Add FreeBSD support to OpenZFS

Add the FreeBSD platform code to the OpenZFS repository.  As of this
commit the source can be compiled and tested on FreeBSD 11 and 12.
Subsequent commits are now required to compile on FreeBSD and Linux.
Additionally, they must pass the ZFS Test Suite on FreeBSD which is
being run by the CI.  As of this commit 1230 tests pass on FreeBSD
and there are no unexpected failures.

Reviewed-by: Sean Eric Fagan <[email protected]>
Reviewed-by: Jorgen Lundman <[email protected]>
Reviewed-by: Richard Laager <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Co-authored-by: Ryan Moeller <[email protected]>
Signed-off-by: Matt Macy <[email protected]>
Signed-off-by: Ryan Moeller <[email protected]>
Closes #898 
Closes #8987 

13 files changed, 878 insertions, 0 deletions

diff --git a/lib/libspl/include/os/Makefile.am b/lib/libspl/include/os/Makefile.am
index 09c0beec4..7b362e02a 100644
--- a/lib/libspl/include/os/Makefile.am
+++ b/lib/libspl/include/os/Makefile.am
@@ -1,3 +1,7 @@
+if BUILD_FREEBSD
+SUBDIRS = freebsd
+endif
+
 if BUILD_LINUX
 SUBDIRS = linux
 endif
diff --git a/lib/libspl/include/os/freebsd/Makefile.am b/lib/libspl/include/os/freebsd/Makefile.am
new file mode 100644
index 000000000..081839c48
--- /dev/null
+++ b/lib/libspl/include/os/freebsd/Makefile.am
@@ -0,0 +1 @@
+SUBDIRS = sys
diff --git a/lib/libspl/include/os/freebsd/sys/Makefile.am b/lib/libspl/include/os/freebsd/sys/Makefile.am
new file mode 100644
index 000000000..896c93871
--- /dev/null
+++ b/lib/libspl/include/os/freebsd/sys/Makefile.am
@@ -0,0 +1,12 @@
+libspldir = $(includedir)/libspl/sys
+libspl_HEADERS = \
+	$(top_srcdir)/lib/libspl/include/os/freebsd/sys/byteorder.h \
+	$(top_srcdir)/lib/libspl/include/os/freebsd/sys/file.h \
+	$(top_srcdir)/lib/libspl/include/os/freebsd/sys/mnttab.h \
+	$(top_srcdir)/lib/libspl/include/os/freebsd/sys/mount.h \
+	$(top_srcdir)/lib/libspl/include/os/freebsd/sys/param.h \
+	$(top_srcdir)/lib/libspl/include/os/freebsd/sys/stat.h \
+	$(top_srcdir)/lib/libspl/include/os/freebsd/sys/sysmacros.h \
+	$(top_srcdir)/lib/libspl/include/os/freebsd/sys/uio.h \
+	$(top_srcdir)/lib/libspl/include/os/freebsd/sys/vfs.h \
+	$(top_srcdir)/lib/libspl/include/os/freebsd/sys/zfs_context_os.h
diff --git a/lib/libspl/include/os/freebsd/sys/byteorder.h b/lib/libspl/include/os/freebsd/sys/byteorder.h
new file mode 100644
index 000000000..74649cc4e
--- /dev/null
+++ b/lib/libspl/include/os/freebsd/sys/byteorder.h
@@ -0,0 +1,311 @@
+/*
+ * 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 http://www.opensolaris.org/os/licensing.
+ * 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 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
+/*	  All Rights Reserved  	*/
+
+/*
+ * University Copyright- Copyright (c) 1982, 1986, 1988
+ * The Regents of the University of California
+ * All Rights Reserved
+ *
+ * University Acknowledgment- Portions of this document are derived from
+ * software developed by the University of California, Berkeley, and its
+ * contributors.
+ */
+
+#ifndef _SYS_BYTEORDER_H
+#define	_SYS_BYTEORDER_H
+
+/*
+ * XXX FIXME
+ * on FreeBSD _BIG_ENDIAN is defined on all architectures so we have
+ * to exclude _MACHINE_ENDIAN_H_ and define the bulk of it here
+ */
+
+#include <sys/cdefs.h>
+#include <sys/_types.h>
+
+/*
+ * Define the order of 32-bit words in 64-bit words.
