diff --git a/Makefile.build b/Makefile.build
index a736cc709ae1bf2eba8f4af0079f10c6b39cce67..17d34f4f74406718bbc03bc925f52a177bc07ad8 100644
--- a/Makefile.build
+++ b/Makefile.build
@@ -63,7 +63,7 @@ userprog_SRC += userprog/syscall.c	# System call handler.
 userprog_SRC += userprog/gdt.c		# GDT initialization.
 userprog_SRC += userprog/tss.c		# TSS management.
 userprog_SRC += userprog/syscall_exec.c
-userprog_SRC += userprog/syscall_exit.c
+userprog_SRC += userprog/syscall_open.c
 userprog_SRC += userprog/syscall_halt.c
 userprog_SRC += userprog/syscall_wait.c
 userprog_SRC += userprog/syscall_create.c