From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753042AbbAPV3k (ORCPT ); Fri, 16 Jan 2015 16:29:40 -0500 Received: from mail.savoirfairelinux.com ([209.172.62.77]:64423 "EHLO mail.savoirfairelinux.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752674AbbAPV3i (ORCPT ); Fri, 16 Jan 2015 16:29:38 -0500 From: Vivien Didelot To: linux-kernel@vger.kernel.org Cc: Vivien Didelot , Greg Kroah-Hartman , kernel@savoirfairelinux.com Subject: [PATCH] sysfs: group: allow is_visible to drop permissions Date: Fri, 16 Jan 2015 16:29:10 -0500 Message-Id: <1421443750-12935-1-git-send-email-vivien.didelot@savoirfairelinux.com> X-Mailer: git-send-email 2.2.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Using the optional is_visible function, it is actually possible to either hide an attribute, or add a new permission, but not remove one. This commit uses all the UGO bits returned by is_visible instead of OR'ing them with the default attribute mode. Concretely, this allows a driver to use macros like DEVICE_ATTR_RW to set the attribute show and store functions and remove the S_IWUSR permission in is_visible if the implementation doesn't provide a setter. Signed-off-by: Vivien Didelot --- fs/sysfs/group.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c index 7d2a860..a8cfe03 100644 --- a/fs/sysfs/group.c +++ b/fs/sysfs/group.c @@ -41,7 +41,7 @@ static int create_files(struct kernfs_node *parent, struct kobject *kobj, if (grp->attrs) { for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) { - umode_t mode = 0; + umode_t mode = (*attr)->mode; /* * In update mode, we're changing the permissions or @@ -51,13 +51,15 @@ static int create_files(struct kernfs_node *parent, struct kobject *kobj, if (update) kernfs_remove_by_name(parent, (*attr)->name); if (grp->is_visible) { - mode = grp->is_visible(kobj, *attr, i); - if (!mode) + umode_t ugo = grp->is_visible(kobj, *attr, i); + + if (!(ugo & S_IRWXUGO)) continue; + + mode = (mode & ~S_IRWXUGO) | (ugo & S_IRWXUGO); } error = sysfs_add_file_mode_ns(parent, *attr, false, - (*attr)->mode | mode, - NULL); + mode, NULL); if (unlikely(error)) break; } -- 2.2.2