#!/bin/bash

#
# Copyright (c) 2012, AVG Technologies CZ, s.r.o., www.avg.com
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.


DIALOG=dialog
DIALOG_OK=0
DIALOG_CANCEL=1
DIALOG_HELP=2
DIALOG_EXTRA=3
DIALOG_PSCR=131
DIALOG_ESC=255
ARL_ERROR_LOG_FILE="/tmp/arl_error.log"
VALUE=""
ARL_USBDIR="${0%/*}"
USB_DEVICES_FILE="$ARL_USBDIR/usb_devs_file"

error()
{
    # $1 - error message

    $DIALOG --colors --backtitle "AVG Rescue CD" --msgbox "Error:\n\n\Z1${1}\Zn" 10 70
}

success()
{
    # $1 - success message

    $DIALOG --colors --backtitle "AVG Rescue CD" --msgbox "\Z2$1\Zn" 8 70
}

infobox()
{
    # $1 - title
    # $2 - message

    $DIALOG --backtitle "AVG Rescue CD" --title "$1" --infobox "\n$2" 5 70
}

cmd()
{
    # 1 - command
    # 2 - infobox message (optional)
    #   - cmd_INFOBOX_TITLE (optional)

    local cmd="$1"
    local info_msg="$2"
    local rv

    [ -n "$info_msg" ] && infobox "$cmd_INFOBOX_TITLE" "$info_msg"

    VALUE="`eval $cmd 2>&1`"
    rv=$?
    if [ $rv -ne 0 ]
    then
        echo -e "$cmd  returned $rv:\n\t$VALUE" >> $ARL_ERROR_LOG_FILE
        error "$cmd:\n$VALUE"
    fi

    return $rv
}

yesno()
{
    # $1 - question
    # $2 - height
    # $3 - width

    $DIALOG --backtitle "AVG Rescue CD" --colors --yesno "$1" $2 $3
}

usb_devices_radiolist()
{
    local path
    local dev
    local model
    local vendor
    local removable
    local devices
    local size
    local enable="on"

    for path in `find /sys/block/ -maxdepth 1 -iname sd* 2>/dev/null`
    do
        removable=`cat $path/removable`
        [ $removable -eq 0 ] && continue

        devices=`find $path/sd* -maxdepth 1 -iname sd* 2>/dev/null`

        # no partition
        [ -z "$devices" ] && devices=$path

        for device in $devices
        do
            dev=`basename $device`

            VALUE="`awk '/^.* '$dev'$/{print $3}' /proc/partitions`"
            size="$(($VALUE/1024))"

            if [ $size -lt 510 ]
            then
                continue
            elif [ $size -lt 1024 ]
            then
                size="${size}MB"
            else
                size="$(($size/1024))GB"
            fi

            model=`cat $path/device/model`
            vendor=`cat $path/device/vendor`

            echo "$dev \"$vendor $model $size\" $enable" >> $USB_DEVICES_FILE

            enable="off"
        done
    done
}

usb_show_devices()
{
    VALUE=`$DIALOG --backtitle "AVG Rescue CD" \
        --title "USB Flash Drive" \
        --cancel-label "Return" \
        --radiolist "Please select drive" 15 70 10 \
        --file $USB_DEVICES_FILE \
        2>&1 1>&3`

    return $?
}

usb_conf_devices()
{
    local rv

    rm -f $USB_DEVICES_FILE
    usb_devices_radiolist
    if [ ! -f "$USB_DEVICES_FILE" ]
    then
        error "No USB Flash Drive found!"
        return 1
    fi

    usb_show_devices
    rv=$?
    rm -f $USB_DEVICES_FILE

    if [ $rv -eq $DIALOG_CANCEL -o $rv -eq $DIALOG_ESC -o $rv -eq $DIALOG_PSCR ]
    then
        return 1
    fi

    if [ $rv -ne $DIALOG_OK ]
    then

        echo "error: usb devices dialog: $rv"
        exit
    fi

    return 0
}

usb_umount()
{
    # $1 - dev name, e.g. sdb

    local mntpoints
    local mntpoint
    local dev="$1"

    mntpoints=`cat /proc/mounts | grep $dev | cut -d' ' -f2`
    for mntpoint in $mntpoints
    do
        cmd "umount $mntpoint" "unmounting $dev" || return 1
    done
}

usb_copy()
{
    # $1 - arl pck files path e.g. /mnt/usb, /mnt/sr0, ...
    # $2 - usb mountpoint

    local arl_files="f1.msg syslinux.cfg memtest menu.c32 libutil.c32 vmlinuz CHANGELOG arl-version initrd.lzm arl.conf"
    local f

    for f in $arl_files
    do
        cmd "cp $1/$f $2" "Copying file: $f" || return 1
    done

    return 0
}

usb_ext2_show_size()
{
    # $1 - available free space

    VALUE=`$DIALOG --backtitle "AVG Rescue CD" \
        --title "Select" \
        --cancel-label "Return" \
        --inputbox \
        "Please enter ext2 file system size. Minimum size is 500MB.
Maximum free space size available on USB drive is $1MB" \
        10 65 \
        "500" \
        2>&1 1>&3`

