lib/generic/pack: fix operations on empty pack

Several operations were not safe to call on empty pack and would
return invalid memory. If the pack would have reserved space, but
would be empty (length = 0), it's head would be NULL but tail would
be array address (pack->at + 0). This is mostly checked by caller,
but it wasn't in several places (object deletion).

diff --git a/lib/generic/pack.h b/lib/generic/pack.h
index dc7a97591ce20a5d67f1d8a9728957af3045edd1..270630dc5d73d4c0526df6cd56a8ddea9237c8bd 100644 (file)
--- a/lib/generic/pack.h
+++ b/lib/generic/pack.h
@@ -184,6 +184,7 @@ static inline uint8_t *pack_obj_find(pack_t *pack, const uint8_t *obj, pack_objl
                        assert(obj != NULL);
                        return NULL;
                }
+
                uint8_t *endp = pack_tail(*pack);
                uint8_t *it = pack_head(*pack);
                while (it != endp) {
@@ -205,6 +206,7 @@ static inline int pack_obj_del(pack_t *pack, const uint8_t *obj, pack_objlen_t l
                assert(obj != NULL);
                return kr_error(EINVAL);
        }
+
        uint8_t *endp = pack_tail(*pack);
        uint8_t *it = pack_obj_find(pack, obj, len);
        if (it) {