linux/SDL_sysjoystick.c: Fix bug #3193:

Protect against any axis that isn't reported by EVIOCGBIT but still sends EV_ABS events; patch from <maxxus@gmail.com>. Original issue and description: The Dualshock 3's motion sensors don't seem to be reported by the call to EVIOCGBIT but they still send EV_ABS events. Because they're not reported by EVIOCGBIT they're not assigned a proper axis ids and the default of 0 is used, which is the valid id for the left analog sticks left/right axis. The attached patch sets the default axis id to ABS_MAX and then checks the axis id before performing the update. This will protect against EV_ABS events for axes that aren't reported or handled correctly.
libsdl-org · Aug 7, 2018 · 1b548a8 · 1b548a8
1 parent f10b27c
commit 1b548a8
Showing 1 changed file with 8 additions and 3 deletions.
diff --git a/src/joystick/linux/SDL_sysjoystick.c b/src/joystick/linux/SDL_sysjoystick.c
@@ -826,6 +826,9 @@ int SDL_SYS_JoystickOpen(SDL_Joystick *joystick)
 		return(-1);
 	}
 	SDL_memset(joystick->hwdata, 0, sizeof(*joystick->hwdata));
+#if SDL_INPUT_LINUXEV
+	SDL_memset(joystick->hwdata->abs_map, ABS_MAX, sizeof(*joystick->hwdata->abs_map)*ABS_MAX);
+#endif
 	joystick->hwdata->fd = fd;
 
 	/* Set the joystick to non-blocking read mode */
@@ -1123,15 +1126,17 @@ static __inline__ void EV_HandleEvents(SDL_Joystick *joystick)
 							events[i].value);
 					break;
 				    default:
-					events[i].value = EV_AxisCorrect(joystick, code, events[i].value);
+					if (joystick->hwdata->abs_map[code] != ABS_MAX ) {
+					  events[i].value = EV_AxisCorrect(joystick, code, events[i].value);
 #ifndef NO_LOGICAL_JOYSTICKS
-					if (!LogicalJoystickAxis(joystick,
+					  if (!LogicalJoystickAxis(joystick,
 				           joystick->hwdata->abs_map[code],
 					   events[i].value))
 #endif
-					SDL_PrivateJoystickAxis(joystick,
+					  SDL_PrivateJoystickAxis(joystick,
 				           joystick->hwdata->abs_map[code],
 					   events[i].value);
+					}
 					break;
 				}
 				break;