adduser(8): support creation of ZFS dataset

On systems utilizing ZFS, default to creating a ZFS dataset for a new
user's home directory if the parent directory resides on a ZFS dataset.
Also add a flag that disables this behavior if the administrator
explicitly does not want it.

usr.sbin/adduser/adduser.8

@@ -32,7 +32,7 @@
 .Nd command for adding new users
 .Sh SYNOPSIS
 .Nm
-.Op Fl CDENShq
+.Op Fl CDENSZhq
 .Op Fl G Ar groups
 .Op Fl L Ar login_class
 .Op Fl M Ar mode
@@ -52,6 +52,10 @@ utility is a shell script, implemented around the
 command, for adding new users.
 It creates passwd/group entries, a home directory,
 copies dotfiles and sends the new user a welcome message.
+On systems where the parent of home directory is a ZFS dataset,
+.Nm
+will create the home directory as a ZFS dataset by default,
+unless the system administrator specified otherwise.
 It supports two modes of operation.
 It may be used interactively
 at the command line to add one user at a time, or it may be directed
@@ -295,6 +299,8 @@ In addition, it will be available for inclusion in the message file in the
 .Va randompass
 variable.
 .El
+.It Fl Z
+Do not attempt to create ZFS home dataset.
 .El
 .Sh FORMAT
 When the

usr.sbin/adduser/adduser.conf.5

@@ -171,6 +171,8 @@ The default information to be held in the GECOS field of
 .It Va uidstart
 The default user ID setting.
 This must be a number above 1000 and fewer than 65534.
+.It Va Zflag
+Do not attempt to create ZFS home dataset.
 .El
 .Sh EXAMPLES
 The following is an example

usr.sbin/adduser/adduser.sh

@@ -84,6 +84,7 @@ show_usage() {
 	echo "  -L		login class of the user"
 	echo "  -M		file permission for home directory"
 	echo "  -N		do not read configuration file"
+	echo "  -Z		do not attempt to create ZFS home dataset"
 	echo "  -S		a nonexistent shell is not an error"
 	echo "  -d		home directory"
 	echo "  -f		file from which input will be received"
@@ -202,6 +203,7 @@ save_config() {
 	echo "msgfile=$msgfile"		>> ${ADDUSERCONF}
 	echo "disableflag=$disableflag" >> ${ADDUSERCONF}
 	echo "uidstart=$uidstart"       >> ${ADDUSERCONF}
+	echo "Zflag=$Zflag"       >> ${ADDUSERCONF}
 }
 
 # add_user
@@ -283,6 +285,15 @@ add_user() {
 		;;
 	esac
 
+	# create ZFS dataset before home directory is created with pw
+	if [ -z "$Zflag" ]; then
+		create_zfs_dataset
+		if [ "$?" -ne 0 ]; then
+			err "There was an error adding user ($username)."
+			return 1
+		fi
+	fi
+
 	_pwcmd="$_upasswd ${PWCMD} useradd $_uid $_name $_group $_grouplist $_comment"
 	_pwcmd="$_pwcmd $_shell $_class $_home $_dotdir $_passwdmethod $_passwd"
 	_pwcmd="$_pwcmd $_expire $_pwexpire"
@@ -306,6 +317,11 @@ add_user() {
 		fi
 	fi
 
+	# give newly created user permissions to their home zfs dataset
+	if [ -z "$Zflag" ]; then
+		set_zfs_perms
+	fi
+
 	_line=
 	_owner=
 	_perms=
@@ -479,6 +495,20 @@ get_homeperm() {
 	fi
 }
 
+# get_zfs_home
+#	Determine if homeprefix is located on a ZFS filesystem and if
+#	so, enable ZFS home dataset creation.
+#
+get_zfs_home() {
+	zfs_homeprefix=`${ZFSCMD} list -Ho name "${homeprefix}" 2>/dev/null`
+	if [ "$?" -ne 0 ]; then
+		Zflag=yes
+	elif [ -z "${zfs_homeprefix}" ]; then
+		Zflag=yes
+	fi
+	zhome="${zfs_homeprefix}/${username}"
+}
+
 # get_uid
 #	Reads a numeric userid in an interactive or batch session. Automatically
 #	allocates one if it is not specified.
@@ -613,6 +643,30 @@ get_password() {
 	fi
 }
 
