Use machinectl shell instead of su

That way it's a real session and systemd is aware of it, so for example user
units get started automatically.

Fixes #18

syschdemd.sh

@@ -20,7 +20,24 @@ if [ ! -e "/run/systemd.pid" ]; then
  LOCALE_ARCHIVE=/run/current-system/sw/lib/locale/locale-archive \
  @daemonize@/bin/daemonize /run/current-system/sw/bin/unshare -fp --mount-proc systemd
  /run/current-system/sw/bin/pgrep -xf systemd > /run/systemd.pid
+
+ # Wait for systemd to start
+ status=1
+ while [[ $status -gt 0 ]]; do
+ $sw/sleep 1
+ status=0
+ $sw/nsenter -t $(< /run/systemd.pid) -p -m -- \
+ $sw/systemctl is-system-running -q --wait 2>/dev/null \
+ || status=$?
+ done
 fi
 
 userShell=$($sw/getent passwd @defaultUser@ | $sw/cut -d: -f7)
-exec $sw/nsenter -t $(< /run/systemd.pid) -p -m --wd="$PWD" -- @wrapperDir@/su -s $userShell @defaultUser@ "$@"
+if [[ $# -gt 0 ]]; then
+ # wsl seems to prefix with "-c"
+ shift
+ cmd="$@"
+else
+ cmd="$userShell"
+fi
+exec $sw/nsenter -t $(< /run/systemd.pid) -p -m -- $sw/machinectl -q --uid=@defaultUser@ shell .host /bin/sh -c "cd \"$PWD\"; exec $cmd"