657 lines
20 KiB
Rust
657 lines
20 KiB
Rust
//! *pxar* format decoder.
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//!
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//! This module contain the code to decode *pxar* archive files.
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use failure::*;
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use endian_trait::Endian;
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use super::format_definition::*;
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use crate::tools;
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use std::io::{Read, Write, Seek, SeekFrom};
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use std::path::{Path, PathBuf};
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use std::os::unix::io::AsRawFd;
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use std::os::unix::io::RawFd;
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use std::os::unix::io::FromRawFd;
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use std::os::unix::ffi::{OsStrExt, OsStringExt};
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use std::ffi::{OsStr, OsString};
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use nix::fcntl::OFlag;
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use nix::sys::stat::Mode;
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use nix::errno::Errno;
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use nix::NixPath;
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pub struct CaDirectoryEntry {
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start: u64,
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end: u64,
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pub filename: OsString,
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pub entry: CaFormatEntry,
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}
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// This one needs Read+Seek (we may want one without Seek?)
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pub struct PxarDecoder<'a, R: Read + Seek> {
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reader: &'a mut R,
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root_start: u64,
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root_end: u64,
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}
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const HEADER_SIZE: u64 = std::mem::size_of::<CaFormatHeader>() as u64;
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impl <'a, R: Read + Seek> PxarDecoder<'a, R> {
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pub fn new(reader: &'a mut R) -> Result<Self, Error> {
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let root_end = reader.seek(SeekFrom::End(0))?;
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Ok(Self {
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reader: reader,
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root_start: 0,
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root_end: root_end,
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})
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}
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pub fn root(&self) -> CaDirectoryEntry {
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CaDirectoryEntry {
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start: self.root_start,
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end: self.root_end,
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filename: OsString::new(), // Empty
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entry: CaFormatEntry {
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feature_flags: 0,
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mode: 0,
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flags: 0,
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uid: 0,
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gid: 0,
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mtime: 0,
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}
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}
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}
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fn read_item<T: Endian>(&mut self) -> Result<T, Error> {
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let mut result: T = unsafe { std::mem::uninitialized() };
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let buffer = unsafe { std::slice::from_raw_parts_mut(
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&mut result as *mut T as *mut u8,
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std::mem::size_of::<T>()
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)};
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self.reader.read_exact(buffer)?;
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Ok(result.from_le())
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}
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fn read_symlink(&mut self, size: u64) -> Result<PathBuf, Error> {
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if size < (HEADER_SIZE + 2) {
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bail!("dectected short symlink target.");
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}
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let target_len = size - HEADER_SIZE;
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if target_len > (libc::PATH_MAX as u64) {
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bail!("symlink target too long ({}).", target_len);
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}
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let mut buffer = vec![0u8; target_len as usize];
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self.reader.read_exact(&mut buffer)?;
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let last_byte = buffer.pop().unwrap();
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if last_byte != 0u8 {
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bail!("symlink target not nul terminated.");
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}
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Ok(PathBuf::from(std::ffi::OsString::from_vec(buffer)))
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}
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fn read_filename(&mut self, size: u64) -> Result<OsString, Error> {
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if size < (HEADER_SIZE + 2) {
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bail!("dectected short filename");
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}
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let name_len = size - HEADER_SIZE;
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if name_len > ((libc::FILENAME_MAX as u64) + 1) {
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bail!("filename too long ({}).", name_len);
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}
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let mut buffer = vec![0u8; name_len as usize];
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self.reader.read_exact(&mut buffer)?;
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let last_byte = buffer.pop().unwrap();
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if last_byte != 0u8 {
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bail!("filename entry not nul terminated.");
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}
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if buffer.iter().find(|b| (**b == b'/')).is_some() {
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bail!("found invalid filename with slashes.");
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}
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Ok(std::ffi::OsString::from_vec(buffer))
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}
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pub fn restore<F: Fn(&Path) -> Result<(), Error>>(
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&mut self,
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dir: &CaDirectoryEntry,
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callback: F,
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) -> Result<(), Error> {
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let start = dir.start;
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self.reader.seek(SeekFrom::Start(start))?;
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let base = ".";
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let mut path = PathBuf::from(base);
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let dir = match nix::dir::Dir::open(&path, nix::fcntl::OFlag::O_DIRECTORY, nix::sys::stat::Mode::empty()) {
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Ok(dir) => dir,
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Err(err) => bail!("unable to open base directory - {}", err),
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};
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let restore_dir = "restoretest";
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path.push(restore_dir);
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self.restore_sequential(&mut path, &OsString::from(restore_dir), &dir, &callback)?;
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Ok(())
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}
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fn restore_attributes(&mut self, _entry: &CaFormatEntry) -> Result<CaFormatHeader, Error> {
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loop {
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let head: CaFormatHeader = self.read_item()?;
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match head.htype {
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// fimxe: impl ...
