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aac1f7f95f
Adding sysfs_update_groups function to update multiple groups. sysfs_update_groups - given a directory kobject, create a bunch of attribute groups @kobj: The kobject to update the group on @groups: The attribute groups to update, NULL terminated This function update a bunch of attribute groups. If an error occurs when updating a group, all previously updated groups will be removed together with already existing (not updated) attributes. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190512155518.21468-2-jolsa@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
460 lines
12 KiB
C
460 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* fs/sysfs/group.c - Operations for adding/removing multiple files at once.
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*
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* Copyright (c) 2003 Patrick Mochel
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* Copyright (c) 2003 Open Source Development Lab
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* Copyright (c) 2013 Greg Kroah-Hartman
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* Copyright (c) 2013 The Linux Foundation
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*/
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#include <linux/kobject.h>
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#include <linux/module.h>
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#include <linux/dcache.h>
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#include <linux/namei.h>
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#include <linux/err.h>
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#include "sysfs.h"
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static void remove_files(struct kernfs_node *parent,
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const struct attribute_group *grp)
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{
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struct attribute *const *attr;
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struct bin_attribute *const *bin_attr;
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if (grp->attrs)
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for (attr = grp->attrs; *attr; attr++)
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kernfs_remove_by_name(parent, (*attr)->name);
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if (grp->bin_attrs)
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for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
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kernfs_remove_by_name(parent, (*bin_attr)->attr.name);
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}
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static int create_files(struct kernfs_node *parent, struct kobject *kobj,
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kuid_t uid, kgid_t gid,
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const struct attribute_group *grp, int update)
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{
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struct attribute *const *attr;
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struct bin_attribute *const *bin_attr;
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int error = 0, i;
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if (grp->attrs) {
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for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
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umode_t mode = (*attr)->mode;
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/*
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* In update mode, we're changing the permissions or
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* visibility. Do this by first removing then
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* re-adding (if required) the file.
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*/
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if (update)
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kernfs_remove_by_name(parent, (*attr)->name);
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if (grp->is_visible) {
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mode = grp->is_visible(kobj, *attr, i);
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if (!mode)
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continue;
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}
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WARN(mode & ~(SYSFS_PREALLOC | 0664),
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"Attribute %s: Invalid permissions 0%o\n",
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(*attr)->name, mode);
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mode &= SYSFS_PREALLOC | 0664;
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error = sysfs_add_file_mode_ns(parent, *attr, false,
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mode, uid, gid, NULL);
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if (unlikely(error))
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break;
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}
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if (error) {
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remove_files(parent, grp);
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goto exit;
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}
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}
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if (grp->bin_attrs) {
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for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
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umode_t mode = (*bin_attr)->attr.mode;
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if (update)
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kernfs_remove_by_name(parent,
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(*bin_attr)->attr.name);
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if (grp->is_bin_visible) {
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mode = grp->is_bin_visible(kobj, *bin_attr, i);
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if (!mode)
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continue;
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}
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WARN(mode & ~(SYSFS_PREALLOC | 0664),
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"Attribute %s: Invalid permissions 0%o\n",
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(*bin_attr)->attr.name, mode);
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mode &= SYSFS_PREALLOC | 0664;
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error = sysfs_add_file_mode_ns(parent,
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&(*bin_attr)->attr, true,
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mode,
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uid, gid, NULL);
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if (error)
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break;
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}
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if (error)
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remove_files(parent, grp);
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}
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exit:
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return error;
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}
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static int internal_create_group(struct kobject *kobj, int update,
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const struct attribute_group *grp)
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{
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struct kernfs_node *kn;
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kuid_t uid;
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kgid_t gid;
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int error;
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if (WARN_ON(!kobj || (!update && !kobj->sd)))
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return -EINVAL;
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/* Updates may happen before the object has been instantiated */
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if (unlikely(update && !kobj->sd))
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return -EINVAL;
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if (!grp->attrs && !grp->bin_attrs) {
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WARN(1, "sysfs: (bin_)attrs not set by subsystem for group: %s/%s\n",
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kobj->name, grp->name ?: "");
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return -EINVAL;
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}
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kobject_get_ownership(kobj, &uid, &gid);
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if (grp->name) {
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if (update) {
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kn = kernfs_find_and_get(kobj->sd, grp->name);
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if (!kn) {
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pr_warn("Can't update unknown attr grp name: %s/%s\n",
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kobj->name, grp->name);
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return -EINVAL;
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}
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} else {
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kn = kernfs_create_dir_ns(kobj->sd, grp->name,
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S_IRWXU | S_IRUGO | S_IXUGO,
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uid, gid, kobj, NULL);
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if (IS_ERR(kn)) {
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if (PTR_ERR(kn) == -EEXIST)
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sysfs_warn_dup(kobj->sd, grp->name);
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return PTR_ERR(kn);
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}
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}
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} else
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kn = kobj->sd;
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kernfs_get(kn);
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error = create_files(kn, kobj, uid, gid, grp, update);
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if (error) {
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if (grp->name)
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kernfs_remove(kn);
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}
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kernfs_put(kn);
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if (grp->name && update)
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kernfs_put(kn);
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return error;
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}
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/**
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* sysfs_create_group - given a directory kobject, create an attribute group
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* @kobj: The kobject to create the group on
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* @grp: The attribute group to create
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*
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* This function creates a group for the first time. It will explicitly
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* warn and error if any of the attribute files being created already exist.
