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> |
13c589d5 | 24 | #include <linux/seq_file.h> |
1da177e4 LT |
25 | |
26 | #include "sysfs.h" | |
27 | ||
85a4ffad | 28 | /* |
58282d8d | 29 | * There's one sysfs_open_file for each open file and one sysfs_open_dirent |
c75ec764 | 30 | * for each sysfs_dirent with one or more open files. |
85a4ffad | 31 | * |
c75ec764 TH |
32 | * sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open is |
33 | * protected by sysfs_open_dirent_lock. | |
34 | * | |
13c589d5 TH |
35 | * filp->private_data points to seq_file whose ->private points to |
36 | * sysfs_open_file. sysfs_open_files are chained at | |
58282d8d | 37 | * sysfs_open_dirent->files, which is protected by sysfs_open_file_mutex. |
85a4ffad | 38 | */ |
d7b37889 | 39 | static DEFINE_SPINLOCK(sysfs_open_dirent_lock); |
c75ec764 | 40 | static DEFINE_MUTEX(sysfs_open_file_mutex); |
85a4ffad TH |
41 | |
42 | struct sysfs_open_dirent { | |
43 | atomic_t refcnt; | |
a4e8b912 TH |
44 | atomic_t event; |
45 | wait_queue_head_t poll; | |
58282d8d | 46 | struct list_head files; /* goes through sysfs_open_file.list */ |
85a4ffad TH |
47 | }; |
48 | ||
58282d8d | 49 | struct sysfs_open_file { |
bcafe4ee TH |
50 | struct sysfs_dirent *sd; |
51 | struct file *file; | |
52e8c209 | 52 | struct mutex mutex; |
73107cb3 | 53 | int event; |
85a4ffad | 54 | struct list_head list; |
73107cb3 | 55 | }; |
1da177e4 | 56 | |
f9b9a621 TH |
57 | static bool sysfs_is_bin(struct sysfs_dirent *sd) |
58 | { | |
59 | return sysfs_type(sd) == SYSFS_KOBJ_BIN_ATTR; | |
60 | } | |
61 | ||
13c589d5 TH |
62 | static struct sysfs_open_file *sysfs_of(struct file *file) |
63 | { | |
64 | return ((struct seq_file *)file->private_data)->private; | |
65 | } | |
66 | ||
375b611e TH |
67 | /* |
68 | * Determine ktype->sysfs_ops for the given sysfs_dirent. This function | |
69 | * must be called while holding an active reference. | |
70 | */ | |
71 | static const struct sysfs_ops *sysfs_file_ops(struct sysfs_dirent *sd) | |
72 | { | |
73 | struct kobject *kobj = sd->s_parent->s_dir.kobj; | |
74 | ||
75 | lockdep_assert_held(sd); | |
76 | return kobj->ktype ? kobj->ktype->sysfs_ops : NULL; | |
77 | } | |
78 | ||
13c589d5 TH |
79 | /* |
80 | * Reads on sysfs are handled through seq_file, which takes care of hairy | |
81 | * details like buffering and seeking. The following function pipes | |
82 | * sysfs_ops->show() result through seq_file. | |
1da177e4 | 83 | */ |
13c589d5 | 84 | static int sysfs_seq_show(struct seq_file *sf, void *v) |
1da177e4 | 85 | { |
13c589d5 TH |
86 | struct sysfs_open_file *of = sf->private; |
87 | struct kobject *kobj = of->sd->s_parent->s_dir.kobj; | |
375b611e | 88 | const struct sysfs_ops *ops; |
13c589d5 | 89 | char *buf; |
1da177e4 LT |
90 | ssize_t count; |
91 | ||
13c589d5 TH |
92 | /* acquire buffer and ensure that it's >= PAGE_SIZE */ |
93 | count = seq_get_buf(sf, &buf); | |
94 | if (count < PAGE_SIZE) { | |
95 | seq_commit(sf, -1); | |
96 | return 0; | |
97 | } | |
1da177e4 | 98 | |
13c589d5 TH |
99 | /* |
100 | * Need @of->sd for attr and ops, its parent for kobj. @of->mutex | |
101 | * nests outside active ref and is just to ensure that the ops | |
102 | * aren't called concurrently for the same open file. | |
103 | */ | |
104 | mutex_lock(&of->mutex); | |
105 | if (!sysfs_get_active(of->sd)) { | |
106 | mutex_unlock(&of->mutex); | |
0ab66088 | 107 | return -ENODEV; |
