::CreateFromFile(
+ const string& filename, const string& mapfile_filename) {
+ if (filename.empty() || mapfile_filename.empty())
+ return nullptr;
+
+ off_t file_size = utils::FileSize(filename);
+ if (file_size < 0)
+ return nullptr;
+
+ if (file_size % kMapfileBlockSize) {
+ LOG(ERROR) << "Image file " << filename << " has a size of " << file_size
+ << " which is not multiple of " << kMapfileBlockSize;
+ return nullptr;
+ }
+ off_t num_blocks = file_size / kMapfileBlockSize;
+
+ if (!utils::FileExists(mapfile_filename.c_str())) {
+ LOG(ERROR) << "File " << mapfile_filename << " doesn't exist";
+ return nullptr;
+ }
+
+ return brillo::make_unique_ptr(
+ new MapfileFilesystem(mapfile_filename, num_blocks));
+}
+
+MapfileFilesystem::MapfileFilesystem(const string& mapfile_filename,
+ off_t num_blocks)
+ : mapfile_filename_(mapfile_filename), num_blocks_(num_blocks) {}
+
+size_t MapfileFilesystem::GetBlockSize() const {
+ return kMapfileBlockSize;
+}
+
+size_t MapfileFilesystem::GetBlockCount() const {
+ return num_blocks_;
+}
+
+bool MapfileFilesystem::GetFiles(vector<File>* files) const {
+ files->clear();
+
+ string file_data;
+ if (!base::ReadFileToString(base::FilePath(mapfile_filename_), &file_data)) {
+ LOG(ERROR) << "Unable to read .map file: " << mapfile_filename_;
+ return false;
+ }
+
+ // Iterate over all the lines in the file and generate one File entry per
+ // line.
+ vector<base::StringPiece> lines = base::SplitStringPiece(
+ file_data, "\n", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL);
+ for (const base::StringPiece& line : lines) {
+ File mapped_file;
+
+ mapped_file.extents = {};
+ size_t delim, last_delim = line.size();
+ while ((delim = line.rfind(' ', last_delim - 1)) != string::npos) {
+ string blocks =
+ line.substr(delim + 1, last_delim - (delim + 1)).as_string();
+ size_t dash = blocks.find('-', 0);
+ uint64_t block_start, block_end;
+ if (dash == string::npos && base::StringToUint64(blocks, &block_start)) {
+ mapped_file.extents.push_back(ExtentForRange(block_start, 1));
+ } else if (dash != string::npos &&
+ base::StringToUint64(blocks.substr(0, dash), &block_start) &&
+ base::StringToUint64(blocks.substr(dash + 1), &block_end)) {
+ if (block_end < block_start) {
+ LOG(ERROR) << "End block " << block_end
+ << " is smaller than start block " << block_start
+ << std::endl
+ << line;
+ return false;
+ }
+ if (block_end > static_cast<uint64_t>(num_blocks_)) {
+ LOG(ERROR) << "The end block " << block_end
+ << " is past the end of the file of " << num_blocks_
+ << " blocks" << std::endl
+ << line;
+ return false;
+ }
+ mapped_file.extents.push_back(
+ ExtentForRange(block_start, block_end - block_start + 1));
+ } else {
+ // If we can't parse N or N-M, we assume the block is actually part of
+ // the name of the file.
+ break;
+ }
+ last_delim = delim;
+ }
+ // We parsed the blocks from the end of the line, so we need to reverse
+ // the Extents in the file.
+ std::reverse(mapped_file.extents.begin(), mapped_file.extents.end());
+
+ if (last_delim == string::npos)
+ continue;
+ mapped_file.name = line.substr(0, last_delim).as_string();
+
+ files->push_back(mapped_file);
+ }
+
+ return true;
+}
+
+bool MapfileFilesystem::LoadSettings(brillo::KeyValueStore* store) const {
+ // Settings not supported in mapfile since the storage format is unknown.
+ LOG(ERROR) << "mapfile doesn't support LoadSettings().";
+ return false;
+}
+
+} // namespace chromeos_update_engine