1/******************************************************************************
2 *
3 *  Copyright (C) 2016 Google, Inc.
4 *
5 *  Licensed under the Apache License, Version 2.0 (the "License");
6 *  you may not use this file except in compliance with the License.
7 *  You may obtain a copy of the License at:
8 *
9 *  http://www.apache.org/licenses/LICENSE-2.0
10 *
11 *  Unless required by applicable law or agreed to in writing, software
12 *  distributed under the License is distributed on an "AS IS" BASIS,
13 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 *  See the License for the specific language governing permissions and
15 *  limitations under the License.
16 *
17 ******************************************************************************/
18
19#define LOG_TAG "bt_osi_rand"
20
21#include <base/logging.h>
22#include <errno.h>
23#include <fcntl.h>
24#include <stdio.h>
25#include <string.h>
26#include <sys/stat.h>
27#include <sys/types.h>
28#include <unistd.h>
29
30#include "osi/include/log.h"
31#include "osi/include/osi.h"
32
33#define RANDOM_PATH "/dev/urandom"
34
35int osi_rand(void) {
36  int rand;
37  int rand_fd = open(RANDOM_PATH, O_RDONLY);
38
39  if (rand_fd == INVALID_FD) {
40    LOG_ERROR(LOG_TAG, "%s can't open rand fd %s: %s ", __func__, RANDOM_PATH,
41              strerror(errno));
42    CHECK(rand_fd != INVALID_FD);
43  }
44
45  ssize_t read_bytes = read(rand_fd, &rand, sizeof(rand));
46  close(rand_fd);
47
48  CHECK(read_bytes == sizeof(rand));
49
50  if (rand < 0) rand = -rand;
51
52  return rand;
53}
54