AU: Delta Diff Generator
Adds a class that can take two root filesystem image and generate a
delta between them. Currently it's not very well tested, but this will
improve once the diff applicator is written.
Also, an executable to run the generator.
Other changes:
- Stop leaking loop devices in unittests
- extent mapper: support sparse files, ability to get FS block size
- AppendBlockToExtents support sparse files
- subprocess more verbose on errors
- add WriteAll to utils (WriteAll avoids short-write() returns)
- mkstemp wrapper for ease of use
- VectorIndexOf, finds index of an element in a vector
Review URL: http://codereview.chromium.org/891002
diff --git a/delta_diff_generator.cc b/delta_diff_generator.cc
index 4114c32..4181057 100644
--- a/delta_diff_generator.cc
+++ b/delta_diff_generator.cc
@@ -3,3 +3,863 @@
// found in the LICENSE file.
#include "update_engine/delta_diff_generator.h"
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <algorithm>
+#include <set>
+#include <string>
+#include <utility>
+#include <vector>
+#include <bzlib.h>
+#include "chromeos/obsolete_logging.h"
+#include "update_engine/bzip.h"
+#include "update_engine/cycle_breaker.h"
+#include "update_engine/extent_mapper.h"
+#include "update_engine/file_writer.h"
+#include "update_engine/filesystem_iterator.h"
+#include "update_engine/graph_types.h"
+#include "update_engine/graph_utils.h"
+#include "update_engine/subprocess.h"
+#include "update_engine/topological_sort.h"
+#include "update_engine/update_metadata.pb.h"
+#include "update_engine/utils.h"
+
+using std::make_pair;
+using std::min;
+using std::set;
+using std::string;
+using std::vector;
+
+namespace chromeos_update_engine {
+
+typedef DeltaDiffGenerator::Block Block;
+
+namespace {
+const size_t kBlockSize = 4096;
+const char* const kBsdiffPath = "/usr/bin/bsdiff";
+const uint64 kVersionNumber = 1;
+const char* const kDeltaMagic = "CrAU";
+
+// Stores all Extents for a file into 'out'. Returns true on success.
+bool GatherExtents(const string& path,
+ google::protobuf::RepeatedPtrField<Extent>* out) {
+ vector<Extent> extents;
+ TEST_AND_RETURN_FALSE(extent_mapper::ExtentsForFileFibmap(path, &extents));
+ DeltaDiffGenerator::StoreExtents(extents, out);
+ return true;
+}
+
+// Runs the bsdiff tool on two files and returns the resulting delta in
+// 'out'. Returns true on success.
+bool BsdiffFiles(const string& old_file,
+ const string& new_file,
+ vector<char>* out) {
+ const string kPatchFile = "/tmp/delta.patchXXXXXX";
+ string patch_file_path;
+
+ TEST_AND_RETURN_FALSE(
+ utils::MakeTempFile(kPatchFile, &patch_file_path, NULL));
+
+ vector<string> cmd;
+ cmd.push_back(kBsdiffPath);
+ cmd.push_back(old_file);
+ cmd.push_back(new_file);
+ cmd.push_back(patch_file_path);
+
+ int rc = 1;
+ vector<char> patch_file;
+ TEST_AND_RETURN_FALSE(Subprocess::SynchronousExec(cmd, &rc));
+ TEST_AND_RETURN_FALSE(rc == 0);
+ TEST_AND_RETURN_FALSE(utils::ReadFile(patch_file_path, out));
+ unlink(patch_file_path.c_str());
+ return true;
+}
+
+// The blocks vector contains a reader and writer for each block on the
+// filesystem that's being in-place updated. We populate the reader/writer
+// fields of blocks by calling this function.
+// For each block in 'operation' that is read or written, find that block
+// in 'blocks' and set the reader/writer field to the vertex passed.
+// 'graph' is not strictly necessary, but useful for printing out
+// error messages.
+bool AddInstallOpToBlocksVector(
+ const DeltaArchiveManifest_InstallOperation& operation,
+ vector<Block>* blocks,
+ const Graph& graph,
+ Vertex::Index vertex) {
+ LOG(INFO) << "AddInstallOpToBlocksVector(" << vertex << "), "
+ << graph[vertex].file_name;
+ // See if this is already present.
