From patchwork Wed Aug 30 10:37:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Duan, Zhenzhong" X-Patchwork-Id: 13370175 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BC5A1C6FA8F for ; Wed, 30 Aug 2023 10:56:50 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qbIpt-00063a-Bt; Wed, 30 Aug 2023 06:54:09 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qbIps-000629-JM for qemu-devel@nongnu.org; Wed, 30 Aug 2023 06:54:08 -0400 Received: from mgamail.intel.com ([192.55.52.93]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qbIpp-0007jy-Rd for qemu-devel@nongnu.org; Wed, 30 Aug 2023 06:54:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1693392845; x=1724928845; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=W3wp6+6pVnRTM7wP/U9b4HQwamgiP4qP/FnE9wLdssg=; b=efEcxBbo+6zB5t2t+mBBINSim1r8t9z58+FWsTgF6rsgO9EzEbub6Lra MoAn1/OcJeGWW5z6S6dbCfgWMnRlZlFfD7XhFex+F6Sm0mEi5tab9ZcoF 3zsYRVkGOvjH1z6D7700pQPNdmkDawdDARe9hJ0viCrSiJ3LUzq8SzsEJ hhSVP3MTB36vsLWoxj7ONlo61KL/p4ihptLR6xzY+NVr7y2ZTU0iTRF3W mITVdMDr9za1nWg1MxYYFWgFSrVXE6mmAFNOZutO/tDLcaUDRBZDLUVfQ hhVgoRS/G3gmE43tA0vcBg62GcMwuZjj6PUOIvGlOopox4Nj2m7/aLpP0 g==; X-IronPort-AV: E=McAfee;i="6600,9927,10817"; a="373016680" X-IronPort-AV: E=Sophos;i="6.02,213,1688454000"; d="scan'208";a="373016680" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Aug 2023 03:53:48 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10817"; a="715866261" X-IronPort-AV: E=Sophos;i="6.02,213,1688454000"; d="scan'208";a="715866261" Received: from duan-server-s2600bt.bj.intel.com ([10.240.192.147]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Aug 2023 03:53:44 -0700 From: Zhenzhong Duan To: qemu-devel@nongnu.org Cc: alex.williamson@redhat.com, clg@redhat.com, jgg@nvidia.com, nicolinc@nvidia.com, joao.m.martins@oracle.com, eric.auger@redhat.com, peterx@redhat.com, jasowang@redhat.com, kevin.tian@intel.com, yi.l.liu@intel.com, yi.y.sun@intel.com, chao.p.peng@intel.com, Zhenzhong Duan Subject: [PATCH v1 17/22] util/char_dev: Add open_cdev() Date: Wed, 30 Aug 2023 18:37:49 +0800 Message-Id: <20230830103754.36461-18-zhenzhong.duan@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230830103754.36461-1-zhenzhong.duan@intel.com> References: <20230830103754.36461-1-zhenzhong.duan@intel.com> MIME-Version: 1.0 Received-SPF: pass client-ip=192.55.52.93; envelope-from=zhenzhong.duan@intel.com; helo=mgamail.intel.com X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Yi Liu /dev/vfio/devices/vfioX may not exist. In that case it is still possible to open /dev/char/$major:$minor instead. Add helper function to abstract the cdev open. Suggested-by: Jason Gunthorpe Signed-off-by: Yi Liu Signed-off-by: Zhenzhong Duan --- MAINTAINERS | 6 ++++ include/qemu/char_dev.h | 16 +++++++++++ util/chardev_open.c | 61 +++++++++++++++++++++++++++++++++++++++++ util/meson.build | 1 + 4 files changed, 84 insertions(+) create mode 100644 include/qemu/char_dev.h create mode 100644 util/chardev_open.c diff --git a/MAINTAINERS b/MAINTAINERS index 04663fbb6f..74d18593fe 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3372,6 +3372,12 @@ S: Maintained F: include/qemu/iova-tree.h F: util/iova-tree.c +cdev Open +M: Yi Liu +S: Maintained +F: include/qemu/char_dev.h +F: util/chardev_open.c + elf2dmp M: Viktor Prutyanov S: Maintained diff --git a/include/qemu/char_dev.h b/include/qemu/char_dev.h new file mode 100644 index 0000000000..6580d351c6 --- /dev/null +++ b/include/qemu/char_dev.h @@ -0,0 +1,16 @@ +/* + * QEMU Chardev Helper + * + * Copyright (C) 2023 Intel Corporation. + * + * Authors: Yi Liu + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + */ + +#ifndef QEMU_CHARDEV_HELPERS_H +#define QEMU_CHARDEV_HELPERS_H + +int open_cdev(const char *devpath, dev_t cdev); +#endif diff --git a/util/chardev_open.c b/util/chardev_open.c new file mode 100644 index 0000000000..d03e415131 --- /dev/null +++ b/util/chardev_open.c @@ -0,0 +1,61 @@ +/* + * Copyright (C) 2023 Intel Corporation. + * Copyright (c) 2019, Mellanox Technologies. All rights reserved. + * + * Authors: Yi Liu + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + * Copied from + * https://github.com/linux-rdma/rdma-core/blob/master/util/open_cdev.c + * + */ +#ifndef _GNU_SOURCE +#define _GNU_SOURCE +#endif +#include "qemu/osdep.h" +#include "qemu/char_dev.h" + +static int open_cdev_internal(const char *path, dev_t cdev) +{ + struct stat st; + int fd; + + fd = qemu_open_old(path, O_RDWR); + if (fd == -1) { + return -1; + } + if (fstat(fd, &st) || !S_ISCHR(st.st_mode) || + (cdev != 0 && st.st_rdev != cdev)) { + close(fd); + return -1; + } + return fd; +} + +static int open_cdev_robust(dev_t cdev) +{ + char *devpath; + int ret; + + /* + * This assumes that udev is being used and is creating the /dev/char/ + * symlinks. + */ + devpath = g_strdup_printf("/dev/char/%u:%u", major(cdev), minor(cdev)); + ret = open_cdev_internal(devpath, cdev); + g_free(devpath); + return ret; +} + +int open_cdev(const char *devpath, dev_t cdev) +{ + int fd; + + fd = open_cdev_internal(devpath, cdev); + if (fd == -1 && cdev != 0) { + return open_cdev_robust(cdev); + } + return fd; +} diff --git a/util/meson.build b/util/meson.build index a375160286..d5313d858f 100644 --- a/util/meson.build +++ b/util/meson.build @@ -107,6 +107,7 @@ if have_block util_ss.add(files('filemonitor-stub.c')) endif util_ss.add(when: 'CONFIG_LINUX', if_true: files('vfio-helpers.c')) + util_ss.add(when: 'CONFIG_LINUX', if_true: files('chardev_open.c')) endif if cpu == 'aarch64'