diff --git a/src/dracut-cpio/Cargo.lock b/src/dracut-cpio/Cargo.lock
new file mode 100644
index 0000000000..75dca6fba2
--- /dev/null
+++ b/src/dracut-cpio/Cargo.lock
@@ -0,0 +1,12 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "crosvm"
+version = "0.1.0"
+
+[[package]]
+name = "dracut-cpio"
+version = "0.1.0"
+dependencies = [
+ "crosvm",
+]
diff --git a/src/dracut-cpio/Cargo.toml b/src/dracut-cpio/Cargo.toml
new file mode 100644
index 0000000000..28cfb15853
--- /dev/null
+++ b/src/dracut-cpio/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "dracut-cpio"
+description = "cpio archive generator for Dracut"
+authors = ["David Disseldorp"]
+license = "GPL-2.0"
+version = "0.1.0"
+edition = "2018"
+
+[dependencies]
+crosvm = { path = "third_party/crosvm" }
+# please avoid adding any more dependencies
diff --git a/src/dracut-cpio/src/main.rs b/src/dracut-cpio/src/main.rs
new file mode 100644
index 0000000000..f1562e557f
--- /dev/null
+++ b/src/dracut-cpio/src/main.rs
@@ -0,0 +1,1717 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2021 SUSE LLC
+
+use std::convert::TryInto;
+use std::env;
+use std::ffi::OsStr;
+use std::fs;
+use std::io;
+use std::io::prelude::*;
+use std::os::unix::ffi::OsStrExt;
+use std::os::unix::fs::FileTypeExt;
+use std::os::unix::fs::MetadataExt as UnixMetadataExt;
+use std::path::{Path, PathBuf};
+
+use crosvm::argument::{self, Argument};
+
+macro_rules! NEWC_HDR_FMT {
+    () => {
+        concat!(
+            "{magic}{ino:08X}{mode:08X}{uid:08X}{gid:08X}{nlink:08X}",
+            "{mtime:08X}{filesize:08X}{major:08X}{minor:08X}{rmajor:08X}",
+            "{rminor:08X}{namesize:08X}{chksum:08X}"
+        )
+    };
+}
+
+// Don't print debug messages on release builds...
+#[cfg(debug_assertions)]
+macro_rules! dout {
+    ($($l:tt)*) => { println!($($l)*); }
+}
+#[cfg(not(debug_assertions))]
+macro_rules! dout {
+    ($($l:tt)*) => {};
+}
+
+const NEWC_HDR_LEN: u64 = 110;
+const PATH_MAX: u64 = 4096;
+
+struct HardlinkPath {
+    infile: PathBuf,
+    outfile: PathBuf,
+}
+
+struct HardlinkState {
+    names: Vec<HardlinkPath>,
+    source_ino: u64,
+    mapped_ino: u32,
+    nlink: u32,
+    seen: u32,
+}
+
+struct DevState {
+    dev: u64,
+    hls: Vec<HardlinkState>,
+}
+
+struct ArchiveProperties {
+    // first inode number to use. @ArchiveState.ino increments from this.
+    initial_ino: u32,
+    // if non-zero, then align file data segments to this offset by injecting
+    // extra zeros after the filename string terminator.
+    data_align: u32,
+    // When injecting extra zeros into the filename field for data alignment,
+    // ensure that it doesn't exceed this size. The linux kernel will ignore
+    // files where namesize is larger than PATH_MAX, hence the need for this.
+    namesize_max: u32,
+    // if the archive is being appended to the end of an existing file, then
+    // @initial_data_off is used when calculating @data_align alignment.
+    initial_data_off: u64,
+    // delimiter character for the stdin file list
+    list_separator: u8,
+    // mtime, uid and gid to use for archived inodes, instead of the value
+    // reported by stat.
+    fixed_mtime: Option<u32>,
+    fixed_uid: Option<u32>,
+    fixed_gid: Option<u32>,
+    // When archiving a subset of hardlinks, nlink values in the archive can
+    // represent the subset (renumber_nlink=true) or the original source file
+    // nlink values (renumber_nlink=false), where the latter matches GNU cpio.
+    renumber_nlink: bool,
+    // If OUTPUT file exists, then zero-truncate it instead of appending. The
+    // default append behaviour chains archives back-to-back, i.e. multiple
+    // archives will be separated by a TRAILER and 512-byte padding.
+    // See Linux's Documentation/driver-api/early-userspace/buffer-format.rst
+    // for details on how chained initramfs archives are handled.
+    truncate_existing: bool,
+}
+
+impl ArchiveProperties {
+    pub fn default() -> ArchiveProperties {
+        ArchiveProperties {
+            initial_ino: 0, // match GNU cpio numbering
+            data_align: 0,
+            namesize_max: PATH_MAX as u32,
+            initial_data_off: 0,
+            list_separator: b'\n',
+            fixed_mtime: None,
+            fixed_uid: None,
+            fixed_gid: None,
+            renumber_nlink: false,
+            truncate_existing: false,
+        }
+    }
+}
+
+struct ArchiveState {
+    // 2d dev + inode vector serves two purposes:
+    // - dev index provides reproducible major,minor values
+    // - inode@dev provides hardlink state tracking
+    ids: Vec<DevState>,
+    // offset from the start of this archive
+    off: u64,
+    // next mapped inode number, used instead of source file inode numbers to
+    // ensure reproducability. XXX: should track inode per mapped dev?
+    ino: u32,
+}
+
+impl ArchiveState {
+    pub fn new(ino_start: u32) -> ArchiveState {
+        ArchiveState {
+            ids: Vec::new(),
+            off: 0,
+            ino: ino_start,
+        }
+    }
+
+    // lookup or create DevState for @dev. Return @major/@minor based on index
+    pub fn dev_seen(&mut self, dev: u64) -> Option<(u32, u32)> {
+        let index: u64 = match self.ids.iter().position(|i| i.dev == dev) {
+            Some(idx) => idx.try_into().ok()?,
+            None => {
+                self.ids.push(DevState {
+                    dev: dev,
+                    hls: Vec::new(),
+                });
+                (self.ids.len() - 1).try_into().ok()?
+            }
+        };
+
+        let major: u32 = (index >> 32).try_into().unwrap();
+        let minor: u32 = (index & u64::from(u32::MAX)).try_into().unwrap();
+        Some((major, minor))
+    }
+
+    // Check whether we've already seen this hardlink's dev/inode combination.
+    // If already seen, fill the existing mapped_ino.
