Lucas RayanandClaude Sonnet 5.5
0ced7b725a
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
281 lines
11 KiB
Rust
281 lines
11 KiB
Rust
//! Btrfs: imagens criadas com mkfs.btrfs --rootdir; exclusão simulada como o COW faz
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//! (nova versão da folha em outro bloco, a antiga continua no disco).
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mod common;
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use common::*;
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use guara_core::fs::btrfs::{crc32c, live_paths, lzo1x_decompress};
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use guara_core::source::{FileSource, Source};
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use guara_core::*;
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use std::path::{Path, PathBuf};
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use std::process::Command;
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fn have(t: &str) -> bool {
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Command::new("sh").args(["-c", &format!("command -v {t}")]).output().map(|o| o.status.success()).unwrap_or(false)
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}
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fn data(seed: u64, n: usize) -> Vec<u8> {
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let mut x = seed | 1;
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(0..n)
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.map(|_| {
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x ^= x << 13;
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x ^= x >> 7;
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x ^= x << 17;
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(x >> 24) as u8
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})
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.collect()
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}
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struct Img {
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_dir: tempfile::TempDir,
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path: PathBuf,
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files: Vec<(&'static str, Vec<u8>)>,
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}
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fn build() -> Option<Img> {
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if !have("mkfs.btrfs") {
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eprintln!("SKIP: mkfs.btrfs ausente");
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return None;
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}
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let dir = tempfile::tempdir().unwrap();
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let root = dir.path().join("root");
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std::fs::create_dir_all(root.join("docs/sub")).unwrap();
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std::fs::create_dir_all(root.join("fotos")).unwrap();
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let files = vec![
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("docs/relatorio.dat", data(1, 150_000)),
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("docs/sub/contrato.dat", data(2, 9_000)),
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("fotos/viagem.dat", data(3, 700_000)),
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("fotos/fica.dat", data(4, 30_000)),
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("pequeno.txt", b"conteudo pequeno inline".to_vec()),
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];
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for (p, c) in &files {
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std::fs::write(root.join(p), c).unwrap();
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}
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let path = dir.path().join("b.img");
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std::fs::File::create(&path).unwrap().set_len(128 << 20).unwrap();
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let o = Command::new("mkfs.btrfs").args(["-q", "-f", "--rootdir"]).arg(&root).arg(&path).output().unwrap();
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assert!(o.status.success(), "{}", String::from_utf8_lossy(&o.stderr));
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Some(Img { _dir: dir, path, files })
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}
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#[test]
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fn lists_the_live_tree_with_paths_and_sizes() {
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let Some(i) = build() else { return };
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let src = FileSource::open(&i.path).unwrap();
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let listed = live_paths(&src, 0);
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for (p, c) in &i.files {
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let f = listed.iter().find(|x| x.0 == *p).unwrap_or_else(|| panic!("{p} ausente: {listed:?}"));
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assert_eq!(f.1, c.len() as u64, "{p}");
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assert!(!f.2);
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}
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assert!(listed.iter().any(|x| x.0 == "docs/sub" && x.2));
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}
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// --- manipulação bruta de folhas (independente do módulo) ---
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struct Leaf {
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raw: Vec<u8>,
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}
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impl Leaf {
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fn nritems(&self) -> usize {
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u32::from_le_bytes(self.raw[96..100].try_into().unwrap()) as usize
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}
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fn item(&self, i: usize) -> (u64, u8, u64, usize, usize) {
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let o = 101 + i * 25;
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let r = &self.raw;
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(
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u64::from_le_bytes(r[o..o + 8].try_into().unwrap()),
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r[o + 8],
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u64::from_le_bytes(r[o + 9..o + 17].try_into().unwrap()),
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u32::from_le_bytes(r[o + 17..o + 21].try_into().unwrap()) as usize,
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u32::from_le_bytes(r[o + 21..o + 25].try_into().unwrap()) as usize,
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)
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}
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fn data(&self, i: usize) -> &[u8] {
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let (_, _, _, off, size) = self.item(i);
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&self.raw[101 + off..101 + off + size]
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}
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fn seal(&mut self) {
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let c = crc32c(&self.raw[32..]);
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self.raw[0..4].copy_from_slice(&c.to_le_bytes());
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}
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/// Nova versão da folha sem os itens que `drop` rejeita, num novo endereço lógico.
