From a5391a854db186e1d5a498bd281b0fa07cde2d9f Mon Sep 17 00:00:00 2001
From: Sebastian Messmer <messmer@cryfs.org>
Date: Tue, 21 Jun 2016 16:29:56 -0700
Subject: [PATCH] Use VersionCountingBlockStore

---
 src/cpp-utils/CMakeLists.txt       |  1 +
 src/cpp-utils/system/homedir.cpp   | 25 ++++++++++++++++++++++++
 src/cpp-utils/system/homedir.h     | 15 +++++++++++++++
 src/cryfs/filesystem/CryDevice.cpp | 31 +++++++++++++++++++++++++++---
 src/cryfs/filesystem/CryDevice.h   |  3 +++
 5 files changed, 72 insertions(+), 3 deletions(-)
 create mode 100644 src/cpp-utils/system/homedir.cpp
 create mode 100644 src/cpp-utils/system/homedir.h

diff --git a/src/cpp-utils/CMakeLists.txt b/src/cpp-utils/CMakeLists.txt
index 7eb3da79..ce4b384e 100644
--- a/src/cpp-utils/CMakeLists.txt
+++ b/src/cpp-utils/CMakeLists.txt
@@ -32,6 +32,7 @@ set(SOURCES
         assert/backtrace.cpp
         assert/AssertFailed.cpp
         system/get_total_memory.cpp
+        system/homedir.cpp
 )
 
 add_library(${PROJECT_NAME} STATIC ${SOURCES})
diff --git a/src/cpp-utils/system/homedir.cpp b/src/cpp-utils/system/homedir.cpp
new file mode 100644
index 00000000..9e07463a
--- /dev/null
+++ b/src/cpp-utils/system/homedir.cpp
@@ -0,0 +1,25 @@
+#include "homedir.h"
+#include <sys/types.h>
+#include <pwd.h>
+
+namespace bf = boost::filesystem;
+using std::string;
+
+namespace cpputils {
+    namespace system {
+        bf::path home_directory() {
+            struct passwd* pwd = getpwuid(getuid());
+            string homedir;
+            if (pwd) {
+                homedir = pwd->pw_dir;
+            } else {
+                // try the $HOME environment variable
+                homedir = getenv("HOME");
+            }
+            if (homedir == "") {
+                throw std::runtime_error("Couldn't determine home directory for user");
+            }
+            return homedir;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/cpp-utils/system/homedir.h b/src/cpp-utils/system/homedir.h
new file mode 100644
index 00000000..3c8888c8
--- /dev/null
+++ b/src/cpp-utils/system/homedir.h
@@ -0,0 +1,15 @@
+#pragma once
+#ifndef MESSMER_CPPUTILS_SYSTEM_GETTOTALMEMORY_H
+#define MESSMER_CPPUTILS_SYSTEM_GETTOTALMEMORY_H
+
+#include <boost/filesystem/path.hpp>
+
+namespace cpputils {
+    namespace system {
+
+        boost::filesystem::path home_directory();
+
+    }
+}
+
+#endif
diff --git a/src/cryfs/filesystem/CryDevice.cpp b/src/cryfs/filesystem/CryDevice.cpp
index 743f279d..20d0ab15 100644
--- a/src/cryfs/filesystem/CryDevice.cpp
+++ b/src/cryfs/filesystem/CryDevice.cpp
@@ -11,9 +11,11 @@
 #include <blobstore/implementations/onblocks/BlobStoreOnBlocks.h>
 #include <blobstore/implementations/onblocks/BlobOnBlocks.h>
 #include <blockstore/implementations/encrypted/EncryptedBlockStore.h>
+#include <blockstore/implementations/versioncounting/VersionCountingBlockStore.h>
 #include "parallelaccessfsblobstore/ParallelAccessFsBlobStore.h"
 #include "cachingfsblobstore/CachingFsBlobStore.h"
 #include "../config/CryCipher.h"
+#include <cpp-utils/system/homedir.h>
 
 using std::string;
 
@@ -27,6 +29,7 @@ using blockstore::encrypted::EncryptedBlockStore;
 using blobstore::onblocks::BlobStoreOnBlocks;
 using blobstore::onblocks::BlobOnBlocks;
 using blockstore::caching::CachingBlockStore;
+using blockstore::versioncounting::VersionCountingBlockStore;
 using cpputils::unique_ref;
 using cpputils::make_unique_ref;
 using cpputils::dynamic_pointer_move;
@@ -52,10 +55,16 @@ CryDevice::CryDevice(CryConfigFile configFile, unique_ref<BlockStore> blockStore
           make_unique_ref<FsBlobStore>(
             make_unique_ref<BlobStoreOnBlocks>(
               make_unique_ref<CachingBlockStore>(
-                CreateEncryptedBlockStore(*configFile.config(), std::move(blockStore))
-              ), configFile.config()->BlocksizeBytes())))
+                make_unique_ref<VersionCountingBlockStore>(
+                  CreateEncryptedBlockStore(*configFile.config(), std::move(blockStore)),
+                  _integrityFilePath(configFile.config()->FilesystemId())
+                )
+              )
+            , configFile.config()->BlocksizeBytes())
+          )
         )
-      ),
+      )
+    ),
   _rootKey(GetOrCreateRootKey(&configFile)),
   _onFsAction() {
 }
@@ -66,6 +75,22 @@ Key CryDevice::CreateRootBlobAndReturnKey() {
   return rootBlob->key();
 }
 
+bf::path CryDevice::_integrityFilePath(const CryConfig::FilesystemID &filesystemId) {
+  bf::path app_dir = cpputils::system::home_directory() / ".cryfs";
+  _createDirIfNotExists(app_dir);
+  bf::path filesystems_dir = app_dir / "filesystems";
+  _createDirIfNotExists(filesystems_dir);
+  bf::path this_filesystem_dir = filesystems_dir / filesystemId.ToString();
+  _createDirIfNotExists(this_filesystem_dir);
+  return this_filesystem_dir / "integritydata.knownblockversions";
+}
+
+void CryDevice::_createDirIfNotExists(const bf::path &path) {
+  if (!bf::exists(path)) {
+    bf::create_directory(path);
+  }
+}
+
 optional<unique_ref<fspp::Node>> CryDevice::Load(const bf::path &path) {
   // TODO Split into smaller functions
   ASSERT(path.is_absolute(), "Non absolute path given");
diff --git a/src/cryfs/filesystem/CryDevice.h b/src/cryfs/filesystem/CryDevice.h
index 6848b481..3a595b8d 100644
--- a/src/cryfs/filesystem/CryDevice.h
+++ b/src/cryfs/filesystem/CryDevice.h
@@ -47,6 +47,9 @@ private:
   blockstore::Key _rootKey;
   std::vector<std::function<void()>> _onFsAction;
 
+  static boost::filesystem::path _integrityFilePath(const CryConfig::FilesystemID &filesystemId);
+  static void _createDirIfNotExists(const boost::filesystem::path &path);
+
   blockstore::Key GetOrCreateRootKey(CryConfigFile *config);
   blockstore::Key CreateRootBlobAndReturnKey();
   static cpputils::unique_ref<blockstore::BlockStore> CreateEncryptedBlockStore(const CryConfig &config, cpputils::unique_ref<blockstore::BlockStore> baseBlockStore);