- Turns out the external entity loader is not a per-thread global but a true

global. Changed code accordingly; however, applications that embed PHP and
  also use libxml2 may be affected negatively.

ext/libxml/libxml.c

@@ -55,6 +55,7 @@
 /* a true global for initialization */
 static int _php_libxml_initialized = 0;
 static int _php_libxml_per_request_initialization = 1;
+static xmlExternalEntityLoader _php_libxml_default_entity_loader;
 
 typedef struct _php_libxml_func_handler {
 	php_libxml_export_node export_func;
@@ -268,7 +269,6 @@ static PHP_GINIT_FUNCTION(libxml)
 	libxml_globals->stream_context = NULL;
 	libxml_globals->error_buffer.c = NULL;
 	libxml_globals->error_list = NULL;
-	libxml_globals->defaultEntityLoader = NULL;
 	libxml_globals->entity_loader.fci.size = 0;
 }
 
@@ -549,6 +549,131 @@ static void php_libxml_internal_error_handler(int error_type, void *ctx, const c
 	}
 }
 
+static xmlParserInputPtr _php_libxml_external_entity_loader(const char *URL,
+		const char *ID, xmlParserCtxtPtr context)
+{
+    xmlParserInputPtr	ret			= NULL;
+    const char			*resource	= NULL;
+	zval				*public		= NULL,
+						*system		= NULL,
+						*ctxzv		= NULL,
+						**params[]	= {&public, &system, &ctxzv},
+						*retval_ptr	= NULL;
+	int					retval;
+	zend_fcall_info		*fci;
+	TSRMLS_FETCH();
+
+	fci = &LIBXML(entity_loader).fci;
+	
+	if (fci->size == 0) {
+		/* no custom user-land callback set up; delegate to original loader */
+		return _php_libxml_default_entity_loader(URL, ID, context);
+	}
+
+	ALLOC_INIT_ZVAL(public);
+	if (ID != NULL) {
+		ZVAL_STRING(public, ID, 1);
+	}
+	ALLOC_INIT_ZVAL(system);
+	if (URL != NULL) {
+		ZVAL_STRING(system, URL, 1);
+	}
+	MAKE_STD_ZVAL(ctxzv);
+	array_init_size(ctxzv, 4);
+
+#define ADD_NULL_OR_STRING_KEY(memb) \
+	if (context->memb == NULL) { \
+		add_assoc_null_ex(ctxzv, #memb, sizeof(#memb)); \
+	} else { \
+		add_assoc_string_ex(ctxzv, #memb, sizeof(#memb), \
+				(char *)context->memb, 1); \
+	}
+	
+	ADD_NULL_OR_STRING_KEY(directory)
+	ADD_NULL_OR_STRING_KEY(intSubName)
+	ADD_NULL_OR_STRING_KEY(extSubURI)
+	ADD_NULL_OR_STRING_KEY(extSubSystem)
+	
+#undef ADD_NULL_OR_STRING_KEY
+	
+	fci->retval_ptr_ptr	= &retval_ptr;
+	fci->params			= params;
+	fci->param_count	= sizeof(params)/sizeof(*params);
+	fci->no_separation	= 1;
+	
+	retval = zend_call_function(fci, &LIBXML(entity_loader).fcc TSRMLS_CC);
+	if (retval != SUCCESS || fci->retval_ptr_ptr == NULL) {
+		php_libxml_ctx_error(context,
+				"Call to user entity loader callback '%s' has failed",
+				fci->function_name);
+	} else {
+		retval_ptr = *fci->retval_ptr_ptr;
+		if (retval_ptr == NULL) {
+			php_libxml_ctx_error(context,
+					"Call to user entity loader callback '%s' has failed; "
+					"probably it has thrown an exception",
+					fci->function_name);
+		} else if (Z_TYPE_P(retval_ptr) == IS_STRING) {
+is_string:
+			resource = Z_STRVAL_P(retval_ptr);
+		} else if (Z_TYPE_P(retval_ptr) == IS_RESOURCE) {
+			php_stream *stream;
+			php_stream_from_zval_no_verify(stream, &retval_ptr);
+			if (stream == NULL) {
+				php_libxml_ctx_error(context,
+						"The user entity loader callback '%s' has returned a "
+						"resource, but it is not a stream",
+						fci->function_name);
+			} else {
+				/* TODO: allow storing the encoding in the stream context? */
+				xmlCharEncoding enc = XML_CHAR_ENCODING_NONE;
+				xmlParserInputBufferPtr pib = xmlAllocParserInputBuffer(enc);
+				if (pib == NULL) {
+					php_libxml_ctx_error(context, "Could not allocate parser "
+							"input buffer");
+				} else {
+					/* make stream not being closed when the zval is freed */
+					zend_list_addref(stream->rsrc_id);
+					pib->context = stream;
+					pib->readcallback = php_libxml_streams_IO_read;
+					pib->closecallback = php_libxml_streams_IO_close;
+					
+					ret = xmlNewIOInputStream(context, pib, enc);
+					if (ret == NULL) {
+						xmlFreeParserInputBuffer(pib);
+					}
+				}
+			}
+		} else if (Z_TYPE_P(retval_ptr) != IS_NULL) {
+			/* retval not string nor resource nor null; convert to string */
+			SEPARATE_ZVAL(&retval_ptr);
+      		convert_to_string(retval_ptr);
+			goto is_string;
+		} /* else is null; don't try anything */
+	}
+
+	if (ret == NULL) {
+		if (resource == NULL) {
+			if (ID == NULL) {
+				ID = "NULL";
+			}
+			php_libxml_ctx_error(context,
+					"Failed to load external entity \"%s\"\n", ID);
+		} else {
+			/* we got the resource in the form of a string; open it */
+			ret = xmlNewInputFromFile(context, resource);
+		}
+	}
+
+	zval_ptr_dtor(&public);
+	zval_ptr_dtor(&system);
+	zval_ptr_dtor(&ctxzv);
+	if (retval_ptr != NULL) {
+		zval_ptr_dtor(&retval_ptr);
+	}
+    return ret;
+}
+
 PHP_LIBXML_API void php_libxml_ctx_error(void *ctx, const char *msg, ...)
 {
 	va_list args;
@@ -586,6 +711,9 @@ PHP_LIBXML_API void php_libxml_initialize(void)
 	if (!_php_libxml_initialized) {
 		/* we should be the only one's to ever init!! */
 		xmlInitParser();
+		
+		_php_libxml_default_entity_loader = xmlGetExternalEntityLoader();
+		xmlSetExternalEntityLoader(_php_libxml_external_entity_loader);
 
