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Revert "Handle gzip whiteouts correctly"
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Revert whiteout handling whilst we investigate image pull errors
with whiteouts. See confidential-containers#604

This reverts commit a54646f.

Signed-off-by: stevenhorsman <[email protected]>
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@stevenhorsman
stevenhorsman committed Jul 4, 2024
1 parent 1082c9c commit 53c2b7d
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1 change: 0 additions & 1 deletion Cargo.lock
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1 change: 0 additions & 1 deletion image-rs/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -61,7 +61,6 @@ tonic = { workspace = true, optional = true }
ttrpc = { workspace = true, features = ["async"], optional = true }
url = "2.5.2"
walkdir = "2"
xattr = "1.0"
zstd = "0.12"

nydus-api = { version = "0.3.0", optional = true }
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99 changes: 0 additions & 99 deletions image-rs/src/unpack.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,23 +2,16 @@
//
// SPDX-License-Identifier: Apache-2.0

use anyhow::anyhow;
use anyhow::Context;
use anyhow::{bail, Result};
use libc::timeval;
use log::warn;
use std::collections::HashMap;
use std::convert::TryInto;
use std::ffi::CString;
use std::fs;
use std::io;
use std::path::Path;
use tar::Archive;
use tar::Header;

// See https://github.com/opencontainers/image-spec/blob/main/layer.md#whiteouts
const WHITEOUT_PREFIX: &str = ".wh.";
const WHITEOUT_OPAQUE_DIR: &str = ".wh..wh..opq";

/// Unpack the contents of tarball to the destination path
pub fn unpack<R: io::Read>(input: R, destination: &Path) -> Result<()> {
Expand All @@ -40,11 +33,6 @@ pub fn unpack<R: io::Read>(input: R, destination: &Path) -> Result<()> {
let mut dirs: HashMap<CString, [timeval; 2]> = HashMap::default();
for file in archive.entries()? {
let mut file = file?;

if !convert_whiteout(&file.path()?, file.header(), destination)? {
continue;
}

file.unpack_in(destination)?;

// tar-rs crate only preserve timestamps of files,
Expand Down Expand Up @@ -95,69 +83,11 @@ pub fn unpack<R: io::Read>(input: R, destination: &Path) -> Result<()> {
Ok(())
}

fn convert_whiteout(path: &Path, header: &Header, destination: &Path) -> Result<bool> {
// Handle whiteout conversion
let name = path
.file_name()
.unwrap_or_default()
.to_str()
.ok_or(anyhow!("Invalid unicode in whiteout path: {:?}", path))?;

if name.starts_with(WHITEOUT_PREFIX) {
let parent = path
.parent()
.ok_or(anyhow!("Invalid whiteout parent for path: {:?}", path))?;

if name == WHITEOUT_OPAQUE_DIR {
let destination_parent = destination.join(parent);
xattr::set(destination_parent, "trusted.overlay.opaque", b"y")?;
return Ok(false);
}

let original_name = name
.strip_prefix(WHITEOUT_PREFIX)
.ok_or(anyhow!("Failed to strip whiteout prefix for: {}", name))?;
let original_path = parent.join(original_name);
let path = CString::new(format!(
"{}/{}",
destination.display(),
original_path.display()
))?;

let ret = unsafe { libc::mknod(path.as_ptr(), libc::S_IFCHR, 0) };
if ret != 0 {
bail!("mknod: {:?} error: {:?}", path, io::Error::last_os_error());
}

let uid: libc::uid_t = header
.uid()?
.try_into()
.map_err(|_| io::Error::new(io::ErrorKind::Other, "UID is too large!"))?;
let gid: libc::gid_t = header
.gid()?
.try_into()
.map_err(|_| io::Error::new(io::ErrorKind::Other, "GID is too large!"))?;

let ret = unsafe { libc::lchown(path.as_ptr(), uid, gid) };
if ret != 0 {
bail!(
"change ownership: {:?} error: {:?}",
path,
io::Error::last_os_error()
);
}
return Ok(false);
}

Ok(true)
}

#[cfg(test)]
mod tests {
use super::*;
use std::fs::File;
use std::io::prelude::*;
use std::os::unix::fs::FileTypeExt;

#[test]
fn test_unpack() {
Expand All @@ -175,33 +105,12 @@ mod tests {
ar.append_file("file.txt", &mut File::open(&path).unwrap())
.unwrap();

let path = tempdir
.path()
.join(WHITEOUT_PREFIX.to_owned() + "whiteout_file.txt");
File::create(&path).unwrap();
ar.append_file(
WHITEOUT_PREFIX.to_owned() + "whiteout_file.txt",
&mut File::open(&path).unwrap(),
)
.unwrap();

let path = tempdir.path().join("dir");
fs::create_dir(&path).unwrap();

filetime::set_file_mtime(&path, mtime).unwrap();
ar.append_path_with_name(&path, "dir").unwrap();

let path = tempdir.path().join("whiteout_dir");
fs::create_dir(&path).unwrap();
ar.append_path_with_name(&path, "whiteout_dir").unwrap();

let path = tempdir
.path()
.join("whiteout_dir/".to_owned() + WHITEOUT_OPAQUE_DIR);
fs::create_dir(&path).unwrap();
ar.append_path_with_name(&path, "whiteout_dir/".to_owned() + WHITEOUT_OPAQUE_DIR)
.unwrap();

// TODO: Add more file types like symlink, char, block devices.
let data = ar.into_inner().unwrap();
tempdir.close().unwrap();
Expand All @@ -218,19 +127,11 @@ mod tests {
let new_mtime = filetime::FileTime::from_last_modification_time(&metadata);
assert_eq!(mtime, new_mtime);

let path = destination.join("whiteout_file.txt");
let metadata = fs::metadata(path).unwrap();
assert!(metadata.file_type().is_char_device());

let path = destination.join("dir");
let metadata = fs::metadata(path).unwrap();
let new_mtime = filetime::FileTime::from_last_modification_time(&metadata);
assert_eq!(mtime, new_mtime);

let path = destination.join("whiteout_dir");
let opaque = xattr::get(path, "trusted.overlay.opaque").unwrap().unwrap();
assert_eq!(opaque, b"y");

// though destination already exists, it will be deleted
// and rewrite
assert!(unpack(data.as_slice(), destination).is_ok());
Expand Down

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