ia64/linux-2.6.18-xen.hg

view security/inode.c @ 749:2892ca2b9c17

linux/x86: cleanup IO-APIC code

- get 32-bit code in sync with 64-bit wrt ExtINT pin detection being
unnecessary
- eliminate build warnings resulting from c/s 725

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Fri Nov 28 13:31:21 2008 +0000 (2008-11-28)
parents 831230e53067
children
line source
1 /*
2 * inode.c - securityfs
3 *
4 * Copyright (C) 2005 Greg Kroah-Hartman <gregkh@suse.de>
5 *
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.
9 *
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.
13 */
15 /* #define DEBUG */
16 #include <linux/module.h>
17 #include <linux/fs.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>
24 #define SECURITYFS_MAGIC 0x73636673
26 static struct vfsmount *mount;
27 static int mount_count;
29 /*
30 * TODO:
31 * I think I can get rid of these default_file_ops, but not quite sure...
32 */
33 static ssize_t default_read_file(struct file *file, char __user *buf,
34 size_t count, loff_t *ppos)
35 {
36 return 0;
37 }
39 static ssize_t default_write_file(struct file *file, const char __user *buf,
40 size_t count, loff_t *ppos)
41 {
42 return count;
43 }
45 static int default_open(struct inode *inode, struct file *file)
46 {
47 if (inode->u.generic_ip)
48 file->private_data = inode->u.generic_ip;
50 return 0;
51 }
53 static struct file_operations default_file_ops = {
54 .read = default_read_file,
55 .write = default_write_file,
56 .open = default_open,
57 };
59 static struct inode *get_inode(struct super_block *sb, int mode, dev_t dev)
60 {
61 struct inode *inode = new_inode(sb);
63 if (inode) {
64 inode->i_mode = mode;
65 inode->i_uid = 0;
66 inode->i_gid = 0;
67 inode->i_blksize = PAGE_CACHE_SIZE;
68 inode->i_blocks = 0;
69 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
70 switch (mode & S_IFMT) {
71 default:
72 init_special_inode(inode, mode, dev);
73 break;
74 case S_IFREG:
75 inode->i_fop = &default_file_ops;
76 break;
77 case S_IFDIR:
78 inode->i_op = &simple_dir_inode_operations;
79 inode->i_fop = &simple_dir_operations;
81 /* directory inodes start off with i_nlink == 2 (for "." entry) */
82 inode->i_nlink++;
83 break;
84 }
85 }
86 return inode;
87 }
89 /* SMP-safe */
90 static int mknod(struct inode *dir, struct dentry *dentry,
91 int mode, dev_t dev)
92 {
93 struct inode *inode;
94 int error = -EPERM;
96 if (dentry->d_inode)
97 return -EEXIST;
99 inode = get_inode(dir->i_sb, mode, dev);
100 if (inode) {
101 d_instantiate(dentry, inode);
102 dget(dentry);
103 error = 0;
104 }
105 return error;
106 }
108 static int mkdir(struct inode *dir, struct dentry *dentry, int mode)
109 {
110 int res;
112 mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
113 res = mknod(dir, dentry, mode, 0);
114 if (!res)
115 dir->i_nlink++;
116 return res;
117 }
119 static int create(struct inode *dir, struct dentry *dentry, int mode)
120 {
121 mode = (mode & S_IALLUGO) | S_IFREG;
122 return mknod(dir, dentry, mode, 0);
123 }
125 static inline int positive(struct dentry *dentry)
126 {
127 return dentry->d_inode && !d_unhashed(dentry);
128 }
130 static int fill_super(struct super_block *sb, void *data, int silent)
131 {
132 static struct tree_descr files[] = {{""}};
134 return simple_fill_super(sb, SECURITYFS_MAGIC, files);
135 }
137 static int get_sb(struct file_system_type *fs_type,
138 int flags, const char *dev_name,
139 void *data, struct vfsmount *mnt)
140 {
141 return get_sb_single(fs_type, flags, data, fill_super, mnt);
142 }
144 static struct file_system_type fs_type = {
145 .owner = THIS_MODULE,
146 .name = "securityfs",
147 .get_sb = get_sb,
148 .kill_sb = kill_litter_super,
149 };
151 static int create_by_name(const char *name, mode_t mode,
152 struct dentry *parent,
153 struct dentry **dentry)
154 {
155 int error = 0;
157 *dentry = NULL;
159 /* If the parent is not specified, we create it in the root.
160 * We need the root dentry to do this, which is in the super
161 * block. A pointer to that is in the struct vfsmount that we
162 * have around.
163 */
164 if (!parent ) {
165 if (mount && mount->mnt_sb) {
166 parent = mount->mnt_sb->s_root;
167 }
168 }
169 if (!parent) {
170 pr_debug("securityfs: Ah! can not find a parent!\n");
171 return -EFAULT;
172 }
174 mutex_lock(&parent->d_inode->i_mutex);
175 *dentry = lookup_one_len(name, parent, strlen(name));
176 if (!IS_ERR(dentry)) {
177 if ((mode & S_IFMT) == S_IFDIR)
178 error = mkdir(parent->d_inode, *dentry, mode);
179 else
180 error = create(parent->d_inode, *dentry, mode);
181 } else
182 error = PTR_ERR(dentry);
183 mutex_unlock(&parent->d_inode->i_mutex);
185 return error;
186 }
188 /**
189 * securityfs_create_file - create a file in the securityfs filesystem
190 *
191 * @name: a pointer to a string containing the name of the file to create.
192 * @mode: the permission that the file should have
193 * @parent: a pointer to the parent dentry for this file. This should be a
194 * directory dentry if set. If this paramater is NULL, then the
195 * file will be created in the root of the securityfs filesystem.
