fix(zaparoo): forward keyboard input to launcher frontend

While the launcher owns the screen the framebuffer path releases the evdev
grab, so its Qt frontend reads keyboards directly. Keyboard keys only went to
the core (user_io_kbd), so the frontend never saw them while controllers did.

Grab keyboards (only) while the launcher is active so the frontend can't read
them directly, and bridge their keys into the virtual uinput device the same
way controllers are bridged. MENU/F12 and keys while the OSD is open still go
to user_io_kbd so System Settings stays reachable from the keyboard.

The launcher input logic lives in support/zaparoo/alt_launcher.cpp; input.cpp
gets only minimal hook calls.

Author: wizzomafizzo

input.cpp

@@ -3897,6 +3897,14 @@ static void input_cb(struct input_event *ev, struct input_absinfo *absinfo, int
 				}
 
 				if (ev->code == KEY_HOMEPAGE) ev->code = KEY_MENU;
+
+				// Bridge keys to the launcher's uinput instead of the core (see alt_launcher.h).
+				if (alt_launcher_kbd_to_frontend(ev->code))
+				{
+					if (ev->value <= 1) uinp_send_key(ev->code, ev->value);
+					return;
+				}
+
 				if (send_key) user_io_kbd(ev->code, ev->value);
 				return;
 			}
@@ -5528,7 +5536,7 @@ int input_test(int getchar)
 						//Works only through cable or USB dongle.
 						if (input[n].vid == 0x045e && input[n].pid == 0x0b00) input[n].quirk = QUIRK_SHIFT;
 
-						ioctl(pool[n].fd, EVIOCGRAB, (grabbed | user_io_osd_is_visible()) ? 1 : 0);
+						ioctl(pool[n].fd, EVIOCGRAB, (grabbed | user_io_osd_is_visible() | alt_launcher_kbd_grab(pool[n].fd)) ? 1 : 0);
 
 						n++;
 						if (n >= NUMDEV) break;
@@ -6463,7 +6471,7 @@ void input_switch(int grab)
 
 	for (int i = 0; i < NUMDEV; i++)
 	{
-		if (pool[i].fd >= 0) ioctl(pool[i].fd, EVIOCGRAB, (grabbed | user_io_osd_is_visible()) ? 1 : 0);
+		if (pool[i].fd >= 0) ioctl(pool[i].fd, EVIOCGRAB, (grabbed | user_io_osd_is_visible() | alt_launcher_kbd_grab(pool[i].fd)) ? 1 : 0);
 	}
 }
 

support/zaparoo/alt_launcher.cpp

@@ -65,6 +65,28 @@ uint16_t alt_launcher_fb_terminal_key(uint32_t mask, bool osd_button)
 	return 0;
 }
 
+// Standard keyboards report letters + ESC; gamepads/mice report BTN_* instead.
+static bool fd_is_keyboard(int fd)
+{
+	if (fd < 0) return false;
+	unsigned char kb[(KEY_MAX + 7) / 8] = {};
+	if (ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(kb)), kb) < 0) return false;
+	#define BIT_SET(b) (kb[(b) / 8] & (1 << ((b) % 8)))
+	return BIT_SET(KEY_ESC) && BIT_SET(KEY_A) && BIT_SET(KEY_Z);
+	#undef BIT_SET
+}
+
+int alt_launcher_kbd_grab(int fd)
+{
+	return (alt_launcher_active() && fd_is_keyboard(fd)) ? 1 : 0;
+}
+
+bool alt_launcher_kbd_to_frontend(uint16_t code)
+{
+	return alt_launcher_active() && !user_io_osd_is_visible()
+		&& code < 256 && code != KEY_MENU && code != KEY_F12;
+}
+
 static pid_t s_pid = 0;
 static int s_crash_count = 0;
 static unsigned long s_respawn_timer = 0;

support/zaparoo/alt_launcher.h

@@ -26,6 +26,12 @@ void alt_launcher_set_v_offset(int8_t v);
 void alt_launcher_cfg_apply(void);
 uint16_t alt_launcher_fb_terminal_key(uint32_t mask, bool osd_button);
 
+// Input hooks for input.cpp. While the launcher owns the screen its Qt frontend
+// reads keyboards directly, so we grab them (kbd_grab) and bridge keys via uinput
+// (kbd_to_frontend) to avoid double input; MENU/F12 and OSD-open keys are excluded.
+int alt_launcher_kbd_grab(int fd);
+bool alt_launcher_kbd_to_frontend(uint16_t code);
+
 bool zaparoo_is_native_core(void);
 void zaparoo_alt_launcher_init_for_core(void);
 void zaparoo_alt_launcher_init_for_menu(void);