+# create_zfs_dataset
+#   Create ZFS dataset owned by the user that was just added.
+#
+create_zfs_dataset() {
+	${ZFSCMD} create "${zhome}"
+	if [ "$?" -ne 0 ]; then
+		err "There was an error creating ZFS dataset (${zhome})."
+		return 1
+	else
+		info "Successfully created ZFS dataset (${zhome})."
+	fi
+}
+
+# set_zfs_perms
+#   Give new user ownership of newly created zfs dataset.
+#
+set_zfs_perms() {
+	${ZFSCMD} allow "${username}" create,destroy,mount,snapshot "${zhome}"
+	if [ "$?" -ne 0 ]; then
+		err "There was an error setting permissions on ZFS dataset (${zhome})."
+		return 1
+	fi
+}
+
 # input_from_file
 #	Reads a line of account information from standard input and
 #	adds it to the user database.
@@ -632,6 +686,7 @@ input_from_file() {
 			get_class
 			get_shell
 			get_homedir
+			get_zfs_home
 			get_homeperm
 			get_password
 			get_expire_dates
@@ -704,6 +759,7 @@ input_interactive() {
 	get_shell
 	get_homedir
 	get_homeperm
+	get_zfs_home
 
 	while : ; do
 		echo -n "Use password-based authentication? [$_usepass]: "
@@ -787,12 +843,12 @@ input_interactive() {
 		esac
 		break
 	done
-	
+
 	# Display the information we have so far and prompt to
 	# commit it.
 	#
 	_disable=${disableflag:-"no"}
-	[ -z "$configflag" ] && printf "%-10s : %s\n" Username $username
+	[ -z "$configflag" ] && printf "%-11s : %s\n" Username $username
 	case $passwdtype in
 	yes)
 		_pass='*****'
@@ -807,16 +863,17 @@ input_interactive() {
 		_pass='<random>'
 		;;
 	esac
-	[ -z "$configflag" ] && printf "%-10s : %s\n" "Password" "$_pass"
-	[ -n "$configflag" ] && printf "%-10s : %s\n" "Pass Type" "$passwdtype"
-	[ -z "$configflag" ] && printf "%-10s : %s\n" "Full Name" "$ugecos"
-	[ -z "$configflag" ] && printf "%-10s : %s\n" "Uid" "$uuid"
-	printf "%-10s : %s\n" "Class" "$uclass"
-	printf "%-10s : %s %s\n" "Groups" "${ulogingroup:-$username}" "$ugroups"
-	printf "%-10s : %s\n" "Home" "$uhome"
-	printf "%-10s : %s\n" "Home Mode" "$uhomeperm"
-	printf "%-10s : %s\n" "Shell" "$ushell"
-	printf "%-10s : %s\n" "Locked" "$_disable"
+	[ -z "$configflag" ] && printf "%-11s : %s\n" "Password" "$_pass"
+	[ -n "$configflag" ] && printf "%-11s : %s\n" "Pass Type" "$passwdtype"
+	[ -z "$configflag" ] && printf "%-11s : %s\n" "Full Name" "$ugecos"
+	[ -z "$configflag" ] && printf "%-11s : %s\n" "Uid" "$uuid"
+	[ -z "$Zflag" -a -z "$configflag" ] && printf "%-11s : %s\n" "ZFS dataset" "${zhome}"
+	printf "%-11s : %s\n" "Class" "$uclass"
+	printf "%-11s : %s %s\n" "Groups" "${ulogingroup:-$username}" "$ugroups"
+	printf "%-11s : %s\n" "Home" "$uhome"
+	printf "%-11s : %s\n" "Home Mode" "$uhomeperm"
+	printf "%-11s : %s\n" "Shell" "$ushell"
+	printf "%-11s : %s\n" "Locked" "$_disable"
 	while : ; do
 		echo -n "OK? (yes/no) [$_all_ok]: "
 		read _input
@@ -852,6 +909,7 @@ NOLOGIN="nologin"
 NOLOGIN_PATH="/usr/sbin/nologin"
 GREPCMD="/usr/bin/grep"
 DATECMD="/bin/date"
+ZFSCMD="/sbin/zfs"
 
 # Set default values
 #
@@ -880,6 +938,7 @@ infile=
 disableflag=
 Dflag=
 Sflag=
+Zflag=
 readconfig="yes"
 homeprefix="/home"
 randompass=
@@ -1014,6 +1073,10 @@ for _switch ; do
 		uidstart=$2
 		shift; shift
 		;;
+	-Z)
+		Zflag=yes
+		shift
+		;;
 	esac
 done