13c589d5 | 108 | } |
0ab66088 | 109 | |
13c589d5 | 110 | of->event = atomic_read(&of->sd->s_attr.open->event); |
375b611e | 111 | |
13c589d5 TH |
112 | /* |
113 | * Lookup @ops and invoke show(). Control may reach here via seq | |
114 | * file lseek even if @ops->show() isn't implemented. | |
115 | */ | |
116 | ops = sysfs_file_ops(of->sd); | |
117 | if (ops->show) | |
118 | count = ops->show(kobj, of->sd->s_attr.attr, buf); | |
119 | else | |
120 | count = 0; | |
0ab66088 | 121 | |
13c589d5 TH |
122 | sysfs_put_active(of->sd); |
123 | mutex_unlock(&of->mutex); | |
124 | ||
125 | if (count < 0) | |
126 | return count; | |
0ab66088 | 127 | |
8118a859 MX |
128 | /* |
129 | * The code works fine with PAGE_SIZE return but it's likely to | |
130 | * indicate truncated result or overflow in normal use cases. | |
131 | */ | |
815d2d50 AM |
132 | if (count >= (ssize_t)PAGE_SIZE) { |
133 | print_symbol("fill_read_buffer: %s returned bad count\n", | |
134 | (unsigned long)ops->show); | |
135 | /* Try to struggle along */ | |
136 | count = PAGE_SIZE - 1; | |
137 | } | |
13c589d5 TH |
138 | seq_commit(sf, count); |
139 | return 0; | |
1da177e4 LT |
140 | } |
141 | ||
1da177e4 | 142 | /** |
8ef445f0 TH |
143 | * flush_write_buffer - push buffer to kobject |
144 | * @of: open file | |
145 | * @buf: data buffer for file | |
f9b9a621 | 146 | * @off: file offset to write to |
8ef445f0 | 147 | * @count: number of bytes |
1da177e4 | 148 | * |
8ef445f0 TH |
149 | * Get the correct pointers for the kobject and the attribute we're dealing |
150 | * with, then call the store() method for it with @buf. | |
1da177e4 | 151 | */ |
f9b9a621 | 152 | static int flush_write_buffer(struct sysfs_open_file *of, char *buf, loff_t off, |
8ef445f0 | 153 | size_t count) |
1da177e4 | 154 | { |
bcafe4ee | 155 | struct kobject *kobj = of->sd->s_parent->s_dir.kobj; |
8ef445f0 | 156 | int rc = 0; |
0ab66088 | 157 | |
8ef445f0 TH |
158 | /* |
159 | * Need @of->sd for attr and ops, its parent for kobj. @of->mutex | |
160 | * nests outside active ref and is just to ensure that the ops | |
161 | * aren't called concurrently for the same open file. | |
162 | */ | |
163 | mutex_lock(&of->mutex); | |
164 | if (!sysfs_get_active(of->sd)) { | |
165 | mutex_unlock(&of->mutex); | |
0ab66088 | 166 | return -ENODEV; |
8ef445f0 | 167 | } |
0ab66088 | 168 | |
f9b9a621 TH |
169 | if (sysfs_is_bin(of->sd)) { |
170 | struct bin_attribute *battr = of->sd->s_bin_attr.bin_attr; | |
171 | ||
172 | rc = -EIO; | |
173 | if (battr->write) | |
174 | rc = battr->write(of->file, kobj, battr, buf, off, | |
175 | count); | |
176 | } else { | |
177 | const struct sysfs_ops *ops = sysfs_file_ops(of->sd); | |
178 | ||
179 | rc = ops->store(kobj, of->sd->s_attr.attr, buf, count); | |
180 | } | |
0ab66088 | 181 | |
bcafe4ee | 182 | sysfs_put_active(of->sd); |
8ef445f0 | 183 | mutex_unlock(&of->mutex); |
1da177e4 | 184 | |
0ab66088 | 185 | return rc; |
1da177e4 LT |
186 | } |
187 | ||
1da177e4 | 188 | /** |
8ef445f0 TH |
189 | * sysfs_write_file - write an attribute |
190 | * @file: file pointer | |
191 | * @user_buf: data to write | |
192 | * @count: number of bytes | |
193 | * @ppos: starting offset | |
194 | * | |
195 | * Copy data in from userland and pass it to the matching | |
196 | * sysfs_ops->store() by invoking flush_write_buffer(). | |
1da177e4 | 197 | * |
8ef445f0 TH |
198 | * There is no easy way for us to know if userspace is only doing a partial |