 		zend_hash_init(&php_libxml_exports, 0, NULL, NULL, 1);
 
@@ -926,126 +1054,6 @@ static PHP_FUNCTION(libxml_disable_entity_loader)
 }
 /* }}} */
 
-static xmlParserInputPtr _php_libxml_user_entity_loader(const char *URL,
-		const char *ID, xmlParserCtxtPtr context)
-{
-    xmlParserInputPtr	ret			= NULL;
-    const char			*resource	= NULL;
-	zval				*public		= NULL,
-						*system		= NULL,
-						*ctxzv		= NULL,
-						**params[]	= {&public, &system, &ctxzv},
-						*retval_ptr	= NULL;
-	int					retval;
-	zend_fcall_info		*fci;
-	TSRMLS_FETCH();
-
-	fci = &LIBXML(entity_loader).fci;
-
-	ALLOC_INIT_ZVAL(public);
-	if (ID != NULL) {
-		ZVAL_STRING(public, ID, 1);
-	}
-	ALLOC_INIT_ZVAL(system);
-	if (URL != NULL) {
-		ZVAL_STRING(system, URL, 1);
-	}
-	MAKE_STD_ZVAL(ctxzv);
-	array_init_size(ctxzv, 4);
-
-#define ADD_NULL_OR_STRING_KEY(memb) \
-	if (context->memb == NULL) { \
-		add_assoc_null_ex(ctxzv, #memb, sizeof(#memb)); \
-	} else { \
-		add_assoc_string_ex(ctxzv, #memb, sizeof(#memb), \
-				(char *)context->memb, 1); \
-	}
-	
-	ADD_NULL_OR_STRING_KEY(directory)
-	ADD_NULL_OR_STRING_KEY(intSubName)
-	ADD_NULL_OR_STRING_KEY(extSubURI)
-	ADD_NULL_OR_STRING_KEY(extSubSystem)
-	
-#undef ADD_NULL_OR_STRING_KEY
-	
-	fci->retval_ptr_ptr	= &retval_ptr;
-	fci->params			= params;
-	fci->param_count	= sizeof(params)/sizeof(*params);
-	fci->no_separation	= 1;
-	
-	retval = zend_call_function(fci, &LIBXML(entity_loader).fcc TSRMLS_CC);
-	if (retval != SUCCESS || fci->retval_ptr_ptr == NULL) {
-		php_libxml_ctx_error(context,
-				"Call to user entity loader callback '%s' has failed",
-				fci->function_name);
-	} else {
-		retval_ptr = *fci->retval_ptr_ptr;
-		if (retval_ptr == NULL) {
-			php_libxml_ctx_error(context,
-					"Call to user entity loader callback '%s' has failed; "
-					"probably it has thrown an exception",
-					fci->function_name);
-		} else if (Z_TYPE_P(retval_ptr) == IS_STRING) {
-is_string:
-			resource = Z_STRVAL_P(retval_ptr);
-		} else if (Z_TYPE_P(retval_ptr) == IS_RESOURCE) {
-			php_stream *stream;
-			php_stream_from_zval_no_verify(stream, &retval_ptr);
-			if (stream == NULL) {
-				php_libxml_ctx_error(context,
-						"The user entity loader callback '%s' has returned a "
-						"resource, but it is not a stream",
-						fci->function_name);
-			} else {
-				/* TODO: allow storing the encoding in the stream context? */
-				xmlCharEncoding enc = XML_CHAR_ENCODING_NONE;
-				xmlParserInputBufferPtr pib = xmlAllocParserInputBuffer(enc);
