systemctl

#!/bin/bash
# The MIT License (MIT)
# 
# Copyright © 2022 
# 
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the “Software”), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

set -e

self="$(realpath "$0")"

if [ "$(id -u)" != 0 ]
then
  pkexec "$self" "$@"
  exit $?
fi

declare -A short_opts=(

  [t]=type
  [p]=property
  [s]=signal
  [n]=lines
  [o]=output
  [H]=host
  [M]=machine
  [a]=all
  [r]=recursive
  [l]=full
  [T]=showtransaction
  [q]=quiet
  [f]=force
  [h]=help

)

declare -A option_argcount=(

  [type]=1
  [state]=1
  [property]=1
  [jobmode]=1
  [checkinhibitors]=1
  [killwho]=1
  [signal]=1
  [what]=1
  [message]=1
  [root]=1
  [presetmode]=1
  [lines]=1
  [output]=1
  [bootloadermenu]=1
  [bootloaderentry]=1
  [rebootargument]=1
  [timestamp]=1
  [host]=1
  [machine]=1
  [legend]=1

  [P]=0
  [all]=0
  [recursive]=0
  [reverse]=0
  [after]=0
  [before]=0
  [withdependencies]=0
  [full]=0
  [value]=0
  [showtypes]=0
  [showtransaction]=0
  [fail]=0
  [i]=0
  [dryrun]=0
  [quiet]=0
  [noblock]=0
  [wait]=0
  [user]=0
  [system]=0
  [failed]=0
  [nowall]=0
  [global]=0
  [noreload]=0
  [noaskpassword]=0
  [force]=0
  [now]=0
  [runtime]=0
  [firmwaresetup]=0
  [plain]=0
  [mkdir]=0
  [marked]=0
  [readonly]=0
  [nopager]=0
  [help]=0
  [version]=0

)

declare -A opts
args=()

die(){
  printf "%s\n" "$*" >&2
  exit 1
}

read_kv(){
  if [[ "$1" == *=* ]]
  then
    has_value=1
    IFS== read -r key value <<<"$1"
  else
    has_value=0
    value=
    key="$1"
  fi
}

pre_shift(){
  if [ "$1" = 0 ]
    then die "$2"
  fi
}

function_exists(){
  if [[ "$(type -t "$1")" == function ]]
    then return 0
    else return 1
  fi
}

key=
value=
has_value=
while [ $# -gt 0 ]
do
  arg="$1"; shift
  case "$arg" in
    --*)
        read_kv "${arg:2}"
        count="${option_argcount["$key"]}"
        if ! [ -n "$count" ]
          then die "systemctl: unrecognized option  '--$key'"
        fi
        if [ "$has_value" = 1 ] && [ "$count" = 0 ]
          then die "Option --$key doesn't take an argument"
        fi
        if [ "$has_value" = 0 ] && [ "$count" -gt 0 ]
          then value="$1"; pre_shift "$#" "systemctl: option requires an argument --  '$key'"; shift
        fi
        value=("$value")
        while [ "$count" -gt "${#value[@]}" ]
          do value+=("$1"); pre_shift "$#" "systemctl: option requires an argument --  '$key'"; shift
        done
        opts["$key"]="${value[*]}"
        value=
      ;;
    -*)
        read_kv "${arg:1}"
        i=0
        while [ "$i" -lt "${#key}" ]
        do
          k="${key[i]}"
          i=$((i + 1))
          name="${short_opts["$k"]}"
          if ! [ -n "$name" ]
            then echo "systemctl: unrecognized option  '-$k'"
          fi
          count="${option_argcount["$name"]}"
          if ! [ -n "$count" ]
            then die "systemctl: unrecognized option  '-$k'/'--$name'"
          fi
          if [ "$has_value" = 1 ] && [ "$count" = 0 ]
            then die "Option --$name doesn't take an argument"
          fi
          if [ "$has_value" = 0 ] && [ "$count" -gt 0 ]
            then value="$1"; pre_shift "$#" "systemctl: option requires an argument --  '$k'/'$name'"; shift
          fi
          value=("$value")
          while [ "$count" -gt "${#value[@]}" ]
            do value+=("$1"); pre_shift "$#" "systemctl: option requires an argument --  '$k'/'$name'"; shift
          done
          opts["$name"]="${value[*]}"
          value=
          has_value=0
        done
      ;;
    *) args+=("$arg") ;;
  esac
done
unset key value has_value

if [ "${#args[@]}" = 0 ]
  then args=( list-units )
fi

service_file=
unit_type=
unit=

parse_unit(){
  unit_type=service
  service_file=
  if [[ "$1" == *\.* ]]
    then IFS='.' read -r unit unit_type <<<"$1"
    else unit="$1"
  fi
  if [ "$unit_type" = service ] && [ -x "/etc/init.d/$unit" ]
    then service_file="/etc/init.d/$unit"
  fi
}

