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use crate::err::{Error, Result};
use byteorder::{LittleEndian, ReadBytesExt};
use encoding::all::UTF_16LE;
use encoding::{DecoderTrap, Encoding};
use serde::Serialize;
use std::io::{Read, Seek, SeekFrom};
use winstructs::ntfs::mft_reference::MftReference;
/// The AttributeListAttr represents the $20 attribute, which contains a list
/// of attribute entries in child entries.
///
#[derive(Serialize, Clone, Debug)]
pub struct AttributeListAttr {
/// A list of AttributeListEntry that make up this AttributeListAttr
pub entries: Vec<AttributeListEntry>,
}
impl AttributeListAttr {
/// Read AttributeListAttr from stream. Stream should be the size of the attribute's data itself
/// if no stream_size is passed in.
///
/// # Example
///
/// Parse a raw buffer.
///
/// ```
/// use mft::attribute::x20::AttributeListAttr;
/// # use std::io::Cursor;
/// let attribute_content_buffer: &[u8] = &[
/// 0x10,0x00,0x00,0x00,0x20,0x00,0x00,0x1A,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
/// 0x23,0x27,0x00,0x00,0x00,0x00,0x01,0x00,0x00,0x00,0x12,0x07,0x80,0xF8,0xFF,0xFF,
/// 0x30,0x00,0x00,0x00,0x20,0x00,0x00,0x1A,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
/// 0x23,0x27,0x00,0x00,0x00,0x00,0x01,0x00,0x03,0x00,0x00,0x00,0x69,0x00,0x6E,0x00,
/// 0x30,0x00,0x00,0x00,0x20,0x00,0x00,0x1A,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
/// 0x0F,0xCF,0x01,0x00,0x00,0x00,0x02,0x00,0x00,0x00,0x8A,0x0C,0xA0,0xF8,0xFF,0xFF,
/// 0x90,0x00,0x00,0x00,0x28,0x00,0x04,0x1A,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
/// 0x0F,0xCF,0x01,0x00,0x00,0x00,0x02,0x00,0x01,0x00,0x24,0x00,0x49,0x00,0x33,0x00,
/// 0x30,0x00,0x79,0x00,0x73,0x00,0xAD,0xEF,0xA0,0x00,0x00,0x00,0x28,0x00,0x04,0x1A,
/// 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x0F,0xCF,0x01,0x00,0x00,0x00,0x02,0x00,
/// 0x02,0x00,0x24,0x00,0x49,0x00,0x33,0x00,0x30,0x00,0x00,0x00,0x00,0x00,0x78,0x56,
/// 0xB0,0x00,0x00,0x00,0x28,0x00,0x04,0x1A,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
/// 0x0F,0xCF,0x01,0x00,0x00,0x00,0x02,0x00,0x03,0x00,0x24,0x00,0x49,0x00,0x33,0x00,
/// 0x30,0x00,0x00,0x00,0x00,0x00,0x65,0x00,0x00,0x01,0x00,0x00,0x30,0x00,0x09,0x1A,
/// 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x23,0x27,0x00,0x00,0x00,0x00,0x01,0x00,
/// 0x08,0x00,0x24,0x00,0x54,0x00,0x58,0x00,0x46,0x00,0x5F,0x00,0x44,0x00,0x41,0x00,
/// 0x54,0x00,0x41,0x00,0x00,0x00,0x00,0x00
/// ];
///
/// let attribute_list = AttributeListAttr::from_stream(
/// &mut Cursor::new(attribute_content_buffer),
/// None
/// ).unwrap();
///
/// assert_eq!(attribute_list.entries.len(), 7);
/// ```
pub fn from_stream<S: Read + Seek>(
mut stream: &mut S,
stream_size: Option<u64>,
) -> Result<AttributeListAttr> {
let mut start_offset = stream.stream_position()?;
let end_offset = match stream_size {
Some(s) => s,
None => {
// If no stream size was passed in we seek to the end of the stream,
// then tell to get the ending offset, then seek back to the start,
// thus, its better to just pass the stream size.
