[PATCH] acpi: use constants as strncpy limit

["Michael S. Tsirkin" <mst@redhat.com>]

gcc is not smart enough to figure out length was validated before use as
strncpy limit, resulting in this warning:

inlined from ‘virt_set_oem_table_id’ at ../../hw/arm/virt.c:2197:5:
/usr/include/aarch64-linux-gnu/bits/string_fortified.h:106:10: error:
‘__builtin_strncpy’ specified bound depends on the length of the
source argument [-Werror=stringop-overflow=]

Simplify things by using a constant limit instead.

Fixes: 97fc5d507fca ("acpi: Permit OEM ID and OEM table ID fields to be changed")
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/arm/virt.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index ecb0e14816..f538194e32 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2107,7 +2107,7 @@ static void virt_set_oem_id(Object *obj, const char *value, Error **errp)
         return;
     }
 
-    strncpy(vms->oem_id, value, len + 1);
+    strncpy(vms->oem_id, value, 6);
 }
 
 static char *virt_get_oem_table_id(Object *obj, Error **errp)
@@ -2128,7 +2128,7 @@ static void virt_set_oem_table_id(Object *obj, const char *value,
                    "User specified oem-table-id value is bigger than 8 bytes in size");
         return;
     }
-    strncpy(vms->oem_table_id, value, len + 1);
+    strncpy(vms->oem_table_id, value, 8);
 }
 
 
-- 
MST