1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Routines for driver control interface
4 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5 */
6
7 #include <linux/threads.h>
8 #include <linux/interrupt.h>
9 #include <linux/module.h>
10 #include <linux/moduleparam.h>
11 #include <linux/slab.h>
12 #include <linux/vmalloc.h>
13 #include <linux/time.h>
14 #include <linux/mm.h>
15 #include <linux/math64.h>
16 #include <linux/sched/signal.h>
17 #include <sound/core.h>
18 #include <sound/minors.h>
19 #include <sound/info.h>
20 #include <sound/control.h>
21
22 // Max allocation size for user controls.
23 static int max_user_ctl_alloc_size = 8 * 1024 * 1024;
24 module_param_named(max_user_ctl_alloc_size, max_user_ctl_alloc_size, int, 0444);
25 MODULE_PARM_DESC(max_user_ctl_alloc_size, "Max allocation size for user controls");
26
27 #define MAX_CONTROL_COUNT 1028
28
29 struct snd_kctl_ioctl {
30 struct list_head list; /* list of all ioctls */
31 snd_kctl_ioctl_func_t fioctl;
32 };
33
34 static DECLARE_RWSEM(snd_ioctl_rwsem);
35 static DECLARE_RWSEM(snd_ctl_layer_rwsem);
36 static LIST_HEAD(snd_control_ioctls);
37 #ifdef CONFIG_COMPAT
38 static LIST_HEAD(snd_control_compat_ioctls);
39 #endif
40 static struct snd_ctl_layer_ops *snd_ctl_layer;
41
42 static int snd_ctl_remove_locked(struct snd_card *card,
43 struct snd_kcontrol *kcontrol);
44
45 static int snd_ctl_open(struct inode *inode, struct file *file)
46 {
47 struct snd_card *card;
48 struct snd_ctl_file *ctl;
49 int i, err;
50
51 err = stream_open(inode, file);
52 if (err < 0)
53 return err;
54
55 card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
56 if (!card) {
57 err = -ENODEV;
58 goto __error1;
59 }
60 err = snd_card_file_add(card, file);
61 if (err < 0) {
62 err = -ENODEV;
63 goto __error1;
64 }
65 if (!try_module_get(card->module)) {
66 err = -EFAULT;
67 goto __error2;
68 }
69 ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
70 if (ctl == NULL) {
71 err = -ENOMEM;
72 goto __error;
73 }
74 INIT_LIST_HEAD(&ctl->events);
75 init_waitqueue_head(&ctl->change_sleep);
76 spin_lock_init(&ctl->read_lock);
77 ctl->card = card;
78 for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
79 ctl->preferred_subdevice[i] = -1;
80 ctl->pid = get_pid(task_pid(current));
81 file->private_data = ctl;
82 scoped_guard(write_lock_irqsave, &card->ctl_files_rwlock)
83 list_add_tail(&ctl->list, &card->ctl_files);
84 snd_card_unref(card);
85 return 0;
86
87 __error:
88 module_put(card->module);
89 __error2:
90 snd_card_file_remove(card, file);
91 __error1:
92 if (card)
93 snd_card_unref(card);
94 return err;
95 }
96
97 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
98 {
99 struct snd_kctl_event *cread;
100
101 guard(spinlock_irqsave)(&ctl->read_lock);
102 while (!list_empty(&ctl->events)) {
103 cread = snd_kctl_event(ctl->events.next);
104 list_del(&cread->list);
105 kfree(cread);
106 }
107 }
108
109 static int snd_ctl_release(struct inode *inode, struct file *file)
110 {
111 struct snd_card *card;
112 struct snd_ctl_file *ctl;
113 struct snd_kcontrol *control;
114 unsigned int idx;
115
116 ctl = file->private_data;
117 file->private_data = NULL;
118 card = ctl->card;
119
120 scoped_guard(write_lock_irqsave, &card->ctl_files_rwlock)
121 list_del(&ctl->list);
122
123 scoped_guard(rwsem_write, &card->controls_rwsem) {
124 list_for_each_entry(control, &card->controls, list)
125 for (idx = 0; idx < control->count; idx++)
126 if (control->vd[idx].owner == ctl)
127 control->vd[idx].owner = NULL;
128 }
129
130 snd_fasync_free(ctl->fasync);
131 snd_ctl_empty_read_queue(ctl);
132 put_pid(ctl->pid);
133 kfree(ctl);
134 module_put(card->module);
135 snd_card_file_remove(card, file);
136 return 0;
137 }
138
139 /**
140 * snd_ctl_notify - Send notification to user-space for a control change
141 * @card: the card to send notification
142 * @mask: the event mask, SNDRV_CTL_EVENT_*
143 * @id: the ctl element id to send notification
144 *
145 * This function adds an event record with the given id and mask, appends
146 * to the list and wakes up the user-space for notification. This can be
147 * called in the atomic context.
