100 lines
2.7 KiB
Rust
100 lines
2.7 KiB
Rust
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extern crate flate2;
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extern crate memmem;
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extern crate tar;
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use self::flate2::read::GzDecoder;
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use self::memmem::{Searcher, TwoWaySearcher};
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use self::tar::Archive;
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use std::fs::File;
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use std::io;
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use std::io::{BufReader, Read, Seek, SeekFrom};
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use std::path::Path;
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struct FileSearcher<'a> {
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buf_reader: BufReader<File>,
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searcher: TwoWaySearcher<'a>,
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offs: usize,
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}
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impl<'a> FileSearcher<'a> {
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fn new(path: &'a Path, magic: &'a [u8]) -> io::Result<FileSearcher<'a>> {
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let file = File::open(path)?;
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Ok(FileSearcher {
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buf_reader: BufReader::new(file),
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searcher: TwoWaySearcher::new(magic),
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offs: 0,
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})
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}
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}
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impl<'a> Iterator for FileSearcher<'a> {
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type Item = io::Result<usize>;
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fn next(&mut self) -> Option<io::Result<usize>> {
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let mut buf = [0; 32 * 1024];
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let ret;
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match self.buf_reader.seek(SeekFrom::Start(self.offs as u64)) {
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Ok(_) => {}
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Err(e) => return Some(Err(e))
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}
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loop {
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match self.buf_reader.read(&mut buf[..]) {
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Ok(0) => {
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ret = None;
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break;
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}
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Ok(n) => {
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match self.searcher.search_in(&buf) {
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Some(pos) => {
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self.offs += pos;
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ret = Some(Ok(self.offs));
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self.offs += 1; // one past the match so we can try again if necessary
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break;
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}
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None => self.offs += n
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}
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}
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Err(e) => {
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ret = Some(Err(e));
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break;
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}
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}
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}
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ret
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}
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}
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const GZIP_MAGIC: &[u8] = b"\x1f\x8b\x08";
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pub fn extract_to(src: &Path, dst: &Path) -> io::Result<()> {
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let mut found = false;
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let searcher = FileSearcher::new(src, GZIP_MAGIC)?;
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for result in searcher {
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let offs = result?;
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if extract_at_offset(src, offs, dst).is_ok() {
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trace!("tarball found at offset {} was extracted successfully", offs);
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found = true;
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break;
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}
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}
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if found {
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Ok(())
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} else {
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Err(io::Error::new(io::ErrorKind::Other, "no tarball found inside binary"))
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}
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}
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fn extract_at_offset(src: &Path, offs: usize, dst: &Path) -> io::Result<()> {
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let mut f = File::open(src)?;
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f.seek(SeekFrom::Start(offs as u64))?;
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let gz = GzDecoder::new(f);
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let mut tar = Archive::new(gz);
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tar.unpack(dst)?;
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Ok(())
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}
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