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Commit | Line | Data |
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1da177e4 | 1 | /* |
6d66f5cd TH |
2 | * fs/sysfs/file.c - sysfs regular (text) file implementation |
3 | * | |
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. | |
9 | * | |
10 | * Please see Documentation/filesystems/sysfs.txt for more information. | |
1da177e4 LT |
11 | */ |
12 | ||
13 | #include <linux/module.h> | |
1da177e4 | 14 | #include <linux/kobject.h> |
815d2d50 | 15 | #include <linux/kallsyms.h> |
c6f87733 | 16 | #include <linux/slab.h> |
5f45f1a7 | 17 | #include <linux/namei.h> |
4508a7a7 | 18 | #include <linux/poll.h> |
94bebf4d | 19 | #include <linux/list.h> |
52e8c209 | 20 | #include <linux/mutex.h> |
1da177e4 | 21 | #include <asm/uaccess.h> |
1da177e4 LT |
22 | |
23 | #include "sysfs.h" | |
24 | ||
85a4ffad TH |
25 | /* |
26 | * There's one sysfs_buffer for each open file and one | |
27 | * sysfs_open_dirent for each sysfs_dirent with one or more open | |
28 | * files. | |
29 | * | |
30 | * filp->private_data points to sysfs_buffer and | |
31 | * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open | |
32 | * is protected by sysfs_open_dirent_lock. | |
33 | */ | |
d7b37889 | 34 | static DEFINE_SPINLOCK(sysfs_open_dirent_lock); |
85a4ffad TH |
35 | |
36 | struct sysfs_open_dirent { | |
37 | atomic_t refcnt; | |
a4e8b912 TH |
38 | atomic_t event; |
39 | wait_queue_head_t poll; | |
85a4ffad TH |
40 | struct list_head buffers; /* goes through sysfs_buffer.list */ |
41 | }; | |
42 | ||
73107cb3 TH |
43 | struct sysfs_buffer { |
44 | size_t count; | |
45 | loff_t pos; | |
46 | char * page; | |
47 | struct sysfs_ops * ops; | |
52e8c209 | 48 | struct mutex mutex; |
73107cb3 TH |
49 | int needs_read_fill; |
50 | int event; | |
85a4ffad | 51 | struct list_head list; |
73107cb3 | 52 | }; |
1da177e4 LT |
53 | |
54 | /** | |
55 | * fill_read_buffer - allocate and fill buffer from object. | |
56 | * @dentry: dentry pointer. | |
57 | * @buffer: data buffer for file. | |
58 | * | |
59 | * Allocate @buffer->page, if it hasn't been already, then call the | |
60 | * kobject's show() method to fill the buffer with this attribute's | |
61 | * data. | |
82244b16 ON |
62 | * This is called only once, on the file's first read unless an error |
63 | * is returned. | |
1da177e4 LT |
64 | */ |
65 | static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer) | |
66 | { | |
0ab66088 | 67 | struct sysfs_dirent *attr_sd = dentry->d_fsdata; |
b1fc3d61 | 68 | struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; |
1da177e4 LT |
69 | struct sysfs_ops * ops = buffer->ops; |
70 | int ret = 0; | |
71 | ssize_t count; | |
72 | ||
73 | if (!buffer->page) | |
74 | buffer->page = (char *) get_zeroed_page(GFP_KERNEL); | |
75 | if (!buffer->page) | |
76 | return -ENOMEM; | |
77 | ||
0ab66088 TH |
78 | /* need attr_sd for attr and ops, its parent for kobj */ |
79 | if (!sysfs_get_active_two(attr_sd)) | |
80 | return -ENODEV; | |
81 | ||
a4e8b912 | 82 | buffer->event = atomic_read(&attr_sd->s_attr.open->event); |
b1fc3d61 | 83 | count = ops->show(kobj, attr_sd->s_attr.attr, buffer->page); |
0ab66088 TH |
84 | |
85 | sysfs_put_active_two(attr_sd); | |
86 | ||
8118a859 MX |
87 | /* |
