shell: flush keyboard buffer around exec to avoid stale input

shell: flush keyboard buffer around exec to avoid stale input

Author: pradosh-arduino

source/includes/keyboard.h

@@ -74,6 +74,11 @@ uint8_t getc();
  */
 int getc_nonblock();
 
+/**
+ * @brief Clears pending keyboard input so stale keypresses are discarded.
+ */
+void keyboard_flush_buffer(void);
+
 /**
  * @brief Converts the scancode passed to it to ASCII characters.
  * 
@@ -82,4 +87,4 @@ int getc_nonblock();
  */
 int handle_char_from_scancode(uint8_t data);
 
-#endif
+#endif

source/kernel/C/shell/commands/exec.c

@@ -14,6 +14,7 @@
 #include <userland.h>
 #include <graphics.h>
 #include <tty.h>
+#include <keyboard.h>
 
 int cmd_exec(int argc, char** argv)
 {
@@ -39,11 +40,14 @@ int cmd_exec(int argc, char** argv)
     user_argv[user_argc] = NULL;
 
     tty_flush_input();
+    keyboard_flush_buffer();
 
     if (userland_exec(path, user_argc, user_argv, NULL) != 0) {
+        keyboard_flush_buffer();
         eprintf("exec: failed to load ELF");
         return -1;
     }
 
+    keyboard_flush_buffer();
     return 0;
 }

source/kernel/C/user-input/keyboard.c

@@ -119,6 +119,9 @@ int getc_nonblock() {
     return 0; // no key available
 }
 
+void keyboard_flush_buffer(void) {
+    rb_clear(&kb_rb);
+}
 
 static bool extended = false;
 int handle_char_from_scancode(uint8_t data)
@@ -221,4 +224,4 @@ int handle_char_from_scancode(uint8_t data)
         return 0;
 
     return c;
-}
+}