From patchwork Mon Oct 9 10:57:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Maciej Wieczor-Retman X-Patchwork-Id: 731252 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E857FE95A91 for ; Mon, 9 Oct 2023 10:58:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345822AbjJIK6D (ORCPT ); Mon, 9 Oct 2023 06:58:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233034AbjJIK6C (ORCPT ); Mon, 9 Oct 2023 06:58:02 -0400 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3951C99; Mon, 9 Oct 2023 03:58:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1696849082; x=1728385082; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=JvWgOKieSRa2m3wAvYG2s6OPGP6R/MoBz2uR7jxcsEc=; b=UYJerSZdU/fV1QBgz0M9CGv0NnzqKzP8/QYsoKqR+Drw6t2lYbut1N0z l6K46+CGQ32HUAmI1/FCFywEt5bjOvpxVHFk1QSoCNl/v2mZw7w2mY3Ud vXITcbXtK4e2RGGvlDwat9yELAadeHHL7hPyGTSECdhORzcewh1zvb7In 75di5eMH/WJpz0JWCb9SiwD6YryfP5WEQjTdPPX/aawj55zsUCtxJhR/F xTyu5zJO/2cZSRi2qTtovt8nmGVxMyIfmUmLFfJvFALaBnAyTxTnlZBoy aBpAvkK+5n5yPWS9rl/rCEaAI+CJkDmunu1gUGmj/5O9iTO2wdRneSxp4 A==; X-IronPort-AV: E=McAfee;i="6600,9927,10857"; a="2715345" X-IronPort-AV: E=Sophos;i="6.03,210,1694761200"; d="scan'208";a="2715345" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Oct 2023 03:58:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10857"; a="926726023" X-IronPort-AV: E=Sophos;i="6.03,210,1694761200"; d="scan'208";a="926726023" Received: from kkensic-mobl1.ger.corp.intel.com (HELO wieczorr-mobl1.intel.com) ([10.213.30.239]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Oct 2023 03:57:58 -0700 From: Maciej Wieczor-Retman To: Fenghua Yu , Reinette Chatre , Shuah Khan Cc: ilpo.jarvinen@linux.intel.com, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v6 1/2] selftests/resctrl: Fix schemata write error check Date: Mon, 9 Oct 2023 12:57:11 +0200 Message-ID: X-Mailer: git-send-email 2.42.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Writing bitmasks to the schemata can fail when the bitmask doesn't adhere to constraints defined by what a particular CPU supports. Some example of constraints are max length or having contiguous bits. The driver should properly return errors when any rule concerning bitmask format is broken. Resctrl FS returns error codes from fprintf() only when fclose() is called. Current error checking scheme allows invalid bitmasks to be written into schemata file and the selftest doesn't notice because the fclose() error code isn't checked. Substitute fopen(), flose() and fprintf() with open(), close() and write() to avoid error code buffering between fprintf() and fclose(). Remove newline character from the schema string after writing it to the schemata file so it prints correctly before function return. Pass the string generated with strerror() to the "reason" buffer so the error message is more verbose. Extend "reason" buffer so it can hold longer messages. Signed-off-by: Maciej Wieczor-Retman Reviewed-by: Ilpo Järvinen Reviewed-by: Reinette Chatre --- Changelog v6: - Align schema_len error checking with typical snprintf format. (Reinette) - Initialize schema string for early return eventuality. (Reinette) Changelog v5: - Add Ilpo's reviewed-by tag. - Fix wrong open() error checking. (Reinette) - Add error checking to schema_len variable. Changelog v4: - Unify error checking between open() and write(). (Reinette) - Add fcntl.h for glibc backward compatiblitiy. (Reinette) Changelog v3: - Rename fp to fd. (Ilpo) - Remove strlen, strcspn and just use the snprintf value instead. (Ilpo) Changelog v2: - Rewrite patch message. - Double "reason" buffer size to fit longer error explanation. - Redo file interactions with syscalls instead of stdio functions. tools/testing/selftests/resctrl/resctrlfs.c | 36 +++++++++++++-------- 1 file changed, 23 insertions(+), 13 deletions(-) diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c index 3a8111362d26..648f9ec8b355 100644 --- a/tools/testing/selftests/resctrl/resctrlfs.c +++ b/tools/testing/selftests/resctrl/resctrlfs.c @@ -8,6 +8,7 @@ * Sai Praneeth Prakhya , * Fenghua Yu */ +#include #include #include "resctrl.h" @@ -490,9 +491,8 @@ int write_bm_pid_to_resctrl(pid_t bm_pid, char *ctrlgrp, char *mongrp, */ int write_schemata(char *ctrlgrp, char *schemata, int cpu_no, char *resctrl_val) { - char controlgroup[1024], schema[1024], reason[64]; - int resource_id, ret = 0; - FILE *fp; + char controlgroup[1024], reason[128], schema[1024] = {}; + int resource_id, fd, schema_len = -1, ret = 0; if (strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR)) && strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)) && @@ -520,27 +520,37 @@ int write_schemata(char *ctrlgrp, char *schemata, int cpu_no, char *resctrl_val) if (!strncmp(resctrl_val, CAT_STR, sizeof(CAT_STR)) || !strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR))) - sprintf(schema, "%s%d%c%s", "L3:", resource_id, '=', schemata); + schema_len = snprintf(schema, sizeof(schema), "%s%d%c%s\n", + "L3:", resource_id, '=', schemata); if (!strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR)) || !strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR))) - sprintf(schema, "%s%d%c%s", "MB:", resource_id, '=', schemata); + schema_len = snprintf(schema, sizeof(schema), "%s%d%c%s\n", + "MB:", resource_id, '=', schemata); + if (schema_len < 0 || schema_len >= sizeof(schema)) { + snprintf(reason, sizeof(reason), + "snprintf() failed with return value : %d", schema_len); + ret = -1; + goto out; + } - fp = fopen(controlgroup, "w"); - if (!fp) { - sprintf(reason, "Failed to open control group"); + fd = open(controlgroup, O_WRONLY); + if (fd < 0) { + snprintf(reason, sizeof(reason), + "open() failed : %s", strerror(errno)); ret = -1; goto out; } - - if (fprintf(fp, "%s\n", schema) < 0) { - sprintf(reason, "Failed to write schemata in control group"); - fclose(fp); + if (write(fd, schema, schema_len) < 0) { + snprintf(reason, sizeof(reason), + "write() failed : %s", strerror(errno)); + close(fd); ret = -1; goto out; } - fclose(fp); + close(fd); + schema[schema_len - 1] = 0; out: ksft_print_msg("Write schema \"%s\" to resctrl FS%s%s\n",