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_ => return Ok(head),
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}
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}
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}
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fn restore_mode(&mut self, entry: &CaFormatEntry, fd: RawFd) -> Result<(), Error> {
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let mode = Mode::from_bits_truncate((entry.mode as u32) & 0o7777);
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nix::sys::stat::fchmod(fd, mode)?;
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Ok(())
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}
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fn restore_mode_at(&mut self, entry: &CaFormatEntry, dirfd: RawFd, filename: &OsStr) -> Result<(), Error> {
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let mode = Mode::from_bits_truncate((entry.mode as u32) & 0o7777);
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// NOTE: we want :FchmodatFlags::NoFollowSymlink, but fchmodat does not support that
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// on linux (see man fchmodat). Fortunately, we can simply avoid calling this on symlinks.
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nix::sys::stat::fchmodat(Some(dirfd), filename, mode, nix::sys::stat::FchmodatFlags::FollowSymlink)?;
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Ok(())
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}
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fn restore_ugid(&mut self, entry: &CaFormatEntry, fd: RawFd) -> Result<(), Error> {
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let uid = entry.uid as u32;
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let gid = entry.gid as u32;
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let res = unsafe { libc::fchown(fd, uid, gid) };
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Errno::result(res)?;
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Ok(())
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}
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fn restore_ugid_at(&mut self, entry: &CaFormatEntry, dirfd: RawFd, filename: &OsStr) -> Result<(), Error> {
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let uid = entry.uid as u32;
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let gid = entry.gid as u32;
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let res = filename.with_nix_path(|cstr| unsafe {
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libc::fchownat(dirfd, cstr.as_ptr(), uid, gid, libc::AT_SYMLINK_NOFOLLOW)
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})?;
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Errno::result(res)?;
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Ok(())
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}
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fn restore_mtime(&mut self, entry: &CaFormatEntry, fd: RawFd) -> Result<(), Error> {
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let times = nsec_to_update_timespec(entry.mtime);
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let res = unsafe { libc::futimens(fd, ×[0]) };
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Errno::result(res)?;
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Ok(())
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}
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fn restore_mtime_at(&mut self, entry: &CaFormatEntry, dirfd: RawFd, filename: &OsStr) -> Result<(), Error> {
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let times = nsec_to_update_timespec(entry.mtime);
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let res = filename.with_nix_path(|cstr| unsafe {
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libc::utimensat(dirfd, cstr.as_ptr(), ×[0], libc::AT_SYMLINK_NOFOLLOW)
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})?;
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Errno::result(res)?;
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Ok(())
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}
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fn restore_device_at(&mut self, entry: &CaFormatEntry, dirfd: RawFd, filename: &OsStr, device: &CaFormatDevice) -> Result<(), Error> {
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let rdev = nix::sys::stat::makedev(device.major, device.minor);
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let mode = ((entry.mode as u32) & libc::S_IFMT) | 0o0600;
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let res = filename.with_nix_path(|cstr| unsafe {
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libc::mknodat(dirfd, cstr.as_ptr(), mode, rdev)
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})?;
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Errno::result(res)?;
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Ok(())
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}
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fn restore_socket_at(&mut self, dirfd: RawFd, filename: &OsStr) -> Result<(), Error> {
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let mode = libc::S_IFSOCK | 0o0600;
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let res = filename.with_nix_path(|cstr| unsafe {
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libc::mknodat(dirfd, cstr.as_ptr(), mode, 0)
