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WIP: Support non-standard images #174

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Mar 5, 2023
Merged

WIP: Support non-standard images #174

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4 changes: 3 additions & 1 deletion src/dir.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,9 +11,11 @@ use std::path::PathBuf;
use deku::prelude::*;

use crate::inode::InodeId;
use crate::kind::Kind;

#[derive(Debug, DekuRead, DekuWrite, Clone, Default, PartialEq, Eq)]
#[deku(endian = "little")]
#[deku(ctx = "kind: Kind")]
#[deku(endian = "kind.type_endian")]
pub struct Dir {
/// Number of entries following the header.
pub(crate) count: u32,
Expand Down
42 changes: 12 additions & 30 deletions src/entry.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ use crate::inode::{
InodeInner,
};
use crate::metadata::MetadataWriter;
use crate::squashfs::SuperBlock;
use crate::squashfs::{Kind, SuperBlock};
use crate::{
NodeHeader, SquashfsBlockDevice, SquashfsCharacterDevice, SquashfsDir, SquashfsSymlink,
};
Expand Down Expand Up @@ -43,6 +43,7 @@ impl<'a> Entry<'a> {
block_offset: u16,
block_index: u32,
superblock: &SuperBlock,
kind: Kind,
) -> Self {
let dir_inode = Inode {
id: InodeId::BasicDirectory,
Expand All @@ -59,10 +60,11 @@ impl<'a> Entry<'a> {
}),
};

dir_inode.to_bytes(name.as_bytes(), inode_writer, superblock)
dir_inode.to_bytes(name.as_bytes(), inode_writer, superblock, kind)
}

/// Write data and metadata for file node
#[allow(clippy::too_many_arguments)]
pub fn file(
node_path: &'a OsStr,
header: &NodeHeader,
Expand All @@ -71,6 +73,7 @@ impl<'a> Entry<'a> {
file_size: usize,
added: &Added,
superblock: &SuperBlock,
kind: Kind,
) -> Self {
let basic_file = match added {
Added::Data {
Expand Down Expand Up @@ -106,7 +109,7 @@ impl<'a> Entry<'a> {
inner: InodeInner::BasicFile(basic_file),
};

file_inode.to_bytes(node_path.as_bytes(), inode_writer, superblock)
file_inode.to_bytes(node_path.as_bytes(), inode_writer, superblock, kind)
}

/// Write data and metadata for symlink node
Expand All @@ -116,6 +119,7 @@ impl<'a> Entry<'a> {
inode: u32,
inode_writer: &mut MetadataWriter,
superblock: &SuperBlock,
kind: Kind,
) -> Self {
let link = symlink.link.as_os_str().as_bytes();
let sym_inode = Inode {
Expand All @@ -131,7 +135,7 @@ impl<'a> Entry<'a> {
}),
};

sym_inode.to_bytes(node_path.as_bytes(), inode_writer, superblock)
sym_inode.to_bytes(node_path.as_bytes(), inode_writer, superblock, kind)
}

/// Write data and metadata for char device node
Expand All @@ -141,6 +145,7 @@ impl<'a> Entry<'a> {
inode: u32,
inode_writer: &mut MetadataWriter,
superblock: &SuperBlock,
kind: Kind,
) -> Self {
let char_inode = Inode {
id: InodeId::BasicCharacterDevice,
Expand All @@ -154,7 +159,7 @@ impl<'a> Entry<'a> {
}),
};

char_inode.to_bytes(node_path.as_bytes(), inode_writer, superblock)
char_inode.to_bytes(node_path.as_bytes(), inode_writer, superblock, kind)
}

/// Write data and metadata for block device node
Expand All @@ -164,6 +169,7 @@ impl<'a> Entry<'a> {
inode: u32,
inode_writer: &mut MetadataWriter,
superblock: &SuperBlock,
kind: Kind,
) -> Self {
let block_inode = Inode {
id: InodeId::BasicBlockDevice,
Expand All @@ -177,7 +183,7 @@ impl<'a> Entry<'a> {
}),
};

block_inode.to_bytes(node_path.as_bytes(), inode_writer, superblock)
block_inode.to_bytes(node_path.as_bytes(), inode_writer, superblock, kind)
}
}

