// Copyright 2014 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 TRUNKS_TPM_UTILITY_H_
#define TRUNKS_TPM_UTILITY_H_

#include <string>

#include <base/macros.h>
#include <chromeos/chromeos_export.h>

#include "trunks/tpm_generated.h"

namespace trunks {

// These handles will be used by TpmUtility to create storage root keys.
const TPMI_DH_PERSISTENT kRSAStorageRootKey = PERSISTENT_FIRST;
const TPMI_DH_PERSISTENT kECCStorageRootKey = PERSISTENT_FIRST + 1;

// An interface which provides convenient methods for common TPM operations.
class CHROMEOS_EXPORT TpmUtility {
 public:
  TpmUtility() {}
  virtual ~TpmUtility() {}

  // Synchronously performs a TPM startup sequence and self tests. Typically
  // this is done by the platform firmware. Returns the result of the startup
  // and self-tests or, if already started, just the result of the self-tests.
  virtual TPM_RC Startup() = 0;

  // Synchronously prepares a TPM for use by Chromium OS. Typically this is done
  // by the platform firmware and, in that case, this method has no effect.
  virtual TPM_RC InitializeTpm() = 0;

  // Stir the tpm random generation module with some random entropy data.
  virtual TPM_RC StirRandom(const std::string& entropy_data) = 0;

  // This method returns |num_bytes| of random data generated by the tpm.
  virtual TPM_RC GenerateRandom(int num_bytes, std::string* random_data) = 0;

  // This method extends the pcr specified by |pcr_index| with the SHA256
  // hash of |extend_data|. The exact action performed is
  // TPM2_PCR_Extend(Sha256(extend_data));
  virtual TPM_RC ExtendPCR(int pcr_index, const std::string& extend_data) = 0;

  // This method reads the pcr specified by |pcr_index| and returns its value
  // in |pcr_value|. NOTE: it assumes we are using SHA256 as our hash alg.
  virtual TPM_RC ReadPCR(int pcr_index, std::string* pcr_value) = 0;

  // Synchronously takes ownership of the TPM with the given passwords as
  // authorization values.
  virtual TPM_RC TakeOwnership(const std::string& owner_password,
                               const std::string& endorsement_password,
                               const std::string& lockout_password) = 0;

  // Synchronously derives storage root keys for RSA and ECC and persists the
  // keys in the TPM. This operation must be authorized by the |owner_password|
  // and, on success, KRSAStorageRootKey and kECCStorageRootKey can be used
  // with an empty authorization value until the TPM is cleared.
  virtual TPM_RC CreateStorageRootKeys(const std::string& owner_password) = 0;

 private:
  DISALLOW_COPY_AND_ASSIGN(TpmUtility);
};

}  // namespace trunks

#endif  // TRUNKS_TPM_UTILITY_H_