148 */
149 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
150 struct snd_ctl_elem_id *id)
151 {
152 struct snd_ctl_file *ctl;
153 struct snd_kctl_event *ev;
154
155 if (snd_BUG_ON(!card || !id))
156 return;
157 if (card->shutdown)
158 return;
159
160 guard(read_lock_irqsave)(&card->ctl_files_rwlock);
161 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
162 card->mixer_oss_change_count++;
163 #endif
164 list_for_each_entry(ctl, &card->ctl_files, list) {
165 if (!ctl->subscribed)
166 continue;
167 scoped_guard(spinlock, &ctl->read_lock) {
168 list_for_each_entry(ev, &ctl->events, list) {
169 if (ev->id.numid == id->numid) {
170 ev->mask |= mask;
171 goto _found;
172 }
173 }
174 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
175 if (ev) {
176 ev->id = *id;
177 ev->mask = mask;
178 list_add_tail(&ev->list, &ctl->events);
179 } else {
180 dev_err(card->dev, "No memory available to allocate event\n");
181 }
182 _found:
183 wake_up(&ctl->change_sleep);
184 }
185 snd_kill_fasync(ctl->fasync, SIGIO, POLL_IN);
186 }
187 }
188 EXPORT_SYMBOL(snd_ctl_notify);
189
190 /**
191 * snd_ctl_notify_one - Send notification to user-space for a control change
192 * @card: the card to send notification
193 * @mask: the event mask, SNDRV_CTL_EVENT_*
194 * @kctl: the pointer with the control instance
195 * @ioff: the additional offset to the control index
196 *
197 * This function calls snd_ctl_notify() and does additional jobs
198 * like LED state changes.
199 */
200 void snd_ctl_notify_one(struct snd_card *card, unsigned int mask,
201 struct snd_kcontrol *kctl, unsigned int ioff)
202 {
203 struct snd_ctl_elem_id id = kctl->id;
204 struct snd_ctl_layer_ops *lops;
205
206 id.index += ioff;
207 id.numid += ioff;
208 snd_ctl_notify(card, mask, &id);
209 guard(rwsem_read)(&snd_ctl_layer_rwsem);
210 for (lops = snd_ctl_layer; lops; lops = lops->next)
211 lops->lnotify(card, mask, kctl, ioff);
212 }
213 EXPORT_SYMBOL(snd_ctl_notify_one);
214
215 /**
216 * snd_ctl_new - create a new control instance with some elements
217 * @kctl: the pointer to store new control instance
218 * @count: the number of elements in this control
219 * @access: the default access flags for elements in this control
220 * @file: given when locking these elements
221 *
222 * Allocates a memory object for a new control instance. The instance has
223 * elements as many as the given number (@count). Each element has given
224 * access permissions (@access). Each element is locked when @file is given.
225 *
226 * Return: 0 on success, error code on failure
227 */
228 static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
229 unsigned int access, struct snd_ctl_file *file)
230 {
231 unsigned int idx;
232
233 if (count == 0 || count > MAX_CONTROL_COUNT)
234 return -EINVAL;
235
236 *kctl = kzalloc(struct_size(*kctl, vd, count), GFP_KERNEL);
237 if (!*kctl)
238 return -ENOMEM;
239
240 for (idx = 0; idx < count; idx++) {
241 (*kctl)->vd[idx].access = access;
242 (*kctl)->vd[idx].owner = file;
243 }
244 (*kctl)->count = count;
245
246 return 0;
247 }
248
249 /**
250 * snd_ctl_new1 - create a control instance from the template
251 * @ncontrol: the initialization record
252 * @private_data: the private data to set
253 *
254 * Allocates a new struct snd_kcontrol instance and initialize from the given
255 * template. When the access field of ncontrol is 0, it's assumed as
256 * READWRITE access. When the count field is 0, it's assumes as one.
257 *
258 * Return: The pointer of the newly generated instance, or %NULL on failure.