88 | * The code works fine with PAGE_SIZE return but it's likely to | |
89 | * indicate truncated result or overflow in normal use cases. | |
90 | */ | |
815d2d50 AM |
91 | if (count >= (ssize_t)PAGE_SIZE) { |
92 | print_symbol("fill_read_buffer: %s returned bad count\n", | |
93 | (unsigned long)ops->show); | |
94 | /* Try to struggle along */ | |
95 | count = PAGE_SIZE - 1; | |
96 | } | |
82244b16 ON |
97 | if (count >= 0) { |
98 | buffer->needs_read_fill = 0; | |
1da177e4 | 99 | buffer->count = count; |
82244b16 | 100 | } else { |
1da177e4 | 101 | ret = count; |
82244b16 | 102 | } |
1da177e4 LT |
103 | return ret; |
104 | } | |
105 | ||
1da177e4 LT |
106 | /** |
107 | * sysfs_read_file - read an attribute. | |
108 | * @file: file pointer. | |
109 | * @buf: buffer to fill. | |
110 | * @count: number of bytes to read. | |
111 | * @ppos: starting offset in file. | |
112 | * | |
113 | * Userspace wants to read an attribute file. The attribute descriptor | |
114 | * is in the file's ->d_fsdata. The target object is in the directory's | |
115 | * ->d_fsdata. | |
116 | * | |
117 | * We call fill_read_buffer() to allocate and fill the buffer from the | |
118 | * object's show() method exactly once (if the read is happening from | |
119 | * the beginning of the file). That should fill the entire buffer with | |
120 | * all the data the object has to offer for that attribute. | |
121 | * We then call flush_read_buffer() to copy the buffer to userspace | |
122 | * in the increments specified. | |
123 | */ | |
124 | ||
125 | static ssize_t | |
126 | sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
127 | { | |
128 | struct sysfs_buffer * buffer = file->private_data; | |
129 | ssize_t retval = 0; | |
130 | ||
52e8c209 | 131 | mutex_lock(&buffer->mutex); |
1da177e4 | 132 | if (buffer->needs_read_fill) { |
73107cb3 | 133 | retval = fill_read_buffer(file->f_path.dentry,buffer); |
e7b0d26a | 134 | if (retval) |
1da177e4 LT |
135 | goto out; |
136 | } | |
5c1fdf41 ZB |
137 | pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n", |
138 | __FUNCTION__, count, *ppos, buffer->page); | |
92f4c701 AM |
139 | retval = simple_read_from_buffer(buf, count, ppos, buffer->page, |
140 | buffer->count); | |
1da177e4 | 141 | out: |
52e8c209 | 142 | mutex_unlock(&buffer->mutex); |
1da177e4 LT |
143 | return retval; |
144 | } | |
145 | ||
1da177e4 LT |
146 | /** |
147 | * fill_write_buffer - copy buffer from userspace. | |
148 | * @buffer: data buffer for file. | |
67be2dd1 | 149 | * @buf: data from user. |
1da177e4 LT |
150 | * @count: number of bytes in @userbuf. |
151 | * | |
152 | * Allocate @buffer->page if it hasn't been already, then | |
153 | * copy the user-supplied buffer into it. | |
154 | */ | |
155 | ||
156 | static int | |
157 | fill_write_buffer(struct sysfs_buffer * buffer, const char __user * buf, size_t count) | |
158 | { | |
159 | int error; | |
160 | ||
161 | if (!buffer->page) | |
162 | buffer->page = (char *)get_zeroed_page(GFP_KERNEL); | |
163 | if (!buffer->page) | |
164 | return -ENOMEM; | |
165 | ||
166 | if (count >= PAGE_SIZE) | |
6e0dd741 | 167 | count = PAGE_SIZE - 1; |
1da177e4 LT |
168 | error = copy_from_user(buffer->page,buf,count); |
169 | buffer->needs_read_fill = 1; | |
035ed7a4 TM |
170 | /* if buf is assumed to contain a string, terminate it by \0, |