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})?;
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Errno::result(res)?;
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Ok(())
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}
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fn restore_fifo_at(&mut self, dirfd: RawFd, filename: &OsStr) -> Result<(), Error> {
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let mode = libc::S_IFIFO | 0o0600;
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let res = filename.with_nix_path(|cstr| unsafe {
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libc::mkfifoat(dirfd, cstr.as_ptr(), mode)
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})?;
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Errno::result(res)?;
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Ok(())
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}
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pub fn restore_sequential<F: Fn(&Path) -> Result<(), Error>>(
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&mut self,
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path: &mut PathBuf, // user for error reporting
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filename: &OsStr, // repeats path last component
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parent: &nix::dir::Dir,
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callback: &F,
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) -> Result<(), Error> {
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let parent_fd = parent.as_raw_fd();
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// read ENTRY first
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let head: CaFormatHeader = self.read_item()?;
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check_ca_header::<CaFormatEntry>(&head, CA_FORMAT_ENTRY)?;
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let entry: CaFormatEntry = self.read_item()?;
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let mode = entry.mode as u32; //fixme: upper 32bits?
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let ifmt = mode & libc::S_IFMT;
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if ifmt == libc::S_IFDIR {
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let dir = match dir_mkdirat(parent_fd, filename) {
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Ok(dir) => dir,
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Err(err) => bail!("unable to open directory {:?} - {}", path, err),
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};
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let mut head = self.restore_attributes(&entry)?;
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while head.htype == CA_FORMAT_FILENAME {
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let name = self.read_filename(head.size)?;
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path.push(&name);
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println!("NAME: {:?}", path);
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self.restore_sequential(path, &name, &dir, callback)?;
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path.pop();
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head = self.read_item()?;
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}
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if head.htype != CA_FORMAT_GOODBYE {
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bail!("got unknown header type inside directory entry {:016x}", head.htype);
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}
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println!("Skip Goodbye");
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if head.size < HEADER_SIZE { bail!("detected short goodbye table"); }
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// self.reader.seek(SeekFrom::Current((head.size - HEADER_SIZE) as i64))?;
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let mut done = 0;
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let skip = (head.size - HEADER_SIZE) as usize;
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let mut skip_buffer = vec![0u8; 64*1024];
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while done < skip {
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let todo = skip - done;
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let n = if todo > skip_buffer.len() { skip_buffer.len() } else { todo };
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let data = &mut skip_buffer[..n];
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self.reader.read_exact(data)?;
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done += n;
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}
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self.restore_mode(&entry, dir.as_raw_fd())?;
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self.restore_mtime(&entry, dir.as_raw_fd())?;
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self.restore_ugid(&entry, dir.as_raw_fd())?;
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return Ok(());
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}
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if ifmt == libc::S_IFLNK {
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// fixme: create symlink
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//fixme: restore permission, acls, xattr, ...
