lib-compression: ostream-zlib - Fix sending partial gz header to parent ostream

This practically wouldn't happen.

diff --git a/src/lib-compression/ostream-zlib.c b/src/lib-compression/ostream-zlib.c
index 116d063e6c58e9166f2c5223991a7ae5a5e76f28..b93895d79b06349cd4e9ff82eb819f24fc7d8357 100644 (file)
--- a/src/lib-compression/ostream-zlib.c
+++ b/src/lib-compression/ostream-zlib.c
@@ -19,11 +19,11 @@ struct zlib_ostream {
        unsigned char gz_header[10];
        unsigned char outbuf[CHUNK_SIZE];
        unsigned int outbuf_offset, outbuf_used;
+       unsigned int header_bytes_left;
 
        uint32_t crc, bytes32;
 
        bool gz:1;
-       bool header_sent:1;
        bool flushed:1;
 };
 
@@ -57,16 +57,21 @@ static void o_stream_zlib_close(struct iostream_private *stream,
 
 static int o_stream_zlib_send_gz_header(struct zlib_ostream *zstream)
 {
+       size_t header_send_offset =
+               sizeof(zstream->gz_header) - zstream->header_bytes_left;
        ssize_t ret;
 
-       ret = o_stream_send(zstream->ostream.parent, zstream->gz_header,
-                           sizeof(zstream->gz_header));
-       if ((size_t)ret != sizeof(zstream->gz_header)) {
+       i_assert(zstream->header_bytes_left <= sizeof(zstream->gz_header));
+       ret = o_stream_send(zstream->ostream.parent,
+                           zstream->gz_header + header_send_offset,
+                           zstream->header_bytes_left);
+       if (ret < 0) {
                o_stream_copy_error_from_parent(&zstream->ostream);
                return -1;
        }
-       zstream->header_sent = TRUE;
-       return 0;
+       i_assert(ret <= zstream->header_bytes_left);
+       zstream->header_bytes_left -= ret;
+       return zstream->header_bytes_left == 0 ? 1 : 0;
 }
 
 static int o_stream_zlib_lsb_uint32(struct ostream *output, uint32_t num)
@@ -135,8 +140,8 @@ o_stream_zlib_send_chunk(struct zlib_ostream *zstream,
        flush = zstream->ostream.corked || zstream->gz ?
                Z_NO_FLUSH : Z_SYNC_FLUSH;
 
-       if (!zstream->header_sent) {
-               if (o_stream_zlib_send_gz_header(zstream) < 0)
+       if (zstream->header_bytes_left > 0) {
+               if ((ret = o_stream_zlib_send_gz_header(zstream)) <= 0)
                        return -1;
        }
 
@@ -199,9 +204,9 @@ o_stream_zlib_send_flush(struct zlib_ostream *zstream, bool final)
 
        if ((ret = o_stream_flush_parent_if_needed(&zstream->ostream)) <= 0)
                return ret;
-       if (!zstream->header_sent) {
-               if (o_stream_zlib_send_gz_header(zstream) < 0)
-                       return -1;
+       if (zstream->header_bytes_left > 0) {
+               if ((ret = o_stream_zlib_send_gz_header(zstream)) <= 0)
+                       return ret;
        }
 
        if ((ret = o_stream_zlib_send_outbuf(zstream)) <= 0)
@@ -351,8 +356,8 @@ o_stream_create_zlib(struct ostream *output, int level, bool gz)
        zstream->ostream.iostream.close = o_stream_zlib_close;
        zstream->crc = 0;
        zstream->gz = gz;
-       if (!gz)
-               zstream->header_sent = TRUE;
+       if (gz)
+               zstream->header_bytes_left = sizeof(zstream->gz_header);
 
        o_stream_zlib_init_gz_header(zstream, level, strategy);
        ret = deflateInit2(&zstream->zs, level, Z_DEFLATED, -15, 8, strategy);