Fix GH-16041: Support stack limit in phpdbg SAPI

Zend/tests/stack_limit/gh16041_001.phpt

@@ -0,0 +1,39 @@
+--TEST--
+GH-16041 001: Stack overflow in phpdbg
+--SKIPIF--
+<?php
+if (ini_get('zend.max_allowed_stack_size') === false) {
+    die('skip No stack limit support');
+}
+?>
+--INI--
+zend.max_allowed_stack_size=512K
+--PHPDBG--
+set pagination off
+run
+continue
+quit
+--FILE--
+<?php
+
+class Canary {
+    public function __destruct() {
+        new Canary();
+    }
+}
+
+new Canary();
+
+?>
+--EXPECTF--
+[Successful compilation of %sgh16041_001.php]
+prompt> prompt> [Uncaught Error in %s on line %d: Maximum call stack size of %d bytes%s
+>00005:         new Canary();
+ 00006:     }
+ 00007: }
+prompt> [Uncaught Error in %s on line %d]
+Error: Maximum call stack size of %d bytes (zend.max_allowed_stack_size - zend.reserved_stack_size) reached. Infinite recursion? in %s:%d
+Stack trace:
+#0 %s(%d): Canary->__destruct()
+%a
+prompt>

Zend/tests/stack_limit/gh16041_002.phpt

@@ -0,0 +1,33 @@
+--TEST--
+GH-16041 002: Stack overflow in phpdbg
+--SKIPIF--
+<?php
+if (ini_get('zend.max_allowed_stack_size') === false) {
+    die('skip No stack limit support');
+}
+?>
+--INI--
+zend.max_allowed_stack_size=512K
+--PHPDBG--
+set pagination off
+run
+quit
+--FILE--
+<?php
+
+function map() {
+    array_map('map', [1]);
+}
+
+try {
+    map();
+} catch (\Throwable $e) {
+    printf("%s: %s\n", $e::class, $e->getMessage());
+}
+
+?>
+--EXPECTF--
+[Successful compilation of %sgh16041_002.php]
+prompt> prompt> Error: Maximum call stack size of %d bytes (zend.max_allowed_stack_size - zend.reserved_stack_size) reached. Infinite recursion?
+[Script ended normally]
+prompt>

Zend/zend_execute.c

@@ -2500,7 +2500,7 @@ static zend_never_inline ZEND_COLD void ZEND_FASTCALL zend_use_new_element_for_s
 }
 
 #ifdef ZEND_CHECK_STACK_LIMIT
-static zend_never_inline ZEND_COLD void ZEND_FASTCALL zend_call_stack_size_error(void)
+zend_never_inline ZEND_COLD void ZEND_FASTCALL zend_call_stack_size_error(void)
 {
 	size_t max_stack_size = 0;
 	if ((uintptr_t) EG(stack_base) > (uintptr_t) EG(stack_limit)) {

Zend/zend_execute.h

@@ -66,6 +66,7 @@ ZEND_API ZEND_COLD void ZEND_FASTCALL zend_deprecated_class_constant(const zend_
 ZEND_API ZEND_COLD void ZEND_FASTCALL zend_false_to_array_deprecated(void);
 ZEND_COLD void ZEND_FASTCALL zend_param_must_be_ref(const zend_function *func, uint32_t arg_num);
 ZEND_API ZEND_COLD void ZEND_FASTCALL zend_use_resource_as_offset(const zval *dim);
+zend_never_inline ZEND_COLD void ZEND_FASTCALL zend_call_stack_size_error(void);
 
 ZEND_API bool ZEND_FASTCALL zend_verify_ref_assignable_zval(zend_reference *ref, zval *zv, bool strict);
 

sapi/phpdbg/phpdbg_prompt.c

@@ -1652,6 +1652,15 @@ void phpdbg_execute_ex(zend_execute_data *execute_data) /* {{{ */
 
 	PHPDBG_G(in_execution) = 1;
 
+#ifdef ZEND_CHECK_STACK_LIMIT
+	if (UNEXPECTED(zend_call_stack_overflowed(EG(stack_limit)))) {
+		zend_call_stack_size_error();
+		/* No opline was executed before exception */
+		EG(opline_before_exception) = NULL;
+		/* Fall through to handle exception below. */
+	}
+#endif /* ZEND_CHECK_STACK_LIMIT */
+
 	while (1) {
 		zend_object *exception = EG(exception);