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let head: CaFormatHeader = self.read_item()?;
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match head.htype {
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CA_FORMAT_SYMLINK => {
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let target = self.read_symlink(head.size)?;
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println!("TARGET: {:?}", target);
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if let Err(err) = symlinkat(&target, parent_fd, filename) {
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bail!("create symlink {:?} failed - {}", path, err);
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}
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}
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_ => {
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bail!("got unknown header type inside symlink entry {:016x}", head.htype);
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}
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}
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// self.restore_mode_at(&entry, parent_fd, filename)?; //not supported on symlinks
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self.restore_ugid_at(&entry, parent_fd, filename)?;
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self.restore_mtime_at(&entry, parent_fd, filename)?;
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return Ok(());
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}
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if ifmt == libc::S_IFSOCK {
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self.restore_socket_at(parent_fd, filename)?;
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self.restore_mode_at(&entry, parent_fd, filename)?;
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self.restore_ugid_at(&entry, parent_fd, filename)?;
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self.restore_mtime_at(&entry, parent_fd, filename)?;
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return Ok(());
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}
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if ifmt == libc::S_IFIFO {
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self.restore_fifo_at(parent_fd, filename)?;
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self.restore_mode_at(&entry, parent_fd, filename)?;
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self.restore_ugid_at(&entry, parent_fd, filename)?;
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self.restore_mtime_at(&entry, parent_fd, filename)?;
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return Ok(());
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}
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if (ifmt == libc::S_IFBLK) || (ifmt == libc::S_IFCHR) {
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let head: CaFormatHeader = self.read_item()?;
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match head.htype {
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CA_FORMAT_DEVICE => {
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let device: CaFormatDevice = self.read_item()?;
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self.restore_device_at(&entry, parent_fd, filename, &device)?;
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}
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_ => {
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bail!("got unknown header type inside device entry {:016x}", head.htype);
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}
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}
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self.restore_mode_at(&entry, parent_fd, filename)?;
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self.restore_ugid_at(&entry, parent_fd, filename)?;
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self.restore_mtime_at(&entry, parent_fd, filename)?;
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return Ok(());
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}
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if ifmt == libc::S_IFREG {
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let mut read_buffer: [u8; 64*1024] = unsafe { std::mem::uninitialized() };
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let flags = OFlag::O_CREAT|OFlag::O_WRONLY|OFlag::O_EXCL;
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let open_mode = Mode::from_bits_truncate(0o0600 | mode);
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let mut file = match file_openat(parent_fd, filename, flags, open_mode) {
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Ok(file) => file,
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Err(err) => bail!("open file {:?} failed - {}", path, err),
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};
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let head = self.restore_attributes(&entry)?;
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if head.htype != CA_FORMAT_PAYLOAD {
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bail!("got unknown header type for file entry {:016x}", head.htype);
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}
