Improve ZBLOCK handling with zlib < 1.2.4

The original commit for this issue (62b1293) assumed Z_BLOCK was
only defined in < 1.2.4. However, this flush type *is* defined but
is only unavailable for use with deflate().

This new commit correctly checks the ZLIB_VERNUM constant to
determine if Z_BLOCK flush is available for the current deflate()
operation and triggers an appropriate error as needed.

New ZLIB_VERSION and ZLIB_VERNUM constants are also exposed in
userland to allow testing this behavior in environments running
zlib < 1.2.4 (ZLIB_VERNUM check is needed).

Author: rdlowrey

ext/zlib/tests/deflate_add_basic.phpt

@@ -43,8 +43,8 @@ $flushTypes = [
     'ZLIB_NO_FLUSH' => ZLIB_NO_FLUSH,
 ];
 
-/* Z_BLOCK is only defined when built against zlib > 1.2.3 */
-if (defined(ZLIB_BLOCK)) {
+/* Z_BLOCK is only available for deflate when built against zlib >= 1.2.4 */
+if (ZLIB_VERNUM >= 0x1240) {
     $flushTypes['ZLIB_BLOCK'] = ZLIB_BLOCK;
 }
 

ext/zlib/tests/deflate_add_block_v123.phpt

@@ -0,0 +1,24 @@
+--TEST--
+Test deflate_add() errors with ZLIB_BLOCK in zlib < 1.2.4
+--SKIPIF--
+<?php 
+if (!extension_loaded("zlib")) {
+    print "skip - ZLIB extension not loaded";
+}
+if (ZLIB_VERNUM >= 0x1240) {
+    print "skip - ZLIB < 1.2.4 required for test";
+}
+?>
+--FILE--
+<?php
+
+$resource = deflate_init(ZLIB_ENCODING_GZIP);
+var_dump(deflate_add($resource, "aaaaaaaaaaaaaaaaaaaaaa", ZLIB_BLOCK));
+
+?>
+===DONE===
+--EXPECTF--
+
+Warning: deflate_add(): zlib >= 1.2.4 required for BLOCK deflate; current version: %s in %s on line %d
+bool(false)
+===DONE===

ext/zlib/tests/inflate_add_basic.phpt

@@ -40,13 +40,9 @@ $flushTypes = [
     'ZLIB_PARTIAL_FLUSH' => ZLIB_PARTIAL_FLUSH,
     'ZLIB_FULL_FLUSH' => ZLIB_FULL_FLUSH,
     'ZLIB_NO_FLUSH' => ZLIB_NO_FLUSH,
+    'ZLIB_BLOCK' => ZLIB_BLOCK,
 ];
 
-/* Z_BLOCK is only defined when built against zlib > 1.2.3 */
-if (defined(ZLIB_BLOCK)) {
-    $flushTypes['ZLIB_BLOCK'] = ZLIB_BLOCK;
-}
-
 $uncompressed = "";
 for ($i=0;$i<(32768*2);$i++) {
     $uncompressed .= chr(rand(48,125));

ext/zlib/zlib.c

@@ -46,13 +46,6 @@
 #undef gzseek
 #undef gztell
 
-/* Z_BLOCK was added in zlib 1.2.4 and stable distros (RHEL6, at least) still
- * package zlib 1.2.3
- */
-#ifdef Z_BLOCK
-#define HAVE_Z_BLOCK 1
-#endif
-
 int le_deflate;
 int le_inflate;
 
@@ -821,9 +814,7 @@ PHP_FUNCTION(inflate_add)
 		case Z_PARTIAL_FLUSH:
 		case Z_SYNC_FLUSH:
 		case Z_FULL_FLUSH:
-#ifdef HAVE_Z_BLOCK
 		case Z_BLOCK:
-#endif
 		case Z_FINISH:
 			break;
 
@@ -965,13 +956,16 @@ PHP_FUNCTION(deflate_add)
 	}
 
 	switch (flush_type) {
+		case Z_BLOCK:
+#if ZLIB_VERNUM < 0x1240L
+			php_error_docref(NULL, E_WARNING,
+				"zlib >= 1.2.4 required for BLOCK deflate; current version: %s", ZLIB_VERSION);
+			RETURN_FALSE;
+#endif
 		case Z_NO_FLUSH:
 		case Z_PARTIAL_FLUSH:
 		case Z_SYNC_FLUSH:
 		case Z_FULL_FLUSH:
-#ifdef HAVE_Z_BLOCK
-		case Z_BLOCK:
-#endif
 		case Z_FINISH:
 			break;
 
@@ -1279,10 +1273,12 @@ static PHP_MINIT_FUNCTION(zlib)
 	REGISTER_LONG_CONSTANT("ZLIB_PARTIAL_FLUSH", Z_PARTIAL_FLUSH, CONST_CS|CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("ZLIB_SYNC_FLUSH", Z_SYNC_FLUSH, CONST_CS|CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("ZLIB_FULL_FLUSH", Z_FULL_FLUSH, CONST_CS|CONST_PERSISTENT);
-#ifdef HAVE_Z_BLOCK
 	REGISTER_LONG_CONSTANT("ZLIB_BLOCK", Z_BLOCK, CONST_CS|CONST_PERSISTENT);
-#endif
 	REGISTER_LONG_CONSTANT("ZLIB_FINISH", Z_FINISH, CONST_CS|CONST_PERSISTENT);
+
+	REGISTER_STRING_CONSTANT("ZLIB_VERSION", ZLIB_VERSION, CONST_CS|CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("ZLIB_VERNUM", ZLIB_VERNUM, CONST_CS|CONST_PERSISTENT);
+
 	REGISTER_INI_ENTRIES();
 	return SUCCESS;
 }