Re: [Qemu-devel] [Qemu-trivial] [PATCH] jazz_led: fix bad snprintf

[Laurent Vivier <lvivier@redhat.com>]

On 03/05/2017 12:44, Paolo Bonzini wrote:
> 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,

Reviewed-by: Laurent Vivier <lvivier@redhat.com>