+ */
+#define	_QUAD_HIGHWORD 1
+#define	_QUAD_LOWWORD 0
+
+/*
+ * Definitions for byte order, according to byte significance from low
+ * address to high.
+ */
+#undef _LITTLE_ENDIAN
+/* LSB first: i386, vax */
+#define	_LITTLE_ENDIAN	1234
+/* LSB first in word, MSW first in long */
+#define	_PDP_ENDIAN		3412
+
+#define	_BYTE_ORDER		_LITTLE_ENDIAN
+
+/*
+ * Deprecated variants that don't have enough underscores to be useful in more
+ * strict namespaces.
+ */
+#if __BSD_VISIBLE
+#define	LITTLE_ENDIAN	_LITTLE_ENDIAN
+#define	PDP_ENDIAN		_PDP_ENDIAN
+#define	BYTE_ORDER		_BYTE_ORDER
+#endif
+
+#define	__bswap16_gen(x)	(__uint16_t)((x) << 8 | (x) >> 8)
+#define	__bswap32_gen(x)                \
+	(((__uint32_t)__bswap16((x) & 0xffff) << 16) | __bswap16((x) >> 16))
+#define	__bswap64_gen(x)                \
+	(((__uint64_t)__bswap32((x) & 0xffffffff) << 32) | __bswap32((x) >> 32))
+
+#ifdef __GNUCLIKE_BUILTIN_CONSTANT_P
+#define	__bswap16(x)                            \
+	((__uint16_t)(__builtin_constant_p(x) ? \
+	__bswap16_gen((__uint16_t)(x)) : __bswap16_var(x)))
+#define	__bswap32(x)                    \
+	(__builtin_constant_p(x) ?      \
+	__bswap32_gen((__uint32_t)(x)) : __bswap32_var(x))
+#define	__bswap64(x)                    \
+	(__builtin_constant_p(x) ?      \
+	__bswap64_gen((__uint64_t)(x)) : __bswap64_var(x))
+#else
+/* XXX these are broken for use in static initializers. */
+#define	__bswap16(x)    __bswap16_var(x)
+#define	__bswap32(x)    __bswap32_var(x)
+#define	__bswap64(x)    __bswap64_var(x)
+#endif
+
+/* These are defined as functions to avoid multiple evaluation of x. */
+
+static __inline __uint16_t
+__bswap16_var(__uint16_t _x)
+{
+
+	return (__bswap16_gen(_x));
+}
+
+static __inline __uint32_t
+__bswap32_var(__uint32_t _x)
+{
+
+#ifdef __GNUCLIKE_ASM
+	__asm("bswap %0" : "+r" (_x));
+	return (_x);
+#else
+	return (__bswap32_gen(_x));
+#endif
+}
+#define	__htonl(x)	__bswap32(x)
+#define	__htons(x)	__bswap16(x)
+#define	__ntohl(x)	__bswap32(x)
+#define	__ntohs(x)	__bswap16(x)
+
+#include <sys/isa_defs.h>
+#include <sys/int_types.h>
+
+#if defined(__GNUC__) && defined(_ASM_INLINES) && \
+	(defined(__i386) || defined(__amd64))
+#include <asm/byteorder.h>
+#endif
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+/*
+ * macros for conversion between host and (internet) network byte order
+ */
+
+#if defined(_BIG_ENDIAN) && !defined(ntohl) && !defined(__lint)
+/* big-endian */
+#if defined(_BIG_ENDIAN) && (defined(__amd64__) || defined(__amd64))
+#error "incompatible ENDIAN / ARCH combination"
+#endif
+#define	ntohl(x)	(x)
+#define	ntohs(x)	(x)
+#define	htonl(x)	(x)
+#define	htons(x)	(x)
+
+#elif !defined(ntohl) /* little-endian */
+
+#ifndef	_IN_PORT_T
+#define	_IN_PORT_T
+typedef uint16_t in_port_t;
+#endif
+
