/*

 * Copyright 2011-2021 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

 */

#include <openssl/evp.h>

#include <openssl/rand.h>

#include "rand_local.h"

/* Implements the default OpenSSL RAND_add() method */

static int drbg_add(const void *buf, int num, double randomness)

{

    EVP_RAND_CTX *drbg = RAND_get0_primary(NULL);

    if (drbg == NULL || num <= 0)

        return 0;

    return EVP_RAND_reseed(drbg, 0, NULL, 0, buf, num);

}

/* Implements the default OpenSSL RAND_seed() method */

static int drbg_seed(const void *buf, int num)

{

    return drbg_add(buf, num, num);

}

/* Implements the default OpenSSL RAND_status() method */

static int drbg_status(void)

{

    EVP_RAND_CTX *drbg = RAND_get0_primary(NULL);

    if (drbg == NULL)

        return 0;

    return  EVP_RAND_get_state(drbg) == EVP_RAND_STATE_READY ? 1 : 0;

}

/* Implements the default OpenSSL RAND_bytes() method */

static int drbg_bytes(unsigned char *out, int count)

{

    EVP_RAND_CTX *drbg = RAND_get0_public(NULL);

    if (drbg == NULL)

        return 0;

    return EVP_RAND_generate(drbg, out, count, 0, 0, NULL, 0);

}

RAND_METHOD ossl_rand_meth = {

    drbg_seed,

    drbg_bytes,

    NULL,

    drbg_add,

    drbg_bytes,

    drbg_status

};

RAND_METHOD *RAND_OpenSSL(void)

{

    return &ossl_rand_meth;

}