loader: zfs should support bootonce an nextboot

bootonce feature is temporary, one time boot, activated by
"bectl activate -t BE", "bectl activate -T BE" will reset the bootonce flag.

By default, the bootonce setting is reset on attempt to boot and the next
boot will use previously active BE.

By setting zfs_bootonce_activate="YES" in rc.conf, the bootonce BE will
be set permanently active.

bootonce dataset name is recorded in boot pool labels, bootenv area.

in case of nextboot, the nextboot_enable boolean variable is recorded in
freebsd:nvstore nvlist, also stored in boot pool label bootenv area.
On boot, the loader will process /boot/nextboot.conf if nextboot_enable
is "YES", and will set nextboot_enable to "NO", preventing /boot/nextboot.conf
processing on next boot.

bootonce and nextboot features are usable in both UEFI and BIOS boot.

To use bootonce/nextboot features, the boot loader needs to be updated on disk;
if loader.efi is stored on ESP, then ESP needs to be updated and
for BIOS boot, stage2 (zfsboot or gptzfsboot) needs to be updated
(gpart or other tools).

At this time, only lua loader is updated.

Sponsored by:	Netflix, Klara Inc.
Differential Revision:	https://reviews.freebsd.org/D25512

9 files changed, 340 insertions, 145 deletions

diff --git a/sbin/bectl/Makefile b/sbin/bectl/Makefile
index e261c85e1e10..6fa84f48661d 100644
--- a/sbin/bectl/Makefile
+++ b/sbin/bectl/Makefile
@@ -12,6 +12,7 @@ LIBADD+= be \
 	nvpair \
 	spl \
 	util \
+	zfsbootenv
 
 CFLAGS+= -DIN_BASE
 CFLAGS+= -I${SRCTOP}/sys/contrib/openzfs/include
diff --git a/sbin/bectl/bectl.8 b/sbin/bectl/bectl.8
index e45bc6b99551..0638a0c10ecb 100644
--- a/sbin/bectl/bectl.8
+++ b/sbin/bectl/bectl.8
@@ -17,7 +17,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd August 17, 2020
+.Dd August 25, 2020
 .Dt BECTL 8
 .Os
 .Sh NAME
@@ -26,7 +26,7 @@
 .Sh SYNOPSIS
 .Nm
 .Cm activate
-.Op Fl t
+.Op Fl t | Fl T
 .Ar beName
 .Nm
 .Cm check
@@ -95,7 +95,7 @@ The following commands are supported by
 .Bl -tag -width activate
 .It Xo
 .Cm activate
-.Op Fl t
+.Op Fl t | Fl T
 .Ar beName
 .Xc
 Activate the given
@@ -104,6 +104,13 @@ as the default boot filesystem.
 If the
 .Fl t
 flag is given, this takes effect only for the next boot.
+Flag
+.Fl T
+removes temporary boot once configuration.
+Without temporary configuration, the next boot will use zfs dataset specified
+in boot pool
+.Ar bootfs
+property.
 .It Xo
 .Cm check
 .Xc
@@ -260,8 +267,10 @@ field indicates whether the boot environment is active now
 .Pq Em \&N ;
 active on reboot
 .Pq Em \&R ;
-or both
-.Pq Em \&NR .
+is used on next boot once
+.Pq Em \&T ;
+or combination of
+.Pq Em \&NRT .
 .Pp
 .Bl -tag -width indent
 .It Fl a
diff --git a/sbin/bectl/bectl.c b/sbin/bectl/bectl.c
index 31ece42c6ff2..8a319a0d67f6 100644
--- a/sbin/bectl/bectl.c
+++ b/sbin/bectl/bectl.c
@@ -74,6 +74,7 @@ usage(bool explicit)
 	    "\tbectl add (path)*\n"
 #endif
 	    "\tbectl activate [-t] beName\n"
+	    "\tbectl activate [-T]\n"
 	    "\tbectl check\n"
 	    "\tbectl create [-r] [-e {nonActiveBe | beName@snapshot}] beName\n"
 	    "\tbectl create [-r] beName@snapshot\n"
@@ -141,14 +142,22 @@ static int
 bectl_cmd_activate(int argc, char *argv[])
 {
 	int err, opt;
-	bool temp;
+	bool temp, reset;
 
 	temp = false;
-	while ((opt = getopt(argc, argv, "t")) != -1) {
+	reset = false;
+	while ((opt = getopt(argc, argv, "tT")) != -1) {
 		switch (opt) {
 		case 't':
+			if (reset)
+				return (usage(false));
 			temp = true;
 			break;
+		case 'T':
+			if (temp)
+				return (usage(false));
+			reset = true;
+			break;
 		default:
 			fprintf(stderr, "bectl activate: unknown option '-%c'\n",
 			    optopt);
@@ -159,11 +168,18 @@ bectl_cmd_activate(int argc, char *argv[])
 	argc -= optind;
 	argv += optind;
 