+    // Return true if this entry has been deferred (seen != nlinks)
+    pub fn hardlink_seen<W: Write + Seek>(
+        &mut self,
+        props: &ArchiveProperties,
+        mut writer: W,
+        major: u32,
+        minor: u32,
+        md: fs::Metadata,
+        inpath: &Path,
+        outpath: &Path,
+        mapped_ino: &mut Option<u32>,
+        mapped_nlink: &mut Option<u32>,
+    ) -> std::io::Result<bool> {
+        assert!(md.nlink() > 1);
+        let index = u64::from(major) << 32 | u64::from(minor);
+        // reverse index->major/minor conversion that was just done
+        let devstate: &mut DevState = &mut self.ids[index as usize];
+        let (_index, hl) = match devstate
+            .hls
+            .iter_mut()
+            .enumerate()
+            .find(|(_, hl)| hl.source_ino == md.ino())
+        {
+            Some(hl) => hl,
+            None => {
+                devstate.hls.push(HardlinkState {
+                    names: vec![HardlinkPath {
+                        infile: inpath.to_path_buf(),
+                        outfile: outpath.to_path_buf(),
+                    }],
+                    source_ino: md.ino(),
+                    mapped_ino: self.ino,
+                    nlink: md.nlink().try_into().unwrap(), // pre-checked
+                    seen: 1,
+                });
+                self.ino += 1; // ino is reserved for all subsequent links
+                return Ok(true);
+            }
+        };
+
+        if (*hl).names.iter().any(|n| n.infile == inpath) {
+            println!(
+                "duplicate hardlink path {} for {}",
+                inpath.display(),
+                md.ino()
+            );
+            // GNU cpio doesn't swallow duplicates
+        }
+
+        // hl.nlink may not match md.nlink if we've come here via
+        // archive_flush_unseen_hardlinks() .
+
+        (*hl).seen += 1;
+        if (*hl).seen > (*hl).nlink {
+            // GNU cpio powers through if a hardlink is listed multiple times,
+            // exceeding nlink.
+            println!("hardlink seen {} exceeds nlink {}", (*hl).seen, (*hl).nlink);
+        }
+
+        if (*hl).seen < (*hl).nlink {
+            (*hl).names.push(HardlinkPath {
+                infile: inpath.to_path_buf(),
+                outfile: outpath.to_path_buf(),
+            });
+            return Ok(true);
+        }
+
+        // a new HardlinkPath entry isn't added, as return path handles cpio
+        // outpath header *and* data segment.
+
+        for path in (*hl).names.iter().rev() {
+            dout!("writing hardlink {}", path.outfile.display());
+            // length already PATH_MAX validated
+            let fname = path.outfile.as_os_str().as_bytes();
+
+            write!(
+                writer,
+                NEWC_HDR_FMT!(),
+                magic = "070701",
+                ino = (*hl).mapped_ino,
+                mode = md.mode(),
+                uid = match props.fixed_uid {
+                    Some(u) => u,
+                    None => md.uid(),
+                },
+                gid = match props.fixed_gid {
+                    Some(g) => g,
+                    None => md.gid(),
+                },
+                nlink = match props.renumber_nlink {
+                    true => (*hl).nlink,
+                    false => md.nlink().try_into().unwrap(),
+                },
+                mtime = match props.fixed_mtime {
+                    Some(t) => t,
+                    None => md.mtime().try_into().unwrap(),
+                },
+                filesize = 0,
+                major = major,
+                minor = major,
+                rmajor = 0,
+                rminor = 0,
+                namesize = fname.len() + 1,
+                chksum = 0
+            )?;
+            self.off += NEWC_HDR_LEN;
+            writer.write_all(fname)?;
+            self.off += fname.len() as u64;
+            // +1 as padding starts after fname nulterm
+            let seeklen = 1 + archive_padlen(self.off + 1, 4);
+            writer.seek(io::SeekFrom::Current(seeklen as i64))?;
+            self.off += seeklen;
+        }
+        *mapped_ino = Some((*hl).mapped_ino);
+        // cpio nlink may be different to stat nlink if only a subset of links
+        // are archived.
+        if props.renumber_nlink {
+            *mapped_nlink = Some((*hl).nlink);
+        }
+
+        // GNU cpio: if a name is given multiple times, exceeding nlink, then
+        // subsequent names continue to be packed (with a repeat data segment),
+        // using the same mapped inode.
+        dout!("resetting hl at index {}", index);
+        hl.seen = 0;
+        hl.names.clear();
+
+        return Ok(false);
+    }
+}
+
+fn archive_path<W: Seek + Write>(
+    state: &mut ArchiveState,
+    props: &ArchiveProperties,
+    path: &Path,
+    mut writer: W,
+) -> std::io::Result<()> {
+    let inpath = path;
+    let mut outpath = path.clone();
+    let mut datalen: u32 = 0;
+    let mut rmajor: u32 = 0;
+    let mut rminor: u32 = 0;
+    let mut hardlink_ino: Option<u32> = None;
+    let mut hardlink_nlink: Option<u32> = None;
+    let mut symlink_tgt = PathBuf::new();
+    let mut data_align_seek: u32 = 0;
+
+    outpath = match outpath.strip_prefix("./") {
+        Ok(p) => {
+            if p.as_os_str().as_bytes().len() == 0 {
+                outpath // retain './' and '.' paths
+            } else {
+                p
+            }
+        }
+        Err(_) => outpath,
+    };
+    let fname = outpath.as_os_str().as_bytes();
+    if fname.len() + 1 >= PATH_MAX.try_into().unwrap() {
+        return Err(io::Error::new(io::ErrorKind::InvalidInput, "path too long"));
+    }
+
+    let md = match fs::symlink_metadata(inpath) {
+        Ok(m) => m,
+        Err(e) => {
+            println!("failed to get metadata for {}: {}", inpath.display(), e);
+            return Err(e);
+        }
+    };
+    dout!("archiving {} with mode {:o}", outpath.display(), md.mode());
+
+    let (major, minor) = match state.dev_seen(md.dev()) {
+        Some((maj, min)) => (maj, min),
+        None => return Err(io::Error::new(io::ErrorKind::Other, "failed to map dev")),
+    };
+
+    if md.nlink() > u32::MAX as u64 {
+        return Err(io::Error::new(
+            io::ErrorKind::InvalidInput,
+            "nlink too large",
+        ));
+    }
+
+    let mtime: u32 = match props.fixed_mtime {
+        Some(t) => t,
+        None => {
+            // check for 2106 epoch overflow
+            if md.mtime() > i64::from(u32::MAX) {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidInput,
+                    "mtime too large for cpio",
+                ));
+            }
+            md.mtime().try_into().unwrap()
+        }
+    };
+
+    let ftype = md.file_type();
+    if ftype.is_symlink() {
+        symlink_tgt = fs::read_link(inpath)?;
+        datalen = {
+            let d: usize = symlink_tgt.as_os_str().as_bytes().len();
+            if d >= PATH_MAX.try_into().unwrap() {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidInput,
+                    "symlink path too long",
+                ));
+            }
+            d.try_into().unwrap()
+        };
+        // no zero terminator for symlink target path
+    }
+
+    if ftype.is_block_device() || ftype.is_char_device() {
+        rmajor = (md.rdev() >> 8) as u32;
+        rminor = (md.rdev() & 0xff) as u32;
+    }
+
+    if ftype.is_file() {
+        datalen = {
+            if md.len() > u64::from(u32::MAX) {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidInput,
+                    "file too large for newc",
+                ));
+            }
+            md.len().try_into().unwrap()
+        };
+
+        if md.nlink() > 1 {
+            // follow GNU cpio's behaviour of attaching hardlink data only to
+            // the last entry in the archive.
