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Work-around for hardlinks unpacking #5

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Work-around for hardlinks unpacking #5

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38 changes: 19 additions & 19 deletions src/Codec/Archive/Unpack.hs
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Original file line number Diff line number Diff line change
Expand Up @@ -96,28 +96,28 @@ unpackEntriesFp a fp = do
case res of
Nothing -> pure ()
Just x -> do
preFile <- liftIO $ archiveEntryPathname x
file <- liftIO $ peekCString preFile
let file' = fp </> file
liftIO $ withCString file' $ \fileC ->
archiveEntrySetPathname x fileC
ft <- liftIO $ archiveEntryFiletype x
case ft of
Just{} -> do
ignore $ archiveReadExtract a x archiveExtractTime
liftIO $ archiveEntrySetPathname x preFile
Nothing -> do
preHardlink <- liftIO $ archiveEntryHardlink x
hardlink <- liftIO $ peekCString preHardlink
let hardlink' = fp </> hardlink
liftIO $ withCString hardlink' $ \hl ->
archiveEntrySetHardlink x hl
ignore $ archiveReadExtract a x archiveExtractTime
liftIO $ archiveEntrySetPathname x preFile
liftIO $ archiveEntrySetHardlink x preHardlink
ignore . withPrefix fp x $ archiveReadExtract a x archiveExtractTime
ignore $ archiveReadDataSkip a
unpackEntriesFp a fp

-- TODO: work with libarchive to get rid of this unsafe hack
-- See https://github.com/libarchive/libarchive/issues/1203
withPrefix :: FilePath -> ArchiveEntryPtr -> IO a -> IO a
withPrefix fp x inner = do
file0 <- peekCString =<< archiveEntryPathname x
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@vmchale vmchale Dec 5, 2019

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Doesn't this mean the pointer to the original archive entry pathname is forgotten? Thus, the original pathname will never be freed.

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@ony ony Dec 5, 2019

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Declaration is const char * archive_entry_pathname(struct archive_entry *a). Thus ownership for returned pointer is not transferred to caller as in char *strdup(const char*). It still owned by archive_entry structure.

You can find similar code in readEntry:

Entry
        <$> (peekCString =<< archiveEntryPathname entry)
        <*> readContents a entry
        -- ...

withCString (fp </> file0) $ archiveEntrySetPathname x
ft <- archiveEntryFiletype x
result <- case ft of
Just{} -> inner
Nothing -> do
target0 <- peekCString =<< archiveEntryHardlink x
withCString (fp </> target0) $ archiveEntrySetHardlink x
result <- inner
withCString target0 $ archiveEntrySetHardlink x
return result
withCString file0 $ archiveEntrySetPathname x
return result

readBS :: Ptr Archive -> Int -> IO BS.ByteString
readBS a sz =
allocaBytes sz $ \buff ->
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