Include internal functions in the observer API

There are two main motivations to this:
a) The logic for handling internal and userland observation can be unified.
b) Unwinding of observed functions on a bailout does notably not include observers. Even if users of observers were to ensure such handling themselves, it would be impossible to retain the relative ordering - either the user has to unwind all internal observed frames before the automatic unwinding (zend_observer_fcall_end_all) or afterwards, but not properly interleaved.

Signed-off-by: Bob Weinand <bobwei9@hotmail.com>

Author: bwoebi

UPGRADING.INTERNALS

@@ -51,6 +51,7 @@ PHP 8.2 INTERNALS UPGRADE NOTES
   are deprecated (see main UPGRADING notes). To suppress the notice, e.g. to
   avoid duplicates when processing the same value multiple times, pass or add
   IS_CALLABLE_SUPPRESS_DEPRECATIONS to the check_flags parameter.
+* Registered zend_observer_fcall_init handlers are now also called for internal functions.
 
 ========================
 2. Build system changes

Zend/zend.c

@@ -1226,6 +1226,7 @@ ZEND_API void zend_activate(void) /* {{{ */
 	if (CG(map_ptr_last)) {
 		memset(CG(map_ptr_real_base), 0, CG(map_ptr_last) * sizeof(void*));
 	}
+	zend_init_internal_run_time_cache();
 	zend_observer_activate();
 }
 /* }}} */

Zend/zend_API.c

@@ -2694,6 +2694,11 @@ ZEND_API zend_result zend_register_functions(zend_class_entry *scope, const zend
 		internal_function->scope = scope;
 		internal_function->prototype = NULL;
 		internal_function->attributes = NULL;
+		if (EG(active)) { // at run-time: this ought to only happen if registered with dl() or somehow temporarily at runtime
+			ZEND_MAP_PTR_INIT(internal_function->run_time_cache, zend_arena_alloc(&CG(arena), zend_internal_run_time_cache_reserved_size()));
+		} else {
+			ZEND_MAP_PTR_NEW(internal_function->run_time_cache);
+		}
 		if (ptr->flags) {
 			if (!(ptr->flags & ZEND_ACC_PPP_MASK)) {
 				if (ptr->flags != ZEND_ACC_DEPRECATED && scope) {

Zend/zend_compile.c

@@ -33,6 +33,7 @@
 #include "zend_inheritance.h"
 #include "zend_vm.h"
 #include "zend_enum.h"
+#include "zend_observer.h"
 
 #define SET_NODE(target, src) do { \
 		target ## _type = (src)->op_type; \

Zend/zend_compile.h

@@ -448,6 +448,7 @@ struct _zend_op_array {
 	uint32_t required_num_args;
 	zend_arg_info *arg_info;
 	HashTable *attributes;
+	ZEND_MAP_PTR_DEF(void **, run_time_cache);
 	/* END of common elements */
 
 	int cache_size;     /* number of run_time_cache_slots * sizeof(void*) */
@@ -456,7 +457,6 @@ struct _zend_op_array {
 	uint32_t last;      /* number of opcodes */
 
 	zend_op *opcodes;
-	ZEND_MAP_PTR_DEF(void **, run_time_cache);
 	ZEND_MAP_PTR_DEF(HashTable *, static_variables_ptr);
 	HashTable *static_variables;
 	zend_string **vars; /* names of CV variables */
@@ -503,6 +503,7 @@ typedef struct _zend_internal_function {
 	uint32_t required_num_args;
 	zend_internal_arg_info *arg_info;
 	HashTable *attributes;
+	ZEND_MAP_PTR_DEF(void **, run_time_cache);
 	/* END of common elements */
 
 	zif_handler handler;
@@ -527,6 +528,7 @@ union _zend_function {
 		uint32_t required_num_args;
 		zend_arg_info *arg_info;  /* index -1 represents the return value info, if any */
 		HashTable   *attributes;
+		ZEND_MAP_PTR_DEF(void **, run_time_cache);
 	} common;
 
 	zend_op_array op_array;