199 | * write, so we don't support them. We expect the entire buffer to come on | |
200 | * the first write. Hint: if you're writing a value, first read the file, | |
201 | * modify only the the value you're changing, then write entire buffer | |
202 | * back. | |
1da177e4 | 203 | */ |
8ef445f0 | 204 | static ssize_t sysfs_write_file(struct file *file, const char __user *user_buf, |
ddfd6d07 | 205 | size_t count, loff_t *ppos) |
1da177e4 | 206 | { |
13c589d5 | 207 | struct sysfs_open_file *of = sysfs_of(file); |
f9b9a621 | 208 | ssize_t len = min_t(size_t, count, PAGE_SIZE); |
8ef445f0 | 209 | char *buf; |
1da177e4 | 210 | |
f9b9a621 TH |
211 | if (sysfs_is_bin(of->sd)) { |
212 | loff_t size = file_inode(file)->i_size; | |
213 | ||
214 | if (size <= *ppos) | |
215 | return 0; | |
216 | len = min_t(ssize_t, len, size - *ppos); | |
217 | } | |
218 | ||
8ef445f0 TH |
219 | if (!len) |
220 | return 0; | |
221 | ||
222 | buf = kmalloc(len + 1, GFP_KERNEL); | |
223 | if (!buf) | |
224 | return -ENOMEM; | |
225 | ||
226 | if (copy_from_user(buf, user_buf, len)) { | |
227 | len = -EFAULT; | |
228 | goto out_free; | |
229 | } | |
230 | buf[len] = '\0'; /* guarantee string termination */ | |
231 | ||
f9b9a621 | 232 | len = flush_write_buffer(of, buf, *ppos, len); |
1da177e4 LT |
233 | if (len > 0) |
234 | *ppos += len; | |
8ef445f0 TH |
235 | out_free: |
236 | kfree(buf); | |
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 | |
58282d8d | 243 | * @of: sysfs_open_file for this instance of open |
85a4ffad TH |
244 | * |
245 | * If @sd->s_attr.open exists, increment its reference count; | |
58282d8d | 246 | * otherwise, create one. @of is chained to the files list. |
85a4ffad TH |
247 | * |
248 | * LOCKING: | |
249 | * Kernel thread context (may sleep). | |
250 | * | |
251 | * RETURNS: | |
252 | * 0 on success, -errno on failure. | |
253 | */ | |
254 | static int sysfs_get_open_dirent(struct sysfs_dirent *sd, | |
58282d8d | 255 | struct sysfs_open_file *of) |
85a4ffad TH |
256 | { |
257 | struct sysfs_open_dirent *od, *new_od = NULL; | |
258 | ||
259 | retry: | |
c75ec764 | 260 | mutex_lock(&sysfs_open_file_mutex); |
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); | |
58282d8d | 271 | list_add_tail(&of->list, &od->files); |
85a4ffad TH |
272 | } |
273 | ||
83db93f4 | 274 | spin_unlock_irq(&sysfs_open_dirent_lock); |
c75ec764 | 275 | mutex_unlock(&sysfs_open_file_mutex); |
85a4ffad TH |
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); | |
58282d8d | 290 | INIT_LIST_HEAD(&new_od->files); |
85a4ffad TH |
291 | goto retry; |
292 | } | |
293 | ||
294 | /** | |
295 | * sysfs_put_open_dirent - put sysfs_open_dirent | |
296 | * @sd: target sysfs_dirent | |
58282d8d | 297 | * @of: associated sysfs_open_file |
85a4ffad | 298 | * |
58282d8d TH |
299 | * Put @sd->s_attr.open and unlink @of from the files list. If |
300 | * reference count reaches zero, disassociate and free it. | |
85a4ffad TH |
301 | * |
302 | * LOCKING: | |
303 | * None. | |
304 | */ | |
305 | static void sysfs_put_open_dirent(struct sysfs_dirent *sd, | |
58282d8d | 306 | struct sysfs_open_file *of) |
85a4ffad TH |
307 | { |
308 | struct sysfs_open_dirent *od = sd->s_attr.open; | |
83db93f4 | 309 | unsigned long flags; |
85a4ffad | 310 | |
c75ec764 | 311 | mutex_lock(&sysfs_open_file_mutex); |
83db93f4 | 312 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
85a4ffad | 313 | |
58282d8d | 314 | list_del(&of->list); |