+#ifndef	_IN_ADDR_T
+#define	_IN_ADDR_T
+typedef uint32_t in_addr_t;
+#endif
+
+#if !defined(_XPG4_2) || defined(__EXTENSIONS__) || defined(_XPG5)
+extern	uint32_t htonl(uint32_t);
+extern	uint16_t htons(uint16_t);
+extern 	uint32_t ntohl(uint32_t);
+extern	uint16_t ntohs(uint16_t);
+#else
+extern	in_addr_t htonl(in_addr_t);
+extern	in_port_t htons(in_port_t);
+extern 	in_addr_t ntohl(in_addr_t);
+extern	in_port_t ntohs(in_port_t);
+#endif	/* !defined(_XPG4_2) || defined(__EXTENSIONS__) || defined(_XPG5) */
+#endif
+
+#if !defined(_XPG4_2) || defined(__EXTENSIONS__)
+
+/*
+ * Macros to reverse byte order
+ */
+#define	BSWAP_8(x)	((x) & 0xff)
+#define	BSWAP_16(x)	((BSWAP_8(x) << 8) | BSWAP_8((x) >> 8))
+#define	BSWAP_32(x)	((BSWAP_16(x) << 16) | BSWAP_16((x) >> 16))
+#define	BSWAP_64(x)	((BSWAP_32(x) << 32) | BSWAP_32((x) >> 32))
+
+#define	BMASK_8(x)	((x) & 0xff)
+#define	BMASK_16(x)	((x) & 0xffff)
+#define	BMASK_32(x)	((x) & 0xffffffff)
+#define	BMASK_64(x)	(x)
+
+/*
+ * Macros to convert from a specific byte order to/from native byte order
+ */
+#ifdef _BIG_ENDIAN
+#define	BE_8(x)		BMASK_8(x)
+#define	BE_16(x)	BMASK_16(x)
+#define	BE_32(x)	BMASK_32(x)
+#define	BE_64(x)	BMASK_64(x)
+#define	LE_8(x)		BSWAP_8(x)
+#define	LE_16(x)	BSWAP_16(x)
+#define	LE_32(x)	BSWAP_32(x)
+#define	LE_64(x)	BSWAP_64(x)
+#else
+#define	LE_8(x)		BMASK_8(x)
+#define	LE_16(x)	BMASK_16(x)
+#define	LE_32(x)	BMASK_32(x)
+#define	LE_64(x)	BMASK_64(x)
+#define	BE_8(x)		BSWAP_8(x)
+#define	BE_16(x)	BSWAP_16(x)
+#define	BE_32(x)	BSWAP_32(x)
+#define	BE_64(x)	BSWAP_64(x)
+#endif
+
+#ifdef _BIG_ENDIAN
+static __inline__ uint64_t
+htonll(uint64_t n)
+{
+	return (n);
+}
+
+static __inline__ uint64_t
+ntohll(uint64_t n)
+{
+	return (n);
+}
+#else
+static __inline__ uint64_t
+htonll(uint64_t n)
+{
+	return ((((uint64_t)htonl(n)) << 32) + htonl(n >> 32));
+}
+
+static __inline__ uint64_t
+ntohll(uint64_t n)
+{
+	return ((((uint64_t)ntohl(n)) << 32) + ntohl(n >> 32));
+}
+#endif
+
+/*
+ * Macros to read unaligned values from a specific byte order to
+ * native byte order
+ */
+
+#define	BE_IN8(xa) \
+	*((uint8_t *)(xa))
+
+#define	BE_IN16(xa) \
+	(((uint16_t)BE_IN8(xa) << 8) | BE_IN8((uint8_t *)(xa)+1))
+
+#define	BE_IN32(xa) \
+	(((uint32_t)BE_IN16(xa) << 16) | BE_IN16((uint8_t *)(xa)+2))
+
+#define	BE_IN64(xa) \
+	(((uint64_t)BE_IN32(xa) << 32) | BE_IN32((uint8_t *)(xa)+4))
+
+#define	LE_IN8(xa) \
+	*((uint8_t *)(xa))
+
+#define	LE_IN16(xa) \
+	(((uint16_t)LE_IN8((uint8_t *)(xa) + 1) << 8) | LE_IN8(xa))
+
+#define	LE_IN32(xa) \
+	(((uint32_t)LE_IN16((uint8_t *)(xa) + 2) << 16) | LE_IN16(xa))
+
+#define	LE_IN64(xa) \
+	(((uint64_t)LE_IN32((uint8_t *)(xa) + 4) << 32) | LE_IN32(xa))
+
+/*
+ * Macros to write unaligned values from native byte order to a specific byte
+ * order.
