libspl: move random definitions from zfs_context.h

Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes #17861

lib/libspl/include/Makefile.am

@@ -53,6 +53,7 @@ libspl_sys_HEADERS = \
 	%D%/sys/priv.h \
 	%D%/sys/processor.h \
 	%D%/sys/procfs_list.h \
+	%D%/sys/random.h \
 	%D%/sys/rwlock.h \
 	%D%/sys/simd.h \
 	%D%/sys/stack.h \

lib/libspl/include/sys/misc.h

@@ -31,6 +31,9 @@
 
 #include <sys/utsname.h>
 
+extern const char *random_path;
+extern const char *urandom_path;
+
 /*
  * Hostname information
  */

lib/libspl/include/sys/random.h

@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: CDDL-1.0
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or https://opensource.org/licenses/CDDL-1.0.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
+ * Copyright (c) 2012, 2018 by Delphix. All rights reserved.
+ * Copyright (c) 2012, Joyent, Inc. All rights reserved.
+ */
+
+#ifndef _SYS_RANDOM_H
+#define	_SYS_RANDOM_H
+
+extern int random_get_bytes(uint8_t *ptr, size_t len);
+extern int random_get_pseudo_bytes(uint8_t *ptr, size_t len);
+
+static __inline__ uint32_t
+random_in_range(uint32_t range)
+{
+	uint32_t r;
+
+	ASSERT(range != 0);
+
+	if (range == 1)
+		return (0);
+
+	(void) random_get_pseudo_bytes((uint8_t *)&r, sizeof (r));
+
+	return (r % range);
+}
+
+#endif	/* _SYS_RANDOM_H */