AU: Verify source rootfs/kernel hashes before applying delta.

omaha_hash_calculator.h

 // Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_OMAHA_HASH_CALCULATOR_H__
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_OMAHA_HASH_CALCULATOR_H__
 
 #include <string>
 #include <vector>
 
@@ skipping 44 matching lines @@
   // data (including \0 characters).
   std::string GetContext() const;
 
   // Sets the current hash context. |context| must the string returned by a
   // previous OmahaHashCalculator::GetContext method call. Returns true on
   // success, and false otherwise.
   bool SetContext(const std::string& context);
 
   static bool RawHashOfData(const std::vector<char>& data,
                             std::vector<char>* out_hash);
+  static off_t RawHashOfFile(const std::string& name, off_t length,
+                             std::vector<char>* out_hash);
 
   // Used by tests
   static std::string OmahaHashOfBytes(const void* data, size_t length);
   static std::string OmahaHashOfString(const std::string& str);
   static std::string OmahaHashOfData(const std::vector<char>& data);
 
  private:
   // If non-empty, the final base64 encoded hash and the raw hash. Will only be
   // set to non-empty when Finalize is called.
   std::string hash_;
   std::vector<char> raw_hash_;
 
   // Init success
   bool valid_;
 
   // The hash state used by OpenSSL
   SHA256_CTX ctx_;
   DISALLOW_COPY_AND_ASSIGN(OmahaHashCalculator);
 };
 
 }  // namespace chromeos_update_engine
 
 #endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_OMAHA_HASH_CALCULATOR_H__