samples: Replace strlcpy() with strscpy()

strlcpy() reads the entire source buffer first. This read may exceed
the destination size limit. This is both inefficient and can lead
to linear read overflows if a source string is not NUL-terminated[1].
Additionally, it returns the size of the source string, not the
resulting size of the destination string. In an effort to remove strlcpy()
completely[2], replace strlcpy() here with strscpy().

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy [1]
Link: https://github.com/KSPP/linux/issues/89 [2]
Cc: Masami Hiramatsu <[e-mail]>
Cc: Valentin Schneider <[e-mail]>
Cc: "Steven Rostedt (Google)" <[e-mail]>
Cc: Chuck Lever <[e-mail]>
Cc: Geliang Tang <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Christophe JAILLET <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Acked-by: "Steven Rostedt (Google)" <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Kees Cook <[e-mail]>

samples/trace_events/trace-events-sample.h

···
 	),
 
 	TP_fast_assign(
-		strlcpy(__entry->foo, foo, 10);
+		strscpy(__entry->foo, foo, 10);
 		__entry->bar	= bar;
 		memcpy(__get_dynamic_array(list), lst,
 		       __length_of(lst) * sizeof(int));

samples/v4l/v4l2-pci-skeleton.c

···
 {
 	struct skeleton *skel = video_drvdata(file);
 
-	strlcpy(cap->driver, KBUILD_MODNAME, sizeof(cap->driver));
-	strlcpy(cap->card, "V4L2 PCI Skeleton", sizeof(cap->card));
+	strscpy(cap->driver, KBUILD_MODNAME, sizeof(cap->driver));
+	strscpy(cap->card, "V4L2 PCI Skeleton", sizeof(cap->card));
 	snprintf(cap->bus_info, sizeof(cap->bus_info), "PCI:%s",
 		 pci_name(skel->pdev));
 	return 0;
···
 	i->type = V4L2_INPUT_TYPE_CAMERA;
 	if (i->index == 0) {
 		i->std = SKEL_TVNORMS;
-		strlcpy(i->name, "S-Video", sizeof(i->name));
+		strscpy(i->name, "S-Video", sizeof(i->name));
 		i->capabilities = V4L2_IN_CAP_STD;
 	} else {
 		i->std = 0;
-		strlcpy(i->name, "HDMI", sizeof(i->name));
+		strscpy(i->name, "HDMI", sizeof(i->name));
 		i->capabilities = V4L2_IN_CAP_DV_TIMINGS;
 	}
 	return 0;
···
 
 	/* Initialize the video_device structure */
 	vdev = &skel->vdev;
-	strlcpy(vdev->name, KBUILD_MODNAME, sizeof(vdev->name));
+	strscpy(vdev->name, KBUILD_MODNAME, sizeof(vdev->name));
 	/*
 	 * There is nothing to clean up, so release is set to an empty release
 	 * function. The release callback must be non-NULL.