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Greg Kroah-Hartman619daee2018-01-22 16:18:13 +01001// SPDX-License-Identifier: GPL-2.0
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
Tejun Heo6d66f5c2007-09-20 17:31:38 +09003 * fs/sysfs/dir.c - sysfs core and dir operation implementation
4 *
5 * Copyright (c) 2001-3 Patrick Mochel
6 * Copyright (c) 2007 SUSE Linux Products GmbH
7 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
8 *
Mauro Carvalho Chehab0c1bc6b2020-04-14 18:48:37 +02009 * Please see Documentation/filesystems/sysfs.rst for more information.
Linus Torvalds1da177e2005-04-16 15:20:36 -070010 */
11
Greg Kroah-Hartman5d54f942018-01-22 15:57:59 +010012#define pr_fmt(fmt) "sysfs: " fmt
Linus Torvalds1da177e2005-04-16 15:20:36 -070013
14#include <linux/fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/kobject.h>
Robert P. J. Dayc6f87732008-03-13 22:41:52 -040016#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include "sysfs.h"
18
Tejun Heo0cae60f2013-10-30 10:28:36 -040019DEFINE_SPINLOCK(sysfs_symlink_target_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070020
Tejun Heo324a56e2013-12-11 14:11:53 -050021void sysfs_warn_dup(struct kernfs_node *parent, const char *name)
Tejun Heod1c14592013-10-24 11:49:11 -040022{
Tejun Heo3abb1d92016-08-10 11:23:44 -040023 char *buf;
Tejun Heod1c14592013-10-24 11:49:11 -040024
Tejun Heo3eef34a2014-02-07 13:32:07 -050025 buf = kzalloc(PATH_MAX, GFP_KERNEL);
26 if (buf)
Tejun Heo3abb1d92016-08-10 11:23:44 -040027 kernfs_path(parent, buf, PATH_MAX);
Tejun Heod1c14592013-10-24 11:49:11 -040028
Greg Kroah-Hartman5d54f942018-01-22 15:57:59 +010029 pr_warn("cannot create duplicate filename '%s/%s'\n", buf, name);
30 dump_stack();
Tejun Heod1c14592013-10-24 11:49:11 -040031
Tejun Heo3eef34a2014-02-07 13:32:07 -050032 kfree(buf);
Tejun Heod1c14592013-10-24 11:49:11 -040033}
34
Alex Chiang425cb022009-02-12 10:56:59 -070035/**
Tejun Heoe34ff492013-09-11 22:29:05 -040036 * sysfs_create_dir_ns - create a directory for an object with a namespace tag
37 * @kobj: object we're creating directory for
38 * @ns: the namespace tag to use
Linus Torvalds1da177e2005-04-16 15:20:36 -070039 */
Tejun Heoe34ff492013-09-11 22:29:05 -040040int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
Linus Torvalds1da177e2005-04-16 15:20:36 -070041{
Tejun Heo324a56e2013-12-11 14:11:53 -050042 struct kernfs_node *parent, *kn;
Dmitry Torokhov5f818802018-07-20 21:56:48 +000043 kuid_t uid;
44 kgid_t gid;
Linus Torvalds1da177e2005-04-16 15:20:36 -070045
Greg Kroah-Hartmande96e9f2019-01-03 10:23:47 +010046 if (WARN_ON(!kobj))
47 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -070048
Eric W. Biederman90bc6132007-07-31 19:15:08 +090049 if (kobj->parent)
Tejun Heo324a56e2013-12-11 14:11:53 -050050 parent = kobj->parent->sd;
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 else
Tejun Heo324a56e2013-12-11 14:11:53 -050052 parent = sysfs_root_kn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
Tejun Heo324a56e2013-12-11 14:11:53 -050054 if (!parent)
Dan Williams3a198882012-04-06 13:41:06 -070055 return -ENOENT;
56
Dmitry Torokhov5f818802018-07-20 21:56:48 +000057 kobject_get_ownership(kobj, &uid, &gid);
58
Luis Chamberlaind7c5bf92021-09-27 09:38:01 -070059 kn = kernfs_create_dir_ns(parent, kobject_name(kobj), 0755, uid, gid,
Dmitry Torokhov488dee92018-07-20 21:56:47 +000060 kobj, ns);
Tejun Heo324a56e2013-12-11 14:11:53 -050061 if (IS_ERR(kn)) {
62 if (PTR_ERR(kn) == -EEXIST)
63 sysfs_warn_dup(parent, kobject_name(kobj));
64 return PTR_ERR(kn);
Tejun Heo93b2b8e2013-11-28 14:54:15 -050065 }
66
Tejun Heo324a56e2013-12-11 14:11:53 -050067 kobj->sd = kn;
Tejun Heo93b2b8e2013-11-28 14:54:15 -050068 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070069}
70
Tejun Heo7eed6ec2013-10-24 11:49:10 -040071/**
Eric W. Biedermanb592fcf2007-01-24 12:35:52 -070072 * sysfs_remove_dir - remove an object's directory.
73 * @kobj: object.
74 *
75 * The only thing special about this is that we remove any files in
76 * the directory before we remove the directory, and we've inlined
77 * what used to be sysfs_rmdir() below, instead of calling separately.