85a4ffad TH |
315 | if (atomic_dec_and_test(&od->refcnt)) |
316 | sd->s_attr.open = NULL; | |
317 | else | |
318 | od = NULL; | |
319 | ||
83db93f4 | 320 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
c75ec764 | 321 | mutex_unlock(&sysfs_open_file_mutex); |
85a4ffad TH |
322 | |
323 | kfree(od); | |
324 | } | |
325 | ||
94bebf4d | 326 | static int sysfs_open_file(struct inode *inode, struct file *file) |
1da177e4 | 327 | { |
3e519038 | 328 | struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; |
b1fc3d61 | 329 | struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; |
58282d8d | 330 | struct sysfs_open_file *of; |
52cf25d0 | 331 | const struct sysfs_ops *ops; |
000f2a4d | 332 | int error = -EACCES; |
1da177e4 | 333 | |
0ab66088 | 334 | /* need attr_sd for attr and ops, its parent for kobj */ |
e72ceb8c | 335 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 336 | return -ENODEV; |
1da177e4 | 337 | |
000f2a4d | 338 | /* every kobject with an attribute needs a ktype assigned */ |
375b611e TH |
339 | ops = sysfs_file_ops(attr_sd); |
340 | if (WARN(!ops, KERN_ERR | |
341 | "missing sysfs attribute operations for kobject: %s\n", | |
342 | kobject_name(kobj))) | |
7b595756 | 343 | goto err_out; |
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 | ||
13c589d5 | 363 | /* allocate a sysfs_open_file for the file */ |
0ab66088 | 364 | error = -ENOMEM; |
58282d8d TH |
365 | of = kzalloc(sizeof(struct sysfs_open_file), GFP_KERNEL); |
366 | if (!of) | |
7b595756 | 367 | goto err_out; |
1da177e4 | 368 | |
58282d8d | 369 | mutex_init(&of->mutex); |
bcafe4ee TH |
370 | of->sd = attr_sd; |
371 | of->file = file; | |
13c589d5 TH |
372 | |
373 | /* | |
374 | * Always instantiate seq_file even if read access is not | |
375 | * implemented or requested. This unifies private data access and | |
376 | * most files are readable anyway. | |
377 | */ | |
378 | error = single_open(file, sysfs_seq_show, of); | |
379 | if (error) | |
380 | goto err_free; | |
381 | ||
382 | /* seq_file clears PWRITE unconditionally, restore it if WRITE */ | |
383 | if (file->f_mode & FMODE_WRITE) | |
384 | file->f_mode |= FMODE_PWRITE; | |
0ab66088 | 385 | |
85a4ffad | 386 | /* make sure we have open dirent struct */ |
58282d8d | 387 | error = sysfs_get_open_dirent(attr_sd, of); |
85a4ffad | 388 | if (error) |
13c589d5 | 389 | goto err_close; |
85a4ffad | 390 | |
b05f0548 | 391 | /* open succeeded, put active references */ |
e72ceb8c | 392 | sysfs_put_active(attr_sd); |
0ab66088 TH |
393 | return 0; |
394 | ||
13c589d5 TH |
395 | err_close: |
396 | single_release(inode, file); | |
397 | err_free: | |
58282d8d | 398 | kfree(of); |
13c589d5 | 399 | err_out: |
e72ceb8c | 400 | sysfs_put_active(attr_sd); |
1da177e4 LT |
401 | return error; |
402 | } | |
403 | ||
85a4ffad | 404 | static int sysfs_release(struct inode *inode, struct file *filp) |
1da177e4 | 405 | { |
85a4ffad | 406 | struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata; |
13c589d5 | 407 | struct sysfs_open_file *of = sysfs_of(filp); |
1da177e4 | 408 | |
58282d8d | 409 | sysfs_put_open_dirent(sd, of); |
13c589d5 | 410 | single_release(inode, filp); |
58282d8d | 411 | kfree(of); |
50ab1a72 | 412 | |
1da177e4 LT |
413 | return 0; |
414 | } | |
415 | ||
4508a7a7 N |
416 | /* Sysfs attribute files are pollable. The idea is that you read |
417 | * the content and then you use 'poll' or 'select' to wait for | |
