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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * file.c - operations for regular (text) files. | |
3 | */ | |
4 | ||
5 | #include <linux/module.h> | |
0eeca283 | 6 | #include <linux/fsnotify.h> |
1da177e4 | 7 | #include <linux/kobject.h> |
5f45f1a7 | 8 | #include <linux/namei.h> |
4508a7a7 | 9 | #include <linux/poll.h> |
94bebf4d | 10 | #include <linux/list.h> |
1da177e4 LT |
11 | #include <asm/uaccess.h> |
12 | #include <asm/semaphore.h> | |
13 | ||
14 | #include "sysfs.h" | |
15 | ||
823bccfc | 16 | #define to_sattr(a) container_of(a,struct subsys_attribute, attr) |
1da177e4 | 17 | |
3d41088f | 18 | /* |
1da177e4 LT |
19 | * Subsystem file operations. |
20 | * These operations allow subsystems to have files that can be | |
21 | * read/written. | |
22 | */ | |
23 | static ssize_t | |
24 | subsys_attr_show(struct kobject * kobj, struct attribute * attr, char * page) | |
25 | { | |
823bccfc | 26 | struct kset *kset = to_kset(kobj); |
1da177e4 | 27 | struct subsys_attribute * sattr = to_sattr(attr); |
c76d0abd | 28 | ssize_t ret = -EIO; |
1da177e4 LT |
29 | |
30 | if (sattr->show) | |
823bccfc | 31 | ret = sattr->show(kset, page); |
1da177e4 LT |
32 | return ret; |
33 | } | |
34 | ||
35 | static ssize_t | |
36 | subsys_attr_store(struct kobject * kobj, struct attribute * attr, | |
37 | const char * page, size_t count) | |
38 | { | |
823bccfc | 39 | struct kset *kset = to_kset(kobj); |
1da177e4 | 40 | struct subsys_attribute * sattr = to_sattr(attr); |
c76d0abd | 41 | ssize_t ret = -EIO; |
1da177e4 LT |
42 | |
43 | if (sattr->store) | |
823bccfc | 44 | ret = sattr->store(kset, page, count); |
1da177e4 LT |
45 | return ret; |
46 | } | |
47 | ||
48 | static struct sysfs_ops subsys_sysfs_ops = { | |
49 | .show = subsys_attr_show, | |
50 | .store = subsys_attr_store, | |
51 | }; | |
52 | ||
94bebf4d ON |
53 | /** |
54 | * add_to_collection - add buffer to a collection | |
55 | * @buffer: buffer to be added | |
f95d882d | 56 | * @node: inode of set to add to |
94bebf4d | 57 | */ |
1da177e4 | 58 | |
94bebf4d ON |
59 | static inline void |
60 | add_to_collection(struct sysfs_buffer *buffer, struct inode *node) | |
61 | { | |
62 | struct sysfs_buffer_collection *set = node->i_private; | |
1da177e4 | 63 | |
94bebf4d ON |
64 | mutex_lock(&node->i_mutex); |
65 | list_add(&buffer->associates, &set->associates); | |
66 | mutex_unlock(&node->i_mutex); | |
67 | } | |
68 | ||
69 | static inline void | |
70 | remove_from_collection(struct sysfs_buffer *buffer, struct inode *node) | |
71 | { | |
72 | mutex_lock(&node->i_mutex); | |
73 | list_del(&buffer->associates); | |
74 | mutex_unlock(&node->i_mutex); | |
75 | } | |
1da177e4 LT |
76 | |
77 | /** | |
78 | * fill_read_buffer - allocate and fill buffer from object. | |
79 | * @dentry: dentry pointer. | |
80 | * @buffer: data buffer for file. | |
81 | * | |
82 | * Allocate @buffer->page, if it hasn't been already, then call the | |
83 | * kobject's show() method to fill the buffer with this attribute's | |
84 | * data. | |
82244b16 ON |
85 | * This is called only once, on the file's first read unless an error |
86 | * is returned. | |
1da177e4 LT |
87 | */ |
88 | static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer) | |
89 | { | |
4508a7a7 | 90 | struct sysfs_dirent * sd = dentry->d_fsdata; |
1da177e4 LT |
91 | struct attribute * attr = to_attr(dentry); |
92 | struct kobject * kobj = to_kobj(dentry->d_parent); | |
93 | struct sysfs_ops * ops = buffer->ops; | |
94 | int ret = 0; | |
