prep.sh

#!/bin/bash

#    prep.sh - prepare device for execution of phone_home.sh at boot
#
#    Copyright (C) 2019  scip AG
#
#    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 3 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, see <https://www.gnu.org/licenses/>.

helptext="Usage: prep.sh <options>

Options:
 -o, --overwrite    overwrite configuration files even if they exist (default:
                    do not overwrite)
 -c, --config       config file to use (default: \"config.sh\" in the directory
                    the script resides in)
 -h, --help         print this help text and exit"

# set default config file
_config="$(dirname "$(readlink -f "$0")")/config.sh"

overwrite=0
for ((i=1; i<=$#; i++)); do
    case ${!i} in
        -o|--overwrite) overwrite=1;;
        -c|--config)    ((i++)); _config="${!i}";;
        -h|--help)      echo "$helptext"; exit 0;;
        *) echo "Unknown argument: ${!i@Q}" >&2; exit 1;;
    esac
done

((UID == 0 || EUID == 0)) || { echo "Script needs root permissions to install packages and write config files" >&2; exit 1; }

apt install udhcpd hostapd hping3 ncat iptables usb-modeswitch

if [[ -r "$_config" ]]; then
    source "$_config"
else
    echo "Config file ${_config@Q} does not exist or is not readable" >&2
    exit 1
fi

[[ -d "$UDHCPD_DIR" ]] || mkdir -pm 755 "$UDHCPD_DIR"

if [[ -f "$UDHCPD_DIR/$UDHCPD_FILE" && "$overwrite" -eq 0 ]]
then
    echo "$UDHCPD_DIR/$UDHCPD_FILE exists; will not overwrite"
else
    printf "%s" "$UDHCPD_CONF" >"$UDHCPD_DIR/$UDHCPD_FILE"
fi

[[ -d "$HOSTAPD_DIR" ]] || mkdir -pm 755 "$HOSTAPD_DIR"

if [[ -f "$HOSTAPD_DIR/$HOSTAPD_FILE" && "$overwrite" -eq 0 ]]
then
    echo "$HOSTAPD_DIR/$HOSTAPD_FILE exists, will not overwrite"
else
    printf "%s" "$HOSTAPD_CONF" >"$HOSTAPD_DIR/$HOSTAPD_FILE"
fi

[[ -d "$UNIT_FILE_DIR" ]] || { echo "Systemd directory not found: $UNIT_FILE_DIR" >&2; exit 1; }

if [[ -f "$UNIT_FILE_DIR/$UNIT_FILE_NAME" && "$overwrite" -eq 0 ]]
then
    echo "$UNIT_FILE_DIR/$UNIT_FILE_NAME exists, will not overwrite"
    echo "Make sure the path to the phone_home script in the unit file is correct"
else
    printf "%s" "$UNIT_FILE_CONF" >"$UNIT_FILE_DIR/$UNIT_FILE_NAME"
fi

systemctl enable "$UNIT_FILE_NAME"