418 | * the content to change. When the content changes (assuming the | |
419 | * manager for the kobject supports notification), poll will | |
420 | * return POLLERR|POLLPRI, and select will return the fd whether | |
421 | * it is waiting for read, write, or exceptions. | |
422 | * Once poll/select indicates that the value has changed, you | |
2424b5dd | 423 | * need to close and re-open the file, or seek to 0 and read again. |
4508a7a7 N |
424 | * Reminder: this only works for attributes which actively support |
425 | * it, and it is not possible to test an attribute from userspace | |
a93720ee | 426 | * to see if it supports poll (Neither 'poll' nor 'select' return |
4508a7a7 N |
427 | * an appropriate error code). When in doubt, set a suitable timeout value. |
428 | */ | |
429 | static unsigned int sysfs_poll(struct file *filp, poll_table *wait) | |
430 | { | |
13c589d5 | 431 | struct sysfs_open_file *of = sysfs_of(filp); |
0ab66088 | 432 | struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata; |
a4e8b912 | 433 | struct sysfs_open_dirent *od = attr_sd->s_attr.open; |
0ab66088 TH |
434 | |
435 | /* need parent for the kobj, grab both */ | |
e72ceb8c | 436 | if (!sysfs_get_active(attr_sd)) |
0ab66088 | 437 | goto trigger; |
4508a7a7 | 438 | |
a4e8b912 | 439 | poll_wait(filp, &od->poll, wait); |
4508a7a7 | 440 | |
e72ceb8c | 441 | sysfs_put_active(attr_sd); |
0ab66088 | 442 | |
58282d8d | 443 | if (of->event != atomic_read(&od->event)) |
0ab66088 | 444 | goto trigger; |
4508a7a7 | 445 | |
1af3557a | 446 | return DEFAULT_POLLMASK; |
0ab66088 TH |
447 | |
448 | trigger: | |
1af3557a | 449 | return DEFAULT_POLLMASK|POLLERR|POLLPRI; |
4508a7a7 N |
450 | } |
451 | ||
f1282c84 NB |
452 | void sysfs_notify_dirent(struct sysfs_dirent *sd) |
453 | { | |
454 | struct sysfs_open_dirent *od; | |
83db93f4 | 455 | unsigned long flags; |
f1282c84 | 456 | |
83db93f4 | 457 | spin_lock_irqsave(&sysfs_open_dirent_lock, flags); |
f1282c84 | 458 | |
fc60bb83 ND |
459 | if (!WARN_ON(sysfs_type(sd) != SYSFS_KOBJ_ATTR)) { |
460 | od = sd->s_attr.open; | |
461 | if (od) { | |
462 | atomic_inc(&od->event); | |
463 | wake_up_interruptible(&od->poll); | |
464 | } | |
f1282c84 NB |
465 | } |
466 | ||
83db93f4 | 467 | spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); |
f1282c84 NB |
468 | } |
469 | EXPORT_SYMBOL_GPL(sysfs_notify_dirent); | |
470 | ||
8c0e3998 | 471 | void sysfs_notify(struct kobject *k, const char *dir, const char *attr) |
4508a7a7 | 472 | { |
51225039 | 473 | struct sysfs_dirent *sd = k->sd; |
4508a7a7 | 474 | |
51225039 TH |
475 | mutex_lock(&sysfs_mutex); |
476 | ||
477 | if (sd && dir) | |
cfec0bc8 | 478 | sd = sysfs_find_dirent(sd, dir, NULL); |
51225039 | 479 | if (sd && attr) |
cfec0bc8 | 480 | sd = sysfs_find_dirent(sd, attr, NULL); |
f1282c84 NB |
481 | if (sd) |
482 | sysfs_notify_dirent(sd); | |
51225039 TH |
483 | |
484 | mutex_unlock(&sysfs_mutex); | |
4508a7a7 N |
485 | } |
486 | EXPORT_SYMBOL_GPL(sysfs_notify); | |
487 | ||
4b6f5d20 | 488 | const struct file_operations sysfs_file_operations = { |
13c589d5 | 489 | .read = seq_read, |
1da177e4 | 490 | .write = sysfs_write_file, |
13c589d5 | 491 | .llseek = seq_lseek, |
1da177e4 LT |
492 | .open = sysfs_open_file, |
493 | .release = sysfs_release, | |
4508a7a7 | 494 | .poll = sysfs_poll, |
1da177e4 LT |
495 | }; |
496 | ||
f9b9a621 TH |
497 | const struct file_operations sysfs_bin_operations = { |