95 | ssize_t count; | |
96 | ||
97 | if (!buffer->page) | |
98 | buffer->page = (char *) get_zeroed_page(GFP_KERNEL); | |
99 | if (!buffer->page) | |
100 | return -ENOMEM; | |
101 | ||
4508a7a7 | 102 | buffer->event = atomic_read(&sd->s_event); |
1da177e4 | 103 | count = ops->show(kobj,attr,buffer->page); |
1da177e4 | 104 | BUG_ON(count > (ssize_t)PAGE_SIZE); |
82244b16 ON |
105 | if (count >= 0) { |
106 | buffer->needs_read_fill = 0; | |
1da177e4 | 107 | buffer->count = count; |
82244b16 | 108 | } else { |
1da177e4 | 109 | ret = count; |
82244b16 | 110 | } |
1da177e4 LT |
111 | return ret; |
112 | } | |
113 | ||
1da177e4 LT |
114 | /** |
115 | * sysfs_read_file - read an attribute. | |
116 | * @file: file pointer. | |
117 | * @buf: buffer to fill. | |
118 | * @count: number of bytes to read. | |
119 | * @ppos: starting offset in file. | |
120 | * | |
121 | * Userspace wants to read an attribute file. The attribute descriptor | |
122 | * is in the file's ->d_fsdata. The target object is in the directory's | |
123 | * ->d_fsdata. | |
124 | * | |
125 | * We call fill_read_buffer() to allocate and fill the buffer from the | |
126 | * object's show() method exactly once (if the read is happening from | |
127 | * the beginning of the file). That should fill the entire buffer with | |
128 | * all the data the object has to offer for that attribute. | |
129 | * We then call flush_read_buffer() to copy the buffer to userspace | |
130 | * in the increments specified. | |
131 | */ | |
132 | ||
133 | static ssize_t | |
134 | sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
135 | { | |
136 | struct sysfs_buffer * buffer = file->private_data; | |
137 | ssize_t retval = 0; | |
138 | ||
139 | down(&buffer->sem); | |
140 | if (buffer->needs_read_fill) { | |
e7b0d26a AS |
141 | if (buffer->orphaned) |
142 | retval = -ENODEV; | |
143 | else | |
144 | retval = fill_read_buffer(file->f_path.dentry,buffer); | |
145 | if (retval) | |
1da177e4 LT |
146 | goto out; |
147 | } | |
5c1fdf41 ZB |
148 | pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n", |
149 | __FUNCTION__, count, *ppos, buffer->page); | |
92f4c701 AM |
150 | retval = simple_read_from_buffer(buf, count, ppos, buffer->page, |
151 | buffer->count); | |
1da177e4 LT |
152 | out: |
153 | up(&buffer->sem); | |
154 | return retval; | |
155 | } | |
156 | ||
1da177e4 LT |
157 | /** |
158 | * fill_write_buffer - copy buffer from userspace. | |
159 | * @buffer: data buffer for file. | |
67be2dd1 | 160 | * @buf: data from user. |
1da177e4 LT |
161 | * @count: number of bytes in @userbuf. |
162 | * | |
163 | * Allocate @buffer->page if it hasn't been already, then | |
164 | * copy the user-supplied buffer into it. | |
165 | */ | |
166 | ||
167 | static int | |
168 | fill_write_buffer(struct sysfs_buffer * buffer, const char __user * buf, size_t count) | |
169 | { | |
170 | int error; | |
171 | ||
172 | if (!buffer->page) | |
173 | buffer->page = (char *)get_zeroed_page(GFP_KERNEL); | |
174 | if (!buffer->page) | |
175 | return -ENOMEM; | |
176 | ||
177 | if (count >= PAGE_SIZE) | |
6e0dd741 | 178 | count = PAGE_SIZE - 1; |
1da177e4 LT |
179 | error = copy_from_user(buffer->page,buf,count); |
180 | buffer->needs_read_fill = 1; | |
035ed7a4 TM |
181 | /* if buf is assumed to contain a string, terminate it by \0, |
182 | so e.g. sscanf() can scan the string easily */ | |
183 | buffer->page[count] = 0; | |
1da177e4 LT |
184 | return error ? -EFAULT : count; |
185 | } | |
186 | ||
187 | ||
188 | /** | |
189 | * flush_write_buffer - push buffer to kobject. | |
