Merge "liblp: Add a method to create sparse images of the super partition." (97d3fd8f) · Commits · e / os / android_system_core

fs_mgr/liblp/Android.bp

+1 −0

Original line number	Diff line number	Diff line
		@@ -34,6 +34,7 @@ cc_library_static {
		"liblog",
		"libcrypto",
		"libcrypto_utils",
		"libsparse",
		],
		whole_static_libs: [
		"libext2_uuid",

fs_mgr/liblp/images.cpp

+113 −0

Original line number	Diff line number	Diff line
		@@ -16,8 +16,11 @@

		#include "images.h"

		#include <limits.h>

		#include <android-base/file.h>
		#include <android-base/unique_fd.h>
		#include <sparse/sparse.h>

		#include "reader.h"
		#include "utility.h"
		@@ -75,5 +78,115 @@ bool WriteToImageFile(const char* file, const LpMetadata& input) {
		return WriteToImageFile(fd, input);
		}

		// We use an object to build the sparse file since it requires that data
		// pointers be held alive until the sparse file is destroyed. It's easier
		// to do this when the data pointers are all in one place.
		class SparseBuilder {
		public:
		explicit SparseBuilder(const LpMetadata& metadata);

		bool Build();
		bool Export(const char* file);
		bool IsValid() const { return file_ != nullptr; }

		private:
		bool AddData(const std::string& blob, uint32_t block);

		const LpMetadata& metadata_;
		const LpMetadataGeometry& geometry_;
		std::unique_ptr<sparse_file, decltype(&sparse_file_destroy)> file_;
		std::string geometry_blob_;
		std::string metadata_blob_;
		};

		SparseBuilder::SparseBuilder(const LpMetadata& metadata)
		: metadata_(metadata),
		geometry_(metadata.geometry),
		file_(sparse_file_new(LP_SECTOR_SIZE, geometry_.block_device_size), sparse_file_destroy) {}

		bool SparseBuilder::Export(const char* file) {
		android::base::unique_fd fd(open(file, O_CREAT \| O_RDWR \| O_TRUNC, 0644));
		if (fd < 0) {
		PERROR << "open failed: " << file;
		return false;
		}
		// No gzip compression; sparseify; no checksum.
		int ret = sparse_file_write(file_.get(), fd, false, true, false);
		if (ret != 0) {
		LERROR << "sparse_file_write failed (error code " << ret << ")";
		return false;
		}
		return true;
		}

		bool SparseBuilder::AddData(const std::string& blob, uint32_t block) {
		void* data = const_cast<char*>(blob.data());
		int ret = sparse_file_add_data(file_.get(), data, blob.size(), block);
		if (ret != 0) {
		LERROR << "sparse_file_add_data failed (error code " << ret << ")";
		return false;
		}
		return true;
		}

		bool SparseBuilder::Build() {
		geometry_blob_ = SerializeGeometry(geometry_);
		geometry_blob_.resize(LP_METADATA_GEOMETRY_SIZE);
		if (!AddData(geometry_blob_, 0)) {
		return false;
		}

		// Metadata immediately follows geometry, and we write the same metadata
		// to all slots.
		uint32_t metadata_block = LP_METADATA_GEOMETRY_SIZE / LP_SECTOR_SIZE;
		metadata_blob_ = SerializeMetadata(metadata_);
		for (size_t i = 0; i < geometry_.metadata_slot_count; i++) {
		if (!AddData(metadata_blob_, metadata_block)) {
		return false;
		}
		metadata_block += geometry_.metadata_max_size / LP_SECTOR_SIZE;
		}

		// The backup area contains all metadata slots, and then geometry. Similar
		// to before we write the metadata to every slot.
		int64_t backup_offset = GetBackupMetadataOffset(geometry_, 0);
		uint64_t backups_start = geometry_.block_device_size + backup_offset;
		uint64_t backup_sector = backups_start / LP_SECTOR_SIZE;
		for (size_t i = 0; i < geometry_.metadata_slot_count; i++) {
		if (!AddData(metadata_blob_, backup_sector)) {
		return false;
		}
		backup_sector += geometry_.metadata_max_size / LP_SECTOR_SIZE;
		}
		if (!AddData(geometry_blob_, backup_sector)) {
		return false;
		}
		return true;
		}

		bool WriteToSparseFile(const char* file, const LpMetadata& metadata) {
		uint64_t num_blocks =
		AlignTo(metadata.geometry.block_device_size, LP_SECTOR_SIZE) / LP_SECTOR_SIZE;
		if (num_blocks >= UINT_MAX) {
		// libsparse counts blocks in unsigned 32-bit integers, but our block
		// size is rather low (512 bytes), since we operate in sectors.
		// Therefore the maximum block device size we can represent with a
		// sparse file is 2TB for now.
		LERROR << "Block device is too large to encode with libsparse.";
		return false;
		}

		SparseBuilder builder(metadata);
		if (!builder.IsValid()) {
		LERROR << "Could not allocate sparse file of size " << metadata.geometry.block_device_size;
		return false;
		}
		if (!builder.Build()) {
		return false;
		}

		return builder.Export(file);
		}

		} // namespace fs_mgr
		} // namespace android

fs_mgr/liblp/include/liblp/liblp.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -59,6 +59,7 @@ std::unique_ptr<LpMetadata> ReadMetadata(const char* block_device, uint32_t slot

		// Read/Write logical partition metadata to an image file, for diagnostics or
		// flashing.
		bool WriteToSparseFile(const char* file, const LpMetadata& metadata);
		bool WriteToImageFile(const char* file, const LpMetadata& metadata);
		std::unique_ptr<LpMetadata> ReadFromImageFile(const char* file);