Add JSON output support to channel programs

The changes piggyback JSON output support on top of channel programs 
(#6558).  This way the JSON output support is targeted to scripting 
use cases and is easily maintainable since it really only touches 
one function (zfs_do_channel_program()).

This patch ports Joyent's JSON nvlist library from illumos to enable 
easy JSON printing of channel program output nvlist.  To keep the 
delta small I also took advantage of the fact that printing in
zfs_do_channel_program() was almost always done before exiting 
the program.

Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alek Pinchuk <apinchuk@datto.com>
Closes #7281

tests/zfs-tests/tests/functional/cli_root/Makefile.am

@@ -16,6 +16,7 @@ SUBDIRS = \
 	zfs_inherit \
 	zfs_load-key \
 	zfs_mount \
+	zfs_program \
 	zfs_promote \
 	zfs_property \
 	zfs_receive \

tests/zfs-tests/tests/functional/cli_root/zfs_program/Makefile.am

@@ -0,0 +1,5 @@
+pkgdatadir = $(datadir)/@PACKAGE@/zfs-tests/tests/functional/cli_root/zfs_program
+dist_pkgdata_SCRIPTS = \
+	setup.ksh \
+	cleanup.ksh \
+	zfs_program_json.ksh

tests/zfs-tests/tests/functional/cli_root/zfs_program/cleanup.ksh

@@ -0,0 +1,30 @@
+#!/bin/ksh -p
+#
+# 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.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+default_cleanup

tests/zfs-tests/tests/functional/cli_root/zfs_program/setup.ksh

@@ -0,0 +1,32 @@
+#!/bin/ksh -p
+#
+# 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.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+DISK=${DISKS%% *}
+
+default_setup $DISK

tests/zfs-tests/tests/functional/cli_root/zfs_program/zfs_program_json.ksh

@@ -0,0 +1,132 @@
+#!/bin/ksh -p
+#
+# CDDL HEADER START
+#
+# This file and its contents are supplied under the terms of the
+# Common Development and Distribution License ("CDDL"), version 1.0.
+# You may only use this file in accordance with the terms of version
+# 1.0 of the CDDL.
+#
+# A full copy of the text of the CDDL should have accompanied this
+# source.  A copy is of the CDDL is also available via the Internet
+# at http://www.illumos.org/license/CDDL.
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2018 Datto Inc.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+#
+# STRATEGY:
+#	1. Compare JSON output formatting for a channel program to template
+#	2. Using bad command line option (-Z) gives correct error output
+#
+
+verify_runnable "both"
+
+function cleanup
+{
+	log_must zfs destroy $TESTDS
+	return 0
+}
+log_onexit cleanup
+
+log_assert "Channel programs output valid JSON"
+
+TESTDS="$TESTPOOL/zcp-json"
+log_must zfs create $TESTDS
+
+TESTZCP="/$TESTDS/zfs_rlist.zcp"
+cat > "$TESTZCP" << EOF
+	succeeded = {}
+	failed = {}
+
+	function list_recursive(root, prop)
+		for child in zfs.list.children(root) do
+			list_recursive(child, prop)
+		end
+		val, src  = zfs.get_prop(root, prop)
+		if (val == nil) then
+			failed[root] = val
+		else
+			succeeded[root] = val
+		end
+	end
+
+	args = ...
+
+	argv = args["argv"]
+
+	list_recursive(argv[1], argv[2])
+
+	results = {}
+	results["succeeded"] = succeeded
+	results["failed"] = failed
+	return results
+EOF
+
+# 1. Compare JSON output formatting for a channel program to template
+typeset -a pos_cmds=("recordsize" "type")
+typeset -a pos_cmds_out=(
+"{
+    \"return\": {
+        \"failed\": {},
+        \"succeeded\": {
+            \"$TESTDS\": 131072
+        }
+    }
+}"
+"{
+    \"return\": {
+        \"failed\": {},
+        \"succeeded\": {
+            \"$TESTDS\": \"filesystem\"
+        }
+    }
+}")
+typeset -i cnt=0
+typeset cmd
+for cmd in ${pos_cmds[@]}; do
+	log_must zfs program $TESTPOOL $TESTZCP $TESTDS $cmd 2>&1
+	log_must zfs program $TESTPOOL -j $TESTZCP $TESTDS $cmd 2>&1
+	# json.tool is needed to guarantee consistent ordering of fields
+	# sed is needed to trim trailing space in CentOS 6's json.tool output
+	OUTPUT=$(zfs program $TESTPOOL -j $TESTZCP $TESTDS $cmd 2>&1 | python -m json.tool | sed 's/[[:space:]]*$//')
+	if [ "$OUTPUT" != "${pos_cmds_out[$cnt]}" ]; then
+		log_note "Got     :$OUTPUT"
+		log_note "Expected:${pos_cmds_out[$cnt]}"
+		log_fail "Unexpected channel program output";
+	fi
+	cnt=$((cnt + 1))
+done
+
+# 2. Using bad command line option (-Z) gives correct error output
+typeset -a neg_cmds=("-Z")
+typeset -a neg_cmds_out=(
+"invalid option 'Z'
+usage:
+	program [-jn] [-t <instruction limit>] [-m <memory limit (b)>] <pool> <program file> [lua args...]
+
+For the property list, run: zfs set|get
+
+For the delegated permission list, run: zfs allow|unallow")
+cnt=0
+for cmd in ${neg_cmds[@]}; do
+	log_mustnot zfs program $TESTPOOL $TESTZCP $TESTDS $cmd 2>&1
+	log_mustnot zfs program $TESTPOOL -j $TESTZCP $TESTDS $cmd 2>&1
+	OUTPUT=$(zfs program $TESTPOOL -j $TESTZCP $TESTDS $cmd 2>&1)
+	if [ "$OUTPUT" != "${neg_cmds_out[$cnt]}" ]; then
+		log_note "Got     :$OUTPUT"
+		log_note "Expected:${neg_cmds_out[$cnt]}"
+		log_fail "Unexpected channel program error output";
+	fi
+	cnt=$((cnt + 1))
+done
+
+log_pass "Channel programs output valid JSON"