Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
6d66f5cd | 2 | * fs/sysfs/inode.c - basic sysfs inode and dentry operations |
1da177e4 | 3 | * |
6d66f5cd TH |
4 | * Copyright (c) 2001-3 Patrick Mochel |
5 | * Copyright (c) 2007 SUSE Linux Products GmbH | |
6 | * Copyright (c) 2007 Tejun Heo <teheo@suse.de> | |
7 | * | |
8 | * This file is released under the GPLv2. | |
1da177e4 LT |
9 | * |
10 | * Please see Documentation/filesystems/sysfs.txt for more information. | |
11 | */ | |
12 | ||
13 | #undef DEBUG | |
14 | ||
15 | #include <linux/pagemap.h> | |
16 | #include <linux/namei.h> | |
17 | #include <linux/backing-dev.h> | |
16f7e0fe | 18 | #include <linux/capability.h> |
995982ca | 19 | #include <linux/errno.h> |
e8edc6e0 | 20 | #include <linux/sched.h> |
5a0e3ad6 | 21 | #include <linux/slab.h> |
57cc7215 | 22 | #include <linux/sysfs.h> |
ddd29ec6 DQ |
23 | #include <linux/xattr.h> |
24 | #include <linux/security.h> | |
1da177e4 LT |
25 | #include "sysfs.h" |
26 | ||
27 | extern struct super_block * sysfs_sb; | |
28 | ||
f5e54d6e | 29 | static const struct address_space_operations sysfs_aops = { |
1da177e4 | 30 | .readpage = simple_readpage, |
800d15a5 NP |
31 | .write_begin = simple_write_begin, |
32 | .write_end = simple_write_end, | |
1da177e4 LT |
33 | }; |
34 | ||
35 | static struct backing_dev_info sysfs_backing_dev_info = { | |
d993831f | 36 | .name = "sysfs", |
1da177e4 | 37 | .ra_pages = 0, /* No readahead */ |
e4ad08fe | 38 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, |
1da177e4 LT |
39 | }; |
40 | ||
c5ef1c42 | 41 | static const struct inode_operations sysfs_inode_operations ={ |
e61ab4ae | 42 | .permission = sysfs_permission, |
988d186d | 43 | .setattr = sysfs_setattr, |
e61ab4ae | 44 | .getattr = sysfs_getattr, |
ddd29ec6 | 45 | .setxattr = sysfs_setxattr, |
988d186d MS |
46 | }; |
47 | ||
e0bf68dd PZ |
48 | int __init sysfs_inode_init(void) |
49 | { | |
50 | return bdi_init(&sysfs_backing_dev_info); | |
51 | } | |
52 | ||
f38506c4 | 53 | static struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd) |
ddd29ec6 DQ |
54 | { |
55 | struct sysfs_inode_attrs *attrs; | |
56 | struct iattr *iattrs; | |
57 | ||
58 | attrs = kzalloc(sizeof(struct sysfs_inode_attrs), GFP_KERNEL); | |
59 | if (!attrs) | |
60 | return NULL; | |
61 | iattrs = &attrs->ia_iattr; | |
62 | ||
63 | /* assign default attributes */ | |
64 | iattrs->ia_mode = sd->s_mode; | |
ab27b91b EB |
65 | iattrs->ia_uid = GLOBAL_ROOT_UID; |
66 | iattrs->ia_gid = GLOBAL_ROOT_GID; | |
ddd29ec6 DQ |
67 | iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME; |
68 | ||
69 | return attrs; | |
70 | } | |
f38506c4 | 71 | |
35df63c4 | 72 | int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr * iattr) |
988d186d | 73 | { |
ddd29ec6 DQ |
74 | struct sysfs_inode_attrs *sd_attrs; |
75 | struct iattr *iattrs; | |
988d186d | 76 | unsigned int ia_valid = iattr->ia_valid; |
988d186d | 77 | |
ddd29ec6 | 78 | sd_attrs = sd->s_iattr; |
988d186d | 79 | |
ddd29ec6 | 80 | if (!sd_attrs) { |
988d186d | 81 | /* setting attributes for the first time, allocate now */ |
ddd29ec6 DQ |
82 | sd_attrs = sysfs_init_inode_attrs(sd); |
83 | if (!sd_attrs) | |
988d186d | 84 | return -ENOMEM; |
