chromeos: Check validity of loaded data in DriveResourceMetadataStorageDB::Initialize

Broken data should be detected and cleared during initialization to avoid fatal bugs.

BUG=232054
TEST=unit_tests

Review URL: https://codereview.chromium.org/14167009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@194550 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 133 insertions, 9 deletions

diff --git a/chrome/browser/chromeos/drive/drive_resource_metadata_storage.cc b/chrome/browser/chromeos/drive/drive_resource_metadata_storage.cc
index 17bf4e9..7546b1c 100644
--- a/chrome/browser/chromeos/drive/drive_resource_metadata_storage.cc
+++ b/chrome/browser/chromeos/drive/drive_resource_metadata_storage.cc
@@ -201,12 +201,10 @@ bool DriveResourceMetadataStorageDB::Initialize() {
   if (status.ok())
     child_map_.reset(db);
 
-  // Check the version of existing DB.
+  // Check the validity of existing DB.
   if (resource_map_ && child_map_) {
-    scoped_ptr<DriveResourceMetadataHeader> header = GetHeader();
-    if (!header ||
-        header->version() != kDBVersion) {
-      LOG(ERROR) << "Reject incompatible DB.";
+    if (!CheckValidity()) {
+      LOG(ERROR) << "Reject invalid DB.";
       resource_map_.reset();
       child_map_.reset();
     }
@@ -429,4 +427,72 @@ DriveResourceMetadataStorageDB::GetHeader() {
   return header.Pass();
 }
 
+bool DriveResourceMetadataStorageDB::CheckValidity() {
+  base::ThreadRestrictions::AssertIOAllowed();
+
+  // Perform read with checksums verification enalbed.
+  leveldb::ReadOptions options;
+  options.verify_checksums = true;
+
+  scoped_ptr<leveldb::Iterator> it(resource_map_->NewIterator(options));
+  it->SeekToFirst();
+
+  // Check the header.
+  DriveResourceMetadataHeader header;
+  if (!it->Valid() ||
+      it->key() != GetHeaderDBKey() ||  // Header entry must come first.
+      !header.ParseFromArray(it->value().data(), it->value().size()) ||
+      header.version() != kDBVersion) {
+    DLOG(ERROR) << "Invalid header detected. version = " << header.version();
+    return false;
+  }
+
+  // Check all entires.
+  size_t num_checked_child_map_entries = 0;
+  DriveEntryProto entry;
+  std::string child_resource_id;
+  for (it->Next(); it->Valid(); it->Next()) {
+    // Check if stored data is broken.
+    if (!entry.ParseFromArray(it->value().data(), it->value().size()) ||
+        entry.resource_id() != it->key()) {
+      DLOG(ERROR) << "Broken entry detected";
+      return false;
+    }
+
+    // Check if parent-child relationship is stored correctly.
+    if (!entry.parent_resource_id().empty()) {
+      leveldb::Status status = child_map_->Get(
+          options,
+          leveldb::Slice(GetChildMapKey(entry.parent_resource_id(),
+                                        entry.base_name())),
+          &child_resource_id);
+      if (!status.ok() || child_resource_id != entry.resource_id()) {
+        DLOG(ERROR) << "Child map is broken. status = " << status.ToString();
+        return false;
+      }
+      ++num_checked_child_map_entries;
+    }
+  }
+  if (!it->status().ok()) {
+    DLOG(ERROR) << "Error during checking resource map. status = "
+                << it->status().ToString();
+    return false;
+  }
+
+  // Check all child map entries are referenced from |resource_map_|.
+  size_t num_child_map_entries = 0;
+  it.reset(child_map_->NewIterator(options));
+  for (it->SeekToFirst(); it->Valid(); it->Next()) {
+    ++num_child_map_entries;
+  }
+  if (!it->status().ok() ||
+      num_child_map_entries != num_checked_child_map_entries) {
+    DLOG(ERROR) << "Error during checking child map. status = "
+                << it->status().ToString();
+    return false;
+  }
+
+  return true;
+}
+
 }  // namespace drive
diff --git a/chrome/browser/chromeos/drive/drive_resource_metadata_storage.h b/chrome/browser/chromeos/drive/drive_resource_metadata_storage.h
index fb78c4b..13da193 100644
--- a/chrome/browser/chromeos/drive/drive_resource_metadata_storage.h
+++ b/chrome/browser/chromeos/drive/drive_resource_metadata_storage.h
@@ -162,6 +162,9 @@ class DriveResourceMetadataStorageDB
   // Gets header.
   scoped_ptr<DriveResourceMetadataHeader> GetHeader();
 
