Commit | Line | Data |
---|---|---|
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 | ||
114 | ||
115 | /** | |
116 | * flush_read_buffer - push buffer to userspace. | |
117 | * @buffer: data buffer for file. | |
67be2dd1 | 118 | * @buf: user-passed buffer. |
1da177e4 LT |
119 | * @count: number of bytes requested. |
120 | * @ppos: file position. | |
121 | * | |
122 | * Copy the buffer we filled in fill_read_buffer() to userspace. | |
123 | * This is done at the reader's leisure, copying and advancing | |
124 | * the amount they specify each time. | |
125 | * This may be called continuously until the buffer is empty. | |
126 | */ | |
127 | static int flush_read_buffer(struct sysfs_buffer * buffer, char __user * buf, | |
128 | size_t count, loff_t * ppos) | |
129 | { | |
130 | int error; | |
131 | ||
132 | if (*ppos > buffer->count) | |
133 | return 0; | |
134 | ||
135 | if (count > (buffer->count - *ppos)) | |
136 | count = buffer->count - *ppos; | |
137 | ||
138 | error = copy_to_user(buf,buffer->page + *ppos,count); | |
139 | if (!error) | |
140 | *ppos += count; | |
141 | return error ? -EFAULT : count; | |
142 | } | |
143 | ||
144 | /** | |
145 | * sysfs_read_file - read an attribute. | |
146 | * @file: file pointer. | |
147 | * @buf: buffer to fill. | |
148 | * @count: number of bytes to read. | |
149 | * @ppos: starting offset in file. | |
150 | * | |
151 | * Userspace wants to read an attribute file. The attribute descriptor | |
152 | * is in the file's ->d_fsdata. The target object is in the directory's | |
153 | * ->d_fsdata. | |
154 | * | |
155 | * We call fill_read_buffer() to allocate and fill the buffer from the | |
156 | * object's show() method exactly once (if the read is happening from | |
157 | * the beginning of the file). That should fill the entire buffer with | |
158 | * all the data the object has to offer for that attribute. | |
159 | * We then call flush_read_buffer() to copy the buffer to userspace | |
160 | * in the increments specified. | |
161 | */ | |
162 | ||
163 | static ssize_t | |
164 | sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
165 | { | |
166 | struct sysfs_buffer * buffer = file->private_data; | |
167 | ssize_t retval = 0; | |
168 | ||
169 | down(&buffer->sem); | |
170 | if (buffer->needs_read_fill) { | |
e7b0d26a AS |
171 | if (buffer->orphaned) |
172 | retval = -ENODEV; | |
173 | else | |
174 | retval = fill_read_buffer(file->f_path.dentry,buffer); | |
175 | if (retval) | |
1da177e4 LT |
176 | goto out; |
177 | } | |
5c1fdf41 ZB |
178 | pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n", |
179 | __FUNCTION__, count, *ppos, buffer->page); | |
1da177e4 LT |
180 | retval = flush_read_buffer(buffer,buf,count,ppos); |
181 | out: | |
182 | up(&buffer->sem); | |
183 | return retval; | |
184 | } | |
185 | ||
1da177e4 LT |
186 | /** |
187 | * fill_write_buffer - copy buffer from userspace. | |
188 | * @buffer: data buffer for file. | |
67be2dd1 | 189 | * @buf: data from user. |
1da177e4 LT |
190 | * @count: number of bytes in @userbuf. |
191 | * | |
192 | * Allocate @buffer->page if it hasn't been already, then | |
193 | * copy the user-supplied buffer into it. | |
194 | */ | |
195 | ||
196 | static int | |
197 | fill_write_buffer(struct sysfs_buffer * buffer, const char __user * buf, size_t count) | |
198 | { | |
199 | int error; | |
200 | ||
201 | if (!buffer->page) | |
202 | buffer->page = (char *)get_zeroed_page(GFP_KERNEL); | |
203 | if (!buffer->page) | |
204 | return -ENOMEM; | |
205 | ||
206 | if (count >= PAGE_SIZE) | |
6e0dd741 | 207 | count = PAGE_SIZE - 1; |
1da177e4 LT |