-	if (argc != 1) {
+	if (argc != 1 && (!reset || argc != 0)) {
 		fprintf(stderr, "bectl activate: wrong number of arguments\n");
 		return (usage(false));
 	}
 
+	if (reset) {
+		if ((err = be_deactivate(be, NULL, reset)) == 0)
+			printf("Temporary activation removed\n");
+		else
+			printf("Failed to remove temporary activation\n");
+		return (err);
+	}
 
 	/* activate logic goes here */
 	if ((err = be_activate(be, argv[0], temp)) != 0)
diff --git a/sbin/bectl/bectl_list.c b/sbin/bectl/bectl_list.c
index 757a773e6d32..e43c3000d8f2 100644
--- a/sbin/bectl/bectl_list.c
+++ b/sbin/bectl/bectl_list.c
@@ -182,7 +182,7 @@ print_info(const char *name, nvlist_t *dsprops, struct printc *pc)
 	const char *oname;
 	char *dsname, *propstr;
 	int active_colsz;
-	boolean_t active_now, active_reboot;
+	boolean_t active_now, active_reboot, bootonce;
 
 	dsname = NULL;
 	originprops = NULL;
@@ -230,6 +230,11 @@ print_info(const char *name, nvlist_t *dsprops, struct printc *pc)
 		printf("R");
 		active_colsz--;
 	}
+	if (nvlist_lookup_boolean_value(dsprops, "bootonce",
+	    &bootonce) == 0 && bootonce) {
+		printf("T");
+		active_colsz--;
+	}
 	if (active_colsz == pc->active_colsz_def) {
 		printf("-");
 		active_colsz--;
diff --git a/sbin/reboot/nextboot.8 b/sbin/reboot/nextboot.8
index 8b72b9ad10de..d1e8cc38788e 100644
--- a/sbin/reboot/nextboot.8
+++ b/sbin/reboot/nextboot.8
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd April 9, 2016
+.Dd September 19, 2020
 .Dt NEXTBOOT 8
 .Os
 .Sh NAME
@@ -136,8 +136,3 @@ It is also my first attempt to write in Forth.
 Finally, it does some evil things like writing to the file system before it
 has been checked.
 If it scrambles your file system, do not blame me.
-.Pp
-.Xr loader 8
-is only able to read ZFS, not write to it.
-.Pa nextboot.conf
-will NOT be reset in case of a kernel boot failure.
diff --git a/sbin/reboot/nextboot.sh b/sbin/reboot/nextboot.sh
index e975215f695a..c2d1076337b9 100644
--- a/sbin/reboot/nextboot.sh
+++ b/sbin/reboot/nextboot.sh
@@ -33,6 +33,7 @@ delete="NO"
 kenv=
 force="NO"
 nextboot_file="/boot/nextboot.conf"
+zfs=
 
 add_kenv()
 {
@@ -106,26 +107,26 @@ if [ -n "${kernel}" -a ${force} = "NO" -a ! -d /boot/${kernel} ]; then
 	exit 1
 fi
 
-df -Tn "/boot/" 2>/dev/null | while read _fs _type _other ; do
+zfs=$(df -Tn "/boot/" 2>/dev/null | while read _fs _type _other ; do
 	[ "zfs" = "${_type}" ] || continue
-	cat 1>&2 <<-EOF
-		WARNING: loader(8) has only R/O support for ZFS
-		nextboot.conf will NOT be reset in case of kernel boot failure
-	EOF
-done
+	echo "${_fs%/ROOT/*}"
+done)
 
 set -e
 
 nextboot_tmp=$(mktemp $(dirname ${nextboot_file})/nextboot.XXXXXX)
 