+ TEST_AND_RETURN_FALSE(operation.dst_extents_size() > 0);
+
+ enum BlockField { READER = 0, WRITER, BLOCK_FIELD_COUNT };
+ for (int field = READER; field < BLOCK_FIELD_COUNT; field++) {
+ const int extents_size =
+ (field == READER) ? operation.src_extents_size() :
+ operation.dst_extents_size();
+ const char* past_participle = (field == READER) ? "read" : "written";
+ const google::protobuf::RepeatedPtrField<Extent>& extents =
+ (field == READER) ? operation.src_extents() : operation.dst_extents();
+ Vertex::Index Block::*access_type =
+ (field == READER) ? &Block::reader : &Block::writer;
+
+ for (int i = 0; i < extents_size; i++) {
+ const Extent& extent = extents.Get(i);
+ if (extent.start_block() == kSparseHole) {
+ // Hole in sparse file. skip
+ continue;
+ }
+ for (uint64_t block = extent.start_block();
+ block < (extent.start_block() + extent.num_blocks()); block++) {
+ LOG(INFO) << "ext: " << i << " block: " << block;
+ if ((*blocks)[block].*access_type != Vertex::kInvalidIndex) {
+ LOG(FATAL) << "Block " << block << " is already "
+ << past_participle << " by "
+ << (*blocks)[block].*access_type << "("
+ << graph[(*blocks)[block].*access_type].file_name
+ << ") and also " << vertex << "("
+ << graph[vertex].file_name << ")";
+ }
+ (*blocks)[block].*access_type = vertex;
+ }
+ }
+ }
+ return true;
+}
+
+// For a given regular file which must exist at new_root + path, and may
+// exist at old_root + path, creates a new InstallOperation and adds it to
+// the graph. Also, populates the 'blocks' array as necessary.
+// Also, writes the data necessary to send the file down to the client
+// into data_fd, which has length *data_file_size. *data_file_size is
+// updated appropriately.
+// Returns true on success.
+bool DeltaReadFile(Graph* graph,
+ vector<Block>* blocks,
+ const string& old_root,
+ const string& new_root,
+ const string& path, // within new_root
+ int data_fd,
+ off_t* data_file_size) {
+ vector<char> data;
+ DeltaArchiveManifest_InstallOperation operation;
+
+ TEST_AND_RETURN_FALSE(DeltaDiffGenerator::ReadFileToDiff(old_root + path,
+ new_root + path,
+ &data,
+ &operation));
+
+ // Write the data
+ if (operation.type() != DeltaArchiveManifest_InstallOperation_Type_MOVE) {
+ operation.set_data_offset(*data_file_size);
+ operation.set_data_length(data.size());
+ }
+
+ TEST_AND_RETURN_FALSE(utils::WriteAll(data_fd, &data[0], data.size()));
+ *data_file_size += data.size();
+
+ // Now, insert into graph and blocks vector
+ graph->resize(graph->size() + 1);
+ graph->back().op = operation;
+ CHECK(graph->back().op.has_type());
+ graph->back().file_name = path;
+
+ TEST_AND_RETURN_FALSE(AddInstallOpToBlocksVector(graph->back().op,
+ blocks,
+ *graph,
+ graph->size() - 1));
+ return true;
+}
+
+// For each regular file within new_root, creates a node in the graph,
+// determines the best way to compress it (REPLACE, REPLACE_BZ, COPY, BSDIFF),
+// and writes any necessary data to the end of data_fd.
+bool DeltaReadFiles(Graph* graph,
+ vector<Block>* blocks,
+ const string& old_root,
+ const string& new_root,
+ int data_fd,
+ off_t* data_file_size) {
+ set<ino_t> visited_inodes;
+ for (FilesystemIterator fs_iter(new_root,
+ utils::SetWithValue<string>("/lost+found"));
+ !fs_iter.IsEnd(); fs_iter.Increment()) {
+ if (!S_ISREG(fs_iter.GetStat().st_mode))
+ continue;
+
+ // Make sure we visit each inode only once.
+ if (utils::SetContainsKey(visited_inodes, fs_iter.GetStat().st_ino))
+ continue;
+ visited_inodes.insert(fs_iter.GetStat().st_ino);
+ if (fs_iter.GetStat().st_size == 0)
+ continue;
+
+ LOG(INFO) << "Encoding file " << fs_iter.GetPartialPath();
+
+ TEST_AND_RETURN_FALSE(DeltaReadFile(graph,
+ blocks,
+ old_root,
+ new_root,
+ fs_iter.GetPartialPath(),
+ data_fd,
+ data_file_size));
+ }
+ return true;
+}
+
+// Attempts to find block_count blocks to use as scratch space.
+// Returns true on success.
+// Right now we return exactly as many blocks as are required.
+// TODO(adlr): consider returning all scratch blocks,
+// even if there are extras, to make it easier for a scratch allocator
+// to find contiguous regions for specific scratch writes.
+bool FindScratchSpace(const vector<Block>& blocks,
+ vector<Block>::size_type block_count,
+ vector<Extent>* out) {
+ // Scan blocks for blocks that are neither read nor written.
+ // If we don't find enough of those, return false.
