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> |
c6f87733 | 16 | #include <linux/slab.h> |
93265d13 | 17 | #include <linux/fsnotify.h> |
5f45f1a7 | 18 | #include <linux/namei.h> |
4508a7a7 | 19 | #include <linux/poll.h> |
94bebf4d | 20 | #include <linux/list.h> |
52e8c209 | 21 | #include <linux/mutex.h> |
ae87221d | 22 | #include <linux/limits.h> |
060cc749 | 23 | #include <linux/uaccess.h> |
1da177e4 LT |
24 | |
25 | #include "sysfs.h" | |
26 | ||
85a4ffad TH |
27 | /* |
28 | * There's one sysfs_buffer for each open file and one | |
29 | * sysfs_open_dirent for each sysfs_dirent with one or more open | |
30 | * files. | |
31 | * | |
32 | * filp->private_data points to sysfs_buffer and | |
33 | * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open | |
34 | * is protected by sysfs_open_dirent_lock. | |
35 | */ | |
d7b37889 | 36 | static DEFINE_SPINLOCK(sysfs_open_dirent_lock); |
85a4ffad TH |
37 | |
38 | struct sysfs_open_dirent { | |
39 | atomic_t refcnt; | |
a4e8b912 TH |
40 | atomic_t event; |
41 | wait_queue_head_t poll; | |
85a4ffad TH |
42 | struct list_head buffers; /* goes through sysfs_buffer.list */ |
43 | }; | |
44 | ||
73107cb3 TH |
45 | struct sysfs_buffer { |
46 | size_t count; | |
47 | loff_t pos; | |
1b18dc2b GKH |
48 | char *page; |
49 | const struct sysfs_ops *ops; | |
52e8c209 | 50 | struct mutex mutex; |
73107cb3 TH |
51 | int needs_read_fill; |
52 | int event; | |
85a4ffad | 53 | struct list_head list; |
73107cb3 | 54 | }; |
1da177e4 LT |
55 | |
56 | /** | |
57 | * fill_read_buffer - allocate and fill buffer from object. | |
58 | * @dentry: dentry pointer. | |
59 | * @buffer: data buffer for file. | |
60 | * | |
61 | * Allocate @buffer->page, if it hasn't been already, then call the | |
ab9bf4be GKH |
62 | * kobject's show() method to fill the buffer with this attribute's |
63 | * data. | |
82244b16 ON |
64 | * This is called only once, on the file's first read unless an error |
65 | * is returned. | |
1da177e4 | 66 | */ |
1b18dc2b | 67 | static int fill_read_buffer(struct dentry *dentry, struct sysfs_buffer *buffer) |
1da177e4 | 68 | { |
0ab66088 | 69 | struct sysfs_dirent *attr_sd = dentry->d_fsdata; |
b1fc3d61 | 70 | struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; |
1b18dc2b | 71 | const struct sysfs_ops *ops = buffer->ops; |
1da177e4 LT |
72 | int ret = 0; |
73 | ssize_t count; | |
74 | ||
75 | if (!buffer->page) | |
76 | buffer->page = (char *) get_zeroed_page(GFP_KERNEL); | |
77 | if (!buffer->page) | |
78 | return -ENOMEM; | |
79 | ||
0ab66088 | 80 | /* need attr_sd for attr and ops, its parent for kobj */ |
e72ceb8c | 81 | if (!sysfs_get_active(attr_sd)) |
0ab66088 TH |
82 | return -ENODEV; |
83 | ||
a4e8b912 | 84 | buffer->event = atomic_read(&attr_sd->s_attr.open->event); |
b1fc3d61 | 85 | count = ops->show(kobj, attr_sd->s_attr.attr, buffer->page); |
0ab66088 | 86 | |
e72ceb8c | 87 | sysfs_put_active(attr_sd); |
0ab66088 | 88 | |
8118a859 MX |
89 | /* |
90 | * The code works fine with PAGE_SIZE return but it's likely to | |
91 | * indicate truncated result or overflow in normal use cases. | |
92 | */ | |
815d2d50 AM |
93 | if (count >= (ssize_t)PAGE_SIZE) { |
94 | print_symbol("fill_read_buffer: %s returned bad count\n", | |
95 | (unsigned long)ops->show); | |
96 | /* Try to struggle along */ | |
97 | count = PAGE_SIZE - 1; | |
98 | } | |
82244b16 ON |
99 | if (count >= 0) { |
