Re: [Qemu-devel] [PATCH v2 0/3] Fix strncpy() warnings for GCC8 new -Wstringop-truncation

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

On Tue, Dec 18, 2018 at 12:03:30PM +0100, Philippe Mathieu-Daudé wrote:
> GCC 8 new warning prevents builds to success since quite some time.
> First report on the mailing list is in July 2018:
> https://lists.gnu.org/archive/html/qemu-devel/2018-07/msg03723.html
> 
> Various intents has been sent to fix this:
> - Incorrectly using g_strlcpy()
>   https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg03705.html
>   https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg03706.html
> - Using assert() and strpadcpy()
>   https://lists.gnu.org/archive/html/qemu-devel/2018-11/msg03938.html
> - Use #pragma GCC diagnostic ignored "-Wstringop-truncation"
>   https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg04261.html
> - adding an inline wrapper with said pragma in there
>   https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg04261.html
> - -Wno-stringop-truncation is the makefile
>   https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg04261.html
> 
> This series replace the strncpy() calls by strpadcpy() which seemed
> to me the saniest option.
> 
> Regards,
> 
> Phil.

Do you happen to know why does it build fine with
Gcc 8.2.1?

Reading the GCC manual it seems that
there is a "nostring" attribute that means
"might not be 0 terminated".
I think we should switch to that which fixes the warning
but also warns if someone tries to misuse these
as C-strings.

Seems to be a better option, does it not?


> Marc-André Lureau (1):
>   hw/acpi: Replace strncpy() by strpadcpy(pad='\0')
> 
> Philippe Mathieu-Daudé (2):
>   block/sheepdog: Replace strncpy() by strpadcpy(pad='\0')
>   migration: Replace strncpy() by strpadcpy(pad='\0')
> 
>  block/sheepdog.c         |  6 +++---
>  hw/acpi/aml-build.c      |  6 ++++--
>  hw/acpi/core.c           | 13 +++++++------
>  migration/global_state.c |  4 ++--
>  4 files changed, 16 insertions(+), 13 deletions(-)
> 
> -- 
> 2.17.2