Fixed other issues

userprog/syscall.c

@@ -79,6 +79,9 @@ syscall_handler (struct intr_frame *f UNUSED)
   case SYSCALL_OPEN:
     syscall_open(f);
 	break;
+  case SYSCALL_FILESIZE:
+	syscall_filesize(f);
+	break;
   default:
     printf ("WARNING: Invalid Syscall (%d)\n", syscall_number);
     thread_exit ();

userprog/system_calls.h

@@ -49,6 +49,11 @@ void syscall_write(struct intr_frame *f);
  */
 void syscall_open(struct intr_frame *f);
 
+/*
+ * Returns the size, in bytes, of the file open as fd.
+ */
+void syscall_filesize(struct intr_frame *f);
+
 /*
  * Deletes the file called file. Returns true if successful, false otherwise.
  * A file may be removed regardless of whether it is open or closed, and