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a="394543410" X-IronPort-AV: E=Sophos;i="6.03,301,1694761200"; d="scan'208";a="394543410" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10893"; a="888212805" X-IronPort-AV: E=Sophos;i="6.03,301,1694761200"; d="scan'208";a="888212805" 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 v6 02/21] util/char_dev: Add open_cdev() Date: Tue, 14 Nov 2023 18:09:36 +0800 Message-Id: <20231114100955.1961974-3-zhenzhong.duan@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231114100955.1961974-1-zhenzhong.duan@intel.com> References: <20231114100955.1961974-1-zhenzhong.duan@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=134.134.136.65; 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, T_SCC_BODY_TEXT_LINE=-0.01 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @intel.com) X-ZM-MESSAGEID: 1699957808529100001 Content-Type: text/plain; charset="utf-8" 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 Reviewed-by: C=C3=A9dric Le Goater Reviewed-by: Eric Auger --- MAINTAINERS | 3 ++ include/qemu/chardev_open.h | 16 ++++++++ util/chardev_open.c | 81 +++++++++++++++++++++++++++++++++++++ util/meson.build | 1 + 4 files changed, 101 insertions(+) create mode 100644 include/qemu/chardev_open.h create mode 100644 util/chardev_open.c diff --git a/MAINTAINERS b/MAINTAINERS index a4891f7bda..869ec3d5af 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2172,6 +2172,9 @@ M: Eric Auger S: Supported F: backends/iommufd.c F: include/sysemu/iommufd.h +F: include/qemu/chardev_open.h +F: util/chardev_open.c + =20 vhost M: Michael S. Tsirkin diff --git a/include/qemu/chardev_open.h b/include/qemu/chardev_open.h new file mode 100644 index 0000000000..64e8fcfdcb --- /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_OPEN_H +#define QEMU_CHARDEV_OPEN_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..f776429788 --- /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 =3D qemu_open_old(path, O_RDWR); + if (fd =3D=3D -1) { + return -1; + } + if (fstat(fd, &st) || !S_ISCHR(st.st_mode) || + (cdev !=3D 0 && st.st_rdev !=3D cdev)) { + close(fd); + return -1; + } + return fd; +} + +static int open_cdev_robust(dev_t cdev) +{ + g_autofree char *devpath =3D NULL; + + /* + * This assumes that udev is being used and is creating the /dev/char/ + * symlinks. + */ + devpath =3D 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 =3D open_cdev_internal(devpath, cdev); + if (fd =3D=3D -1 && cdev !=3D 0) { + return open_cdev_robust(cdev); + } + return fd; +} diff --git a/util/meson.build b/util/meson.build index c2322ef6e7..174c133368 100644 --- a/util/meson.build +++ b/util/meson.build @@ -108,6 +108,7 @@ 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 =20 if cpu =3D=3D 'aarch64' --=20 2.34.1