171 | so e.g. sscanf() can scan the string easily */ | |
172 | buffer->page[count] = 0; | |
1da177e4 LT |
173 | return error ? -EFAULT : count; |
174 | } | |
175 | ||
176 | ||
177 | /** | |
178 | * flush_write_buffer - push buffer to kobject. | |
3d41088f | 179 | * @dentry: dentry to the attribute |
1da177e4 | 180 | * @buffer: data buffer for file. |
3d41088f | 181 | * @count: number of bytes |
1da177e4 LT |
182 | * |
183 | * Get the correct pointers for the kobject and the attribute we're | |
184 | * dealing with, then call the store() method for the attribute, | |
185 | * passing the buffer that we acquired in fill_write_buffer(). | |
186 | */ | |
187 | ||
0ab66088 | 188 | static int |
1da177e4 LT |
189 | flush_write_buffer(struct dentry * dentry, struct sysfs_buffer * buffer, size_t count) |
190 | { | |
3e519038 | 191 | struct sysfs_dirent *attr_sd = dentry->d_fsdata; |
b1fc3d61 | 192 | struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; |
1da177e4 | 193 | struct sysfs_ops * ops = buffer->ops; |
0ab66088 TH |
194 | int rc; |
195 | ||
196 | /* need attr_sd for attr and ops, its parent for kobj */ | |
197 | if (!sysfs_get_active_two(attr_sd)) | |
198 | return -ENODEV; | |
199 | ||
b1fc3d61 | 200 | rc = ops->store(kobj, attr_sd->s_attr.attr, buffer->page, count); |
0ab66088 TH |
201 | |
202 | sysfs_put_active_two(attr_sd); | |
1da177e4 | 203 | |
0ab66088 | 204 | return rc; |
1da177e4 LT |
205 | } |
206 | ||
207 | ||
208 | /** | |
209 | * sysfs_write_file - write an attribute. | |
210 | * @file: file pointer | |
211 | * @buf: data to write | |
212 | * @count: number of bytes | |
213 | * @ppos: starting offset | |
214 | * | |
215 | * Similar to sysfs_read_file(), though working in the opposite direction. | |
216 | * We allocate and fill the data from the user in fill_write_buffer(), | |
217 | * then push it to the kobject in flush_write_buffer(). | |
218 | * There is no easy way for us to know if userspace is only doing a partial | |
219 | * write, so we don't support them. We expect the entire buffer to come | |
220 | * on the first write. | |
221 | * Hint: if you're writing a value, first read the file, modify only the | |
222 | * the value you're changing, then write entire buffer back. | |
223 | */ | |
224 | ||
225 | static ssize_t | |
226 | sysfs_write_file(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
227 | { | |
228 | struct sysfs_buffer * buffer = file->private_data; | |
229 | ssize_t len; | |
230 | ||
52e8c209 | 231 | mutex_lock(&buffer->mutex); |
1da177e4 LT |
232 | len = fill_write_buffer(buffer, buf, count); |
233 | if (len > 0) | |
f427f5d5 | 234 | len = flush_write_buffer(file->f_path.dentry, buffer, len); |
1da177e4 LT |
235 | if (len > 0) |
236 | *ppos += len; | |
52e8c209 | 237 | mutex_unlock(&buffer->mutex); |
1da177e4 LT |
238 | return len; |
239 | } | |
240 | ||
85a4ffad TH |
241 | /** |
242 | * sysfs_get_open_dirent - get or create sysfs_open_dirent | |
243 | * @sd: target sysfs_dirent | |
244 | * @buffer: sysfs_buffer for this instance of open | |
245 | * | |
246 | * If @sd->s_attr.open exists, increment its reference count; | |
247 | * otherwise, create one. @buffer is chained to the buffers | |
248 | * list. | |
249 | * | |
250 | * LOCKING: | |
