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 <assert.h>
22 #include <errno.h>
23 #include <fcntl.h>
24 #include <string.h>
25 #include <sys/types.h>
26 #include <sys/stat.h>
27 #include <unistd.h>
28
29 #include "osi/include/log.h"
30 #include "osi/include/osi.h"
31
32 #define RANDOM_PATH "/dev/urandom"
33
osi_rand(void)34 int osi_rand(void) {
35 int rand;
36 int rand_fd = open(RANDOM_PATH, O_RDONLY);
37
38 if (rand_fd == INVALID_FD) {
39 LOG_ERROR(LOG_TAG, "%s can't open rand fd %s: %s ", __func__, RANDOM_PATH,
40 strerror(errno));
41 assert(0);
42 }
43
44 ssize_t read_bytes = read(rand_fd, &rand, sizeof(rand));
45 close(rand_fd);
46
47 assert(read_bytes == sizeof(rand));
48
49 if (rand < 0)
50 rand = -rand;
51
52 return rand;
53 }
54