196 * @data: a pointer to something that the caller will want to get to later
197 * on. The inode.u.generic_ip pointer will point to this value on
198 * the open() call.
199 * @fops: a pointer to a struct file_operations that should be used for
200 * this file.
201 *
202 * This is the basic "create a file" function for securityfs. It allows for a
203 * wide range of flexibility in createing a file, or a directory (if you
204 * want to create a directory, the securityfs_create_dir() function is
205 * recommended to be used instead.)
206 *
207 * This function will return a pointer to a dentry if it succeeds. This
208 * pointer must be passed to the securityfs_remove() function when the file is
209 * to be removed (no automatic cleanup happens if your module is unloaded,
210 * you are responsible here.) If an error occurs, NULL will be returned.
211 *
212 * If securityfs is not enabled in the kernel, the value -ENODEV will be
213 * returned. It is not wise to check for this value, but rather, check for
214 * NULL or !NULL instead as to eliminate the need for #ifdef in the calling
215 * code.
216 */
217 struct dentry *securityfs_create_file(const char *name, mode_t mode,
218 struct dentry *parent, void *data,
219 struct file_operations *fops)
220 {
221 struct dentry *dentry = NULL;
222 int error;
224 pr_debug("securityfs: creating file '%s'\n",name);
226 error = simple_pin_fs(&fs_type, &mount, &mount_count);
227 if (error) {
228 dentry = ERR_PTR(error);
229 goto exit;
230 }
232 error = create_by_name(name, mode, parent, &dentry);
233 if (error) {
234 dentry = ERR_PTR(error);
235 simple_release_fs(&mount, &mount_count);
236 goto exit;
237 }
239 if (dentry->d_inode) {
240 if (fops)
241 dentry->d_inode->i_fop = fops;
242 if (data)
243 dentry->d_inode->u.generic_ip = data;
244 }
245 exit:
246 return dentry;
247 }
248 EXPORT_SYMBOL_GPL(securityfs_create_file);
250 /**
251 * securityfs_create_dir - create a directory in the securityfs filesystem
252 *
253 * @name: a pointer to a string containing the name of the directory to
254 * create.
255 * @parent: a pointer to the parent dentry for this file. This should be a
256 * directory dentry if set. If this paramater is NULL, then the
257 * directory will be created in the root of the securityfs filesystem.
258 *
259 * This function creates a directory in securityfs with the given name.
260 *
261 * This function will return a pointer to a dentry if it succeeds. This
262 * pointer must be passed to the securityfs_remove() function when the file is
263 * to be removed (no automatic cleanup happens if your module is unloaded,
264 * you are responsible here.) If an error occurs, NULL will be returned.
265 *
266 * If securityfs is not enabled in the kernel, the value -ENODEV will be
267 * returned. It is not wise to check for this value, but rather, check for
268 * NULL or !NULL instead as to eliminate the need for #ifdef in the calling
269 * code.
270 */
271 struct dentry *securityfs_create_dir(const char *name, struct dentry *parent)
272 {
273 return securityfs_create_file(name,
274 S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
275 parent, NULL, NULL);
276 }
277 EXPORT_SYMBOL_GPL(securityfs_create_dir);
279 /**
280 * securityfs_remove - removes a file or directory from the securityfs filesystem
281 *
282 * @dentry: a pointer to a the dentry of the file or directory to be
283 * removed.
284 *
285 * This function removes a file or directory in securityfs that was previously
286 * created with a call to another securityfs function (like
287 * securityfs_create_file() or variants thereof.)
288 *
289 * This function is required to be called in order for the file to be
290 * removed, no automatic cleanup of files will happen when a module is
291 * removed, you are responsible here.
292 */
293 void securityfs_remove(struct dentry *dentry)
294 {
295 struct dentry *parent;
297 if (!dentry)
298 return;
300 parent = dentry->d_parent;
301 if (!parent || !parent->d_inode)
302 return;
304 mutex_lock(&parent->d_inode->i_mutex);
305 if (positive(dentry)) {
306 if (dentry->d_inode) {
307 if (S_ISDIR(dentry->d_inode->i_mode))
308 simple_rmdir(parent->d_inode, dentry);
309 else
310 simple_unlink(parent->d_inode, dentry);
311 dput(dentry);
312 }
313 }
314 mutex_unlock(&parent->d_inode->i_mutex);
315 simple_release_fs(&mount, &mount_count);
316 }
317 EXPORT_SYMBOL_GPL(securityfs_remove);
319 static decl_subsys(security, NULL, NULL);
321 static int __init securityfs_init(void)
322 {
323 int retval;
325 kset_set_kset_s(&security_subsys, kernel_subsys);
326 retval = subsystem_register(&security_subsys);
327 if (retval)
328 return retval;
330 retval = register_filesystem(&fs_type);
331 if (retval)
332 subsystem_unregister(&security_subsys);
333 return retval;
334 }
336 static void __exit securityfs_exit(void)
337 {
338 simple_release_fs(&mount, &mount_count);
339 unregister_filesystem(&fs_type);
340 subsystem_unregister(&security_subsys);
341 }
343 core_initcall(securityfs_init);
344 module_exit(securityfs_exit);
345 MODULE_LICENSE("GPL");