istream-zlib: Don't overwrite parent istream's error on gz header/trailer read errors.

diff --git a/src/lib-compression/istream-zlib.c b/src/lib-compression/istream-zlib.c
index a37361ce57f83f709ecf1754aad9d65e916eca2e..463856c57c3110f232814afc9f66bce27558a543 100644 (file)
--- a/src/lib-compression/istream-zlib.c
+++ b/src/lib-compression/istream-zlib.c
@@ -75,7 +75,8 @@ static int i_stream_zlib_read_header(struct istream_private *stream)
        ret = i_stream_read_data(stream->parent, &data, &size,
                                 zstream->prev_size);
        if (size == zstream->prev_size) {
-               if (ret == -1) {
+               stream->istream.stream_errno = stream->parent->stream_errno;
+               if (ret == -1 && stream->istream.stream_errno == 0) {
                        zlib_read_error(zstream, "missing gz header");
                        stream->istream.stream_errno = EINVAL;
                }
@@ -141,7 +142,8 @@ static int i_stream_zlib_read_trailer(struct zlib_istream *zstream)
        ret = i_stream_read_data(stream->parent, &data, &size,
                                 GZ_TRAILER_SIZE-1);
        if (size == zstream->prev_size) {
-               if (ret == -1) {
+               stream->istream.stream_errno = stream->parent->stream_errno;
+               if (ret == -1 && stream->istream.stream_errno == 0) {
                        zlib_read_error(zstream, "missing gz trailer");
                        stream->istream.stream_errno = EINVAL;
                }