Add <sys/random.h>.
iOS 10 has <sys/random.h> with getentropy, glibc >= 2.25 has
<sys/random.h> with getentropy and getrandom. (glibc also pollutes
<unistd.h>, but that seems like a bad idea.)
Also, all supported devices now have kernels with the getrandom system
call.
We've had these available internally for a while, but it seems like the
time is ripe to expose them.
Bug: http://b/67014255
Test: ran tests
Change-Id: I76dde1e3a2d0bc82777eea437ac193f96964f138
diff --git a/libc/include/sys/random.h b/libc/include/sys/random.h
new file mode 100644
index 0000000..3475652
--- /dev/null
+++ b/libc/include/sys/random.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef _SYS_RANDOM_H_
+#define _SYS_RANDOM_H_
+
+#include <sys/cdefs.h>
+#include <sys/types.h>
+
+#include <linux/random.h>
+
+__BEGIN_DECLS
+
+/* See also arc4random_buf in <stdlib.h>, which is available in all API levels. */
+
+int getentropy(void* __buffer, size_t __buffer_size) __wur __INTRODUCED_IN_FUTURE;
+
+ssize_t getrandom(void* __buffer, size_t __buffer_size, unsigned int __flags) __wur __INTRODUCED_IN_FUTURE;
+
+__END_DECLS
+
+#endif