From a3a9f25e028da2cb6b366c91c24af564dcd6c27c Mon Sep 17 00:00:00 2001
From: Sebastian Messmer <messmer@cryfs.org>
Date: Mon, 21 Jan 2019 22:25:58 -0800
Subject: [PATCH] Make integrity migration interrupt-safe

---
 .../integrity/IntegrityBlockStore2.cpp          | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/blockstore/implementations/integrity/IntegrityBlockStore2.cpp b/src/blockstore/implementations/integrity/IntegrityBlockStore2.cpp
index 62ae8f43..1b37b97b 100644
--- a/src/blockstore/implementations/integrity/IntegrityBlockStore2.cpp
+++ b/src/blockstore/implementations/integrity/IntegrityBlockStore2.cpp
@@ -2,11 +2,13 @@
 #include "IntegrityBlockStore2.h"
 #include "KnownBlockVersions.h"
 #include <cpp-utils/data/SerializationHelper.h>
+#include <cpp-utils/process/SignalCatcher.h>
 
 using cpputils::Data;
 using cpputils::unique_ref;
 using cpputils::serialize;
 using cpputils::deserialize;
+using cpputils::SignalCatcher;
 using std::string;
 using boost::optional;
 using boost::none;
@@ -195,22 +197,31 @@ void IntegrityBlockStore2::forEachBlock(std::function<void (const BlockId &)> ca
 
 #ifndef CRYFS_NO_COMPATIBILITY
 void IntegrityBlockStore2::migrateFromBlockstoreWithoutVersionNumbers(BlockStore2 *baseBlockStore, const boost::filesystem::path &integrityFilePath, uint32_t myClientId) {
+  SignalCatcher signalCatcher;
+
   std::cout << "Migrating file system for integrity features. Please don't interrupt this process. This can take a while..." << std::flush;
   KnownBlockVersions knownBlockVersions(integrityFilePath, myClientId);
-  baseBlockStore->forEachBlock([&baseBlockStore, &knownBlockVersions] (const BlockId &blockId) {
+  baseBlockStore->forEachBlock([&baseBlockStore, &knownBlockVersions, &signalCatcher] (const BlockId &blockId) {
+    if (signalCatcher.signal_occurred()) {
+      throw std::runtime_error("Caught signal");
+    }
     migrateBlockFromBlockstoreWithoutVersionNumbers(baseBlockStore, blockId, &knownBlockVersions);
   });
   std::cout << "done" << std::endl;
 }
 
 void IntegrityBlockStore2::migrateBlockFromBlockstoreWithoutVersionNumbers(blockstore::BlockStore2* baseBlockStore, const blockstore::BlockId& blockId, KnownBlockVersions *knownBlockVersions) {
-  uint64_t version = knownBlockVersions->incrementVersion(blockId);
-
   auto data_ = baseBlockStore->load(blockId);
   if (data_ == boost::none) {
     LOG(WARN, "Block not found, but was returned from forEachBlock before");
     return;
   }
+  if (0 != _readFormatHeader(*data_)) {
+      // already migrated
+      return;
+  }
+
+  uint64_t version = knownBlockVersions->incrementVersion(blockId);
   cpputils::Data data = std::move(*data_);
   cpputils::Data dataWithHeader = _prependHeaderToData(blockId, knownBlockVersions->myClientId(), version, data);
   baseBlockStore->store(blockId, dataWithHeader);