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*
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* Returns 0 on success or error code on failure.
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*/
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int sysfs_create_group(struct kobject *kobj,
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const struct attribute_group *grp)
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{
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return internal_create_group(kobj, 0, grp);
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}
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EXPORT_SYMBOL_GPL(sysfs_create_group);
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static int internal_create_groups(struct kobject *kobj, int update,
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const struct attribute_group **groups)
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{
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int error = 0;
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int i;
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if (!groups)
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return 0;
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for (i = 0; groups[i]; i++) {
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error = internal_create_group(kobj, update, groups[i]);
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if (error) {
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while (--i >= 0)
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sysfs_remove_group(kobj, groups[i]);
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break;
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}
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}
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return error;
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}
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/**
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* sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
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* @kobj: The kobject to create the group on
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* @groups: The attribute groups to create, NULL terminated
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*
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* This function creates a bunch of attribute groups. If an error occurs when
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* creating a group, all previously created groups will be removed, unwinding
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* everything back to the original state when this function was called.
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* It will explicitly warn and error if any of the attribute files being
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* created already exist.
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*
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* Returns 0 on success or error code from sysfs_create_group on failure.
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*/
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int sysfs_create_groups(struct kobject *kobj,
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const struct attribute_group **groups)
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{
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return internal_create_groups(kobj, 0, groups);
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}
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EXPORT_SYMBOL_GPL(sysfs_create_groups);
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/**
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* sysfs_update_groups - given a directory kobject, create a bunch of attribute groups
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* @kobj: The kobject to update the group on
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* @groups: The attribute groups to update, NULL terminated
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*
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* This function update a bunch of attribute groups. If an error occurs when
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* updating a group, all previously updated groups will be removed together
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* with already existing (not updated) attributes.
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*
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* Returns 0 on success or error code from sysfs_update_group on failure.
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*/
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int sysfs_update_groups(struct kobject *kobj,
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const struct attribute_group **groups)
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{
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return internal_create_groups(kobj, 1, groups);
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}
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EXPORT_SYMBOL_GPL(sysfs_update_groups);
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/**
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* sysfs_update_group - given a directory kobject, update an attribute group
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* @kobj: The kobject to update the group on
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* @grp: The attribute group to update
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*
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* This function updates an attribute group. Unlike
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* sysfs_create_group(), it will explicitly not warn or error if any
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* of the attribute files being created already exist. Furthermore,
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* if the visibility of the files has changed through the is_visible()
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* callback, it will update the permissions and add or remove the
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* relevant files. Changing a group's name (subdirectory name under
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* kobj's directory in sysfs) is not allowed.
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*
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* The primary use for this function is to call it after making a change
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* that affects group visibility.
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*
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* Returns 0 on success or error code on failure.
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*/
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int sysfs_update_group(struct kobject *kobj,
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const struct attribute_group *grp)
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{
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return internal_create_group(kobj, 1, grp);
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}
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EXPORT_SYMBOL_GPL(sysfs_update_group);
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/**
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* sysfs_remove_group: remove a group from a kobject
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* @kobj: kobject to remove the group from
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* @grp: group to remove
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*
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* This function removes a group of attributes from a kobject. The attributes
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* previously have to have been created for this group, otherwise it will fail.
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*/
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void sysfs_remove_group(struct kobject *kobj,
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const struct attribute_group *grp)
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{
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struct kernfs_node *parent = kobj->sd;
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struct kernfs_node *kn;
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if (grp->name) {
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kn = kernfs_find_and_get(parent, grp->name);
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if (!kn) {
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WARN(!kn, KERN_WARNING
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"sysfs group '%s' not found for kobject '%s'\n",
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grp->name, kobject_name(kobj));
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return;
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}
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} else {
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kn = parent;
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kernfs_get(kn);
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}
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remove_files(kn, grp);
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if (grp->name)
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kernfs_remove(kn);
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kernfs_put(kn);
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}
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EXPORT_SYMBOL_GPL(sysfs_remove_group);
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/**
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* sysfs_remove_groups - remove a list of groups
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*
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* @kobj: The kobject for the groups to be removed from
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* @groups: NULL terminated list of groups to be removed
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*
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* If groups is not NULL, remove the specified groups from the kobject.