systemctl_halt(){
  halt
}

systemctl_poweroff(){
  poweroff
}

systemctl_reboot(){
  reboot
}

systemctl_start(){
  [ $# != 0 ] || die "Too few arguments"
  ret=0
  while [ $# != 0 ]
  do
    parse_unit "$1"; shift
    if ! [ "$unit_type" = service ]
    then
      echo "Unsupported unit type" >&2
      continue
    fi
    if ! service "$unit" start
      then ret=3
    fi
  done
  return $ret
}

systemctl_stop(){
  ret=0
  [ $# != 0 ] || die "Too few arguments"
  while [ $# != 0 ]
  do
    parse_unit "$1"; shift
    if ! [ "$unit_type" = service ]
    then
      echo "Unsupported unit type" >&2
      continue
    fi
    if ! service "$unit" stop
      then ret=3
    fi
  done
  return $ret
}

systemctl_reload(){
  [ $# != 0 ] || die "Too few arguments"
  ret=0
  while [ $# != 0 ]
  do
    parse_unit "$1"; shift
    if ! [ "$unit_type" = service ]
    then
      echo "Unsupported unit type" >&2
      continue
    fi
    if ! service "$unit" force-reload || service "$unit" reload
      then ret=3
    fi
  done
  return $ret
}

systemctl_restart(){
  [ $# != 0 ] || die "Too few arguments"
  while [ $# != 0 ]
  do
    parse_unit "$1"; shift
    if ! [ "$unit_type" = service ]
    then
      echo "Unsupported unit type" >&2
      continue
    fi
    if ! service "$unit" restart
      then return $?
    fi
  done
}

systemctl_try-restart(){
  systemctl_restart "$@"
  return $?
}

systemctl_reload-or-restart(){
  [ $# != 0 ] || die "Too few arguments"
  while [ $# != 0 ]
  do
    parse_unit "$1"; shift
    [ "$unit_type" = service ] || die "Unsupported unit type"
    if service "$unit" status &>/dev/null
    then
      if ! systemctl_reload "$1" || systemctl_restart "$1"
        then return $?
      fi
    fi
  done
}
systemctl_try-reload-or-restart(){
  [ $# != 0 ] || die "Too few arguments"
  while [ $# != 0 ]
  do
    parse_unit "$1"; shift
    [ "$unit_type" = service ] || die "Unsupported unit type"
    if ! systemctl_reload-or-restart "$@"
      then return $?
    fi
  done
}

systemctl_is-active(){
  [ $# != 0 ] || die "Too few arguments"
  ret=0
  while [ $# != 0 ]
  do
    parse_unit "$1"; shift
    if ! [ "$unit_type" = service ]
    then
      echo "Unsupported unit type"
      ret=3
    fi
    if service "$unit" status &>/dev/null
    then
      echo active
    else
      echo inactive
      ret=3
    fi
  done
  return $ret
}

systemctl_status(){
  if [ $# = 0 ]
  then
    service --status-all
    return $?
  else
    ret=0
    while [ $# != 0 ]
    do
      parse_unit "$1"; shift
      if ! active="$(systemctl_is-active "$unit.$unit_type")"
        then ret=3
      fi
      if [ -n "$service_file" ]
        then loaded="loaded ($service_file)"
        else loaded="not-found"
      fi
      printf "• %s\n   loaded: %s\n   Active: %s\n\n" "$unit.$unit_type" "$loaded" "$active"
    done
    return $ret
  fi
}

systemctl_enable(){
  while [ $# != 0 ]
  do
    parse_unit "$1"; shift
    if ! [ "$unit_type" = service ]
    then
      echo "Unsupported unit type" >&2
      continue
    fi
    update-rc.d "$unit" defaults
    update-rc.d "$unit" enable
  done
  return 0
}

systemctl_disable(){
  while [ $# != 0 ]
  do
    parse_unit "$1"; shift
    if ! [ "$unit_type" = service ]
    then
      echo "Unsupported unit type" >&2
      continue
    fi
    update-rc.d "$unit" defaults-disabled
    update-rc.d "$unit" disable
  done
  return 0
}

systemctl_reenable(){
  systemctl_enable "$@"
  return $?
}

systemctl_is-enabled(){ echo >&2 "operation is-enabled is not implemented yet"; }