100 | buffer->needs_read_fill = 0; | |
1da177e4 | 101 | buffer->count = count; |
82244b16 | 102 | } else { |
1da177e4 | 103 | ret = count; |
82244b16 | 104 | } |
1da177e4 LT |
105 | return ret; |
106 | } | |
107 | ||
1da177e4 | 108 | /** |
ab9bf4be | 109 | * sysfs_read_file - read an attribute. |
1da177e4 LT |
110 | * @file: file pointer. |
111 | * @buf: buffer to fill. | |
112 | * @count: number of bytes to read. | |
113 | * @ppos: starting offset in file. | |
114 | * | |
115 | * Userspace wants to read an attribute file. The attribute descriptor | |
116 | * is in the file's ->d_fsdata. The target object is in the directory's | |
117 | * ->d_fsdata. | |
118 | * | |
119 | * We call fill_read_buffer() to allocate and fill the buffer from the | |
120 | * object's show() method exactly once (if the read is happening from | |
121 | * the beginning of the file). That should fill the entire buffer with | |
122 | * all the data the object has to offer for that attribute. | |
123 | * We then call flush_read_buffer() to copy the buffer to userspace | |
124 | * in the increments specified. | |
125 | */ | |
126 | ||
127 | static ssize_t | |
128 | sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
129 | { | |
1b18dc2b | 130 | struct sysfs_buffer *buffer = file->private_data; |
1da177e4 LT |
131 | ssize_t retval = 0; |
132 | ||
52e8c209 | 133 | mutex_lock(&buffer->mutex); |
2424b5dd | 134 | if (buffer->needs_read_fill || *ppos == 0) { |
1b18dc2b | 135 | retval = fill_read_buffer(file->f_path.dentry, buffer); |
e7b0d26a | 136 | if (retval) |
1da177e4 LT |
137 | goto out; |
138 | } | |
5c1fdf41 | 139 | pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n", |
8e24eea7 | 140 | __func__, count, *ppos, buffer->page); |
92f4c701 AM |
141 | retval = simple_read_from_buffer(buf, count, ppos, buffer->page, |
142 | buffer->count); | |
1da177e4 | 143 | out: |
52e8c209 | 144 | mutex_unlock(&buffer->mutex); |
1da177e4 LT |
145 | return retval; |
146 | } | |
147 | ||
1da177e4 LT |
148 | /** |
149 | * fill_write_buffer - copy buffer from userspace. | |
150 | * @buffer: data buffer for file. | |
67be2dd1 | 151 | * @buf: data from user. |
1da177e4 LT |
152 | * @count: number of bytes in @userbuf. |
153 | * | |
154 | * Allocate @buffer->page if it hasn't been already, then | |
155 | * copy the user-supplied buffer into it. | |
156 | */ | |
1b18dc2b GKH |
157 | static int fill_write_buffer(struct sysfs_buffer *buffer, |
158 | const char __user *buf, size_t count) | |
1da177e4 LT |
159 | { |
160 | int error; | |
161 | ||
162 | if (!buffer->page) | |
163 | buffer->page = (char *)get_zeroed_page(GFP_KERNEL); | |
164 | if (!buffer->page) | |
165 | return -ENOMEM; | |
166 | ||
167 | if (count >= PAGE_SIZE) | |
6e0dd741 | 168 | count = PAGE_SIZE - 1; |
1b18dc2b | 169 | error = copy_from_user(buffer->page, buf, count); |
1da177e4 | 170 | buffer->needs_read_fill = 1; |
035ed7a4 TM |
171 | /* if buf is assumed to contain a string, terminate it by \0, |
172 | so e.g. sscanf() can scan the string easily */ | |
173 | buffer->page[count] = 0; | |
1da177e4 LT |
174 | return error ? -EFAULT : count; |
175 | } | |
176 | ||
177 | ||
178 | /** | |
179 | * flush_write_buffer - push buffer to kobject. | |
3d41088f | 180 | * @dentry: dentry to the attribute |
1da177e4 | 181 | * @buffer: data buffer for file. |
3d41088f | 182 | * @count: number of bytes |
1da177e4 LT |
183 | * |