Expand Down Expand Up @@ -266,31 +272,7 @@ impl<'a> Entry<'a> {

#[cfg(test)]
mod tests {
use std::io::Write;

use super::*;
use crate::compressor::Compressor;
use crate::metadata::{MetadataWriter, METADATA_MAXSIZE};

#[test]
#[cfg(feature = "xz")]
fn test_mwriter() {
let bytes = [0xffu8; METADATA_MAXSIZE - 3];

let mut mwriter = MetadataWriter::new(Compressor::Xz, None, 0x2000);

mwriter.write_all(&bytes).unwrap();
assert_eq!(0, mwriter.metadata_start);
assert_eq!(bytes, &*mwriter.uncompressed_bytes);
assert!(mwriter.compressed_bytes.is_empty());

let bytes = [0x11u8; 6];

mwriter.write_all(&bytes).unwrap();
assert_eq!(0x6e, mwriter.metadata_start);
assert_eq!(bytes[3..], mwriter.uncompressed_bytes);
assert_eq!(mwriter.compressed_bytes[0].len(), 0x6c);
}

#[test]
fn test_entry() {
Expand Down
15 changes: 14 additions & 1 deletion src/filesystem/reader.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,12 +7,13 @@ use crate::error::SquashfsError;
use crate::fragment::Fragment;
use crate::inode::BasicFile;
use crate::reader::{ReadSeek, SquashfsReaderWithOffset};
use crate::squashfs::{Cache, Id};
use crate::squashfs::{Cache, Id, Kind};
use crate::{Node, Squashfs, SquashfsDir, SquashfsFileReader};

/// Representation of SquashFS filesystem after read from image
#[derive(Debug)]
pub struct FilesystemReader<R: ReadSeek> {
pub kind: Kind,
/// See [`SuperBlock`].`block_size`
pub block_size: u32,
/// See [`SuperBlock`].`block_log`
Expand All @@ -39,6 +40,8 @@ pub struct FilesystemReader<R: ReadSeek> {

impl<R: ReadSeek> FilesystemReader<R> {
/// Call [`Squashfs::from_reader`], then [`Squashfs::into_filesystem_reader`]
///
/// With default kind: [`crate::kind::LE_V4_0`] and offset `0`.
pub fn from_reader(reader: R) -> Result<Self, SquashfsError> {
let squashfs = Squashfs::from_reader(reader)?;
squashfs.into_filesystem_reader()
Expand All @@ -51,6 +54,16 @@ impl<R: ReadSeek> FilesystemReader<SquashfsReaderWithOffset<R>> {
let squashfs = Squashfs::from_reader_with_offset(reader, offset)?;
squashfs.into_filesystem_reader()
}

/// Same as [`Self::from_reader_with_offset`], but setting custom `kind`
pub fn from_reader_with_offset_and_kind(
reader: R,
offset: u64,
kind: Kind,
) -> Result<Self, SquashfsError> {
let squashfs = Squashfs::from_reader_with_offset_and_kind(reader, offset, kind)?;
squashfs.into_filesystem_reader()
}
}

impl<R: ReadSeek> FilesystemReader<R> {
Expand Down
63 changes: 44 additions & 19 deletions src/filesystem/writer.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,8 @@ use std::cell::RefCell;
use std::io::{Read, Seek, SeekFrom, Write};
use std::path::PathBuf;

use deku::DekuContainerWrite;
use deku::bitvec::BitVec;
use deku::DekuWrite;
use tracing::{info, instrument, trace};

