From patchwork Fri Sep 22 08:10:10 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: 725973 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 BE794CD4F2B for ; Fri, 22 Sep 2023 08:11:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232249AbjIVILK (ORCPT ); Fri, 22 Sep 2023 04:11:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232526AbjIVIKj (ORCPT ); Fri, 22 Sep 2023 04:10:39 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D06E6170D; Fri, 22 Sep 2023 01:10:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1695370232; x=1726906232; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=+9QRUeCNbWBg9HFmG2BsNklF6qiJkbemQMortAEpZN0=; b=bPXZZJpI0L/OXoi8zdxloZ1kS0ZCgvPQqucZpKgOrTWd5PfXxSBgWQ26 AGYHsqLw3Ac8XQdG09Q74/iK9FvRENIhRSKxepEdBh/rLsHgnrEkRGpTI BofbdW0As+yd21cwIsnCKAOV7nhWtDtHf5AqlTbIjWioU0qbFkh/VzYVK Pir+o8VPJ8oNLjbngSL+kbh/k2SoECaK998V1IWxbkC4TYGb7BzkgQh6o bWU7zvuiPIjG1hDNtjRRqU0j9YWMGBrw/8p+9N/AFqnlWyT1YlmH95Phw 0Zn8YsDUXHDSP8+D0bA6A0XFL1tBhupFOXKS2o4znMrf7o1gMzewUVhVi Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10840"; a="383516255" X-IronPort-AV: E=Sophos;i="6.03,167,1694761200"; d="scan'208";a="383516255" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Sep 2023 01:10:32 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10840"; a="776766345" X-IronPort-AV: E=Sophos;i="6.03,167,1694761200"; d="scan'208";a="776766345" Received: from bmatwiej-mobl.ger.corp.intel.com (HELO wieczorr-mobl1.intel.com) ([10.213.8.2]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Sep 2023 01:10:30 -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 v4 1/2] selftests/resctrl: Fix schemata write error check Date: Fri, 22 Sep 2023 10:10:10 +0200 Message-ID: <5e17ed39ffb8d6bd530c057aa04e3ffb997573a9.1695369120.git.maciej.wieczor-retman@intel.com> 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 --- 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 | 30 ++++++++++++--------- 1 file changed, 17 insertions(+), 13 deletions(-) diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c index 3a8111362d26..edc8fc6e44b0 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], 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)) && @@ -520,27 +520,31 @@ 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) { - sprintf(reason, "Failed to open control group"); + fd = open(controlgroup, O_WRONLY); + if (!fd) { + 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",