extract: restore directory modification times from the archive

Cargo.toml

@@ -34,6 +34,7 @@ chrono = { version = "0.4.37", default-features = false, features = [
 ] }
 clap = { version = "4.4", features = ["wrap_help", "cargo"] }
 ctor = "1.0.0"
+filetime = "0.2"
 flate2 = { version = "1.1.10", default-features = false, features = ["zlib-rs"] }
 phf = "0.14.0"
 phf_codegen = "0.14.0"

src/uu/tar/Cargo.toml

@@ -14,6 +14,7 @@ categories = ["command-line-utilities"]
 [dependencies]
 chrono = { workspace = true }
 clap = { workspace = true }
+filetime = { workspace = true }
 flate2 = { workspace = true }
 regex = { workspace = true }
 tar = { workspace = true }

src/uu/tar/src/errors.rs

@@ -68,6 +68,10 @@ pub enum TarError {
     #[error("tar: Refusing to write archive contents to terminal (missing -f option?)")]
     RefuseWriteArchiveToTerminal,
 
+    /// The modification time of an extracted directory could not be set
+    #[error("tar: {path}: Cannot utime: {source}")]
+    CannotUtime { path: PathBuf, source: io::Error },
+
     /// A member name with a `..` component, which is not extracted
     #[error("tar: {path}: Member name contains '..'")]
     MemberNameContainsDotDot { path: PathBuf },

src/uu/tar/src/operations/extract.rs

@@ -6,6 +6,7 @@
 use crate::compression::open_archive_reader;
 use crate::errors::{finish_after_previous_errors, report_recoverable, TarError};
 use crate::CompressionMode;
+use filetime::FileTime;
 use std::collections::HashSet;
 use std::io::Read;
 use std::io::{self, BufWriter, Write};
@@ -80,7 +81,17 @@ pub fn extract_archive(
     // Children before parents, so a read-only parent is restored last
     directories.sort_by(|a, b| b.0.cmp(&a.0));
     for (path, mut entry) in directories {
-        refused_member |= unpack_entry(&mut entry, path, &mut out)?;
+        let mtime = entry.header().mtime().ok();
+        let refused = unpack_entry(&mut entry, path.clone(), &mut out)?;
+        refused_member |= refused;
+        // The archive's mtime, as GNU tar restores it (tar-rs only does it for files)
+        if let (false, Some(mtime)) = (refused, mtime) {
+            if let Err(e) = set_directory_mtime(&path, mtime) {
+                out.flush().map_err(TarError::Io)?;
+                report_recoverable(&TarError::CannotUtime { path, source: e })?;
+                refused_member = true;
+            }
+        }
     }
 
     out.flush().map_err(TarError::Io)?;
@@ -130,6 +141,22 @@ fn unpack_entry<R: Read>(
     Ok(!unpacked)
 }
 
+/// Sets the mtime of the directory `unpack_in` extracted for the member `path`.
+fn set_directory_mtime(path: &Path, mtime: u64) -> io::Result<()> {
+    // `unpack_in` drops the root, `.` and prefix components of member names
+    let dst: PathBuf = path
+        .components()
+        .filter(|c| matches!(c, Component::Normal(_)))
+        .collect();
+    let dst = if dst.as_os_str().is_empty() {
+        PathBuf::from(".")
+    } else {
+        dst
+    };
+    // Negative times come back from tar-rs as large u64 values; cast like it does
+    filetime::set_file_mtime(&dst, FileTime::from_unix_time(mtime as i64, 0))
+}
+
 #[cfg(test)]
 #[path = "extract_tests.rs"]
 mod tests;

tests/by-util/test_tar.rs

@@ -659,6 +659,44 @@ fn test_extract_nested_read_only_directories() {
     assert_eq!(child & 0o777, 0o555);
 }
 
+#[test]
+fn test_extract_keeps_directory_mtime() {
+    let (at, mut ucmd) = at_and_ucmd!();
+    at.mkdir("out");
+
+    let mut tar_bytes = Vec::new();
+    {
+        let mut builder = TarRsBuilder::new(&mut tar_bytes);
+        let mut header = TarRsHeader::new_gnu();
+        header.set_entry_type(tar_rs_crate::EntryType::Directory);
+        header.set_mode(0o755);
+        header.set_mtime(1_000_000_000);
+        header.set_size(0);
+        builder
+            .append_data(&mut header, "dir/", std::io::empty())
+            .unwrap();
+        let mut header = TarRsHeader::new_gnu();
+        header.set_mode(0o644);
+        header.set_mtime(1_000_000_000);
+        header.set_size(1);
+        builder
+            .append_data(&mut header, "dir/f", Cursor::new("x"))
+            .unwrap();
+        builder.finish().unwrap();
+    }
+    at.write_bytes("dir.tar", &tar_bytes);
+
+    ucmd.args(&["-xf", "../dir.tar"])
+        .current_dir(at.plus("out"))
+        .succeeds();
+
+    let mtime = at.metadata("out/dir").modified().unwrap();
+    assert_eq!(
+        mtime,
+        std::time::UNIX_EPOCH + std::time::Duration::from_secs(1_000_000_000)
+    );
+}
+
 #[test]
 fn test_extract_nonexistent_archive() {
     new_ucmd!()