plugin: always obfuscate keycodes

Same approach as chosen in libinput-record, this leaves the F1-F10 out
but otherwise prints every other "normal" key (including modifiers) as
KEY_A.

In the future we may need some more specific approach but for now this
will do. For the use-cases where we do need some specific approach,
libinput record and libinput debug-events will still show the full
keycode on request anyway.

Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1276>

src/evdev-frame.h

@@ -49,6 +49,10 @@ enum evdev_usage {
 
 	EVDEV_KEY_RESERVED = _evbit(EV_KEY, KEY_RESERVED),
 	EVDEV_KEY_ESC = _evbit(EV_KEY, KEY_ESC),
+	EVDEV_KEY_A = _evbit(EV_KEY, KEY_A),
+	EVDEV_KEY_CAPSLOCK = _evbit(EV_KEY, KEY_CAPSLOCK),
+	EVDEV_KEY_KP7 = _evbit(EV_KEY, KEY_KP7),
+	EVDEV_KEY_KPDOT = _evbit(EV_KEY, KEY_KPDOT),
 	EVDEV_KEY_MICMUTE = _evbit(EV_KEY, KEY_MICMUTE),
 	EVDEV_KEY_OK = _evbit(EV_KEY, KEY_OK),
 	EVDEV_KEY_LIGHTS_TOGGLE = _evbit(EV_KEY, KEY_LIGHTS_TOGGLE),

src/libinput-plugin.c

@@ -28,6 +28,7 @@
 #include "util-files.h"
 #include "util-list.h"
 
+#include "evdev-frame.h"
 #include "evdev-plugin.h"
 #include "libinput-plugin-button-debounce.h"
 #include "libinput-plugin-mouse-wheel-lowres.h"
@@ -508,9 +509,17 @@ print_frame(struct libinput *libinput, struct evdev_frame *frame, const char *pr
 	struct evdev_event *events = evdev_frame_get_events(frame, &nevents);
 
 	for (size_t i = 0; i < nevents; i++) {
-		struct evdev_event *e = &events[i];
+		struct evdev_event e = events[i];
+		enum evdev_usage usage = evdev_usage_enum(e.usage);
 
-		switch (evdev_usage_enum(e->usage)) {
+		if ((usage > EVDEV_KEY_ESC && usage < EVDEV_KEY_CAPSLOCK) ||
+		    (usage >= EVDEV_KEY_KP7 && usage <= EVDEV_KEY_KPDOT)) {
+			e.usage = evdev_usage_from(EVDEV_KEY_A);
+		} else if (usage == EVDEV_MSC_SCAN) {
+			e.value = 30; /* KEY_A scancode */
+		}
+
+		switch (evdev_usage_enum(e.usage)) {
 		case EVDEV_SYN_REPORT:
 			log_debug(
 				libinput,
@@ -528,9 +537,9 @@ print_frame(struct libinput *libinput, struct evdev_frame *frame, const char *pr
 				  prefix,
 				  time / 1000,
 				  time % 1000,
-				  evdev_event_get_type_name(e),
+				  evdev_event_get_type_name(&e),
-				  evdev_event_get_code_name(e),
+				  evdev_event_get_code_name(&e),
-				  e->value);
+				  e.value);
 			break;
 		default:
 			log_debug(libinput,
@@ -538,9 +547,9 @@ print_frame(struct libinput *libinput, struct evdev_frame *frame, const char *pr
 				  prefix,
 				  time / 1000,
 				  time % 1000,
-				  evdev_event_get_type_name(e),
+				  evdev_event_get_type_name(&e),
-				  evdev_event_get_code_name(e),
+				  evdev_event_get_code_name(&e),
-				  e->value);
+				  e.value);
 			break;
 		}
 	}

test/test-keyboard.c

@@ -523,6 +523,52 @@ START_TEST(keyboard_alt_printscreen)
 }
 END_TEST
 
+START_TEST(keyboard_keycode_obfuscation)
+{
+#ifdef EVENT_DEBUGGING
+	struct litest_device *dev = litest_current_device();
+	struct libinput *li = dev->libinput;
+
+	litest_drain_events(li);
+
+	litest_with_logcapture(li, capture)
+	{
+		litest_event(dev, EV_KEY, KEY_Q, 1);
+		litest_event(dev, EV_SYN, SYN_REPORT, 0);
+		litest_event(dev, EV_KEY, KEY_Q, 0);
+		litest_event(dev, EV_SYN, SYN_REPORT, 0);
+		litest_dispatch(li);
+		litest_drain_events(li);
+
+		/* clang-format off */
+		/* We get two possible debug messages:
+		 *  Queuing  event14  KEYBOARD_KEY                 +0.000s KEY_Q (16) released
+		 *  event14: plugin evdev           - 0.000 EV_KEY           KEY_Q                   0
+		 *
+		 * The latter must not exist, it must be obfuscated to KEY_A
+		 */
+		/* clang-format on */
+		char **strv = capture->debugs;
+		size_t index;
+		litest_assert(strv_find_substring(strv, "KEY_Q", &index));
+		do {
+			litest_assert_str_not_in("EV_KEY", strv[index]);
+			strv += index + 1;
+		} while (strv_find_substring(strv, "KEY_Q", &index));
+
+		strv = capture->debugs;
+		litest_assert(strv_find_substring(strv, "KEY_A", &index));
+		do {
+			litest_assert_str_in("EV_KEY", strv[index]);
+			strv += index + 1;
+		} while (strv_find_substring(strv, "KEY_A", &index));
+	}
+#else
+	return LITEST_SKIP;
+#endif
+}
+END_TEST
+
 TEST_COLLECTION(keyboard)
 {
 	/* clang-format off */
@@ -541,5 +587,6 @@ TEST_COLLECTION(keyboard)
 	litest_add(keyboard_no_scroll, LITEST_KEYS, LITEST_WHEEL);
 
 	litest_add_for_device(keyboard_alt_printscreen, LITEST_KEYBOARD);
+	litest_add_for_device(keyboard_keycode_obfuscation, LITEST_KEYBOARD);
 	/* clang-format on */
 }