-if [ ${append} = "YES" -a -f ${nextboot_file} ]; then
-	cp -f ${nextboot_file} ${nextboot_tmp}
-fi
-
+if [ -n ${zfs} ]; then
+	zfsbootcfg -z ${zfs} -n freebsd:nvstore -k nextboot_enable -v YES
+	cat >> ${nextboot_tmp} << EOF
+$kenv
+EOF
+else
 cat >> ${nextboot_tmp} << EOF
 nextboot_enable="YES"
 $kenv
 EOF
+fi
 
 fsync ${nextboot_tmp}
 
diff --git a/sbin/zfsbootcfg/Makefile b/sbin/zfsbootcfg/Makefile
index 8bc73ffa1e06..566ba2261705 100644
--- a/sbin/zfsbootcfg/Makefile
+++ b/sbin/zfsbootcfg/Makefile
@@ -2,14 +2,9 @@
 # $FreeBSD$
 
 PROG=	zfsbootcfg
-WARNS?=	2
 MAN=	zfsbootcfg.8
 
-LIBADD+=zfs
-LIBADD+=nvpair
-LIBADD+=umem
-LIBADD+=uutil
-LIBADD+=geom
+LIBADD+=zfsbootenv
 
 CFLAGS+= -DIN_BASE
 CFLAGS+= -I${SRCTOP}/sys/contrib/openzfs/include
diff --git a/sbin/zfsbootcfg/zfsbootcfg.8 b/sbin/zfsbootcfg/zfsbootcfg.8
index 8b9b36742db7..797e5d4edaaa 100644
--- a/sbin/zfsbootcfg/zfsbootcfg.8
+++ b/sbin/zfsbootcfg/zfsbootcfg.8
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 24, 2017
+.Dd July 22, 2020
 .Dt ZFSBOOTCFG 8
 .Os
 .Sh NAME
@@ -33,39 +33,88 @@
 .Sh SYNOPSIS
 .Nm
 .Ao Ar options Ac
+.Nm
+.Op Fl n Ar name
+.Op Fl k Ar key
+.Op Fl p
+.Op Fl t Ar type
+.Op Fl v Ar value
+.Op Fl z Ar pool
+.Nm
 .Sh DESCRIPTION
 .Nm
 is used to set
 .Xr boot.config 5 Ns -style
 options to be used by
-.Xr zfsboot 8
-or
+.Xr zfsboot 8 ,
 .Xr gptzfsboot 8
+or
+.Xr loader 8
 the next time the machine is booted.
 Once
 .Xr zfsboot 8
 or
 .Xr gptzfsboot 8
+or
+.Xr loader 8
 reads the information, it is deleted.
 If booting fails, the machine automatically reverts to the previous
 boot configuration.
-The information is stored in a special reserved area of a ZFS pool.
-.Xr zfsboot 8
-or
-.Xr gptzfsboot 8
-read the boot option information from the first disk found in the first
-ZFS pool found.
+The information is stored in a special boot environment area of a ZFS pool.
+.Pp
+If used without arguments,
+.Nm
+will output the current boot configuration, if set.
+.Pp
+The following options are supported by
+.Nm :
+.Bl -tag -width indent
+.It Fl k Ar key
+Define key for
+.Ao key , value Ac
+pair.
+.It Fl n Ar name
+Update nvlist
+.Ar name .
+.It Fl p
+Print all information stored in ZFS pool bootenv area.
+.It Fl t Ar type
+Set type of
+.Ar value
+used in
+.Ao key , value Ac
+pair.
+Currently supported types are:
+.Bl -tag -width indent -compact
+.It Ar DATA_TYPE_BYTE
+.It Ar DATA_TYPE_INT8
+.It Ar DATA_TYPE_UINT8
+.It Ar DATA_TYPE_INT16
+.It Ar DATA_TYPE_UINT16
+.It Ar DATA_TYPE_INT32
+.It Ar DATA_TYPE_UINT32
+.It Ar DATA_TYPE_INT64
+.It Ar DATA_TYPE_UINT64
+.It Ar DATA_TYPE_BOOLEAN_VALUE
+.It Ar DATA_TYPE_STRING
+.El
+.Pp
+If not specified, the default is
+.Ar DATA_TYPE_STRING .
+.It Fl v Ar value
+Define value for
+.Ao key , value Ac
+pair.
+.It Fl z Ar pool
+Operate on
+.Ar pool .
+.El
 .Sh ENVIRONMENT
-.Bl -tag -width vfs.zfs.boot.primary_pool -compact
-.It Ev vfs.zfs.boot.primary_pool
+.Bl -tag -width vfs.root.mountfrom -compact
+.It Ev vfs.root.mountfrom
 The
 .Xr kenv 1
 variable that identifies a pool for which the options are written.
-.It Ev vfs.zfs.boot.primary_vdev
-The
-.Xr kenv 1
-variable that identifies a disk within the pool where the options
-are written.
 .El
 .Sh EXAMPLES
 Try to boot to a new
@@ -81,7 +130,9 @@ To clear the boot options:
 .Dl "zfsbootcfg """"
 .Sh SEE ALSO
 .Xr boot.config 5 ,
+.Xr bectl 8 ,
 .Xr gptzfsboot 8 ,
+.Xr loader 8 ,
 .Xr zfsboot 8
 .Sh HISTORY
 .Nm
@@ -90,23 +141,3 @@ appeared in
 .Sh AUTHORS
 This manual page was written by
 .An Andriy Gapon Aq Mt avg@FreeBSD.org .
-.Sh CAVEATS
-At the moment,
-.Nm
-uses the
-.Ev vfs.zfs.boot.primary_pool
-and
-.Ev vfs.zfs.boot.primary_vdev
-.Xr kenv 1
-variables to determine a ZFS pool and a disk in it where the options
-are to be stored.
-The variables are set by the ZFS boot chain, so there is an assumption
-that the same boot disk is going to be used for the next reboot.
-There is no
-.Nm
-option to specify a different pool or a different disk.
-.Pp
-.Nm
-should be extended to install new
-.Xr zfsboot 8
-blocks in a ZFS pool.
diff --git a/sbin/zfsbootcfg/zfsbootcfg.c b/sbin/zfsbootcfg/zfsbootcfg.c
index 4ff1a35e2ec7..f4b2eeabcc3b 100644
--- a/sbin/zfsbootcfg/zfsbootcfg.c
+++ b/sbin/zfsbootcfg/zfsbootcfg.c
@@ -32,115 +32,257 @@ __FBSDID("$FreeBSD$");
 #include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdbool.h>
 #include <string.h>
 #include <kenv.h>
+#include <unistd.h>
 
