Add some Rust code

nix-rust/src/lib.rs

@@ -0,0 +1,48 @@
+extern crate libc;
+extern crate tar;
+
+use std::fs;
+use std::io;
+use std::os::unix::fs::OpenOptionsExt;
+use std::path::Path;
+use tar::Archive;
+
+#[no_mangle]
+pub extern "C" fn unpack_tarfile(data: &[u8], dest_dir: &str) -> bool {
+    // FIXME: handle errors.
+
+    let dest_dir = Path::new(dest_dir);
+
+    let mut tar = Archive::new(data);
+
+    for file in tar.entries().unwrap() {
+        let mut file = file.unwrap();
+
+        let dest_file = dest_dir.join(file.header().path().unwrap());
+
+        fs::create_dir_all(dest_file.parent().unwrap()).unwrap();
+
+        match file.header().entry_type() {
+            tar::EntryType::Directory => {
+                fs::create_dir(dest_file).unwrap();
+            }
+            tar::EntryType::Regular => {
+                let mode = if file.header().mode().unwrap() & libc::S_IXUSR == 0 {
+                    0o666
+                } else {
+                    0o777
+                };
+                let mut f = fs::OpenOptions::new()
+                    .create(true)
+                    .write(true)
+                    .mode(mode)
+                    .open(dest_file)
+                    .unwrap();
+                io::copy(&mut file, &mut f).unwrap();
+            }
+            t => panic!("Unsupported tar entry type '{:?}'.", t),
+        }
+    }
+
+    true
+}