251 | * Kernel thread context (may sleep). | |
252 | * | |
253 | * RETURNS: | |
254 | * 0 on success, -errno on failure. | |
255 | */ | |
256 | static int sysfs_get_open_dirent(struct sysfs_dirent *sd, | |
257 | struct sysfs_buffer *buffer) | |
258 | { | |
259 | struct sysfs_open_dirent *od, *new_od = NULL; | |
260 | ||
261 | retry: | |
262 | spin_lock(&sysfs_open_dirent_lock); | |
263 | ||
264 | if (!sd->s_attr.open && new_od) { | |
265 | sd->s_attr.open = new_od; | |
266 | new_od = NULL; | |
267 | } | |
268 | ||
269 | od = sd->s_attr.open; | |
270 | if (od) { | |
271 | atomic_inc(&od->refcnt); | |
272 | list_add_tail(&buffer->list, &od->buffers); | |
273 | } | |
274 | ||
275 | spin_unlock(&sysfs_open_dirent_lock); | |
276 | ||
277 | if (od) { | |
278 | kfree(new_od); | |
279 | return 0; | |
280 | } | |
281 | ||
282 | /* not there, initialize a new one and retry */ | |
283 | new_od = kmalloc(sizeof(*new_od), GFP_KERNEL); | |
284 | if (!new_od) | |
285 | return -ENOMEM; | |
286 | ||
287 | atomic_set(&new_od->refcnt, 0); | |
a4e8b912 TH |
288 | atomic_set(&new_od->event, 1); |
289 | init_waitqueue_head(&new_od->poll); | |
85a4ffad TH |
290 | INIT_LIST_HEAD(&new_od->buffers); |
291 | goto retry; | |
292 | } | |
293 | ||
294 | /** | |
295 | * sysfs_put_open_dirent - put sysfs_open_dirent | |
296 | * @sd: target sysfs_dirent | |
297 | * @buffer: associated sysfs_buffer | |
298 | * | |
299 | * Put @sd->s_attr.open and unlink @buffer from the buffers list. | |
300 | * If reference count reaches zero, disassociate and free it. | |
301 | * | |
302 | * LOCKING: | |
303 | * None. | |
304 | */ | |
305 | static void sysfs_put_open_dirent(struct sysfs_dirent *sd, | |
306 | struct sysfs_buffer *buffer) | |
307 | { | |
308 | struct sysfs_open_dirent *od = sd->s_attr.open; | |
309 | ||
310 | spin_lock(&sysfs_open_dirent_lock); | |
311 | ||
312 | list_del(&buffer->list); | |
313 | if (atomic_dec_and_test(&od->refcnt)) | |
314 | sd->s_attr.open = NULL; | |
315 | else | |
316 | od = NULL; | |
317 | ||
318 | spin_unlock(&sysfs_open_dirent_lock); | |
319 | ||
320 | kfree(od); | |
321 | } | |
322 | ||
94bebf4d | 323 | static int sysfs_open_file(struct inode *inode, struct file *file) |
1da177e4 | 324 | { |
3e519038 | 325 | struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; |
b1fc3d61 | 326 | struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; |
000f2a4d KS |
327 | struct sysfs_buffer *buffer; |
328 | struct sysfs_ops *ops; | |
329 | int error = -EACCES; | |
1da177e4 | 330 | |
0ab66088 TH |
331 | /* need attr_sd for attr and ops, its parent for kobj */ |
332 | if (!sysfs_get_active_two(attr_sd)) | |
333 | return -ENODEV; | |
1da177e4 | 334 | |
000f2a4d KS |
335 | /* every kobject with an attribute needs a ktype assigned */ |
336 | if (kobj->ktype && kobj->ktype->sysfs_ops) | |
1da177e4 | 337 | ops = kobj->ktype->sysfs_ops; |
000f2a4d KS |
338 | else { |
339 | printk(KERN_ERR "missing sysfs attribute operations for " | |
340 | "kobject: %s\n", kobject_name(kobj)); | |
341 | WARN_ON(1); | |
7b595756 | 342 | goto err_out; |
000f2a4d | 343 | } |
1da177e4 LT |
344 | |
345 | /* File needs write support. | |
346 | * The inode's perms must say it's ok, | |
347 | * and we must have a store method. | |
348 | */ | |
349 | if (file->f_mode & FMODE_WRITE) { | |