systemctl_list-units(){ echo >&2 "operation list-units is not implemented yet"; }
systemctl_list-sockets(){ echo >&2 "operation list-sockets is not implemented yet"; }
systemctl_list-timers(){ echo >&2 "operation list-timers is not implemented yet"; }
systemctl_is-failed(){ echo >&2 "operation is-failed is not implemented yet"; }
systemctl_show(){ echo >&2 "operation show is not implemented yet"; }
systemctl_cat(){ echo >&2 "operation cat is not implemented yet"; }
systemctl_help(){ echo >&2 "operation help is not implemented yet"; }
systemctl_list-dependencies(){ echo >&2 "operation list-dependencies is not implemented yet"; }
systemctl_isolate(){ echo >&2 "operation isolate is not implemented yet"; }
systemctl_kill(){ echo >&2 "operation kill is not implemented yet"; }
systemctl_clean(){ echo >&2 "operation clean is not implemented yet"; }
systemctl_freeze(){ echo >&2 "operation freeze is not implemented yet"; }
systemctl_thaw(){ echo >&2 "operation thaw is not implemented yet"; }
systemctl_set-property(){ echo >&2 "operation set-property is not implemented yet"; }
systemctl_bind(){ echo >&2 "operation bind is not implemented yet"; }
systemctl_mount-image(){ echo >&2 "operation mount-image is not implemented yet"; }
systemctl_service-log-level(){ echo >&2 "operation service-log-level is not implemented yet"; }
systemctl_service-log-target(){ echo >&2 "operation service-log-target is not implemented yet"; }
systemctl_reset-failed(){ echo >&2 "operation reset-failed is not implemented yet"; }
systemctl_list-unit-files(){ echo >&2 "operation list-unit-files is not implemented yet"; }
systemctl_preset(){ echo >&2 "operation preset is not implemented yet"; }
systemctl_preset-all(){ echo >&2 "operation preset-all is not implemented yet"; }
systemctl_mask(){ echo >&2 "operation mask is not implemented yet"; }
systemctl_unmask(){ echo >&2 "operation unmask is not implemented yet"; }
systemctl_link(){ echo >&2 "operation link is not implemented yet"; }
systemctl_revert(){ echo >&2 "operation revert is not implemented yet"; }
systemctl_add-wants(){ echo >&2 "operation add-wants is not implemented yet"; }
systemctl_edit(){ echo >&2 "operation edit is not implemented yet"; }
systemctl_get-default(){ echo >&2 "operation get-default is not implemented yet"; }
systemctl_set-default(){ echo >&2 "operation set-default is not implemented yet"; }
systemctl_list-machines(){ echo >&2 "operation list-machines is not implemented yet"; }
systemctl_list-jobs(){ echo >&2 "operation list-jobs is not implemented yet"; }
systemctl_cancel(){ echo >&2 "operation cancel is not implemented yet"; }
systemctl_show-environment(){ echo >&2 "operation show-environment is not implemented yet"; }
systemctl_set-environment(){ echo >&2 "operation set-environment is not implemented yet"; }
systemctl_unset-environment(){ echo >&2 "operation unset-environment is not implemented yet"; }
systemctl_import-environment(){ echo >&2 "operation import-environment is not implemented yet"; }
systemctl_daemon-reload(){ echo >&2 "operation daemon-reload is not implemented yet"; }
systemctl_daemon-reexec(){ echo >&2 "operation daemon-reexec is not implemented yet"; }
systemctl_log-level(){ echo >&2 "operation log-level is not implemented yet"; }
systemctl_log-target(){ echo >&2 "operation log-target is not implemented yet"; }
systemctl_service-watchdogs(){ echo >&2 "operation service-watchdogs is not implemented yet"; }
systemctl_is-system-running(){ echo >&2 "operation is-system-running is not implemented yet"; }
systemctl_default(){ echo >&2 "operation default is not implemented yet"; }
systemctl_rescue(){ echo >&2 "operation rescue is not implemented yet"; }
systemctl_emergency(){ echo >&2 "operation emergency is not implemented yet"; }
systemctl_kexec(){ echo >&2 "operation kexec is not implemented yet"; }
systemctl_exit(){ echo >&2 "operation exit is not implemented yet"; }
systemctl_switch-root(){ echo >&2 "operation switch-root is not implemented yet"; }
systemctl_suspend(){ echo >&2 "operation suspend is not implemented yet"; }
systemctl_hibernate(){ echo >&2 "operation hibernate is not implemented yet"; }
systemctl_hybrid-sleep(){ echo >&2 "operation hybrid-sleep is not implemented yet"; }
systemctl_suspend-then-hibernate(){ echo >&2 "operation suspend-then-hibernate is not implemented yet"; }

set +e
if function_exists "systemctl_${args[0]}"
  then "systemctl_${args[0]}" "${args[@]:1}"
  else die "Unknown operation ${args[0]}"
fi

exit $?