dotfiles/home/scripts/dmenu_run_systemd

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#!/usr/bin/env bash
# SPDX-License-Identifier: MIT
#
# dmenu_run_systemd: start a program from dmenu as transient systemd .scope
# (C) Copyright Benjamin Block 2021
# (C) Copyright Daniel Olsen 2023
#
# 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 (including the next
# paragraph) 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.
#
# Requirements:
# - Package: bash
# - Package: dmenu
# - dmenu_path
# - dmenu
# - Package: coreutils
# - basenc
# - tr
# - Package: systemd
# - systemd-run
# - Package: util-linux
# - getopt
#
# Usage: dmenu_run_systemd
#
# Start demnu to select program to execute, then start selected program in
# background.
#
# Usage: dmenu_run_systemd [Options] [--] <command> [<arg1>[, <arg2>[...]]]
#
# Start <command> with <arg1..N> without involving dmenu.
# E.g. in i3 config: `bindsym $mod+Return exec dmenu_run_systemd alacritty`.
#
# Options:
# -f, --forground Start <command> as forground task (default: no)
# -p, --pwd Use the current ${PWD} as working directory (default:
# ${HOME})
declare -g prefix forground=false cpwd=false
declare -ga selection
if [ "${#}" -lt 1 ]; then
prefix="dmenu-"
selection=("$(dmenu_path | dmenu)") || exit 127
else
prefix="xrun-"
declare opts
opts="$(getopt --shell bash \
-o "fp" \
-l "forground,pwd" \
-n "dmenu_run_systemd" -- "${@}")" || exit 122
eval set -- "${opts}"
unset opts
while true; do
case "${1}" in
'-f'|'--forground')
forground=true
;;
'-p'|'--pwd')
cpwd=true
;;
'--') shift; break;;
esac
shift
done
selection=("${@}")
fi
readonly selection prefix
declare -g name
# Max unit name length: 256
# - ".scope" - 6
# - "<prefix>-" - 6
# - "-<rand>" - 33
# ------
# "<name>" <= 211
read -r -d '' -n 192 name < <(
echo -n "${selection[*]}" | tr -c 'a-zA-Z0-9_-' '[_*]' || exit 1
echo -e '\0' || exit 2
) || exit 126
readonly name
{ [ "${#name}" -gt 0 ] && [ "${#name}" -le 211 ]; } || exit 125
declare -g rand
# ~5 bits per character => 32*5 = ~160 bits random number
read -r -N 32 rand < <(basenc --base32 < /dev/urandom) || exit 124
readonly rand
[ "${#rand}" -eq 32 ] || exit 123
declare -ga runargs=(
--quiet
--user # run in per-User slice
--scope # create transient `.scope` unit,
# instead of `.service`
--collect # garbage collect everything after run,
# even on failure
--slice="app.slice" # run as part of `app.slice`
--unit="${prefix}${name}-${rand}"
-p MemoryHigh=85%
-p MemoryMax=92%
-p MemorySwapMax=5G
# unit name
--description="dmenu selection ${selection[*]@Q}"
)
if ${cpwd}; then
runargs+=( --working-directory="${PWD:-/}" )
else
runargs+=( --working-directory="${HOME:-/}" )
fi
readonly runargs
## Debugging:
#declare -p prefix selection name rand runargs
if ${forground}; then
systemd-run "${runargs[@]}" -- "${selection[@]}"
else
systemd-run "${runargs[@]}" -- "${selection[@]}" &
fi