From bf74e4e0524dc0c525340aad3c688e6bf8dadf43 Mon Sep 17 00:00:00 2001
From: Adrian Szyndela <adrian.s@samsung.com>
Date: Tue, 3 Nov 2020 10:42:17 +0100
Subject: [PATCH] serialization: add simple file verification method

Change-Id: I95d3501bcfffa0e4601ee2c3738b38c41b366a44
---
 src/internal/serializer_direct.cpp      |  4 +++-
 src/internal/storage_backend_direct.cpp | 22 +++++++++++++++++++++-
 src/internal/storage_backend_direct.hpp |  7 +++++++
 3 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/src/internal/serializer_direct.cpp b/src/internal/serializer_direct.cpp
index d74ce9b..d90387e 100644
--- a/src/internal/serializer_direct.cpp
+++ b/src/internal/serializer_direct.cpp
@@ -24,6 +24,7 @@
 #include "serialization_traits.hpp"
 #include "serialized.hpp"
 #include "serializer_direct.hpp"
+#include "storage_backend_direct.hpp"
 
 using namespace ldp_serializer;
 using ldp_serializer::Serialized;
@@ -154,7 +155,8 @@ const uint8_t *SerializerDirectImpl::serialize(size_t &size) {
 		serializeSet<ldp_xml_parser::PolicyOwn>(),
 		serializeSet<ldp_xml_parser::PolicySend>(),
 		serializeSet<ldp_xml_parser::PolicyReceive>(),
-		serializeSet<ldp_xml_parser::PolicyAccess>()};
+		serializeSet<ldp_xml_parser::PolicyAccess>(),
+		ldp_serialized::StorageBackendDirect::currentDbVersion};
 
 	size = r.size();
 	return r.releaseData();
diff --git a/src/internal/storage_backend_direct.cpp b/src/internal/storage_backend_direct.cpp
index 455f443..5628b52 100644
--- a/src/internal/storage_backend_direct.cpp
+++ b/src/internal/storage_backend_direct.cpp
@@ -20,12 +20,32 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE. */
 
+#include "tslog.hpp"
 #include "storage_backend_direct.hpp"
+#include <cassert>
 
 using namespace ldp_serialized;
 
-bool StorageBackendDirect::initFromData(const uint8_t *mem, size_t , bool ) {
+const boost::string_ref StorageBackendDirect::currentDbVersion{"Libdbuspolicy direct serialization database, v. 1.0"};
 
+bool StorageBackendDirect::initFromData(const uint8_t *mem, size_t size, bool verify) {
+	assert(mem);
 	file = reinterpret_cast<const File*>(mem);
+
+	if (verify) {
+		bool verified = false;
+		auto end = mem + size;
+		auto version = fileGetDbVersion(file);
+		auto version_uint8 = reinterpret_cast<const uint8_t *>(version);
+		if (version_uint8 < end) {
+			auto s = stringGetSize(version);
+			if (version_uint8 + s < end)
+				verified = currentDbVersion == stringGetCStr(version);
+		}
+
+		if (!verified)
+			file = nullptr;
+	}
+
 	return file != nullptr;
 }
diff --git a/src/internal/storage_backend_direct.hpp b/src/internal/storage_backend_direct.hpp
index 4b3b47b..7afb1f7 100644
--- a/src/internal/storage_backend_direct.hpp
+++ b/src/internal/storage_backend_direct.hpp
@@ -122,6 +122,7 @@ namespace ldp_serialized {
  * 			}
  * 		}
  * 	}
+ *  db_version: string;
  *
  * 	define DecisionItem = {
  * 		decision: Decision;
@@ -371,6 +372,8 @@ public:
 	{ return ptr<ReceiveSetType>(2); }
 	const auto *getAccessSet() const
 	{ return ptr<AccessSetType>(3); }
+	const auto *getDbVersion() const
+	{ return ptr<Str>(4); }
 };
 
 class StorageBackendDirect {
@@ -398,6 +401,8 @@ class StorageBackendDirect {
 		return std::make_pair(false, *container->begin());
 	}
 public:
+	static const boost::string_ref currentDbVersion;
+
 	bool initFromData(const uint8_t *serialized_data, size_t size, bool verify = false);
 	void release() {}
 
@@ -412,6 +417,8 @@ public:
 	{ return file->getReceiveSet(); }
 	auto fileGetAccessSet(const File *file) const
 	{ return file->getAccessSet(); }
+	auto fileGetDbVersion(const File *file) const
+	{ return file->getDbVersion(); }
 
 	template <typename PolicyType>
 	auto setGetContextDefault(const Set<PolicyType> *set) const
-- 
2.7.4