Zend/zend_enum.c

@@ -22,6 +22,7 @@
 #include "zend_enum_arginfo.h"
 #include "zend_interfaces.h"
 #include "zend_enum.h"
+#include "zend_extensions.h"
 
 #define ZEND_ENUM_DISALLOW_MAGIC_METHOD(propertyName, methodName) \
 	do { \
@@ -401,59 +402,48 @@ static ZEND_NAMED_FUNCTION(zend_enum_try_from_func)
 	zend_enum_from_base(INTERNAL_FUNCTION_PARAM_PASSTHRU, 1);
 }
 
+static void zend_enum_register_func(zend_class_entry *ce, zend_known_string_id name_id, zend_internal_function *zif) {
+	zend_string *name = ZSTR_KNOWN(name_id);
+	zif->type = ZEND_INTERNAL_FUNCTION;
+	zif->module = EG(current_module);
+	zif->scope = ce;
+	ZEND_MAP_PTR_NEW(zif->run_time_cache);
+	ZEND_MAP_PTR_SET(zif->run_time_cache, zend_arena_alloc(&CG(arena), zend_internal_run_time_cache_reserved_size()));
+
+	if (!zend_hash_add_ptr(&ce->function_table, name, zif)) {
+		zend_error_noreturn(E_COMPILE_ERROR, "Cannot redeclare %s::%s()", ZSTR_VAL(ce->name), ZSTR_VAL(name));
+	}
+}
+
 void zend_enum_register_funcs(zend_class_entry *ce)
 {
 	const uint32_t fn_flags =
 		ZEND_ACC_PUBLIC|ZEND_ACC_STATIC|ZEND_ACC_HAS_RETURN_TYPE|ZEND_ACC_ARENA_ALLOCATED;
-	zend_internal_function *cases_function =
-		zend_arena_alloc(&CG(arena), sizeof(zend_internal_function));
-	memset(cases_function, 0, sizeof(zend_internal_function));
-	cases_function->type = ZEND_INTERNAL_FUNCTION;
-	cases_function->module = EG(current_module);
+	zend_internal_function *cases_function = zend_arena_calloc(&CG(arena), sizeof(zend_internal_function), 1);
 	cases_function->handler = zend_enum_cases_func;
 	cases_function->function_name = ZSTR_KNOWN(ZEND_STR_CASES);
-	cases_function->scope = ce;
 	cases_function->fn_flags = fn_flags;
 	cases_function->arg_info = (zend_internal_arg_info *) (arginfo_class_UnitEnum_cases + 1);
-	if (!zend_hash_add_ptr(&ce->function_table, ZSTR_KNOWN(ZEND_STR_CASES), cases_function)) {
-		zend_error_noreturn(E_COMPILE_ERROR, "Cannot redeclare %s::cases()", ZSTR_VAL(ce->name));
-	}
+	zend_enum_register_func(ce, ZEND_STR_CASES, cases_function);
 
 	if (ce->enum_backing_type != IS_UNDEF) {
-		zend_internal_function *from_function =
-			zend_arena_alloc(&CG(arena), sizeof(zend_internal_function));
-		memset(from_function, 0, sizeof(zend_internal_function));
-		from_function->type = ZEND_INTERNAL_FUNCTION;
-		from_function->module = EG(current_module);
+		zend_internal_function *from_function = zend_arena_calloc(&CG(arena), sizeof(zend_internal_function), 1);
 		from_function->handler = zend_enum_from_func;
 		from_function->function_name = ZSTR_KNOWN(ZEND_STR_FROM);
-		from_function->scope = ce;
 		from_function->fn_flags = fn_flags;
 		from_function->num_args = 1;
 		from_function->required_num_args = 1;
 		from_function->arg_info = (zend_internal_arg_info *) (arginfo_class_BackedEnum_from + 1);
-		if (!zend_hash_add_ptr(&ce->function_table, ZSTR_KNOWN(ZEND_STR_FROM), from_function)) {
-			zend_error_noreturn(E_COMPILE_ERROR,
-				"Cannot redeclare %s::from()", ZSTR_VAL(ce->name));
-		}
+		zend_enum_register_func(ce, ZEND_STR_FROM, from_function);
 
