sane-vpn: allow sane-vpn do to work with no additional arguments

pkgs/additional/sane-scripts/src/sane-vpn

@@ -9,9 +9,9 @@ usageDescription() {
   echo "however, systemd --user has poor support for capabilities, hence this here is a bespoke script instead of a service"
   echo ""
   echo "usage:"
-  echo "sane-vpn up REGION"
-  echo "sane-vpn down REGION"
-  echo "sane-vpn do REGION COMMAND [COMMAND ARGS ...]"
+  echo "sane-vpn up [REGION]"
+  echo "sane-vpn down [REGION]"
+  echo "sane-vpn do [REGION [COMMAND ...] ]"
   echo "sane-vpn help"
 }
 
@@ -70,7 +70,7 @@ canonicalizeRegion() {
 }
 
 vpnToggle() {
-  verb="$1"
+  local verb="$1"
 
   debug "vpnToggle with:"
   debug "  id='$id'"
@@ -95,12 +95,17 @@ vpnDo() {
   debug "  name='$name'"
   debug "  addrV4='$addrV4'"
   debug "  dns='$dns'"
-  sanebox --sanebox-method pastaonly --sanebox-net-dev "$name" --sanebox-net-gateway "$addrV4" --sanebox-dns "$dns" "$@"
+  local cmd=("$@")
+  if [ ${#cmd} -eq 0 ]; then
+    cmd=(/bin/sh)
+  fi
+  debug "cmd: ${cmd[*]}"
+  sanebox --sanebox-method pastaonly --sanebox-net-dev "$name" --sanebox-net-gateway "$addrV4" --sanebox-dns "$dns" "${cmd[@]}"
 }
 
 usage() {
-  rc="$1"
-  msg="$2"
+  local rc="$1"
+  local msg="$2"
 
   test -n "$msg" && echo "$msg"
 
@@ -115,16 +120,16 @@ usage() {
 }
 
 parseCli() {
-  _oper="$1"
+  local oper="$1"
   shift
   region="$1"
-  shift
+  shift || true
 
   getVpns
   canonicalizeRegion
   sourceVpn "$region"
 
-  case "$_oper" in
+  case $oper in
     (up)
       vpnToggle add
       ;;
@@ -138,7 +143,7 @@ parseCli() {
       usage 0
       ;;
     (*)
-      usage 1 "invalid operation '$_oper'"
+      usage 1 "invalid operation '$oper'"
       ;;
   esac
 }