start to implementig clone to create namespaces

src/namespace/create_ns.rs

@@ -0,0 +1,43 @@
+use std::fs::create_dir;
+use std::io::{Result, ErrorKind};
+use std::fs::File;
+use crate::namespace::consts::{
+    NET_NS_DIR,
+    PROC_NS_DIR
+};
+use nix::mount::{
+    mount,
+    MsFlags
+};
+
+pub fn create_ns() -> Result<()> {
+    create_ns_dir()?;
+    let nsdir = format!("{}/{}",NET_NS_DIR,"fake-net");
+    File::create(nsdir.clone())?;
+    bind_ns_file(nsdir)?;
+    Ok(())
+}
+
+fn create_ns_dir() -> Result<()> {
+    match create_dir(NET_NS_DIR) {
+        Err(e) if e.kind() != ErrorKind::AlreadyExists => {
+            Err(e)
+        },
+        _ => {
+            Ok(())
+        },
+    }
+}
+
+fn bind_ns_file(ns_file: String) -> Result<()> {
+    match create_mount(ns_file) {
+        Ok(_mount) => {
+            Ok(())
+        },
+        Err(e) => Err(e),
+    }
+}
+
+fn create_mount(ns_file: String) -> Result<()> {
+    Ok(mount::<str, str, str, str>(Some(PROC_NS_DIR), ns_file.as_str(), None, MsFlags::MS_BIND, None)?)
+}