498 | .write = sysfs_write_file, | |
499 | .llseek = generic_file_llseek, | |
500 | }; | |
501 | ||
58292cbe TH |
502 | int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd, |
503 | const struct attribute *attr, int type, | |
504 | umode_t amode, const void *ns) | |
1da177e4 | 505 | { |
0f423895 | 506 | umode_t mode = (amode & S_IALLUGO) | S_IFREG; |
fb6896da | 507 | struct sysfs_addrm_cxt acxt; |
a26cd722 | 508 | struct sysfs_dirent *sd; |
23dc2799 | 509 | int rc; |
1da177e4 | 510 | |
3007e997 TH |
511 | sd = sysfs_new_dirent(attr->name, mode, type); |
512 | if (!sd) | |
513 | return -ENOMEM; | |
487505c2 EB |
514 | |
515 | sd->s_ns = ns; | |
b1fc3d61 | 516 | sd->s_attr.attr = (void *)attr; |
a2db6842 | 517 | sysfs_dirent_init_lockdep(sd); |
1da177e4 | 518 | |
d69ac5a0 TH |
519 | sysfs_addrm_start(&acxt); |
520 | rc = sysfs_add_one(&acxt, sd, dir_sd); | |
23dc2799 | 521 | sysfs_addrm_finish(&acxt); |
a26cd722 | 522 | |
23dc2799 | 523 | if (rc) |
967e35dc | 524 | sysfs_put(sd); |
3007e997 | 525 | |
23dc2799 | 526 | return rc; |
1da177e4 LT |
527 | } |
528 | ||
529 | ||
0f423895 JB |
530 | int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr, |
531 | int type) | |
532 | { | |
58292cbe | 533 | return sysfs_add_file_mode_ns(dir_sd, attr, type, attr->mode, NULL); |
0f423895 JB |
534 | } |
535 | ||
1da177e4 | 536 | /** |
58292cbe TH |
537 | * sysfs_create_file_ns - create an attribute file for an object with custom ns |
538 | * @kobj: object we're creating for | |
539 | * @attr: attribute descriptor | |
540 | * @ns: namespace the new file should belong to | |
1da177e4 | 541 | */ |
58292cbe TH |
542 | int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr, |
543 | const void *ns) | |
1da177e4 | 544 | { |
608e266a | 545 | BUG_ON(!kobj || !kobj->sd || !attr); |
1da177e4 | 546 | |
58292cbe TH |
547 | return sysfs_add_file_mode_ns(kobj->sd, attr, SYSFS_KOBJ_ATTR, |
548 | attr->mode, ns); | |
1da177e4 LT |
549 | |
550 | } | |
58292cbe | 551 | EXPORT_SYMBOL_GPL(sysfs_create_file_ns); |
1da177e4 | 552 | |
1c205ae1 AK |
553 | int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr) |
554 | { | |
555 | int err = 0; | |
556 | int i; | |
557 | ||
558 | for (i = 0; ptr[i] && !err; i++) | |
559 | err = sysfs_create_file(kobj, ptr[i]); | |
560 | if (err) | |
561 | while (--i >= 0) | |
562 | sysfs_remove_file(kobj, ptr[i]); | |
563 | return err; | |
564 | } | |
1b866757 | 565 | EXPORT_SYMBOL_GPL(sysfs_create_files); |
1da177e4 | 566 | |
dfa87c82 AS |
567 | /** |
568 | * sysfs_add_file_to_group - add an attribute file to a pre-existing group. | |
569 | * @kobj: object we're acting for. | |
570 | * @attr: attribute descriptor. | |
571 | * @group: group name. | |
572 | */ | |
573 | int sysfs_add_file_to_group(struct kobject *kobj, | |
574 | const struct attribute *attr, const char *group) | |
575 | { | |
608e266a | 576 | struct sysfs_dirent *dir_sd; |
dfa87c82 AS |
577 | int error; |
578 | ||
11f24fbd | 579 | if (group) |
388975cc | 580 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
11f24fbd JB |
581 | else |
582 | dir_sd = sysfs_get(kobj->sd); | |
583 | ||
608e266a TH |
584 | if (!dir_sd) |
585 | return -ENOENT; | |
586 | ||
587 | error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR); | |
588 | sysfs_put(dir_sd); | |
589 | ||
dfa87c82 AS |
590 | return error; |
591 | } | |
592 | EXPORT_SYMBOL_GPL(sysfs_add_file_to_group); | |
593 | ||
31e5abe9 KS |
594 | /** |
