#!/bin/sh
# Install an image from a USB stick if there's one plugged in and a file
# named <platformprefix>-*.gi exists in its root directory.
#
. /etc/utils.sh

log()
{
  echo "$(basename $0):" "$@" >&2
}


SERIAL_PORT=/dev/ttyS0

log2serial()
{
  if [ "$(stty -F ${SERIAL_PORT} speed)" != "115200" ] ; then
    stty -F ${SERIAL_PORT} sane
    stty -F ${SERIAL_PORT} 115200
  fi

  echo "$@" > ${SERIAL_PORT}
}


findall()
{
  local path=
  for path in "$@"; do
    [ -e "$path" ] && echo "$path"
  done
}


try_install()
{
  if ! grep -q root= /proc/cmdline; then
    # Only wait for USB when not booting from the hard drive,
    # otherwise a mass-storage device should be enumerated at
    # this point
    wait-scsi usb
  fi
  any=
  current_ver=$(cat /etc/version)
  platform_prefix=${current_ver%%-*}
  for path in $(findall /sys/block/sd*/device); do
    if realpath $path | grep -q -e "/usb[0-9]*/"; then
      any=1
      dev=$(basename $(dirname $path))
      log "Checking $dev for installable images."
      for partpath in $(findall /sys/block/$dev/*/partition); do
        part=$(basename $(dirname $partpath))
        log "Trying $part:"
        mkdir -p /tmp/installsrc
        if mount -t vfat /dev/$part /tmp/installsrc; then
          log "  mounted."

          if [ -e /tmp/installsrc/factory_status ]; then
            # Note for the future: never execute files from USB.
            # Anybody can put anything they want on a USB stick.
            #
            # In this case they could make the factory_status server
            # start, which wouldn't actually hurt anything.
            echo :>/tmp/factory_status
          fi

          # we deliberately use the last *.gi file alphabetically.  That
          # one has the highest version number so it's the best choice.
          lastimg=
          for img in $(findall /tmp/installsrc/*.gi); do
            imgbase=$(basename "$img")
            if startswith "$imgbase" "$platform_prefix-"; then
              log "  considering $imgbase"
              lastimg=$img
            else
              log "  skipping $imgbase (wrong platform)"
            fi
          done
          if [ "$(basename $lastimg)" = "$current_ver.gi" ]; then
            log "  already installed; skipping."
          elif [ -n "$lastimg" ]; then
            log2serial "USB upgrade from $current_ver to $(basename $lastimg)"
            log "  installing $(basename $lastimg)"
            leds 15 0 15 0 15 0  # super noisy leds while doing update
            if ginstall -t "$lastimg" -p other; then
              log "  installed successfully."
              leds 0  # turn off leds, indicating finished + halted
            else
              log "  ...install failed!"
              leds 1 0  # blinking red means install tried and failed
            fi
            umount /tmp/installsrc
            log "Please remove USB and reboot."
            log2serial "Please remove USB and reboot."
            while sleep 10; do
              echo -n '.'
            done
          else
            log "  no files matching *.gi"
          fi
          umount /tmp/installsrc
        fi
      done  # partition loop
    fi
  done  # disk loop
  [ -z "$any" ] && log "no removable media found."
}


case "$1" in
  start)
    try_install
    ;;
  stop)
    ;;
  restart|reload)
    ;;
  *)
    echo "Usage: $0 {start|stop|restart}" >&2
    exit 1
esac