arc4random_linux.h (2350B)
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 static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER; 31 #define _ARC4_LOCK() pthread_mutex_lock(&arc4random_mtx) 32 #define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx) 33 34 #ifdef __GLIBC__ 35 extern void *__dso_handle; 36 extern int __register_atfork(void (*)(void), void(*)(void), void (*)(void), void *); 37 #define _ARC4_ATFORK(f) __register_atfork(NULL, NULL, (f), __dso_handle) 38 #else 39 #define _ARC4_ATFORK(f) pthread_atfork(NULL, NULL, (f)) 40 #endif 41 42 static inline void 43 _getentropy_fail(void) 44 { 45 raise(SIGKILL); 46 } 47 48 static volatile sig_atomic_t _rs_forked; 49 50 static inline void 51 _rs_forkhandler(void) 52 { 53 _rs_forked = 1; 54 } 55 56 static inline void 57 _rs_forkdetect(void) 58 { 59 static pid_t _rs_pid = 0; 60 pid_t pid = getpid(); 61 62 if (_rs_pid == 0 || _rs_pid != pid || _rs_forked) { 63 _rs_pid = pid; 64 _rs_forked = 0; 65 if (rs) 66 memset(rs, 0, sizeof(*rs)); 67 } 68 } 69 70 static inline int 71 _rs_allocate(struct _rs **rsp, struct _rsx **rsxp) 72 { 73 if ((*rsp = mmap(NULL, sizeof(**rsp), PROT_READ|PROT_WRITE, 74 MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED) 75 return (-1); 76 77 if ((*rsxp = mmap(NULL, sizeof(**rsxp), PROT_READ|PROT_WRITE, 78 MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED) { 79 munmap(*rsp, sizeof(**rsp)); 80 return (-1); 81 } 82 83 _ARC4_ATFORK(_rs_forkhandler); 84 return (0); 85 }