void callPostHook()

in prod/native/extension/code/InternalFunctionInstrumentation.cpp [173:227]
40 lines of code
8 McCabe index (conditional complexity)

void callPostHook(AutoZval &hook, zval *return_value, zend_object *exception, zend_execute_data *execute_data) {
    zend_fcall_info fci = empty_fcall_info;
    zend_fcall_info_cache fcc = empty_fcall_info_cache;

    if (zend_fcall_info_init(const_cast<zval *>(hook.get()), 0, &fci, &fcc, nullptr, nullptr) == ZEND_RESULT_CODE::FAILURE) {
        throw std::runtime_error("Unable to initialize posthook fcall");
    }

    std::array<AutoZval, 8> parameters;
    getScopeNameOrThis(parameters[0].get(), EG(current_execute_data));
    getCallArguments(parameters[1].get(), EG(current_execute_data));
    getFunctionReturnValue(parameters[2].get(), return_value);
    getCurrentException(parameters[3].get(), exception);
    getFunctionDeclaringScope(parameters[4].get(), EG(current_execute_data));
    getFunctionName(parameters[5].get(), EG(current_execute_data));
    getFunctionDeclarationFileName(parameters[6].get(), EG(current_execute_data));
    getFunctionDeclarationLineNo(parameters[7].get(), EG(current_execute_data));

    AutoZval hookRv;
    fci.param_count = parameters.size();
    fci.params = parameters[0].get();
    fci.named_params = nullptr;
    fci.retval = hookRv.get();

    if (zend_call_function(&fci, &fcc) != SUCCESS) {
        throw std::runtime_error("Unable to call posthook function");
    }

    if (Z_TYPE_P(hookRv.get()) == IS_UNDEF) {
        return;
    }

    if (!return_value) {
        return;
    }

    // thre is no way to distinguish if posthook returned NULL, becuase in PHP functions are always returning NULL, even if there is no return keyword
    // in that case we can only try to overwrite return value for posthooks with return value type specified explicitly
    if (!(fcc.function_handler->op_array.fn_flags & ZEND_ACC_HAS_RETURN_TYPE) || (ZEND_TYPE_PURE_MASK(fcc.function_handler->common.arg_info[-1].type) & MAY_BE_VOID)) {
        ELOGF_TRACE(EAPM_GL(logger_), INSTRUMENTATION, "callPostHook hook doesn't explicitly specify return type other than void");
        return;
    }

    if (execute_data->func->op_array.fn_flags & ZEND_ACC_HAS_RETURN_TYPE) {
        // uncomment if want to block possibility of adding rv to instrumented void-rv function
        // if ((ZEND_TYPE_PURE_MASK(execute_data->func->common.arg_info[-1].type) & MAY_BE_VOID)) {
        //     return;
        // }
        bool sameType = ZEND_TYPE_CONTAINS_CODE(execute_data->func->common.arg_info[-1].type, Z_TYPE_P(hookRv.get()));
        ELOGF_DEBUG(EAPM_GL(logger_), INSTRUMENTATION, "callPostHook hasRvType: %d, isVoid: %d sameType: %d, hookRvType: %d", execute_data->func->op_array.fn_flags & ZEND_ACC_HAS_RETURN_TYPE, static_cast<bool>(ZEND_TYPE_PURE_MASK(execute_data->func->common.arg_info[-1].type) & MAY_BE_VOID), sameType, hookRv.getType());
    }

    zval_ptr_dtor(return_value);
    ZVAL_COPY(return_value, hookRv.get());
}