-#include <libzfs.h>
+#include <libzfsbootenv.h>
 
-/* Keep in sync with zfsboot.c. */
-#define MAX_COMMAND_LEN	512
+#ifndef ZFS_MAXNAMELEN
+#define	ZFS_MAXNAMELEN	256
+#endif
 
-int
-install_bootonce(libzfs_handle_t *hdl, uint64_t pool_guid, nvlist_t *nv,
-    const char * const data)
+static int
+add_pair(const char *name, const char *nvlist, const char *key,
+    const char *type, const char *value)
 {
-	nvlist_t **child;
-	uint_t children = 0;
-	uint64_t guid;
+	void *data, *nv;
+	size_t size;
 	int rv;
+	char *end;
 
-	(void) nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_CHILDREN, &child,
-	    &children);
+	rv = lzbe_nvlist_get(name, nvlist, &nv);
+	if (rv != 0)
+		return (rv);
 
-	for (int c = 0; c < children; c++) {
-		rv = install_bootonce(hdl, pool_guid, child[c], data);
-	}
+	data = NULL;
+	rv = EINVAL;
+	if (strcmp(type, "DATA_TYPE_STRING") == 0) {
+		data = __DECONST(void *, value);
+		size = strlen(data) + 1;
+		rv = lzbe_add_pair(nv, key, type, data, size);
+	} else if (strcmp(type, "DATA_TYPE_UINT64") == 0) {
+		uint64_t v;
 
-	if (children > 0)
-		return (rv);
+		v = strtoull(value, &end, 0);
+		if (errno != 0 || *end != '\0')
+			goto done;
+		size = sizeof (v);
+		rv = lzbe_add_pair(nv, key, type, &v, size);
+	} else if (strcmp(type, "DATA_TYPE_INT64") == 0) {
+		int64_t v;
 