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fn without(&self, drop: impl Fn(u64, u8) -> bool, new_bytenr: u64) -> Leaf {
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let mut kept: Vec<(usize, Vec<u8>)> = vec![];
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for i in 0..self.nritems() {
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let (obj, ty, _, _, _) = self.item(i);
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if !drop(obj, ty) {
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kept.push((i, self.data(i).to_vec()));
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}
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}
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let mut raw = vec![0u8; self.raw.len()];
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raw[..101].copy_from_slice(&self.raw[..101]);
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raw[48..56].copy_from_slice(&new_bytenr.to_le_bytes());
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let gen = u64::from_le_bytes(raw[80..88].try_into().unwrap()) + 1;
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raw[80..88].copy_from_slice(&gen.to_le_bytes());
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raw[96..100].copy_from_slice(&(kept.len() as u32).to_le_bytes());
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let mut end = raw.len() - 101;
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for (n, (i, d)) in kept.iter().enumerate() {
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let o = 101 + n * 25;
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raw[o..o + 17].copy_from_slice(&self.raw[101 + i * 25..101 + i * 25 + 17]);
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end -= d.len();
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raw[o + 17..o + 21].copy_from_slice(&(end as u32).to_le_bytes());
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raw[o + 21..o + 25].copy_from_slice(&(d.len() as u32).to_le_bytes());
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raw[101 + end..101 + end + d.len()].copy_from_slice(d);
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}
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let mut l = Leaf { raw };
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l.seal();
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l
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}
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}
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fn superblock(img: &[u8]) -> &[u8] {
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&img[0x10000..0x11000]
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}
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/// Mapa lógico -> físico dos chunks de sistema (suficiente para imagens pequenas de um dispositivo).
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fn chunk_map(img: &[u8]) -> Vec<(u64, u64, u64)> {
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let sb = superblock(img);
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let n = u32::from_le_bytes(sb[160..164].try_into().unwrap()) as usize;
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let arr = &sb[0x32B..0x32B + n];
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let mut p = 0;
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let mut out = vec![];
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while p + 17 + 80 <= arr.len() {
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let logical = u64::from_le_bytes(arr[p + 9..p + 17].try_into().unwrap());
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let len = u64::from_le_bytes(arr[p + 17..p + 25].try_into().unwrap());
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let phys = u64::from_le_bytes(arr[p + 17 + 48 + 8..p + 17 + 48 + 16].try_into().unwrap());
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out.push((logical, len, phys));
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let ns = u16::from_le_bytes(arr[p + 17 + 44..p + 17 + 46].try_into().unwrap()) as usize;
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p += 17 + 48 + ns * 32;
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}
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out
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}
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#[test]
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fn deleted_file_survives_in_the_previous_version_of_the_leaf() {
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let Some(i) = build() else { return };
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let mut img = std::fs::read(&i.path).unwrap();
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let sb = superblock(&img).to_vec();
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let nodesize = u32::from_le_bytes(sb[148..152].try_into().unwrap()) as usize;
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let src = FileSource::open(&i.path).unwrap();
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let t = guara_core::fs::btrfs::locate_trees(&src, 0).expect("árvores");
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assert_eq!(t.nodesize as usize, nodesize);
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let fs_leaf = (t.fs_tree as usize, t.fs_tree_logical);
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let root_leaf = (t.root_tree as usize, t.root_tree_logical);
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let ext_leaf = (t.extent_tree as usize, t.extent_tree_logical);
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let to_logical = |phys: usize| -> u64 {
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let c = t.chunks.iter().find(|c| (phys as u64) >= c.2 && (phys as u64) < c.2 + c.1).expect("chunk");
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c.0 + (phys as u64 - c.2)
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};
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let fl = Leaf { raw: img[fs_leaf.0..fs_leaf.0 + nodesize].to_vec() };
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// inode do arquivo apagado
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let victim = "relatorio.dat";
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let mut ino = 0;
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for k in 0..fl.nritems() {
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let (obj, ty, _, _, _) = fl.item(k);
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if ty == 12 {
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let d = fl.data(k);
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let nl = u16::from_le_bytes([d[8], d[9]]) as usize;
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if &d[10..10 + nl] == victim.as_bytes() {
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ino = obj;
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}
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}
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}
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assert!(ino > 256);
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// extent de dados do arquivo (para liberar no extent tree)
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let mut data_bytenr = 0;
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for k in 0..fl.nritems() {
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let (obj, ty, _, _, _) = fl.item(k);
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if obj == ino && ty == 108 {
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data_bytenr = u64::from_le_bytes(fl.data(k)[21..29].try_into().unwrap());
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}
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}
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assert!(data_bytenr > 0);
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// Novo bloco livre para a nova versão: primeiro bloco do metadata sem folha válida e todo zero.
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let free_slot = (0..img.len() / nodesize)
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.map(|n| n * nodesize)
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.find(|&o| o > fs_leaf.0 && img[o..o + nodesize].iter().all(|&x| x == 0) && t.chunks.iter().any(|c| (o as u64) >= c.2 && (o as u64) < c.2 + c.1) && o < fs_leaf.0 + (8 << 20))
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.expect("bloco livre");
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// logical = bytenr da folha antiga + (offset físico - offset físico antigo): mesmo chunk
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let new_bytenr = to_logical(free_slot);
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let newleaf = fl.without(|o, _| o == ino, new_bytenr);
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img[free_slot..free_slot + nodesize].copy_from_slice(&newleaf.raw);
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// Aponta o ROOT_ITEM da árvore 5 para a nova versão (e sobe a geração), na folha da árvore raiz.