595 | * sysfs_chmod_file - update the modified mode value on an object attribute. | |
596 | * @kobj: object we're acting for. | |
597 | * @attr: attribute descriptor. | |
598 | * @mode: file permissions. | |
599 | * | |
600 | */ | |
49c19400 | 601 | int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr, |
48176a97 | 602 | umode_t mode) |
31e5abe9 | 603 | { |
06fc0d66 | 604 | struct sysfs_dirent *sd; |
bc062b1b | 605 | struct iattr newattrs; |
51225039 TH |
606 | int rc; |
607 | ||
06fc0d66 | 608 | mutex_lock(&sysfs_mutex); |
51225039 | 609 | |
06fc0d66 | 610 | rc = -ENOENT; |
cfec0bc8 | 611 | sd = sysfs_find_dirent(kobj->sd, attr->name, NULL); |
06fc0d66 | 612 | if (!sd) |
51225039 | 613 | goto out; |
f88123ea | 614 | |
06fc0d66 | 615 | newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO); |
4c6974f5 | 616 | newattrs.ia_valid = ATTR_MODE; |
06fc0d66 | 617 | rc = sysfs_sd_setattr(sd, &newattrs); |
f88123ea | 618 | |
51225039 | 619 | out: |
06fc0d66 | 620 | mutex_unlock(&sysfs_mutex); |
51225039 | 621 | return rc; |
31e5abe9 KS |
622 | } |
623 | EXPORT_SYMBOL_GPL(sysfs_chmod_file); | |
624 | ||
1da177e4 | 625 | /** |
58292cbe TH |
626 | * sysfs_remove_file_ns - remove an object attribute with a custom ns tag |
627 | * @kobj: object we're acting for | |
628 | * @attr: attribute descriptor | |
629 | * @ns: namespace tag of the file to remove | |
1da177e4 | 630 | * |
58292cbe | 631 | * Hash the attribute name and namespace tag and kill the victim. |
1da177e4 | 632 | */ |
58292cbe TH |
633 | void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr, |
634 | const void *ns) | |
1da177e4 | 635 | { |
58292cbe | 636 | struct sysfs_dirent *dir_sd = kobj->sd; |
487505c2 | 637 | |
cfec0bc8 | 638 | sysfs_hash_and_remove(dir_sd, attr->name, ns); |
1da177e4 | 639 | } |
58292cbe | 640 | EXPORT_SYMBOL_GPL(sysfs_remove_file_ns); |
1da177e4 | 641 | |
1b18dc2b | 642 | void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr) |
1c205ae1 AK |
643 | { |
644 | int i; | |
645 | for (i = 0; ptr[i]; i++) | |
646 | sysfs_remove_file(kobj, ptr[i]); | |
647 | } | |
1b866757 | 648 | EXPORT_SYMBOL_GPL(sysfs_remove_files); |
1da177e4 | 649 | |
dfa87c82 AS |
650 | /** |
651 | * sysfs_remove_file_from_group - remove an attribute file from a group. | |
652 | * @kobj: object we're acting for. | |
653 | * @attr: attribute descriptor. | |
654 | * @group: group name. | |
655 | */ | |
656 | void sysfs_remove_file_from_group(struct kobject *kobj, | |
657 | const struct attribute *attr, const char *group) | |
658 | { | |
608e266a | 659 | struct sysfs_dirent *dir_sd; |
dfa87c82 | 660 | |
11f24fbd | 661 | if (group) |
388975cc | 662 | dir_sd = sysfs_get_dirent(kobj->sd, group); |
11f24fbd JB |
663 | else |
664 | dir_sd = sysfs_get(kobj->sd); | |
608e266a | 665 | if (dir_sd) { |
cfec0bc8 | 666 | sysfs_hash_and_remove(dir_sd, attr->name, NULL); |
608e266a | 667 | sysfs_put(dir_sd); |
dfa87c82 AS |
668 | } |
669 | } | |
670 | EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); | |
671 | ||
d9a9cdfb | 672 | struct sysfs_schedule_callback_struct { |
66942064 AC |
673 | struct list_head workq_list; |
674 | struct kobject *kobj; | |
d9a9cdfb AS |
675 | void (*func)(void *); |
676 | void *data; | |
523ded71 | 677 | struct module *owner; |
d9a9cdfb AS |
678 | struct work_struct work; |
679 | }; | |
680 | ||
d110271e | 681 | static struct workqueue_struct *sysfs_workqueue; |
66942064 AC |
682 | static DEFINE_MUTEX(sysfs_workq_mutex); |
