global: improve user storage security

global.c

@@ -13,9 +13,9 @@
  *
  */
 /** global definitions and methods (code)
- *  @file global.c
+ *  @file
  *  @author King Kévin <kingkevin@cuvoodoo.info>
- *  @date 2016-2019
+ *  @date 2016-2020
  */
 /* standard libraries */
 #include <stdint.h> // standard integer types
@@ -160,7 +160,7 @@ void sys_tick_handler(void)
 
 char user_input_get(void)
 {
-	while (!user_input_available) { // wait for user input
+	while (0 == user_input_used) { // wait for user input to be available (don't trust user_input_available since it user modifiable)
 		__WFI(); // go to sleep
 	}
 	volatile char to_return = user_input_buffer[user_input_i]; // get the next available character

global.h

@@ -13,9 +13,9 @@
  *
  */
 /** global definitions and methods (API)
- *  @file global.h
+ *  @file
  *  @author King Kévin <kingkevin@cuvoodoo.info>
- *  @date 2016-2019
+ *  @date 2016-2020
  */
 #pragma once