1da177e4 | 350 | if (!(inode->i_mode & S_IWUGO) || !ops->store) |
7b595756 | 351 | goto err_out; |
1da177e4 LT |
352 | } |
353 | ||
354 | /* File needs read support. | |
355 | * The inode's perms must say it's ok, and we there | |
356 | * must be a show method for it. | |
357 | */ | |
358 | if (file->f_mode & FMODE_READ) { | |
359 | if (!(inode->i_mode & S_IRUGO) || !ops->show) | |
7b595756 | 360 | goto err_out; |
1da177e4 LT |
361 | } |
362 | ||
363 | /* No error? Great, allocate a buffer for the file, and store it | |
364 | * it in file->private_data for easy access. | |
365 | */ | |
0ab66088 | 366 | error = -ENOMEM; |
58d49283 | 367 | buffer = kzalloc(sizeof(struct sysfs_buffer), GFP_KERNEL); |
0ab66088 | 368 | if (!buffer) |
7b595756 | 369 | goto err_out; |
1da177e4 | 370 | |
52e8c209 | 371 | mutex_init(&buffer->mutex); |
0ab66088 TH |
372 | buffer->needs_read_fill = 1; |
373 | buffer->ops = ops; | |
0ab66088 TH |
374 | file->private_data = buffer; |
375 | ||
85a4ffad TH |
376 | /* make sure we have open dirent struct */ |
377 | error = sysfs_get_open_dirent(attr_sd, buffer); | |
378 | if (error) | |
379 | goto err_free; | |
380 | ||
b05f0548 | 381 | /* open succeeded, put active references */ |
0ab66088 | 382 | sysfs_put_active_two(attr_sd); |
0ab66088 TH |
383 | return 0; |
384 | ||
85a4ffad TH |
385 | err_free: |
386 | kfree(buffer); | |
7b595756 | 387 | err_out: |
0ab66088 | 388 | sysfs_put_active_two(attr_sd); |
1da177e4 LT |
389 | return error; |
390 | } | |
391 | ||
85a4ffad | 392 | static int sysfs_release(struct inode *inode, struct file *filp) |
1da177e4 | 393 | { |
85a4ffad | 394 | struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata; |
73107cb3 | 395 | struct sysfs_buffer *buffer = filp->private_data; |
1da177e4 | 396 | |
85a4ffad TH |
397 | sysfs_put_open_dirent(sd, buffer); |
398 | ||
50ab1a72 TH |
399 | if (buffer->page) |
400 | free_page((unsigned long)buffer->page); | |
401 | kfree(buffer); | |
402 | ||
1da177e4 LT |
403 | return 0; |
404 | } | |
405 | ||
4508a7a7 N |
406 | /* Sysfs attribute files are pollable. The idea is that you read |
407 | * the content and then you use 'poll' or 'select' to wait for | |
408 | * the content to change. When the content changes (assuming the | |
409 | * manager for the kobject supports notification), poll will | |
410 | * return POLLERR|POLLPRI, and select will return the fd whether | |
411 | * it is waiting for read, write, or exceptions. | |
412 | * Once poll/select indicates that the value has changed, you | |
413 | * need to close and re-open the file, as simply seeking and reading | |
414 | * again will not get new data, or reset the state of 'poll'. | |
415 | * Reminder: this only works for attributes which actively support | |
416 | * it, and it is not possible to test an attribute from userspace | |
a93720ee | 417 | * to see if it supports poll (Neither 'poll' nor 'select' return |
4508a7a7 N |
418 | * an appropriate error code). When in doubt, set a suitable timeout value. |
419 | */ | |
420 | static unsigned int sysfs_poll(struct file *filp, poll_table *wait) | |
421 | { | |
422 | struct sysfs_buffer * buffer = filp->private_data; | |
0ab66088 | 423 | struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata; |