683 | static LIST_HEAD(sysfs_workq); | |
d9a9cdfb AS |
684 | static void sysfs_schedule_callback_work(struct work_struct *work) |
685 | { | |
686 | struct sysfs_schedule_callback_struct *ss = container_of(work, | |
687 | struct sysfs_schedule_callback_struct, work); | |
688 | ||
689 | (ss->func)(ss->data); | |
690 | kobject_put(ss->kobj); | |
523ded71 | 691 | module_put(ss->owner); |
66942064 AC |
692 | mutex_lock(&sysfs_workq_mutex); |
693 | list_del(&ss->workq_list); | |
694 | mutex_unlock(&sysfs_workq_mutex); | |
d9a9cdfb AS |
695 | kfree(ss); |
696 | } | |
697 | ||
698 | /** | |
699 | * sysfs_schedule_callback - helper to schedule a callback for a kobject | |
700 | * @kobj: object we're acting for. | |
701 | * @func: callback function to invoke later. | |
702 | * @data: argument to pass to @func. | |
523ded71 | 703 | * @owner: module owning the callback code |
d9a9cdfb AS |
704 | * |
705 | * sysfs attribute methods must not unregister themselves or their parent | |
706 | * kobject (which would amount to the same thing). Attempts to do so will | |
707 | * deadlock, since unregistration is mutually exclusive with driver | |
708 | * callbacks. | |
709 | * | |
710 | * Instead methods can call this routine, which will attempt to allocate | |
711 | * and schedule a workqueue request to call back @func with @data as its | |
712 | * argument in the workqueue's process context. @kobj will be pinned | |
713 | * until @func returns. | |
714 | * | |
715 | * Returns 0 if the request was submitted, -ENOMEM if storage could not | |
66942064 AC |
716 | * be allocated, -ENODEV if a reference to @owner isn't available, |
717 | * -EAGAIN if a callback has already been scheduled for @kobj. | |
d9a9cdfb AS |
718 | */ |
719 | int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), | |
523ded71 | 720 | void *data, struct module *owner) |
d9a9cdfb | 721 | { |
66942064 | 722 | struct sysfs_schedule_callback_struct *ss, *tmp; |
d9a9cdfb | 723 | |
523ded71 AS |
724 | if (!try_module_get(owner)) |
725 | return -ENODEV; | |
66942064 AC |
726 | |
727 | mutex_lock(&sysfs_workq_mutex); | |
728 | list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list) | |
729 | if (ss->kobj == kobj) { | |
d110271e | 730 | module_put(owner); |
66942064 AC |
731 | mutex_unlock(&sysfs_workq_mutex); |
732 | return -EAGAIN; | |
733 | } | |
734 | mutex_unlock(&sysfs_workq_mutex); | |
735 | ||
d110271e | 736 | if (sysfs_workqueue == NULL) { |
086a377e | 737 | sysfs_workqueue = create_singlethread_workqueue("sysfsd"); |
d110271e AC |
738 | if (sysfs_workqueue == NULL) { |
739 | module_put(owner); | |
740 | return -ENOMEM; | |
741 | } | |
742 | } | |
743 | ||
d9a9cdfb | 744 | ss = kmalloc(sizeof(*ss), GFP_KERNEL); |
523ded71 AS |
745 | if (!ss) { |
746 | module_put(owner); | |
d9a9cdfb | 747 | return -ENOMEM; |
523ded71 | 748 | } |
d9a9cdfb AS |
749 | kobject_get(kobj); |
750 | ss->kobj = kobj; | |
751 | ss->func = func; | |
752 | ss->data = data; | |
523ded71 | 753 | ss->owner = owner; |
d9a9cdfb | 754 | INIT_WORK(&ss->work, sysfs_schedule_callback_work); |
66942064 AC |
755 | INIT_LIST_HEAD(&ss->workq_list); |
756 | mutex_lock(&sysfs_workq_mutex); | |
757 | list_add_tail(&ss->workq_list, &sysfs_workq); | |
758 | mutex_unlock(&sysfs_workq_mutex); | |
d110271e | 759 | queue_work(sysfs_workqueue, &ss->work); |
d9a9cdfb AS |
760 | return 0; |
761 | } | |
762 | EXPORT_SYMBOL_GPL(sysfs_schedule_callback); |