ddd29ec6 | 85 | sd->s_iattr = sd_attrs; |
7c0ff870 EB |
86 | } |
87 | /* attributes were changed at least once in past */ | |
88 | iattrs = &sd_attrs->ia_iattr; | |
89 | ||
90 | if (ia_valid & ATTR_UID) | |
91 | iattrs->ia_uid = iattr->ia_uid; | |
92 | if (ia_valid & ATTR_GID) | |
93 | iattrs->ia_gid = iattr->ia_gid; | |
94 | if (ia_valid & ATTR_ATIME) | |
95 | iattrs->ia_atime = iattr->ia_atime; | |
96 | if (ia_valid & ATTR_MTIME) | |
97 | iattrs->ia_mtime = iattr->ia_mtime; | |
98 | if (ia_valid & ATTR_CTIME) | |
99 | iattrs->ia_ctime = iattr->ia_ctime; | |
100 | if (ia_valid & ATTR_MODE) { | |
101 | umode_t mode = iattr->ia_mode; | |
102 | iattrs->ia_mode = sd->s_mode = mode; | |
988d186d | 103 | } |
35df63c4 EB |
104 | return 0; |
105 | } | |
106 | ||
107 | int sysfs_setattr(struct dentry *dentry, struct iattr *iattr) | |
108 | { | |
109 | struct inode *inode = dentry->d_inode; | |
110 | struct sysfs_dirent *sd = dentry->d_fsdata; | |
111 | int error; | |
112 | ||
113 | if (!sd) | |
114 | return -EINVAL; | |
115 | ||
f8d4f618 | 116 | mutex_lock(&sysfs_mutex); |
35df63c4 EB |
117 | error = inode_change_ok(inode, iattr); |
118 | if (error) | |
f8d4f618 | 119 | goto out; |
35df63c4 | 120 | |
75de46b9 NP |
121 | error = sysfs_sd_setattr(sd, iattr); |
122 | if (error) | |
123 | goto out; | |
124 | ||
3322e79a | 125 | /* this ignores size changes */ |
6a1a90ad | 126 | setattr_copy(inode, iattr); |
35df63c4 | 127 | |
f8d4f618 | 128 | out: |
35df63c4 | 129 | mutex_unlock(&sysfs_mutex); |
ddd29ec6 DQ |
130 | return error; |
131 | } | |
988d186d | 132 | |
f44d3e78 EB |
133 | static int sysfs_sd_setsecdata(struct sysfs_dirent *sd, void **secdata, u32 *secdata_len) |
134 | { | |
135 | struct sysfs_inode_attrs *iattrs; | |
136 | void *old_secdata; | |
137 | size_t old_secdata_len; | |
138 | ||
93518dd2 MI |
139 | if (!sd->s_iattr) { |
140 | sd->s_iattr = sysfs_init_inode_attrs(sd); | |
141 | if (!sd->s_iattr) | |
142 | return -ENOMEM; | |
143 | } | |
f44d3e78 | 144 | |
93518dd2 | 145 | iattrs = sd->s_iattr; |
f44d3e78 EB |
146 | old_secdata = iattrs->ia_secdata; |
147 | old_secdata_len = iattrs->ia_secdata_len; | |
148 | ||
149 | iattrs->ia_secdata = *secdata; | |
150 | iattrs->ia_secdata_len = *secdata_len; | |
151 | ||
152 | *secdata = old_secdata; | |
153 | *secdata_len = old_secdata_len; | |
154 | return 0; | |
155 | } | |
156 | ||
ddd29ec6 DQ |
157 | int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value, |
158 | size_t size, int flags) | |
159 | { | |
160 | struct sysfs_dirent *sd = dentry->d_fsdata; | |
ddd29ec6 DQ |
161 | void *secdata; |
162 | int error; | |
163 | u32 secdata_len = 0; | |
164 | ||
165 | if (!sd) | |
166 | return -EINVAL; | |
ddd29ec6 DQ |
167 | |
168 | if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) { | |
169 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; | |
170 | error = security_inode_setsecurity(dentry->d_inode, suffix, | |
171 | value, size, flags); | |
172 | if (error) | |
173 | goto out; | |
174 | error = security_inode_getsecctx(dentry->d_inode, | |
175 | &secdata, &secdata_len); | |
176 | if (error) | |
177 | goto out; | |
988d186d | 178 | |
f44d3e78 EB |
179 | mutex_lock(&sysfs_mutex); |
