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/* $OpenBSD: arc4random_linux.h,v 1.11 2016/06/30 12:19:51 bcook Exp $ */
/*
* Copyright (c) 1996, David Mazieres <dm@uun.org>
* Copyright (c) 2008, Damien Miller <djm@openbsd.org>
* Copyright (c) 2013, Markus Friedl <markus@openbsd.org>
* Copyright (c) 2014, Theo de Raadt <deraadt@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* Stub functions for portability.
*/
#include <sys/mman.h>
#include <pthread.h>
#include <signal.h>
static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
#define _ARC4_LOCK() pthread_mutex_lock(&arc4random_mtx)
#define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx)
#ifdef __GLIBC__
extern void *__dso_handle;
extern int __register_atfork(void (*)(void), void(*)(void), void (*)(void), void *);
#define _ARC4_ATFORK(f) __register_atfork(NULL, NULL, (f), __dso_handle)
#else
#define _ARC4_ATFORK(f) pthread_atfork(NULL, NULL, (f))
#endif
static inline void
_getentropy_fail(void)
{
raise(SIGKILL);
}
static volatile sig_atomic_t _rs_forked;
static inline void
_rs_forkhandler(void)
{
_rs_forked = 1;
}
static inline void
_rs_forkdetect(void)
{
static pid_t _rs_pid = 0;
pid_t pid = getpid();
/* XXX unusual calls to clone() can bypass checks */
if (_rs_pid == 0 || _rs_pid == 1 || _rs_pid != pid || _rs_forked) {
_rs_pid = pid;
_rs_forked = 0;
if (rs)
memset(rs, 0, sizeof(*rs));
}
}
static inline int
_rs_allocate(struct _rs **rsp, struct _rsx **rsxp)
{
if ((*rsp = mmap(NULL, sizeof(**rsp), PROT_READ|PROT_WRITE,
MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED)
return (-1);
if ((*rsxp = mmap(NULL, sizeof(**rsxp), PROT_READ|PROT_WRITE,
MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED) {
munmap(*rsp, sizeof(**rsp));
*rsp = NULL;
return (-1);
}
_ARC4_ATFORK(_rs_forkhandler);
return (0);
}
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