208 | error = copy_from_user(buffer->page,buf,count); |
209 | buffer->needs_read_fill = 1; | |
035ed7a4 TM |
210 | /* if buf is assumed to contain a string, terminate it by \0, |
211 | so e.g. sscanf() can scan the string easily */ | |
212 | buffer->page[count] = 0; | |
1da177e4 LT |
213 | return error ? -EFAULT : count; |
214 | } | |
215 | ||
216 | ||
217 | /** | |
218 | * flush_write_buffer - push buffer to kobject. | |
3d41088f | 219 | * @dentry: dentry to the attribute |
1da177e4 | 220 | * @buffer: data buffer for file. |
3d41088f | 221 | * @count: number of bytes |
1da177e4 LT |
222 | * |
223 | * Get the correct pointers for the kobject and the attribute we're | |
224 | * dealing with, then call the store() method for the attribute, | |
225 | * passing the buffer that we acquired in fill_write_buffer(). | |
226 | */ | |
227 | ||
228 | static int | |
229 | flush_write_buffer(struct dentry * dentry, struct sysfs_buffer * buffer, size_t count) | |
230 | { | |
231 | struct attribute * attr = to_attr(dentry); | |
232 | struct kobject * kobj = to_kobj(dentry->d_parent); | |
233 | struct sysfs_ops * ops = buffer->ops; | |
234 | ||
235 | return ops->store(kobj,attr,buffer->page,count); | |
236 | } | |
237 | ||
238 | ||
239 | /** | |
240 | * sysfs_write_file - write an attribute. | |
241 | * @file: file pointer | |
242 | * @buf: data to write | |
243 | * @count: number of bytes | |
244 | * @ppos: starting offset | |
245 | * | |
246 | * Similar to sysfs_read_file(), though working in the opposite direction. | |
247 | * We allocate and fill the data from the user in fill_write_buffer(), | |
248 | * then push it to the kobject in flush_write_buffer(). | |
249 | * There is no easy way for us to know if userspace is only doing a partial | |
250 | * write, so we don't support them. We expect the entire buffer to come | |
251 | * on the first write. | |
252 | * Hint: if you're writing a value, first read the file, modify only the | |
253 | * the value you're changing, then write entire buffer back. | |
254 | */ | |
255 | ||
256 | static ssize_t | |
257 | sysfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
258 | { | |
259 | struct sysfs_buffer * buffer = file->private_data; | |
260 | ssize_t len; | |
261 | ||
262 | down(&buffer->sem); | |
94bebf4d ON |
263 | if (buffer->orphaned) { |
264 | len = -ENODEV; | |
265 | goto out; | |
266 | } | |
1da177e4 LT |
267 | len = fill_write_buffer(buffer, buf, count); |
268 | if (len > 0) | |
f427f5d5 | 269 | len = flush_write_buffer(file->f_path.dentry, buffer, len); |
1da177e4 LT |
270 | if (len > 0) |
271 | *ppos += len; | |
94bebf4d | 272 | out: |
1da177e4 LT |
273 | up(&buffer->sem); |
274 | return len; | |
275 | } | |
276 | ||
94bebf4d | 277 | static int sysfs_open_file(struct inode *inode, struct file *file) |
1da177e4 | 278 | { |
f427f5d5 JJS |
279 | struct kobject *kobj = sysfs_get_kobject(file->f_path.dentry->d_parent); |
280 | struct attribute * attr = to_attr(file->f_path.dentry); | |
94bebf4d | 281 | struct sysfs_buffer_collection *set; |
1da177e4 LT |
282 | struct sysfs_buffer * buffer; |
283 | struct sysfs_ops * ops = NULL; | |
284 | int error = 0; | |
285 | ||
286 | if (!kobj || !attr) | |
287 | goto Einval; | |
288 | ||
289 | /* Grab the module reference for this attribute if we have one */ | |
290 | if (!try_module_get(attr->owner)) { | |
291 | error = -ENODEV; | |
292 | goto Done; | |
293 | } | |
294 | ||
295 | /* if the kobject has no ktype, then we assume that it is a subsystem | |
296 | * itself, and use ops for it. | |
297 | */ | |
298 | if (kobj->kset && kobj->kset->ktype) | |
299 | ops = kobj->kset->ktype->sysfs_ops; | |
