1 /* $OpenBSD: arc4random_linux.h,v 1.6 2014/07/19 15:29:25 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 <pthread.h> 26 27 static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER; 28 #define _ARC4_LOCK() pthread_mutex_lock(&arc4random_mtx) 29 #define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx) 30 31 #ifdef __GLIBC__ 32 extern void *__dso_handle; 33 extern int __register_atfork(void (*)(void), void(*)(void), void (*)(void), void *); 34 #define _ARC4_ATFORK(f) __register_atfork(NULL, NULL, (f), __dso_handle) 35 #else 36 #define _ARC4_ATFORK(f) pthread_atfork(NULL, NULL, (f)) 37 #endif 38 39 static volatile sig_atomic_t _rs_forked; 40 41 static inline void 42 _rs_forkhandler(void) 43 { 44 _rs_forked = 1; 45 } 46 47 static inline void 48 _rs_forkdetect(void) 49 { 50 static pid_t _rs_pid = 0; 51 pid_t pid = getpid(); 52 53 if (_rs_pid == 0 || _rs_pid != pid || _rs_forked) { 54 _rs_pid = pid; 55 _rs_forked = 0; 56 if (rs) 57 memset(rs, 0, sizeof(*rs)); 58 } 59 } 60 61 static inline int 62 _rs_allocate(struct _rs **rsp, struct _rsx **rsxp) 63 { 64 if ((*rsp = mmap(NULL, sizeof(**rsp), PROT_READ|PROT_WRITE, 65 MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED) 66 return (-1); 67 68 if ((*rsxp = mmap(NULL, sizeof(**rsxp), PROT_READ|PROT_WRITE, 69 MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED) { 70 munmap(*rsxp, sizeof(**rsxp)); 71 return (-1); 72 } 73 74 _ARC4_ATFORK(_rs_forkhandler); 75 return (0); 76 } 77