Use upstream OpenBSD's arc4random.
The getentropy_linux.c is lightly modified to build on Android, but we're now
completely in sync with upstream OpenBSD's arc4random implementation.
Change-Id: If32229fc28aba908035fb38703190d41ddcabc95
diff --git a/libc/upstream-openbsd/android/include/arc4random.h b/libc/upstream-openbsd/android/include/arc4random.h
new file mode 100644
index 0000000..c07257d
--- /dev/null
+++ b/libc/upstream-openbsd/android/include/arc4random.h
@@ -0,0 +1,87 @@
+/* $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 <sys/mman.h>
+
+#include <pthread.h>
+#include <signal.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)
+{
+ 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();
+
+ 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)
+{
+ 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(*rsxp, sizeof(**rsxp));
+ return (-1);
+ }
+
+ _ARC4_ATFORK(_rs_forkhandler);
+ return (0);
+}
diff --git a/libc/upstream-openbsd/android/include/openbsd-compat.h b/libc/upstream-openbsd/android/include/openbsd-compat.h
index 5827a82..34ad2c5 100644
--- a/libc/upstream-openbsd/android/include/openbsd-compat.h
+++ b/libc/upstream-openbsd/android/include/openbsd-compat.h
@@ -18,6 +18,7 @@
#define _BIONIC_OPENBSD_COMPAT_H_included
#include <sys/cdefs.h>
+#include <stddef.h> // For size_t.
#define __USE_BSD
@@ -36,6 +37,11 @@
/* OpenBSD has this, but we can't really implement it correctly on Linux. */
#define issetugid() 0
+#define explicit_bzero(p, s) memset(p, 0, s)
+
+/* We have OpenBSD's getentropy_linux.c, but we don't mention getentropy in any header. */
+__LIBC_HIDDEN__ extern int getentropy(void*, size_t);
+
/* LP32 NDK ctype.h contained references to these. */
__LIBC64_HIDDEN__ extern const short* _tolower_tab_;
__LIBC64_HIDDEN__ extern const short* _toupper_tab_;