184 | * Get the correct pointers for the kobject and the attribute we're | |
ab9bf4be | 185 | * dealing with, then call the store() method for the attribute, |
1da177e4 LT |
186 | * passing the buffer that we acquired in fill_write_buffer(). |
187 | */ | |
ddfd6d07 GKH |
188 | static int flush_write_buffer(struct dentry *dentry, |
189 | struct sysfs_buffer *buffer, size_t count) | |
1da177e4 | 190 | { |
3e519038 | 191 | struct sysfs_dirent *attr_sd = dentry->d_fsdata; |
b1fc3d61 | 192 | struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; |
1b18dc2b | 193 | const struct sysfs_ops *ops = buffer->ops; |
0ab66088 TH |
194 | int rc; |
195 | ||
196 | /* need attr_sd for attr and ops, its parent for kobj */ | |
e72ceb8c | 197 | if (!sysfs_get_active(attr_sd)) |
0ab66088 TH |
198 | return -ENODEV; |
199 | ||
b1fc3d61 | 200 | rc = ops->store(kobj, attr_sd->s_attr.attr, buffer->page, count); |
0ab66088 | 201 | |
e72ceb8c | 202 | sysfs_put_active(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 | |
ab9bf4be | 220 | * on the first write. |
1da177e4 | 221 | * Hint: if you're writing a value, first read the file, modify only the |
ab9bf4be | 222 | * the value you're changing, then write entire buffer back. |
1da177e4 | 223 | */ |
ddfd6d07 GKH |
224 | static ssize_t sysfs_write_file(struct file *file, const char __user *buf, |
225 | size_t count, loff_t *ppos) | |
1da177e4 | 226 | { |
1b18dc2b | 227 | struct sysfs_buffer *buffer = file->private_data; |
1da177e4 LT |
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: | |
83db93f4 | 261 | spin_lock_irq(&sysfs_open_dirent_lock); |
85a4ffad TH |
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 | ||
83db93f4 | 274 | spin_unlock_irq(&sysfs_open_dirent_lock); |
85a4ffad TH |
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; | |
83db93f4 | 308 | unsigned long flags; |
85a4ffad | 309 | |
83db93f4 | 310 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
85a4ffad TH |
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 | ||
83db93f4 | 318 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
85a4ffad TH |
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 | 327 | struct sysfs_buffer *buffer; |
52cf25d0 | 328 | const struct sysfs_ops *ops; |
000f2a4d | 329 | int error = -EACCES; |
1da177e4 | 330 | |
0ab66088 | 331 | /* need attr_sd for attr and ops, its parent for kobj */ |
e72ceb8c | 332 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 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 | 338 | else { |
07ac62a6 GKH |
339 | WARN(1, KERN_ERR |
340 | "missing sysfs attribute operations for kobject: %s\n", | |
341 | kobject_name(kobj)); | |
7b595756 | 342 | goto err_out; |
000f2a4d | 343 | } |
1da177e4 LT |
344 | |
345 | /* File needs write support. | |
ab9bf4be | 346 | * The inode's perms must say it's ok, |
1da177e4 LT |
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 */ |
e72ceb8c | 382 | sysfs_put_active(attr_sd); |
0ab66088 TH |
383 | return 0; |
384 | ||
85a4ffad TH |
385 | err_free: |
386 | kfree(buffer); | |
7b595756 | 387 | err_out: |
e72ceb8c | 388 | sysfs_put_active(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 | |
2424b5dd | 413 | * need to close and re-open the file, or seek to 0 and read again. |
4508a7a7 N |
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 | { | |
1b18dc2b | 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 */ | |
