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