1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #ifndef _PRIVATE_BIONIC_ARC4RANDOM_H_ 30 #define _PRIVATE_BIONIC_ARC4RANDOM_H_ 31 32 #include <stddef.h> 33 34 #include "private/KernelArgumentBlock.h" 35 36 /* 37 * arc4random aborts if it's unable to fetch entropy, which is always the case 38 * for init on devices without getrandom(2), since /dev/random hasn't been 39 * created yet. Provide a wrapper function that falls back to AT_RANDOM if 40 * we don't have getrandom and /dev/urandom is missing. 41 */ 42 void __libc_safe_arc4random_buf(void* buf, size_t n, KernelArgumentBlock& args); 43 44 /* 45 * Return true if libc has an unlimited entropy source (something other than 46 * AT_RANDOM), and arc4random* calls will always succeed. 47 */ 48 bool __libc_arc4random_has_unlimited_entropy(); 49 50 #endif 51