autoconnector.sh

#!/bin/bash

PROGNAME=$(basename $0)

is_mapping_file=false
ignore_sound=false
ignore_ssh=false


function main() {
  check

  # connects devices
  if ! $is_mapping_file; then # attempts to connect all devices
    bluetoothctl -- list | while read line
    do
      adapter=`echo $line | sed -r 's/^.*(([0-9A-F]{2}:){5}[0-9A-F]{2}).*$/\1/'`

      paired_devices | while read device
      do
        if [[ $(is_connected) = "no" ]]; then
          {
            printf "select $adapter\n\n"
            printf "power on\n\n"
            # sleep 2
            printf "connect $device\n\n"
            # sleep 4
          } | bluetoothctl

          echo
        fi
      done
    done
  else # attempts to connect specific devices written in mapping list
    while read line
    do
      # skip a comment line and a blank line
      if ! [[ $line =~ ^# ]] && ! [[ $line =~ ^([[:blank:]]+.*)*$ ]]; then
        # save Bluetooth adapter’s BD address and device’s BD address
        adapter=`echo "$line," | cut -d ',' -f 1`
        device=`echo "$line," | cut -d ',' -f 2`

        # connect the device if not connected
        if [[ $(is_connected) = "no" ]]; then
          {
            printf "select $adapter\n\n"
            printf "connect $device\n\n"
          } | bluetoothctl
        fi
      fi
    done < $FILE
  fi
}


# returns devices’ BD addresses paired with selected adapter
function paired_devices() {
  {
    printf "select $adapter\n\n"
    printf "paired-devices\n\n"
  } | bluetoothctl | grep "Device " | sed -r 's/^.*(([0-9A-F]{2}:){5}[0-9A-F]{2}).*$/\1/'
}


# checks if the device is being connected
# returns 'yes' or 'no'
function is_connected() {
  {
    printf "select $adapter\n\n"
    printf "info $device\n\n"
  } | bluetoothctl | grep "Connected: " | sed -e 's/Connected: //' | sed -e 's/^[[:blank:]]*//'
}


# checks whether some devices play sound or not
# returns integer of 0 or more (the number of devices playing sound)
function is_playing() {
  # PULSE_RUNTIME_PATH environment variable is necessary
  # crontab does not recognize the PulseAudio daemon if PULSE_RUNTIME_PATH is missing
  #
  # Error message:
  #   pacmd:
  #     No PulseAudio daemon running, or not running as session daemon.
  #   pactl:
  #     Connection failure: Connection refused
  #     pa_context_connect() failed: Connection refused
  #
  # cf. https://superuser.com/questions/1207581/pacmd-why-doesnt-it-work-from-cron#answer-1243363
  export PULSE_RUNTIME_PATH="/run/user/$(id -u)/pulse/"

  # count the number of devices that play sound except for dummy sound
  # Both pacmd or pactl are fine
  # pacmd list-sink-inputs | grep -c "state: RUNNING" ...
  pactl list sink-inputs                                                            |
    grep -e "Corked: " -e "media\.role = " -e "media\.name = "                      |
    tr -d '\n'                                                                      |
    grep -co "Corked: no\s*media\.role = \"music\"\s*media\.name = \"Loopback from"
}


# checks whether some users are logged in now via SSH
# if yes, skip connecting via cron because the machine response is very slow while operating via SSH
function is_logged_in() {
  # https://www.golinuxcloud.com/list-check-active-ssh-connections-linux/
  if [[ $(w -hs | awk '{ print $3 }' | grep -Ev '^-$') != "" ]]; then
    echo true
  else
    echo false
  fi
}


function check() {
  abort_flag=false

  if ! $ignore_sound && [[ $(is_playing) -gt 0 ]]; then
    echo -e "Error: Some devices now playing musics" >&2
    echo -e "       Specify option --ignore-sound to ignore devices playing musics" >&2
    abort_flag=true
  fi

  if ! $ignore_ssh && [[ $(is_logged_in) = "true" ]]; then
    echo -e "Error: Some users now logged in via SSH" >&2
    echo -e "       Specify option --ignore-ssh to ignore SSH connection" >&2
    abort_flag=true
  fi

  if $abort_flag; then
    exit 2
  fi
}


function usage() {
  echo -e "Usage: $PROGNAME [-h]"
  printf  "       %${#PROGNAME}s [-f FILE]\n"
  echo
  echo -e "Description:"
  echo -e "  Attempt to connect all paired Bluetooth devices"
  echo
  echo -e "Options:"
  echo -e "  -h, --help"
  echo -e "    Show this help message and exit"
  echo -e "  -f FILE, --file FILE"
  echo -e "    Attempt to connect only specific devices written in mapping list file"
  echo -e "    For details on how to write a mapping list file, see list.sample"
  echo -e "  --ignore-sound"
  echo -e "    Ignore devices playing sounds"
  echo -e "    When some devices that have already connected to Bluetooth adapters are playing sounds,"
  echo -e "    bluetoothctl attempts to connect other device, and then the sounds breaks up temporarily"
  echo -e "    To avoid this, this script does not connect any device by default"
  echo -e "    when some devices that have already connected to Bluetooth adapters are playing sounds"
  echo -e "  --ignore-ssh"
  echo -e "    Ignore SSH connection"
}


for opt in "$@"
do
  case "$opt" in
    '-h' | '--help' )
      usage
      exit 0
    ;;
    '--ignore-sound' )
      ignore_sound=true
      shift 1
    ;;
    '--ignore-ssh' )
      ignore_ssh=true
      shift 1
    ;;
    '-f' | '--file' )
      if [[ -z "$2" ]] || [[ "$2" =~ ^-+ ]]; then
        echo "$PROGNAME: option requires an argument -- $1" 1>&2
        exit 1
      fi
      FILE=$2
      is_mapping_file=true
      shift 2
    ;;
    '--' | '-' )
      shift 1
      param+=( "$@" )
      break
    ;;
    -* )
      echo "$PROGNAME: illegal option -- '$(echo $1 | sed 's/^-*//')'" 1>&2
      exit 1
    ;;
    * )
      if [[ ! -z "$1" ]] && [[ ! "$1" =~ ^-+ ]]; then
        param+=( "$1" )
        shift 1
      fi
    ;;
  esac
done

main