New image framework generation

The CD now boots directly from the ISO 9660 filesystem instead of using
MBR partitioning with Minix file systems. This saves some space on the
CD and reduces memory requirements by some unknown amount as the root
ramdisk is completely eliminated.

The x86 hard drive image creation is also rewritten in the same
fashion.

The setup is modified to be more NetBSD-like (unpacking sets
tarballs instead of blindly copying the CD contents). Splitting MINIX
into sets is done in another commit due to it being a nightmare to
rebase.

Since MINIX lacks union mounts for now, a bunch of ramdisks are
generated at run-time to make parts of the filesystem writeable for the
CD. This solution isn't ideal, but it's enough for an installation CD.

Change-Id: Icbd9cca4dafebf7b42c345b107a17679a622d5cd

etc/rc

@@ -1,5 +1,8 @@
 # /etc/rc - System startup script run by init before going multiuser.
 
+# Are we booting from CD?
+bootcd="`/bin/sysenv bootcd`"
+
 exec >/dev/log
 exec 2>/dev/log
 exec </dev/null
@@ -64,7 +67,7 @@ edit()
     if [ ! -x $binlocation ]
     then	binlocation=/sbin/$service
     fi
-    service $opt edit $binlocation -label $service "$@" 
+    service $opt edit $binlocation -label $service "$@"
 }
 
 while getopts 'saf' opt
@@ -87,6 +90,11 @@ esac
 
 case $action in
 autoboot|start)
+    # If booting from CD, we want some directories to be ramdisks
+    if [ ! -z "$bootcd" ]
+    then
+	. /etc/rc.cd
+    fi
 
     # National keyboard?
     test -f /etc/keymap && loadkeys /etc/keymap
@@ -106,7 +114,8 @@ autoboot|start)
     # Set timezone.
     export TZ=GMT0
     if [ -f "$RC_TZ" ]
-    then . "$RC_TZ"
+    then
+         . "$RC_TZ"
     fi
 
     # Start real time clock driver & set system time, otherwise default date.
@@ -114,11 +123,10 @@ autoboot|start)
     readclock -q || date 201301010000
 
     # We are not shutting down.
-    rm -f /etc/nologin
-
-    # Initialize files.
-    >/var/run/utmp				# /etc/utmp keeps track of logins
-    >/var/run/utmpx				# /etc/utmpx keeps track of logins
+    if [ -f /etc/nologin ]
+    then
+        rm -f /etc/nologin
+    fi
 
     # Use MFS binary only from kernel image?
     if [ "`sysenv bin_img`" = 1 ]
@@ -126,25 +134,18 @@ autoboot|start)
         bin_img="-i "
     fi
 
-    # Are we booting from CD?
-    bootcd="`/bin/sysenv bootcd`"
-
-    # If booting from CD, mounting is a special case.
-    # We know what to do - only /usr is mounted and it's readonly.
-    if [ "$bootcd" = 1 ]
-    then	usrdev="$cddev"p2
-    		echo "/usr on cd is $usrdev"
-		mount -r $usrdev /usr
-    else	
-    # If we're not booting from CD, fsck + mount using /etc/fstab.
-		fsck -x / $fflag $fsckopts
-		mount -a
-    fi
+    # fsck + mount using /etc/fstab.
+    fsck -x / $fflag $fsckopts
+    mount -a
 
     # Unmount and free now defunct ramdisk
     umount /dev/imgrd > /dev/null || echo "Failed to unmount boot ramdisk"
     ramdisk 0 /dev/imgrd || echo "Failed to free boot ramdisk"
 
+    # Initialize files.
+    >/var/run/utmp				# /etc/utmp keeps track of logins
+    >/var/run/utmpx				# /etc/utmpx keeps track of logins
+
     # Edit settings for boot system services
     if [ "`sysenv skip_boot_config`" != 1 ]
     then
@@ -197,18 +198,18 @@ down|stop)
     if [ -f /var/run/devmand.pid ]
     then
 	kill -INT `cat /var/run/devmand.pid`
-	# without this delay the following will 
+	# without this delay the following will
 	# be printed in the console
 	# RS: devman not running?
 	sleep 1
     fi
     #
-    # usbd needs to be stopped exactly 
+    # usbd needs to be stopped exactly
     # at this stage(before stopping devman
     # and after stopping the services
     # stated by devmand)
     if [ -x /usr/pkg/etc/rc.d/usbd ]
-    then 
+    then
 	/usr/pkg/etc/rc.d/usbd stop
     fi