Fix incorrect inflateSyncPoint() return value with DFLTCC

DFLTCC does not provide the necessary information to implement
inflateSyncPoint() - Incomplete-Function Status and Incomplete-Function
Length are the fields that provide the relevant information, but
unfortunately it's not enough. If DFLTCC is in use, the current code
checks software decompression state and always returns 0. This
(rightfully) confuses rsync, so fix by returning Z_STREAM_ERROR
instead.

1 files changed, 3 insertions, 0 deletions

diff --git a/inflate.c b/inflate.c
index 96f7443..3d5efbd 100644
--- a/inflate.c
+++ b/inflate.c
@@ -35,6 +35,8 @@
 #  define INFLATE_NEED_UPDATEWINDOW(strm) 1
 /* Invoked at the beginning of inflateMark(). Useful for updating arch-specific pointers and offsets. */
 #  define INFLATE_MARK_HOOK(strm) do {} while (0)
+/* Invoked at the beginning of inflateSyncPoint(). Useful for performing arch-specific state checks. */
+#define INFLATE_SYNC_POINT_HOOK(strm) do {} while (0)
 #endif
 
 /* function prototypes */
@@ -1254,6 +1256,7 @@ int32_t Z_EXPORT PREFIX(inflateSyncPoint)(PREFIX3(stream) *strm) {
 
     if (inflateStateCheck(strm))
         return Z_STREAM_ERROR;
+    INFLATE_SYNC_POINT_HOOK(strm);
     state = (struct inflate_state *)strm->state;
     return state->mode == STORED && state->bits == 0;
 }