+ // TODO(adlr): return blocks that are written by
+ // operations that don't have incoming edges (and thus, can be
+ // deferred until all old blocks are read by other operations).
+ vector<Extent> ret;
+ vector<Block>::size_type blocks_found = 0;
+ for (vector<Block>::size_type i = 0;
+ i < blocks.size() && blocks_found < block_count; i++) {
+ if (blocks[i].reader == Vertex::kInvalidIndex &&
+ blocks[i].writer == Vertex::kInvalidIndex) {
+ graph_utils::AppendBlockToExtents(&ret, i);
+ blocks_found++;
+ }
+ }
+ if (blocks_found == block_count) {
+ LOG(INFO) << "returning " << blocks_found << " scratch blocks";
+ out->swap(ret);
+ return true;
+ }
+ return false;
+}
+
+// This class takes a collection of Extents and allows the client to
+// allocate space from these extents. The client must not request more
+// space then exists in the source extents. Space is allocated from the
+// beginning of the source extents on; no consideration is paid to
+// fragmentation.
+class LinearExtentAllocator {
+ public:
+ explicit LinearExtentAllocator(const vector<Extent>& extents)
+ : extents_(extents),
+ extent_index_(0),
+ extent_blocks_allocated_(0) {}
+ vector<Extent> Allocate(const uint64_t block_count) {
+ vector<Extent> ret;
+ for (uint64_t blocks = 0; blocks < block_count; blocks++) {
+ CHECK_LT(extent_index_, extents_.size());
+ CHECK_LT(extent_blocks_allocated_, extents_[extent_index_].num_blocks());
+ graph_utils::AppendBlockToExtents(
+ &ret,
+ extents_[extent_index_].start_block() + extent_blocks_allocated_);
+ extent_blocks_allocated_++;
+ if (extent_blocks_allocated_ >= extents_[extent_index_].num_blocks()) {
+ extent_blocks_allocated_ = 0;
+ extent_index_++;
+ }
+ }
+ return ret;
+ }
+ private:
+ const vector<Extent> extents_;
+ vector<Extent>::size_type extent_index_; // current Extent
+ // number of blocks allocated from the current extent
+ uint64_t extent_blocks_allocated_;
+};
+
+// Reads blocks from image_path that are not yet marked as being written
+// in the blocks array. These blocks that remain are non-file-data blocks.
+// In the future we might consider intelligent diffing between this data
+// and data in the previous image, but for now we just bzip2 compress it
+// and include it in the update.
+// Creates a new node in the graph to write these blocks and writes the
+// appropriate blob to blobs_fd. Reads and updates blobs_length;
+bool ReadUnwrittenBlocks(const vector<Block>& blocks,
+ int blobs_fd,
+ off_t* blobs_length,
+ const string& image_path,
+ DeltaArchiveManifest_InstallOperation* out_op) {
+ int image_fd = open(image_path.c_str(), O_RDONLY, 000);
+ TEST_AND_RETURN_FALSE_ERRNO(image_fd >= 0);
+ ScopedFdCloser image_fd_closer(&image_fd);
+
+ string temp_file_path;
+ TEST_AND_RETURN_FALSE(utils::MakeTempFile("/tmp/CrAU_temp_data.XXXXXX",
+ &temp_file_path,
+ NULL));
+
+ FILE* file = fopen(temp_file_path.c_str(), "w");
+ TEST_AND_RETURN_FALSE(file);
+ int err = BZ_OK;
+
+ BZFILE* bz_file = BZ2_bzWriteOpen(&err,
+ file,
+ 9, // max compression
+ 0, // verbosity
+ 0); // default work factor
+ TEST_AND_RETURN_FALSE(err == BZ_OK);
+
+ vector<Extent> extents;
+ vector<Block>::size_type block_count = 0;
+
+ LOG(INFO) << "Appending left over blocks to extents";
+ for (vector<Block>::size_type i = 0; i < blocks.size(); i++) {
+ if (blocks[i].writer != Vertex::kInvalidIndex)
+ continue;
+ graph_utils::AppendBlockToExtents(&extents, i);
+ block_count++;
+ }
+
+ // Code will handle 'buf' at any size that's a multiple of kBlockSize,
+ // so we arbitrarily set it to 1024 * kBlockSize.
+ vector<char> buf(1024 * kBlockSize);
+
+ LOG(INFO) << "Reading left over blocks";
+ vector<Block>::size_type blocks_copied_count = 0;
+
+ // For each extent in extents, write the data into BZ2_bzWrite which
+ // sends it to an output file.
+ // We use the temporary buffer 'buf' to hold the data, which may be
+ // smaller than the extent, so in that case we have to loop to get
+ // the extent's data (that's the inner while loop).
