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accessor: don't mess with internal decoder state

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skipping a filename is trivial enough to not abuse internal
decoder methods

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
This commit is contained in:
Wolfgang Bumiller 2020-06-15 10:33:06 +02:00
parent a191c6a76a
commit 1187920fff
1 changed files with 13 additions and 16 deletions
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29
src/accessor/mod.rs
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@ -199,24 +199,20 @@ async fn get_decoder_at_filename<T: ReadAt>(
entry_range: Range<u64>,
path: PathBuf,
) -> io::Result<(DecoderImpl<SeqReadAtAdapter<T>>, u64)> {
let mut decoder = get_decoder(input, entry_range, path).await?;
decoder.path_lengths.push(0);
decoder.read_next_header().await?;
if decoder.current_header.htype != format::PXAR_FILENAME {
io_bail!(
"expected filename entry, got {}",
decoder.current_header,
);
// Read the header, it should be a FILENAME, then skip over it and its length:
let header: format::Header = read_entry_at(&input, entry_range.start).await?;
header.check_header_size()?;
if header.htype != format::PXAR_FILENAME {
io_bail!("expected filename entry, got {:?}", header);
}
if decoder.read_current_item().await? != decoder::ItemResult::Entry {
// impossible, since we checked the header type above for a "proper" error message
io_bail!("unexpected decoder state");
let entry_offset = entry_range.start + header.full_size();
if entry_offset >= entry_range.end {
io_bail!("filename exceeds current file range");
}
let entry_offset = decoder::seq_read_position(&mut decoder.input)
.await
.transpose()?
.ok_or_else(|| io_format_err!("reader provided no offset"))?;
Ok((decoder, entry_offset))
Ok((get_decoder(input, entry_offset..entry_range.end, path).await?, entry_offset))
}
impl<T: Clone + ReadAt> AccessorImpl<T> {
@ -297,6 +293,7 @@ impl<T: Clone + ReadAt> AccessorImpl<T> {
.next()
.await
.ok_or_else(|| io_format_err!("unexpected EOF while following a hardlink"))??;
match entry.kind() {
EntryKind::File { offset: None, .. } => {
io_bail!("failed to follow hardlink, reader provided no offsets");