+            let deferred = state.hardlink_seen(
+                &props,
+                &mut writer,
+                major,
+                minor,
+                md.clone(),
+                &inpath,
+                outpath,
+                &mut hardlink_ino,
+                &mut hardlink_nlink,
+            )?;
+            if deferred {
+                dout!("deferring hardlink {} data portion", outpath.display());
+                return Ok(());
+            }
+        }
+
+        if props.data_align > 0 && datalen > props.data_align {
+            // XXX we're "bending" the newc spec a bit here to inject zeros
+            // after fname to provide data segment alignment. These zeros are
+            // accounted for in the namesize, but some applications may only
+            // expect a single zero-terminator (and 4 byte alignment). GNU cpio
+            // and Linux initramfs handle this fine as long as PATH_MAX isn't
+            // exceeded.
+            data_align_seek = {
+                let len: u64 = archive_padlen(
+                    props.initial_data_off + state.off + NEWC_HDR_LEN + fname.len() as u64 + 1,
+                    u64::from(props.data_align),
+                );
+                let padded_namesize = len + fname.len() as u64 + 1;
+                if padded_namesize > u64::from(props.namesize_max) {
+                    dout!(
+                        "{} misaligned. Required padding {} exceeds namesize maximum {}.",
+                        outpath.display(),
+                        len,
+                        props.namesize_max
+                    );
+                    0
+                } else {
+                    len.try_into().unwrap()
+                }
+            };
+        }
+    }
+
+    write!(
+        writer,
+        NEWC_HDR_FMT!(),
+        magic = "070701",
+        ino = match hardlink_ino {
+            Some(i) => i,
+            None => {
+                let i = state.ino;
+                state.ino += 1;
+                i
+            }
+        },
+        mode = md.mode(),
+        uid = match props.fixed_uid {
+            Some(u) => u,
+            None => md.uid(),
+        },
+        gid = match props.fixed_gid {
+            Some(g) => g,
+            None => md.gid(),
+        },
+        nlink = match hardlink_nlink {
+            Some(n) => n,
+            None => md.nlink().try_into().unwrap(),
+        },
+        mtime = mtime,
+        filesize = datalen,
+        major = major,
+        minor = major,
+        rmajor = rmajor,
+        rminor = rminor,
+        namesize = fname.len() + 1 + data_align_seek as usize,
+        chksum = 0
+    )?;
+    state.off += NEWC_HDR_LEN;
+
+    writer.write_all(fname)?;
+    state.off += fname.len() as u64;
+
+    let mut seek_len: i64 = 1; // fname nulterm
+    if data_align_seek > 0 {
+        seek_len += data_align_seek as i64;
+        assert_eq!(archive_padlen(state.off + seek_len as u64, 4), 0);
+    } else {
+        let padding_len = archive_padlen(state.off + seek_len as u64, 4);
+        seek_len += padding_len as i64;
+    }
+    writer.seek(io::SeekFrom::Current(seek_len))?;
+    state.off += seek_len as u64;
+
+    // io::copy() can reflink: https://github.com/rust-lang/rust/pull/75272 \o/
+    if datalen > 0 {
+        if ftype.is_file() {
+            let mut reader = io::BufReader::new(fs::File::open(inpath)?);
+            let copied = io::copy(&mut reader, &mut writer)?;
+            if copied != u64::from(datalen) {
+                return Err(io::Error::new(
+                    io::ErrorKind::UnexpectedEof,
+                    "copy returned unexpected length",
+                ));
+            }
+        } else if ftype.is_symlink() {
+            writer.write_all(symlink_tgt.as_os_str().as_bytes())?;
+        }
+        state.off += u64::from(datalen);
+        let dpad_len: usize = archive_padlen(state.off, 4).try_into().unwrap();
+        write!(writer, "{pad:.padlen$}", padlen = dpad_len, pad = "\0\0\0")?;
+        state.off += dpad_len as u64;
+    }
+
+    Ok(())
+}
+
+fn archive_padlen(off: u64, alignment: u64) -> u64 {
+    (alignment - (off & (alignment - 1))) % alignment
+}
+
+// this fn is inefficient, but optimizing for hardlinks isn't high priority
+fn archive_flush_unseen_hardlinks<W: Write + Seek>(
+    state: &mut ArchiveState,
+    props: &ArchiveProperties,
+    mut writer: W,
+) -> std::io::Result<()> {
+    let mut deferred_inpaths: Vec<PathBuf> = Vec::new();
+    for id in state.ids.iter_mut() {
+        for hl in id.hls.iter_mut() {
+            if hl.seen == 0 || hl.seen == hl.nlink {
+                dout!("HardlinkState complete with seen {}", hl.seen);
+                continue;
+            }
+            dout!(
+                "pending HardlinkState with seen {} != nlinks {}",
+                hl.seen,
+                hl.nlink
+            );
+
+            while hl.names.len() > 0 {
+                let path = hl.names.pop().unwrap();
+                deferred_inpaths.push(path.infile);
+            }
+            // ensure that data segment gets added on archive_path recall
+            hl.nlink = hl.seen;
+            hl.seen = 0;
+            // existing allocated inode should be used
+        }
+    }
+
+    if deferred_inpaths.len() > 0 {
+        // rotate-right to match gnu ordering
+        deferred_inpaths.rotate_right(1);
+