+ for (vector<Extent>::const_iterator it = extents.begin();
+ it != extents.end(); ++it) {
+ vector<Block>::size_type blocks_read = 0;
+ while (blocks_read < it->num_blocks()) {
+ const int copy_block_cnt =
+ min(buf.size() / kBlockSize,
+ static_cast<vector<char>::size_type>(
+ it->num_blocks() - blocks_read));
+ ssize_t rc = pread(image_fd,
+ &buf[0],
+ copy_block_cnt * kBlockSize,
+ (it->start_block() + blocks_read) * kBlockSize);
+ TEST_AND_RETURN_FALSE_ERRNO(rc >= 0);
+ TEST_AND_RETURN_FALSE(static_cast<size_t>(rc) ==
+ copy_block_cnt * kBlockSize);
+ BZ2_bzWrite(&err, bz_file, &buf[0], copy_block_cnt * kBlockSize);
+ TEST_AND_RETURN_FALSE(err == BZ_OK);
+ blocks_read += copy_block_cnt;
+ blocks_copied_count += copy_block_cnt;
+ LOG(INFO) << "progress: " << ((float)blocks_copied_count)/block_count;
+ }
+ }
+ BZ2_bzWriteClose(&err, bz_file, 0, NULL, NULL);
+ TEST_AND_RETURN_FALSE(err == BZ_OK);
+ bz_file = NULL;
+ TEST_AND_RETURN_FALSE_ERRNO(0 == fclose(file));
+ file = NULL;
+
+ vector<char> compressed_data;
+ LOG(INFO) << "Reading compressed data off disk";
+ TEST_AND_RETURN_FALSE(utils::ReadFile(temp_file_path, &compressed_data));
+ TEST_AND_RETURN_FALSE(unlink(temp_file_path.c_str()) == 0);
+
+ // Add node to graph to write these blocks
+ out_op->set_type(DeltaArchiveManifest_InstallOperation_Type_REPLACE_BZ);
+ out_op->set_data_offset(*blobs_length);
+ out_op->set_data_length(compressed_data.size());
+ *blobs_length += compressed_data.size();
+ out_op->set_dst_length(kBlockSize * block_count);
+ DeltaDiffGenerator::StoreExtents(extents, out_op->mutable_dst_extents());
+
+ TEST_AND_RETURN_FALSE(utils::WriteAll(blobs_fd,
+ &compressed_data[0],
+ compressed_data.size()));
+ LOG(INFO) << "done with extra blocks";
+ return true;
+}
+
+// Writes the uint64 passed in in host-endian to the file as big-endian.
+// Returns true on success.
+bool WriteUint64AsBigEndian(FileWriter* writer, const uint64 value) {
+ uint64 value_be = htobe64(value);
+ TEST_AND_RETURN_FALSE(writer->Write(&value_be, sizeof(value_be)) ==
+ sizeof(value_be));
+ return true;
+}
+
+// Adds each operation from the graph to the manifest in the order
+// specified by 'order'.
+void InstallOperationsToManifest(
+ const Graph& graph,
+ const vector<Vertex::Index>& order,
+ DeltaArchiveManifest* out_manifest) {
+ for (vector<Vertex::Index>::const_iterator it = order.begin();
+ it != order.end(); ++it) {
+ DeltaArchiveManifest_InstallOperation* op =
+ out_manifest->add_install_operations();
+ *op = graph[*it].op;
+ }
+}
+
+void CheckGraph(const Graph& graph) {
+ for (Graph::const_iterator it = graph.begin(); it != graph.end(); ++it) {
+ CHECK(it->op.has_type());
+ }
+}
+
+} // namespace {}
+
+bool DeltaDiffGenerator::ReadFileToDiff(
+ const string& old_filename,
+ const string& new_filename,
+ vector<char>* out_data,
+ DeltaArchiveManifest_InstallOperation* out_op) {
+ // Read new data in
+ vector<char> new_data;
+ TEST_AND_RETURN_FALSE(utils::ReadFile(new_filename, &new_data));
+
+ TEST_AND_RETURN_FALSE(!new_data.empty());
+
+ vector<char> new_data_bz;
+ TEST_AND_RETURN_FALSE(BzipCompress(new_data, &new_data_bz));
+ CHECK(!new_data_bz.empty());
+
+ vector<char> data; // Data blob that will be written to delta file.
+
+ DeltaArchiveManifest_InstallOperation operation;
+ size_t current_best_size = 0;
+ if (new_data.size() <= new_data_bz.size()) {
+ operation.set_type(DeltaArchiveManifest_InstallOperation_Type_REPLACE);
+ current_best_size = new_data.size();
+ data = new_data;
+ } else {
+ operation.set_type(DeltaArchiveManifest_InstallOperation_Type_REPLACE_BZ);
+ current_best_size = new_data_bz.size();
+ data = new_data_bz;
+ }
+
+ // Do we have an original file to consider?
