#!/bin/bash
set -e

# Updater for the Shadow.
#
# Will flash the mmc partition not in use.  Makes some effort not to
# overwrite your data by mistake:
#
# * filesystem must have /etc/build and we must parse it
# * dmidecode must identify board as one with a downloadable update
# * /proc/cmdline must have "root=/dev/mmcblk0p[23]"
# * alternate /dev/mmcblk0p[32] must exist and be a block device
# * rootfs is squashfs

# Known problems:
#
# * when manually interrupted by ctrl-c or ctrl-\, dd finishes before
#   stopping, and grub config is not updated, and the system won't
#   boot on updated partition [low risk of occurence in the wild, and
#   auto-fixing on next attempt]


# params

TIMEOUT=5

# identify platform

case $(dmidecode -s baseboard-product-name) in
    UP-CHT01) PLATFORM=up-board ;;
    BP-FP4-LC) PLATFORM=amdfalconx86 ;;
    *) PLATFORM=unknown ;;
esac

SERVER=http://update.blade-group.fr/updates
KEYRING=/usr/share/updater.keyring

DEFAULTBRANCH="prod"
if [ -r /etc/blade/branch ]; then
    DEFAULTBRANCH=$(cat /etc/blade/branch)
fi


die() {
    echo >&2 "ERROR: $*"
    exit 1
}

usage()
{
    cat <<EOF
Usage:
    $(basename $0) [options] [branch|version]

Options:
    --help, -h:    This help
    --force, -f:   Apply update even if already running same version.
    --fast:        Don't rate-limit the download
    --reboot:      Reboot if an update was applied
    --graphic      Show graphical notification screens
    --imgdir <dir> Show graphical notification screens from <dir>

Example branches:
    prod           Production image for real customers (default)
    preprod        prod-candidate, for beta testers
    testing        preprod-candidate, for internal testing
    <branch>-test  <branch>-candidate for last checks before publication

EOF
}

wrongusage()
{
    echo >&2 "ERROR: $*"
    usage
    exit 1
}

notify()
{
    [ $GRAPHIC = 1 ] || return 0
    killall -9 feh || true
    feh --fullscreen "$IMGDIR"/"$1".png &
}

check_squashfs()
{
    if command -v unsquashfs >/dev/null; then
        unsquashfs -l "$1" >/dev/null
    else
        echo "WARNING: unsquashfs not found, NOT checking filesystem integrity"
    fi
}

FORCE=0
FEED="$DEFAULTBRANCH"
REBOOT=0
GRAPHIC=0
IMGDIR=/usr/share/shadow/images
# 100KB/s is below 1Mb/s
MAYBELIMIT="--limit-rate 100k"
while [ $# -gt 0 ]; do
    case "$1" in
        -h|--help) usage; exit 0 ;;
        -f|--force) FORCE=$((FORCE+1)) ;;
        --fast) MAYBELIMIT="" ;;
        --reboot) REBOOT=1 ;;
        --graphic) GRAPHIC=1 ;;
        --imgdir) GRAPHIC=1; IMGDIR="$2"; shift ;;
        -*) wrongusage "Unknown option '$1'" ;;
        *) break ;;
    esac
    shift
done
if [ $# -gt 0 ]; then
    FEED="$1"
    shift
fi
[ $# = 0 ] || wrongusage "Too many non-option arguments"

# locate this version's root partition
for opt in $(cat /proc/cmdline); do
    case "$opt" in
        root=*) MYPART=${opt#*=}; break ;;
    esac
done

if ! mount | grep -q ' / .* squashfs '; then
    echo "rootfs is not a squashfs, not updating"
    exit 0
fi

if [[ "$FEED" =~ ^[0-9]+$ ]]; then
    FEEDVERSION="$FEED"
else
    FEED="$PLATFORM/$FEED"

    if [ $GRAPHIC = 1 ]; then
        trap "killall -9 feh || true" EXIT
    fi

    notify checking-updates

    FEEDFILE=$(mktemp -t "updater.XXXXXX")
    curl --silent --fail $MAYBELIMIT "$SERVER/$FEED" -o "$FEEDFILE" || die "failed to check for '$FEED' update"

    FEEDVERSION=$(cat $FEEDFILE)
    rm $FEEDFILE
    [ -n "$FEEDVERSION" ] || die "no $FEED version!"
    echo "$FEED version is $FEEDVERSION"
fi