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*/
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void sysfs_remove_groups(struct kobject *kobj,
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const struct attribute_group **groups)
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{
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int i;
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if (!groups)
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return;
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for (i = 0; groups[i]; i++)
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sysfs_remove_group(kobj, groups[i]);
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}
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EXPORT_SYMBOL_GPL(sysfs_remove_groups);
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/**
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* sysfs_merge_group - merge files into a pre-existing attribute group.
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* @kobj: The kobject containing the group.
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* @grp: The files to create and the attribute group they belong to.
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*
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* This function returns an error if the group doesn't exist or any of the
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* files already exist in that group, in which case none of the new files
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* are created.
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*/
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int sysfs_merge_group(struct kobject *kobj,
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const struct attribute_group *grp)
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{
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struct kernfs_node *parent;
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kuid_t uid;
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kgid_t gid;
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int error = 0;
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struct attribute *const *attr;
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int i;
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parent = kernfs_find_and_get(kobj->sd, grp->name);
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if (!parent)
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return -ENOENT;
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kobject_get_ownership(kobj, &uid, &gid);
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for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
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error = sysfs_add_file_mode_ns(parent, *attr, false,
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(*attr)->mode, uid, gid, NULL);
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if (error) {
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while (--i >= 0)
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kernfs_remove_by_name(parent, (*--attr)->name);
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}
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kernfs_put(parent);
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return error;
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}
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EXPORT_SYMBOL_GPL(sysfs_merge_group);
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/**
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* sysfs_unmerge_group - remove files from a pre-existing attribute group.
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* @kobj: The kobject containing the group.
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* @grp: The files to remove and the attribute group they belong to.
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*/
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void sysfs_unmerge_group(struct kobject *kobj,
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const struct attribute_group *grp)
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{
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struct kernfs_node *parent;
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struct attribute *const *attr;
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parent = kernfs_find_and_get(kobj->sd, grp->name);
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if (parent) {
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for (attr = grp->attrs; *attr; ++attr)
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kernfs_remove_by_name(parent, (*attr)->name);
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kernfs_put(parent);
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}
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}
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EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
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/**
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* sysfs_add_link_to_group - add a symlink to an attribute group.
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* @kobj: The kobject containing the group.
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* @group_name: The name of the group.
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* @target: The target kobject of the symlink to create.
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* @link_name: The name of the symlink to create.
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*/
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int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
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struct kobject *target, const char *link_name)
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{
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struct kernfs_node *parent;
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int error = 0;
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parent = kernfs_find_and_get(kobj->sd, group_name);
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if (!parent)
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return -ENOENT;
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error = sysfs_create_link_sd(parent, target, link_name);
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kernfs_put(parent);
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return error;
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}
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EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);
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/**
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* sysfs_remove_link_from_group - remove a symlink from an attribute group.
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* @kobj: The kobject containing the group.
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* @group_name: The name of the group.
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* @link_name: The name of the symlink to remove.
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*/
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void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
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const char *link_name)
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{
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struct kernfs_node *parent;
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parent = kernfs_find_and_get(kobj->sd, group_name);
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if (parent) {
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kernfs_remove_by_name(parent, link_name);
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kernfs_put(parent);
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}
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}
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EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
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/**
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* __compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
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* to a group or an attribute
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* @kobj: The kobject containing the group.
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* @target_kobj: The target kobject.
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* @target_name: The name of the target group or attribute.
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*/
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int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
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struct kobject *target_kobj,
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const char *target_name)
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{
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struct kernfs_node *target;
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struct kernfs_node *entry;
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struct kernfs_node *link;
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/*
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* We don't own @target_kobj and it may be removed at any time.
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* Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
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* for details.
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*/
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spin_lock(&sysfs_symlink_target_lock);
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target = target_kobj->sd;
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if (target)
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kernfs_get(target);
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spin_unlock(&sysfs_symlink_target_lock);
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if (!target)
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return -ENOENT;
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entry = kernfs_find_and_get(target_kobj->sd, target_name);
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if (!entry) {
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kernfs_put(target);
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return -ENOENT;
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}
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link = kernfs_create_link(kobj->sd, target_name, entry);
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if (IS_ERR(link) && PTR_ERR(link) == -EEXIST)
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sysfs_warn_dup(kobj->sd, target_name);
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kernfs_put(entry);
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kernfs_put(target);
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return PTR_ERR_OR_ZERO(link);
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}
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EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj);
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