    return $?
}

usb_ext2_size()
{
    # $1 - dev full path

    local dev_escp="`echo $1 | sed 's%\/%\\\/%g'`"
    local avail=`df $1 | grep -v Filesystem |  awk '/'$dev_escp'/{print $4}'`

    usb_ext2_show_size $avail
    if [ $? -eq $DIALOG_CANCEL -o $? -eq $DIALOG_ESC -o $? -eq $DIALOG_PSCR ]
    then
        return 1
    fi

    if [ $? -ne $DIALOG_OK ]
    then
        quit "error: ext2 file system size dialog: $?"
    fi

    if [ $VALUE -gt $(($avail/1024)) ]
    then
        error "There is not enough free space on the USB drive"
        return 1
    fi

    if [ 500 -gt $VALUE ]
    then
        error "The minimum ext2 file system size is 500MB"
        return 1
    fi

    return 0
}

usb_ext2()
{
    # $1 - dst. usb size
    # $2 - dst. usb mount point
    # $3 - src. arl_rootfs.ext2 mount point

    local rv=0
    local loopdev="`losetup -f`"

    cmd "dd if=/dev/zero of=$2/arl_rootfs.ext2 bs=1M count=$1" "Creating arl_rootfs.ext2 loopback device" &&
    cmd "losetup $loopdev $2/arl_rootfs.ext2" "Setting up loopback device" &&
    cmd "mkfs.ext2 $loopdev" "Creating ext2 file system" &&
    cmd "mkdir -p /mnt/ext2" "Creating /mnt/ext2 directory" &&
    cmd "mount $loopdev /mnt/ext2" "Mounting ext2 file system" || return 1

    cmd "cp -a $3/* /mnt/ext2" "Creating root file system in ext2 fs" || rv=$?

    cmd "umount /mnt/ext2" "Umounting ext2 file system" &&
    cmd "rmdir /mnt/ext2" &&
    cmd "losetup -d $loopdev" "Removing loopback device" || rv=$?

    return $rv
}

usb_create()
{
    # $1 - dev name, e.g. sdb or sdb1,...
    # $2 - arl src files path e.g. /mnt/usb, /mnt/sr0, ...

    local rv=0
    local partition=${1:3:1}
    [ -z "$partition" ] && partition="1"
    local device=${1:0:3}

    cmd "mkdir -p /mnt/usb_origfs" &&
    cmd "mount $ARL_USBDIR/arl_rootfs.ext2 /mnt/usb_origfs" || rv=$?

    if [ $rv -eq 0 ]
    then
        cmd "mkdir -p /mnt/usb_new" "Mounting USB..." &&
        mount -t vfat /dev/$1 /mnt/usb_new 2>/dev/null ||
        mount -t ntfs /dev/$1 /mnt/usb_new 2>/dev/null || rv=$?

        if [ $rv -ne 0 ]
        then
            error "Different file system, FAT16/FAT32/NTFS, required!"
        else
            usb_ext2_size "/dev/$1" &&
            usb_ext2 "$VALUE" "/mnt/usb_new" "/mnt/usb_origfs" &&
            usb_copy "$2" "/mnt/usb_new" || rv=$?

            cmd "umount /mnt/usb_new" "Unmounting USB..." &&
            cmd "rmdir /mnt/usb_new"

            cmd "/mnt/usb_origfs/opt/bin/syslinux -i /dev/$1" "Installing syslinux..." &&

            # create mbr if partition specified
            if [ ${#1} -gt 3 ]
            then
                cmd "dd if=/dev/zero of=/dev/$device bs=446 count=1" "Creating MBR..." &&
                cmd "cat /mnt/usb_origfs/usr/lib/syslinux/mbr.bin > /dev/$device" || rv=$?
            fi &&

            sleep 1
        fi

        cmd "umount /mnt/usb_origfs" &&
        cmd "rmdir /mnt/usb_origfs"
    fi

    return $rv
}

usb()
{
    cmd_INFOBOX_TITLE="USB Flash Drive"

    if [ -z "`which $DIALOG`" ]
    then
        echo "Please install the dialog utility at first."
        echo "For example: \$ sudo apt-get install dialog"
        return
    fi

    if [ ! -f "$ARL_USBDIR/arl-version" ]
    then
        error "arl-version file was not found!"
        return
    fi

    usb_conf_devices
    if [ $? -eq 1 ]
    then
        return
    fi
    dev=$VALUE

    yesno "All the AVG Rescue CD data on the USB Flash Drive will be rewritten?\n\n\
Do you really want to continue?" 8 70
    if [ $? -eq $DIALOG_CANCEL -o $? -eq $DIALOG_ESC -o $? -eq $DIALOG_PSCR ]
    then
        return
    fi

    usb_umount $dev
    usb_create $dev "$ARL_USBDIR"
    if [ $? -ne 0 ]
    then
        error "Bootable USB Flash Drive was NOT created!"
        return
    fi

    success "Bootable USB Flash Drive successfully created."
}

exec 3>&1

if [ $(id -u) -ne 0 ]
then
    echo "ERROR: Try to run this as root."
    # LSB specification errorcode
    exit 4
fi

usb