diff --git a/Makefile.build b/Makefile.build
index 0810c23211f18d2e5061f89b0ae00b483078f7bd..9e4b7b916d0bcbce38a5e5989a9876ab84c44e4c 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