Changeset 69511176 in mainline for uspace/lib/c/include/adt/list.h

Timestamp:

2021-06-25T15:28:41Z (3 years ago)

Author:

Martin Decky <martin@…>

Branches:

master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

bb14312

Parents:

f5819ca1

Message:

Avoid undefined behavior even more

While the previous implementation no longer suffers from undefined
behavior due to unaligned pointer value, it is still problematic due to
indexing beyond a hypothetical array bound. The assignment of
sizeof(itype) is both an aligned value and does not violate any bounds.

File:

• uspace/lib/c/include/adt/list.h (modified) (2 diffs)

uspace/lib/c/include/adt/list.h

@@ -89 +89 @@
 
 #define list_foreach(list, member, itype, iterator) \
-        for (itype *iterator = NULL; iterator == NULL; iterator = &((itype *) NULL)[1]) \
+        for (itype *iterator = NULL; iterator == NULL; iterator = (itype *) sizeof(itype)) \
                 for (link_t *_link = (list).head.next; \
                     iterator = list_get_instance(_link, itype, member), \
@@ -95 +95 @@
 
 #define list_foreach_rev(list, member, itype, iterator) \
-        for (itype *iterator = NULL; iterator == NULL; iterator = &((itype *) NULL)[1]) \
+        for (itype *iterator = NULL; iterator == NULL; iterator = (itype *) sizeof(itype)) \
                 for (link_t *_link = (list).head.prev; \
                     iterator = list_get_instance(_link, itype, member), \