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.

diff --git a/arch/s390/README.md b/arch/s390/README.md
index 2ff88df4027812e7906791aaf84ead97601d0adf..641c63a83227fbef4c0aae03633c60b2f6f2233e 100644 (file)
--- a/arch/s390/README.md
+++ b/arch/s390/README.md
@@ -48,6 +48,7 @@ DFLTCC does not support every single zlib-ng feature, in particular:
 * `inflate(Z_BLOCK)` and `inflate(Z_TREES)`
 * `inflateMark()`
 * `inflatePrime()`
+* `inflateSyncPoint()`
 
 When used, these functions will either switch to software, or, in case
 this is not possible, gracefully fail.
@@ -75,8 +76,9 @@ macros.
 parameter block using `DEFLATE_RESET_KEEP_HOOK()` and
 `INFLATE_RESET_KEEP_HOOK()` macros.
 
-`INFLATE_PRIME_HOOK()` and `INFLATE_MARK_HOOK()` macros make the
-unsupported `inflatePrime()` and `inflateMark()` calls fail gracefully.
+`INFLATE_PRIME_HOOK()`, `INFLATE_MARK_HOOK()` and
+`INFLATE_SYNC_POINT_HOOK()` macros make the respective unsupported
+calls gracefully fail.
 
 `DEFLATE_PARAMS_HOOK()` implements switching between hardware and
 software compression mid-stream using `deflateParams()`. Switching

diff --git a/arch/s390/dfltcc_inflate.h b/arch/s390/dfltcc_inflate.h
index b293ebbec40ef7608837374b4a75e99732233ba2..fc8a000f7b9383af15aa7e3cee3b384e563fae7d 100644 (file)
--- a/arch/s390/dfltcc_inflate.h
+++ b/arch/s390/dfltcc_inflate.h
@@ -41,4 +41,9 @@ int Z_INTERNAL dfltcc_inflate_disable(PREFIX3(streamp) strm);
         if (dfltcc_was_inflate_used((strm))) return -(1L << 16); \
     } while (0)
 
+#define INFLATE_SYNC_POINT_HOOK(strm) \
+    do { \
+        if (dfltcc_was_inflate_used((strm))) return Z_STREAM_ERROR; \
+    } while (0)
+
 #endif

diff --git a/inflate.c b/inflate.c
index 96f7443e1cae700b132ad289dd6066bfdbe5ea3a..3d5efbd0dc6ebc0fae5d567520fdce84cf96083b 100644 (file)
--- 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;
 }