-		zend_internal_function *try_from_function =
-			zend_arena_alloc(&CG(arena), sizeof(zend_internal_function));
-		memset(try_from_function, 0, sizeof(zend_internal_function));
-		try_from_function->type = ZEND_INTERNAL_FUNCTION;
-		try_from_function->module = EG(current_module);
+		zend_internal_function *try_from_function = zend_arena_calloc(&CG(arena), sizeof(zend_internal_function), 1);
 		try_from_function->handler = zend_enum_try_from_func;
 		try_from_function->function_name = ZSTR_KNOWN(ZEND_STR_TRYFROM);
-		try_from_function->scope = ce;
 		try_from_function->fn_flags = fn_flags;
 		try_from_function->num_args = 1;
 		try_from_function->required_num_args = 1;
 		try_from_function->arg_info = (zend_internal_arg_info *) (arginfo_class_BackedEnum_tryFrom + 1);
-		if (!zend_hash_add_ptr(
-				&ce->function_table, ZSTR_KNOWN(ZEND_STR_TRYFROM_LOWERCASE), try_from_function)) {
-			zend_error_noreturn(E_COMPILE_ERROR,
-				"Cannot redeclare %s::tryFrom()", ZSTR_VAL(ce->name));
-		}
+		zend_enum_register_func(ce, ZEND_STR_TRYFROM_LOWERCASE, try_from_function);
 	}
 }
 

Zend/zend_execute.c

@@ -144,6 +144,7 @@ ZEND_API const zend_internal_function zend_pass_function = {
 	0,                      /* required_num_args */
 	(zend_internal_arg_info *) zend_pass_function_arg_info + 1, /* arg_info */
 	NULL,                   /* attributes        */
+	NULL,                   /* run_time_cache    */
 	ZEND_FN(pass),          /* handler           */
 	NULL,                   /* module            */
 	{NULL,NULL,NULL,NULL}   /* reserved          */

Zend/zend_execute_API.c

@@ -935,6 +935,7 @@ zend_result zend_call_function(zend_fcall_info *fci, zend_fcall_info_cache *fci_
 #if ZEND_DEBUG
 		bool should_throw = zend_internal_call_should_throw(func, call);
 #endif
+		ZEND_OBSERVER_FCALL_BEGIN(call);
 		if (EXPECTED(zend_execute_internal == NULL)) {
 			/* saves one function call if zend_execute_internal is not used */
 			func->internal_function.handler(call, fci->retval);
@@ -953,6 +954,7 @@ zend_result zend_call_function(zend_fcall_info *fci, zend_fcall_info_cache *fci_
 				? Z_ISREF_P(fci->retval) : !Z_ISREF_P(fci->retval));
 		}
 #endif
+		ZEND_OBSERVER_FCALL_END(call, fci->retval);
 		EG(current_execute_data) = call->prev_execute_data;
 		zend_vm_stack_free_args(call);
 		if (UNEXPECTED(ZEND_CALL_INFO(call) & ZEND_CALL_HAS_EXTRA_NAMED_PARAMS)) {

Zend/zend_extensions.c

@@ -280,6 +280,40 @@ ZEND_API int zend_get_op_array_extension_handles(const char *module_name, int ha
 	return handle;
 }
 
