Function boot_option_bytes

dstack-mr/src/uefi_var.rs:73–95

Build the raw bytes of a `Boot####` UEFI variable — the on-the-wire form of `EFI_LOAD_OPTION { Attributes, FilePathListLength, Description, FilePathList, OptionalData }`. The description is automatically NUL-terminated in UTF-16LE.

(
    attributes: u32,
    description: &str,
    file_path_nodes: &[DevicePathNode<'_>],
    optional_data: &[u8],
)

///
/// The description is automatically NUL-terminated in UTF-16LE.
pub fn boot_option_bytes(
    attributes: u32,
    description: &str,
    file_path_nodes: &[DevicePathNode<'_>],
    optional_data: &[u8],
) -> Vec<u8> {
    // Serialise the device-path list first so we know its length.
    let mut file_path = Vec::new();
    for node in file_path_nodes {
        node.write_to(&mut file_path);
    }

    let mut desc = utf16_encode(description);
    desc.extend_from_slice(&[0x00, 0x00]); // NUL terminator

    let mut out = Vec::with_capacity(4 + 2 + desc.len() + file_path.len() + optional_data.len());
    out.extend_from_slice(&attributes.to_le_bytes());
    out.extend_from_slice(&(file_path.len() as u16).to_le_bytes());
    out.extend_from_slice(&desc);
    out.extend_from_slice(&file_path);
    out.extend_from_slice(optional_data);
    out
}

#[cfg(test)]
mod tests {