From: Arnd Bergmann <arnd@xxxxxxxx>
overlapping input and output arguments to snprintf() are
undefined behavior in C99:
drivers/input/joystick/analog.c: In function 'analog_name':
drivers/input/joystick/analog.c:428:3: error: 'snprintf' argument 4 overlaps destination object 'analog' [-Werror=restrict]
428 | snprintf(analog->name, sizeof(analog->name), "%s %d-hat",
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
429 | analog->name, hweight16(analog->mask & ANALOG_HATS_ALL));
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/input/joystick/analog.c:420:40: note: destination object referenced by 'restrict'-qualified argument 1 was declared here
420 | static void analog_name(struct analog *analog)
| ~~~~~~~~~~~~~~~^~~~~~
Change this function to just use the offset it already knows.
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/input/joystick/analog.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/input/joystick/analog.c b/drivers/input/joystick/analog.c
index f798922a4598..8c9fed3f13e2 100644
--- a/drivers/input/joystick/analog.c
+++ b/drivers/input/joystick/analog.c
@@ -419,14 +419,16 @@ static void analog_calibrate_timer(struct analog_port *port)
static void analog_name(struct analog *analog)
{
- snprintf(analog->name, sizeof(analog->name), "Analog %d-axis %d-button",
+ int len;
+
+ len = snprintf(analog->name, sizeof(analog->name), "Analog %d-axis %d-button",
hweight8(analog->mask & ANALOG_AXES_STD),
hweight8(analog->mask & ANALOG_BTNS_STD) + !!(analog->mask & ANALOG_BTNS_CHF) * 2 +
hweight16(analog->mask & ANALOG_BTNS_GAMEPAD) + !!(analog->mask & ANALOG_HBTN_CHF) * 4);
if (analog->mask & ANALOG_HATS_ALL)
- snprintf(analog->name, sizeof(analog->name), "%s %d-hat",
- analog->name, hweight16(analog->mask & ANALOG_HATS_ALL));
+ len += snprintf(analog->name + len, sizeof(analog->name) - len, "%d-hat",
+ hweight16(analog->mask & ANALOG_HATS_ALL));
if (analog->mask & ANALOG_HAT_FCS)
strlcat(analog->name, " FCS", sizeof(analog->name));
--
2.29.2