78 */
Greg Kroah-Hartman1b18dc22013-08-21 16:28:26 -070079void sysfs_remove_dir(struct kobject *kobj)
Eric W. Biedermanb592fcf2007-01-24 12:35:52 -070080{
Tejun Heo324a56e2013-12-11 14:11:53 -050081 struct kernfs_node *kn = kobj->sd;
Tejun Heoaecdced2007-06-14 03:45:15 +090082
Tejun Heo0cae60f2013-10-30 10:28:36 -040083 /*
84 * In general, kboject owner is responsible for ensuring removal
85 * doesn't race with other operations and sysfs doesn't provide any
86 * protection; however, when @kobj is used as a symlink target, the
87 * symlinking entity usually doesn't own @kobj and thus has no
Tejun Heo324a56e2013-12-11 14:11:53 -050088 * control over removal. @kobj->sd may be removed anytime
89 * and symlink code may end up dereferencing an already freed node.
Tejun Heo0cae60f2013-10-30 10:28:36 -040090 *
Tejun Heo324a56e2013-12-11 14:11:53 -050091 * sysfs_symlink_target_lock synchronizes @kobj->sd
92 * disassociation against symlink operations so that symlink code
93 * can safely dereference @kobj->sd.
Tejun Heo0cae60f2013-10-30 10:28:36 -040094 */
95 spin_lock(&sysfs_symlink_target_lock);
Tejun Heo608e2662007-06-14 04:27:22 +090096 kobj->sd = NULL;
Tejun Heo0cae60f2013-10-30 10:28:36 -040097 spin_unlock(&sysfs_symlink_target_lock);
Tejun Heoaecdced2007-06-14 03:45:15 +090098
Tejun Heo324a56e2013-12-11 14:11:53 -050099 if (kn) {
Tejun Heodf23fc32013-12-11 14:11:56 -0500100 WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR);
Tejun Heo324a56e2013-12-11 14:11:53 -0500101 kernfs_remove(kn);
Tejun Heo250f7c32013-09-18 17:15:38 -0400102 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103}
104
Tejun Heoe34ff492013-09-11 22:29:05 -0400105int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
106 const void *new_ns)
Eric W. Biedermanca1bab32009-11-20 16:08:57 -0800107{
Tejun Heo3eef34a2014-02-07 13:32:07 -0500108 struct kernfs_node *parent;
109 int ret;
Eric W. Biederman3ff195b2010-03-30 11:31:26 -0700110
Tejun Heo3eef34a2014-02-07 13:32:07 -0500111 parent = kernfs_get_parent(kobj->sd);
112 ret = kernfs_rename_ns(kobj->sd, parent, new_name, new_ns);
113 kernfs_put(parent);
114 return ret;
Eric W. Biedermanca1bab32009-11-20 16:08:57 -0800115}
116
Tejun Heoe34ff492013-09-11 22:29:05 -0400117int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
118 const void *new_ns)
Cornelia Huck8a824722006-11-20 17:07:51 +0100119{
Tejun Heo324a56e2013-12-11 14:11:53 -0500120 struct kernfs_node *kn = kobj->sd;
121 struct kernfs_node *new_parent;
Cornelia Huck8a824722006-11-20 17:07:51 +0100122
Tejun Heo324a56e2013-12-11 14:11:53 -0500123 new_parent = new_parent_kobj && new_parent_kobj->sd ?
124 new_parent_kobj->sd : sysfs_root_kn;
Cornelia Huck8a824722006-11-20 17:07:51 +0100125
Tejun Heoadc5e8b2013-12-11 14:11:54 -0500126 return kernfs_rename_ns(kn, new_parent, kn->name, new_ns);
Cornelia Huck8a824722006-11-20 17:07:51 +0100127}
Eric W. Biederman87d28462015-05-13 16:31:40 -0500128
129/**
130 * sysfs_create_mount_point - create an always empty directory
131 * @parent_kobj: kobject that will contain this always empty directory
132 * @name: The name of the always empty directory to add
133 */
134int sysfs_create_mount_point(struct kobject *parent_kobj, const char *name)
135{
136 struct kernfs_node *kn, *parent = parent_kobj->sd;
137
138 kn = kernfs_create_empty_dir(parent, name);
139 if (IS_ERR(kn)) {
140 if (PTR_ERR(kn) == -EEXIST)
141 sysfs_warn_dup(parent, name);
142 return PTR_ERR(kn);
143 }
144
145 return 0;
146}
147EXPORT_SYMBOL_GPL(sysfs_create_mount_point);
148
149/**
150 * sysfs_remove_mount_point - remove an always empty directory.
151 * @parent_kobj: kobject that will contain this always empty directory
152 * @name: The name of the always empty directory to remove
153 *
154 */
155void sysfs_remove_mount_point(struct kobject *parent_kobj, const char *name)
156{
157 struct kernfs_node *parent = parent_kobj->sd;
158
159 kernfs_remove_by_name_ns(parent, name, NULL);
160}
161EXPORT_SYMBOL_GPL(sysfs_remove_mount_point);