[PATCH v2] Input: iqs626a - replace snprintf() with scnprintf()

[PATCH v2] Input: iqs626a - replace snprintf() with scnprintf()

[Jeff LaBundy]

W=1 builds warn that the data written to 'tc_name' is truncated for
theoretical strings such as "channel-2147483646".

Solve this problem by replacing snprintf() with scnprintf() so that
the return value corresponds to what was actually written.

In practice, the largest string that will be written is "channel-8",
and the return value is not actually evaluated. Instead, this patch
ultimately removes the warning without unnecessarily increasing the
size of 'tc_name' from 10 bytes.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202412221136.0S4kRoCC-lkp@intel.com/
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
---
Changes in v2:
 - Fixed commit message ("channel-9" -> "channel-8")

 drivers/input/misc/iqs626a.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/input/misc/iqs626a.c b/drivers/input/misc/iqs626a.c
index 7a6e6927f331..7fba4a8edceb 100644
--- a/drivers/input/misc/iqs626a.c
+++ b/drivers/input/misc/iqs626a.c
@@ -771,7 +771,7 @@ static int iqs626_parse_trackpad(struct iqs626_private *iqs626,
 		u8 *thresh = &sys_reg->tp_grp_reg.ch_reg_tp[i].thresh;
 		char tc_name[10];
 
-		snprintf(tc_name, sizeof(tc_name), "channel-%d", i);
+		scnprintf(tc_name, sizeof(tc_name), "channel-%d", i);
 
 		struct fwnode_handle *tc_node __free(fwnode_handle) =
 				fwnode_get_named_child_node(ch_node, tc_name);
-- 
2.34.1

Re: [PATCH v2] Input: iqs626a - replace snprintf() with scnprintf()

[Dmitry Torokhov]

On Sun, Jan 05, 2025 at 12:56:48PM -0600, Jeff LaBundy wrote:
> W=1 builds warn that the data written to 'tc_name' is truncated for
> theoretical strings such as "channel-2147483646".
> 
> Solve this problem by replacing snprintf() with scnprintf() so that
> the return value corresponds to what was actually written.
> 
> In practice, the largest string that will be written is "channel-8",
> and the return value is not actually evaluated. Instead, this patch
> ultimately removes the warning without unnecessarily increasing the
> size of 'tc_name' from 10 bytes.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202412221136.0S4kRoCC-lkp@intel.com/
> Signed-off-by: Jeff LaBundy <jeff@labundy.com>

Applied, thank you.

-- 
Dmitry