altos/lisp: Append a CRC to the saved image to validate on restore

[fw/altos] / src / lisp / ao_lisp_save.c

diff --git a/src/lisp/ao_lisp_save.c b/src/lisp/ao_lisp_save.c
index 2b19fdcba3520ba182b85799e1c1ea72d9e5cb6b..030846b7234b22197d0340512690cbede9282996 100644 (file)
--- a/src/lisp/ao_lisp_save.c
+++ b/src/lisp/ao_lisp_save.c
@@ -17,12 +17,18 @@
 ao_poly
 ao_lisp_save(struct ao_lisp_cons *cons)
 {
+       if (!ao_lisp_check_argc(_ao_lisp_atom_save, cons, 0, 0))
+               return AO_LISP_NIL;
+
 #ifdef AO_LISP_SAVE
        struct ao_lisp_os_save *os = (struct ao_lisp_os_save *) &ao_lisp_pool[AO_LISP_POOL];
 
        ao_lisp_collect();
-       os->ao_lisp_atoms = ao_lisp_atom_poly(ao_lisp_atoms);
-       os->ao_lisp_globals = ao_lisp_frame_poly(ao_lisp_frame_global);
+       os->atoms = ao_lisp_atom_poly(ao_lisp_atoms);
+       os->globals = ao_lisp_frame_poly(ao_lisp_frame_global);
+       os->const_checksum = ao_lisp_const_checksum;
+       os->const_checksum_inv = ~ao_lisp_const_checksum;
+
        if (ao_lisp_os_save())
                return _ao_lisp_atom_t;
 #endif
@@ -32,13 +38,26 @@ ao_lisp_save(struct ao_lisp_cons *cons)
 ao_poly
 ao_lisp_restore(struct ao_lisp_cons *cons)
 {
+       if (!ao_lisp_check_argc(_ao_lisp_atom_save, cons, 0, 0))
+               return AO_LISP_NIL;
+
 #ifdef AO_LISP_SAVE
+       struct ao_lisp_os_save save;
        struct ao_lisp_os_save *os = (struct ao_lisp_os_save *) &ao_lisp_pool[AO_LISP_POOL];
 
+       if (!ao_lisp_os_restore_save(&save, AO_LISP_POOL))
+               return ao_lisp_error(AO_LISP_INVALID, "header restore failed");
+
+       if (save.const_checksum != ao_lisp_const_checksum ||
+           save.const_checksum_inv != (uint16_t) ~ao_lisp_const_checksum)
+       {
+               return ao_lisp_error(AO_LISP_INVALID, "image is corrupted or stale");
+       }
+
        if (ao_lisp_os_restore()) {
 
-               ao_lisp_atoms = ao_lisp_poly_atom(os->ao_lisp_atoms);
-               ao_lisp_frame_global = ao_lisp_poly_frame(os->ao_lisp_globals);
+               ao_lisp_atoms = ao_lisp_poly_atom(os->atoms);
+               ao_lisp_frame_global = ao_lisp_poly_frame(os->globals);
 
                /* Clear the eval global variabls */
                ao_lisp_eval_clear_globals();