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if head.size < HEADER_SIZE {
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bail!("detected short payload");
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}
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let need = (head.size - HEADER_SIZE) as usize;
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//self.reader.seek(SeekFrom::Current(need as i64))?;
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let mut done = 0;
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while done < need {
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let todo = need - done;
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let n = if todo > read_buffer.len() { read_buffer.len() } else { todo };
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let data = &mut read_buffer[..n];
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self.reader.read_exact(data)?;
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file.write_all(data)?;
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done += n;
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}
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self.restore_mode(&entry, file.as_raw_fd())?;
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self.restore_mtime(&entry, file.as_raw_fd())?;
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self.restore_ugid(&entry, file.as_raw_fd())?;
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return Ok(());
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}
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Ok(())
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}
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fn read_directory_entry(&mut self, start: u64, end: u64) -> Result<CaDirectoryEntry, Error> {
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self.reader.seek(SeekFrom::Start(start))?;
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let mut buffer = [0u8; HEADER_SIZE as usize];
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self.reader.read_exact(&mut buffer)?;
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let head = tools::map_struct::<CaFormatHeader>(&buffer)?;
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if u64::from_le(head.htype) != CA_FORMAT_FILENAME {
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bail!("wrong filename header type for object [{}..{}]", start, end);
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}
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let name_len = u64::from_le(head.size);
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let entry_start = start + name_len;
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let filename = self.read_filename(name_len)?;
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let head: CaFormatHeader = self.read_item()?;
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check_ca_header::<CaFormatEntry>(&head, CA_FORMAT_ENTRY)?;
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let entry: CaFormatEntry = self.read_item()?;
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Ok(CaDirectoryEntry {
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start: entry_start,
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end: end,
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filename: filename,
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entry: CaFormatEntry {
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feature_flags: u64::from_le(entry.feature_flags),
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mode: u64::from_le(entry.mode),
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flags: u64::from_le(entry.flags),
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uid: u64::from_le(entry.uid),
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gid: u64::from_le(entry.gid),
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mtime: u64::from_le(entry.mtime),
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},
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})
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}
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pub fn list_dir(&mut self, dir: &CaDirectoryEntry) -> Result<Vec<CaDirectoryEntry>, Error> {
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const GOODBYE_ITEM_SIZE: u64 = std::mem::size_of::<CaFormatGoodbyeItem>() as u64;
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let start = dir.start;
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let end = dir.end;
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//println!("list_dir1: {} {}", start, end);
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if (end - start) < (HEADER_SIZE + GOODBYE_ITEM_SIZE) {
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bail!("detected short object [{}..{}]", start, end);
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}
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self.reader.seek(SeekFrom::Start(end - GOODBYE_ITEM_SIZE))?;
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let mut buffer = [0u8; GOODBYE_ITEM_SIZE as usize];
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self.reader.read_exact(&mut buffer)?;
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let item = tools::map_struct::<CaFormatGoodbyeItem>(&buffer)?;
