// Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.

//

// 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.

#include <openssl/ex_data.h>

#include <assert.h>

#include <limits.h>

#include <stdlib.h>

#include <string.h>

#include <openssl/crypto.h>

#include <openssl/err.h>

#include <openssl/mem.h>

#include "internal.h"

#include "mem_internal.h"

BSSL_NAMESPACE_BEGIN

struct ExDataFuncs {

  long argl;   // Arbitrary long

  void *argp;  // Arbitrary void pointer

  CRYPTO_EX_free *free_func;

  // next points to the next |ExDataFuncs| or NULL if this is the last

  // one. It may only be read if synchronized with a read from |num_funcs|.

  ExDataFuncs *next;

};

int CRYPTO_get_ex_new_index_ex(ExDataClass *ex_data_class, long argl,

                               void *argp, CRYPTO_EX_free *free_func) {

  ExDataFuncs *funcs = New<ExDataFuncs>();

  if (funcs == nullptr) {

    return -1;

  }

  funcs->argl = argl;

  funcs->argp = argp;

  funcs->free_func = free_func;

  funcs->next = nullptr;

  MutexWriteLock lock(&ex_data_class->lock);

  uint32_t num_funcs = ex_data_class->num_funcs.load();

  // The index must fit in |int|.

  if (num_funcs > (size_t)(INT_MAX - ex_data_class->num_reserved)) {

    OPENSSL_PUT_ERROR(CRYPTO, ERR_R_OVERFLOW);

    return -1;

  }

  // Append |funcs| to the linked list.

  if (ex_data_class->last == nullptr) {

    assert(num_funcs == 0);

    ex_data_class->funcs = funcs;

    ex_data_class->last = funcs;

  } else {

    ex_data_class->last->next = funcs;

    ex_data_class->last = funcs;

  }

  ex_data_class->num_funcs.store(num_funcs + 1);

  return (int)num_funcs + ex_data_class->num_reserved;

}

int CRYPTO_set_ex_data(CRYPTO_EX_DATA *ad, int index, void *val) {

  if (index < 0) {

    // A caller that can accidentally pass in an invalid index into this

    // function will hit an memory error if |index| happened to be valid, and

    // expected |val| to be of a different type.

    abort();

  }

  if (ad->sk == nullptr) {

    ad->sk = sk_void_new_null();

    if (ad->sk == nullptr) {

      return 0;

    }

  }

  // Add NULL values until the stack is long enough.

  for (size_t i = sk_void_num(ad->sk); i <= (size_t)index; i++) {

    if (!sk_void_push(ad->sk, nullptr)) {

      return 0;

    }

  }

  sk_void_set(ad->sk, (size_t)index, val);

  return 1;

}

void *CRYPTO_get_ex_data(const CRYPTO_EX_DATA *ad, int idx) {

  if (ad->sk == nullptr || idx < 0 || (size_t)idx >= sk_void_num(ad->sk)) {

    return nullptr;

  }

  return sk_void_value(ad->sk, idx);

}

void CRYPTO_new_ex_data(CRYPTO_EX_DATA *ad) { ad->sk = nullptr; }

void CRYPTO_free_ex_data(ExDataClass *ex_data_class, CRYPTO_EX_DATA *ad) {

  if (ad->sk == nullptr) {

    // Nothing to do.

    return;

  }

  uint32_t num_funcs = ex_data_class->num_funcs.load();

  // |CRYPTO_get_ex_new_index_ex| will not allocate indices beyond |INT_MAX|.

  assert(num_funcs <= (size_t)(INT_MAX - ex_data_class->num_reserved));

  // Defer dereferencing |ex_data_class->funcs| and |funcs->next|. It must come

  // after the |num_funcs| comparison to be correctly synchronized.

  ExDataFuncs *const *funcs = &ex_data_class->funcs;

  for (uint32_t i = 0; i < num_funcs; i++) {

    if ((*funcs)->free_func != nullptr) {

      int index = (int)i + ex_data_class->num_reserved;

      void *ptr = CRYPTO_get_ex_data(ad, index);

      (*funcs)->free_func(/*parent=*/nullptr, ptr, /*ad*/ nullptr, index,

                          (*funcs)->argl, (*funcs)->argp);

    }

    funcs = &(*funcs)->next;

  }

  sk_void_free(ad->sk);

  ad->sk = nullptr;

}

BSSL_NAMESPACE_END

void CRYPTO_cleanup_all_ex_data() {}