#!/bin/sh
#
# Load SSH host key from SD card.
#

start() {

    # If host key exists, do nothing.
    [ -f /etc/dropbear/dropbear_ed25519_host_key ] && return

    # If /etc/dropbear is a symlink, delete it.
    [ -L /etc/dropbear ] && rm /etc/dropbear

    # Create directory /etc/dropbear if it does not exist.
    mkdir -p /etc/dropbear

    # Try to copy SSH host key from SD card.
    mkdir -p /mnt/tmp_sdcard
    mount -t vfat -o fmask=0177 -r /dev/mmcblk0p1 /mnt/tmp_sdcard

    if ! cp -p /mnt/tmp_sdcard/dropbear_ed25519_host_key /etc/dropbear ; then
        echo "WARNING: Failed to load SSH host key from SD card" >&2
        umount /mnt/tmp_sdcard
        rmdir /mnt/tmp_sdcard
        exit 1
    fi

    umount /mnt/tmp_sdcard
    rmdir /mnt/tmp_sdcard

    chmod 0600 /etc/dropbear/dropbear_ed25519_host_key
}

case "$1" in
  start)
    start
    ;;
  stop|restart|reload)
    ;;
  *)
    echo "Usage: $0 start"
    exit 1
esac