300 | else if (kobj->ktype) | |
301 | ops = kobj->ktype->sysfs_ops; | |
302 | else | |
303 | ops = &subsys_sysfs_ops; | |
304 | ||
305 | /* No sysfs operations, either from having no subsystem, | |
306 | * or the subsystem have no operations. | |
307 | */ | |
308 | if (!ops) | |
309 | goto Eaccess; | |
310 | ||
94bebf4d ON |
311 | /* make sure we have a collection to add our buffers to */ |
312 | mutex_lock(&inode->i_mutex); | |
313 | if (!(set = inode->i_private)) { | |
314 | if (!(set = inode->i_private = kmalloc(sizeof(struct sysfs_buffer_collection), GFP_KERNEL))) { | |
315 | error = -ENOMEM; | |
316 | goto Done; | |
317 | } else { | |
318 | INIT_LIST_HEAD(&set->associates); | |
319 | } | |
320 | } | |
321 | mutex_unlock(&inode->i_mutex); | |
322 | ||
1da177e4 LT |
323 | /* File needs write support. |
324 | * The inode's perms must say it's ok, | |
325 | * and we must have a store method. | |
326 | */ | |
327 | if (file->f_mode & FMODE_WRITE) { | |
328 | ||
329 | if (!(inode->i_mode & S_IWUGO) || !ops->store) | |
330 | goto Eaccess; | |
331 | ||
332 | } | |
333 | ||
334 | /* File needs read support. | |
335 | * The inode's perms must say it's ok, and we there | |
336 | * must be a show method for it. | |
337 | */ | |
338 | if (file->f_mode & FMODE_READ) { | |
339 | if (!(inode->i_mode & S_IRUGO) || !ops->show) | |
340 | goto Eaccess; | |
341 | } | |
342 | ||
343 | /* No error? Great, allocate a buffer for the file, and store it | |
344 | * it in file->private_data for easy access. | |
345 | */ | |
58d49283 | 346 | buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL); |
1da177e4 | 347 | if (buffer) { |
94bebf4d | 348 | INIT_LIST_HEAD(&buffer->associates); |
1da177e4 LT |
349 | init_MUTEX(&buffer->sem); |
350 | buffer->needs_read_fill = 1; | |
351 | buffer->ops = ops; | |
94bebf4d | 352 | add_to_collection(buffer, inode); |
1da177e4 LT |
353 | file->private_data = buffer; |
354 | } else | |
355 | error = -ENOMEM; | |
356 | goto Done; | |
357 | ||
358 | Einval: | |
359 | error = -EINVAL; | |
360 | goto Done; | |
361 | Eaccess: | |
362 | error = -EACCES; | |
363 | module_put(attr->owner); | |
364 | Done: | |
f7506536 | 365 | if (error) |
1da177e4 LT |
366 | kobject_put(kobj); |
367 | return error; | |
368 | } | |
369 | ||
1da177e4 LT |
370 | static int sysfs_release(struct inode * inode, struct file * filp) |
371 | { | |
f427f5d5 JJS |
372 | struct kobject * kobj = to_kobj(filp->f_path.dentry->d_parent); |
373 | struct attribute * attr = to_attr(filp->f_path.dentry); | |
1da177e4 LT |
374 | struct module * owner = attr->owner; |
375 | struct sysfs_buffer * buffer = filp->private_data; | |
376 | ||
94bebf4d ON |
377 | if (buffer) |
378 | remove_from_collection(buffer, inode); | |
f7506536 | 379 | kobject_put(kobj); |
1da177e4 LT |
380 | /* After this point, attr should not be accessed. */ |
381 | module_put(owner); | |
382 | ||
383 | if (buffer) { | |
384 | if (buffer->page) | |
385 | free_page((unsigned long)buffer->page); | |
386 | kfree(buffer); | |
387 | } | |
388 | return 0; | |
389 | } | |
390 | ||
4508a7a7 N |
391 | /* Sysfs attribute files are pollable. The idea is that you read |
392 | * the content and then you use 'poll' or 'select' to wait for | |
393 | * the content to change. When the content changes (assuming the | |
394 | * manager for the kobject supports notification), poll will | |
395 | * return POLLERR|POLLPRI, and select will return the fd whether | |
396 | * it is waiting for read, write, or exceptions. | |
397 | * Once poll/select indicates that the value has changed, you | |
398 | * need to close and re-open the file, as simply seeking and reading | |
