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// Copyright 2021 Colin Finck <colin@reactos.org>
// SPDX-License-Identifier: GPL-2.0-or-later
use crate::attribute::NtfsAttributeType;
use crate::error::{NtfsError, Result};
use crate::index_entry::{IndexNodeEntryRanges, NtfsIndexNodeEntries};
use crate::index_record::{IndexNodeHeader, INDEX_NODE_HEADER_SIZE};
use crate::structured_values::{NtfsStructuredValue, NtfsStructuredValueFromData};
use byteorder::{ByteOrder, LittleEndian};
use core::ops::Range;
use memoffset::offset_of;
/// Size of all [`IndexRootHeader`] fields plus some reserved bytes.
const INDEX_ROOT_HEADER_SIZE: usize = 16;
#[repr(C, packed)]
struct IndexRootHeader {
ty: u32,
collation_rule: u32,
index_record_size: u32,
clusters_per_index_record: i8,
}
#[derive(Clone, Debug)]
pub struct NtfsIndexRoot<'f> {
data: &'f [u8],
position: u64,
}
const LARGE_INDEX_FLAG: u8 = 0x01;
impl<'f> NtfsIndexRoot<'f> {
pub fn entries(&self) -> Result<NtfsIndexNodeEntries<'f>> {
let (entries_range, position) = self.entries_range_and_position();
let data = &self.data[entries_range];
Ok(NtfsIndexNodeEntries::new(data, position))
}
fn entries_range_and_position(&self) -> (Range<usize>, u64) {
let start = INDEX_ROOT_HEADER_SIZE as usize + self.index_entries_offset() as usize;
let end = INDEX_ROOT_HEADER_SIZE as usize + self.index_used_size() as usize;
let position = self.position + start as u64;
(start..end, position)
}
pub(crate) fn entry_ranges(&self) -> IndexNodeEntryRanges {
let (entries_range, position) = self.entries_range_and_position();
let entries_data = self.data[entries_range].to_vec();
let range = 0..entries_data.len();
IndexNodeEntryRanges::new(entries_data, range, position)
}
pub fn index_allocated_size(&self) -> u32 {
let start = INDEX_ROOT_HEADER_SIZE + offset_of!(IndexNodeHeader, allocated_size);
LittleEndian::read_u32(&self.data[start..])
}
fn index_entries_offset(&self) -> u32 {
let start = INDEX_ROOT_HEADER_SIZE + offset_of!(IndexNodeHeader, entries_offset);
LittleEndian::read_u32(&self.data[start..])
}
pub fn index_record_size(&self) -> u32 {
let start = offset_of!(IndexRootHeader, index_record_size);
LittleEndian::read_u32(&self.data[start..])
}
pub fn index_used_size(&self) -> u32 {
let start = INDEX_ROOT_HEADER_SIZE + offset_of!(IndexNodeHeader, index_size);
LittleEndian::read_u32(&self.data[start..])
}
/// Returns whether the index belonging to this Index Root is large enough
/// to need an extra Index Allocation attribute.
/// Otherwise, the entire index information is stored in this Index Root.
pub fn is_large_index(&self) -> bool {
let start = INDEX_ROOT_HEADER_SIZE + offset_of!(IndexNodeHeader, flags);
(self.data[start] & LARGE_INDEX_FLAG) != 0
}
pub fn position(&self) -> u64 {
self.position
}
fn validate_sizes(&self) -> Result<()> {
let (entries_range, _position) = self.entries_range_and_position();
if entries_range.start >= self.data.len() {
return Err(NtfsError::InvalidIndexRootEntriesOffset {
position: self.position,
expected: entries_range.start,
actual: self.data.len(),
});
}
if entries_range.end > self.data.len() {
return Err(NtfsError::InvalidIndexRootUsedSize {
position: self.position,
expected: entries_range.end,
actual: self.data.len(),
});
}
Ok(())
}
}
impl<'f> NtfsStructuredValue for NtfsIndexRoot<'f> {
const TY: NtfsAttributeType = NtfsAttributeType::IndexRoot;
}
impl<'f> NtfsStructuredValueFromData<'f> for NtfsIndexRoot<'f> {
fn from_data(data: &'f [u8], position: u64) -> Result<Self> {
if data.len() < INDEX_ROOT_HEADER_SIZE + INDEX_NODE_HEADER_SIZE {
return Err(NtfsError::InvalidStructuredValueSize {
position,
ty: NtfsAttributeType::IndexRoot,
expected: INDEX_ROOT_HEADER_SIZE,
actual: data.len(),
});
}
let index_root = Self { data, position };
index_root.validate_sizes()?;
Ok(index_root)
}
}
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