From patchwork Fri Sep 1 13:23:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maciej Wieczor-Retman X-Patchwork-Id: 719641 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 2BAEECA0FE8 for ; Fri, 1 Sep 2023 13:24:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347179AbjIANYR (ORCPT ); Fri, 1 Sep 2023 09:24:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40776 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229985AbjIANYQ (ORCPT ); Fri, 1 Sep 2023 09:24:16 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 691F2CD8; Fri, 1 Sep 2023 06:24:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1693574654; x=1725110654; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=EEReJSRlcv9+PTEBmSIxl61qsJVklng9DcbuIC4vK8M=; b=NWpn5SmCCQPMYB1amK+Vqn+gu6pTGWQ2MXCpNj4Gj05BYyri1yyP5MQr IG4y3fyk90disUqL6hBE/xIvMK4NU+rgd3hSyd249Wsut++eWOmrlm/k9 KSkyC4E2N0bngaw7c42Nr+dlWz3JjZMbs21VrxKtw/N5tcU4+KNOinAdC bMTCGeZsvOHy6wUvNEdh6F7FIlfgRjCghMS20vDHxVNkqRAKiJsEhEMhm qXD+mxGtXnlUJ39xFEvPmM+nrL+8xLN+CjPjO7uHo69GAycuBGYTjcFuf 9fayxGncjXqrDdoFoUlHuX/6fbcCYBtoQAe73pfh7BV+O0Px4lRKwIf3E g==; X-IronPort-AV: E=McAfee;i="6600,9927,10819"; a="442613437" X-IronPort-AV: E=Sophos;i="6.02,219,1688454000"; d="scan'208";a="442613437" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Sep 2023 06:24:13 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10819"; a="883186941" X-IronPort-AV: E=Sophos;i="6.02,219,1688454000"; d="scan'208";a="883186941" Received: from rawskaal-mobl.ger.corp.intel.com (HELO wieczorr-mobl1.intel.com) ([10.213.0.136]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Sep 2023 06:24:12 -0700 From: Wieczor-Retman Maciej 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 v3 1/2] selftests/resctrl: Fix schemata write error check Date: Fri, 1 Sep 2023 15:23:27 +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: Wieczor-Retman Maciej --- 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 | 26 +++++++++++---------- 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c index bd36ee206602..b0b14a5bcbf5 100644 --- a/tools/testing/selftests/resctrl/resctrlfs.c +++ b/tools/testing/selftests/resctrl/resctrlfs.c @@ -488,9 +488,8 @@ 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], schema[1024], reason[128]; + 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)) && @@ -518,27 +517,30 @@ 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); - fp = fopen(controlgroup, "w"); - if (!fp) { + fd = open(controlgroup, O_WRONLY); + if (!fd) { sprintf(reason, "Failed to open control group"); 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",