+ struct stat old_stbuf;
+ if (0 != stat(old_filename.c_str(), &old_stbuf)) {
+ // If stat-ing the old file fails, it should be because it doesn't exist.
+ TEST_AND_RETURN_FALSE(errno == ENOTDIR || errno == ENOENT);
+ } else {
+ // Read old data
+ vector<char> old_data;
+ TEST_AND_RETURN_FALSE(utils::ReadFile(old_filename, &old_data));
+ if (old_data == new_data) {
+ // No change in data.
+ operation.set_type(DeltaArchiveManifest_InstallOperation_Type_MOVE);
+ current_best_size = 0;
+ data.clear();
+ } else {
+ // Try bsdiff of old to new data
+ vector<char> bsdiff_delta;
+ TEST_AND_RETURN_FALSE(
+ BsdiffFiles(old_filename, new_filename, &bsdiff_delta));
+ CHECK_GT(bsdiff_delta.size(), 0);
+ if (bsdiff_delta.size() < current_best_size) {
+ operation.set_type(DeltaArchiveManifest_InstallOperation_Type_BSDIFF);
+ current_best_size = bsdiff_delta.size();
+
+ data = bsdiff_delta;
+ }
+ }
+ }
+
+ // Set parameters of the operations
+ CHECK_EQ(data.size(), current_best_size);
+
+ if (operation.type() == DeltaArchiveManifest_InstallOperation_Type_MOVE ||
+ operation.type() == DeltaArchiveManifest_InstallOperation_Type_BSDIFF) {
+ TEST_AND_RETURN_FALSE(
+ GatherExtents(old_filename, operation.mutable_src_extents()));
+ operation.set_src_length(old_stbuf.st_size);
+ }
+
+ TEST_AND_RETURN_FALSE(
+ GatherExtents(new_filename, operation.mutable_dst_extents()));
+ operation.set_dst_length(new_data.size());
+
+ out_data->swap(data);
+ *out_op = operation;
+
+ return true;
+}
+
+void DeltaDiffGenerator::SubstituteBlocks(
+ DeltaArchiveManifest_InstallOperation* op,
+ const vector<Extent>& remove_extents,
+ const vector<Extent>& replace_extents) {
+ // First, expand out the blocks that op reads from
+ vector<uint64> read_blocks;
+ for (int i = 0; i < op->src_extents_size(); i++) {
+ const Extent& extent = op->src_extents(i);
+ if (extent.start_block() == kSparseHole) {
+ read_blocks.resize(read_blocks.size() + extent.num_blocks(), kSparseHole);
+ } else {
+ for (uint64 block = extent.start_block();
+ block < (extent.start_block() + extent.num_blocks()); block++) {
+ read_blocks.push_back(block);
+ }
+ }
+ }
+ {
+ // Expand remove_extents and replace_extents
+ vector<uint64> remove_extents_expanded;
+ for (vector<Extent>::const_iterator it = remove_extents.begin();
+ it != remove_extents.end(); ++it) {
+ const Extent& extent = *it;
+ for (uint64 block = extent.start_block();
+ block < (extent.start_block() + extent.num_blocks()); block++) {
+ remove_extents_expanded.push_back(block);
+ }
+ }
+ vector<uint64> replace_extents_expanded;
+ for (vector<Extent>::const_iterator it = replace_extents.begin();
+ it != replace_extents.end(); ++it) {
+ const Extent& extent = *it;
+ for (uint64 block = extent.start_block();
+ block < (extent.start_block() + extent.num_blocks()); block++) {
+ replace_extents_expanded.push_back(block);
+ }
+ }
+ CHECK_EQ(remove_extents_expanded.size(), replace_extents_expanded.size());
+ for (vector<uint64>::size_type i = 0;
+ i < replace_extents_expanded.size(); i++) {
+ vector<uint64>::size_type index = 0;
+ CHECK(utils::VectorIndexOf(read_blocks,
+ remove_extents_expanded[i],
+ &index));
+ CHECK(read_blocks[index] == remove_extents_expanded[i]);
+ read_blocks[index] = replace_extents_expanded[i];
+ }
+ }
+ // Convert read_blocks back to extents
+ op->clear_src_extents();
+ vector<Extent> new_extents;
+ for (vector<uint64>::const_iterator it = read_blocks.begin();
+ it != read_blocks.end(); ++it) {
+ graph_utils::AppendBlockToExtents(&new_extents, *it);
+ }
+ DeltaDiffGenerator::StoreExtents(new_extents, op->mutable_src_extents());
+}
+
+bool DeltaDiffGenerator::CutEdges(Graph* graph,
+ const vector<Block>& blocks,
+ const set<Edge>& edges) {
+ // First, find enough scratch space for the edges we'll be cutting.
