util: add tar unpack helper

3 files changed, 39 insertions, 31 deletions

diff --git a/src/runner/runc/init.rs b/src/runner/runc/init.rs
index 658b318..e574789 100644
--- a/src/runner/runc/init.rs
+++ b/src/runner/runc/init.rs
@@ -1,9 +1,6 @@
 use std::{
-	ffi::CString,
 	fs::{DirBuilder, File},
 	io,
-	os::unix::ffi::OsStrExt,
-	path::Path,
 };
 
 use nix::{
@@ -12,7 +9,7 @@ use nix::{
 };
 use serde::{Deserialize, Serialize};
 
-use crate::util::ToIOResult;
+use crate::util::{self, ToIOResult};
 
 fn prepare_buildtmp() -> io::Result<()> {
 	mount::mount::<_, _, _, str>(
@@ -24,33 +21,7 @@ fn prepare_buildtmp() -> io::Result<()> {
 	)
 	.to_io_result()?;
 
-	DirBuilder::new().create("build/tmp/rootfs")?;
-
-	{
-		let file = File::open("build/rootfs.tar")?;
-		let mut archive = tar::Archive::new(file);
-		archive.set_preserve_permissions(true);
-		archive.set_preserve_mtime(true);
-		archive.set_unpack_xattrs(true);
-
-		let dst = Path::new("build/tmp/rootfs");
-
-		for entry_r in archive.entries()? {
-			let mut entry = entry_r?;
-			if entry.unpack_in(dst)? {
-				let header = entry.header();
-				let uid = header.uid()? as libc::uid_t;
-				let gid = header.gid()? as libc::gid_t;
-
-				let path = CString::new(dst.join(entry.path()?).as_os_str().as_bytes())
-					.map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
-				if unsafe { libc::lchown(path.as_ptr(), uid, gid) } < 0 {
-					return Err(io::Error::last_os_error());
-				}
-			}
-		}
-	}
-
+	util::tar::unpack(File::open("build/rootfs.tar")?, "build/tmp/rootfs")?;
 	DirBuilder::new().create("build/tmp/runc")?;
 
 	Ok(())
diff --git a/src/util.rs b/src/util.rs
index cbbfb6a..f5bbfaa 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -1,3 +1,5 @@
+pub mod tar;
+
 use std::{
 	io::{Error, ErrorKind, Result},
 	process::ExitStatus,
diff --git a/src/util/tar.rs b/src/util/tar.rs
new file mode 100644
index 0000000..07ad795
--- /dev/null
+++ b/src/util/tar.rs
@@ -0,0 +1,35 @@
+use std::{
+	ffi::CString,
+	fs::DirBuilder,
+	io::{self, Read},
+	os::unix::ffi::OsStrExt,
+	path::Path,
+};
+
+pub fn unpack<R: Read, P: AsRef<Path>>(archive: R, dest: P) -> io::Result<()> {
+	let dest_path = dest.as_ref();
+
+	DirBuilder::new().recursive(true).create(dest_path)?;
+
+	let mut ar = tar::Archive::new(archive);
+	ar.set_preserve_permissions(true);
+	ar.set_preserve_mtime(true);
+	ar.set_unpack_xattrs(true);
+
+	for entry_r in ar.entries()? {
+		let mut entry = entry_r?;
+		if entry.unpack_in(dest_path)? {
+			let header = entry.header();
+			let uid = header.uid()? as libc::uid_t;
+			let gid = header.gid()? as libc::gid_t;
+
+			let path = CString::new(dest_path.join(entry.path()?).as_os_str().as_bytes())
+				.map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
+			if unsafe { libc::lchown(path.as_ptr(), uid, gid) } < 0 {
+				return Err(io::Error::last_os_error());
+			}
+		}
+	}
+
+	Ok(())
+}