+ZEND_API size_t zend_internal_run_time_cache_reserved_size() {
+	return zend_op_array_extension_handles * sizeof(void *);
+}
+
+ZEND_API void zend_init_internal_run_time_cache() {
+	size_t rt_size = zend_internal_run_time_cache_reserved_size();
+	if (rt_size) {
+		size_t functions = zend_hash_num_elements(CG(function_table));
+		zend_class_entry *ce;
+		ZEND_HASH_MAP_FOREACH_PTR(CG(class_table), ce) {
+			functions += zend_hash_num_elements(&ce->function_table);
+		} ZEND_HASH_FOREACH_END();
+
+		char *ptr = zend_arena_calloc(&CG(arena), functions, rt_size);
+		zend_internal_function *zif;
+		ZEND_HASH_MAP_FOREACH_PTR(CG(function_table), zif) {
+			if (!ZEND_USER_CODE(zif->type) && ZEND_MAP_PTR_GET(zif->run_time_cache) == NULL)
+			{
+				ZEND_MAP_PTR_SET(zif->run_time_cache, (void *)ptr);
+				ptr += rt_size;
+			}
+		} ZEND_HASH_FOREACH_END();
+		ZEND_HASH_MAP_FOREACH_PTR(CG(class_table), ce) {
+			ZEND_HASH_MAP_FOREACH_PTR(&ce->function_table, zif) {
+				if (!ZEND_USER_CODE(zif->type) && ZEND_MAP_PTR_GET(zif->run_time_cache) == NULL)
+				{
+					ZEND_MAP_PTR_SET(zif->run_time_cache, (void *)ptr);
+					ptr += rt_size;
+				}
+			} ZEND_HASH_FOREACH_END();
+		} ZEND_HASH_FOREACH_END();
+	}
+}
+
 ZEND_API zend_extension *zend_get_extension(const char *extension_name)
 {
 	zend_llist_element *element;

Zend/zend_extensions.h

@@ -145,6 +145,9 @@ void zend_startup_extensions_mechanism(void);
 void zend_startup_extensions(void);
 void zend_shutdown_extensions(void);
 
+ZEND_API size_t zend_internal_run_time_cache_reserved_size(void);
+ZEND_API void zend_init_internal_run_time_cache(void);
+
 BEGIN_EXTERN_C()
 ZEND_API zend_result zend_load_extension(const char *path);
 ZEND_API zend_result zend_load_extension_handle(DL_HANDLE handle, const char *path);

Zend/zend_observer.c

@@ -23,13 +23,13 @@
 #include "zend_llist.h"
 #include "zend_vm.h"
 
-#define ZEND_OBSERVER_DATA(op_array) \
-	ZEND_OP_ARRAY_EXTENSION(op_array, zend_observer_fcall_op_array_extension)
+#define ZEND_OBSERVER_DATA(function) \
+	ZEND_OP_ARRAY_EXTENSION((&(function)->common), zend_observer_fcall_op_array_extension)
 
 #define ZEND_OBSERVER_NOT_OBSERVED ((void *) 2)
 
-#define ZEND_OBSERVABLE_FN(fn_flags) \
-	(!(fn_flags & ZEND_ACC_CALL_VIA_TRAMPOLINE))
+#define ZEND_OBSERVABLE_FN(function) \
+	(ZEND_MAP_PTR(function->common.run_time_cache) && !(function->common.fn_flags & ZEND_ACC_CALL_VIA_TRAMPOLINE))
 
 zend_llist zend_observers_fcall_list;
 zend_llist zend_observer_error_callbacks;
@@ -100,12 +100,9 @@ static void zend_observer_fcall_install(zend_execute_data *execute_data)
 {
 	zend_llist *list = &zend_observers_fcall_list;
 	zend_function *function = execute_data->func;
-	zend_op_array *op_array = &function->op_array;
 
-	ZEND_ASSERT(function->type != ZEND_INTERNAL_FUNCTION);
-
-	ZEND_ASSERT(RUN_TIME_CACHE(op_array));
-	zend_observer_fcall_begin_handler *begin_handlers = (zend_observer_fcall_begin_handler *)&ZEND_OBSERVER_DATA(op_array);
+	ZEND_ASSERT(RUN_TIME_CACHE(&function->common));
+	zend_observer_fcall_begin_handler *begin_handlers = (zend_observer_fcall_begin_handler *)&ZEND_OBSERVER_DATA(function);
 	zend_observer_fcall_end_handler *end_handlers = (zend_observer_fcall_end_handler *)begin_handlers + list->count, *end_handlers_start = end_handlers;
 
 	*begin_handlers = ZEND_OBSERVER_NOT_OBSERVED;
@@ -152,9 +149,9 @@ static bool zend_observer_remove_handler(void **first_handler, void *old_handler
 	return false;
 }
 
