update TODO

TODO

@@ -24,6 +24,28 @@ Janitorial Clean-ups:
 
 Features:
 
+* list the exit codes from the BSD/glibc <sysexits.h> in our own
+  exit-codes.[ch] tables.
+
+* introduce Ephemeral= unit file switch, that creates an ephemeral copy of all
+  files and directories that are left writable for a unit, and which are
+  removed after the unit goes down again. A bit like --ephemeral for
+  systemd-nspawn but for system services. If used together with RootImage= this
+  should reflink the image file itself.
+
+  Related: add Ephemeral=<path1> <path2> … which would allow marking
+  specific paths only like this.
+
+* when RootImage= is used, mark the loopback device read-only if the other
+  settings permit it (i.e. if ProtectSystem=strict is set, and no directory if
+  the image is writable)
+
+* add CopyFile= or so as unit file setting that may be used to copy files or
+  directory trees from the host to te services RootImage= and RootDirectory=
+  environment. Which we can use for /etc/machine-id and in particular
+  /etc/resolv.conf. Should be smart and do something useful on read-only
+  images, for example fallback to read-only bind mounting the file instead.
+
 * nspawn's console TTY should be allocated from within the container, not
   mounted in from the outside