Update

src/devices/shutdown.h

+#ifndef DEVICES_SHUTDOWN_H
+#define DEVICES_SHUTDOWN_H
+
+#include <debug.h>
+
+/* How to shut down when Pintos has nothing left to do. */
+enum shutdown_type
+  {
+    SHUTDOWN_NONE,              /* Loop forever. */
+    SHUTDOWN_POWER_OFF,         /* Power off the machine (if possible). */
+    SHUTDOWN_REBOOT,            /* Reboot the machine (if possible). */
+  };
+
+void shutdown (void);
+void shutdown_configure (enum shutdown_type);
+void shutdown_reboot (void) NO_RETURN;
+void shutdown_power_off (void) NO_RETURN;
+
+#endif /* devices/shutdown.h */