+        // .reverse() to match gnu ordering
+        for p in deferred_inpaths.iter().rev() {
+            archive_path(state, props, p.as_path(), &mut writer)?;
+        }
+    }
+
+    Ok(())
+}
+
+fn archive_trailer<W: Write>(mut writer: W, cur_off: u64) -> std::io::Result<u64> {
+    let fname = "TRAILER!!!";
+    let fname_len = fname.len() + 1;
+
+    write!(
+        writer,
+        NEWC_HDR_FMT!(),
+        magic = "070701",
+        ino = 0,
+        mode = 0,
+        uid = 0,
+        gid = 0,
+        nlink = 1,
+        mtime = 0,
+        filesize = 0,
+        major = 0,
+        minor = 0,
+        rmajor = 0,
+        rminor = 0,
+        namesize = fname_len,
+        chksum = 0
+    )?;
+    let mut off: u64 = cur_off + NEWC_HDR_LEN;
+
+    let padding_len = archive_padlen(off + fname_len as u64, 4);
+    write!(
+        writer,
+        "{}\0{pad:.padlen$}",
+        fname,
+        padlen = padding_len as usize,
+        pad = "\0\0\0"
+    )?;
+    off += fname_len as u64 + padding_len as u64;
+
+    Ok(off)
+}
+
+fn archive_loop<R: BufRead, W: Seek + Write>(
+    mut reader: R,
+    mut writer: W,
+    props: &ArchiveProperties,
+) -> std::io::Result<u64> {
+    if props.data_align > 0 && (props.initial_data_off + u64::from(props.data_align)) % 4 != 0 {
+        // must satisfy both data_align and cpio 4-byte padding alignment
+        return Err(io::Error::new(
+            io::ErrorKind::InvalidInput,
+            "data alignment must be a multiple of 4",
+        ));
+    }
+
+    let mut state = ArchiveState::new(props.initial_ino);
+    loop {
+        let mut linebuf: Vec<u8> = Vec::new();
+        let mut r = reader.by_ref().take(PATH_MAX);
+        match r.read_until(props.list_separator, &mut linebuf) {
+            Ok(l) => {
+                if l == 0 {
+                    break; // EOF
+                }
+                if l >= PATH_MAX.try_into().unwrap() {
+                    return Err(io::Error::new(io::ErrorKind::InvalidInput, "path too long"));
+                }
+            }
+            Err(e) => {
+                println!("read_until() failed: {}", e);
+                return Err(e);
+            }
+        };
+
+        // trim separator. len > 0 already checked.
+        let last_byte = linebuf.last().unwrap();
+        if *last_byte == props.list_separator {
+            linebuf.pop().unwrap();
+            if linebuf.len() == 0 {
+                continue;
+            }
+        } else {
+            println!(
+                "\'{:0x}\' ending not separator \'{:0x}\' terminated",
+                last_byte, props.list_separator
+            );
+        }
+
+        let linestr = OsStr::from_bytes(linebuf.as_slice());
+        let path = Path::new(linestr);
+        archive_path(&mut state, props, path, &mut writer)?;
+    }
+    archive_flush_unseen_hardlinks(&mut state, props, &mut writer)?;
+    state.off = archive_trailer(&mut writer, state.off)?;
+
+    // GNU cpio pads the end of an archive out to blocklen with zeros
+    let block_padlen = archive_padlen(state.off, 512);
+    if block_padlen > 0 {
+        let z = vec![0u8; block_padlen.try_into().unwrap()];
+        writer.write_all(&z)?;
+        state.off += block_padlen;
+    }
+    writer.flush()?;
+
+    Ok(state.off)
+}
+
+fn params_usage(params: &[Argument]) {
+    argument::print_help("dracut-cpio", "OUTPUT", params);
+    println!("\nExample: find fs-tree/ | dracut-cpio archive.cpio\n");
+}
+
+fn params_process(props: &mut ArchiveProperties) -> argument::Result<PathBuf> {
+    let params = &[
+        Argument::positional("OUTPUT", "Write cpio archive to this file path."),
+        Argument::value(
+            "data-align",
+            "ALIGNMENT",
+            "Attempt to pad archive to achieve ALIGNMENT for file data.",
+        ),
+        Argument::short_flag(
+            '0',
+            "null",
+            "Expect null delimeters in stdin filename list instead of newline.",
+        ),
+        Argument::value(
+            "mtime",
+            "EPOCH",
+            "Use EPOCH for archived mtime instead of filesystem reported values.",
+        ),
+        Argument::value(
+            "owner",
+            "UID:GID",
+            "Use UID and GID instead of filesystem reported owner values.",
+        ),
+        Argument::flag(
+            "truncate-existing",
+            "Truncate and overwrite any existing OUTPUT file, instead of appending.",
+        ),
+        Argument::short_flag('h', "help", "Print help message."),
+    ];
+
+    let mut positional_args = 0;
+    let args = env::args().skip(1); // skip binary name
+    let match_res = argument::set_arguments(args, params, |name, value| {
+        match name {
+            "" => positional_args += 1,
+            "data-align" => {
+                let v: u32 = value
+                    .unwrap()
+                    .parse()
+                    .map_err(|_| argument::Error::InvalidValue {
+                        value: value.unwrap().to_owned(),
+                        expected: String::from("data-align must be an integer"),
+                    })?;
+                if v > props.namesize_max {
+                    println!(
+                        concat!(
+                            "Requested data-align {} larger than namesize maximum {}.",
+                            " This will likely result in misalignment."