-ZEND_API void zend_observer_add_begin_handler(zend_op_array *op_array, zend_observer_fcall_begin_handler begin) {
+ZEND_API void zend_observer_add_begin_handler(zend_function *function, zend_observer_fcall_begin_handler begin) {
 	size_t registered_observers = zend_observers_fcall_list.count;
-	zend_observer_fcall_begin_handler *first_handler = (void *)&ZEND_OBSERVER_DATA(op_array), *last_handler = first_handler + registered_observers - 1;
+	zend_observer_fcall_begin_handler *first_handler = (void *)&ZEND_OBSERVER_DATA(function), *last_handler = first_handler + registered_observers - 1;
 	if (*first_handler == ZEND_OBSERVER_NOT_OBSERVED) {
 		*first_handler = begin;
 	} else {
@@ -169,13 +166,13 @@ ZEND_API void zend_observer_add_begin_handler(zend_op_array *op_array, zend_obse
 	}
 }
 
-ZEND_API bool zend_observer_remove_begin_handler(zend_op_array *op_array, zend_observer_fcall_begin_handler begin) {
-	return zend_observer_remove_handler((void **)&ZEND_OBSERVER_DATA(op_array), begin);
+ZEND_API bool zend_observer_remove_begin_handler(zend_function *function, zend_observer_fcall_begin_handler begin) {
+	return zend_observer_remove_handler((void **)&ZEND_OBSERVER_DATA(function), begin);
 }
 
-ZEND_API void zend_observer_add_end_handler(zend_op_array *op_array, zend_observer_fcall_end_handler end) {
+ZEND_API void zend_observer_add_end_handler(zend_function *function, zend_observer_fcall_end_handler end) {
 	size_t registered_observers = zend_observers_fcall_list.count;
-	zend_observer_fcall_end_handler *end_handler = (zend_observer_fcall_end_handler *)&ZEND_OBSERVER_DATA(op_array) + registered_observers;
+	zend_observer_fcall_end_handler *end_handler = (zend_observer_fcall_end_handler *)&ZEND_OBSERVER_DATA(function) + registered_observers;
 	// to allow to preserve the invariant that end handlers are in reverse order of begin handlers, push the new end handler in front
 	if (*end_handler != ZEND_OBSERVER_NOT_OBSERVED) {
 		// there's no space for new handlers, then it's forbidden to call this function
@@ -185,9 +182,9 @@ ZEND_API void zend_observer_add_end_handler(zend_op_array *op_array, zend_observ
 	*end_handler = end;
 }
 
-ZEND_API bool zend_observer_remove_end_handler(zend_op_array *op_array, zend_observer_fcall_end_handler end) {
+ZEND_API bool zend_observer_remove_end_handler(zend_function *function, zend_observer_fcall_end_handler end) {
 	size_t registered_observers = zend_observers_fcall_list.count;
-	return zend_observer_remove_handler((void **)&ZEND_OBSERVER_DATA(op_array) + registered_observers, end);
+	return zend_observer_remove_handler((void **)&ZEND_OBSERVER_DATA(function) + registered_observers, end);
 }
 
 static void ZEND_FASTCALL _zend_observe_fcall_begin(zend_execute_data *execute_data)
@@ -196,14 +193,13 @@ static void ZEND_FASTCALL _zend_observe_fcall_begin(zend_execute_data *execute_d
 		return;
 	}
 
-	zend_op_array *op_array = &execute_data->func->op_array;
-	uint32_t fn_flags = op_array->fn_flags;
+	zend_function *function = execute_data->func;
 
-	if (!ZEND_OBSERVABLE_FN(fn_flags)) {
+	if (!ZEND_OBSERVABLE_FN(function)) {
 		return;
 	}
 
