1/* $OpenBSD: arc4random_linux.h,v 1.7 2014/07/20 20:51:13 bcook Exp $ */ 2 3/* 4 * Copyright (c) 1996, David Mazieres <dm@uun.org> 5 * Copyright (c) 2008, Damien Miller <djm@openbsd.org> 6 * Copyright (c) 2013, Markus Friedl <markus@openbsd.org> 7 * 8 * Permission to use, copy, modify, and distribute this software for any 9 * purpose with or without fee is hereby granted, provided that the above 10 * copyright notice and this permission notice appear in all copies. 11 * 12 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 13 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 14 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 15 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 16 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 17 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 18 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 19 */ 20 21/* 22 * Stub functions for portability. 23 */ 24 25#include <sys/mman.h> 26 27#include <pthread.h> 28#include <signal.h> 29 30#include "private/bionic_prctl.h" 31 32// Android gets these from "thread_private.h". 33#include "thread_private.h" 34//static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER; 35//#define _ARC4_LOCK() pthread_mutex_lock(&arc4random_mtx) 36//#define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx) 37 38#ifdef __GLIBC__ 39extern void *__dso_handle; 40extern int __register_atfork(void (*)(void), void(*)(void), void (*)(void), void *); 41#define _ARC4_ATFORK(f) __register_atfork(NULL, NULL, (f), __dso_handle) 42#else 43#define _ARC4_ATFORK(f) pthread_atfork(NULL, NULL, (f)) 44#endif 45 46static inline void 47_getentropy_fail(void) 48{ 49 raise(SIGKILL); 50} 51 52static volatile sig_atomic_t _rs_forked; 53 54static inline void 55_rs_forkhandler(void) 56{ 57 _rs_forked = 1; 58} 59 60static inline void 61_rs_forkdetect(void) 62{ 63 static pid_t _rs_pid = 0; 64 pid_t pid = getpid(); 65 66 if (_rs_pid == 0 || _rs_pid != pid || _rs_forked) { 67 _rs_pid = pid; 68 _rs_forked = 0; 69 if (rs) 70 memset(rs, 0, sizeof(*rs)); 71 } 72} 73 74static inline int 75_rs_allocate(struct _rs **rsp, struct _rsx **rsxp) 76{ 77 if ((*rsp = mmap(NULL, sizeof(**rsp), PROT_READ|PROT_WRITE, 78 MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED) 79 return (-1); 80 81 prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, *rsp, sizeof(**rsp), 82 "arc4random _rs structure"); 83 84 if ((*rsxp = mmap(NULL, sizeof(**rsxp), PROT_READ|PROT_WRITE, 85 MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED) { 86 munmap(*rsxp, sizeof(**rsxp)); 87 return (-1); 88 } 89 90 prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, *rsxp, sizeof(**rsxp), 91 "arc4random _rsx structure"); 92 93 _ARC4_ATFORK(_rs_forkhandler); 94 return (0); 95} 96