+ */
+
+#define	BE_OUT8(xa, yv) *((uint8_t *)(xa)) = (uint8_t)(yv);
+
+#define	BE_OUT16(xa, yv) \
+	BE_OUT8((uint8_t *)(xa) + 1, yv); \
+	BE_OUT8((uint8_t *)(xa), (yv) >> 8);
+
+#define	BE_OUT32(xa, yv) \
+	BE_OUT16((uint8_t *)(xa) + 2, yv); \
+	BE_OUT16((uint8_t *)(xa), (yv) >> 16);
+
+#define	BE_OUT64(xa, yv) \
+	BE_OUT32((uint8_t *)(xa) + 4, yv); \
+	BE_OUT32((uint8_t *)(xa), (yv) >> 32);
+
+#define	LE_OUT8(xa, yv) *((uint8_t *)(xa)) = (uint8_t)(yv);
+
+#define	LE_OUT16(xa, yv) \
+	LE_OUT8((uint8_t *)(xa), yv); \
+	LE_OUT8((uint8_t *)(xa) + 1, (yv) >> 8);
+
+#define	LE_OUT32(xa, yv) \
+	LE_OUT16((uint8_t *)(xa), yv); \
+	LE_OUT16((uint8_t *)(xa) + 2, (yv) >> 16);
+
+#define	LE_OUT64(xa, yv) \
+	LE_OUT32((uint8_t *)(xa), yv); \
+	LE_OUT32((uint8_t *)(xa) + 4, (yv) >> 32);
+
+#endif	/* !defined(_XPG4_2) || defined(__EXTENSIONS__) */
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif /* _SYS_BYTEORDER_H */
diff --git a/lib/libspl/include/os/freebsd/sys/file.h b/lib/libspl/include/os/freebsd/sys/file.h
new file mode 100644
index 000000000..27fd2888f
--- /dev/null
+++ b/lib/libspl/include/os/freebsd/sys/file.h
@@ -0,0 +1,42 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (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 http://www.opensolaris.org/os/licensing.
+ * 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 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#ifndef _LIBSPL_SYS_FILE_H
+#define	_LIBSPL_SYS_FILE_H
+
+#include_next <sys/file.h>
+
+#define	FCREAT	O_CREAT
+#define	FTRUNC	O_TRUNC
+#define	FSYNC	O_SYNC
+#define	FDSYNC	O_DSYNC
+#define	FEXCL	O_EXCL
+
+#define	FNODSYNC	0x10000	/* fsync pseudo flag */
+#define	FNOFOLLOW	0x20000	/* don't follow symlinks */
+#define	FIGNORECASE	0x80000	/* request case-insensitive lookups */
+
+#endif
diff --git a/lib/libspl/include/os/freebsd/sys/mnttab.h b/lib/libspl/include/os/freebsd/sys/mnttab.h
new file mode 100644
index 000000000..eb6ea2433
--- /dev/null
+++ b/lib/libspl/include/os/freebsd/sys/mnttab.h
@@ -0,0 +1,85 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (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 http://www.opensolaris.org/os/licensing.
+ * 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) 1984, 1986, 1987, 1988, 1989 AT&T */
+/*  All Rights Reserved  */
+/*
+ * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+/* Copyright 2006 Ricardo Correia */
+
+#ifndef _SYS_MNTTAB_H
+#define	_SYS_MNTTAB_H
+
+#include <stdio.h>
+#include <sys/types.h>
+
+#ifdef MNTTAB
+#undef MNTTAB
+#endif /* MNTTAB */
+
+#include <paths.h>
+#include <sys/mount.h>
+#define	MNTTAB		_PATH_DEVZERO
+#define	MS_NOMNTTAB		0x0
+#define	MS_RDONLY		0x1
+#define	umount2(p, f)	unmount(p, f)
+#define	MNT_LINE_MAX	4096
+
+#define	MNT_TOOLONG	1	/* entry exceeds MNT_LINE_MAX */
+#define	MNT_TOOMANY	2	/* too many fields in line */
+#define	MNT_TOOFEW	3	/* too few fields in line */
+
+struct mnttab {
+	char *mnt_special;
+	char *mnt_mountp;
+	char *mnt_fstype;
+	char *mnt_mntopts;
+};
+
+/*
+ * NOTE: fields in extmnttab should match struct mnttab till new fields
+ * are encountered, this allows hasmntopt to work properly when its arg is
+ * a pointer to an extmnttab struct cast to a mnttab struct pointer.