259 */
260 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
261 void *private_data)
262 {
263 struct snd_kcontrol *kctl;
264 unsigned int count;
265 unsigned int access;
266 int err;
267
268 if (snd_BUG_ON(!ncontrol || !ncontrol->info))
269 return NULL;
270
271 count = ncontrol->count;
272 if (count == 0)
273 count = 1;
274
275 access = ncontrol->access;
276 if (access == 0)
277 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
278 access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
279 SNDRV_CTL_ELEM_ACCESS_VOLATILE |
280 SNDRV_CTL_ELEM_ACCESS_INACTIVE |
281 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
282 SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
283 SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK |
284 SNDRV_CTL_ELEM_ACCESS_LED_MASK |
285 SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK);
286
287 err = snd_ctl_new(&kctl, count, access, NULL);
288 if (err < 0)
289 return NULL;
290
291 /* The 'numid' member is decided when calling snd_ctl_add(). */
292 kctl->id.iface = ncontrol->iface;
293 kctl->id.device = ncontrol->device;
294 kctl->id.subdevice = ncontrol->subdevice;
295 if (ncontrol->name) {
296 strscpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
297 if (strcmp(ncontrol->name, kctl->id.name) != 0)
298 pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
299 ncontrol->name, kctl->id.name);
300 }
301 kctl->id.index = ncontrol->index;
302
303 kctl->info = ncontrol->info;
304 kctl->get = ncontrol->get;
305 kctl->put = ncontrol->put;
306 kctl->tlv.p = ncontrol->tlv.p;
307
308 kctl->private_value = ncontrol->private_value;
309 kctl->private_data = private_data;
310
311 return kctl;
312 }
313 EXPORT_SYMBOL(snd_ctl_new1);
314
315 /**
316 * snd_ctl_free_one - release the control instance
317 * @kcontrol: the control instance
318 *
319 * Releases the control instance created via snd_ctl_new()
320 * or snd_ctl_new1().
321 * Don't call this after the control was added to the card.
322 */
323 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
324 {
325 if (kcontrol) {
326 if (kcontrol->private_free)
327 kcontrol->private_free(kcontrol);
328 kfree(kcontrol);
329 }
330 }
331 EXPORT_SYMBOL(snd_ctl_free_one);
332
333 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
334 unsigned int count)
335 {
336 struct snd_kcontrol *kctl;
337
338 /* Make sure that the ids assigned to the control do not wrap around */
339 if (card->last_numid >= UINT_MAX - count)
340 card->last_numid = 0;
341
342 list_for_each_entry(kctl, &card->controls, list) {
343 if (kctl->id.numid < card->last_numid + 1 + count &&
344 kctl->id.numid + kctl->count > card->last_numid + 1) {
345 card->last_numid = kctl->id.numid + kctl->count - 1;
346 return true;
347 }
348 }
349 return false;
350 }
351
352 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
353 {
354 unsigned int iter = 100000;
355
356 while (snd_ctl_remove_numid_conflict(card, count)) {
357 if (--iter == 0) {
358 /* this situation is very unlikely */
359 dev_err(card->dev, "unable to allocate new control numid\n");
360 return -ENOMEM;
361 }
362 }
363 return 0;
364 }
365
366 /* check whether the given id is contained in the given kctl */
367 static bool elem_id_matches(const struct snd_kcontrol *kctl,
368 const struct snd_ctl_elem_id *id)
369 {
370 return kctl->id.iface == id->iface &&
371 kctl->id.device == id->device &&
372 kctl->id.subdevice == id->subdevice &&
373 !strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)) &&
374 kctl->id.index <= id->index &&
375 kctl->id.index + kctl->count > id->index;
376 }
377
378 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
379 /* Compute a hash key for the corresponding ctl id
380 * It's for the name lookup, hence the numid is excluded.
381 * The hash key is bound in LONG_MAX to be used for Xarray key.
