Merge "liblp: Add a method to create sparse images of the super partition."
am: 97d3fd8fb0
Change-Id: Ib9ff2dca5d1b4e5c5c714773f111076950996f12
diff --git a/fs_mgr/liblp/Android.bp b/fs_mgr/liblp/Android.bp
index 176671a..1434b21 100644
--- a/fs_mgr/liblp/Android.bp
+++ b/fs_mgr/liblp/Android.bp
@@ -34,6 +34,7 @@
"liblog",
"libcrypto",
"libcrypto_utils",
+ "libsparse",
],
whole_static_libs: [
"libext2_uuid",
diff --git a/fs_mgr/liblp/images.cpp b/fs_mgr/liblp/images.cpp
index c8d9f13..93c5618 100644
--- a/fs_mgr/liblp/images.cpp
+++ b/fs_mgr/liblp/images.cpp
@@ -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 @@
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
diff --git a/fs_mgr/liblp/include/liblp/liblp.h b/fs_mgr/liblp/include/liblp/liblp.h
index 469ef9e..c8d34d9 100644
--- a/fs_mgr/liblp/include/liblp/liblp.h
+++ b/fs_mgr/liblp/include/liblp/liblp.h
@@ -59,6 +59,7 @@
// 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);