+ vector<Block>::size_type blocks_required = 0;
+ for (set<Edge>::const_iterator it = edges.begin(); it != edges.end(); ++it) {
+ blocks_required += graph_utils::EdgeWeight(*graph, *it);
+ }
+ vector<Extent> scratch_extents;
+ LOG(INFO) << "requesting " << blocks_required << " blocks of scratch";
+ TEST_AND_RETURN_FALSE(
+ FindScratchSpace(blocks, blocks_required, &scratch_extents));
+ LinearExtentAllocator scratch_allocator(scratch_extents);
+
+ uint64_t scratch_blocks_used = 0;
+ for (set<Edge>::const_iterator it = edges.begin();
+ it != edges.end(); ++it) {
+ vector<Extent> old_extents =
+ (*graph)[it->first].out_edges[it->second].extents;
+ // Choose some scratch space
+ scratch_blocks_used += graph_utils::EdgeWeight(*graph, *it);
+ LOG(INFO) << "using " << graph_utils::EdgeWeight(*graph, *it)
+ << " scratch blocks ("
+ << scratch_blocks_used << ")";
+ vector<Extent> scratch =
+ scratch_allocator.Allocate(graph_utils::EdgeWeight(*graph, *it));
+ // create vertex to copy original->scratch
+ graph->resize(graph->size() + 1);
+
+ // make node depend on the copy operation
+ (*graph)[it->first].out_edges.insert(make_pair(graph->size() - 1,
+ EdgeProperties()));
+
+ // Set src/dst extents and other proto variables for copy operation
+ graph->back().op.set_type(DeltaArchiveManifest_InstallOperation_Type_MOVE);
+ DeltaDiffGenerator::StoreExtents(
+ (*graph)[it->first].out_edges[it->second].extents,
+ graph->back().op.mutable_src_extents());
+ DeltaDiffGenerator::StoreExtents(scratch,
+ graph->back().op.mutable_dst_extents());
+ graph->back().op.set_src_length(
+ graph_utils::EdgeWeight(*graph, *it) * kBlockSize);
+ graph->back().op.set_dst_length(graph->back().op.src_length());
+
+ // make the dest node read from the scratch space
+ DeltaDiffGenerator::SubstituteBlocks(
+ &((*graph)[it->second].op),
+ (*graph)[it->first].out_edges[it->second].extents,
+ scratch);
+
+ // delete the old edge
+ CHECK_EQ(1, (*graph)[it->first].out_edges.erase(it->second));
+ }
+ return true;
+}
+
+// Stores all Extents in 'extents' into 'out'.
+void DeltaDiffGenerator::StoreExtents(
+ vector<Extent>& extents,
+ google::protobuf::RepeatedPtrField<Extent>* out) {
+ for (vector<Extent>::const_iterator it = extents.begin();
+ it != extents.end(); ++it) {
+ Extent* new_extent = out->Add();
+ *new_extent = *it;
+ }
+}
+
+// Creates all the edges for the graph. Writers of a block point to
+// readers of the same block. This is because for an edge A->B, B
+// must complete before A executes.
+void DeltaDiffGenerator::CreateEdges(Graph* graph,
+ const vector<Block>& blocks) {
+ for (vector<Block>::size_type i = 0; i < blocks.size(); i++) {
+ // Blocks with both a reader and writer get an edge
+ if (blocks[i].reader == Vertex::kInvalidIndex ||
+ blocks[i].writer == Vertex::kInvalidIndex)
+ continue;
+ // Don't have a node depend on itself
+ if (blocks[i].reader == blocks[i].writer)
+ continue;
+ // See if there's already an edge we can add onto
+ Vertex::EdgeMap::iterator edge_it =
+ (*graph)[blocks[i].writer].out_edges.find(blocks[i].reader);
+ if (edge_it == (*graph)[blocks[i].writer].out_edges.end()) {
+ // No existing edge. Create one
+ (*graph)[blocks[i].writer].out_edges.insert(
+ make_pair(blocks[i].reader, EdgeProperties()));
+ edge_it = (*graph)[blocks[i].writer].out_edges.find(blocks[i].reader);
+ CHECK_NE(edge_it, (*graph)[blocks[i].writer].out_edges.end());
+ }
+ graph_utils::AppendBlockToExtents(&edge_it->second.extents, i);
+ }
+}
+
+bool DeltaDiffGenerator::ReorderDataBlobs(
+ DeltaArchiveManifest* manifest,
+ const std::string& data_blobs_path,
+ const std::string& new_data_blobs_path) {
+ int in_fd = open(data_blobs_path.c_str(), O_RDONLY, 0);
+ TEST_AND_RETURN_FALSE_ERRNO(in_fd >= 0);
+ ScopedFdCloser in_fd_closer(&in_fd);
+
+ DirectFileWriter writer;
+ TEST_AND_RETURN_FALSE(
+ writer.Open(new_data_blobs_path.c_str(),
+ O_WRONLY | O_TRUNC | O_CREAT,
+ 0644) == 0);
+ ScopedFileWriterCloser writer_closer(&writer);
