text: /*
   * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
   *
   * Licensed under the Apache License 2.0 (the "License").  You may not use
   * this file except in compliance with the License.  You can obtain a copy
   * in the file LICENSE in the source distribution or at
   * https://www.openssl.org/source/license.html
   */
  
  /*
   * Licensed under the Apache License 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.openssl.org/source/license.html
   * or in the file LICENSE in the source distribution.
   */
  
  #ifndef HEADER_RAND_INT_H
  # define HEADER_RAND_INT_H
  
  # include <openssl/rand.h>
  
  /* forward declaration */
  typedef struct rand_pool_st RAND_POOL;
  
  void VR_rand_cleanup_int(void);
  void VR_rand_drbg_cleanup_int(void);
  void VR_drbg_delete_thread_state(void);
  void VR_rand_fork(void);
  
  /* Hardware-based seeding functions. */
  size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool);
  size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool);
  
  /* DRBG entropy callbacks. */
  size_t VR_rand_drbg_get_entropy(RAND_DRBG *drbg,
                               unsigned char **pout,
                               int entropy, size_t min_len, size_t max_len,
                               int prediction_resistance);
  void VR_rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
                                 unsigned char *out, size_t outlen);
  size_t VR_rand_drbg_get_nonce(RAND_DRBG *drbg,
                             unsigned char **pout,
                             int entropy, size_t min_len, size_t max_len);
  void VR_rand_drbg_cleanup_nonce(RAND_DRBG *drbg,
                               unsigned char *out, size_t outlen);
  
  size_t VR_rand_drbg_get_additional_data(RAND_POOL *pool, unsigned char **pout);
  
  void VR_rand_drbg_cleanup_additional_data(RAND_POOL *pool, unsigned char *out);
  
  /*
   * RAND_POOL functions
   */
  RAND_POOL *VR_rand_pool_new(int entropy_requested, size_t min_len, size_t max_len);
  RAND_POOL *VR_rand_pool_attach(const unsigned char *buffer, size_t len,
                              size_t entropy);
  void VR_rand_pool_free(RAND_POOL *pool);
  
  const unsigned char *VR_rand_pool_buffer(RAND_POOL *pool);
  unsigned char *VR_rand_pool_detach(RAND_POOL *pool);
  void VR_rand_pool_reattach(RAND_POOL *pool, unsigned char *buffer);
  
  size_t VR_rand_pool_entropy(RAND_POOL *pool);
  size_t VR_rand_pool_length(RAND_POOL *pool);
  
  size_t VR_rand_pool_entropy_available(RAND_POOL *pool);
  size_t VR_rand_pool_entropy_needed(RAND_POOL *pool);
  /* |entropy_factor| expresses how many bits of data contain 1 bit of entropy */
  size_t VR_rand_pool_bytes_needed(RAND_POOL *pool, unsigned int entropy_factor);
  size_t VR_rand_pool_bytes_remaining(RAND_POOL *pool);
  
  int VR_rand_pool_add(RAND_POOL *pool,
                    const unsigned char *buffer, size_t len, size_t entropy);
  unsigned char *VR_rand_pool_add_begin(RAND_POOL *pool, size_t len);
  int VR_rand_pool_add_end(RAND_POOL *pool, size_t len, size_t entropy);
  
  
  /*
   * Add random bytes to the pool to acquire requested amount of entropy
   *
   * This function is platform specific and tries to acquire the requested
   * amount of entropy by polling platform specific entropy sources.
   *
   * If the function succeeds in acquiring at least |entropy_requested| bits
   * of entropy, the total entropy count is returned. If it fails, it returns
   * an entropy count of 0.
   */
  size_t VR_rand_pool_acquire_entropy(RAND_POOL *pool);
  
  /*
   * Add some application specific nonce data
   *
   * This function is platform specific and adds some application specific
   * data to the nonce used for instantiating the drbg.
   *
   * This data currently consists of the process and thread id, and a high
   * resolution timestamp. The data does not include an atomic counter,
   * because that is added by the calling function VR_rand_drbg_get_nonce().
   *
   * Returns 1 on success and 0 on failure.
   */
  int VR_rand_pool_add_nonce_data(RAND_POOL *pool);
  
  
  /*
   * Add some platform specific additional data
   *
   * This function is platform specific and adds some random noise to the
   * additional data used for generating random bytes and for reseeding
   * the drbg.
   *
   * Returns 1 on success and 0 on failure.
   */
  int VR_rand_pool_add_additional_data(RAND_POOL *pool);
  
  /*
   * Initialise the random pool reseeding sources.
   *
   * Returns 1 on success and 0 on failure.
   */
  int VR_rand_pool_init(void);
  
  /*
   * Finalise the random pool reseeding sources.
   */
  void VR_rand_pool_cleanup(void);
  
  /*
   * Control the random pool use of open file descriptors.
   */
  void VR_rand_pool_keep_random_devices_open(int keep);
  
  #endif
  