use crate::compressor::{CompressionOptions, Compressor};
Expand All @@ -11,6 +12,7 @@ use crate::error::SquashfsError;
use crate::filesystem::dummy::DummyReadSeek;
use crate::filesystem::node::SquashfsSymlink;
use crate::fragment::Fragment;
use crate::kind::Kind;
use crate::metadata::{self, MetadataWriter};
use crate::reader::{ReadSeek, WriteSeek};
use crate::squashfs::{Id, SuperBlock};
Expand All @@ -23,6 +25,7 @@ use crate::{
/// Representation of SquashFS filesystem to be written back to an image
#[derive(Debug)]
pub struct FilesystemWriter<'a, R: ReadSeek = DummyReadSeek> {
pub kind: Kind,
/// See [`SuperBlock`].`block_size`
pub block_size: u32,
/// See [`SuperBlock`].`block_log`
Expand Down Expand Up @@ -68,6 +71,7 @@ impl<'a, R: ReadSeek> FilesystemWriter<'a, R> {
})
.collect::<Result<_, SquashfsError>>()?;
Ok(Self {
kind: reader.kind,
block_size: reader.block_size,
block_log: reader.block_log,
compressor: reader.compressor,
Expand Down Expand Up @@ -230,7 +234,7 @@ impl<'a, R: ReadSeek> FilesystemWriter<'a, R> {
/// correct fields from `Filesystem`, and the data after that contains the nodes.
#[instrument(skip_all)]
pub fn write<W: Write + Seek>(&self, w: &mut W) -> Result<(), SquashfsError> {
let mut superblock = SuperBlock::new(self.compressor);
let mut superblock = SuperBlock::new(self.compressor, self.kind);

trace!("{:#02x?}", self.nodes);
info!("Creating Tree");
Expand All @@ -240,8 +244,9 @@ impl<'a, R: ReadSeek> FilesystemWriter<'a, R> {
// Empty Squashfs Superblock
w.write_all(&[0x00; 96])?;
let mut data_writer = DataWriter::new(self.compressor, None, self.block_size);
let mut inode_writer = MetadataWriter::new(self.compressor, None, self.block_size);
let mut dir_writer = MetadataWriter::new(self.compressor, None, self.block_size);
let mut inode_writer =
MetadataWriter::new(self.compressor, None, self.block_size, self.kind);
let mut dir_writer = MetadataWriter::new(self.compressor, None, self.block_size, self.kind);

info!("Creating Inodes and Dirs");
//trace!("TREE: {:#02x?}", tree);
Expand All @@ -253,7 +258,7 @@ impl<'a, R: ReadSeek> FilesystemWriter<'a, R> {

info!("Writing Other stuff");
let (_, root_inode) =
tree.write_inode_dir(&mut inode_writer, &mut dir_writer, 0, superblock)?;
tree.write_inode_dir(&mut inode_writer, &mut dir_writer, 0, superblock, self.kind)?;

superblock.root_inode = root_inode;
superblock.inode_count = self.nodes.len() as u32 + 1; // + 1 for the "/"
Expand All @@ -270,20 +275,21 @@ impl<'a, R: ReadSeek> FilesystemWriter<'a, R> {
dir_writer.finalize(w)?;

info!("Writing Frag Lookup Table");
Self::write_frag_table(w, data_writer.fragment_table, &mut superblock)?;
self.write_frag_table(w, data_writer.fragment_table, &mut superblock)?;

info!("Writing Id Lookup Table");
Self::write_id_table(w, &self.id_table, &mut superblock)?;
self.write_id_table(w, &self.id_table, &mut superblock)?;

info!("Finalize Superblock and End Bytes");
Self::finalize(w, &mut superblock)?;
self.finalize(w, &mut superblock)?;

info!("Superblock: {:#02x?}", superblock);
info!("Success");
Ok(())
}

fn finalize<W: Write + Seek>(
&self,
w: &mut W,
superblock: &mut SuperBlock,
) -> Result<(), SquashfsError> {
Expand All @@ -299,14 +305,17 @@ impl<'a, R: ReadSeek> FilesystemWriter<'a, R> {
info!("Writing Superblock");
trace!("{:#02x?}", superblock);
w.rewind()?;
w.write_all(&superblock.to_bytes()?)?;
let mut bv = BitVec::new();
superblock.write(&mut bv, self.kind)?;
w.write_all(bv.as_raw_slice())?;

info!("Writing Finished");

