diff --git a/ch2/os/build.rs b/ch2/os/build.rs
new file mode 100644
index 0000000..026b308
--- /dev/null
+++ b/ch2/os/build.rs
@@ -0,0 +1,69 @@
+use std::fs::{read_dir, File};
+use std::io::{Result, Write};
+
+fn main() {
+    println!("cargo:rerun-if-changed=../user/src/");
+    println!("cargo:rerun-if-changed={}", TARGET_PATH);
+    insert_app_data().unwrap();
+}
+
+static TARGET_PATH: &str = "../user/target/riscv64gc-unknown-none-elf/release/";
+
+fn insert_app_data() -> Result<()> {
+    let mut f = File::create("src/link_app.S").unwrap();
+    let mut apps: Vec<_> = read_dir("../user/src/bin")
+        .unwrap()
+        .into_iter()
+        .map(|dir_entry| {
+            let mut name_with_ext = dir_entry.unwrap().file_name().into_string().unwrap();
+            name_with_ext.drain(name_with_ext.find('.').unwrap()..name_with_ext.len());
+            name_with_ext
+        })
+        .collect();
+    apps.sort();
+
+
+    ///
+    ///     .align 3   表示接下来的数据或代码 使用2^3 8字节对齐
+    ///     .section .data  下面属于data段
+    ///     .global _num_app  定义一个全局符号 _num_app
+    /// _num_app:  _num_app的位置的数据
+    ///     .quad 5  用来当做matedata  8字节的整数 表示有5个元素
+    ///     .quad app_0_start  依次存储每个app的开始的位置
+    ///     .quad app_1_start
+    ///     .quad app_2_start
+    ///     .quad app_3_start
+    ///     .quad app_4_start
+    ///     .quad app_4_end
+    writeln!(
+        f,
+        r#"
+    .align 3
+    .section .data
+    .global _num_app
+_num_app:
+    .quad {}"#,
+        apps.len()
+    )?;
+
+    for i in 0..apps.len() {
+        writeln!(f, r#"    .quad app_{}_start"#, i)?;
+    }
+    writeln!(f, r#"    .quad app_{}_end"#, apps.len() - 1)?;
+
+    for (idx, app) in apps.iter().enumerate() {
+        println!("app_{}: {}", idx, app);
+        writeln!(
+            f,
+            r#"
+    .section .data
+    .global app_{0}_start
+    .global app_{0}_end
+app_{0}_start:
+    .incbin "{2}{1}.bin"
+app_{0}_end:"#,
+            idx, app, TARGET_PATH
+        )?;
+    }
+    Ok(())
+}