+ */
+
+struct extmnttab {
+	char *mnt_special;
+	char *mnt_mountp;
+	char *mnt_fstype;
+	char *mnt_mntopts;
+	uint_t mnt_major;
+	uint_t mnt_minor;
+};
+
+struct stat64;
+struct statfs;
+
+extern int getmntany(FILE *fp, struct mnttab *mp, struct mnttab *mpref);
+extern int _sol_getmntent(FILE *fp, struct mnttab *mp);
+extern int getextmntent(const char *path, struct extmnttab *entry,
+    struct stat64 *statbuf);
+extern void statfs2mnttab(struct statfs *sfs, struct mnttab *mp);
+char *hasmntopt(struct mnttab *mnt, char *opt);
+int getmntent(FILE *fp, struct mnttab *mp);
+
+#endif
diff --git a/lib/libspl/include/os/freebsd/sys/mount.h b/lib/libspl/include/os/freebsd/sys/mount.h
new file mode 100644
index 000000000..b40239100
--- /dev/null
+++ b/lib/libspl/include/os/freebsd/sys/mount.h
@@ -0,0 +1,108 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (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 http://www.opensolaris.org/os/licensing.
+ * 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 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+
+#ifndef _LIBSPL_SYS_MOUNT_H
+#define	_LIBSPL_SYS_MOUNT_H
+
+#undef _SYS_MOUNT_H_
+#include_next <sys/mount.h>
+
+#include <assert.h>
+#include <string.h>
+#include <stdlib.h>
+
+/*
+ * Some old glibc headers don't define BLKGETSIZE64
+ * and we don't want to require the kernel headers
+ */
+#if !defined(BLKGETSIZE64)
+#define	BLKGETSIZE64		_IOR(0x12, 114, size_t)
+#endif
+
+/*
+ * Some old glibc headers don't correctly define MS_DIRSYNC and
+ * instead use the enum name S_WRITE.  When using these older
+ * headers define MS_DIRSYNC to be S_WRITE.
+ */
+#if !defined(MS_DIRSYNC)
+#define	MS_DIRSYNC		S_WRITE
+#endif
+
+/*
+ * Some old glibc headers don't correctly define MS_POSIXACL and
+ * instead leave it undefined.  When using these older headers define
+ * MS_POSIXACL to the reserved value of (1<<16).
+ */
+#if !defined(MS_POSIXACL)
+#define	MS_POSIXACL		(1<<16)
+#endif
+
+#define	MS_NOSUID	MNT_NOSUID
+#define	MS_NOEXEC	MNT_NOEXEC
+#define	MS_NODEV	0
+#define	S_WRITE		0
+#define	MS_BIND		0
+#define	MS_REMOUNT	0
+#define	MS_SYNCHRONOUS	MNT_SYNCHRONOUS
+
+#define	MS_USERS	(MS_NOEXEC|MS_NOSUID|MS_NODEV)
+#define	MS_OWNER	(MS_NOSUID|MS_NODEV)
+#define	MS_GROUP	(MS_NOSUID|MS_NODEV)
+#define	MS_COMMENT	0
+
+/*
+ * Older glibc <sys/mount.h> headers did not define all the available
+ * umount2(2) flags.  Both MNT_FORCE and MNT_DETACH are supported in the
+ * kernel back to 2.4.11 so we define them correctly if they are missing.
+ */
+#ifdef MNT_FORCE
+#define	MS_FORCE	MNT_FORCE
+#else
+#define	MS_FORCE	0x00000001
+#endif /* MNT_FORCE */
+
+#ifdef MNT_DETACH
+#define	MS_DETACH	MNT_DETACH
+#else
+#define	MS_DETACH	0x00000002
+#endif /* MNT_DETACH */
+
+/*
+ * Overlay mount is default in Linux, but for solaris/zfs
+ * compatibility, MS_OVERLAY is defined to explicitly have the user
+ * provide a flag (-O) to mount over a non empty directory.
+ */
+#define	MS_OVERLAY	0x00000004
+
+/*
+ * MS_CRYPT indicates that encryption keys should be loaded if they are not
+ * already available. This is not defined in glibc, but it is never seen by
+ * the kernel so it will not cause any problems.
+ */
+#define	MS_CRYPT	0x00000008
+
+#endif /* _LIBSPL_SYS_MOUNT_H */
diff --git a/lib/libspl/include/os/freebsd/sys/param.h b/lib/libspl/include/os/freebsd/sys/param.h
new file mode 100644
index 000000000..c0ad8d679
--- /dev/null
+++ b/lib/libspl/include/os/freebsd/sys/param.h
@@ -0,0 +1,70 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (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 http://www.opensolaris.org/os/licensing.