-	zend_observer_fcall_begin_handler *handler = (zend_observer_fcall_begin_handler *)&ZEND_OBSERVER_DATA(op_array);
+	zend_observer_fcall_begin_handler *handler = (zend_observer_fcall_begin_handler *)&ZEND_OBSERVER_DATA(function);
 	if (!*handler) {
 		zend_observer_fcall_install(execute_data);
 	}
@@ -243,11 +239,11 @@ ZEND_API void ZEND_FASTCALL zend_observer_fcall_begin(zend_execute_data *execute
 static inline bool zend_observer_is_skipped_frame(zend_execute_data *execute_data) {
 	zend_function *func = execute_data->func;
 
-	if (!func || func->type == ZEND_INTERNAL_FUNCTION || !ZEND_OBSERVABLE_FN(func->common.fn_flags)) {
+	if (!func || !ZEND_OBSERVABLE_FN(func)) {
 		return true;
 	}
 
-	zend_observer_fcall_end_handler end_handler = (&ZEND_OBSERVER_DATA(&func->op_array))[zend_observers_fcall_list.count];
+	zend_observer_fcall_end_handler end_handler = (&ZEND_OBSERVER_DATA(func))[zend_observers_fcall_list.count];
 	if (end_handler == NULL || end_handler == ZEND_OBSERVER_NOT_OBSERVED) {
 		return true;
 	}
@@ -259,11 +255,11 @@ ZEND_API void ZEND_FASTCALL zend_observer_fcall_end(zend_execute_data *execute_d
 {
 	zend_function *func = execute_data->func;
 
-	if (!ZEND_OBSERVER_ENABLED || !ZEND_OBSERVABLE_FN(func->common.fn_flags)) {
+	if (!ZEND_OBSERVER_ENABLED || !ZEND_OBSERVABLE_FN(func)) {
 		return;
 	}
 
-	zend_observer_fcall_end_handler *handler = (zend_observer_fcall_end_handler *)&ZEND_OBSERVER_DATA(&func->op_array) + zend_observers_fcall_list.count;
+	zend_observer_fcall_end_handler *handler = (zend_observer_fcall_end_handler *)&ZEND_OBSERVER_DATA(func) + zend_observers_fcall_list.count;
 	// TODO: Fix exceptions from generators
 	// ZEND_ASSERT(fcall_data);
 	if (!*handler || *handler == ZEND_OBSERVER_NOT_OBSERVED) {
@@ -291,7 +287,7 @@ ZEND_API void zend_observer_fcall_end_all(void)
 {
 	zend_execute_data *ex = current_observed_frame;
 	while (ex != NULL) {
-		if (ex->func && ex->func->type != ZEND_INTERNAL_FUNCTION) {
+		if (ex->func) {
 			zend_observer_fcall_end(ex, NULL);
 		}
 		ex = ex->prev_execute_data;

Zend/zend_observer.h

@@ -58,10 +58,10 @@ ZEND_API void zend_observer_fcall_register(zend_observer_fcall_init);
 
 // Call during runtime, but only if you have used zend_observer_fcall_register.
 // You must not have more than one begin and one end handler active at the same time. Remove the old one first, if there is an existing one.
-ZEND_API void zend_observer_add_begin_handler(zend_op_array *op_array, zend_observer_fcall_begin_handler begin);
-ZEND_API bool zend_observer_remove_begin_handler(zend_op_array *op_array, zend_observer_fcall_begin_handler begin);
-ZEND_API void zend_observer_add_end_handler(zend_op_array *op_array, zend_observer_fcall_end_handler end);
-ZEND_API bool zend_observer_remove_end_handler(zend_op_array *op_array, zend_observer_fcall_end_handler end);
+ZEND_API void zend_observer_add_begin_handler(zend_function *function, zend_observer_fcall_begin_handler begin);
+ZEND_API bool zend_observer_remove_begin_handler(zend_function *function, zend_observer_fcall_begin_handler begin);
+ZEND_API void zend_observer_add_end_handler(zend_function *function, zend_observer_fcall_end_handler end);
+ZEND_API bool zend_observer_remove_end_handler(zend_function *function, zend_observer_fcall_end_handler end);
 
 ZEND_API void zend_observer_startup(void); // Called by engine before MINITs
 ZEND_API void zend_observer_post_startup(void); // Called by engine after MINITs