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if u64::from_le(item.hash) != CA_FORMAT_GOODBYE_TAIL_MARKER {
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bail!("missing goodbye tail marker for object [{}..{}]", start, end);
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}
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let goodbye_table_size = u64::from_le(item.size);
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if goodbye_table_size < (HEADER_SIZE + GOODBYE_ITEM_SIZE) {
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bail!("short goodbye table size for object [{}..{}]", start, end);
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}
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let goodbye_inner_size = goodbye_table_size - HEADER_SIZE - GOODBYE_ITEM_SIZE;
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|
if (goodbye_inner_size % GOODBYE_ITEM_SIZE) != 0 {
|
|
bail!("wrong goodbye inner table size for entry [{}..{}]", start, end);
|
|
}
|
|
|
|
let goodbye_start = end - goodbye_table_size;
|
|
|
|
if u64::from_le(item.offset) != (goodbye_start - start) {
|
|
println!("DEBUG: {} {}", u64::from_le(item.offset), goodbye_start - start);
|
|
bail!("wrong offset in goodbye tail marker for entry [{}..{}]", start, end);
|
|
}
|
|
|
|
self.reader.seek(SeekFrom::Start(goodbye_start))?;
|
|
let mut buffer = [0u8; HEADER_SIZE as usize];
|
|
self.reader.read_exact(&mut buffer)?;
|
|
let head = tools::map_struct::<CaFormatHeader>(&buffer)?;
|
|
|
|
if u64::from_le(head.htype) != CA_FORMAT_GOODBYE {
|
|
bail!("wrong goodbye table header type for entry [{}..{}]", start, end);
|
|
}
|
|
|
|
if u64::from_le(head.size) != goodbye_table_size {
|
|
bail!("wrong goodbye table size for entry [{}..{}]", start, end);
|
|
}
|
|
|
|
let mut buffer = [0u8; GOODBYE_ITEM_SIZE as usize];
|
|
|
|
let mut range_list = Vec::new();
|
|
|
|
for i in 0..goodbye_inner_size/GOODBYE_ITEM_SIZE {
|
|
self.reader.read_exact(&mut buffer)?;
|
|
let item = tools::map_struct::<CaFormatGoodbyeItem>(&buffer)?;
|
|
let item_offset = u64::from_le(item.offset);
|
|
if item_offset > (goodbye_start - start) {
|
|
bail!("goodbye entry {} offset out of range [{}..{}] {} {} {}",
|
|
i, start, end, item_offset, goodbye_start, start);
|
|
}
|
|
let item_start = goodbye_start - item_offset;
|
|
let _item_hash = u64::from_le(item.hash);
|
|
let item_end = item_start + u64::from_le(item.size);
|
|
if item_end > goodbye_start {
|
|
bail!("goodbye entry {} end out of range [{}..{}]",
|
|
i, start, end);
|
|
}
|
|
|
|
range_list.push((item_start, item_end));
|
|
}
|
|
|
|
let mut result = vec![];
|
|
|
|
for (item_start, item_end) in range_list {
|
|
let entry = self.read_directory_entry(item_start, item_end)?;
|
|
//println!("ENTRY: {} {} {:?}", item_start, item_end, entry.filename);
|
|
result.push(entry);
|
|
}
|
|
|
|
Ok(result)
|
|
}
|
|
|
|
pub fn print_filenames<W: std::io::Write>(
|
|
&mut self,
|
|
output: &mut W,
|
|
prefix: &mut PathBuf,
|
|
dir: &CaDirectoryEntry,
|
|
) -> Result<(), Error> {
|
|
|
|
let mut list = self.list_dir(dir)?;
|
|
|
|
list.sort_unstable_by(|a, b| a.filename.cmp(&b.filename));
|
|
|
|
for item in &list {
|
|
|
|
prefix.push(item.filename.clone());
|
|
|
|
let mode = item.entry.mode as u32;
|
|
|
|
let ifmt = mode & libc::S_IFMT;
|
|
|
|
let osstr: &OsStr = prefix.as_ref();
|
|
output.write(osstr.as_bytes())?;
|
|
output.write(b"\n")?;
|
|
|
|
if ifmt == libc::S_IFDIR {
|
|
self.print_filenames(output, prefix, item)?;
|
|
} else if ifmt == libc::S_IFREG {
|
|
} else if ifmt == libc::S_IFLNK {
|
|
} else if ifmt == libc::S_IFBLK {
|
|
} else if ifmt == libc::S_IFCHR {
|
|
} else {
|
|
bail!("unknown item mode/type for {:?}", prefix);
|
|
}
|
|
|
|
prefix.pop();
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
fn file_openat(parent: RawFd, filename: &OsStr, flags: OFlag, mode: Mode) -> Result<std::fs::File, Error> {
|
|
|
|
let fd = filename.with_nix_path(|cstr| {
|
|
nix::fcntl::openat(parent, cstr.as_ref(), flags, mode)
|
|
})??;
|
|
|
|
let file = unsafe { std::fs::File::from_raw_fd(fd) };
|
|
|
|
Ok(file)
|
|
}
|
|
|
|
fn dir_mkdirat(parent: RawFd, filename: &OsStr) -> Result<nix::dir::Dir, Error> {
|
|
|
|
// call mkdirat first
|
|
let res = filename.with_nix_path(|cstr| unsafe {
|
|
libc::mkdirat(parent, cstr.as_ptr(), libc::S_IRWXU)
|
|
})?;
|
|
Errno::result(res)?;
|
|
|
|
let dir = nix::dir::Dir::openat(parent, filename, OFlag::O_DIRECTORY, Mode::empty())?;
|
|
|
|
Ok(dir)
|
|
}
|
|
|
|
fn symlinkat(target: &Path, parent: RawFd, linkname: &OsStr) -> Result<(), Error> {
|
|
|
|
target.with_nix_path(|target| {
|
|
linkname.with_nix_path(|linkname| {
|
|
let res = unsafe { libc::symlinkat(target.as_ptr(), parent, linkname.as_ptr()) };
|
|
Errno::result(res)?;
|
|
Ok(())
|
|
})?
|
|
})?
|
|
}
|
|
|
|
fn nsec_to_update_timespec(mtime_nsec: u64) -> [libc::timespec; 2] {
|
|
|
|
// restore mtime
|
|
const UTIME_OMIT: i64 = ((1 << 30) - 2);
|
|
const NANOS_PER_SEC: i64 = 1_000_000_000;
|
|
|
|
let sec = (mtime_nsec as i64) / NANOS_PER_SEC;
|
|
let nsec = (mtime_nsec as i64) % NANOS_PER_SEC;
|
|
|
|
let times: [libc::timespec; 2] = [
|
|
libc::timespec { tv_sec: 0, tv_nsec: UTIME_OMIT },
|
|
libc::timespec { tv_sec: sec, tv_nsec: nsec },
|
|
];
|
|
|
|
times
|
|
}
|