e72ceb8c | 426 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 427 | goto trigger; |
4508a7a7 | 428 | |
a4e8b912 | 429 | poll_wait(filp, &od->poll, wait); |
4508a7a7 | 430 | |
e72ceb8c | 431 | sysfs_put_active(attr_sd); |
0ab66088 | 432 | |
a4e8b912 | 433 | if (buffer->event != atomic_read(&od->event)) |
0ab66088 | 434 | goto trigger; |
4508a7a7 | 435 | |
1af3557a | 436 | return DEFAULT_POLLMASK; |
0ab66088 TH |
437 | |
438 | trigger: | |
439 | buffer->needs_read_fill = 1; | |
1af3557a | 440 | return DEFAULT_POLLMASK|POLLERR|POLLPRI; |
4508a7a7 N |
441 | } |
442 | ||
f1282c84 NB |
443 | void sysfs_notify_dirent(struct sysfs_dirent *sd) |
444 | { | |
445 | struct sysfs_open_dirent *od; | |
83db93f4 | 446 | unsigned long flags; |
f1282c84 | 447 | |
83db93f4 | 448 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
f1282c84 | 449 | |
fc60bb83 ND |
450 | if (!WARN_ON(sysfs_type(sd) != SYSFS_KOBJ_ATTR)) { |
451 | od = sd->s_attr.open; | |
452 | if (od) { | |
453 | atomic_inc(&od->event); | |
454 | wake_up_interruptible(&od->poll); | |
455 | } | |
f1282c84 NB |
456 | } |
457 | ||
83db93f4 | 458 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
f1282c84 NB |
459 | } |
460 | EXPORT_SYMBOL_GPL(sysfs_notify_dirent); | |
461 | ||
8c0e3998 | 462 | void sysfs_notify(struct kobject *k, const char *dir, const char *attr) |
4508a7a7 | 463 | { |
51225039 | 464 | struct sysfs_dirent *sd = k->sd; |
4508a7a7 | 465 | |
51225039 TH |
466 | mutex_lock(&sysfs_mutex); |
467 | ||
468 | if (sd && dir) | |
3ff195b0 | 469 | sd = sysfs_find_dirent(sd, NULL, dir); |
51225039 | 470 | if (sd && attr) |
3ff195b0 | 471 | sd = sysfs_find_dirent(sd, NULL, attr); |
f1282c84 NB |
472 | if (sd) |
473 | sysfs_notify_dirent(sd); | |
51225039 TH |
474 | |
475 | mutex_unlock(&sysfs_mutex); | |
4508a7a7 N |
476 | } |
477 | EXPORT_SYMBOL_GPL(sysfs_notify); | |
478 | ||
4b6f5d20 | 479 | const struct file_operations sysfs_file_operations = { |
1da177e4 LT |
480 | .read = sysfs_read_file, |
481 | .write = sysfs_write_file, | |
482 | .llseek = generic_file_llseek, | |
483 | .open = sysfs_open_file, | |
484 | .release = sysfs_release, | |
4508a7a7 | 485 | .poll = sysfs_poll, |
1da177e4 LT |
486 | }; |
487 | ||
1f20dfda JT |
488 | static int sysfs_attr_ns(struct kobject *kobj, const struct attribute *attr, |
489 | const void **pns) | |
487505c2 EB |
490 | { |
491 | struct sysfs_dirent *dir_sd = kobj->sd; | |
492 | const struct sysfs_ops *ops; | |
493 | const void *ns = NULL; | |
494 | int err; | |
495 | ||
ce597919 EB |
496 | if (!dir_sd) { |
497 | WARN(1, KERN_ERR "sysfs: kobject %s without dirent\n", | |
498 | kobject_name(kobj)); | |
499 | return -ENOENT; | |
500 | } | |
501 | ||
487505c2 EB |
502 | err = 0; |
503 | if (!sysfs_ns_type(dir_sd)) | |
504 | goto out; | |
505 | ||
506 | err = -EINVAL; | |
507 | if (!kobj->ktype) | |
508 | goto out; | |
509 | ops = kobj->ktype->sysfs_ops; | |
510 | if (!ops) | |
511 | goto out; | |
512 | if (!ops->namespace) | |
513 | goto out; | |
514 | ||
515 | err = 0; | |
516 | ns = ops->namespace(kobj, attr); | |
517 | out: | |
518 | if (err) { | |
07ac62a6 GKH |
519 | WARN(1, KERN_ERR |
520 | "missing sysfs namespace attribute operation for kobject: %s\n", | |
521 | kobject_name(kobj)); | |
487505c2 EB |
522 | } |
523 | *pns = ns; | |
524 | return err; | |
525 | } | |
526 | ||
0f423895 | 527 | int sysfs_add_file_mode(struct sysfs_dirent *dir_sd, |