# this partition's version
[ -f /etc/build ] || die "Cannot find /etc/build for Shadow image version"
CURRENT=$(grep "^DATETIME =" /etc/build | cut -d= -f2 | tr -d ' ')
expr "$CURRENT" : "[0-9]*$" >/dev/null || die "Cannot understand rev '$CURRENT'"
[ 14 -eq $(expr "$CURRENT" : "[0-9]*$") ] || die "Revision should have 14 digits: '$CURRENT'"
echo "Current version is $CURRENT"

if [ "$FEEDVERSION" -eq "$CURRENT" ]; then
    echo "Shadow is uptodate"
    if [ $FORCE -ge 1 ]; then
        echo " --force given, proceeding anyway"
    else
        exit 0
    fi
elif [ ! "$FEEDVERSION" -gt "$CURRENT" ]; then
    echo "Version inconsistency: $FEED '$FEEDVERSION' is older than '$CURRENT'"
    if [ $FORCE -ge 1 ]; then
        echo " --force given, proceeding anyway"
    else
        exit 3
    fi
fi

# deduce other partition
case "$MYPART" in
    /dev/mmcblk0p2) MYPARTNUM=2; NEWPARTNUM=3 ;;
    /dev/mmcblk0p3) MYPARTNUM=3; NEWPARTNUM=2 ;;
    *) die "unknown root partition '$MYPART'" ;;
esac
NEWPART=/dev/mmcblk0p$NEWPARTNUM

[ -b $NEWPART ] || die "partition $NEWPART does not exist"

# other partition's version
while true; do                  # this is poor-man's do-while(0)
    # check the filesystem can be completely read
    if ! check_squashfs $NEWPART; then
        echo "Other partition's filesystem is bad, will reflash"
        break;
    fi

    if ! mount -oro $NEWPART /mnt; then
        # this should never happen since we checked it, but old images
        # don't have unsquashfs
        echo "Could not mount other partition, will flash"
        break
    fi

    OTHERVERS=$(grep "^DATETIME =" /mnt/etc/build | cut -d= -f2 | tr -d ' ')
    umount $NEWPART
    if ! [ "$OTHERVERS" -gt 0 ] 2>/dev/null; then
        echo "Cannot understand '$OTHERVERS' as numeric version, will reflash"
        break
    fi

    echo "Other partition had $OTHERVERS"

    break
done

IMG=shadow-image-x11-${PLATFORM}-${FEEDVERSION}.rootfs.squashfs

notify "downloading-update"

echo "dowloading update..."
wget -q $SERVER/$PLATFORM/$IMG.sig -O /tmp/$IMG.sig || die "failed to fetch update signature"
wget $SERVER/$PLATFORM/$IMG -O /tmp/$IMG || die "failed to fetch update"

notify "applying-update"

echo "verifying update data..."
gpgv --keyring $KEYRING /tmp/$IMG.sig /tmp/$IMG ||
    die "failed to verify update"

echo "flashing update..."
dd if=/tmp/$IMG of=$NEWPART bs=4M || die "failed to flash update"
sync

echo "verifying update..."
check_squashfs $NEWPART

echo "updating bootentries..."
mount /dev/mmcblk0p1 /mnt
EFIDIR=/mnt/EFI/BOOT
if [ "$FEED" = "master" ]; then
    QUIET=''
else
    QUIET='quiet'
fi
cat > $EFIDIR/rootpart.cfg <<EOF
timeout=$TIMEOUT
timeout_style=countdown

#set prefix=(\${rootdsk},gpt$NEWPARTNUM)/usr/lib64/grub

if loadfont (\${rootdsk},gpt$NEWPARTNUM)/usr/share/grub/unicode.pf2
then
    set gfxmode=1920x1080,2560x1440,1290x1200,1920x1080,1280x1024,1024x768,auto
    set gfxpayload=keep
    terminal_output gfxterm
fi

menuentry 'Shadow (image $FEEDVERSION)' {
linux (\${rootdsk},gpt$NEWPARTNUM)/boot/bzImage root=$NEWPART \${opts}
}
menuentry 'Shadow previous (image $CURRENT)' {
linux (\${rootdsk},gpt$MYPARTNUM)/boot/bzImage root=$MYPART $QUIET \${opts}
}
EOF
sync
cat > $EFIDIR/oldrootpart.cfg <<EOF
timeout=$TIMEOUT
timeout_style=countdown

#set prefix=(\${rootdsk},gpt$NEWPARTNUM)/usr/lib64/grub

if loadfont (\${rootdsk},gpt$NEWPARTNUM)/usr/share/grub/unicode.pf2
then
    set gfxmode=1920x1080,2560x1440,1290x1200,1920x1080,1280x1024,1024x768,auto
    set gfxpayload=keep
    terminal_output gfxterm
fi

menuentry 'Shadow recovery (image $CURRENT)' {
linux (\${rootdsk},gpt$MYPARTNUM)/boot/bzImage root=$MYPART $QUIET \${opts}
}
EOF
umount /dev/mmcblk0p1
sync

if [ $REBOOT = 1 ]; then
    notify "reboting"
    echo "Update finished, rebooting..."
    reboot
else
    echo "Update finished."
fi

# signal update to caller
exit 2