399 | * again will not get new data, or reset the state of 'poll'. | |
400 | * Reminder: this only works for attributes which actively support | |
401 | * it, and it is not possible to test an attribute from userspace | |
402 | * to see if it supports poll (Nether 'poll' or 'select' return | |
403 | * an appropriate error code). When in doubt, set a suitable timeout value. | |
404 | */ | |
405 | static unsigned int sysfs_poll(struct file *filp, poll_table *wait) | |
406 | { | |
407 | struct sysfs_buffer * buffer = filp->private_data; | |
f427f5d5 JJS |
408 | struct kobject * kobj = to_kobj(filp->f_path.dentry->d_parent); |
409 | struct sysfs_dirent * sd = filp->f_path.dentry->d_fsdata; | |
4508a7a7 N |
410 | int res = 0; |
411 | ||
412 | poll_wait(filp, &kobj->poll, wait); | |
413 | ||
414 | if (buffer->event != atomic_read(&sd->s_event)) { | |
415 | res = POLLERR|POLLPRI; | |
416 | buffer->needs_read_fill = 1; | |
417 | } | |
418 | ||
419 | return res; | |
420 | } | |
421 | ||
422 | ||
423 | static struct dentry *step_down(struct dentry *dir, const char * name) | |
424 | { | |
425 | struct dentry * de; | |
426 | ||
427 | if (dir == NULL || dir->d_inode == NULL) | |
428 | return NULL; | |
429 | ||
430 | mutex_lock(&dir->d_inode->i_mutex); | |
431 | de = lookup_one_len(name, dir, strlen(name)); | |
432 | mutex_unlock(&dir->d_inode->i_mutex); | |
433 | dput(dir); | |
434 | if (IS_ERR(de)) | |
435 | return NULL; | |
436 | if (de->d_inode == NULL) { | |
437 | dput(de); | |
438 | return NULL; | |
439 | } | |
440 | return de; | |
441 | } | |
442 | ||
443 | void sysfs_notify(struct kobject * k, char *dir, char *attr) | |
444 | { | |
445 | struct dentry *de = k->dentry; | |
446 | if (de) | |
447 | dget(de); | |
448 | if (de && dir) | |
449 | de = step_down(de, dir); | |
450 | if (de && attr) | |
451 | de = step_down(de, attr); | |
452 | if (de) { | |
453 | struct sysfs_dirent * sd = de->d_fsdata; | |
454 | if (sd) | |
455 | atomic_inc(&sd->s_event); | |
456 | wake_up_interruptible(&k->poll); | |
457 | dput(de); | |
458 | } | |
459 | } | |
460 | EXPORT_SYMBOL_GPL(sysfs_notify); | |
461 | ||
4b6f5d20 | 462 | const struct file_operations sysfs_file_operations = { |
1da177e4 LT |
463 | .read = sysfs_read_file, |
464 | .write = sysfs_write_file, | |
465 | .llseek = generic_file_llseek, | |
466 | .open = sysfs_open_file, | |
467 | .release = sysfs_release, | |
4508a7a7 | 468 | .poll = sysfs_poll, |
1da177e4 LT |
469 | }; |
470 | ||
471 | ||
472 | int sysfs_add_file(struct dentry * dir, const struct attribute * attr, int type) | |
473 | { | |
474 | struct sysfs_dirent * parent_sd = dir->d_fsdata; | |
475 | umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG; | |
c516865c | 476 | int error = -EEXIST; |
1da177e4 | 477 | |
1b1dcc1b | 478 | mutex_lock(&dir->d_inode->i_mutex); |
c516865c MS |
479 | if (!sysfs_dirent_exist(parent_sd, attr->name)) |
480 | error = sysfs_make_dirent(parent_sd, NULL, (void *)attr, | |
481 | mode, type); | |
1b1dcc1b | 482 | mutex_unlock(&dir->d_inode->i_mutex); |
1da177e4 LT |
483 | |
484 | return error; | |
485 | } | |
486 | ||
487 | ||
488 | /** | |
489 | * sysfs_create_file - create an attribute file for an object. | |
490 | * @kobj: object we're creating for. | |
491 | * @attr: atrribute descriptor. | |
492 | */ | |
493 | ||
494 | int sysfs_create_file(struct kobject * kobj, const struct attribute * attr) | |
495 | { | |
496 | BUG_ON(!kobj || !kobj->dentry || !attr); | |
497 | ||
498 | return sysfs_add_file(kobj->dentry, attr, SYSFS_KOBJ_ATTR); | |
499 | ||
500 | } | |
501 | ||
502 | ||
dfa87c82 AS |
503 | /** |
