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