uutils/coreutils · warning · SmackError::LabelRetrievalFailure

smack-error-no-label-set

Error message

smack-error-no-label-set

What it means

get_smack_label_for_path reads the security.SMACK64 extended attribute on Smack-enabled systems. If the attribute exists but is unset (xattr returns Some with... Ok(None) meaning no value), it wraps a NotFound io error carrying 'smack-error-no-label-set' in SmackError::LabelRetrievalFailure.

Solutions

1. Set a label with `chsmack -a <label> <path>` before reading
2. Fall back to a default label in your code when LabelRetrievalFailure(NotFound) is returned
3. Verify the filesystem supports Smack labeling

Example fix

// before
let label = get_smack_label_for_path(path)?;
// after
let label = get_smack_label_for_path(path).unwrap_or_else(|_| "_".to_string());

// xattr presence check (Linux)
fn has_smack64(path: &Path) -> bool {
    std::path::Path::new("/sys/fs/smackfs").exists() &&
        std::fs::read(path).is_ok() // filesystem reachable; label check via xattr crate
}

match get_smack_label_for_path(path) {
    Err(SmackError::LabelRetrievalFailure(e)) if e.kind() == std::io::ErrorKind::NotFound => default_label(),
    Ok(label) => label,
    Err(e) => return Err(e.into()),
}

When it happens

Trigger: Calling get_smack_label_for_path on a file that has the SMACK64 xattr slot empty or no label assigned — i.e. the file was never labeled by smack.-label or inherited no label.

Common situations: Files created on non-Smack filesystems mounted on a Smack system; freshly extracted archives lacking xattrs; tmpfs volumes without Smack labeling.

Understand the failure class

Background: "File not found" and ENOENT errors: why libraries can't find a file that should exist — this error's family across 50 libraries.

Related errors

• mv-error-dest-appeared (path)

AI-assisted analysis of uutils/coreutils@92995feca2 (2026-09-20). Data as JSON: /api/errors/5e41cf42eadda8d9. Report an issue: GitHub.

Appendix: source

Thrown at src/uucore/src/lib/features/smack.rs:89

pub fn set_smack_label_for_self(label: &str) -> Result<(), SmackError> {
    if !is_smack_enabled() {
        return Err(SmackError::SmackNotEnabled);
    }

    fs::File::create("/proc/self/attr/current")
        .and_then(|mut f| f.write_all(label.as_bytes()))
        .map_err(|e| SmackError::LabelSetFailure(label.to_string(), e))
}

/// Gets the SMACK label for a filesystem path via xattr.
pub fn get_smack_label_for_path(path: &Path) -> Result<String, SmackError> {
    if !is_smack_enabled() {
        return Err(SmackError::SmackNotEnabled);
    }

    match xattr::get(path, "security.SMACK64") {
        Ok(Some(value)) => Ok(String::from_utf8_lossy(&value).trim().to_string()),
        Ok(None) => Err(SmackError::LabelRetrievalFailure(io::Error::new(
            io::ErrorKind::NotFound,
            translate!("smack-error-no-label-set"),
        ))),
        Err(e) => Err(SmackError::LabelRetrievalFailure(e)),
    }
}

/// Sets the SMACK label for a filesystem path via xattr.
pub fn set_smack_label_for_path(path: &Path, label: &str) -> Result<(), SmackError> {
    if !is_smack_enabled() {
        return Err(SmackError::SmackNotEnabled);
    }

    xattr::set(path, "security.SMACK64", label.as_bytes())
        .map_err(|e| SmackError::LabelSetFailure(label.to_string(), e))
}

/// Sets SMACK label for a new path, calling cleanup on failure.

View on GitHub (pinned to 92995feca2)