2 * fs/sysfs/dir.c - sysfs core and dir operation implementation
4 * Copyright (c) 2001-3 Patrick Mochel
5 * Copyright (c) 2007 SUSE Linux Products GmbH
6 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
8 * This file is released under the GPLv2.
10 * Please see Documentation/filesystems/sysfs.txt for more information.
16 #include <linux/kobject.h>
17 #include <linux/slab.h>
20 DEFINE_SPINLOCK(sysfs_symlink_target_lock);
23 * sysfs_pathname - return full path to sysfs dirent
24 * @kn: kernfs_node whose path we want
25 * @path: caller allocated buffer of size PATH_MAX
27 * Gives the name "/" to the sysfs_root entry; any path returned
28 * is relative to wherever sysfs is mounted.
30 static char *sysfs_pathname(struct kernfs_node *kn, char *path)
33 sysfs_pathname(kn->parent, path);
34 strlcat(path, "/", PATH_MAX);
36 strlcat(path, kn->name, PATH_MAX);
40 void sysfs_warn_dup(struct kernfs_node *parent, const char *name)
44 path = kzalloc(PATH_MAX, GFP_KERNEL);
46 sysfs_pathname(parent, path);
47 strlcat(path, "/", PATH_MAX);
48 strlcat(path, name, PATH_MAX);
51 WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s'\n",
58 * sysfs_create_dir_ns - create a directory for an object with a namespace tag
59 * @kobj: object we're creating directory for
60 * @ns: the namespace tag to use
62 int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
64 struct kernfs_node *parent, *kn;
69 parent = kobj->parent->sd;
71 parent = sysfs_root_kn;
76 kn = kernfs_create_dir_ns(parent, kobject_name(kobj),
77 S_IRWXU | S_IRUGO | S_IXUGO, kobj, ns);
79 if (PTR_ERR(kn) == -EEXIST)
80 sysfs_warn_dup(parent, kobject_name(kobj));
89 * sysfs_remove_dir - remove an object's directory.
92 * The only thing special about this is that we remove any files in
93 * the directory before we remove the directory, and we've inlined
94 * what used to be sysfs_rmdir() below, instead of calling separately.
96 void sysfs_remove_dir(struct kobject *kobj)
98 struct kernfs_node *kn = kobj->sd;
101 * In general, kboject owner is responsible for ensuring removal
102 * doesn't race with other operations and sysfs doesn't provide any
103 * protection; however, when @kobj is used as a symlink target, the
104 * symlinking entity usually doesn't own @kobj and thus has no
105 * control over removal. @kobj->sd may be removed anytime
106 * and symlink code may end up dereferencing an already freed node.
108 * sysfs_symlink_target_lock synchronizes @kobj->sd
109 * disassociation against symlink operations so that symlink code
110 * can safely dereference @kobj->sd.
112 spin_lock(&sysfs_symlink_target_lock);
114 spin_unlock(&sysfs_symlink_target_lock);
117 WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR);
122 int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
125 struct kernfs_node *parent = kobj->sd->parent;
127 return kernfs_rename_ns(kobj->sd, parent, new_name, new_ns);
130 int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
133 struct kernfs_node *kn = kobj->sd;
134 struct kernfs_node *new_parent;
137 new_parent = new_parent_kobj && new_parent_kobj->sd ?
138 new_parent_kobj->sd : sysfs_root_kn;
140 return kernfs_rename_ns(kn, new_parent, kn->name, new_ns);