#!/bin/sh

usage="Usage: $0 [-nopw] disk1|disk2"

nopw=0
if [ $# -gt 1 ] ; then
    if [ "$1" = "-nopw" ] ; then
	nopw=1
	shift
    fi
fi

# Set target disk

if [ $# -eq 1 ] ; then
    if [ "$1" = "disk1" ] ; then
	mtch="/dev/sdb1 /share/hdd/data ext3 rw 0 0"
	targ=/share/hdd/data
	targconf=/share/hdd/conf
	flag=.sdb1root
	htmlinfo="disk1, /dev/sdb1"
    elif [ "$1" = "disk2" ] ; then
	mtch="/dev/sda1 /share/flash/data ext3 rw 0 0"
	targ=/share/flash/data
	targconf=/share/flash/conf
	flag=.sda1root
	htmlinfo="disk2, /dev/sda1"
    else
	echo $usage
	exit 1
    fi
else
    echo $usage
    exit 1
fi

# Check that we can unsling at all!  An unsling operation creates a new
# rootfs, but it also marks the flash rootfs (with a flag file such as
# ".sda1root") so that subsequent boots do not create the "var.state"
# and "dev.state" mounts.  Without those mounts, though, an attempt to
# unsling will write a new rootfs on the target with an empty /dev
# directory, which doesnt' work really well.  So this check is all about
# making sure that we are in a state in which we are capable of
# performing the unsling operation.

echo "Checking if able to unsling..."
echo
m1="/dev/root /dev.state jffs2 rw 0 0"
m2="/dev/root /var.state jffs2 rw 0 0"
if ! grep "$m1" /proc/mounts >/dev/null 2>&1 || ! grep "$m2" /proc/mounts >/dev/null 2>&1 ; then
    echo "Error: This system is unable to properly unsling because certain"
    echo "required mounts (dev.state and/or var.state) are not available."
    echo "This is most probably because you have already unslung this system."
    echo

    if   [ -f /.sda1root ] ; then
	rm -f /.sda1root
    elif [ -f /.sdb1root ] ; then
	rm -f /.sdb1root
    elif [ -f /.sda2root ] ; then
	rm -f /.sda2root
    elif [ -f /.sdb2root ] ; then
	rm -f /.sdb2root
    else
	echo "However, in this case, the flags that indicate an already-unslung"
	echo "system seem to be missing.  Try restarting your NSLU2 to correct,"
	echo "but if the problem persists, try re-flashing your NSLU2."
	exit 1
    fi
    echo "The flags that indicate an already-unslung system have now been"
    echo "removed and the required mounts should now become present after"
    echo "reboot of the NSLU2."
    echo
    echo "1) Please unplug all drives from the NSLU2,"
    echo "2) reboot,"
    echo "3) and retry the unslinging process."
    exit 1
fi

# Check it's a real mount point

echo "Waiting for $targ ..."
CNT=120
while [ $CNT -gt 0 ]
do
   if grep "$mtch" /proc/mounts >/dev/null 2>&1 ; then
       echo
       echo "Target disk is $targ"
       CNT=-1
   else
       echo -ne "\r$CNT   "
       sleep 1
       CNT=`expr $CNT - 1`
   fi
done
if [ $CNT -eq 0 ] ; then
   echo
   echo "Error: $targ ($htmlinfo) is not a mounted disk"
   exit 1
fi

# Do a quick sanity check to make sure we're unslinging to a disk that's been
# formatted by the Linksys code.

echo "Checking that $targ has been properly formatted..."
if ! [ -d $targ/public ] || ! [ -f $targconf/.dongle ] || ! [ -f $targconf/passwd ] ; then
    echo
    echo "Error: $targ does not appear to have been formatted by the"
    echo "Linksys formatting utility.  Please go to the web interface,"
    echo "and format the drive before unslinging."
    exit 1
fi

echo "Checking that $targ is clean..."
if [ -f $targ/.unslung ] ; then
    echo
    echo "Error: $targ appears to have already been unslung to:"
    cat $targ/.unslung
    echo "Please go to the web interface, and format the drive before"
    echo "unslinging."
    echo
    echo "(Or, if you wish to unsling without removing the current root"
    echo "filesystem, simply remove the file $targ/.unslung and retry"
    echo "the unsling -- but beware, you enter uncharted territory!)"
    exit 1
fi

# Change the root password
if [ "$nopw" = 0 ] ; then
   echo
   echo "Please enter the new root password.  This will be the new root"
   echo "password used when the NSLU2 boots up with or without disks"
   echo
   passwd
   if [ $? != 0 ] ; then
       echo "Error setting password."
       exit 1
   fi
   cp /etc/passwd /usr/local/passwd
   cp /etc/passwd $targconf/passwd
fi

# Start at the root directory

cd /

# Save the existing ipkg database.

rm -rf $targ/usr/lib/ipkg.old
if [ -f $targ/usr/lib/ipkg/status ] ; then
	mv $targ/usr/lib/ipkg $targ/usr/lib/ipkg.old
fi

# Copy the complete rootfs to the target.

echo
echo "Copying the complete rootfs from / to $targ ..."
/usr/bin/find / -print0 -mount | /usr/bin/cpio -p -0 -d -m -u $targ
rm -rf $targ/dev ; mv $targ/dev.state $targ/dev
rm -rf $targ/var ; mv $targ/var.state $targ/var

# Copy over the existing ipkg database.

if [ -f $targ/usr/lib/ipkg.old/status ] ; then
	echo "Preserving existing ipkg database on target disk."
	( cd $targ/usr/lib/ipkg.old ; tar cf - . ) | ( cd $targ/usr/lib/ipkg ; tar xf - )
fi

echo "Linking /usr/bin/ipkg executable on target disk."
rm -f $targ/usr/bin/ipkg ; ln -s /usr/bin/ipkg-cl $targ/usr/bin/ipkg

echo "Linking /etc/motd to the unslung motd on target disk."
rm -f $targ/etc/motd ; ln -s /etc/motd-un $targ/etc/motd

echo "Updating /home/httpd/html/home.htm with target disk info."
sedcommand="s#Running.from.Internal.Flash#Unslung to $htmlinfo#"
rm -f $targ/home/httpd/html/home.htm_bak
cp $targ/home/httpd/html/home.htm $targ/home/httpd/html/home.htm_bak
sed "$sedcommand" $targ/home/httpd/html/home.htm_bak > $targ/home/httpd/html/home.htm
chmod 644 $targ/home/httpd/html/home.htm

# Create the boot flag file.

rm -f /.sd??root $targ/.sd??root

echo "Creating /$flag to direct switchbox to boot from $targ."
echo > /$flag
echo > $targ/$flag

# Done

echo
echo "Unsling complete."
echo
echo "Leave the device $htmlinfo plugged in, and reboot"
echo "in order to boot this system up into unslung mode."

exit 0