180 | error = sysfs_sd_setsecdata(sd, &secdata, &secdata_len); | |
181 | mutex_unlock(&sysfs_mutex); | |
182 | ||
183 | if (secdata) | |
184 | security_release_secctx(secdata, secdata_len); | |
ddd29ec6 DQ |
185 | } else |
186 | return -EINVAL; | |
187 | out: | |
988d186d MS |
188 | return error; |
189 | } | |
190 | ||
faef2b6c | 191 | static inline void set_default_inode_attr(struct inode * inode, umode_t mode) |
8215534c MS |
192 | { |
193 | inode->i_mode = mode; | |
8215534c MS |
194 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
195 | } | |
196 | ||
197 | static inline void set_inode_attr(struct inode * inode, struct iattr * iattr) | |
198 | { | |
8215534c MS |
199 | inode->i_uid = iattr->ia_uid; |
200 | inode->i_gid = iattr->ia_gid; | |
201 | inode->i_atime = iattr->ia_atime; | |
202 | inode->i_mtime = iattr->ia_mtime; | |
203 | inode->i_ctime = iattr->ia_ctime; | |
204 | } | |
205 | ||
e61ab4ae EB |
206 | static void sysfs_refresh_inode(struct sysfs_dirent *sd, struct inode *inode) |
207 | { | |
208 | struct sysfs_inode_attrs *iattrs = sd->s_iattr; | |
209 | ||
210 | inode->i_mode = sd->s_mode; | |
211 | if (iattrs) { | |
212 | /* sysfs_dirent has non-default attributes | |
213 | * get them from persistent copy in sysfs_dirent | |
214 | */ | |
215 | set_inode_attr(inode, &iattrs->ia_iattr); | |
216 | security_inode_notifysecctx(inode, | |
217 | iattrs->ia_secdata, | |
218 | iattrs->ia_secdata_len); | |
219 | } | |
54d20f00 GKH |
220 | |
221 | if (sysfs_type(sd) == SYSFS_DIR) | |
222 | set_nlink(inode, sd->s_dir.subdirs + 2); | |
e61ab4ae EB |
223 | } |
224 | ||
225 | int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) | |
226 | { | |
227 | struct sysfs_dirent *sd = dentry->d_fsdata; | |
228 | struct inode *inode = dentry->d_inode; | |
229 | ||
230 | mutex_lock(&sysfs_mutex); | |
231 | sysfs_refresh_inode(sd, inode); | |
232 | mutex_unlock(&sysfs_mutex); | |
233 | ||
234 | generic_fillattr(inode, stat); | |
235 | return 0; | |
236 | } | |
237 | ||
bc37e283 | 238 | static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode) |
1da177e4 | 239 | { |
372e88bd EB |
240 | struct bin_attribute *bin_attr; |
241 | ||
04256b4a | 242 | inode->i_private = sysfs_get(sd); |
fc9f54b9 TH |
243 | inode->i_mapping->a_ops = &sysfs_aops; |
244 | inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; | |
245 | inode->i_op = &sysfs_inode_operations; | |
fc9f54b9 | 246 | |
e61ab4ae EB |
247 | set_default_inode_attr(inode, sd->s_mode); |
248 | sysfs_refresh_inode(sd, inode); | |
372e88bd | 249 | |
372e88bd EB |
250 | /* initialize inode according to type */ |
251 | switch (sysfs_type(sd)) { | |
372e88bd EB |
252 | case SYSFS_DIR: |
253 | inode->i_op = &sysfs_dir_inode_operations; | |
254 | inode->i_fop = &sysfs_dir_operations; | |
372e88bd EB |
255 | break; |
256 | case SYSFS_KOBJ_ATTR: | |
257 | inode->i_size = PAGE_SIZE; | |
258 | inode->i_fop = &sysfs_file_operations; | |
259 | break; | |
260 | case SYSFS_KOBJ_BIN_ATTR: | |
b1fc3d61 | 261 | bin_attr = sd->s_bin_attr.bin_attr; |
372e88bd EB |
262 | inode->i_size = bin_attr->size; |
263 | inode->i_fop = &bin_fops; | |
264 | break; | |
265 | case SYSFS_KOBJ_LINK: | |
266 | inode->i_op = &sysfs_symlink_inode_operations; | |