3d41088f | 190 | * @dentry: dentry to the attribute |
1da177e4 | 191 | * @buffer: data buffer for file. |
3d41088f | 192 | * @count: number of bytes |
1da177e4 LT |
193 | * |
194 | * Get the correct pointers for the kobject and the attribute we're | |
195 | * dealing with, then call the store() method for the attribute, | |
196 | * passing the buffer that we acquired in fill_write_buffer(). | |
197 | */ | |
198 | ||
199 | static int | |
200 | flush_write_buffer(struct dentry * dentry, struct sysfs_buffer * buffer, size_t count) | |
201 | { | |
202 | struct attribute * attr = to_attr(dentry); | |
203 | struct kobject * kobj = to_kobj(dentry->d_parent); | |
204 | struct sysfs_ops * ops = buffer->ops; | |
205 | ||
206 | return ops->store(kobj,attr,buffer->page,count); | |
207 | } | |
208 | ||
209 | ||
210 | /** | |
211 | * sysfs_write_file - write an attribute. | |
212 | * @file: file pointer | |
213 | * @buf: data to write | |
214 | * @count: number of bytes | |
215 | * @ppos: starting offset | |
216 | * | |
217 | * Similar to sysfs_read_file(), though working in the opposite direction. | |
218 | * We allocate and fill the data from the user in fill_write_buffer(), | |
219 | * then push it to the kobject in flush_write_buffer(). | |
220 | * There is no easy way for us to know if userspace is only doing a partial | |
221 | * write, so we don't support them. We expect the entire buffer to come | |
222 | * on the first write. | |
223 | * Hint: if you're writing a value, first read the file, modify only the | |
224 | * the value you're changing, then write entire buffer back. | |
225 | */ | |
226 | ||
227 | static ssize_t | |
228 | sysfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
229 | { | |
230 | struct sysfs_buffer * buffer = file->private_data; | |
231 | ssize_t len; | |
232 | ||
233 | down(&buffer->sem); | |
94bebf4d ON |
234 | if (buffer->orphaned) { |
235 | len = -ENODEV; | |
236 | goto out; | |
237 | } | |
1da177e4 LT |
238 | len = fill_write_buffer(buffer, buf, count); |
239 | if (len > 0) | |
f427f5d5 | 240 | len = flush_write_buffer(file->f_path.dentry, buffer, len); |
1da177e4 LT |
241 | if (len > 0) |
242 | *ppos += len; | |
94bebf4d | 243 | out: |
1da177e4 LT |
244 | up(&buffer->sem); |
245 | return len; | |
246 | } | |
247 | ||
94bebf4d | 248 | static int sysfs_open_file(struct inode *inode, struct file *file) |
1da177e4 | 249 | { |
f427f5d5 JJS |
250 | struct kobject *kobj = sysfs_get_kobject(file->f_path.dentry->d_parent); |
251 | struct attribute * attr = to_attr(file->f_path.dentry); | |
94bebf4d | 252 | struct sysfs_buffer_collection *set; |
1da177e4 LT |
253 | struct sysfs_buffer * buffer; |
254 | struct sysfs_ops * ops = NULL; | |
255 | int error = 0; | |
256 | ||
257 | if (!kobj || !attr) | |
258 | goto Einval; | |
259 | ||
260 | /* Grab the module reference for this attribute if we have one */ | |
261 | if (!try_module_get(attr->owner)) { | |
262 | error = -ENODEV; | |
263 | goto Done; | |
264 | } | |
265 | ||
266 | /* if the kobject has no ktype, then we assume that it is a subsystem | |
267 | * itself, and use ops for it. | |
268 | */ | |
269 | if (kobj->kset && kobj->kset->ktype) | |
270 | ops = kobj->kset->ktype->sysfs_ops; | |
271 | else if (kobj->ktype) | |
272 | ops = kobj->ktype->sysfs_ops; | |
273 | else | |
274 | ops = &subsys_sysfs_ops; | |
275 | ||
276 | /* No sysfs operations, either from having no subsystem, | |
277 | * or the subsystem have no operations. | |
278 | */ | |
279 | if (!ops) | |
280 | goto Eaccess; | |
281 | ||
94bebf4d ON |