-				if (pib == NULL) {
-					php_libxml_ctx_error(context, "Could not allocate parser "
-							"input buffer");
-				} else {
-					/* make stream not being closed when the zval is freed */
-					zend_list_addref(stream->rsrc_id);
-					pib->context = stream;
-					pib->readcallback = php_libxml_streams_IO_read;
-					pib->closecallback = php_libxml_streams_IO_close;
-					
-					ret = xmlNewIOInputStream(context, pib, enc);
-					if (ret == NULL) {
-						xmlFreeParserInputBuffer(pib);
-					}
-				}
-			}
-		} else if (Z_TYPE_P(retval_ptr) != IS_NULL) {
-			/* retval not string nor resource nor null; convert to string */
-			SEPARATE_ZVAL(&retval_ptr);
-      		convert_to_string(retval_ptr);
-			goto is_string;
-		} /* else is null; don't try anything */
-	}
-
-	if (ret == NULL) {
-		if (resource == NULL) {
-			if (ID == NULL) {
-				ID = "NULL";
-			}
-			php_libxml_ctx_error(context,
-					"Failed to load external entity \"%s\"\n", ID);
-		} else {
-			/* we got the resource in the form of a string; open it */
-			ret = xmlNewInputFromFile(context, resource);
-		}
-	}
-
-	zval_ptr_dtor(&public);
-	zval_ptr_dtor(&system);
-	zval_ptr_dtor(&ctxzv);
-	if (retval_ptr != NULL) {
-		zval_ptr_dtor(&retval_ptr);
-	}
-    return ret;
-}
-
 /* {{{ proto void libxml_set_external_entity_loader(callback resolver_function) 
    Changes the default external entity loader */
 static PHP_FUNCTION(libxml_set_external_entity_loader)
@@ -1057,21 +1065,15 @@ static PHP_FUNCTION(libxml_set_external_entity_loader)
 		return;
 	}
 	
+	_php_libxml_destroy_fci(&LIBXML(entity_loader).fci);
+	
 	if (fci.size > 0) { /* argument not null */
-		/* save for later invocations with NULL */
-		if (LIBXML(defaultEntityLoader) == NULL) {
-			LIBXML(defaultEntityLoader) = xmlGetExternalEntityLoader();
-		}
-		_php_libxml_destroy_fci(&LIBXML(entity_loader).fci);
 		LIBXML(entity_loader).fci = fci;
 		Z_ADDREF_P(fci.function_name);
 		if (fci.object_ptr != NULL) {
 			Z_ADDREF_P(fci.object_ptr);
 		}
 		LIBXML(entity_loader).fcc = fcc;
-		xmlSetExternalEntityLoader(_php_libxml_user_entity_loader);
-	} else {
-		xmlSetExternalEntityLoader(LIBXML(defaultEntityLoader));
 	}
 	
 	RETURN_TRUE;

ext/libxml/php_libxml.h

@@ -43,7 +43,6 @@ ZEND_BEGIN_MODULE_GLOBALS(libxml)
 	zval *stream_context;
 	smart_str error_buffer;
 	zend_llist *error_list;
-	xmlExternalEntityLoader defaultEntityLoader; /* saved here to allow it restored */
 	struct _php_libxml_entity_resolver {
 		zend_fcall_info			fci;
 		zend_fcall_info_cache	fcc;