faef2b6c | 528 | const struct attribute *attr, int type, umode_t amode) |
1da177e4 | 529 | { |
0f423895 | 530 | umode_t mode = (amode & S_IALLUGO) | S_IFREG; |
fb6896da | 531 | struct sysfs_addrm_cxt acxt; |
a26cd722 | 532 | struct sysfs_dirent *sd; |
487505c2 | 533 | const void *ns; |
23dc2799 | 534 | int rc; |
1da177e4 | 535 | |
487505c2 EB |
536 | rc = sysfs_attr_ns(dir_sd->s_dir.kobj, attr, &ns); |
537 | if (rc) | |
538 | return rc; | |
539 | ||
3007e997 TH |
540 | sd = sysfs_new_dirent(attr->name, mode, type); |
541 | if (!sd) | |
542 | return -ENOMEM; | |
487505c2 EB |
543 | |
544 | sd->s_ns = ns; | |
b1fc3d61 | 545 | sd->s_attr.attr = (void *)attr; |
a2db6842 | 546 | sysfs_dirent_init_lockdep(sd); |
1da177e4 | 547 | |
fb6896da | 548 | sysfs_addrm_start(&acxt, dir_sd); |
23dc2799 TH |
549 | rc = sysfs_add_one(&acxt, sd); |
550 | sysfs_addrm_finish(&acxt); | |
a26cd722 | 551 | |
23dc2799 | 552 | if (rc) |
967e35dc | 553 | sysfs_put(sd); |
3007e997 | 554 | |
23dc2799 | 555 | return rc; |
1da177e4 LT |
556 | } |
557 | ||
558 | ||
0f423895 JB |
559 | int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr, |
560 | int type) | |
561 | { | |
562 | return sysfs_add_file_mode(dir_sd, attr, type, attr->mode); | |
563 | } | |
564 | ||
565 | ||
1da177e4 LT |
566 | /** |
567 | * sysfs_create_file - create an attribute file for an object. | |
ab9bf4be | 568 | * @kobj: object we're creating for. |
3932bf60 | 569 | * @attr: attribute descriptor. |
1da177e4 | 570 | */ |
1b18dc2b | 571 | int sysfs_create_file(struct kobject *kobj, const struct attribute *attr) |
1da177e4 | 572 | { |
608e266a | 573 | BUG_ON(!kobj || !kobj->sd || !attr); |
1da177e4 | 574 | |
608e266a | 575 | return sysfs_add_file(kobj->sd, attr, SYSFS_KOBJ_ATTR); |
1da177e4 LT |
576 | |
577 | } | |
1b866757 | 578 | EXPORT_SYMBOL_GPL(sysfs_create_file); |
1da177e4 | 579 | |
1c205ae1 AK |
580 | int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr) |
581 | { | |
582 | int err = 0; | |
583 | int i; | |
584 | ||
585 | for (i = 0; ptr[i] && !err; i++) | |
586 | err = sysfs_create_file(kobj, ptr[i]); | |
587 | if (err) | |
588 | while (--i >= 0) | |
589 | sysfs_remove_file(kobj, ptr[i]); | |
590 | return err; | |
591 | } | |
1b866757 | 592 | EXPORT_SYMBOL_GPL(sysfs_create_files); |
1da177e4 | 593 | |
dfa87c82 AS |
594 | /** |
595 | * sysfs_add_file_to_group - add an attribute file to a pre-existing group. | |
596 | * @kobj: object we're acting for. | |
597 | * @attr: attribute descriptor. | |
598 | * @group: group name. | |
599 | */ | |
600 | int sysfs_add_file_to_group(struct kobject *kobj, | |
601 | const struct attribute *attr, const char *group) | |
602 | { | |
608e266a | 603 | struct sysfs_dirent *dir_sd; |
dfa87c82 AS |
604 | int error; |
605 | ||
11f24fbd | 606 | if (group) |
3ff195b0 | 607 | dir_sd = sysfs_get_dirent(kobj->sd, NULL, group); |
11f24fbd JB |
608 | else |
609 | dir_sd = sysfs_get(kobj->sd); | |
610 | ||
608e266a TH |
611 | if (!dir_sd) |
612 | return -ENOENT; | |
613 | ||
614 | error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR); | |
615 | sysfs_put(dir_sd); | |
616 | ||
dfa87c82 AS |
617 | return error; |
618 | } | |
619 | EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); | |
620 | ||
31e5abe9 KS |
621 | /** |
622 | * sysfs_chmod_file - update the modified mode value on an object attribute. | |
623 | * @kobj: object we're acting for. | |
