freebsd-version(1): Add -j flag to support jails

Make freebsd-version(1) support jails by adding the -j flag which takes
a jail jid or name as an argument. As with other options, -j
flags stack and display in the order requested.

Reviewed by:	bcr (manpages), kevans
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D25705

bin/freebsd-version/freebsd-version.1

@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 14, 2017
+.Dd October 1, 2021
 .Dt FREEBSD-VERSION 1
 .Os
 .Sh NAME
@@ -34,6 +34,7 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl kru
+.Op Fl j Ar jail
 .Sh DESCRIPTION
 The
 .Nm
@@ -60,12 +61,20 @@ Print the version and patch level of the installed userland.
 These are hardcoded into
 .Nm
 during the build.
+.It Fl j Ar jail
+Print the version and patch level of the installed userland in the
+given jail specified by
+.Va jid
+or
+.Va name .
+This option can be specified multiple times.
 .El
 .Pp
 If several of the above options are specified,
 .Nm
 will print the installed kernel version first, then the running kernel
-version, and finally the userland version, on separate lines.
+version, next the userland version, and finally the userland version
+of the specified jails, on separate lines.
 If neither is specified, it will print the userland version only.
 .Sh IMPLEMENTATION NOTES
 The

bin/freebsd-version/freebsd-version.sh.in

@@ -84,11 +84,20 @@ userland_version() {
 	echo $USERLAND_VERSION
 }
 
+#
+# Print the hardcoded userland version of a jail.
+#
+jail_version() {
+	for i in $jail; do
+		jexec -- $i freebsd-version
+	done
+}
+
 #
 # Print a usage string and exit.
 #
 usage() {
-	echo "usage: $progname [-kru]" >&2
+	echo "usage: $progname [-kru] [-j jail]" >&2
 	exit 1
 }
 
@@ -97,7 +106,8 @@ usage() {
 #
 main() {
 	# parse command-line arguments
-	while getopts "kru" option ; do
+	local OPTIND=1 OPTARG option
+	while getopts "kruj:" option ; do
 		case $option in
 		k)
 			opt_k=1
@@ -108,6 +118,14 @@ main() {
 		u)
 			opt_u=1
 			;;
+		j)
+			if [ $opt_j ] ; then
+				jail="$jail $OPTARG"
+			else
+				opt_j=1
+				jail="$OPTARG"
+			fi
+			;;
 		*)
 			usage
 			;;
@@ -118,7 +136,7 @@ main() {
 	fi
 
 	# default is -u
-	if [ $((opt_k + opt_r + opt_u)) -eq 0 ] ; then
+	if [ $((opt_k + opt_r + opt_u + opt_j)) -eq 0 ] ; then
 		opt_u=1
 	fi
 
@@ -136,6 +154,11 @@ main() {
 	if [ $opt_u ] ; then
 		userland_version
 	fi
+
+	# print jail version
+	if [ $opt_j ] ; then
+		jail_version
+	fi
 }
 
 main "$@"