282 | /* make sure we have a collection to add our buffers to */ |
283 | mutex_lock(&inode->i_mutex); | |
284 | if (!(set = inode->i_private)) { | |
285 | if (!(set = inode->i_private = kmalloc(sizeof(struct sysfs_buffer_collection), GFP_KERNEL))) { | |
286 | error = -ENOMEM; | |
287 | goto Done; | |
288 | } else { | |
289 | INIT_LIST_HEAD(&set->associates); | |
290 | } | |
291 | } | |
292 | mutex_unlock(&inode->i_mutex); | |
293 | ||
1da177e4 LT |
294 | /* File needs write support. |
295 | * The inode's perms must say it's ok, | |
296 | * and we must have a store method. | |
297 | */ | |
298 | if (file->f_mode & FMODE_WRITE) { | |
299 | ||
300 | if (!(inode->i_mode & S_IWUGO) || !ops->store) | |
301 | goto Eaccess; | |
302 | ||
303 | } | |
304 | ||
305 | /* File needs read support. | |
306 | * The inode's perms must say it's ok, and we there | |
307 | * must be a show method for it. | |
308 | */ | |
309 | if (file->f_mode & FMODE_READ) { | |
310 | if (!(inode->i_mode & S_IRUGO) || !ops->show) | |
311 | goto Eaccess; | |
312 | } | |
313 | ||
314 | /* No error? Great, allocate a buffer for the file, and store it | |
315 | * it in file->private_data for easy access. | |
316 | */ | |
58d49283 | 317 | buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL); |
1da177e4 | 318 | if (buffer) { |
94bebf4d | 319 | INIT_LIST_HEAD(&buffer->associates); |
1da177e4 LT |
320 | init_MUTEX(&buffer->sem); |
321 | buffer->needs_read_fill = 1; | |
322 | buffer->ops = ops; | |
94bebf4d | 323 | add_to_collection(buffer, inode); |
1da177e4 LT |
324 | file->private_data = buffer; |
325 | } else | |
326 | error = -ENOMEM; | |
327 | goto Done; | |
328 | ||
329 | Einval: | |
330 | error = -EINVAL; | |
331 | goto Done; | |
332 | Eaccess: | |
333 | error = -EACCES; | |
334 | module_put(attr->owner); | |
335 | Done: | |
f7506536 | 336 | if (error) |
1da177e4 LT |
337 | kobject_put(kobj); |
338 | return error; | |
339 | } | |
340 | ||
1da177e4 LT |
341 | static int sysfs_release(struct inode * inode, struct file * filp) |
342 | { | |
f427f5d5 JJS |
343 | struct kobject * kobj = to_kobj(filp->f_path.dentry->d_parent); |
344 | struct attribute * attr = to_attr(filp->f_path.dentry); | |
1da177e4 LT |
345 | struct module * owner = attr->owner; |
346 | struct sysfs_buffer * buffer = filp->private_data; | |
347 | ||
94bebf4d ON |
348 | if (buffer) |
349 | remove_from_collection(buffer, inode); | |
f7506536 | 350 | kobject_put(kobj); |
1da177e4 LT |
351 | /* After this point, attr should not be accessed. */ |
352 | module_put(owner); | |
353 | ||
354 | if (buffer) { | |
355 | if (buffer->page) | |
356 | free_page((unsigned long)buffer->page); | |
357 | kfree(buffer); | |
358 | } | |
359 | return 0; | |
360 | } | |
361 | ||
4508a7a7 N |
362 | /* Sysfs attribute files are pollable. The idea is that you read |
363 | * the content and then you use 'poll' or 'select' to wait for | |
364 | * the content to change. When the content changes (assuming the | |
365 | * manager for the kobject supports notification), poll will | |
366 | * return POLLERR|POLLPRI, and select will return the fd whether | |
367 | * it is waiting for read, write, or exceptions. | |
368 | * Once poll/select indicates that the value has changed, you | |
369 | * need to close and re-open the file, as simply seeking and reading | |
370 | * again will not get new data, or reset the state of 'poll'. | |
371 | * Reminder: this only works for attributes which actively support | |
372 | * it, and it is not possible to test an attribute from userspace | |
