libguard: Adding function to check write flag

Change:
Adding function checkWriteflag, which will read the
write flag.

Signed-off-by: Chirag Sharma <chirshar@in.ibm.com>

Author: Chirag Sharma

libguard/guard_interface.cpp

@@ -426,6 +426,20 @@ void invalidateAll()
     toggleWriteFlag(file);
 }
 
+bool checkWriteFlag()
+{
+    GuardFile file(guardFilePath);
+    GuardRecord_t guardRecord;
+    size_t headerPos = 9;
+    file.read(headerPos, &guardRecord.iv_flags, sizeof(guardRecord.iv_flags));
+
+    if (guardRecord.iv_flags == 0x00)
+    {
+        return true;
+    }
+    return false;
+}
+
 void libguard_init(bool enableDevtree)
 {
     initialize();

libguard/guard_interface.hpp

@@ -149,6 +149,13 @@ const fs::path& getGuardFilePath();
  */
 bool isEphemeralType(const uint8_t recordType);
 
+/**
+ * @brief Used to read the write flag of guard header
+ *
+ * @return true if bit is set else false.
+ */
+bool checkWriteFlag();
+
 namespace utest
 {
 void setGuardFile(const fs::path& file);