267 | break; | |
268 | default: | |
269 | BUG(); | |
270 | } | |
271 | ||
272 | unlock_new_inode(inode); | |
fc9f54b9 TH |
273 | } |
274 | ||
275 | /** | |
8312a8d7 | 276 | * sysfs_get_inode - get inode for sysfs_dirent |
fac2622b | 277 | * @sb: super block |
fc9f54b9 TH |
278 | * @sd: sysfs_dirent to allocate inode for |
279 | * | |
8312a8d7 TH |
280 | * Get inode for @sd. If such inode doesn't exist, a new inode |
281 | * is allocated and basics are initialized. New inode is | |
282 | * returned locked. | |
fc9f54b9 TH |
283 | * |
284 | * LOCKING: | |
285 | * Kernel thread context (may sleep). | |
286 | * | |
287 | * RETURNS: | |
288 | * Pointer to allocated inode on success, NULL on failure. | |
289 | */ | |
fac2622b | 290 | struct inode * sysfs_get_inode(struct super_block *sb, struct sysfs_dirent *sd) |
fc9f54b9 TH |
291 | { |
292 | struct inode *inode; | |
293 | ||
fac2622b | 294 | inode = iget_locked(sb, sd->s_ino); |
8312a8d7 | 295 | if (inode && (inode->i_state & I_NEW)) |
fc9f54b9 TH |
296 | sysfs_init_inode(sd, inode); |
297 | ||
1da177e4 LT |
298 | return inode; |
299 | } | |
300 | ||
04256b4a EB |
301 | /* |
302 | * The sysfs_dirent serves as both an inode and a directory entry for sysfs. | |
303 | * To prevent the sysfs inode numbers from being freed prematurely we take a | |
304 | * reference to sysfs_dirent from the sysfs inode. A | |
01cd9fef | 305 | * super_operations.evict_inode() implementation is needed to drop that |
04256b4a EB |
306 | * reference upon inode destruction. |
307 | */ | |
01cd9fef | 308 | void sysfs_evict_inode(struct inode *inode) |
04256b4a EB |
309 | { |
310 | struct sysfs_dirent *sd = inode->i_private; | |
311 | ||
312 | truncate_inode_pages(&inode->i_data, 0); | |
dbd5768f | 313 | clear_inode(inode); |
04256b4a EB |
314 | sysfs_put(sd); |
315 | } | |
316 | ||
3ff195b0 | 317 | int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const void *ns, const char *name) |
1da177e4 | 318 | { |
fb6896da | 319 | struct sysfs_addrm_cxt acxt; |
41fc1c27 | 320 | struct sysfs_dirent *sd; |
641e6f30 | 321 | |
ce597919 EB |
322 | if (!dir_sd) { |
323 | WARN(1, KERN_WARNING "sysfs: can not remove '%s', no directory\n", | |
324 | name); | |
995982ca | 325 | return -ENOENT; |
ce597919 | 326 | } |
1da177e4 | 327 | |
fb6896da | 328 | sysfs_addrm_start(&acxt, dir_sd); |
608e266a | 329 | |
3ff195b0 | 330 | sd = sysfs_find_dirent(dir_sd, ns, name); |
41fc1c27 TH |
331 | if (sd) |
332 | sysfs_remove_one(&acxt, sd); | |
3007e997 | 333 | |
990e53f8 TH |
334 | sysfs_addrm_finish(&acxt); |
335 | ||
336 | if (sd) | |
fb6896da | 337 | return 0; |
990e53f8 TH |
338 | else |
339 | return -ENOENT; | |
1da177e4 | 340 | } |
e61ab4ae | 341 | |
10556cb2 | 342 | int sysfs_permission(struct inode *inode, int mask) |
e61ab4ae | 343 | { |
b74c79e9 NP |
344 | struct sysfs_dirent *sd; |
345 | ||
10556cb2 | 346 | if (mask & MAY_NOT_BLOCK) |
b74c79e9 NP |
347 | return -ECHILD; |
348 | ||
349 | sd = inode->i_private; | |
e61ab4ae EB |
350 | |
351 | mutex_lock(&sysfs_mutex); | |
352 | sysfs_refresh_inode(sd, inode); | |
353 | mutex_unlock(&sysfs_mutex); | |
354 | ||
2830ba7f | 355 | return generic_permission(inode, mask); |
e61ab4ae | 356 | } |