From patchwork Thu Oct 26 10:30:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Duan, Zhenzhong" X-Patchwork-Id: 1855747 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=IQjFYcO9; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=patchwork.ozlabs.org) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4SGMxd1Jgwz23jV for ; Thu, 26 Oct 2023 21:49:41 +1100 (AEDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qvxuz-0003M7-Lz; Thu, 26 Oct 2023 06:48:50 -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 1qvxuh-0002Rv-Ej for qemu-devel@nongnu.org; Thu, 26 Oct 2023 06:48:35 -0400 Received: from mgamail.intel.com ([134.134.136.126]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qvxuc-0001PR-Sq for qemu-devel@nongnu.org; Thu, 26 Oct 2023 06:48:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1698317306; x=1729853306; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=rYliQG+s2p5FvOjNi6C3BSCV4OUXauhKWAFwOAi35j0=; b=IQjFYcO9Zq0TU3BNgnDa6dcEIGHCKL0Ah3y8pJh3S5AggBjaicRfoBDs ZacSRIv59r7bg2bsfOAEmQPwS02DAZQZSKvIQdyA8bCEghS97HWOPBQe/ gwSI11cA9GLRXZ6cAy62KG3NP6yZWFALZ9ZItThccdvyUX3i5EzAO5XMv lcOs52RmmYTyLNmWEFJVG4IlPfgCQQ2D5JJU3829fnqIg286J1UhYUmI4 YdYAACiYTkHbZcN7RBUPs0uA8n65JZjQCOJMf/WxG8+F2oMVdwWBI+p1x 1di2B0VReKWSUQNUc4E8WxEhGHhOcLipvJYICY+VCpVvFaTmCMXG5Ypln w==; X-IronPort-AV: E=McAfee;i="6600,9927,10874"; a="372563700" X-IronPort-AV: E=Sophos;i="6.03,253,1694761200"; d="scan'208";a="372563700" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Oct 2023 03:47:52 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.03,253,1694761200"; d="scan'208";a="463784" Received: from duan-server-s2600bt.bj.intel.com ([10.240.192.147]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Oct 2023 03:47:38 -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 v3 25/37] util/char_dev: Add open_cdev() Date: Thu, 26 Oct 2023 18:30:52 +0800 Message-Id: <20231026103104.1686921-26-zhenzhong.duan@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231026103104.1686921-1-zhenzhong.duan@intel.com> References: <20231026103104.1686921-1-zhenzhong.duan@intel.com> MIME-Version: 1.0 Received-SPF: pass client-ip=134.134.136.126; envelope-from=zhenzhong.duan@intel.com; helo=mgamail.intel.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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, 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+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.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 Signed-off-by: Cédric Le Goater --- MAINTAINERS | 6 +++ include/qemu/chardev_open.h | 16 ++++++++ util/chardev_open.c | 81 +++++++++++++++++++++++++++++++++++++ util/meson.build | 1 + 4 files changed, 104 insertions(+) create mode 100644 include/qemu/chardev_open.h create mode 100644 util/chardev_open.c diff --git a/MAINTAINERS b/MAINTAINERS index 7aa57ab16f..123e999bee 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3447,6 +3447,12 @@ S: Maintained F: include/qemu/iova-tree.h F: util/iova-tree.c +cdev Open +M: Yi Liu +S: Maintained +F: include/qemu/chardev_open.h +F: util/chardev_open.c + elf2dmp M: Viktor Prutyanov S: Maintained diff --git a/include/qemu/chardev_open.h b/include/qemu/chardev_open.h new file mode 100644 index 0000000000..6580d351c6 --- /dev/null +++ b/include/qemu/chardev_open.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..005d2b81bd --- /dev/null +++ b/util/chardev_open.c @@ -0,0 +1,81 @@ +/* + * Copyright (c) 2019, Mellanox Technologies. All rights reserved. + * Copyright (C) 2023 Intel Corporation. + * + * This software is available to you under a choice of one of two + * licenses. You may choose to be licensed under the terms of the GNU + * General Public License (GPL) Version 2, available from the file + * COPYING in the main directory of this source tree, or the + * OpenIB.org BSD license below: + * + * Redistribution and use in source and binary forms, with or + * without modification, are permitted provided that the following + * conditions are met: + * + * - Redistributions of source code must retain the above + * copyright notice, this list of conditions and the following + * disclaimer. + * + * - Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials + * provided with the distribution. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + * + * Authors: Yi Liu + * + * Copied from + * https://github.com/linux-rdma/rdma-core/blob/master/util/open_cdev.c + * + */ + +#include "qemu/osdep.h" +#include "qemu/chardev_open.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) +{ + g_autofree char *devpath; + + /* + * 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)); + return open_cdev_internal(devpath, cdev); +} + +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 eb677b40c2..eda0b06062 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'