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 // Android gets these from "thread_private.h".
31 #include "thread_private.h"
32 //static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
33 //#define _ARC4_LOCK() pthread_mutex_lock(&arc4random_mtx)
34 //#define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx)
35
36 #ifdef __GLIBC__
37 extern void *__dso_handle;
38 extern int __register_atfork(void (*)(void), void(*)(void), void (*)(void), void *);
39 #define _ARC4_ATFORK(f) __register_atfork(NULL, NULL, (f), __dso_handle)
40 #else
41 #define _ARC4_ATFORK(f) pthread_atfork(NULL, NULL, (f))
42 #endif
43
44 static inline void
_getentropy_fail(void)45 _getentropy_fail(void)
46 {
47 raise(SIGKILL);
48 }
49
50 static volatile sig_atomic_t _rs_forked;
51
52 static inline void
_rs_forkhandler(void)53 _rs_forkhandler(void)
54 {
55 _rs_forked = 1;
56 }
57
58 static inline void
_rs_forkdetect(void)59 _rs_forkdetect(void)
60 {
61 static pid_t _rs_pid = 0;
62 pid_t pid = getpid();
63
64 if (_rs_pid == 0 || _rs_pid != pid || _rs_forked) {
65 _rs_pid = pid;
66 _rs_forked = 0;
67 if (rs)
68 memset(rs, 0, sizeof(*rs));
69 }
70 }
71
72 static inline int
_rs_allocate(struct _rs ** rsp,struct _rsx ** rsxp)73 _rs_allocate(struct _rs **rsp, struct _rsx **rsxp)
74 {
75 if ((*rsp = mmap(NULL, sizeof(**rsp), PROT_READ|PROT_WRITE,
76 MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED)
77 return (-1);
78
79 if ((*rsxp = mmap(NULL, sizeof(**rsxp), PROT_READ|PROT_WRITE,
80 MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED) {
81 munmap(*rsxp, sizeof(**rsxp));
82 return (-1);
83 }
84
85 _ARC4_ATFORK(_rs_forkhandler);
86 return (0);
87 }
88