373 | * to see if it supports poll (Nether 'poll' or 'select' return | |
374 | * an appropriate error code). When in doubt, set a suitable timeout value. | |
375 | */ | |
376 | static unsigned int sysfs_poll(struct file *filp, poll_table *wait) | |
377 | { | |
378 | struct sysfs_buffer * buffer = filp->private_data; | |
f427f5d5 JJS |
379 | struct kobject * kobj = to_kobj(filp->f_path.dentry->d_parent); |
380 | struct sysfs_dirent * sd = filp->f_path.dentry->d_fsdata; | |
4508a7a7 N |
381 | int res = 0; |
382 | ||
383 | poll_wait(filp, &kobj->poll, wait); | |
384 | ||
385 | if (buffer->event != atomic_read(&sd->s_event)) { | |
386 | res = POLLERR|POLLPRI; | |
387 | buffer->needs_read_fill = 1; | |
388 | } | |
389 | ||
390 | return res; | |
391 | } | |
392 | ||
393 | ||
394 | static struct dentry *step_down(struct dentry *dir, const char * name) | |
395 | { | |
396 | struct dentry * de; | |
397 | ||
398 | if (dir == NULL || dir->d_inode == NULL) | |
399 | return NULL; | |
400 | ||
401 | mutex_lock(&dir->d_inode->i_mutex); | |
402 | de = lookup_one_len(name, dir, strlen(name)); | |
403 | mutex_unlock(&dir->d_inode->i_mutex); | |
404 | dput(dir); | |
405 | if (IS_ERR(de)) | |
406 | return NULL; | |
407 | if (de->d_inode == NULL) { | |
408 | dput(de); | |
409 | return NULL; | |
410 | } | |
411 | return de; | |
412 | } | |
413 | ||
414 | void sysfs_notify(struct kobject * k, char *dir, char *attr) | |
415 | { | |
416 | struct dentry *de = k->dentry; | |
417 | if (de) | |
418 | dget(de); | |
419 | if (de && dir) | |
420 | de = step_down(de, dir); | |
421 | if (de && attr) | |
422 | de = step_down(de, attr); | |
423 | if (de) { | |
424 | struct sysfs_dirent * sd = de->d_fsdata; | |
425 | if (sd) | |
426 | atomic_inc(&sd->s_event); | |
427 | wake_up_interruptible(&k->poll); | |
428 | dput(de); | |
429 | } | |
430 | } | |
431 | EXPORT_SYMBOL_GPL(sysfs_notify); | |
432 | ||
4b6f5d20 | 433 | const struct file_operations sysfs_file_operations = { |
1da177e4 LT |
434 | .read = sysfs_read_file, |
435 | .write = sysfs_write_file, | |
436 | .llseek = generic_file_llseek, | |
437 | .open = sysfs_open_file, | |
438 | .release = sysfs_release, | |
4508a7a7 | 439 | .poll = sysfs_poll, |
1da177e4 LT |
440 | }; |
441 | ||
442 | ||
443 | int sysfs_add_file(struct dentry * dir, const struct attribute * attr, int type) | |
444 | { | |
445 | struct sysfs_dirent * parent_sd = dir->d_fsdata; | |
446 | umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG; | |
c516865c | 447 | int error = -EEXIST; |
1da177e4 | 448 | |
1b1dcc1b | 449 | mutex_lock(&dir->d_inode->i_mutex); |
c516865c MS |
450 | if (!sysfs_dirent_exist(parent_sd, attr->name)) |
451 | error = sysfs_make_dirent(parent_sd, NULL, (void *)attr, | |
452 | mode, type); | |
1b1dcc1b | 453 | mutex_unlock(&dir->d_inode->i_mutex); |
1da177e4 LT |
454 | |
455 | return error; | |
456 | } | |
457 | ||
458 | ||
459 | /** | |
460 | * sysfs_create_file - create an attribute file for an object. | |
461 | * @kobj: object we're creating for. | |
462 | * @attr: atrribute descriptor. | |
463 | */ | |
464 | ||
465 | int sysfs_create_file(struct kobject * kobj, const struct attribute * attr) | |
466 | { | |
467 | BUG_ON(!kobj || !kobj->dentry || !attr); | |
468 | ||
469 | return sysfs_add_file(kobj->dentry, attr, SYSFS_KOBJ_ATTR); | |
470 | ||
471 | } | |
472 | ||
473 | ||
dfa87c82 AS |
474 | /** |
475 | * sysfs_add_file_to_group - add an attribute file to a pre-existing group. | |
476 | * @kobj: object we're acting for. | |
477 | * @attr: attribute descriptor. | |
