init

#!/bin/busybox sh

rescue_shell() {
    echo "$@"
    echo "Something went wrong. Dropping you to a shell."
    busybox --install -s
    exec /bin/sh
}

activate_vgs() {
    /sbin/pvscan --uuid --verbose || rescue_shell "Error while scanning physical volumes"
    /sbin/vgscan --mknodes --verbose || rescue_shell "Error while scanning volume groups"

    for vg in $(/sbin/vgscan | grep "Found volume group" | cut -d\" -f2) ; do
        echo "Activating volume group: $vg"
        /sbin/vgchange -ay $vg --sysinit || rescue_shell "Error while activating $vg"
        /sbin/vgmknodes --ignorelockingfailure $vg || rescue_shell "Error while making nodes for $vg"
    done
}

find_rootfs() {
    for cmd in $(cat /proc/cmdline) ; do
        case $cmd in
            root=*)
                type=$(echo $cmd | cut -d= -f2)
                echo "Mounting rootfs"
                if [ $type == "LABEL" ] || [ $type == "UUID" ] ; then
                    uuid=$(echo $cmd | cut -d= -f3)
                    mount -o ro $(findfs "$type"="$uuid") /mnt/root
                    return
                else
                    mount -o ro $(echo $cmd | cut -d= -f2) /mnt/root
                    return
                fi
            ;;
        esac
    done

    rescue_shell "No root partition found"
}

check_filesystem() {
    # most of code coming from /etc/init.d/fsck

    local fsck_opts= check_extra= RC_UNAME=$(uname -s)

    # FIXME : get_bootparam forcefsck
    if [ -e /forcefsck ]; then
        fsck_opts="$fsck_opts -f"
        check_extra="(check forced)"
    fi

    echo "Checking local filesystem $check_extra : $1"

    if [ "$RC_UNAME" = Linux ]; then
        fsck_opts="$fsck_opts -C0 -T"
    fi

    trap : INT QUIT

    # using our own fsck, not the builtin one from busybox
    /sbin/fsck -p $fsck_opts $1

    case $? in
        0)      return 0;;
        1)      echo "Filesystem repaired"; return 0;;
        2|3)    if [ "$RC_UNAME" = Linux ]; then
                        echo "Filesystem repaired, but reboot needed"
                        reboot -f
                else
                        rescue_shell "Filesystem still have errors; manual fsck required"
                fi;;
        4)      if [ "$RC_UNAME" = Linux ]; then
                        rescue_shell "Fileystem errors left uncorrected, aborting"
                else
                        echo "Filesystem repaired, but reboot needed"
                        reboot
                fi;;
        8)      echo "Operational error"; return 0;;
        12)     echo "fsck interrupted";;
        *)      echo "Filesystem couldn't be fixed";;
    esac
    rescue_shell
}

# temporarily mount proc and sys
mount -t proc none /proc
mount -t sysfs none /sys
mount -t devtmpfs none /dev

# disable kernel messages from popping onto the screen
echo 0 > /proc/sys/kernel/printk

# clear the screen
clear

# scan for vgs and activate each and every one of them
activate_vgs || rescue_shell "Error while activating volume groups"

# mounting rootfs on /mnt/root
find_rootfs || rescue_shell "Error while finding root filesystem"

# space separated list of mountpoints that ...
mountpoints=""

# ... we want to find in /etc/fstab ...
ln -s /mnt/root/etc/fstab /etc/fstab

# ... to check filesystems and mount our devices.
for m in $mountpoints ; do
    check_filesystem $m

    echo "Mounting $m"
    # mount the device and ...
    mount $m || rescue_shell "Error while mounting $m"

    # ... move the tree to its final location
    mount --move $m "/mnt/root"$m || rescue_shell "Error while moving $m"
done

echo "All done. Switching to real root."

# clean up. The init process will remount proc sys and dev later
umount /proc
umount /sys
umount /dev

# switch to the real root and execute init
exec switch_root /mnt/root /sbin/init