4 * Copyright (C) 2005 Greg Kroah-Hartman <gregkh@suse.de>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License version
8 * 2 as published by the Free Software Foundation.
10 * Based on fs/debugfs/inode.c which had the following copyright notice:
11 * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
12 * Copyright (C) 2004 IBM Inc.
16 #include <linux/module.h>
18 #include <linux/mount.h>
19 #include <linux/pagemap.h>
20 #include <linux/init.h>
21 #include <linux/namei.h>
22 #include <linux/security.h>
23 #include <linux/magic.h>
25 static struct vfsmount *mount;
26 static int mount_count;
28 static inline int positive(struct dentry *dentry)
30 return dentry->d_inode && !d_unhashed(dentry);
33 static int fill_super(struct super_block *sb, void *data, int silent)
35 static struct tree_descr files[] = {{""}};
37 return simple_fill_super(sb, SECURITYFS_MAGIC, files);
40 static struct dentry *get_sb(struct file_system_type *fs_type,
41 int flags, const char *dev_name,
44 return mount_single(fs_type, flags, data, fill_super);
47 static struct file_system_type fs_type = {
51 .kill_sb = kill_litter_super,
55 * securityfs_create_file - create a file in the securityfs filesystem
57 * @name: a pointer to a string containing the name of the file to create.
58 * @mode: the permission that the file should have
59 * @parent: a pointer to the parent dentry for this file. This should be a
60 * directory dentry if set. If this parameter is %NULL, then the
61 * file will be created in the root of the securityfs filesystem.
62 * @data: a pointer to something that the caller will want to get to later
63 * on. The inode.i_private pointer will point to this value on
65 * @fops: a pointer to a struct file_operations that should be used for
68 * This is the basic "create a file" function for securityfs. It allows for a
69 * wide range of flexibility in creating a file, or a directory (if you
70 * want to create a directory, the securityfs_create_dir() function is
71 * recommended to be used instead).
73 * This function returns a pointer to a dentry if it succeeds. This
74 * pointer must be passed to the securityfs_remove() function when the file is
75 * to be removed (no automatic cleanup happens if your module is unloaded,
76 * you are responsible here). If an error occurs, the function will return
77 * the erorr value (via ERR_PTR).
79 * If securityfs is not enabled in the kernel, the value %-ENODEV is
82 struct dentry *securityfs_create_file(const char *name, umode_t mode,
83 struct dentry *parent, void *data,
84 const struct file_operations *fops)
86 struct dentry *dentry;
87 int is_dir = S_ISDIR(mode);
88 struct inode *dir, *inode;
93 mode = (mode & S_IALLUGO) | S_IFREG;
96 pr_debug("securityfs: creating file '%s'\n",name);
98 error = simple_pin_fs(&fs_type, &mount, &mount_count);
100 return ERR_PTR(error);
103 parent = mount->mnt_root;
105 dir = parent->d_inode;
107 mutex_lock(&dir->i_mutex);
108 dentry = lookup_one_len(name, parent, strlen(name));
112 if (dentry->d_inode) {
117 inode = new_inode(dir->i_sb);
123 inode->i_ino = get_next_ino();
124 inode->i_mode = mode;
125 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
126 inode->i_private = data;
128 inode->i_op = &simple_dir_inode_operations;
129 inode->i_fop = &simple_dir_operations;
135 d_instantiate(dentry, inode);
137 mutex_unlock(&dir->i_mutex);
142 dentry = ERR_PTR(error);
144 mutex_unlock(&dir->i_mutex);
145 simple_release_fs(&mount, &mount_count);
148 EXPORT_SYMBOL_GPL(securityfs_create_file);
151 * securityfs_create_dir - create a directory in the securityfs filesystem
153 * @name: a pointer to a string containing the name of the directory to
155 * @parent: a pointer to the parent dentry for this file. This should be a
156 * directory dentry if set. If this parameter is %NULL, then the
157 * directory will be created in the root of the securityfs filesystem.
159 * This function creates a directory in securityfs with the given @name.
161 * This function returns a pointer to a dentry if it succeeds. This
162 * pointer must be passed to the securityfs_remove() function when the file is
163 * to be removed (no automatic cleanup happens if your module is unloaded,
164 * you are responsible here). If an error occurs, %NULL will be returned.
166 * If securityfs is not enabled in the kernel, the value %-ENODEV is
167 * returned. It is not wise to check for this value, but rather, check for
168 * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
171 struct dentry *securityfs_create_dir(const char *name, struct dentry *parent)
173 return securityfs_create_file(name,
174 S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
177 EXPORT_SYMBOL_GPL(securityfs_create_dir);
180 * securityfs_remove - removes a file or directory from the securityfs filesystem
182 * @dentry: a pointer to a the dentry of the file or directory to be removed.
184 * This function removes a file or directory in securityfs that was previously
185 * created with a call to another securityfs function (like
186 * securityfs_create_file() or variants thereof.)
188 * This function is required to be called in order for the file to be
189 * removed. No automatic cleanup of files will happen when a module is
190 * removed; you are responsible here.
192 void securityfs_remove(struct dentry *dentry)
194 struct dentry *parent;
196 if (!dentry || IS_ERR(dentry))
199 parent = dentry->d_parent;
200 if (!parent || !parent->d_inode)
203 mutex_lock(&parent->d_inode->i_mutex);
204 if (positive(dentry)) {
205 if (dentry->d_inode) {
206 if (S_ISDIR(dentry->d_inode->i_mode))
207 simple_rmdir(parent->d_inode, dentry);
209 simple_unlink(parent->d_inode, dentry);
213 mutex_unlock(&parent->d_inode->i_mutex);
214 simple_release_fs(&mount, &mount_count);
216 EXPORT_SYMBOL_GPL(securityfs_remove);
218 static struct kobject *security_kobj;
220 static int __init securityfs_init(void)
224 security_kobj = kobject_create_and_add("security", kernel_kobj);
228 retval = register_filesystem(&fs_type);
230 kobject_put(security_kobj);
234 core_initcall(securityfs_init);
235 MODULE_LICENSE("GPL");