[PATCH v4] media: siano: Replace strlcat() with scnprintf() in sms_ir_init()

[Mariia Nikitash <nikitash.mariiaw@gmail.com>]

In preparation for removing the deprecated strlcat() API[1], replace
the strscpy() and strlcat() calls with a single bounded scnprintf()
call to construct the IR device path.

This preserves the original NUL-terminated output, including partial
or omitted "/ir0" suffixes when the 32-byte buffer is too small.

Link: https://github.com/KSPP/linux/issues/370 [1]
Signed-off-by: Mariia Nikitash <nikitash.mariiaw@gmail.com>
---
Changes in v4:
- Replace seq_buf with scnprintf(), as suggested by David Laight
  and Kees Cook.
- Remove the unused seq_buf include and local variable.

Changes in v3:
- Replace snprintf() with seq_buf operations after reproducing
  the GCC -Wformat-truncation warning noted by David Laight.
- Drop the previous Reviewed-by tags due to the implementation change.

Changes in v2:
- No code changes.
- Remove the statement about buffer capacities from the commit message.
- Add Reviewed-by tags from Alejandro Colomar and Shihuang Liu.

 drivers/media/common/siano/smsir.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/common/siano/smsir.c b/drivers/media/common/siano/smsir.c
index 283770d583d5..6952871c5816 100644
--- a/drivers/media/common/siano/smsir.c
+++ b/drivers/media/common/siano/smsir.c
@@ -55,8 +55,8 @@ int sms_ir_init(struct smscore_device_t *coredev)
 	snprintf(coredev->ir.name, sizeof(coredev->ir.name),
 		 "SMS IR (%s)", sms_get_board(board_id)->name);
 
-	strscpy(coredev->ir.phys, coredev->devpath, sizeof(coredev->ir.phys));
-	strlcat(coredev->ir.phys, "/ir0", sizeof(coredev->ir.phys));
+	scnprintf(coredev->ir.phys, sizeof(coredev->ir.phys),
+		  "%s/ir0", coredev->devpath);
 
 	dev->device_name = coredev->ir.name;
 	dev->input_phys = coredev->ir.phys;
-- 
2.43.0