Paolo Bonzini <pbonz...@redhat.com> writes:
> Detected by GCC 7's -Wformat-truncation. snprintf writes at most
> 2 bytes here including the terminating NUL, so the result is
> truncated. In addition, the newline at the end is pointless.
> Fix the buffer size and the format string.
> ---
> hw/display/jazz_led.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/hw/display/jazz_led.c b/hw/display/jazz_led.c
> index b72fdb1717..3c97d56434 100644
> --- a/hw/display/jazz_led.c
> +++ b/hw/display/jazz_led.c
> @@ -227,13 +227,13 @@ static void jazz_led_invalidate_display(void *opaque)
> static void jazz_led_text_update(void *opaque, console_ch_t *chardata)
> {
> LedState *s = opaque;
> - char buf[2];
> + char buf[3];
>
> dpy_text_cursor(s->con, -1, -1);
> qemu_console_resize(s->con, 2, 1);
>
> /* TODO: draw the segments */
> - snprintf(buf, 2, "%02hhx\n", s->segments);
> + snprintf(buf, 3, "%02hhx", s->segments);
> console_write_ch(chardata++, ATTR2CHTYPE(buf[0], QEMU_COLOR_BLUE,
> QEMU_COLOR_BLACK, 1));
> console_write_ch(chardata++, ATTR2CHTYPE(buf[1], QEMU_COLOR_BLUE,
Since we're only every interested in the first two characters, the
truncation is totally harmless. Thus, your patch cleans doesn't really
"fix bad snprintf", it cleans up an unclean one. Consider rewording the
commit message accordingly.
Regardless,
Reviewed-by: Markus Armbruster <arm...@redhat.com>
