[PATCH] media: radio: Replace strlcat() with seq_buf in TEA drivers

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

In preparation for removing the deprecated strlcat() API[1],
replace the strscpy() and strlcat() calls used to construct
V4L2 card names in the TEA5777 and TEA575x radio drivers.

seq_buf tracks the current write position and remaining capacity
across appends, avoiding repeated scans of the destination buffer.
This preserves the resulting strings, including truncation behavior.

Link: https://github.com/KSPP/linux/issues/370 [1]
Signed-off-by: Mariia Nikitash <nikitash.mariiaw@gmail.com>
---
 drivers/media/radio/radio-tea5777.c | 10 ++++++++--
 drivers/media/radio/tea575x.c       | 10 ++++++++--
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/media/radio/radio-tea5777.c b/drivers/media/radio/radio-tea5777.c
index fb9de7bbcd19..2b1c7f6ddd60 100644
--- a/drivers/media/radio/radio-tea5777.c
+++ b/drivers/media/radio/radio-tea5777.c
@@ -13,6 +13,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/sched.h>
+#include <linux/seq_buf.h>
 #include <linux/slab.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-dev.h>
@@ -255,10 +256,15 @@ static int vidioc_querycap(struct file *file, void  *priv,
 					struct v4l2_capability *v)
 {
 	struct radio_tea5777 *tea = video_drvdata(file);
+	struct seq_buf s;
 
 	strscpy(v->driver, tea->v4l2_dev->name, sizeof(v->driver));
-	strscpy(v->card, tea->card, sizeof(v->card));
-	strlcat(v->card, " TEA5777", sizeof(v->card));
+
+	seq_buf_init(&s, (char *)v->card, sizeof(v->card));
+	seq_buf_puts(&s, (const char *)tea->card);
+	seq_buf_puts(&s, " TEA5777");
+	seq_buf_terminate(&s);
+
 	strscpy(v->bus_info, tea->bus_info, sizeof(v->bus_info));
 	return 0;
 }
diff --git a/drivers/media/radio/tea575x.c b/drivers/media/radio/tea575x.c
index c37315226c42..e49228eb7c46 100644
--- a/drivers/media/radio/tea575x.c
+++ b/drivers/media/radio/tea575x.c
@@ -9,6 +9,7 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
+#include <linux/seq_buf.h>
 #include <linux/sched.h>
 #include <asm/io.h>
 #include <media/v4l2-device.h>
@@ -221,10 +222,15 @@ static int vidioc_querycap(struct file *file, void  *priv,
 					struct v4l2_capability *v)
 {
 	struct snd_tea575x *tea = video_drvdata(file);
+	struct seq_buf s;
 
 	strscpy(v->driver, tea->v4l2_dev->name, sizeof(v->driver));
-	strscpy(v->card, tea->card, sizeof(v->card));
-	strlcat(v->card, tea->tea5759 ? " TEA5759" : " TEA5757", sizeof(v->card));
+
+	seq_buf_init(&s, (char *)v->card, sizeof(v->card));
+	seq_buf_puts(&s, (const char *)tea->card);
+	seq_buf_puts(&s, tea->tea5759 ? " TEA5759" : " TEA5757");
+	seq_buf_terminate(&s);
+
 	strscpy(v->bus_info, tea->bus_info, sizeof(v->bus_info));
 	return 0;
 }
-- 
2.43.0