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// Copyright 2021 Colin Finck <colin@reactos.org>
// SPDX-License-Identifier: GPL-2.0-or-later
use crate::attribute_value::NtfsAttributeValue;
use crate::error::{NtfsError, Result};
use crate::index_entry::NtfsIndexNodeEntries;
use crate::ntfs::Ntfs;
use crate::record::RecordHeader;
use crate::structured_values::NewNtfsStructuredValue;
use crate::traits::NtfsReadSeek;
use crate::types::Vcn;
use binread::io::{Read, Seek, SeekFrom};
use binread::{BinRead, BinReaderExt};
/// Size of all [`IndexRecordHeader`] fields.
const INDEX_RECORD_HEADER_SIZE: u32 = 24;
#[allow(unused)]
#[derive(BinRead, Clone, Debug)]
struct IndexRecordHeader {
record_header: RecordHeader,
vcn: Vcn,
}
/// Size of all [`IndexNodeHeader`] fields plus some reserved bytes.
pub(crate) const INDEX_NODE_HEADER_SIZE: u64 = 16;
#[derive(BinRead, Clone, Debug)]
pub(crate) struct IndexNodeHeader {
pub(crate) entries_offset: u32,
pub(crate) index_size: u32,
pub(crate) allocated_size: u32,
pub(crate) flags: u8,
}
#[derive(Clone, Debug)]
pub struct NtfsIndexRecord<'n> {
ntfs: &'n Ntfs,
value: NtfsAttributeValue<'n>,
index_record_header: IndexRecordHeader,
index_node_header: IndexNodeHeader,
}
const HAS_SUBNODES_FLAG: u8 = 0x01;
impl<'n> NtfsIndexRecord<'n> {
pub(crate) fn new<T>(
ntfs: &'n Ntfs,
fs: &mut T,
value: NtfsAttributeValue<'n>,
index_record_size: u32,
) -> Result<Self>
where
T: Read + Seek,
{
let mut value_attached = value.clone().attach(fs);
let index_record_header = value_attached.read_le::<IndexRecordHeader>()?;
let index_node_header = value_attached.read_le::<IndexNodeHeader>()?;
let index_record = Self {
ntfs,
value,
index_record_header,
index_node_header,
};
index_record.validate_signature()?;
index_record.validate_sizes(index_record_size)?;
Ok(index_record)
}
pub fn entries<K, T>(&self, fs: &mut T) -> Result<NtfsIndexNodeEntries<'n, K>>
where
K: NewNtfsStructuredValue<'n>,
T: Read + Seek,
{
let offset = self.value.stream_position() + INDEX_RECORD_HEADER_SIZE as u64;
let start = offset + self.index_node_header.entries_offset as u64;
let end = offset + self.index_used_size() as u64;
let mut value = self.value.clone();
value.seek(fs, SeekFrom::Start(start))?;
Ok(NtfsIndexNodeEntries::new(self.ntfs, value, end))
}
/// Returns whether this index node has sub-nodes.
/// Otherwise, this index node is a leaf node.
pub fn has_subnodes(&self) -> bool {
(self.index_node_header.flags & HAS_SUBNODES_FLAG) != 0
}
pub fn index_allocated_size(&self) -> u32 {
self.index_node_header.allocated_size
}
pub fn index_used_size(&self) -> u32 {
self.index_node_header.index_size
}
fn validate_signature(&self) -> Result<()> {
let signature = &self.index_record_header.record_header.signature;
let expected = b"INDX";
if signature == expected {
Ok(())
} else {
Err(NtfsError::InvalidNtfsIndexSignature {
position: self.value.data_position().unwrap(),
expected,
actual: *signature,
})
}
}
fn validate_sizes(&self, index_record_size: u32) -> Result<()> {
// The total size allocated for this index record must not be larger than
// the size defined for all index records of this index.
let total_allocated_size = INDEX_RECORD_HEADER_SIZE + self.index_allocated_size();
if total_allocated_size > index_record_size {
return Err(NtfsError::InvalidNtfsIndexSize {
position: self.value.data_position().unwrap(),
expected: index_record_size,
actual: total_allocated_size,
});
}
// Furthermore, the total used size for this index record must not be
// larger than the total allocated size.
let total_used_size = INDEX_RECORD_HEADER_SIZE
+ self
.index_record_header
.record_header
.update_sequence_array_size()
+ self.index_used_size();
if total_used_size > total_allocated_size {
return Err(NtfsError::InvalidNtfsIndexSize {
position: self.value.data_position().unwrap(),
expected: total_allocated_size,
actual: total_used_size,
});
}
Ok(())
}
pub fn vcn(&self) -> Vcn {
self.index_record_header.vcn
}
}
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