[Qemu-devel] [PATCH v3 4/5] migration: Use QEMU_NONSTRING for non NUL-terminated arrays

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

GCC 8 added a -Wstringop-truncation warning:

  The -Wstringop-truncation warning added in GCC 8.0 via r254630 for
  bug 81117 is specifically intended to highlight likely unintended
  uses of the strncpy function that truncate the terminating NUL
  character from the source string.

This new warning leads to compilation failures:

    CC      migration/global_state.o
  qemu/migration/global_state.c: In function 'global_state_store_running':
  qemu/migration/global_state.c:45:5: error: 'strncpy' specified bound 100 equals destination size [-Werror=stringop-truncation]
       strncpy((char *)global_state.runstate, state, sizeof(global_state.runstate));
       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  make: *** [qemu/rules.mak:69: migration/global_state.o] Error 1

Use the QEMU_NONSTRING attribute, since this array is intended to store
character arrays that do not necessarily contain a terminating NUL.

Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 migration/global_state.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/migration/global_state.c b/migration/global_state.c
index 8e8ab5c51e..6e19333422 100644
--- a/migration/global_state.c
+++ b/migration/global_state.c
@@ -21,7 +21,7 @@
 
 typedef struct {
     uint32_t size;
-    uint8_t runstate[100];
+    uint8_t runstate[100] QEMU_NONSTRING;
     RunState state;
     bool received;
 } GlobalState;
-- 
2.17.2