Pipe OK.

user/src/lib.rs

@@ -9,6 +9,8 @@ pub mod console;
 mod syscall;
 mod lang_items;
 
+extern crate alloc;
+
 use syscall::*;
 use buddy_system_allocator::LockedHeap;
 
@@ -40,6 +42,8 @@ fn main() -> i32 {
     panic!("Cannot find main!");
 }
 
+pub fn close(fd: usize) -> isize { sys_close(fd) }
+pub fn pipe(pipe_fd: &mut [usize]) -> isize { sys_pipe(pipe_fd) }
 pub fn read(fd: usize, buf: &mut [u8]) -> isize { sys_read(fd, buf) }
 pub fn write(fd: usize, buf: &[u8]) -> isize { sys_write(fd, buf) }
 pub fn exit(exit_code: i32) -> ! { sys_exit(exit_code); }