+ uint64 out_file_size = 0;
+
+ for (int i = 0; i < manifest->install_operations_size(); i++) {
+ DeltaArchiveManifest_InstallOperation* op =
+ manifest->mutable_install_operations(i);
+ if (!op->has_data_offset())
+ continue;
+ CHECK(op->has_data_length());
+ vector<char> buf(op->data_length());
+ ssize_t rc = pread(in_fd, &buf[0], buf.size(), op->data_offset());
+ TEST_AND_RETURN_FALSE(rc == static_cast<ssize_t>(buf.size()));
+
+ op->set_data_offset(out_file_size);
+ TEST_AND_RETURN_FALSE(writer.Write(&buf[0], buf.size()) ==
+ static_cast<ssize_t>(buf.size()));
+ out_file_size += buf.size();
+ }
+ return true;
+}
+
+bool DeltaDiffGenerator::GenerateDeltaUpdateFile(const string& old_root,
+ const string& old_image,
+ const string& new_root,
+ const string& new_image,
+ const string& output_path) {
+ struct stat old_image_stbuf;
+ TEST_AND_RETURN_FALSE_ERRNO(stat(old_image.c_str(), &old_image_stbuf) == 0);
+ struct stat new_image_stbuf;
+ TEST_AND_RETURN_FALSE_ERRNO(stat(new_image.c_str(), &new_image_stbuf) == 0);
+ LOG_IF(WARNING, new_image_stbuf.st_size != old_image_stbuf.st_size)
+ << "Old and new images are different sizes.";
+ LOG_IF(FATAL, new_image_stbuf.st_size % kBlockSize)
+ << "New image not a multiple of block size " << kBlockSize;
+ LOG_IF(FATAL, old_image_stbuf.st_size % kBlockSize)
+ << "Old image not a multiple of block size " << kBlockSize;
+
+ vector<Block> blocks(min(old_image_stbuf.st_size / kBlockSize,
+ new_image_stbuf.st_size / kBlockSize));
+ LOG(INFO) << "blocks (orig): " << (uint32)(&blocks);
+ LOG(INFO) << "w:" << blocks[4097].writer;
+ LOG(INFO) << "invalid: " << Vertex::kInvalidIndex;
+ LOG(INFO) << "len: " << blocks.size();
+ for (vector<Block>::size_type i = 0; i < blocks.size(); i++) {
+ CHECK(blocks[i].reader == Vertex::kInvalidIndex);
+ CHECK(blocks[i].writer == Vertex::kInvalidIndex);
+ }
+ Graph graph;
+ CheckGraph(graph);
+
+ const string kTempFileTemplate("/tmp/CrAU_temp_data.XXXXXX");
+ string temp_file_path;
+ off_t data_file_size = 0;
+
+ LOG(INFO) << "Reading files...";
+
+ DeltaArchiveManifest_InstallOperation final_op;
+ {
+ int fd;
+ TEST_AND_RETURN_FALSE(
+ utils::MakeTempFile(kTempFileTemplate, &temp_file_path, &fd));
+ TEST_AND_RETURN_FALSE(fd >= 0);
+ ScopedFdCloser fd_closer(&fd);
+
+ TEST_AND_RETURN_FALSE(DeltaReadFiles(&graph,
+ &blocks,
+ old_root,
+ new_root,
+ fd,
+ &data_file_size));
+ CheckGraph(graph);
+
+ // TODO(adlr): read all the rest of the blocks in
+ TEST_AND_RETURN_FALSE(ReadUnwrittenBlocks(blocks,
+ fd,
+ &data_file_size,
+ new_image,
+ &final_op));
+ }
+ CheckGraph(graph);
+
+ LOG(INFO) << "Creating edges...";
+ CreateEdges(&graph, blocks);
+ CheckGraph(graph);
+
+ CycleBreaker cycle_breaker;
+ LOG(INFO) << "Finding cycles...";
+ set<Edge> cut_edges;
+ cycle_breaker.BreakCycles(graph, &cut_edges);
+ CheckGraph(graph);
+
+ // Calculate number of scratch blocks needed
+
+ LOG(INFO) << "Cutting cycles...";
+ TEST_AND_RETURN_FALSE(CutEdges(&graph, blocks, cut_edges));
+ CheckGraph(graph);
+
+ vector<Vertex::Index> final_order;
+ LOG(INFO) << "Ordering...";
+ TopologicalSort(graph, &final_order);
+ CheckGraph(graph);
+
+ // Convert to protobuf Manifest object
+ DeltaArchiveManifest manifest;
+ CheckGraph(graph);
+ InstallOperationsToManifest(graph, final_order, &manifest);
+ {
+ // Write final operation
+ DeltaArchiveManifest_InstallOperation* op =
+ manifest.add_install_operations();
+ *op = final_op;
+ CHECK(op->has_type());
+ LOG(INFO) << "final op length: " << op->data_length();
+ }
+ CheckGraph(graph);
+ manifest.set_block_size(kBlockSize);
+ // TODO(adlr): set checksums
+
+ // Reorder the data blobs with the newly ordered manifest
+ string ordered_blobs_path;
+ TEST_AND_RETURN_FALSE(utils::MakeTempFile(
+ "/tmp/CrAU_temp_data.ordered.XXXXXX",
+ &ordered_blobs_path,
+ false));
+ TEST_AND_RETURN_FALSE(ReorderDataBlobs(&manifest,
+ temp_file_path,
+ ordered_blobs_path));
+
+ // Check that install op blobs are in order and that all blocks are written.
