diff --git a/Cargo.lock b/Cargo.lock
index beb901a..17eceec 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -55,6 +55,14 @@ dependencies = [
  "vec_map",
 ]
 
+[[package]]
+name = "elf"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "byteorder",
+]
+
 [[package]]
 name = "heck"
 version = "0.3.3"
@@ -132,7 +140,7 @@ name = "rsld"
 version = "0.1.0"
 dependencies = [
  "anyhow",
- "byteorder",
+ "elf",
  "structopt",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index 8589242..d13077e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,7 +3,10 @@ name = "rsld"
 version = "0.1.0"
 edition = "2018"
 
+[workspace]
+members = ["elf"]
+
 [dependencies]
 anyhow = "1.0.41"
-byteorder = "1.4.3"
 structopt = "0.3.21"
+elf = { path = "elf" }
diff --git a/elf/Cargo.toml b/elf/Cargo.toml
new file mode 100644
index 0000000..68dee33
--- /dev/null
+++ b/elf/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "elf"
+version = "0.1.0"
+edition = "2018"
+
+[dependencies]
+anyhow = "1.0.41"
+byteorder = "1.4.3"
diff --git a/src/elf.rs b/elf/src/lib.rs
similarity index 85%
rename from src/elf.rs
rename to elf/src/lib.rs
index 6fc68a1..edc8f07 100644
--- a/src/elf.rs
+++ b/elf/src/lib.rs
@@ -4,6 +4,8 @@ use std::mem::MaybeUninit;
 use anyhow::Result;
 use byteorder::{LittleEndian, ReadBytesExt};
 
+const EI_DATA: i32 = 5;
+
 #[derive(Debug, Default)]
 pub struct Elf {
     header: Header,
@@ -43,5 +45,10 @@ impl Elf {
         Ok(elf)
     }
 
-    pub fn write<W: Write>(&self, mut w: W) {}
+    pub fn write<W: Write>(&self, mut w: W) -> Result<()> {
+        w.write(&self.header.e_ident)?;
+        w.flush()?;
+
+        Ok(())
+    }
 }
diff --git a/src/link.rs b/src/link.rs
index d6d03d8..892dbbf 100644
--- a/src/link.rs
+++ b/src/link.rs
@@ -2,11 +2,13 @@ use std::fs::{File, OpenOptions};
 use std::os::unix::fs::OpenOptionsExt;
 
 use anyhow::{Context, Result};
+use elf::Elf;
 
-use crate::elf::Elf;
 use crate::{LinkUnit, Opt};
 
 pub(crate) fn link(opt: &Opt) -> Result<()> {
+    let res = Elf::default();
+
     for unit in &opt.units {
         match unit {
             LinkUnit::Path(path) => {
@@ -17,7 +19,6 @@ pub(crate) fn link(opt: &Opt) -> Result<()> {
         }
     }
 
-    let res = Elf::default();
     if let Some(path) = &opt.out {
         let path = crate::utils::normalize_path(path);
         let file = OpenOptions::new()
diff --git a/src/main.rs b/src/main.rs
index 13a4009..bb3f507 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,3 @@
-mod elf;
 mod link;
 mod utils;