478 | * @group: group name. | |
479 | */ | |
480 | int sysfs_add_file_to_group(struct kobject *kobj, | |
481 | const struct attribute *attr, const char *group) | |
482 | { | |
483 | struct dentry *dir; | |
484 | int error; | |
485 | ||
486 | dir = lookup_one_len(group, kobj->dentry, strlen(group)); | |
487 | if (IS_ERR(dir)) | |
488 | error = PTR_ERR(dir); | |
489 | else { | |
490 | error = sysfs_add_file(dir, attr, SYSFS_KOBJ_ATTR); | |
491 | dput(dir); | |
492 | } | |
493 | return error; | |
494 | } | |
495 | EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); | |
496 | ||
497 | ||
1da177e4 LT |
498 | /** |
499 | * sysfs_update_file - update the modified timestamp on an object attribute. | |
500 | * @kobj: object we're acting for. | |
501 | * @attr: attribute descriptor. | |
1da177e4 LT |
502 | */ |
503 | int sysfs_update_file(struct kobject * kobj, const struct attribute * attr) | |
504 | { | |
505 | struct dentry * dir = kobj->dentry; | |
506 | struct dentry * victim; | |
507 | int res = -ENOENT; | |
508 | ||
1b1dcc1b | 509 | mutex_lock(&dir->d_inode->i_mutex); |
5f45f1a7 | 510 | victim = lookup_one_len(attr->name, dir, strlen(attr->name)); |
1da177e4 LT |
511 | if (!IS_ERR(victim)) { |
512 | /* make sure dentry is really there */ | |
513 | if (victim->d_inode && | |
514 | (victim->d_parent->d_inode == dir->d_inode)) { | |
515 | victim->d_inode->i_mtime = CURRENT_TIME; | |
0eeca283 | 516 | fsnotify_modify(victim); |
1da177e4 LT |
517 | res = 0; |
518 | } else | |
519 | d_drop(victim); | |
520 | ||
521 | /** | |
97a50184 | 522 | * Drop the reference acquired from lookup_one_len() above. |
1da177e4 LT |
523 | */ |
524 | dput(victim); | |
525 | } | |
1b1dcc1b | 526 | mutex_unlock(&dir->d_inode->i_mutex); |
1da177e4 LT |
527 | |
528 | return res; | |
529 | } | |
530 | ||
531 | ||
31e5abe9 KS |
532 | /** |
533 | * sysfs_chmod_file - update the modified mode value on an object attribute. | |
534 | * @kobj: object we're acting for. | |
535 | * @attr: attribute descriptor. | |
536 | * @mode: file permissions. | |
537 | * | |
538 | */ | |
539 | int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode) | |
540 | { | |
541 | struct dentry *dir = kobj->dentry; | |
542 | struct dentry *victim; | |
bc062b1b MS |
543 | struct inode * inode; |
544 | struct iattr newattrs; | |
31e5abe9 KS |
545 | int res = -ENOENT; |
546 | ||
1b1dcc1b | 547 | mutex_lock(&dir->d_inode->i_mutex); |
5f45f1a7 | 548 | victim = lookup_one_len(attr->name, dir, strlen(attr->name)); |
31e5abe9 KS |
549 | if (!IS_ERR(victim)) { |
550 | if (victim->d_inode && | |
551 | (victim->d_parent->d_inode == dir->d_inode)) { | |
bc062b1b | 552 | inode = victim->d_inode; |
1b1dcc1b | 553 | mutex_lock(&inode->i_mutex); |
bc062b1b MS |
554 | newattrs.ia_mode = (mode & S_IALLUGO) | |
555 | (inode->i_mode & ~S_IALLUGO); | |
556 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; | |
557 | res = notify_change(victim, &newattrs); | |
1b1dcc1b | 558 | mutex_unlock(&inode->i_mutex); |
31e5abe9 | 559 | } |
bc062b1b | 560 | dput(victim); |
31e5abe9 | 561 | } |
1b1dcc1b | 562 | mutex_unlock(&dir->d_inode->i_mutex); |
31e5abe9 KS |
563 | |
564 | return res; | |
565 | } | |
566 | EXPORT_SYMBOL_GPL(sysfs_chmod_file); | |
567 | ||
568 | ||
1da177e4 LT |
569 | /** |
570 | * sysfs_remove_file - remove an object attribute. | |
571 | * @kobj: object we're acting for. | |
572 | * @attr: attribute descriptor. | |
573 | * | |
574 | * Hash the attribute name and kill the victim. | |
575 | */ | |
576 | ||
577 | void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr) | |