stream.seek(SeekFrom::End(0))?;
let offset = stream.stream_position()?;
stream.rewind()?;
offset
}
};
let mut entries: Vec<AttributeListEntry> = Vec::new();
// iterate attribute content parsing attribute list entries
while start_offset < end_offset {
// parse the entry from the stream
let attr_entry = AttributeListEntry::from_stream(&mut stream)?;
// update the starting offset
start_offset += attr_entry.record_length as u64;
// add attribute entry to entries vec
entries.push(attr_entry);
// seek the stream to next start offset to avoid padding
stream.seek(SeekFrom::Start(start_offset))?;
}
Ok(Self { entries })
}
}
/// An AttributeListAttr is made up off multiple AttributeListEntry structs.
/// <https://docs.microsoft.com/en-us/windows/win32/devnotes/attribute-list-entry>
///
#[derive(Serialize, Clone, Debug)]
pub struct AttributeListEntry {
/// The attribute code
pub attribute_type: u32,
/// This entry length
pub record_length: u16,
/// Attribute name length (0 means no name)
pub name_length: u8,
/// Attribute name offset
pub name_offset: u8,
/// This member is zero unless the attribute requires multiple file record
/// segments and unless this entry is a reference to a segment other than the first one.
/// In this case, this value is the lowest VCN that is described by the referenced segment.
pub lowest_vcn: u64,
/// The segments MFT reference
pub segment_reference: MftReference,
/// The attribute's id
pub reserved: u16,
/// The attribute's name
pub name: String,
}
impl AttributeListEntry {
/// Create AttributeListEntry from a stream.
///
/// # Example
///
/// Parse a raw buffer.
///
/// ```
/// use mft::attribute::x20::AttributeListEntry;
/// # use std::io::Cursor;
/// let attribute_buffer: &[u8] = &[
/// 0x10,0x00,0x00,0x00,0x20,0x00,0x00,0x1A,
/// 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
/// 0x23,0x27,0x00,0x00,0x00,0x00,0x01,0x00,
/// 0x00,0x00,0x12,0x07,0x80,0xF8,0xFF,0xFF
/// ];
///
/// let attribute_entry = AttributeListEntry::from_stream(
/// &mut Cursor::new(attribute_buffer)
/// ).unwrap();
///
/// assert_eq!(attribute_entry.attribute_type, 16);
/// assert_eq!(attribute_entry.record_length, 32);
/// assert_eq!(attribute_entry.name_length, 0);
/// assert_eq!(attribute_entry.name_offset, 26);
/// assert_eq!(attribute_entry.lowest_vcn, 0);
/// assert_eq!(attribute_entry.segment_reference.entry, 10019);
/// assert_eq!(attribute_entry.segment_reference.sequence, 1);
/// assert_eq!(attribute_entry.reserved, 0);
/// assert_eq!(attribute_entry.name, "".to_string());
/// ```
pub fn from_stream<S: Read + Seek>(stream: &mut S) -> Result<AttributeListEntry> {
let start_offset = stream.stream_position()?;
let attribute_type = stream.read_u32::<LittleEndian>()?;
let record_length = stream.read_u16::<LittleEndian>()?;
let name_length = stream.read_u8()?;
let name_offset = stream.read_u8()?;
let lowest_vcn = stream.read_u64::<LittleEndian>()?;
let segment_reference =
MftReference::from_reader(stream).map_err(Error::failed_to_read_mft_reference)?;
let reserved = stream.read_u16::<LittleEndian>()?;
let name = if name_length > 0 {
stream.seek(SeekFrom::Start(start_offset + u64::from(name_offset)))?;
let mut name_buffer = vec![0; name_length as usize * 2];
stream.read_exact(&mut name_buffer)?;
match UTF_16LE.decode(&name_buffer, DecoderTrap::Ignore) {
Ok(s) => s,
Err(_e) => return Err(Error::InvalidFilename {}),
}
} else {
String::new()
};
Ok(AttributeListEntry {
attribute_type,
record_length,
name_length,
name_offset,
lowest_vcn,
segment_reference,
reserved,
name,
})
}
}