Merge pull request #2687 from dmcgowan/fix-pigz-panic

Fix panic when bufio Reader called in 2 goroutines

archive/compression/compression.go

@@ -92,6 +92,36 @@ func (w *writeCloserWrapper) Close() error {
 	return nil
 }
 
+type bufferedReader struct {
+	buf *bufio.Reader
+}
+
+func newBufferedReader(r io.Reader) *bufferedReader {
+	buf := bufioReader32KPool.Get().(*bufio.Reader)
+	buf.Reset(r)
+	return &bufferedReader{buf}
+}
+
+func (r *bufferedReader) Read(p []byte) (n int, err error) {
+	if r.buf == nil {
+		return 0, io.EOF
+	}
+	n, err = r.buf.Read(p)
+	if err == io.EOF {
+		r.buf.Reset(nil)
+		bufioReader32KPool.Put(r.buf)
+		r.buf = nil
+	}
+	return
+}
+
+func (r *bufferedReader) Peek(n int) ([]byte, error) {
+	if r.buf == nil {
+		return nil, io.EOF
+	}
+	return r.buf.Peek(n)
+}
+
 // DetectCompression detects the compression algorithm of the source.
 func DetectCompression(source []byte) Compression {
 	for compression, m := range map[Compression][]byte{
@@ -110,8 +140,7 @@ func DetectCompression(source []byte) Compression {
 
 // DecompressStream decompresses the archive and returns a ReaderCloser with the decompressed archive.
 func DecompressStream(archive io.Reader) (DecompressReadCloser, error) {
-	buf := bufioReader32KPool.Get().(*bufio.Reader)
+	buf := newBufferedReader(archive)
-	buf.Reset(archive)
 	bs, err := buf.Peek(10)
 	if err != nil && err != io.EOF {
 		// Note: we'll ignore any io.EOF error because there are some odd
@@ -123,15 +152,12 @@ func DecompressStream(archive io.Reader) (DecompressReadCloser, error) {
 		return nil, err
 	}
 
-	closer := func() error {
-		buf.Reset(nil)
-		bufioReader32KPool.Put(buf)
-		return nil
-	}
 	switch compression := DetectCompression(bs); compression {
 	case Uncompressed:
-		readBufWrapper := &readCloserWrapper{buf, compression, closer}
+		return &readCloserWrapper{
-		return readBufWrapper, nil
+			Reader:      buf,
+			compression: compression,
+		}, nil
 	case Gzip:
 		ctx, cancel := context.WithCancel(context.Background())
 		gzReader, err := gzipDecompress(ctx, buf)
@@ -140,12 +166,15 @@ func DecompressStream(archive io.Reader) (DecompressReadCloser, error) {
 			return nil, err
 		}
 
-		readBufWrapper := &readCloserWrapper{gzReader, compression, func() error {
+		return &readCloserWrapper{
-			cancel()
+			Reader:      gzReader,
-			return closer()
+			compression: compression,
-		}}
+			closer: func() error {
+				cancel()
+				return gzReader.Close()
+			},
+		}, nil
 
-		return readBufWrapper, nil
 	default:
 		return nil, fmt.Errorf("unsupported compression format %s", (&compression).Extension())
 	}