+                        ),
+                        v, props.namesize_max
+                    );
+                }
+                props.data_align = v;
+            }
+            "null" => props.list_separator = b'\0',
+            "mtime" => {
+                let v: u32 = value
+                    .unwrap()
+                    .parse()
+                    .map_err(|_| argument::Error::InvalidValue {
+                        value: value.unwrap().to_owned(),
+                        expected: String::from("mtime must be an integer"),
+                    })?;
+                props.fixed_mtime = Some(v);
+            }
+            "owner" => {
+                let ugv_parsed: argument::Result<Vec<u32>> = value
+                    .unwrap()
+                    .split(':')
+                    .map(|id| {
+                        id.parse().map_err(|_| argument::Error::InvalidValue {
+                            value: id.to_owned(),
+                            expected: String::from("uid/gid must be an integer"),
+                        })
+                    })
+                    .collect();
+
+                let ugv_parsed = ugv_parsed?;
+                if ugv_parsed.len() != 2 {
+                    return Err(argument::Error::InvalidValue {
+                        value: value.unwrap().to_owned(),
+                        expected: String::from("owner must be UID:GID"),
+                    });
+                }
+                props.fixed_uid = Some(ugv_parsed[0]);
+                props.fixed_gid = Some(ugv_parsed[1]);
+            }
+            "truncate-existing" => props.truncate_existing = true,
+            "help" => return Err(argument::Error::PrintHelp),
+            _ => unreachable!(),
+        };
+        Ok(())
+    });
+
+    match match_res {
+        Ok(_) => {
+            if positional_args != 1 {
+                params_usage(params);
+                return Err(argument::Error::ExpectedArgument(
+                    "one OUTPUT parameter required".to_string(),
+                ));
+            }
+        }
+        Err(e) => {
+            params_usage(params);
+            return Err(e);
+        }
+    }
+
+    let last_arg = env::args_os().last().unwrap();
+    Ok(PathBuf::from(&last_arg))
+}
+
+fn main() -> std::io::Result<()> {
+    let mut props = ArchiveProperties::default();
+    let output_path = match params_process(&mut props) {
+        Ok(p) => p,
+        Err(argument::Error::PrintHelp) => return Ok(()),
+        Err(e) => return Err(io::Error::new(io::ErrorKind::InvalidInput, e.to_string())),
+    };
+
+    let mut f = fs::OpenOptions::new()
+        .read(false)
+        .write(true)
+        .create(true)
+        .truncate(props.truncate_existing)
+        .open(&output_path)?;
+    if !props.truncate_existing {
+        props.initial_data_off = f.seek(io::SeekFrom::End(0))?;
+    }
+    let mut writer = io::BufWriter::new(f);
+
+    let stdin = std::io::stdin();
+    let mut reader = io::BufReader::new(stdin);
+
+    let _wrote = archive_loop(&mut reader, &mut writer, &props)?;
+
+    if props.initial_data_off > 0 {
+        dout!(
+            "appended {} bytes to archive {} at offset {}",
+            _wrote,
+            output_path.display(),
+            props.initial_data_off
+        );
+    } else {
+        dout!(
+            "wrote {} bytes to archive {}",
+            _wrote,
+            output_path.display()
+        );
+    }
+
+    Ok(())
+}
+
+// tests change working directory, so need to be run with --test-threads=1
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::cmp;
+    use std::os::unix::fs as unixfs;
+    use std::path::PathBuf;
+    use std::process::{Command, Stdio};
+
+    struct TempWorkDir {
+        prev_dir: PathBuf,
+        parent_tmp_dir: PathBuf,
+        cleanup_files: Vec<PathBuf>,
+        cleanup_dirs: Vec<PathBuf>,
+        ignore_cleanup: bool, // useful for debugging
+    }
+
+    impl TempWorkDir {
+        // create a temporary directory under CWD and cd into it.
+        // The directory will be cleaned up when twd goes out of scope.
+        pub fn new() -> TempWorkDir {
+            let mut buf = [0u8; 16];
+            let mut s = String::from("cpio-selftest-");
+            fs::File::open("/dev/urandom")
+                .unwrap()
+                .read_exact(&mut buf)
+                .unwrap();
+            for i in &buf {
+                s.push_str(&format!("{:02x}", i).to_string());
+            }
+            let mut twd = TempWorkDir {
+                prev_dir: env::current_dir().unwrap(),
+                parent_tmp_dir: {
+                    let mut t = env::current_dir().unwrap().clone();
+                    t.push(s);
+                    println!("parent_tmp_dir: {}", t.display());
+                    t
+                },
+                cleanup_files: Vec::new(),
+                cleanup_dirs: Vec::new(),
+                ignore_cleanup: false,
+            };
+            fs::create_dir(&twd.parent_tmp_dir).unwrap();
+            twd.cleanup_dirs.push(twd.parent_tmp_dir.clone());
+            env::set_current_dir(&twd.parent_tmp_dir).unwrap();
+
+            twd
+        }
+
+        pub fn create_tmp_file(&mut self, name: &str, len_bytes: u64) {
+            let mut bytes = len_bytes;
+            let f = fs::File::create(name).unwrap();
+            self.cleanup_files.push(PathBuf::from(name));
+            let mut writer = io::BufWriter::new(f);
+            let mut buf = [0u8; 512];
+
+            for (i, elem) in buf.iter_mut().enumerate() {
+                *elem = !(i & 0xFF) as u8;
+            }
+
+            while bytes > 0 {
+                let this_len = cmp::min(buf.len(), bytes.try_into().unwrap());
+                writer.write_all(&buf[0..this_len]).unwrap();
+                bytes -= this_len as u64;
+            }
+
+            writer.flush().unwrap();
+        }
+
+        pub fn create_tmp_dir(&mut self, name: &str) {
+            fs::create_dir(name).unwrap();
+            self.cleanup_dirs.push(PathBuf::from(name));
+        }
+    }
+
+    impl Drop for TempWorkDir {
+        fn drop(&mut self) {
+            for f in self.cleanup_files.iter().rev() {
+                if self.ignore_cleanup {
+                    println!("ignoring cleanup of file {}", f.display());
+                    continue;
+                }
+                println!("cleaning up test file at {}", f.display());
+                match fs::remove_file(f) {
+                    Err(e) => println!("file removal failed {}", e),
+                    Ok(_) => {}
+                };
+            }
+            for f in self.cleanup_dirs.iter().rev() {
+                if self.ignore_cleanup {
+                    println!("ignoring cleanup of dir {}", f.display());
+                    continue;
+                }
+                println!("cleaning up test dir at {}", f.display());
+                match fs::remove_dir(f) {
+                    Err(e) => println!("dir removal failed {}", e),
+                    Ok(_) => {}
+                };
+            }
+            println!("returning cwd to {}", self.prev_dir.display());
+            env::set_current_dir(self.prev_dir.as_path()).unwrap();
+        }
+    }
+
+    fn gnu_cpio_create(stdinput: &[u8], out: &str) {
+        let mut proc = Command::new("cpio")
