[PATCHv4] media: cec: extron-da-hd-4k-plus: Fix Wformat-truncation

Commit Message

Hans Verkuil April 1, 2025, 1:20 p.m. UTC

Fix gcc8 warning:

drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c:1014:44: warning: 'DCEC' directive output may be truncated writing 4 bytes into a region of size between 0 and 53 [-Wformat-truncation=]

Resizing the 'buf' and 'cmd' arrays fixed the warning.

Signed-off-by: Hans Verkuil <[e-mail]>
Reported-by: Ricardo Ribalda <[e-mail]>
Reviewed-by: Ricardo Ribalda <[e-mail]>
---
Change since v3:

Updated commit message.

Change since v2:

Redid the patch, fixing the buffer sizes. It turned out that was the problem.
It now passes build-ancient (I checked the logs this time).
Signed-off-by: Hans Verkuil <[e-mail]>
---
 .../cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c    | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Patch

diff --git a/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c b/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c
index cfbfc4c1b2e6..5ebd9d73fb15 100644
--- a/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c
+++ b/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c
@@ -1002,8 +1002,8 @@  static int extron_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
 				    u32 signal_free_time, struct cec_msg *msg)
 {
 	struct extron_port *port = cec_get_drvdata(adap);
-	char buf[CEC_MAX_MSG_SIZE * 3 + 1];
-	char cmd[CEC_MAX_MSG_SIZE * 3 + 13];
+	char buf[(CEC_MAX_MSG_SIZE - 1) * 3 + 1];
+	char cmd[(CEC_MAX_MSG_SIZE - 1) * 3 + 15];
 	unsigned int i;

 	if (port->disconnected)
@@ -1013,7 +1013,8 @@  static int extron_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
 		sprintf(buf + i * 3, "%%%02X", msg->msg[i + 1]);
 	snprintf(cmd, sizeof(cmd), "W%c%u*%u*%u*%sDCEC",
 		 port->direction, port->port.port,
-		 cec_msg_initiator(msg), cec_msg_destination(msg), buf);
+		 cec_msg_initiator(msg),
+		 cec_msg_destination(msg), buf);
 	return extron_send_and_wait(port->extron, port, cmd, NULL);
 }