a4e8b912 | 424 | struct sysfs_open_dirent *od = attr_sd->s_attr.open; |
0ab66088 TH |
425 | |
426 | /* need parent for the kobj, grab both */ | |
427 | if (!sysfs_get_active_two(attr_sd)) | |
428 | goto trigger; | |
4508a7a7 | 429 | |
a4e8b912 | 430 | poll_wait(filp, &od->poll, wait); |
4508a7a7 | 431 | |
0ab66088 TH |
432 | sysfs_put_active_two(attr_sd); |
433 | ||
a4e8b912 | 434 | if (buffer->event != atomic_read(&od->event)) |
0ab66088 | 435 | goto trigger; |
4508a7a7 | 436 | |
0ab66088 TH |
437 | return 0; |
438 | ||
439 | trigger: | |
440 | buffer->needs_read_fill = 1; | |
441 | return POLLERR|POLLPRI; | |
4508a7a7 N |
442 | } |
443 | ||
51225039 | 444 | void sysfs_notify(struct kobject *k, char *dir, char *attr) |
4508a7a7 | 445 | { |
51225039 | 446 | struct sysfs_dirent *sd = k->sd; |
4508a7a7 | 447 | |
51225039 TH |
448 | mutex_lock(&sysfs_mutex); |
449 | ||
450 | if (sd && dir) | |
451 | sd = sysfs_find_dirent(sd, dir); | |
452 | if (sd && attr) | |
453 | sd = sysfs_find_dirent(sd, attr); | |
454 | if (sd) { | |
a4e8b912 TH |
455 | struct sysfs_open_dirent *od; |
456 | ||
457 | spin_lock(&sysfs_open_dirent_lock); | |
458 | ||
459 | od = sd->s_attr.open; | |
460 | if (od) { | |
461 | atomic_inc(&od->event); | |
462 | wake_up_interruptible(&od->poll); | |
463 | } | |
464 | ||
465 | spin_unlock(&sysfs_open_dirent_lock); | |
4508a7a7 | 466 | } |
51225039 TH |
467 | |
468 | mutex_unlock(&sysfs_mutex); | |
4508a7a7 N |
469 | } |
470 | EXPORT_SYMBOL_GPL(sysfs_notify); | |
471 | ||
4b6f5d20 | 472 | const struct file_operations sysfs_file_operations = { |
1da177e4 LT |
473 | .read = sysfs_read_file, |
474 | .write = sysfs_write_file, | |
475 | .llseek = generic_file_llseek, | |
476 | .open = sysfs_open_file, | |
477 | .release = sysfs_release, | |
4508a7a7 | 478 | .poll = sysfs_poll, |
1da177e4 LT |
479 | }; |
480 | ||
481 | ||
608e266a TH |
482 | int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr, |
483 | int type) | |
1da177e4 | 484 | { |
1da177e4 | 485 | umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG; |
fb6896da | 486 | struct sysfs_addrm_cxt acxt; |
a26cd722 | 487 | struct sysfs_dirent *sd; |
23dc2799 | 488 | int rc; |
1da177e4 | 489 | |
3007e997 TH |
490 | sd = sysfs_new_dirent(attr->name, mode, type); |
491 | if (!sd) | |
492 | return -ENOMEM; | |
b1fc3d61 | 493 | sd->s_attr.attr = (void *)attr; |
1da177e4 | 494 | |
fb6896da | 495 | sysfs_addrm_start(&acxt, dir_sd); |
23dc2799 TH |
496 | rc = sysfs_add_one(&acxt, sd); |
497 | sysfs_addrm_finish(&acxt); | |
a26cd722 | 498 | |
23dc2799 | 499 | if (rc) |
967e35dc | 500 | sysfs_put(sd); |
3007e997 | 501 | |
23dc2799 | 502 | return rc; |
1da177e4 LT |
503 | } |
504 | ||
505 | ||
506 | /** | |
507 | * sysfs_create_file - create an attribute file for an object. | |
508 | * @kobj: object we're creating for. | |
3932bf60 | 509 | * @attr: attribute descriptor. |
1da177e4 LT |
510 | */ |
511 | ||
512 | int sysfs_create_file(struct kobject * kobj, const struct attribute * attr) | |
513 | { | |
608e266a | 514 | BUG_ON(!kobj || !kobj->sd || !attr); |
1da177e4 | 515 | |
608e266a | 516 | return sysfs_add_file(kobj->sd, attr, SYSFS_KOBJ_ATTR); |
1da177e4 LT |
517 | |
518 | } | |
519 | ||
520 | ||
dfa87c82 AS |
521 | /** |
522 | * sysfs_add_file_to_group - add an attribute file to a pre-existing group. | |