-	if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0) {
-		perror("can't get vdev guid");
-		return (1);
-	}
-	if (zpool_nextboot(hdl, pool_guid, guid, data) != 0) {
-		perror("ZFS_IOC_NEXTBOOT failed");
-		return (1);
+		v = strtoll(value, &end, 0);
+		if (errno != 0 || *end != '\0')
+			goto done;
+		size = sizeof (v);
+		rv = lzbe_add_pair(nv, key, type, &v, size);
+	} else if (strcmp(type, "DATA_TYPE_UINT32") == 0) {
+		uint32_t v;
+
+		v = strtoul(value, &end, 0);
+		if (errno != 0 || *end != '\0')
+			goto done;
+		size = sizeof (v);
+		rv = lzbe_add_pair(nv, key, type, &v, size);
+	} else if (strcmp(type, "DATA_TYPE_INT32") == 0) {
+		int32_t v;
+
+		v = strtol(value, &end, 0);
+		if (errno != 0 || *end != '\0')
+			goto done;
+		size = sizeof (v);
+		rv = lzbe_add_pair(nv, key, type, &v, size);
+	} else if (strcmp(type, "DATA_TYPE_UINT16") == 0) {
+		uint16_t v;
+
+		v = strtoul(value, &end, 0);
+		if (errno != 0 || *end != '\0')
+			goto done;
+		size = sizeof (v);
+		rv = lzbe_add_pair(nv, key, type, &v, size);
+	} else if (strcmp(type, "DATA_TYPE_INT16") == 0) {
+		int16_t v;
+
+		v = strtol(value, &end, 0);
+		if (errno != 0 || *end != '\0')
+			goto done;
+		size = sizeof (v);
+		rv = lzbe_add_pair(nv, key, type, &v, size);
+	} else if (strcmp(type, "DATA_TYPE_UINT8") == 0) {
+		uint8_t v;
+
+		v = strtoul(value, &end, 0);
+		if (errno != 0 || *end != '\0')
+			goto done;
+		size = sizeof (v);
+		rv = lzbe_add_pair(nv, key, type, &v, size);
+	} else if (strcmp(type, "DATA_TYPE_INT8") == 0) {
+		int8_t v;
+
+		v = strtol(value, &end, 0);
+		if (errno != 0 || *end != '\0')
+			goto done;
+		size = sizeof (v);
+		rv = lzbe_add_pair(nv, key, type, &v, size);
+	} else if (strcmp(type, "DATA_TYPE_BYTE") == 0) {
+		uint8_t v;
+
+		v = strtoul(value, &end, 0);
+		if (errno != 0 || *end != '\0')
+			goto done;
+		size = sizeof (v);
+		rv = lzbe_add_pair(nv, key, type, &v, size);
+	} else if (strcmp(type, "DATA_TYPE_BOOLEAN_VALUE") == 0) {
+		int32_t v;
+
+		v = strtol(value, &end, 0);
+		if (errno != 0 || *end != '\0') {
+			if (strcasecmp(value, "YES") == 0)
+				v = 1;
+			else if (strcasecmp(value, "NO") == 0)
+				v = 0;
+			if (strcasecmp(value, "true") == 0)
+				v = 1;
+			else if (strcasecmp(value, "false") == 0)
+				v = 0;
+			else goto done;
+		}
+		size = sizeof (v);
+		rv = lzbe_add_pair(nv, key, type, &v, size);
 	}
-	return (0);
+
+	if (rv == 0)
+		rv = lzbe_nvlist_set(name, nvlist, nv);
+
+done:
+	lzbe_nvlist_free(nv);
+	return (rv);
 }
 
-int main(int argc, const char * const *argv)
+static int
+delete_pair(const char *name, const char *nvlist, const char *key)
 {
-	char buf[32], *name;
-	libzfs_handle_t *hdl;
-	zpool_handle_t *zphdl;
-	uint64_t pool_guid;
-	nvlist_t *nv, *config;
+	void *nv;
 	int rv;
-	int len;
 
-	if (argc != 2) {
-		fprintf(stderr, "usage: zfsbootcfg <boot.config(5) options>\n");
-		return (1);
+	rv = lzbe_nvlist_get(name, nvlist, &nv);
+	if (rv == 0) {
+		rv = lzbe_remove_pair(nv, key);
 	}
+	if (rv == 0)
+		rv = lzbe_nvlist_set(name, nvlist, nv);
 
-	len = strlen(argv[1]);
-	if (len >= MAX_COMMAND_LEN) {
-		fprintf(stderr, "options string is too long\n");
-		return (1);
-	}
+	lzbe_nvlist_free(nv);
+	return (rv);
+}
 
