electronjunkie

# Local filesystem mounting                     -*- shell-script -*-
#
################################################################
# File:
# /scripts/local
#
# Root, or / in these notes is the initrd's (busybox) root,
# not your system's root!
#
# You need the aufs module for this to work.  To do this install
# aufs on your base install, add aufs to: /etc/initramfs-tools/modules
# Now using your target kernel run:
# mkinitramfs -o initrd.img <kernel-name>
#
# make a directory, copy an initrd to it then cd to it and:
#
# mv initrd.img initrd.img.gz
# gunzip initrd.img.gz
#
# make sure aufs exists somewhere in /lib/modules/<uname -r>/
# After modifying local script, etc do the following in the initrd's
# root folder where /bin and /lib etc is to create a new initrd:
#
# find ./ -print | cpio -H newc -o > ../newinitrd.img
#
# Now tell grub to use this initrd for a RO root filesystem
################################################################
# Parameter: device node to check
# Echos fstype to stdout
# Return value: indicates if an fs could be recognized
get_fstype ()
{
        local FS FSTYPE FSSIZE RET
        FS="${1}"

        # vol_id has a more complete list of file systems,
        # but fstype is more robust
        eval $(fstype "${FS}" 2> /dev/null)
        if [ "$FSTYPE" = "unknown" ] && [ -x /lib/udev/vol_id ]; then
                FSTYPE=$(/lib/udev/vol_id -t "${FS}" 2> /dev/null)
        fi
        RET=$?

        if [ -z "${FSTYPE}" ]; then
                FSTYPE="unknown"
        fi

        echo "${FSTYPE}"
        return ${RET}
}

# Parameter: Where to mount the filesystem
mountroot ()
{
        [ "$quiet" != "y" ] && log_begin_msg "Running /scripts/local-top"
        run_scripts /scripts/local-top
        [ "$quiet" != "y" ] && log_end_msg

        wait_for_udev 10

        # If the root device hasn't shown up yet, give it a little while
        # to deal with removable devices
        if [ ! -e "${ROOT}" ] || ! $(get_fstype "${ROOT}" >/dev/null); then
                log_begin_msg "Waiting for root file system"

                # Default delay is 180s
                if [ -z "${ROOTDELAY}" ]; then
                        slumber=180
                else
                        slumber=${ROOTDELAY}
                fi
                if [ -x /sbin/usplash_write ]; then
                        /sbin/usplash_write "TIMEOUT ${slumber}" || true
                fi

                slumber=$(( ${slumber} * 10 ))
                while [ ! -e "${ROOT}" ] \
                || ! $(get_fstype "${ROOT}" >/dev/null); do
                        /bin/sleep 0.1
                        slumber=$(( ${slumber} - 1 ))
                        [ ${slumber} -gt 0 ] || break
                done

                if [ ${slumber} -gt 0 ]; then
                        log_end_msg 0
                else
                        log_end_msg 1 || true
                fi
                if [ -x /sbin/usplash_write ]; then
                        /sbin/usplash_write "TIMEOUT 15" || true
                fi
        fi

        # We've given up, but we'll let the user fix matters if they can
        while [ ! -e "${ROOT}" ]; do
                # give hint about renamed root
                case "${ROOT}" in
                /dev/hd*)
                        suffix="${ROOT#/dev/hd}"
                        major="${suffix%[[:digit:]]}"
                        major="${major%[[:digit:]]}"
                        if [ -d "/sys/block/sd${major}" ]; then
                                echo "WARNING bootdevice may be renamed. Try root=/dev/sd${suffix}"
                        fi
                        ;;
                /dev/sd*)
                        suffix="${ROOT#/dev/sd}"
                        major="${suffix%[[:digit:]]}"
                        major="${major%[[:digit:]]}"
                        if [ -d "/sys/block/hd${major}" ]; then
                                echo "WARNING bootdevice may be renamed. Try root=/dev/hd${suffix}"
                        fi
                        ;;
                esac
                echo "Gave up waiting for root device.  Common problems:"
                echo " - Boot args (cat /proc/cmdline)"
                echo "   - Check rootdelay= (did the system wait long enough?)"
                echo "   - Check root= (did the system wait for the right device?)"
                echo " - Missing modules (cat /proc/modules; ls /dev)"
                panic "ALERT!  ${ROOT} does not exist.  Dropping to a shell!"
        done

        # Get the root filesystem type if not set
        if [ -z "${ROOTFSTYPE}" ]; then
                FSTYPE=$(get_fstype "${ROOT}")
        else
                FSTYPE=${ROOTFSTYPE}
        fi

        [ "$quiet" != "y" ] && log_begin_msg "Running /scripts/local-premount"
        run_scripts /scripts/local-premount
        [ "$quiet" != "y" ] && log_end_msg

        if [ "${readonly}" = "y" ]; then
                roflag=-r
        else
                roflag=-w
        fi

        # FIXME This has no error checking

        modprobe ${FSTYPE}
##########################################################################
###### Mod'd by Brian Phelps aka Electronjunkie ##########################

         mkdir /root/.tmpfs
         mkdir /root/.rootfs

         mount -r -t ext2 /dev/sda1 /root/.rootfs

         modprobe aufs
         modprobe loop
         mount -t tmpfs -o size=20M tmpfs /root/.tmpfs

         mount -t aufs  -o br:/root/.tmpfs=rw:/root/.rootfs=ro none /root/
         mv /root/etc/fstab /root/etc/fstab.defunct

#########################################################################

        # FIXME This has no error checking
        # Mount root

        [ "$quiet" != "y" ] && log_begin_msg "Running /scripts/local-bottom"
        run_scripts /scripts/local-bottom
        [ "$quiet" != "y" ] && log_end_msg
}