+  // Checks validity of the data.
+  bool CheckValidity();
+
   // Path to the directory where the data is stored.
   base::FilePath directory_path_;
 
diff --git a/chrome/browser/chromeos/drive/drive_resource_metadata_storage_unittest.cc b/chrome/browser/chromeos/drive/drive_resource_metadata_storage_unittest.cc
index 10dfd8f..f9f7c62 100644
--- a/chrome/browser/chromeos/drive/drive_resource_metadata_storage_unittest.cc
+++ b/chrome/browser/chromeos/drive/drive_resource_metadata_storage_unittest.cc
@@ -44,6 +44,10 @@ class DriveResourceMetadataStorageTest : public testing::Test {
     storage_->PutHeader(*header);
   }
 
+  bool CheckValidity() {
+    return storage_->CheckValidity();
+  }
+
   base::ScopedTempDir temp_dir_;
   scoped_ptr<DriveResourceMetadataStorageDB> storage_;
 };
@@ -199,23 +203,32 @@ TEST_F(DriveResourceMetadataStorageTest, OpenExistingDB) {
 
   DriveEntryProto entry1;
   entry1.set_resource_id(parent_id1);
+  DriveEntryProto entry2;
+  entry2.set_resource_id(child_id1);
+  entry2.set_parent_resource_id(parent_id1);
+  entry2.set_base_name(child_name1);
 
   // Put some data.
   storage_->PutEntry(entry1);
+  storage_->PutEntry(entry2);
   storage_->PutChild(parent_id1, child_name1, child_id1);
-  scoped_ptr<DriveEntryProto> result = storage_->GetEntry(parent_id1);
-  ASSERT_TRUE(result);
-  EXPECT_EQ(parent_id1, result->resource_id());
-  EXPECT_EQ(child_id1, storage_->GetChild(parent_id1, child_name1));
 
   // Close DB and reopen.
   storage_.reset(new DriveResourceMetadataStorageDB(temp_dir_.path()));
   ASSERT_TRUE(storage_->Initialize());
 
   // Can read data.
+  scoped_ptr<DriveEntryProto> result;
   result = storage_->GetEntry(parent_id1);
   ASSERT_TRUE(result);
   EXPECT_EQ(parent_id1, result->resource_id());
+
+  result = storage_->GetEntry(child_id1);
+  ASSERT_TRUE(result);
+  EXPECT_EQ(child_id1, result->resource_id());
+  EXPECT_EQ(parent_id1, result->parent_resource_id());
+  EXPECT_EQ(child_name1, result->base_name());
+
   EXPECT_EQ(child_id1, storage_->GetChild(parent_id1, child_name1));
 }
 
@@ -251,4 +264,46 @@ TEST_F(DriveResourceMetadataStorageTest, WrongPath) {
   ASSERT_FALSE(storage_->Initialize());
 }
 
+TEST_F(DriveResourceMetadataStorageTest, CheckValidity) {
+  const std::string key1 = "foo";
+  const std::string name1 = "hoge";
+  const std::string key2 = "bar";
+  const std::string name2 = "fuga";
+  const std::string key3 = "boo";
+  const std::string name3 = "piyo";
+
+  // Put entry with key1.
+  DriveEntryProto entry;
+  entry.set_resource_id(key1);
+  entry.set_base_name(name1);
+  storage_->PutEntry(entry);
+  EXPECT_TRUE(CheckValidity());
+
+  // Put entry with key2 under key1.
+  entry.set_resource_id(key2);
+  entry.set_parent_resource_id(key1);
+  entry.set_base_name(name2);
+  storage_->PutEntry(entry);
+  EXPECT_FALSE(CheckValidity());  // Missing parent-child relationship.
+
+  // Add missing parent-child relationship between key1 and key2.
+  storage_->PutChild(key1, name2, key2);
+  EXPECT_TRUE(CheckValidity());
+
+  // Add parent-child relationship between key1 and key3.
+  storage_->PutChild(key1, name3, key3);
+  EXPECT_FALSE(CheckValidity());  // key3 is not stored in the storage.
+
+  // Put entry with key3 under key1.
+  entry.set_resource_id(key3);
+  entry.set_parent_resource_id(key1);
+  entry.set_base_name(name3);
+  storage_->PutEntry(entry);
+  EXPECT_TRUE(CheckValidity());
+
+  // Parent-child relationship with wrong name.
+  storage_->PutChild(key1, name2, key3);
+  EXPECT_FALSE(CheckValidity());
+}
+
 }  // namespace drive