504 | * sysfs_add_file_to_group - add an attribute file to a pre-existing group. | |
505 | * @kobj: object we're acting for. | |
506 | * @attr: attribute descriptor. | |
507 | * @group: group name. | |
508 | */ | |
509 | int sysfs_add_file_to_group(struct kobject *kobj, | |
510 | const struct attribute *attr, const char *group) | |
511 | { | |
512 | struct dentry *dir; | |
513 | int error; | |
514 | ||
515 | dir = lookup_one_len(group, kobj->dentry, strlen(group)); | |
516 | if (IS_ERR(dir)) | |
517 | error = PTR_ERR(dir); | |
518 | else { | |
519 | error = sysfs_add_file(dir, attr, SYSFS_KOBJ_ATTR); | |
520 | dput(dir); | |
521 | } | |
522 | return error; | |
523 | } | |
524 | EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); | |
525 | ||
526 | ||
1da177e4 LT |
527 | /** |
528 | * sysfs_update_file - update the modified timestamp on an object attribute. | |
529 | * @kobj: object we're acting for. | |
530 | * @attr: attribute descriptor. | |
1da177e4 LT |
531 | */ |
532 | int sysfs_update_file(struct kobject * kobj, const struct attribute * attr) | |
533 | { | |
534 | struct dentry * dir = kobj->dentry; | |
535 | struct dentry * victim; | |
536 | int res = -ENOENT; | |
537 | ||
1b1dcc1b | 538 | mutex_lock(&dir->d_inode->i_mutex); |
5f45f1a7 | 539 | victim = lookup_one_len(attr->name, dir, strlen(attr->name)); |
1da177e4 LT |
540 | if (!IS_ERR(victim)) { |
541 | /* make sure dentry is really there */ | |
542 | if (victim->d_inode && | |
543 | (victim->d_parent->d_inode == dir->d_inode)) { | |
544 | victim->d_inode->i_mtime = CURRENT_TIME; | |
0eeca283 | 545 | fsnotify_modify(victim); |
1da177e4 LT |
546 | res = 0; |
547 | } else | |
548 | d_drop(victim); | |
549 | ||
550 | /** | |
97a50184 | 551 | * Drop the reference acquired from lookup_one_len() above. |
1da177e4 LT |
552 | */ |
553 | dput(victim); | |
554 | } | |
1b1dcc1b | 555 | mutex_unlock(&dir->d_inode->i_mutex); |
1da177e4 LT |
556 | |
557 | return res; | |
558 | } | |
559 | ||
560 | ||
31e5abe9 KS |
561 | /** |
562 | * sysfs_chmod_file - update the modified mode value on an object attribute. | |
563 | * @kobj: object we're acting for. | |
564 | * @attr: attribute descriptor. | |
565 | * @mode: file permissions. | |
566 | * | |
567 | */ | |
568 | int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode) | |
569 | { | |
570 | struct dentry *dir = kobj->dentry; | |
571 | struct dentry *victim; | |
bc062b1b MS |
572 | struct inode * inode; |
573 | struct iattr newattrs; | |
31e5abe9 KS |
574 | int res = -ENOENT; |
575 | ||
1b1dcc1b | 576 | mutex_lock(&dir->d_inode->i_mutex); |
5f45f1a7 | 577 | victim = lookup_one_len(attr->name, dir, strlen(attr->name)); |
31e5abe9 KS |
578 | if (!IS_ERR(victim)) { |
579 | if (victim->d_inode && | |
580 | (victim->d_parent->d_inode == dir->d_inode)) { | |
bc062b1b | 581 | inode = victim->d_inode; |
1b1dcc1b | 582 | mutex_lock(&inode->i_mutex); |
bc062b1b MS |
583 | newattrs.ia_mode = (mode & S_IALLUGO) | |
584 | (inode->i_mode & ~S_IALLUGO); | |
585 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; | |
586 | res = notify_change(victim, &newattrs); | |
1b1dcc1b | 587 | mutex_unlock(&inode->i_mutex); |
31e5abe9 | 588 | } |
bc062b1b | 589 | dput(victim); |
31e5abe9 | 590 | } |
1b1dcc1b | 591 | mutex_unlock(&dir->d_inode->i_mutex); |
31e5abe9 KS |
592 | |
593 | return res; | |
594 | } | |
595 | EXPORT_SYMBOL_GPL(sysfs_chmod_file); | |
596 | ||
597 | ||
1da177e4 LT |
598 | /** |
599 | * sysfs_remove_file - remove an object attribute. | |
600 | * @kobj: object we're acting for. | |
601 | * @attr: attribute descriptor. | |
602 | * | |
603 | * Hash the attribute name and kill the victim. | |
