/** @file
  Copyright (C) 2019, vit9696. All rights reserved.

  All rights reserved.

  This program and the accompanying materials
  are licensed and made available under the terms and conditions of the BSD License
  which accompanies this distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/

#ifndef OC_STORAGE_LIB_H
#define OC_STORAGE_LIB_H

#include <Library/OcCryptoLib.h>
#include <Library/OcGuardLib.h>
#include <Library/OcFileLib.h>
#include <Library/OcSerializeLib.h>

/**
  Storage vault file containing a dictionary with SHA-256 hashes for all files.
**/
#define OC_STORAGE_VAULT_PATH L"vault.plist"

/**
  RSA-2048 signature of SHA-256 hash of vault.plist.
**/
#define OC_STORAGE_VAULT_SIGNATURE_PATH L"vault.sig"

/**
  Storage vault version declaring vault compatibility.
**/
#define OC_STORAGE_VAULT_VERSION 1

/**
  Safe maximum file path in the storage.
**/
#define OC_STORAGE_SAFE_PATH_MAX 128

/**
  Structure declaration for valult file.
**/
#define OC_STORAGE_VAULT_HASH_FIELDS(_, __) \
  _(UINT8      , Hash     , [SHA256_DIGEST_SIZE] , {0}         , () )
  OC_DECLARE (OC_STORAGE_VAULT_HASH)

#define OC_STORAGE_VAULT_FILES_FIELDS(_, __) \
  OC_MAP (OC_STRING, OC_STORAGE_VAULT_HASH, _, __)
  OC_DECLARE (OC_STORAGE_VAULT_FILES)

#define OC_STORAGE_VAULT_FIELDS(_, __) \
  _(UINT32                      , Version  ,     , 0                                         , () ) \
  _(OC_STORAGE_VAULT_FILES      , Files    ,     , OC_CONSTR (OC_STORAGE_VAULT_FILES, _, __) , OC_DESTR (OC_STORAGE_VAULT_FILES))
  OC_DECLARE (OC_STORAGE_VAULT)

/**
  Storage abstraction context
**/
typedef struct {
  ///
  /// Storage file system if any.
  ///
  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL  *FileSystem;
  ///
  /// Storage root owned by context.
  ///
  EFI_FILE_PROTOCOL                *StorageRoot;
  ///
  /// Device handle with storage (dummy) device path for loading.
  ///
  EFI_HANDLE                       StorageHandle;
  ///
  /// Dummy file path for file storage.
  ///
  EFI_DEVICE_PATH_PROTOCOL         *DummyDevicePath;
  ///
  /// Dummy file path relative to storage.
  ///
  EFI_DEVICE_PATH_PROTOCOL         *DummyFilePath;
  ///
  /// Vault context.
  ///
  OC_STORAGE_VAULT                 Vault;
  ///
  /// Vault status.
  ///
  BOOLEAN                          HasVault;
} OC_STORAGE_CONTEXT;

/**
  Create storage context from UEFI file system at specified path.

  @param[out]  Context     Resulting storage context.
  @param[in]   FileSystem  Storage file system.
  @param[in]   Path        Storage file system path (e.g. L"\\").
  @param[in]   StorageKey         Storage signature verification key, optional.

  @retval EFI_SUCCESS on success.
**/
EFI_STATUS
OcStorageInitFromFs (
  OUT OC_STORAGE_CONTEXT               *Context,
  IN  EFI_SIMPLE_FILE_SYSTEM_PROTOCOL  *FileSystem,
  IN  CONST CHAR16                     *Path,
  IN  OC_RSA_PUBLIC_KEY                *StorageKey OPTIONAL
  );

/**
  Free storage context resources.

  @param[in,out]  Context     Storage context.
**/
VOID
OcStorageFree (
  IN OUT OC_STORAGE_CONTEXT            *Context
  );

/**
  Check whether file exists.

  @param[in]  Context      Storage context.
  @param[in]  FilePath     The full path to the file on the device.

  @retval TRUE if file is present in vault or ondisk.
**/
BOOLEAN
OcStorageExistsFileUnicode (
  IN  OC_STORAGE_CONTEXT               *Context,
  IN  CONST CHAR16                     *FilePath
  );

/**
  Read file from storage with implicit double (2 byte) null termination.
  Null termination does not affect the returned file size.
  Depending on the implementation 0 byte files may return null.
  If storage context was created with valid storage key, then signature
  checking will be performed

  @param[in]  Context      Storage context.
  @param[in]  FilePath     The full path to the file on the device.
  @param[out] FileSize     The size of the file read (optional).

  @retval A pointer to a buffer containing file read or NULL.
**/
VOID *
OcStorageReadFileUnicode (
  IN  OC_STORAGE_CONTEXT               *Context,
  IN  CONST CHAR16                     *FilePath,
  OUT UINT32                           *FileSize OPTIONAL
  );

#endif // OC_STORAGE_LIB_H