Fix for restoreFromFile cereal exception

This commit provides a fix for an issue in which the cereal
restoreFromFile() would crash the host software updater in the event
that a priority persistence file is empty.

Resolves openbmc/openbmc#2091

Change-Id: Icca5d68ef250e2662cd02075c6ba731e4ab768b0
Signed-off-by: Michael Tritz <mtritz@us.ibm.com>

1 files changed, 12 insertions, 3 deletions

diff --git a/serialize.cpp b/serialize.cpp
index 8e957272b..a499798c4 100644
--- a/serialize.cpp
+++ b/serialize.cpp
@@ -26,15 +26,24 @@ void storeToFile(std::string versionId, uint8_t priority)
     oarchive(cereal::make_nvp("priority", priority));
 }
 
-void restoreFromFile(std::string versionId, uint8_t *priority)
+bool restoreFromFile(std::string versionId, uint8_t& priority)
 {
     std::string path = PERSIST_DIR + versionId;
     if (fs::exists(path))
     {
         std::ifstream is(path.c_str(), std::ios::in);
-        cereal::JSONInputArchive iarchive(is);
-        iarchive(cereal::make_nvp("priority", *priority));
+        try
+        {
+            cereal::JSONInputArchive iarchive(is);
+            iarchive(cereal::make_nvp("priority", priority));
+            return true;
+        }
+        catch(cereal::RapidJSONException& e)
+        {
+            fs::remove(path);
+        }
     }
+    return false;
 }
 
 void removeFile(std::string versionId)