523 | * @kobj: object we're acting for. | |
524 | * @attr: attribute descriptor. | |
525 | * @group: group name. | |
526 | */ | |
527 | int sysfs_add_file_to_group(struct kobject *kobj, | |
528 | const struct attribute *attr, const char *group) | |
529 | { | |
608e266a | 530 | struct sysfs_dirent *dir_sd; |
dfa87c82 AS |
531 | int error; |
532 | ||
11f24fbd JB |
533 | if (group) |
534 | dir_sd = sysfs_get_dirent(kobj->sd, group); | |
535 | else | |
536 | dir_sd = sysfs_get(kobj->sd); | |
537 | ||
608e266a TH |
538 | if (!dir_sd) |
539 | return -ENOENT; | |
540 | ||
541 | error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR); | |
542 | sysfs_put(dir_sd); | |
543 | ||
dfa87c82 AS |
544 | return error; |
545 | } | |
546 | EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); | |
547 | ||
31e5abe9 KS |
548 | /** |
549 | * sysfs_chmod_file - update the modified mode value on an object attribute. | |
550 | * @kobj: object we're acting for. | |
551 | * @attr: attribute descriptor. | |
552 | * @mode: file permissions. | |
553 | * | |
554 | */ | |
555 | int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode) | |
556 | { | |
51225039 TH |
557 | struct sysfs_dirent *victim_sd = NULL; |
558 | struct dentry *victim = NULL; | |
bc062b1b MS |
559 | struct inode * inode; |
560 | struct iattr newattrs; | |
51225039 TH |
561 | int rc; |
562 | ||
563 | rc = -ENOENT; | |
564 | victim_sd = sysfs_get_dirent(kobj->sd, attr->name); | |
565 | if (!victim_sd) | |
566 | goto out; | |
567 | ||
932ea2e3 | 568 | mutex_lock(&sysfs_rename_mutex); |
51225039 | 569 | victim = sysfs_get_dentry(victim_sd); |
932ea2e3 | 570 | mutex_unlock(&sysfs_rename_mutex); |
51225039 TH |
571 | if (IS_ERR(victim)) { |
572 | rc = PTR_ERR(victim); | |
573 | victim = NULL; | |
574 | goto out; | |
31e5abe9 | 575 | } |
31e5abe9 | 576 | |
51225039 | 577 | inode = victim->d_inode; |
f88123ea | 578 | |
51225039 | 579 | mutex_lock(&inode->i_mutex); |
f88123ea | 580 | |
51225039 TH |
581 | newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); |
582 | newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; | |
583 | rc = notify_change(victim, &newattrs); | |
f88123ea TH |
584 | |
585 | if (rc == 0) { | |
586 | mutex_lock(&sysfs_mutex); | |
587 | victim_sd->s_mode = newattrs.ia_mode; | |
588 | mutex_unlock(&sysfs_mutex); | |
589 | } | |
590 | ||
51225039 TH |
591 | mutex_unlock(&inode->i_mutex); |
592 | out: | |
593 | dput(victim); | |
594 | sysfs_put(victim_sd); | |
595 | return rc; | |
31e5abe9 KS |
596 | } |
597 | EXPORT_SYMBOL_GPL(sysfs_chmod_file); | |
598 | ||
599 | ||
1da177e4 LT |
600 | /** |
601 | * sysfs_remove_file - remove an object attribute. | |
602 | * @kobj: object we're acting for. | |
603 | * @attr: attribute descriptor. | |
604 | * | |
605 | * Hash the attribute name and kill the victim. | |
606 | */ | |
607 | ||
608 | void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr) | |
609 | { | |
608e266a | 610 | sysfs_hash_and_remove(kobj->sd, attr->name); |
1da177e4 LT |
611 | } |
612 | ||
613 | ||
dfa87c82 AS |
614 | /** |
615 | * sysfs_remove_file_from_group - remove an attribute file from a group. | |
616 | * @kobj: object we're acting for. | |
617 | * @attr: attribute descriptor. | |
618 | * @group: group name. | |
