Function prepare_configfs

tdx-attest/src/linux.rs:335–384

()

}

fn prepare_configfs() -> Result<String> {
    if let Ok(path) = std::env::var(CONFIGFS_PATH_ENV) {
        if path.len() < 240 && Path::new(&path).is_dir() && verify_configfs_provider(&path)? {
            return Ok(path);
        }
        return Err(TdxAttestError::NotSupported(format!(
            "invalid configfs path from env: {path}"
        )));
    }

    let default_path = CONFIGFS_DEFAULT;
    if Path::new(default_path).is_dir() && verify_configfs_provider(default_path)? {
        return Ok(default_path.to_string());
    }

    {
        let mut tried = CONFIGFS_MKDIR_TRIED
            .lock()
            .map_err(|_| TdxAttestError::Busy)?;
        if *tried {
            return Err(TdxAttestError::NotSupported(
                "configfs already tried".to_string(),
            ));
        }
        *tried = true;
    }

    if !Path::new(CONFIGFS_BASE).is_dir() {
        return Err(TdxAttestError::NotSupported(format!(
            "configfs base not found: {CONFIGFS_BASE}"
        )));
    }

    if fs::create_dir(default_path).is_ok() || Path::new(default_path).is_dir() {
        let provider_path = format!("{}/provider", default_path);
        for i in 0..5 {
            if Path::new(&provider_path).exists() {
                if verify_configfs_provider(default_path)? {
                    return Ok(default_path.to_string());
                }
                break;
            }
            thread::sleep(Duration::from_micros(i as u64));
        }
    }

    Err(TdxAttestError::NotSupported(format!(
        "failed to prepare configfs: {default_path}"
    )))
}

fn verify_configfs_provider(path: &str) -> Result<bool> {
    let provider_path = format!("{}/provider", path);