624 | * @attr: attribute descriptor. | |
625 | * @mode: file permissions. | |
626 | * | |
627 | */ | |
49c19400 | 628 | int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr, |
48176a97 | 629 | umode_t mode) |
31e5abe9 | 630 | { |
06fc0d66 | 631 | struct sysfs_dirent *sd; |
bc062b1b | 632 | struct iattr newattrs; |
487505c2 | 633 | const void *ns; |
51225039 TH |
634 | int rc; |
635 | ||
487505c2 EB |
636 | rc = sysfs_attr_ns(kobj, attr, &ns); |
637 | if (rc) | |
638 | return rc; | |
639 | ||
06fc0d66 | 640 | mutex_lock(&sysfs_mutex); |
51225039 | 641 | |
06fc0d66 | 642 | rc = -ENOENT; |
487505c2 | 643 | sd = sysfs_find_dirent(kobj->sd, ns, attr->name); |
06fc0d66 | 644 | if (!sd) |
51225039 | 645 | goto out; |
f88123ea | 646 | |
06fc0d66 | 647 | newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO); |
4c6974f5 | 648 | newattrs.ia_valid = ATTR_MODE; |
06fc0d66 | 649 | rc = sysfs_sd_setattr(sd, &newattrs); |
f88123ea | 650 | |
51225039 | 651 | out: |
06fc0d66 | 652 | mutex_unlock(&sysfs_mutex); |
51225039 | 653 | return rc; |
31e5abe9 KS |
654 | } |
655 | EXPORT_SYMBOL_GPL(sysfs_chmod_file); | |
656 | ||
1da177e4 LT |
657 | /** |
658 | * sysfs_remove_file - remove an object attribute. | |
659 | * @kobj: object we're acting for. | |
660 | * @attr: attribute descriptor. | |
661 | * | |
662 | * Hash the attribute name and kill the victim. | |
663 | */ | |
1b18dc2b | 664 | void sysfs_remove_file(struct kobject *kobj, const struct attribute *attr) |
1da177e4 | 665 | { |
487505c2 EB |
666 | const void *ns; |
667 | ||
668 | if (sysfs_attr_ns(kobj, attr, &ns)) | |
669 | return; | |
670 | ||
671 | sysfs_hash_and_remove(kobj->sd, ns, attr->name); | |
1da177e4 | 672 | } |
1b866757 | 673 | EXPORT_SYMBOL_GPL(sysfs_remove_file); |
1da177e4 | 674 | |
1b18dc2b | 675 | void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr) |
1c205ae1 AK |
676 | { |
677 | int i; | |
678 | for (i = 0; ptr[i]; i++) | |
679 | sysfs_remove_file(kobj, ptr[i]); | |
680 | } | |
1b866757 | 681 | EXPORT_SYMBOL_GPL(sysfs_remove_files); |
1da177e4 | 682 | |
dfa87c82 AS |
683 | /** |
684 | * sysfs_remove_file_from_group - remove an attribute file from a group. | |
685 | * @kobj: object we're acting for. | |
686 | * @attr: attribute descriptor. | |
687 | * @group: group name. | |
688 | */ | |
689 | void sysfs_remove_file_from_group(struct kobject *kobj, | |
690 | const struct attribute *attr, const char *group) | |
691 | { | |
608e266a | 692 | struct sysfs_dirent *dir_sd; |
dfa87c82 | 693 | |
11f24fbd | 694 | if (group) |
3ff195b0 | 695 | dir_sd = sysfs_get_dirent(kobj->sd, NULL, group); |
11f24fbd JB |
696 | else |
697 | dir_sd = sysfs_get(kobj->sd); | |
608e266a | 698 | if (dir_sd) { |
3ff195b0 | 699 | sysfs_hash_and_remove(dir_sd, NULL, attr->name); |
608e266a | 700 | sysfs_put(dir_sd); |
dfa87c82 AS |
701 | } |
702 | } | |
703 | EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); | |
704 | ||
d9a9cdfb | 705 | struct sysfs_schedule_callback_struct { |
66942064 AC |
706 | struct list_head workq_list; |
707 | struct kobject *kobj; | |
d9a9cdfb AS |
708 | void (*func)(void *); |
709 | void *data; | |
523ded71 | 710 | struct module *owner; |
d9a9cdfb AS |
711 | struct work_struct work; |
712 | }; | |
713 | ||
d110271e | 714 | static struct workqueue_struct *sysfs_workqueue; |
66942064 AC |
715 | static DEFINE_MUTEX(sysfs_workq_mutex); |
716 | static LIST_HEAD(sysfs_workq); | |
