streams: Re-add support for arbitrary metadata for stream notifier functions (#19158)

Support for attaching arbitrary metadata for consumption by stream notifier
functions got broken in #19024 when the previous `zval ptr` got
changed to `zend_fcall_info_cache *fcc`, making the data specific to the
`user_space_stream_notifier`.

Fix this by changing the field to `void *ptr`, avoiding the indirection through
a `zval`, but preserving the ability to store arbitrary data. If necessary to
support different types than `IS_PTR`, extensions can heap-allocate a `zval` to
store within `->ptr` as a minimal change to keep compatibility with PHP 8.4 or
lower.

Author: TimWolla

NEWS

@@ -4,6 +4,7 @@ PHP                                                                        NEWS
 
 - Core:
   . Add clone-with support to the clone() function. (timwolla, edorian)
+  . Fix support for non-userland stream notifiers. (timwolla)
 
 - Curl:
   . Add support for CURLINFO_CONN_ID in curl_getinfo() (thecaliskan)

UPGRADING.INTERNALS

@@ -23,6 +23,11 @@ PHP 8.5 INTERNALS UPGRADE NOTES
     the user side when requiring libphp.so, by using dlmopen with LM_ID_NEWLM
     instead of dlopen.
     RTLD_DEEPBIND is still enabled when the Apache SAPI is in use.
+  . The ptr field of the php_stream_notifier struct is now a void* instead
+    of a zval. If the zval was used to store IS_PTR values only, the
+    extra layer of indirection can be removed. In other cases a zval can
+    be heap-allocated and stored in the pointer as a minimal change to keep
+    compatibility.
 
 - Zend
   . Added zend_safe_assign_to_variable_noref() function to safely assign

ext/standard/streamsfuncs.c

@@ -869,19 +869,17 @@ static void user_space_stream_notifier(php_stream_context *context, int notifyco
 	ZVAL_LONG(&zvs[4], bytes_sofar);
 	ZVAL_LONG(&zvs[5], bytes_max);
 
-	zend_call_known_fcc(context->notifier->fcc, NULL, 6, zvs, NULL);
+	zend_call_known_fcc(context->notifier->ptr, NULL, 6, zvs, NULL);
 	/* Free refcounted string parameter */
 	zval_ptr_dtor_str(&zvs[2]);
 }
 
 static void user_space_stream_notifier_dtor(php_stream_notifier *notifier)
 {
-	ZEND_ASSERT(notifier);
-	ZEND_ASSERT(notifier->fcc);
-	ZEND_ASSERT(notifier->fcc->function_handler);
-	zend_fcc_dtor(notifier->fcc);
-	efree(notifier->fcc);
-	notifier->fcc = NULL;
+	zend_fcall_info_cache *fcc = notifier->ptr;
+	zend_fcc_dtor(fcc);
+	efree(notifier->ptr);
+	notifier->ptr = NULL;
 }
 
 static zend_result parse_context_options(php_stream_context *context, HashTable *options)
@@ -931,7 +929,7 @@ static zend_result parse_context_params(php_stream_context *context, HashTable *
 
 		context->notifier = php_stream_notification_alloc();
 		context->notifier->func = user_space_stream_notifier;
-		context->notifier->fcc = fcc;
+		context->notifier->ptr = fcc;
 		context->notifier->dtor = user_space_stream_notifier_dtor;
 	}
 	if (NULL != (tmp = zend_hash_str_find(params, "options", sizeof("options")-1))) {
@@ -1128,10 +1126,10 @@ PHP_FUNCTION(stream_context_get_params)
 	}
 
 	array_init(return_value);
-	if (context->notifier && context->notifier->fcc) {
-		ZEND_ASSERT(context->notifier->func == user_space_stream_notifier);
+	if (context->notifier && context->notifier->func == user_space_stream_notifier) {
+		zend_fcall_info_cache *fcc = context->notifier->ptr;
 		zval fn;
-		zend_get_callable_zval_from_fcc(context->notifier->fcc, &fn);
+		zend_get_callable_zval_from_fcc(fcc, &fn);
 		add_assoc_zval_ex(return_value, ZEND_STRL("notification"), &fn);
 	}
 	Z_TRY_ADDREF(context->options);

main/streams/php_stream_context.h

@@ -44,7 +44,7 @@ typedef struct _php_stream_notifier php_stream_notifier;
 struct _php_stream_notifier {
 	php_stream_notification_func func;
 	void (*dtor)(php_stream_notifier *notifier);
-	zend_fcall_info_cache *fcc;
+	void *ptr;
 	int mask;
 	size_t progress, progress_max; /* position for progress notification */
 };