On Tue, Dec 18, 2018 at 3:09 PM Philippe Mathieu-Daudé
<email address hidden> wrote:
>
> 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
>
> The runstate name doesn't require the strings to be NUL-terminated,
> therefore strncpy is the right function to use here.
>
> We could add a #pragma GCC diagnostic ignored "-Wstringop-truncation"
> around, disable the warning globally using -Wno-stringop-truncation,
> but since QEMU provides the strpadcpy() which does the same purpose,
> simply use it to avoid the annoying warning.
>
> Signed-off-by: Philippe Mathieu-Daudé <email address hidden>
On Tue, Dec 18, 2018 at 3:09 PM Philippe Mathieu-Daudé truncation warning: truncation warning added in GCC 8.0 via r254630 for global_ state.o global_ state.c: In function 'global_ state_store_ running' : global_ state.c: 45:5: error: 'strncpy' specified bound 100 equals destination size [-Werror= stringop- truncation] state.runstate, state, sizeof( global_ state.runstate) ); ~~~~~~~ ~~~~~~~ ~~~~~~~ ~~~~~~~ ~~~~~~~ ~~~~~~~ ~~~~~~~ ~~~~~~~ ~~~~~~~ ~~~~~~ global_ state.o] Error 1 truncation" truncation,
<email address hidden> wrote:
>
> GCC 8 added a -Wstringop-
>
> The -Wstringop-
> 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/
> qemu/migration/
> qemu/migration/
> strncpy((char *)global_
> ^~~~~~~
> make: *** [qemu/rules.mak:69: migration/
>
> The runstate name doesn't require the strings to be NUL-terminated,
> therefore strncpy is the right function to use here.
>
> We could add a #pragma GCC diagnostic ignored "-Wstringop-
> around, disable the warning globally using -Wno-stringop-
> but since QEMU provides the strpadcpy() which does the same purpose,
> simply use it to avoid the annoying warning.
>
> Signed-off-by: Philippe Mathieu-Daudé <email address hidden>
Reviewed-by: Marc-André Lureau <email address hidden>
> --- global_ state.c | 4 ++-- global_ state.c b/migration/ global_ state.c .c7e7618118 100644 global_ state.c global_ state.c state_store( void) state_store_ running( void) str(RUN_ STATE_RUNNING) ; state.runstate, global_ state.runstate) ); state.runstate, global_ state.runstate) , state, '\0'); state_received( void)
> migration/
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/migration/
> index 8e8ab5c51e.
> --- a/migration/
> +++ b/migration/
> @@ -42,8 +42,8 @@ int global_
> void global_
> {
> const char *state = RunState_
> - strncpy((char *)global_
> - state, sizeof(
> + strpadcpy((char *)global_
> + sizeof(
> }
>
> bool global_
> --
> 2.17.2
>
>
--
Marc-André Lureau