+ * 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 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#ifndef _LIBSPL_SYS_PARAM_H
+#define	_LIBSPL_SYS_PARAM_H
+
+#include_next <sys/param.h>
+#include <unistd.h>
+
+/*
+ * File system parameters and macros.
+ *
+ * The file system is made out of blocks of at most MAXBSIZE units,
+ * with smaller units (fragments) only in the last direct block.
+ * MAXBSIZE primarily determines the size of buffers in the buffer
+ * pool. It may be made larger without any effect on existing
+ * file systems; however making it smaller may make some file
+ * systems unmountable.
+ *
+ * Note that the blocked devices are assumed to have DEV_BSIZE
+ * "sectors" and that fragments must be some multiple of this size.
+ */
+#define	MAXNAMELEN	256
+
+#define	UID_NOBODY	60001		/* user ID no body */
+#define	GID_NOBODY	UID_NOBODY
+#define	UID_NOACCESS	60002		/* user ID no access */
+
+#define	MAXUID		UINT32_MAX	/* max user id */
+#define	MAXPROJID	MAXUID		/* max project id */
+
+#ifdef	PAGESIZE
+#undef	PAGESIZE
+#endif /* PAGESIZE */
+
+extern size_t spl_pagesize(void);
+#define	PAGESIZE	(spl_pagesize())
+
+extern int execvpe(const char *name, char * const argv[], char * const envp[]);
+
+struct zfs_handle;
+/*
+ * Attach/detach the given filesystem to/from the given jail.
+ */
+extern int zfs_jail(struct zfs_handle *zhp, int jailid, int attach);
+
+#endif
diff --git a/lib/libspl/include/os/freebsd/sys/stat.h b/lib/libspl/include/os/freebsd/sys/stat.h
new file mode 100644
index 000000000..82c86262f
--- /dev/null
+++ b/lib/libspl/include/os/freebsd/sys/stat.h
@@ -0,0 +1,71 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (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 http://www.opensolaris.org/os/licensing.
+ * 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) 2010, Oracle and/or its affiliates. All rights reserved.
+ */
+
+#ifndef _LIBSPL_SYS_STAT_H
+#define	_LIBSPL_SYS_STAT_H
+
+#include_next <sys/stat.h>
+
+#include <sys/mount.h> /* for BLKGETSIZE64 */
+
+#define	stat64	stat
+
+#define	MAXOFFSET_T	OFF_MAX
+
+#ifndef _KERNEL
+#include <sys/disk.h>
+
+static __inline int
+fstat64(int fd, struct stat *sb)
+{
+	int ret;
+
+	ret = fstat(fd, sb);
+	if (ret == 0) {
+		if (S_ISCHR(sb->st_mode))
+			(void) ioctl(fd, DIOCGMEDIASIZE, &sb->st_size);
+	}
+	return (ret);
+}
+#endif
+
+/*
+ * Emulate Solaris' behavior of returning the block device size in fstat64().
+ */
+static inline int
+fstat64_blk(int fd, struct stat64 *st)
+{
+	if (fstat64(fd, st) == -1)
+		return (-1);
+
+	/* In Linux we need to use an ioctl to get the size of a block device */
+	if (S_ISBLK(st->st_mode)) {
+		if (ioctl(fd, BLKGETSIZE64, &st->st_size) != 0)
+			return (-1);
+	}
+
+	return (0);
+}
+#endif /* _LIBSPL_SYS_STAT_H */
diff --git a/lib/libspl/include/os/freebsd/sys/sysmacros.h b/lib/libspl/include/os/freebsd/sys/sysmacros.h
new file mode 100644
index 000000000..d9639d27b
--- /dev/null
+++ b/lib/libspl/include/os/freebsd/sys/sysmacros.h
@@ -0,0 +1 @@
+/* keep me */
diff --git a/lib/libspl/include/os/freebsd/sys/uio.h b/lib/libspl/include/os/freebsd/sys/uio.h
new file mode 100644
index 000000000..d978b6ad0
--- /dev/null
+++ b/lib/libspl/include/os/freebsd/sys/uio.h
@@ -0,0 +1,98 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (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 http://www.opensolaris.org/os/licensing.
