programs/random/gen_entropy.c

/**
 *  \brief Use and generate multiple entropies calls into a file
 *
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  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
 *
 *  http://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 "mbedtls/build_info.h"

#if defined(MBEDTLS_PLATFORM_C)
#    include "mbedtls/platform.h"
#else
#    include <stdio.h>
#    include <stdlib.h>
#    define mbedtls_fprintf      fprintf
#    define mbedtls_printf       printf
#    define mbedtls_exit         exit
#    define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
#    define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
#endif /* MBEDTLS_PLATFORM_C */

#if defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_FS_IO)
#    include "mbedtls/entropy.h"

#    include <stdio.h>
#endif

#if !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_FS_IO)
int main(void)
{
    mbedtls_printf("MBEDTLS_ENTROPY_C and/or MBEDTLS_FS_IO not defined.\n");
    mbedtls_exit(0);
}
#else

int main(int argc, char *argv[])
{
    FILE *f;
    int i, k, ret = 1;
    int exit_code = MBEDTLS_EXIT_FAILURE;
    mbedtls_entropy_context entropy;
    unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];

    if (argc < 2) {
        mbedtls_fprintf(stderr, "usage: %s <output filename>\n", argv[0]);
        mbedtls_exit(exit_code);
    }

    if ((f = fopen(argv[1], "wb+")) == NULL) {
        mbedtls_printf("failed to open '%s' for writing.\n", argv[1]);
        mbedtls_exit(exit_code);
    }

    mbedtls_entropy_init(&entropy);

    for (i = 0, k = 768; i < k; i++) {
        ret = mbedtls_entropy_func(&entropy, buf, sizeof(buf));
        if (ret != 0) {
            mbedtls_printf(
                "  failed\n  !  mbedtls_entropy_func returned -%04X\n",
                (unsigned int)ret);
            goto cleanup;
        }

        fwrite(buf, 1, sizeof(buf), f);

        mbedtls_printf("Generating %ldkb of data in file '%s'... %04.1f"
                       "%% done\r",
                       (long)(sizeof(buf) * k / 1024), argv[1],
                       (100 * (float)(i + 1)) / k);
        fflush(stdout);
    }

    exit_code = MBEDTLS_EXIT_SUCCESS;

cleanup:
    mbedtls_printf("\n");

    fclose(f);
    mbedtls_entropy_free(&entropy);

    mbedtls_exit(exit_code);
}
#endif /* MBEDTLS_ENTROPY_C */