604 | */ | |
605 | ||
606 | void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr) | |
607 | { | |
94bebf4d | 608 | sysfs_hash_and_remove(kobj->dentry, attr->name); |
1da177e4 LT |
609 | } |
610 | ||
611 | ||
dfa87c82 AS |
612 | /** |
613 | * sysfs_remove_file_from_group - remove an attribute file from a group. | |
614 | * @kobj: object we're acting for. | |
615 | * @attr: attribute descriptor. | |
616 | * @group: group name. | |
617 | */ | |
618 | void sysfs_remove_file_from_group(struct kobject *kobj, | |
619 | const struct attribute *attr, const char *group) | |
620 | { | |
621 | struct dentry *dir; | |
622 | ||
623 | dir = lookup_one_len(group, kobj->dentry, strlen(group)); | |
624 | if (!IS_ERR(dir)) { | |
625 | sysfs_hash_and_remove(dir, attr->name); | |
626 | dput(dir); | |
627 | } | |
628 | } | |
629 | EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); | |
630 | ||
d9a9cdfb AS |
631 | struct sysfs_schedule_callback_struct { |
632 | struct kobject *kobj; | |
633 | void (*func)(void *); | |
634 | void *data; | |
523ded71 | 635 | struct module *owner; |
d9a9cdfb AS |
636 | struct work_struct work; |
637 | }; | |
638 | ||
639 | static void sysfs_schedule_callback_work(struct work_struct *work) | |
640 | { | |
641 | struct sysfs_schedule_callback_struct *ss = container_of(work, | |
642 | struct sysfs_schedule_callback_struct, work); | |
643 | ||
644 | (ss->func)(ss->data); | |
645 | kobject_put(ss->kobj); | |
523ded71 | 646 | module_put(ss->owner); |
d9a9cdfb AS |
647 | kfree(ss); |
648 | } | |
649 | ||
650 | /** | |
651 | * sysfs_schedule_callback - helper to schedule a callback for a kobject | |
652 | * @kobj: object we're acting for. | |
653 | * @func: callback function to invoke later. | |
654 | * @data: argument to pass to @func. | |
523ded71 | 655 | * @owner: module owning the callback code |
d9a9cdfb AS |
656 | * |
657 | * sysfs attribute methods must not unregister themselves or their parent | |
658 | * kobject (which would amount to the same thing). Attempts to do so will | |
659 | * deadlock, since unregistration is mutually exclusive with driver | |
660 | * callbacks. | |
661 | * | |
662 | * Instead methods can call this routine, which will attempt to allocate | |
663 | * and schedule a workqueue request to call back @func with @data as its | |
664 | * argument in the workqueue's process context. @kobj will be pinned | |
665 | * until @func returns. | |
666 | * | |
667 | * Returns 0 if the request was submitted, -ENOMEM if storage could not | |
523ded71 | 668 | * be allocated, -ENODEV if a reference to @owner isn't available. |
d9a9cdfb AS |
669 | */ |
670 | int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), | |
523ded71 | 671 | void *data, struct module *owner) |
d9a9cdfb AS |
672 | { |
673 | struct sysfs_schedule_callback_struct *ss; | |
674 | ||
523ded71 AS |
675 | if (!try_module_get(owner)) |
676 | return -ENODEV; | |
d9a9cdfb | 677 | ss = kmalloc(sizeof(*ss), GFP_KERNEL); |
523ded71 AS |
678 | if (!ss) { |
679 | module_put(owner); | |
d9a9cdfb | 680 | return -ENOMEM; |
523ded71 | 681 | } |
d9a9cdfb AS |
682 | kobject_get(kobj); |
683 | ss->kobj = kobj; | |
684 | ss->func = func; | |
685 | ss->data = data; | |
523ded71 | 686 | ss->owner = owner; |
d9a9cdfb AS |
687 | INIT_WORK(&ss->work, sysfs_schedule_callback_work); |
688 | schedule_work(&ss->work); | |
689 | return 0; | |
690 | } | |
691 | EXPORT_SYMBOL_GPL(sysfs_schedule_callback); | |
692 | ||
dfa87c82 | 693 | |
1da177e4 LT |
694 | EXPORT_SYMBOL_GPL(sysfs_create_file); |
695 | EXPORT_SYMBOL_GPL(sysfs_remove_file); | |
696 | EXPORT_SYMBOL_GPL(sysfs_update_file); |