+            .args(&["--quiet", "-o", "-H", "newc", "--reproducible", "-F", out])
+            .stdin(Stdio::piped())
+            .spawn()
+            .expect("GNU cpio failed to start");
+        {
+            let mut stdin = proc.stdin.take().unwrap();
+            stdin.write_all(stdinput).expect("Failed to write to stdin");
+        }
+
+        let status = proc.wait().unwrap();
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_empty_file() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file.txt", 0);
+
+        gnu_cpio_create("file.txt\n".as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        // use dracut-cpio to archive file.txt
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new("file.txt\n".as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert_eq!(wrote, 512);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_small_file() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file.txt", 33);
+
+        gnu_cpio_create("file.txt\n".as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new("file.txt\n".as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 2 + 33);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_prefixed_path() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file.txt", 0);
+
+        gnu_cpio_create("./file.txt\n".as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new("./file.txt\n".as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert_eq!(wrote, 512);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_absolute_path() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file.txt", 0);
+
+        let canon_path = fs::canonicalize("file.txt").unwrap();
+        let mut canon_file_list = canon_path.into_os_string();
+        canon_file_list.push("\n");
+
+        gnu_cpio_create(canon_file_list.as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(canon_file_list.as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert_eq!(wrote, 512);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_dir() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_dir("dir");
+
+        gnu_cpio_create("dir\n".as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new("dir\n".as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert_eq!(wrote, 512);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_dir_file() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_dir("dir");
+        twd.create_tmp_file("dir/file.txt", 512 * 32);
+        let file_list: &str = "dir\n\ndir/file.txt\n"; // double separator
+
+        gnu_cpio_create(file_list.as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list.as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 3 + 512 * 32);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_dot_path() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_dir("dir");
+        twd.create_tmp_file("dir/file.txt", 512 * 32);
+        let file_list: &str = ".\ndir\ndir/file.txt\n";
+
+        gnu_cpio_create(file_list.as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list.as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 4 + 512 * 32);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_dot_slash_path() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_dir("dir");
+        twd.create_tmp_file("dir/file.txt", 512 * 32);
+        let file_list: &str = "./\ndir\ndir/file.txt\n";
+
+        gnu_cpio_create(file_list.as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list.as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 4 + 512 * 32);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_symlink() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file.txt", 0);
+        unixfs::symlink("file.txt", "symlink.txt").unwrap();
+        twd.cleanup_files.push(PathBuf::from("symlink.txt"));
+
+        gnu_cpio_create("file.txt\nsymlink.txt\n".as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new("file.txt\nsymlink.txt\n".as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert_eq!(wrote, 512);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_fifo() {
+        let mut twd = TempWorkDir::new();
+
+        // mknod [OPTION]... NAME TYPE [MAJOR MINOR]
+        let mut proc = Command::new("mknod")
+            .args(&["fifo", "p"])
+            .spawn()
+            .expect("mknod failed to start");
+        assert!(proc.wait().unwrap().success());
+        twd.cleanup_files.push(PathBuf::from("fifo"));
+
+        gnu_cpio_create("fifo\n".as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new("fifo\n".as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert_eq!(wrote, 512);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_char() {
+        let mut twd = TempWorkDir::new();
+
+        gnu_cpio_create("/dev/zero\n".as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new("/dev/zero\n".as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert_eq!(wrote, 512);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_data_align() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_dir("dir");
+        twd.create_tmp_file("dir/file.txt", 1024 * 1024); // 1M
+
+        twd.create_tmp_dir("extractor");
+        let f = fs::File::create("extractor/dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new("dir\ndir/file.txt\n".as_bytes());
+        // 4k cpio data segment alignment injects zeros after filename nullterm
+        let wrote = archive_loop(
+            &mut reader,
+            &mut writer,
+            &ArchiveProperties {
+                data_align: 4096,
+                ..ArchiveProperties::default()
+            },
+        )
+        .unwrap();
+        twd.cleanup_files
+            .push(PathBuf::from("extractor/dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 3 + 1024 * 1024);
+
+        // check 4k data segment alignment
+        let mut proc = Command::new("diff")
+            .args(&["dir/file.txt", "-"])
+            .stdin(Stdio::piped())
+            .spawn()
+            .expect("diff failed to start");
+        {
+            let f = fs::File::open("extractor/dracut.cpio").unwrap();
+            let mut reader = io::BufReader::new(f);
+            reader.seek(io::SeekFrom::Start(4096)).unwrap();
+            let mut take = reader.take(1024 * 1024 as u64);
+            let mut stdin = proc.stdin.take().unwrap();
+            let copied = io::copy(&mut take, &mut stdin).unwrap();
+            assert_eq!(copied, 1024 * 1024);
+        }
+        let status = proc.wait().unwrap();
+        assert!(status.success());
+
+        // confirm that GNU cpio can extract fname-zeroed paths
+        let status = Command::new("cpio")
+            .current_dir("extractor")
+            .args(&["--quiet", "-i", "-H", "newc", "-F", "dracut.cpio"])
+            .status()
+            .expect("GNU cpio failed to start");
+        assert!(status.success());
+        twd.cleanup_files
+            .push(PathBuf::from("extractor/dir/file.txt"));
+        twd.cleanup_dirs.push(PathBuf::from("extractor/dir"));
+
+        let status = Command::new("diff")
+            .args(&["dir/file.txt", "extractor/dir/file.txt"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_data_align_off() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_dir("dir1");
+        twd.create_tmp_dir("dir2");
+        twd.create_tmp_dir("dir3");
+        twd.create_tmp_file("dir1/file.txt", 514 * 1024);
+
+        twd.create_tmp_dir("extractor");
+        let data_before_cpio = [5u8; 16384 + 4];