+ * 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 2005 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
+/*	  All Rights Reserved  	*/
+
+/*
+ * University Copyright- Copyright (c) 1982, 1986, 1988
+ * The Regents of the University of California
+ * All Rights Reserved
+ *
+ * University Acknowledgment- Portions of this document are derived from
+ * software developed by the University of California, Berkeley, and its
+ * contributors.
+ */
+
+#ifndef	_LIBSPL_SYS_UIO_H
+#define	_LIBSPL_SYS_UIO_H
+
+#include_next <sys/uio.h>
+
+typedef struct iovec iovec_t;
+typedef enum uio_seg  uio_seg_t;
+
+typedef struct uio {
+	struct iovec	*uio_iov;	/* pointer to array of iovecs */
+	int		uio_iovcnt;	/* number of iovecs */
+	offset_t	uio_loffset;	/* file offset */
+	uio_seg_t	uio_segflg;	/* address space (kernel or user) */
+	uint16_t	uio_fmode;	/* file mode flags */
+	uint16_t	uio_extflg;	/* extended flags */
+	offset_t	uio_limit;	/* u-limit (maximum byte offset) */
+	ssize_t		uio_resid;	/* residual count */
+} uio_t;
+
+typedef enum xuio_type {
+	UIOTYPE_ASYNCIO,
+	UIOTYPE_ZEROCOPY,
+} xuio_type_t;
+
+#define	UIOA_IOV_MAX	16
+
+typedef struct uioa_page_s {		/* locked uio_iov state */
+	int	uioa_pfncnt;		/* count of pfn_t(s) in *uioa_ppp */
+	void	**uioa_ppp;		/* page_t or pfn_t array */
+	caddr_t	uioa_base;		/* address base */
+	size_t	uioa_len;		/* span length */
+} uioa_page_t;
+
+typedef struct xuio {
+	uio_t xu_uio;				/* embedded UIO structure */
+
+	/* Extended uio fields */
+	enum xuio_type xu_type;			/* uio type */
+	union {
+		struct {
+			uint32_t xu_a_state;	/* state of async i/o */
+			ssize_t xu_a_mbytes;	/* bytes moved */
+			uioa_page_t *xu_a_lcur;	/* uioa_locked[] pointer */
+			void **xu_a_lppp;	/* lcur->uioa_pppp[] pointer */
+			void *xu_a_hwst[4];	/* opaque hardware state */
+			uioa_page_t xu_a_locked[UIOA_IOV_MAX];
+		} xu_aio;
+
+		struct {
+			int xu_zc_rw;		/* read or write buffer */
+			void *xu_zc_priv;	/* fs specific */
+		} xu_zc;
+	} xu_ext;
+} xuio_t;
+
+#define	XUIO_XUZC_PRIV(xuio)	xuio->xu_ext.xu_zc.xu_zc_priv
+#define	XUIO_XUZC_RW(xuio)	xuio->xu_ext.xu_zc.xu_zc_rw
+
+#endif	/* _SYS_UIO_H */
diff --git a/lib/libspl/include/os/freebsd/sys/vfs.h b/lib/libspl/include/os/freebsd/sys/vfs.h
new file mode 100644
index 000000000..55eb3c23b
--- /dev/null
+++ b/lib/libspl/include/os/freebsd/sys/vfs.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2020 iXsystems, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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 AUTHORS 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 AUTHORS 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.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef ZFS_SYS_VFS_H_
+#define	ZFS_SYS_VFS_H_
+
+#include_next <sys/statvfs.h>
+
+int fsshare(const char *, const char *, const char *);
+int fsunshare(const char *, const char *);
+
+#endif /* !ZFS_SYS_VFS_H_ */
diff --git a/lib/libspl/include/os/freebsd/sys/zfs_context_os.h b/lib/libspl/include/os/freebsd/sys/zfs_context_os.h
new file mode 100644
index 000000000..25b5a47df
--- /dev/null
+++ b/lib/libspl/include/os/freebsd/sys/zfs_context_os.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2020 iXsystems, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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 AUTHORS 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 AUTHORS 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.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef ZFS_CONTEXT_OS_H_
+#define	ZFS_CONTEXT_OS_H_
+
+#if BYTE_ORDER != BIG_ENDIAN
+#undef _BIG_ENDIAN
+#endif
+
+#define	ZFS_EXPORTS_PATH	"/etc/zfs/exports"
+
+#endif