162 lines
4.1 KiB
C
162 lines
4.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* fs/sysfs/dir.c - sysfs core and dir operation implementation
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*
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* Copyright (c) 2001-3 Patrick Mochel
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* Copyright (c) 2007 SUSE Linux Products GmbH
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* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
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*
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* Please see Documentation/filesystems/sysfs.txt for more information.
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*/
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#define pr_fmt(fmt) "sysfs: " fmt
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#include <linux/fs.h>
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#include <linux/kobject.h>
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#include <linux/slab.h>
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#include "sysfs.h"
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DEFINE_SPINLOCK(sysfs_symlink_target_lock);
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void sysfs_warn_dup(struct kernfs_node *parent, const char *name)
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{
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char *buf;
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buf = kzalloc(PATH_MAX, GFP_KERNEL);
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if (buf)
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kernfs_path(parent, buf, PATH_MAX);
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pr_warn("cannot create duplicate filename '%s/%s'\n", buf, name);
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dump_stack();
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kfree(buf);
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}
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/**
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* sysfs_create_dir_ns - create a directory for an object with a namespace tag
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* @kobj: object we're creating directory for
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* @ns: the namespace tag to use
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*/
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int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
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{
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struct kernfs_node *parent, *kn;
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kuid_t uid;
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kgid_t gid;
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BUG_ON(!kobj);
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if (kobj->parent)
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parent = kobj->parent->sd;
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else
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parent = sysfs_root_kn;
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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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kn = kernfs_create_dir_ns(parent, kobject_name(kobj),
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S_IRWXU | S_IRUGO | S_IXUGO, uid, gid,
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kobj, ns);
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if (IS_ERR(kn)) {
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if (PTR_ERR(kn) == -EEXIST)
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sysfs_warn_dup(parent, kobject_name(kobj));
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return PTR_ERR(kn);
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}
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kobj->sd = kn;
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return 0;
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}
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/**
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* sysfs_remove_dir - remove an object's directory.
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* @kobj: object.
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*
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* The only thing special about this is that we remove any files in
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* the directory before we remove the directory, and we've inlined
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* what used to be sysfs_rmdir() below, instead of calling separately.
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*/
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void sysfs_remove_dir(struct kobject *kobj)
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{
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struct kernfs_node *kn = kobj->sd;
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/*
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* In general, kboject owner is responsible for ensuring removal
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* doesn't race with other operations and sysfs doesn't provide any
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* protection; however, when @kobj is used as a symlink target, the
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* symlinking entity usually doesn't own @kobj and thus has no
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* control over removal. @kobj->sd may be removed anytime
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* and symlink code may end up dereferencing an already freed node.
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*
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* sysfs_symlink_target_lock synchronizes @kobj->sd
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* disassociation against symlink operations so that symlink code
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* can safely dereference @kobj->sd.
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*/
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spin_lock(&sysfs_symlink_target_lock);
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kobj->sd = NULL;
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spin_unlock(&sysfs_symlink_target_lock);
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if (kn) {
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WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR);
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kernfs_remove(kn);
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}
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}
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int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
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const void *new_ns)
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{
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struct kernfs_node *parent;
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int ret;
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parent = kernfs_get_parent(kobj->sd);
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ret = kernfs_rename_ns(kobj->sd, parent, new_name, new_ns);
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kernfs_put(parent);
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return ret;
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}
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int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
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const void *new_ns)
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{
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struct kernfs_node *kn = kobj->sd;
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struct kernfs_node *new_parent;
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new_parent = new_parent_kobj && new_parent_kobj->sd ?
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new_parent_kobj->sd : sysfs_root_kn;
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return kernfs_rename_ns(kn, new_parent, kn->name, new_ns);
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}
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/**
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* sysfs_create_mount_point - create an always empty directory
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* @parent_kobj: kobject that will contain this always empty directory
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* @name: The name of the always empty directory to add
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*/
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int sysfs_create_mount_point(struct kobject *parent_kobj, const char *name)
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{
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struct kernfs_node *kn, *parent = parent_kobj->sd;
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kn = kernfs_create_empty_dir(parent, name);
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if (IS_ERR(kn)) {
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if (PTR_ERR(kn) == -EEXIST)
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sysfs_warn_dup(parent, name);
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return PTR_ERR(kn);
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(sysfs_create_mount_point);
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/**
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* sysfs_remove_mount_point - remove an always empty directory.
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* @parent_kobj: kobject that will contain this always empty directory
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* @name: The name of the always empty directory to remove
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*
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*/
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void sysfs_remove_mount_point(struct kobject *parent_kobj, const char *name)
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{
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struct kernfs_node *parent = parent_kobj->sd;
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kernfs_remove_by_name_ns(parent, name, NULL);
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}
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EXPORT_SYMBOL_GPL(sysfs_remove_mount_point);
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