// Copyright 2017 The BoringSSL Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef OPENSSL_HEADER_CRYPTO_FIPSMODULE_DELOCATE_H
#define OPENSSL_HEADER_CRYPTO_FIPSMODULE_DELOCATE_H

#include <openssl/base.h>

#include "../internal.h"


#if defined(BORINGSSL_PREFIX)
#define BCM_ADD_PREFIX(name) BORINGSSL_ADD_PREFIX(bcm_##name)
#else
#define BCM_ADD_PREFIX(name) bcm_##name
#endif

#if !defined(BORINGSSL_SHARED_LIBRARY) && defined(BORINGSSL_FIPS) && \
    !defined(OPENSSL_ASAN) && !defined(OPENSSL_MSAN)
#define DEFINE_BSS_GET(type, name, init_expr)                                  \
  /* delocate needs C linkage and for |name| to be unique across BCM. */       \
  extern "C" {                                                                 \
  extern type BCM_ADD_PREFIX(name);                                            \
  type BCM_ADD_PREFIX(name) init_expr;                                         \
  type *BCM_ADD_PREFIX(name##_bss_get)() __attribute__((const));               \
  } /* extern "C" */                                                           \
                                                                               \
  /* The getter functions are exported, but static variables are usually named \
   * with short names. Define a static wrapper function so the caller can use  \
   * a short name, while the symbol itself is prefixed. */                     \
  static type *name##_bss_get() { return BCM_ADD_PREFIX(name##_bss_get)(); }
#else
#define DEFINE_BSS_GET(type, name, init_expr) \
  static type name init_expr;                 \
  static type *name##_bss_get() { return &name; }
#endif

// For FIPS builds we require each of these objects be all zero.
#define DEFINE_STATIC_ONCE(name) \
  DEFINE_BSS_GET(bssl::CRYPTO_once_t, name, = CRYPTO_ONCE_INIT)
#define DEFINE_STATIC_MUTEX(name) \
  DEFINE_BSS_GET(bssl::StaticMutex, name, /* default ctor */)
#define DEFINE_STATIC_EX_DATA_CLASS(name) \
  DEFINE_BSS_GET(bssl::ExDataClass, name, /* default ctor */)

#define DEFINE_DATA(type, name, accessor_decorations)                     \
  DEFINE_BSS_GET(type, name##_storage, {})                                \
  DEFINE_STATIC_ONCE(name##_once)                                         \
  static void name##_do_init(type *out);                                  \
  static void name##_init() { name##_do_init(name##_storage_bss_get()); } \
  accessor_decorations type *name() {                                     \
    bssl::CRYPTO_once(name##_once_bss_get(), name##_init);                \
    /* See http://c-faq.com/ansi/constmismatch.html for why the following \
     * cast is needed. */                                                 \
    return (const type *)name##_storage_bss_get();                        \
  }                                                                       \
  static void name##_do_init(type *out)

// DEFINE_METHOD_FUNCTION defines a function named |name| which returns a
// method table of type const |type|*. In FIPS mode, to avoid rel.ro data, it
// is split into a CRYPTO_once_t-guarded initializer in the module and
// unhashed, non-module accessor functions to space reserved in the BSS. The
// method table is initialized by a caller-supplied function which takes a
// parameter named |out| of type |type|*. The caller should follow the macro
// invocation with the body of this function:
//
//     DEFINE_METHOD_FUNCTION(EVP_MD, EVP_md4) {
//       out->type = NID_md4;
//       out->md_size = MD4_DIGEST_LENGTH;
//       out->flags = 0;
//       out->init = md4_init;
//       out->update = md4_update;
//       out->final = md4_final;
//       out->block_size = 64;
//       out->ctx_size = sizeof(MD4_CTX);
//     }
//
// This mechanism does not use a static initializer because their execution
// order is undefined. See FIPS.md for more details.
#define DEFINE_METHOD_FUNCTION(type, name) DEFINE_DATA(type, name, const)

#define DEFINE_LOCAL_DATA(type, name) DEFINE_DATA(type, name, static const)

#endif  // OPENSSL_HEADER_CRYPTO_FIPSMODULE_DELOCATE_H