+        let f = fs::File::create("extractor/dracut.cpio").unwrap();
+        twd.cleanup_files
+            .push(PathBuf::from("extractor/dracut.cpio"));
+        let mut writer = io::BufWriter::new(f);
+        writer.write_all(&data_before_cpio).unwrap();
+        let mut reader = io::BufReader::new("dir1\ndir2\ndir3\ndir1/file.txt\n".as_bytes());
+        let wrote = archive_loop(
+            &mut reader,
+            &mut writer,
+            &ArchiveProperties {
+                data_align: 4096,
+                initial_data_off: data_before_cpio.len() as u64,
+                ..ArchiveProperties::default()
+            },
+        )
+        .unwrap();
+        assert!(wrote > NEWC_HDR_LEN * 5 + 514 * 1024);
+
+        let mut proc = Command::new("diff")
+            .args(&["dir1/file.txt", "-"])
+            .stdin(Stdio::piped())
+            .spawn()
+            .expect("diff failed to start");
+        {
+            let f = fs::File::open("extractor/dracut.cpio").unwrap();
+            let mut reader = io::BufReader::new(f);
+            reader.seek(io::SeekFrom::Start(16384 + 4096)).unwrap();
+            let mut take = reader.take(514 * 1024 as u64);
+            let mut stdin = proc.stdin.take().unwrap();
+            let copied = io::copy(&mut take, &mut stdin).unwrap();
+            assert_eq!(copied, 514 * 1024);
+        }
+        let status = proc.wait().unwrap();
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_data_align_off_bad() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file.txt", 514 * 1024);
+
+        let data_before_cpio = [5u8; 16384 + 3];
+        let f = fs::File::create("dracut.cpio").unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        let mut writer = io::BufWriter::new(f);
+        writer.write_all(&data_before_cpio).unwrap();
+        let mut reader = io::BufReader::new("file.txt\n".as_bytes());
+        let res = archive_loop(
+            &mut reader,
+            &mut writer,
+            &ArchiveProperties {
+                data_align: 4096,
+                initial_data_off: data_before_cpio.len() as u64,
+                ..ArchiveProperties::default()
+            },
+        );
+        assert!(res.is_err());
+        assert_eq!(io::ErrorKind::InvalidInput, res.unwrap_err().kind());
+    }
+
+    #[test]
+    fn test_archive_hardlinks_order() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file.txt", 512 * 4);
+        fs::hard_link("file.txt", "link1.txt").unwrap();
+        twd.cleanup_files.push(PathBuf::from("link1.txt"));
+        fs::hard_link("file.txt", "link2.txt").unwrap();
+        twd.cleanup_files.push(PathBuf::from("link2.txt"));
+        twd.create_tmp_file("another.txt", 512 * 4);
+        let file_list: &str = "file.txt\nanother.txt\nlink1.txt\nlink2.txt\n";
+
+        gnu_cpio_create(file_list.as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list.as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 5 + 512 * 8);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_hardlinks_empty() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file.txt", 0);
+        fs::hard_link("file.txt", "link1.txt").unwrap();
+        twd.cleanup_files.push(PathBuf::from("link1.txt"));
+        fs::hard_link("file.txt", "link2.txt").unwrap();
+        twd.cleanup_files.push(PathBuf::from("link2.txt"));
+        twd.create_tmp_file("another.txt", 512 * 4);
+        let file_list: &str = "file.txt\nanother.txt\nlink1.txt\nlink2.txt\n";
+
+        gnu_cpio_create(file_list.as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list.as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 5 + 512 * 4);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_hardlinks_missing() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file.txt", 512 * 4);
+        fs::hard_link("file.txt", "link1.txt").unwrap();
+        twd.cleanup_files.push(PathBuf::from("link1.txt"));
+        fs::hard_link("file.txt", "link2.txt").unwrap();
+        twd.cleanup_files.push(PathBuf::from("link2.txt"));
+        fs::hard_link("file.txt", "link3.txt").unwrap();
+        twd.cleanup_files.push(PathBuf::from("link3.txt"));
+        twd.create_tmp_file("another.txt", 512 * 4);
+        // link2 missing from the archive, throwing off deferrals
+        let file_list: &str = "file.txt\nanother.txt\nlink1.txt\nlink3.txt\n";
+
+        gnu_cpio_create(file_list.as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list.as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 5 + 512 * 8);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_hardlinks_multi() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file.txt", 512 * 4);
+        fs::hard_link("file.txt", "link1.txt").unwrap();
+        twd.cleanup_files.push(PathBuf::from("link1.txt"));
+        fs::hard_link("file.txt", "link2.txt").unwrap();
+        twd.cleanup_files.push(PathBuf::from("link2.txt"));
+        twd.create_tmp_file("another.txt", 512 * 4);
+        fs::hard_link("another.txt", "anotherlink.txt").unwrap();
+        twd.cleanup_files.push(PathBuf::from("anotherlink.txt"));
+        // link2 missing from the archive, throwing off deferrals
+        let file_list: &str = "file.txt\nanother.txt\nlink1.txt\nanotherlink.txt\n";
+
+        gnu_cpio_create(file_list.as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list.as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 5 + 512 * 8);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_duplicates() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file.txt", 512 * 4);
+        twd.create_tmp_file("another.txt", 512 * 4);
+        // file.txt is listed twice
+        let file_list: &str = "file.txt\nanother.txt\nfile.txt\n";
+
+        gnu_cpio_create(file_list.as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list.as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 4 + 512 * 12);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_hardlink_duplicates() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file.txt", 512 * 4);
+        fs::hard_link("file.txt", "ln1.txt").unwrap();
+        twd.cleanup_files.push(PathBuf::from("ln1.txt"));
+        fs::hard_link("file.txt", "ln2.txt").unwrap();
+        twd.cleanup_files.push(PathBuf::from("ln2.txt"));
+        twd.create_tmp_file("f2.txt", 512 * 4);
+        // ln1 listed twice
+        let file_list: &str = "file.txt\nf2.txt\nln1.txt\nln1.txt\nln1.txt\n";
+
+        gnu_cpio_create(file_list.as_bytes(), "gnu.cpio");
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list.as_bytes());
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 4 + 512 * 8);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_list_separator() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file1", 33);
+        twd.create_tmp_file("file2", 55);
+        let file_list_nulldelim: &str = "file1\0file2\0";
+
+        let mut proc = Command::new("cpio")
+            .args(&[
+                "--quiet",
+                "-o",
+                "-H",
+                "newc",
+                "--reproducible",
+                "-F",
+                "gnu.cpio",
+                "--null",
+            ])
+            .stdin(Stdio::piped())
+            .spawn()
+            .expect("GNU cpio failed to start");
+        {
+            let mut stdin = proc.stdin.take().unwrap();
+            stdin
+                .write_all(file_list_nulldelim.as_bytes())
+                .expect("Failed to write to stdin");
