Add two new rc.conf options: tmpmfs_flags and varmfs_flags.

These can be used to pass extra options to the mdmfs(8) utility,
to customize the finer details of the md file system creation
(i.e. to turn on/off softupdates, to specify a default owner for md
filesystem, etc).

Use these two new flags to mount tmpmfs and varmfs without
softupdates, since it doesn't make much sense to use SU on
malloc-backed file systems.

Reviewed by:	mtm
Inspired by:	J. D. Bronson, jbronson at wixb dot com

etc/defaults/rc.conf

@@ -40,8 +40,10 @@ pccard_ether_delay="5"	# Delay before trying to start dhclient in pccard_ether
 removable_interfaces=""	# Removable network interfaces for /etc/pccard_ether.
 tmpmfs="AUTO"		# Set to YES to always create an mfs /tmp, NO to never
 tmpsize="20m"		# Size of mfs /tmp if created
+tmpmfs_flags="-S -o noexec,nosuid,nodev" # Extra mdmfs options for the mfs /tmp
 varmfs="AUTO"		# Set to YES to always create an mfs /var, NO to never
 varsize="32m"		# Size of mfs /var if created
+varmfs_flags="-S"	# Extra mount options for the mfs /var
 populate_var="AUTO"	# Set to YES to always (re)populate /var, NO to never
 local_startup="/usr/local/etc/rc.d /usr/X11R6/etc/rc.d" # startup script dirs.
 script_name_sep=" "	# Change if your startup scripts' names contain spaces

etc/rc.d/tmp

@@ -42,7 +42,7 @@ load_rc_config $name
 #
 case "${tmpmfs}" in
 [Yy][Ee][Ss])
-	mount_md ${tmpsize} /tmp
+	mount_md ${tmpsize} /tmp "${tmpmfs_flags}"
 	chmod 01777 /tmp
 	;;
 [Nn][Oo])
@@ -56,7 +56,7 @@ case "${tmpmfs}" in
 			echo "dropping into shell, ^D to continue anyway."
 			/bin/sh
 		else
-			mount_md ${tmpsize} /tmp
+			mount_md ${tmpsize} /tmp "${tmpmfs_flags}"
 			chmod 01777 /tmp
 		fi
 	fi

etc/rc.d/var

@@ -61,7 +61,7 @@ _populate_var()
 #
 case "${varmfs}" in
 [Yy][Ee][Ss])
-	mount_md ${varsize} /var
+	mount_md ${varsize} /var "${varmfs_flags}"
 	;;
 [Nn][Oo])
 	;;
@@ -69,7 +69,7 @@ case "${varmfs}" in
 	if (/bin/mkdir -p /var/.diskless 2> /dev/null); then
 		rmdir /var/.diskless
 	else
-		mount_md ${varsize} /var
+		mount_md ${varsize} /var "${varmfs_flags}"
 	fi
 esac
 

etc/rc.subr

@@ -1289,12 +1289,12 @@ devfs_mount_jail()
 # as close as possible between 5-current and 4-stable.
 #   $1 = size
 #   $2 = mount point
-#   $3 = (optional) bytes-per-inode
+#   $3 = (optional) extra mdmfs flags
 mount_md() {
 	if [ -n "$3" ]; then
-		bpi="-i $3"
+		flags="$3"
 	fi
-	/sbin/mdmfs $bpi -s $1 -M md $2
+	/sbin/mdmfs $flags -s $1 -M md $2
 }
 
 fi

share/man/man5/rc.conf.5

@@ -240,6 +240,22 @@ is not writable.
 Controls the size of a created
 .Pa /tmp
 memory file system.
+.It Va tmpmfs_flags
+Extra options passed to the
+.Xr mdmfs 8
+utility when the memory file system for
+.Pa /tmp
+is created.
+The default is
+.Dq Li -S -o noexec,nosuid,nodev ,
+which inhibits the use of softupdates on
+.Pa /tmp
+to waste as little space as possible and mounts the memory file system
+.Dq Li noexec,nosuid,nodev .
+See
+.Xr mdmfs 8
+for other options you can use in
+.Li tmpmfs_flags .
 .It Va varmfs
 Controls the creation of a
 .Pa /var
@@ -255,6 +271,21 @@ is not writable.
 Controls the size of a created
 .Pa /var
 memory file system.
+.It Va varmfs_flags
+Extra options passed to the
+.Xr mdmfs 8
+utility when the memory file system for
+.Pa /var
+is created.
+The default is
+.Dq Li -S ,
+which inhibits the use of softupdates on
+.Pa /var
+to waste as little space as possible.
+See
+.Xr mdmfs 8
+for other options you can use in
+.Li varmfs_flags .
 .It Va populate_var
 Controls the automatic population of the
 .Pa /var
@@ -3109,6 +3140,7 @@ device and the mount point will be changed.
 .Xr kldxref 8 ,
 .Xr lpd 8 ,
 .Xr mdconfig 8 ,
+.Xr mdmfs 8 ,
 .Xr mountd 8 ,
 .Xr moused 8 ,
 .Xr mrouted 8 ,