Bug #79177 [Opn->Ver]: FFI doesn't handle well PHP exceptions within callback body

Edit report at https://bugs.php.net/bug.php?id=79177&edit=1 ID: 79177 Updated by: cmb@php.net Reported by: lisachenko dot it at gmail dot com Summary: FFI doesn't handle well PHP exceptions within callback body -Status: Open +Status: Verified Type: Bug Package: *Extensibility Functions Operating System: Unix PHP Version: 7.4.2 -Assigned To: +Assigned To: cmb Block user comment: N Private report: N Previous Comments: ------------------------------------------------------------------------ [2020-10-21 17:27:13] cmb@php.net The following pull request has been associated: Patch Name: Fix #79177: FFI doesn't handle well PHP exceptions within callback On GitHub: https://github.com/php/php-src/pull/6366 Patch: https://github.com/php/php-src/pull/6366.patch ------------------------------------------------------------------------ [2020-01-28 08:40:48] lisachenko dot it at gmail dot com Test example to reproduce this case: use FFI\CData; $php = FFI::cdef(" typedef unsigned int fake_struct; typedef fake_struct* (*zend_write_func_t)(const char *str, size_t str_length); extern zend_write_func_t zend_write; "); echo "Before", PHP_EOL; $originalHandler = clone $php->zend_write; $php->zend_write = function($str, $len): CData { throw new \RuntimeException('Not allowed'); }; try { echo "After", PHP_EOL; } catch (\Throwable $exception) { // Do not output anything here, as handler is overridden } finally { $php->zend_write = $originalHandler; } echo get_class($exception), ': ', $exception->getMessage(), PHP_EOL; // Output: // Before // FFI\Exception: Incompatible types when assigning to type 'uint32_t*' from PHP 'unknown' // Expected: // Before // RuntimeException: Not allowed ------------------------------------------------------------------------ [2020-01-27 18:46:17] requinix@php.net Example? ------------------------------------------------------------------------ [2020-01-27 18:05:51] lisachenko dot it at gmail dot com Description: ------------ If we define a C callback handler in PHP and this handler should return a pointer (not a simple value like int, float, etc), then FFI doesn't check if correct value was returned or not. For example when we throw our custom exception within callback body. This typically results in exception from FFI: Incompatible types when assigning to type 'struct some_native_type*' from PHP 'unknown' Exception is thrown because there is no check for Z_TYPE(retval) != IS_UNDEF inside FFI's function zend_ffi_callback_trampoline before call to zend_ffi_zval_to_cdata(ret, ret_type, &retval) Expected result: ---------------- Exception is thrown within callback and not from FFI itself about missing type conversion Actual result: -------------- Incompatible types when assigning to type 'struct some_native_type*' from PHP 'unknown' ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=79177&edit=1