+        }
+
+        let status = proc.wait().unwrap();
+        assert!(status.success());
+        twd.cleanup_files.push(PathBuf::from("gnu.cpio"));
+
+        let f = fs::File::create("dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list_nulldelim.as_bytes());
+        let wrote = archive_loop(
+            &mut reader,
+            &mut writer,
+            &ArchiveProperties {
+                list_separator: b'\0',
+                ..ArchiveProperties::default()
+            },
+        )
+        .unwrap();
+        twd.cleanup_files.push(PathBuf::from("dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 3 + 33 + 55);
+
+        let status = Command::new("diff")
+            .args(&["gnu.cpio", "dracut.cpio"])
+            .status()
+            .expect("diff failed to start");
+        assert!(status.success());
+    }
+
+    #[test]
+    fn test_archive_fixed_mtime() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file1", 33);
+        twd.create_tmp_file("file2", 55);
+        let file_list: &str = "file1\nfile2\n";
+
+        twd.create_tmp_dir("extractor");
+        let f = fs::File::create("extractor/dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list.as_bytes());
+        let wrote = archive_loop(
+            &mut reader,
+            &mut writer,
+            &ArchiveProperties {
+                fixed_mtime: Some(0),
+                ..ArchiveProperties::default()
+            },
+        )
+        .unwrap();
+        twd.cleanup_files
+            .push(PathBuf::from("extractor/dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 3 + 33 + 55);
+
+        let status = Command::new("cpio")
+            .current_dir("extractor")
+            .args(&[
+                "--quiet",
+                "-i",
+                "--preserve-modification-time",
+                "-H",
+                "newc",
+                "-F",
+                "dracut.cpio",
+            ])
+            .status()
+            .expect("GNU cpio failed to start");
+        assert!(status.success());
+        twd.cleanup_files.push(PathBuf::from("extractor/file1"));
+        twd.cleanup_files.push(PathBuf::from("extractor/file2"));
+
+        let md = fs::symlink_metadata("extractor/file1").unwrap();
+        assert_eq!(md.mtime(), 0);
+        let md = fs::symlink_metadata("extractor/file2").unwrap();
+        assert_eq!(md.mtime(), 0);
+    }
+
+    #[test]
+    fn test_archive_stat_mtime() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file1", 33);
+        twd.create_tmp_file("file2", 55);
+        let file_list: &str = "file1\nfile2\n";
+
+        twd.create_tmp_dir("extractor");
+        let f = fs::File::create("extractor/dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list.as_bytes());
+        assert_eq!(ArchiveProperties::default().fixed_mtime, None);
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files
+            .push(PathBuf::from("extractor/dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 3 + 33 + 55);
+
+        let status = Command::new("cpio")
+            .current_dir("extractor")
+            .args(&[
+                "--quiet",
+                "-i",
+                "--preserve-modification-time",
+                "-H",
+                "newc",
+                "-F",
+                "dracut.cpio",
+            ])
+            .status()
+            .expect("GNU cpio failed to start");
+        assert!(status.success());
+        twd.cleanup_files.push(PathBuf::from("extractor/file1"));
+        twd.cleanup_files.push(PathBuf::from("extractor/file2"));
+
+        let src_md = fs::symlink_metadata("file1").unwrap();
+        let ex_md = fs::symlink_metadata("extractor/file1").unwrap();
+        assert_eq!(src_md.mtime(), ex_md.mtime());
+        let src_md = fs::symlink_metadata("file2").unwrap();
+        let ex_md = fs::symlink_metadata("extractor/file2").unwrap();
+        assert_eq!(src_md.mtime(), ex_md.mtime());
+    }
+
+    #[test]
+    fn test_archive_fixed_owner() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file1", 33);
+        twd.create_tmp_file("file2", 55);
+        let file_list: &str = "file1\nfile2\n";
+
+        let md = fs::symlink_metadata("file1").unwrap();
+        // ideally we should check the process euid, but this will do...
+        if md.uid() != 0 {
+            println!("SKIPPED: this test requires root");
+            return;
+        }
+
+        twd.create_tmp_dir("extractor");
+        let f = fs::File::create("extractor/dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list.as_bytes());
+        let wrote = archive_loop(
+            &mut reader,
+            &mut writer,
+            &ArchiveProperties {
+                fixed_uid: Some(65534),
+                fixed_gid: Some(65534),
+                ..ArchiveProperties::default()
+            },
+        )
+        .unwrap();
+        twd.cleanup_files
+            .push(PathBuf::from("extractor/dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 3 + 33 + 55);
+
+        let status = Command::new("cpio")
+            .current_dir("extractor")
+            .args(&["--quiet", "-i", "-H", "newc", "-F", "dracut.cpio"])
+            .status()
+            .expect("GNU cpio failed to start");
+        assert!(status.success());
+        twd.cleanup_files.push(PathBuf::from("extractor/file1"));
+        twd.cleanup_files.push(PathBuf::from("extractor/file2"));
+
+        let md = fs::symlink_metadata("extractor/file1").unwrap();
+        assert_eq!(md.uid(), 65534);
+        assert_eq!(md.gid(), 65534);
+        let md = fs::symlink_metadata("extractor/file2").unwrap();
+        assert_eq!(md.uid(), 65534);
+        assert_eq!(md.gid(), 65534);
+    }
+
+    #[test]
+    fn test_archive_stat_owner() {
+        let mut twd = TempWorkDir::new();
+        twd.create_tmp_file("file1", 33);
+        twd.create_tmp_file("file2", 55);
+        let file_list: &str = "file1\nfile2\n";
+
+        twd.create_tmp_dir("extractor");
+        let f = fs::File::create("extractor/dracut.cpio").unwrap();
+        let mut writer = io::BufWriter::new(f);
+        let mut reader = io::BufReader::new(file_list.as_bytes());
+        assert_eq!(ArchiveProperties::default().fixed_uid, None);
+        assert_eq!(ArchiveProperties::default().fixed_gid, None);
+        let wrote = archive_loop(&mut reader, &mut writer, &ArchiveProperties::default()).unwrap();
+        twd.cleanup_files
+            .push(PathBuf::from("extractor/dracut.cpio"));
+        assert!(wrote > NEWC_HDR_LEN * 3 + 33 + 55);
+
+        let status = Command::new("cpio")
+            .current_dir("extractor")
+            .args(&["--quiet", "-i", "-H", "newc", "-F", "dracut.cpio"])
+            .status()
+            .expect("GNU cpio failed to start");
+        assert!(status.success());
+        twd.cleanup_files.push(PathBuf::from("extractor/file1"));
+        twd.cleanup_files.push(PathBuf::from("extractor/file2"));
+
+        let src_md = fs::symlink_metadata("file1").unwrap();
+        let ex_md = fs::symlink_metadata("extractor/file1").unwrap();
+        assert_eq!(src_md.uid(), ex_md.uid());
+        assert_eq!(src_md.gid(), ex_md.gid());
+        let src_md = fs::symlink_metadata("file2").unwrap();
+        let ex_md = fs::symlink_metadata("extractor/file2").unwrap();
+        assert_eq!(src_md.uid(), ex_md.uid());
+        assert_eq!(src_md.gid(), ex_md.gid());
+    }
+}