/* SPDX-License-Identifier: BSD-2-Clause */

/*
 * Copyright (c) 2017 embedded brains GmbH & Co. KG
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "tmacros.h"

#include <rtems.h>
#include <unistd.h>
#include <assert.h>

const char rtems_test_name[] = "GETENTROPY 1";

#define TEST_MAX_BYTES 32
#define TEST_GUARD_BYTES 32
#define TEST_GUARD 0xA5

static char entropy_buffer1 [TEST_MAX_BYTES + TEST_GUARD_BYTES];
static char entropy_buffer2 [TEST_MAX_BYTES + TEST_GUARD_BYTES];
static char guard_buffer [TEST_MAX_BYTES + TEST_GUARD_BYTES];

static void test_getentropy(size_t nr_bytes)
{
  int rv;
  size_t try = 1;

  /*
   * For very small patterns, the probability that two random patterns are the
   * same is quite high. Therefore retry the test for these a few times.
   */
  if (nr_bytes < 4) {
    try = 4;
  }

  do {
    --try;

    /* Fill buffers with guard pattern */
    memset(entropy_buffer1, TEST_GUARD, sizeof(entropy_buffer1));
    memset(entropy_buffer2, TEST_GUARD, sizeof(entropy_buffer2));
    memset(guard_buffer, TEST_GUARD, sizeof(entropy_buffer2));

    /* Get entropy with the given size */
    rv = getentropy(entropy_buffer1, nr_bytes);
    assert(rv == 0);
    rv = getentropy(entropy_buffer2, nr_bytes);
    assert(rv == 0);

    /* Check guard pattern */
    rv = memcmp(entropy_buffer1 + nr_bytes, guard_buffer + nr_bytes,
        sizeof(entropy_buffer1) - nr_bytes);
    assert(rv == 0);
    rv = memcmp(entropy_buffer2 + nr_bytes, guard_buffer + nr_bytes,
        sizeof(entropy_buffer2) - nr_bytes);
    assert(rv == 0);

    /* Make sure that buffers are not the same */
    rv = memcmp(entropy_buffer1, entropy_buffer2, sizeof(entropy_buffer1));
  } while (try > 0 && rv == 0);
  assert(rv != 0);
}

static void Init(rtems_task_argument arg)
{
  size_t i;

  TEST_BEGIN();

  for (i = 1; i <= TEST_MAX_BYTES; ++i) {
    test_getentropy(i);
  }

  TEST_END();

  rtems_test_exit(0);
}

#define CONFIGURE_APPLICATION_DOES_NOT_NEED_CLOCK_DRIVER
#define CONFIGURE_APPLICATION_NEEDS_SIMPLE_CONSOLE_DRIVER

#define CONFIGURE_MAXIMUM_TASKS 1

#define CONFIGURE_INITIAL_EXTENSIONS RTEMS_TEST_INITIAL_EXTENSION

#define CONFIGURE_RTEMS_INIT_TASKS_TABLE

#define CONFIGURE_INIT

#include <rtems/confdefs.h>