| /* $OpenBSD: arc4random_linux.h,v 1.7 2014/07/20 20:51:13 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> |
| * |
| * 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 <errno.h> |
| #include <pthread.h> |
| #include <signal.h> |
| #include <sys/mman.h> |
| |
| #include <async_safe/log.h> |
| |
| #include "private/bionic_prctl.h" |
| |
| // Android gets these from "thread_private.h". |
| #include "thread_private.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) { |
| async_safe_fatal("getentropy failed: %s", strerror(errno)); |
| } |
| |
| volatile sig_atomic_t _rs_forked; |
| |
| static inline void |
| _rs_forkdetect(void) |
| { |
| static pid_t _rs_pid = 0; |
| pid_t pid = getpid(); |
| |
| if (_rs_pid == 0 || _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) |
| { |
| // OpenBSD's arc4random_linux.h allocates two separate mappings, but for |
| // themselves they just allocate both structs into one mapping like this. |
| struct { |
| struct _rs rs; |
| struct _rsx rsx; |
| } *p; |
| |
| if ((p = mmap(NULL, sizeof(*p), PROT_READ|PROT_WRITE, |
| MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED) |
| return (-1); |
| |
| prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, p, sizeof(*p), "arc4random data"); |
| |
| *rsp = &p->rs; |
| *rsxp = &p->rsx; |
| |
| return (0); |
| } |