d9a9cdfb AS |
717 | static void sysfs_schedule_callback_work(struct work_struct *work) |
718 | { | |
719 | struct sysfs_schedule_callback_struct *ss = container_of(work, | |
720 | struct sysfs_schedule_callback_struct, work); | |
721 | ||
722 | (ss->func)(ss->data); | |
723 | kobject_put(ss->kobj); | |
523ded71 | 724 | module_put(ss->owner); |
66942064 AC |
725 | mutex_lock(&sysfs_workq_mutex); |
726 | list_del(&ss->workq_list); | |
727 | mutex_unlock(&sysfs_workq_mutex); | |
d9a9cdfb AS |
728 | kfree(ss); |
729 | } | |
730 | ||
731 | /** | |
732 | * sysfs_schedule_callback - helper to schedule a callback for a kobject | |
733 | * @kobj: object we're acting for. | |
734 | * @func: callback function to invoke later. | |
735 | * @data: argument to pass to @func. | |
523ded71 | 736 | * @owner: module owning the callback code |
d9a9cdfb AS |
737 | * |
738 | * sysfs attribute methods must not unregister themselves or their parent | |
739 | * kobject (which would amount to the same thing). Attempts to do so will | |
740 | * deadlock, since unregistration is mutually exclusive with driver | |
741 | * callbacks. | |
742 | * | |
743 | * Instead methods can call this routine, which will attempt to allocate | |
744 | * and schedule a workqueue request to call back @func with @data as its | |
745 | * argument in the workqueue's process context. @kobj will be pinned | |
746 | * until @func returns. | |
747 | * | |
748 | * Returns 0 if the request was submitted, -ENOMEM if storage could not | |
66942064 AC |
749 | * be allocated, -ENODEV if a reference to @owner isn't available, |
750 | * -EAGAIN if a callback has already been scheduled for @kobj. | |
d9a9cdfb AS |
751 | */ |
752 | int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), | |
523ded71 | 753 | void *data, struct module *owner) |
d9a9cdfb | 754 | { |
66942064 | 755 | struct sysfs_schedule_callback_struct *ss, *tmp; |
d9a9cdfb | 756 | |
523ded71 AS |
757 | if (!try_module_get(owner)) |
758 | return -ENODEV; | |
66942064 AC |
759 | |
760 | mutex_lock(&sysfs_workq_mutex); | |
761 | list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list) | |
762 | if (ss->kobj == kobj) { | |
d110271e | 763 | module_put(owner); |
66942064 AC |
764 | mutex_unlock(&sysfs_workq_mutex); |
765 | return -EAGAIN; | |
766 | } | |
767 | mutex_unlock(&sysfs_workq_mutex); | |
768 | ||
d110271e | 769 | if (sysfs_workqueue == NULL) { |
086a377e | 770 | sysfs_workqueue = create_singlethread_workqueue("sysfsd"); |
d110271e AC |
771 | if (sysfs_workqueue == NULL) { |
772 | module_put(owner); | |
773 | return -ENOMEM; | |
774 | } | |
775 | } | |
776 | ||
d9a9cdfb | 777 | ss = kmalloc(sizeof(*ss), GFP_KERNEL); |
523ded71 AS |
778 | if (!ss) { |
779 | module_put(owner); | |
d9a9cdfb | 780 | return -ENOMEM; |
523ded71 | 781 | } |
d9a9cdfb AS |
782 | kobject_get(kobj); |
783 | ss->kobj = kobj; | |
784 | ss->func = func; | |
785 | ss->data = data; | |
523ded71 | 786 | ss->owner = owner; |
d9a9cdfb | 787 | INIT_WORK(&ss->work, sysfs_schedule_callback_work); |
66942064 AC |
788 | INIT_LIST_HEAD(&ss->workq_list); |
789 | mutex_lock(&sysfs_workq_mutex); | |
790 | list_add_tail(&ss->workq_list, &sysfs_workq); | |
791 | mutex_unlock(&sysfs_workq_mutex); | |
d110271e | 792 | queue_work(sysfs_workqueue, &ss->work); |
d9a9cdfb AS |
793 | return 0; |
794 | } | |
795 | EXPORT_SYMBOL_GPL(sysfs_schedule_callback); |