Rewrite qubes-i3-sensible-terminal

qubes-i3-sensible-terminal

@@ -1,35 +1,166 @@
-#!/bin/sh
-set -eu
+#!/usr/bin/bash --posix
+
+# Set POSIX-compliant mode to make bash and certain utils more predictable.
+# Bash-specific features are still used, that's intentional
+POSIXLY_CORRECT=1
+set -o posix
+readonly POSIXLY_CORRECT
+export POSIXLY_CORRECT
+
+# Set IFS explicitly. POSIX does not enforce whether IFS should be inherited
+# from the environment, so it's safer to set it explicitly
+IFS=$' \t\n'
+export IFS
+
+# Exit on errors and unset variables
+set -eEu
+
+declare -r GUIVM_TERMINAL="i3-sensible-terminal"
+declare -r DOMU_TERMINAL="qubes-run-terminal"
+declare -r DOMU_CONSOLE="qvm-console-dispvm"
+
+
+print_usage()
+{
+    cat << USAGE >&2
+Usage:  $(basename "$0") [--console] [--user USER]
+
+Options:
+  -h, --help        print this usage information
+  -c, --console     launch disposable console instead of terminal
+  -u, --user        run terminal as specified user
+USAGE
+    return 0
+}
+
 
 main() {
-  cmd=""
-  case "${1-}" in
-    console) cmd="$1";;
-    "");;
-    *) printf '%s\n' "Invalid argument" >&2; exit 1;;
-  esac
-
-  guivm_terminal=i3-sensible-terminal
-  domU_terminal=qubes-run-terminal
-  domU_console=qvm-console-dispvm
-  id="$(xprop -root _NET_ACTIVE_WINDOW)"
-  id="${id##* }"
-  vm="$(xprop -id "$id" | grep '_QUBES_VMNAME(STRING)')" || true
-  if test -z "$vm"; then
-    exec "$guivm_terminal"
-  fi
-  vm="${vm#*\"}"
-  vm="${vm%\"*}"
-
-  if test "$cmd" = "console"; then
-    exec "$domU_console" -- "$vm"
-  fi
-
-  if command -v qrexec-client >/dev/null; then
-    exec qrexec-client -e -d "$vm" -- \
-      "DEFAULT:QUBESRPC qubes.StartApp+$domU_terminal $vm"
-  fi
-  exec qvm-run --no-gui --service -- "$vm" qubes.StartApp+"$domU_terminal"
+    # Get ID of active window
+    local id
+    id="$(xprop -root _NET_ACTIVE_WINDOW)"
+    id="${id##* }"
+    declare -r id
+
+    local vm
+    vm="$(xprop -id "$id" | grep '_QUBES_VMNAME(STRING)')" || true
+
+    if test -z "$vm"
+    then
+        case "$arg_user" in
+            DEFAULT)
+                exec -- "$GUIVM_TERMINAL"
+                ;;
+            *)
+                exec -- sudo -n -u "$arg_user" -- "$GUIVM_TERMINAL"
+                ;;
+        esac
+    fi
+
+    vm="${vm#*\"}"
+    vm="${vm%\"*}"
+    declare -r vm
+
+    # Launch console for VM (hvc)
+    if test "$arg_console" = "true"
+    then
+        exec -- "$DOMU_CONSOLE" -- "$vm"
+    fi
+
+    if command -v qrexec-client >/dev/null
+    then
+        exec -- qrexec-client -e -d "$vm" -- \
+            "$arg_user:QUBESRPC qubes.StartApp+$DOMU_TERMINAL $vm"
+    fi
+
+    # Else, if qrexec-client can't be used (e.g. in a GUIVM), use qvm-run instead
+    case "$arg_user" in
+        DEFAULT)
+            exec qvm-run --no-gui --service -- "$vm" qubes.StartApp+"$DOMU_TERMINAL"
+            ;;
+        *)
+            exec qvm-run --no-gui --service -u "$arg_user" -- "$vm" qubes.StartApp+"$DOMU_TERMINAL"
+            ;;
+    esac
 }
 
-main "$@"
+
+# Adapted from https://stackoverflow.com/a/29754866
+parse_options()
+{
+    declare -g arg_user="DEFAULT"
+    declare -g arg_console=""
+
+    if [ $# -lt 1 ]
+    then
+        return
+    fi
+    # Check whether getopt version is "enhanced"
+    # shellcheck disable=SC2251
+    ! getopt --test >/dev/null
+    if [[ ${PIPESTATUS[0]} -ne 4 ]]
+    then
+        printf '%s\n' 'This script requires getopt enhanced to work properly' >&2
+        exit 2
+    fi
+
+    # Set available options
+    declare -r LONGOPTS=help,console,user:
+    declare -r OPTIONS=hcu:
+
+    # Get arguments from "$@" using getopt
+    IFS=" " read -r -a PARSED <<< "$(getopt --options=$OPTIONS --longoptions=$LONGOPTS --name "$0" -- "$@")"
+    eval set -- "${PARSED[*]}"
+
+    # Write to argument variables
+    while true
+    do
+        case "$1" in
+            -h|--help)
+                print_usage
+                exit 0
+                ;;
+            -u|--user)
+                arg_user="$2"
+                shift 2
+                ;;
+            -c|--console)
+                arg_console="true"
+                shift
+                ;;
+            --)
+                shift
+                break
+                ;;
+            *)
+                printf '%s\n' "$(basename "$0"): Invalid argument" >&2
+                print_usage
+                exit 2
+                ;;
+        esac
+    done
+
+    # Handle positional arguments ($1, $2, …)
+    if [ $# -gt 0 ]
+    then
+        case "${1-}" in
+            console)
+                arg_console="true"
+                printf '%s\n' "$(basename "$0"): Positional arguments are deprecated and will be removed in the future. Use --console instead" >&2
+                ;;
+            *)
+                printf '%s\n' "$(basename "$0"): Invalid argument" >&2
+                print_usage
+                exit 2
+                ;;
+        esac
+    fi
+
+    declare -gr arg_user
+    declare -gr arg_console
+
+    return
+}
+
+
+parse_options "$@"
+main