Ok(())
}

fn write_id_table<W: Write + Seek>(
&self,
w: &mut W,
id_table: &Option<Vec<Id>>,
write_superblock: &mut SuperBlock,
Expand All @@ -315,37 +324,53 @@ impl<'a, R: ReadSeek> FilesystemWriter<'a, R> {
let id_table_dat = w.stream_position()?;
let mut id_bytes = Vec::with_capacity(id.len() * ((u32::BITS / 8) as usize));
for i in id {
let bytes = i.to_bytes()?;
id_bytes.write_all(&bytes)?;
let mut bv = BitVec::new();
i.write(&mut bv, self.kind)?;
id_bytes.write_all(bv.as_raw_slice())?;
}
let metadata_len = metadata::set_if_uncompressed(id_bytes.len() as u16).to_le_bytes();
w.write_all(&metadata_len)?;
// write metdata_length
let mut bv = BitVec::new();
metadata::set_if_uncompressed(id_bytes.len() as u16)
.write(&mut bv, self.kind.data_endian)?;
w.write_all(bv.as_raw_slice())?;
w.write_all(&id_bytes)?;
write_superblock.id_table = w.stream_position()?;
write_superblock.id_count = id.len() as u16;
w.write_all(&id_table_dat.to_le_bytes())?;

let mut bv = BitVec::new();
id_table_dat.write(&mut bv, self.kind.type_endian)?;
w.write_all(bv.as_raw_slice())?;
}

Ok(())
}

fn write_frag_table<W: Write + Seek>(
&self,
w: &mut W,
frag_table: Vec<Fragment>,
write_superblock: &mut SuperBlock,
) -> Result<(), SquashfsError> {
let frag_table_dat = w.stream_position()?;
let mut frag_bytes = Vec::with_capacity(frag_table.len() * fragment::SIZE);
for f in &frag_table {
let bytes = f.to_bytes()?;
frag_bytes.write_all(&bytes)?;
let mut bv = BitVec::new();
f.write(&mut bv, self.kind)?;
frag_bytes.write_all(bv.as_raw_slice())?;
}
let metadata_len = metadata::set_if_uncompressed(frag_bytes.len() as u16).to_le_bytes();
w.write_all(&metadata_len)?;
// write metdata_length
let mut bv = BitVec::new();
metadata::set_if_uncompressed(frag_bytes.len() as u16)
.write(&mut bv, self.kind.data_endian)?;
w.write_all(bv.as_raw_slice())?;

w.write_all(&frag_bytes)?;
write_superblock.frag_table = w.stream_position()?;
write_superblock.frag_count = frag_table.len() as u32;
w.write_all(&frag_table_dat.to_le_bytes())?;

let mut bv = BitVec::new();
frag_table_dat.write(&mut bv, self.kind.type_endian)?;
w.write_all(bv.as_raw_slice())?;

Ok(())
}
Expand Down
3 changes: 2 additions & 1 deletion src/fragment.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,12 +3,13 @@
use deku::prelude::*;

use crate::data::DataSize;
use crate::kind::Kind;

pub(crate) const SIZE: usize =
std::mem::size_of::<u64>() + std::mem::size_of::<u32>() + std::mem::size_of::<u32>();

#[derive(Copy, Clone, Debug, PartialEq, Eq, DekuRead, DekuWrite)]
#[deku(endian = "little")]
#[deku(endian = "kind.type_endian", ctx = "kind: Kind")]
pub struct Fragment {
pub start: u64,
pub size: DataSize,
Expand Down
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