+ {
+ vector<uint32> written_count(blocks.size(), 0);
+ uint64 next_blob_offset = 0;
+ for (int i = 0; i < manifest.install_operations_size(); i++) {
+ const DeltaArchiveManifest_InstallOperation& op =
+ manifest.install_operations(i);
+ for (int j = 0; j < op.dst_extents_size(); j++) {
+ const Extent& extent = op.dst_extents(j);
+ for (uint64 block = extent.start_block();
+ block < (extent.start_block() + extent.num_blocks()); block++) {
+ written_count[block]++;
+ }
+ }
+ if (op.has_data_offset()) {
+ if (op.data_offset() != next_blob_offset) {
+ LOG(FATAL) << "bad blob offset! " << op.data_offset() << " != "
+ << next_blob_offset;
+ }
+ next_blob_offset += op.data_length();
+ }
+ }
+ // check all blocks written to
+ for (vector<uint32>::size_type i = 0; i < written_count.size(); i++) {
+ if (written_count[i] == 0) {
+ LOG(FATAL) << "block " << i << " not written!";
+ }
+ }
+ }
+
+ // Serialize protobuf
+ string serialized_manifest;
+
+ CheckGraph(graph);
+ TEST_AND_RETURN_FALSE(manifest.AppendToString(&serialized_manifest));
+ CheckGraph(graph);
+
+ LOG(INFO) << "Writing final delta file header...";
+ DirectFileWriter writer;
+ TEST_AND_RETURN_FALSE_ERRNO(writer.Open(output_path.c_str(),
+ O_WRONLY | O_CREAT | O_TRUNC,
+ 0644) == 0);
+ ScopedFileWriterCloser writer_closer(&writer);
+
+ // Write header
+ TEST_AND_RETURN_FALSE(writer.Write(kDeltaMagic, strlen(kDeltaMagic)) ==
+ strlen(kDeltaMagic));
+
+ // Write version number
+ TEST_AND_RETURN_FALSE(WriteUint64AsBigEndian(&writer, kVersionNumber));
+
+ // Write protobuf length
+ TEST_AND_RETURN_FALSE(WriteUint64AsBigEndian(&writer,
+ serialized_manifest.size()));
+
+ // Write protobuf
+ LOG(INFO) << "Writing final delta file protobuf... "
+ << serialized_manifest.size();
+ TEST_AND_RETURN_FALSE(writer.Write(serialized_manifest.data(),
+ serialized_manifest.size()) ==
+ static_cast<ssize_t>(serialized_manifest.size()));
+
+ // Append the data blobs
+ LOG(INFO) << "Writing final delta file data blobs...";
+ int blobs_fd = open(temp_file_path.c_str(), O_RDONLY, 0);
+ ScopedFdCloser blobs_fd_closer(&blobs_fd);
+ TEST_AND_RETURN_FALSE(blobs_fd >= 0);
+ for (;;) {
+ char buf[kBlockSize];
+ ssize_t rc = read(blobs_fd, buf, sizeof(buf));
+ if (0 == rc) {
+ // EOF
+ break;
+ }
+ TEST_AND_RETURN_FALSE_ERRNO(rc > 0);
+ TEST_AND_RETURN_FALSE(writer.Write(buf, rc) == rc);
+ }
+
+ LOG(INFO) << "All done. Successfully created delta file.";
+ return true;
+}
+
+}; // namespace chromeos_update_engine