-	if (kenv(KENV_GET, "vfs.root.mountfrom", buf, sizeof(buf)) <= 0) {
-		perror("can't get vfs.root.mountfrom");
-		return (1);
-	}
+/*
+ * Usage: zfsbootcfg [-z pool] [-d key] [-k key -t type -v value] [-p]
+ *	zfsbootcfg [-z pool] -n nvlist [-d key] [-k key -t type -v value] [-p]
+ *
+ * if nvlist is set, we will update nvlist in bootenv.
+ * if nvlist is not set, we update pairs in bootenv.
+ */
+int
+main(int argc, char * const *argv)
+{
+	char buf[ZFS_MAXNAMELEN], *name;
+	const char *key, *value, *type, *nvlist;
+	int rv;
+	bool print, delete;
 
-	if (strncmp(buf, "zfs:", 4) == 0) {
-		name = strchr(buf + 4, '/');
-		if (name != NULL)
-			*name = '\0';
-		name = buf + 4;
-	} else {
-		perror("not a zfs root");
-		return (1);
-	}
-		
-	if ((hdl = libzfs_init()) == NULL) {
-		(void) fprintf(stderr, "internal error: failed to "
-		    "initialize ZFS library\n");
-		return (1);
+	nvlist = NULL;
+	name = NULL;
+	key = NULL;
+	type = NULL;
+	value = NULL;
+	print = delete = false;
+	while ((rv = getopt(argc, argv, "d:k:n:pt:v:z:")) != -1) {
+		switch (rv) {
+		case 'd':
+			delete = true;
+			key = optarg;
+			break;
+		case 'k':
+			key = optarg;
+			break;
+		case 'n':
+			nvlist = optarg;
+			break;
+		case 'p':
+			print = true;
+			break;
+		case 't':
+			type = optarg;
+			break;
+		case 'v':
+			value = optarg;
+			break;
+		case 'z':
+			name = optarg;
+			break;
+		}
 	}
 
-	zphdl = zpool_open(hdl, name);
-	if (zphdl == NULL) {
-		perror("can't open pool");
-		libzfs_fini(hdl);
+	argc -= optind;
+	argv += optind;
+
+	if (argc == 1)
+		value = argv[0];
+
+	if (argc > 1) {
+		fprintf(stderr, "usage: zfsbootcfg <boot.config(5) options>\n");
 		return (1);
 	}
 
-	pool_guid = zpool_get_prop_int(zphdl, ZPOOL_PROP_GUID, NULL);
+	if (name == NULL) {
+		rv = kenv(KENV_GET, "vfs.root.mountfrom", buf, sizeof(buf));
+		if (rv <= 0) {
+			perror("can't get vfs.root.mountfrom");
+			return (1);
+		}
 
-	config = zpool_get_config(zphdl, NULL);
-	if (config == NULL) {
-		perror("can't get pool config");
-		zpool_close(zphdl);
-		libzfs_fini(hdl);
-		return (1);
+		if (strncmp(buf, "zfs:", 4) == 0) {
+			name = strchr(buf + 4, '/');
+			if (name != NULL)
+				*name = '\0';
+			name = buf + 4;
+		} else {
+			perror("not a zfs root");
+			return (1);
+		}
 	}
 
-	if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, &nv) != 0) {
-		perror("failed to get vdev tree");
-		zpool_close(zphdl);
-		libzfs_fini(hdl);
-		return (1);
+	rv = 0;
+	if (key != NULL || value != NULL) {
+		if (type == NULL)
+			type = "DATA_TYPE_STRING";
+
+		if (delete)
+			rv = delete_pair(name, nvlist, key);
+		else if (key == NULL || strcmp(key, "command") == 0)
+			rv = lzbe_set_boot_device(name, lzbe_add, value);
+		else
+			rv = add_pair(name, nvlist, key, type, value);
+
+		if (rv == 0)
+			printf("zfs bootenv is successfully written\n");
+		else
+			printf("error: %d\n", rv);
+	} else if (!print) {
+		char *ptr;
+
+		if (lzbe_get_boot_device(name, &ptr) == 0) {
+			printf("zfs:%s:\n", ptr);
+			free(ptr);
+		}
 	}
 
-	rv = install_bootonce(hdl, pool_guid, nv, argv[1]);
+	if (print) {
+		rv = lzbe_bootenv_print(name, nvlist, stdout);
+	}
 
-	zpool_close(zphdl);
-	libzfs_fini(hdl);
-	if (rv == 0)
-		printf("zfs next boot options are successfully written\n");
 	return (rv);
 }