578 | { | |
94bebf4d | 579 | sysfs_hash_and_remove(kobj->dentry, attr->name); |
1da177e4 LT |
580 | } |
581 | ||
582 | ||
dfa87c82 AS |
583 | /** |
584 | * sysfs_remove_file_from_group - remove an attribute file from a group. | |
585 | * @kobj: object we're acting for. | |
586 | * @attr: attribute descriptor. | |
587 | * @group: group name. | |
588 | */ | |
589 | void sysfs_remove_file_from_group(struct kobject *kobj, | |
590 | const struct attribute *attr, const char *group) | |
591 | { | |
592 | struct dentry *dir; | |
593 | ||
594 | dir = lookup_one_len(group, kobj->dentry, strlen(group)); | |
595 | if (!IS_ERR(dir)) { | |
596 | sysfs_hash_and_remove(dir, attr->name); | |
597 | dput(dir); | |
598 | } | |
599 | } | |
600 | EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); | |
601 | ||
d9a9cdfb AS |
602 | struct sysfs_schedule_callback_struct { |
603 | struct kobject *kobj; | |
604 | void (*func)(void *); | |
605 | void *data; | |
523ded71 | 606 | struct module *owner; |
d9a9cdfb AS |
607 | struct work_struct work; |
608 | }; | |
609 | ||
610 | static void sysfs_schedule_callback_work(struct work_struct *work) | |
611 | { | |
612 | struct sysfs_schedule_callback_struct *ss = container_of(work, | |
613 | struct sysfs_schedule_callback_struct, work); | |
614 | ||
615 | (ss->func)(ss->data); | |
616 | kobject_put(ss->kobj); | |
523ded71 | 617 | module_put(ss->owner); |
d9a9cdfb AS |
618 | kfree(ss); |
619 | } | |
620 | ||
621 | /** | |
622 | * sysfs_schedule_callback - helper to schedule a callback for a kobject | |
623 | * @kobj: object we're acting for. | |
624 | * @func: callback function to invoke later. | |
625 | * @data: argument to pass to @func. | |
523ded71 | 626 | * @owner: module owning the callback code |
d9a9cdfb AS |
627 | * |
628 | * sysfs attribute methods must not unregister themselves or their parent | |
629 | * kobject (which would amount to the same thing). Attempts to do so will | |
630 | * deadlock, since unregistration is mutually exclusive with driver | |
631 | * callbacks. | |
632 | * | |
633 | * Instead methods can call this routine, which will attempt to allocate | |
634 | * and schedule a workqueue request to call back @func with @data as its | |
635 | * argument in the workqueue's process context. @kobj will be pinned | |
636 | * until @func returns. | |
637 | * | |
638 | * Returns 0 if the request was submitted, -ENOMEM if storage could not | |
523ded71 | 639 | * be allocated, -ENODEV if a reference to @owner isn't available. |
d9a9cdfb AS |
640 | */ |
641 | int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), | |
523ded71 | 642 | void *data, struct module *owner) |
d9a9cdfb AS |
643 | { |
644 | struct sysfs_schedule_callback_struct *ss; | |
645 | ||
523ded71 AS |
646 | if (!try_module_get(owner)) |
647 | return -ENODEV; | |
d9a9cdfb | 648 | ss = kmalloc(sizeof(*ss), GFP_KERNEL); |
523ded71 AS |
649 | if (!ss) { |
650 | module_put(owner); | |
d9a9cdfb | 651 | return -ENOMEM; |
523ded71 | 652 | } |
d9a9cdfb AS |
653 | kobject_get(kobj); |
654 | ss->kobj = kobj; | |
655 | ss->func = func; | |
656 | ss->data = data; | |
523ded71 | 657 | ss->owner = owner; |
d9a9cdfb AS |
658 | INIT_WORK(&ss->work, sysfs_schedule_callback_work); |
659 | schedule_work(&ss->work); | |
660 | return 0; | |
661 | } | |
662 | EXPORT_SYMBOL_GPL(sysfs_schedule_callback); | |
663 | ||
dfa87c82 | 664 | |
1da177e4 LT |
665 | EXPORT_SYMBOL_GPL(sysfs_create_file); |
666 | EXPORT_SYMBOL_GPL(sysfs_remove_file); | |
667 | EXPORT_SYMBOL_GPL(sysfs_update_file); |