619 | */ | |
620 | void sysfs_remove_file_from_group(struct kobject *kobj, | |
621 | const struct attribute *attr, const char *group) | |
622 | { | |
608e266a | 623 | struct sysfs_dirent *dir_sd; |
dfa87c82 | 624 | |
11f24fbd JB |
625 | if (group) |
626 | dir_sd = sysfs_get_dirent(kobj->sd, group); | |
627 | else | |
628 | dir_sd = sysfs_get(kobj->sd); | |
608e266a TH |
629 | if (dir_sd) { |
630 | sysfs_hash_and_remove(dir_sd, attr->name); | |
631 | sysfs_put(dir_sd); | |
dfa87c82 AS |
632 | } |
633 | } | |
634 | EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); | |
635 | ||
d9a9cdfb AS |
636 | struct sysfs_schedule_callback_struct { |
637 | struct kobject *kobj; | |
638 | void (*func)(void *); | |
639 | void *data; | |
523ded71 | 640 | struct module *owner; |
d9a9cdfb AS |
641 | struct work_struct work; |
642 | }; | |
643 | ||
644 | static void sysfs_schedule_callback_work(struct work_struct *work) | |
645 | { | |
646 | struct sysfs_schedule_callback_struct *ss = container_of(work, | |
647 | struct sysfs_schedule_callback_struct, work); | |
648 | ||
649 | (ss->func)(ss->data); | |
650 | kobject_put(ss->kobj); | |
523ded71 | 651 | module_put(ss->owner); |
d9a9cdfb AS |
652 | kfree(ss); |
653 | } | |
654 | ||
655 | /** | |
656 | * sysfs_schedule_callback - helper to schedule a callback for a kobject | |
657 | * @kobj: object we're acting for. | |
658 | * @func: callback function to invoke later. | |
659 | * @data: argument to pass to @func. | |
523ded71 | 660 | * @owner: module owning the callback code |
d9a9cdfb AS |
661 | * |
662 | * sysfs attribute methods must not unregister themselves or their parent | |
663 | * kobject (which would amount to the same thing). Attempts to do so will | |
664 | * deadlock, since unregistration is mutually exclusive with driver | |
665 | * callbacks. | |
666 | * | |
667 | * Instead methods can call this routine, which will attempt to allocate | |
668 | * and schedule a workqueue request to call back @func with @data as its | |
669 | * argument in the workqueue's process context. @kobj will be pinned | |
670 | * until @func returns. | |
671 | * | |
672 | * Returns 0 if the request was submitted, -ENOMEM if storage could not | |
523ded71 | 673 | * be allocated, -ENODEV if a reference to @owner isn't available. |
d9a9cdfb AS |
674 | */ |
675 | int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), | |
523ded71 | 676 | void *data, struct module *owner) |
d9a9cdfb AS |
677 | { |
678 | struct sysfs_schedule_callback_struct *ss; | |
679 | ||
523ded71 AS |
680 | if (!try_module_get(owner)) |
681 | return -ENODEV; | |
d9a9cdfb | 682 | ss = kmalloc(sizeof(*ss), GFP_KERNEL); |
523ded71 AS |
683 | if (!ss) { |
684 | module_put(owner); | |
d9a9cdfb | 685 | return -ENOMEM; |
523ded71 | 686 | } |
d9a9cdfb AS |
687 | kobject_get(kobj); |
688 | ss->kobj = kobj; | |
689 | ss->func = func; | |
690 | ss->data = data; | |
523ded71 | 691 | ss->owner = owner; |
d9a9cdfb AS |
692 | INIT_WORK(&ss->work, sysfs_schedule_callback_work); |
693 | schedule_work(&ss->work); | |
694 | return 0; | |
695 | } | |
696 | EXPORT_SYMBOL_GPL(sysfs_schedule_callback); | |
697 | ||
dfa87c82 | 698 | |
1da177e4 LT |
699 | EXPORT_SYMBOL_GPL(sysfs_create_file); |
700 | EXPORT_SYMBOL_GPL(sysfs_remove_file); |