zboot

#!/bin/sh
ZX="EVE"

set -e

#
# How do you get the root dev from a container? With the next two
# functions.
#

makewords() {
    awk '{print $0}' RS=' ' < $1
}

rdev () {
    uuid=$(makewords /proc/cmdline | grep PARTUUID | awk -F = '{print $3}')
    dev=$(lsblk -l -o name,PARTUUID | awk -v uuid="$uuid" '$2==uuid {print $1}')
    echo $dev
}

rootdev=$(echo "/dev/"$(rdev))
rootdsk=$(echo "/dev/"$(lsblk -no pkname ${rootdev}))

usage() {
    echo "${ZX} Boot Control and Administration API tool."
    echo
    echo "Usage:"
    echo "       $(basename "$0") {partdev|partdevsize} <LABEL>"
    echo "       $(basename "$0") partstate <LABEL> [-d]"
    echo "       $(basename "$0") set_partstate <LABEL> <STATE>"
    echo "       $(basename "$0") {curpart|reset}"
    echo
    echo "Commands:"
    echo "    partdev: return device of partition LABEL."
    echo "    partstate: return state of partition LABEL. Add -d flag for detailed decode."
    echo "    partdevsize: return device size of partition LABEL."
    echo "    set_partstate: Set state of partition LABEL to STATE."
    echo "    curpart: return label of current root partition."
    echo "    reset: reboot the machine with a certain hurry."
    echo "    poweroff: power off the machine."
    echo
    echo "<IMAGE> can be IMGA, IMG, or any other GPT partition label."
    echo "<STATE> can be either 'active', or 'unused', or 'updating'."
    echo "A partition can be in 'inprogress' state -- indicating either"
    echo "a current attempt at updating into it or a failure to do so"
    echo "in the past -- but such state cannot be set by this tool"
    echo

    exit 1
}

partno() {
    cgpt find -l $1 -n ${rootdsk}
}

#
# CURPART: get partition label of current root
#
curpart() {
    if [ ! $# -eq 0 ]; then
        usage
    fi
    lsblk -o PARTLABEL -n ${rootdev}
}

#
# PARTDEV: get device from partition label
#
partdev() {
    if [ ! $# -eq 1 ]; then
        usage
    fi
    cgpt find -l $1 ${rootdsk}
}

#
# PARTDEVSIZE: get device size from partition label
#
partdevsize() {
    if [ ! $# -eq 1 ]; then
        usage
    fi
    dev="$(partdev "$@")"
    lsblk -b -n -o SIZE "$dev"
}

#
# PARTDEVALL: get device from partition label, search all drives
#
partdevall() {
    if [ ! $# -eq 1 ]; then
        usage
    fi
    cgpt find -l "$1"
}

#
# DECODE_ATTR <attr>: decode and explain an unknown attribute value
#
decode_attr() {
    attr=$1
    # Extract bit fields using the formulas
    priority=$((attr & 0x0F))
    tries=$(((attr >> 4) & 0x0F))
    successful=$(((attr >> 8) & 0x01))

    # Check for unexpected bits (bits 9 and above)
    high_bits=$((attr >> 9))

    echo "UNKNOWN 0x$(printf %x "$attr") decoded:"
    echo "  Priority: $priority"
    echo "  Tries left: $tries"
    echo "  Successful: $successful"
    if [ $high_bits -ne 0 ]; then
        echo "  Reserved bits set: 0x$(printf %x "$high_bits")"
    fi
}

#
# PARTSTATE <LABEL> [-d]: get state from partition label
#
partstate() {
    decode_flag=0

    if [ $# -lt 1 ] || [ $# -gt 2 ]; then
        usage
    fi

    # Parse optional -d flag (after label for backward compatibility)
    if [ $# -eq 2 ] && [ "$2" = "-d" ]; then
        decode_flag=1
    fi

    pn=$(partno "$1")
    attr=$(cgpt show -i "${pn}" -A "${rootdsk}")

    if [ "$decode_flag" -eq 1 ]; then
        decode_attr "${attr}"
    fi

    case "${attr}" in
        0x102) state="active" ;;
        0x13) state="updating" ;;
        0x3) state="inprogress" ;;
        0) state="unused" ;;
        *) state="UNKNOWN ${attr}" ;;
    esac
    echo "${state}"
}

#
# SETPARTSTATE <LABEL> <STATE>: set partition state
#
set_partstate() {
    if [ ! $# -eq 2 ]; then
        usage
    fi

    pn=$(partno "$1")
    case $2 in
        "active") attr=0x102 ;;
        "updating") attr=0x13 ;;
        "unused") attr=0 ;;
        *)
            echo "Unknown state '$2'";
            exit 2;
            ;;
    esac

    cgpt add -i "${pn}" -A "${attr}" "${rootdsk}"
}

#
# RESET: shutdown and restart
#
reset() {
    if [ ! $# -eq 0 ]; then
        usage
    fi

    # Warning, this does not really play nice with init
    # do not sync, don't go through init
    /sbin/reboot -n -f
}

#
# POWEROFF
#
poweroff() {
    # Warning, this does not really play nice with init
    # do not sync, don't go through init
    /sbin/poweroff -f
}

if [ $# -eq 0 ]; then
    usage
fi

cmd=$1
shift 1

case $cmd in
    curpart) curpart ;;
    partdev) partdev "$@" ;;
    partdevsize) partdevsize "$@" ;;
    partdevall) partdevall "$@" ;;
    partstate) partstate "$@" ;;
    set_partstate) set_partstate "$@" ;;
    reset) reset ;;
    poweroff) poweroff ;;
    *) usage ;;
esac