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let mut rl = Leaf { raw: img[root_leaf.0..root_leaf.0 + nodesize].to_vec() };
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for k in 0..rl.nritems() {
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let (obj, ty, _, off, _) = rl.item(k);
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if obj == 5 && ty == 132 {
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let at = 101 + off + 176;
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rl.raw[at..at + 8].copy_from_slice(&new_bytenr.to_le_bytes());
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}
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}
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rl.seal();
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img[root_leaf.0..root_leaf.0 + nodesize].copy_from_slice(&rl.raw);
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// Libera o extent de dados no extent tree (em outro endereço da mesma folha).
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let el = Leaf { raw: img[ext_leaf.0..ext_leaf.0 + nodesize].to_vec() };
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let newext = el.without(|o, ty| o == data_bytenr && ty == 168, ext_leaf.1);
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let _ = to_logical;
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img[ext_leaf.0..ext_leaf.0 + nodesize].copy_from_slice(&newext.raw);
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let _ = chunk_map(&img);
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let p2 = i._dir.path().join("deleted.img");
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std::fs::write(&p2, &img).unwrap();
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init();
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let c = scan_path(&p2, &ScanOptions { mode: ScanMode::Deep, ..Default::default() });
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let f = c
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.found
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.iter()
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.find(|f| f.name == victim && f.origin == Origin::Btrfs)
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.unwrap_or_else(|| panic!("não achou: {:?}", c.found.iter().map(|f| (&f.name, f.origin)).collect::<Vec<_>>()));
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assert_eq!(f.size, 150_000);
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assert_eq!(f.dir.as_deref(), Some("/docs"));
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assert!(f.confidence >= Confidence::Medium && f.note.as_deref().unwrap_or("").contains("livres"), "{:?}", f.note);
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let out = i._dir.path().join("out");
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let rep = recover_all(&p2, std::slice::from_ref(f), &out);
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assert!(rep.failed.is_empty(), "{:?}", rep.failed);
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let rp = PathBuf::from(&rep.recovered[0].path);
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let got = std::fs::read(if rp.is_absolute() { rp } else { out.join(rp) }).unwrap();
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assert!(got == i.files[0].1);
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// Os arquivos que continuam existindo não aparecem como apagados.
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assert!(!c.found.iter().any(|f| f.name == "fica.dat" && f.origin == Origin::Btrfs));
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let _ = Path::new("");
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}
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#[test]
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fn lzo_literals_and_a_match() {
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// 20 literais + fim
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let mut s = vec![17 + 20];
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s.extend((0..20u8).map(|i| b'a' + i));
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s.extend_from_slice(&[0x11, 0, 0]);
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assert_eq!(lzo1x_decompress(&s, 4096).unwrap(), (0..20u8).map(|i| b'a' + i).collect::<Vec<_>>());
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// "abcd" + M2 (dist 4, len 4) + fim
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let s = vec![17 + 4, b'a', b'b', b'c', b'd', 0x6C, 0x00, 0x11, 0, 0];
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assert_eq!(lzo1x_decompress(&s, 4096).unwrap(), b"abcdabcd");
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}
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#[test]
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fn packed_extents_decode_zlib_and_zstd() {
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use guara_core::source::MemSource;
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use guara_core::{Packed, PackedCodec};
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use std::io::Write;
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let plain: Vec<u8> = (0..100_000u32).map(|i| (i % 251) as u8).collect();
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// zlib
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let mut e = flate2::write::ZlibEncoder::new(vec![], flate2::Compression::default());
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e.write_all(&plain).unwrap();
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let z = e.finish().unwrap();
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let mut disk = vec![0u8; 4096];
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disk.extend_from_slice(&z);
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let p = Packed { offset: 4096, disk_len: z.len() as u64, ram_len: plain.len() as u64, skip: 1000, len: 5000, codec: PackedCodec::Zlib };
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assert_eq!(p.read(&MemSource(disk)).unwrap(), &plain[1000..6000]);
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// zstd, se o utilitário existir
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if have("zstd") {
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let dir = tempfile::tempdir().unwrap();
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let f = dir.path().join("p.bin");
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std::fs::write(&f, &plain).unwrap();
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assert!(Command::new("zstd").args(["-q", "-f"]).arg(&f).status().unwrap().success());
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let z = std::fs::read(dir.path().join("p.bin.zst")).unwrap();
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let p = Packed { offset: 0, disk_len: z.len() as u64, ram_len: plain.len() as u64, skip: 0, len: plain.len() as u64, codec: PackedCodec::Zstd };
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assert!(p.read(&MemSource(z)).unwrap() == plain);
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}
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}
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