382 */
383 #define MULTIPLIER 37
384 static unsigned long get_ctl_id_hash(const struct snd_ctl_elem_id *id)
385 {
386 int i;
387 unsigned long h;
388
389 h = id->iface;
390 h = MULTIPLIER * h + id->device;
391 h = MULTIPLIER * h + id->subdevice;
392 for (i = 0; i < SNDRV_CTL_ELEM_ID_NAME_MAXLEN && id->name[i]; i++)
393 h = MULTIPLIER * h + id->name[i];
394 h = MULTIPLIER * h + id->index;
395 h &= LONG_MAX;
396 return h;
397 }
398
399 /* add hash entries to numid and ctl xarray tables */
400 static void add_hash_entries(struct snd_card *card,
401 struct snd_kcontrol *kcontrol)
402 {
403 struct snd_ctl_elem_id id = kcontrol->id;
404 int i;
405
406 xa_store_range(&card->ctl_numids, kcontrol->id.numid,
407 kcontrol->id.numid + kcontrol->count - 1,
408 kcontrol, GFP_KERNEL);
409
410 for (i = 0; i < kcontrol->count; i++) {
411 id.index = kcontrol->id.index + i;
412 if (xa_insert(&card->ctl_hash, get_ctl_id_hash(&id),
413 kcontrol, GFP_KERNEL)) {
414 /* skip hash for this entry, noting we had collision */
415 card->ctl_hash_collision = true;
416 dev_dbg(card->dev, "ctl_hash collision %d:%s:%d\n",
417 id.iface, id.name, id.index);
418 }
419 }
420 }
421
422 /* remove hash entries that have been added */
423 static void remove_hash_entries(struct snd_card *card,
424 struct snd_kcontrol *kcontrol)
425 {
426 struct snd_ctl_elem_id id = kcontrol->id;
427 struct snd_kcontrol *matched;
428 unsigned long h;
429 int i;
430
431 for (i = 0; i < kcontrol->count; i++) {
432 xa_erase(&card->ctl_numids, id.numid);
433 h = get_ctl_id_hash(&id);
434 matched = xa_load(&card->ctl_hash, h);
435 if (matched && (matched == kcontrol ||
436 elem_id_matches(matched, &id)))
437 xa_erase(&card->ctl_hash, h);
438 id.index++;
439 id.numid++;
440 }
441 }
442 #else /* CONFIG_SND_CTL_FAST_LOOKUP */
443 static inline void add_hash_entries(struct snd_card *card,
444 struct snd_kcontrol *kcontrol)
445 {
446 }
447 static inline void remove_hash_entries(struct snd_card *card,
448 struct snd_kcontrol *kcontrol)
449 {
450 }
451 #endif /* CONFIG_SND_CTL_FAST_LOOKUP */
452
453 enum snd_ctl_add_mode {
454 CTL_ADD_EXCLUSIVE, CTL_REPLACE, CTL_ADD_ON_REPLACE,
455 };
456
457 /* add/replace a new kcontrol object; call with card->controls_rwsem locked */
458 static int __snd_ctl_add_replace(struct snd_card *card,
459 struct snd_kcontrol *kcontrol,
460 enum snd_ctl_add_mode mode)
461 {
462 struct snd_ctl_elem_id id;
463 unsigned int idx;
464 struct snd_kcontrol *old;
465 int err;
466
467 lockdep_assert_held_write(&card->controls_rwsem);
468
469 id = kcontrol->id;
470 if (id.index > UINT_MAX - kcontrol->count)
471 return -EINVAL;
472
473 old = snd_ctl_find_id_locked(card, &id);
474 if (!old) {
475 if (mode == CTL_REPLACE)
476 return -EINVAL;
477 } else {
478 if (mode == CTL_ADD_EXCLUSIVE) {
479 dev_err(card->dev,
480 "control %i:%i:%i:%s:%i is already present\n",
481 id.iface, id.device, id.subdevice, id.name,
482 id.index);
483 return -EBUSY;
484 }
485
486 err = snd_ctl_remove_locked(card, old);
487 if (err < 0)
488 return err;
489 }
490
491 if (snd_ctl_find_hole(card, kcontrol->count) < 0)
492 return -ENOMEM;
493
494 list_add_tail(&kcontrol->list, &card->controls);
495 card->controls_count += kcontrol->count;
496 kcontrol->id.numid = card->last_numid + 1;
497 card->last_numid += kcontrol->count;
498
499 add_hash_entries(card, kcontrol);
500
501 for (idx = 0; idx < kcontrol->count; idx++)
502 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_ADD, kcontrol, idx);
503
504 return 0;
505 }
506
507 static int snd_ctl_add_replace(struct snd_card *card,
508 struct snd_kcontrol *kcontrol,
509 enum snd_ctl_add_mode mode)
510 {
511 int err = -EINVAL;
512
513 if (! kcontrol)
514 return err;
515 if (snd_BUG_ON(!card || !kcontrol->info))
516 goto error;
517
518 scoped_guard(rwsem_write, &card->controls_rwsem)
519 err = __snd_ctl_add_replace(card, kcontrol, mode);
520
521 if (err < 0)
522 goto error;
523 return 0;
524
525 error:
526 snd_ctl_free_one(kcontrol);
527 return err;
528 }
529
530 /**
531 * snd_ctl_add - add the control instance to the card
532 * @card: the card instance
533 * @kcontrol: the control instance to add
534 *
535 * Adds the control instance created via snd_ctl_new() or
536 * snd_ctl_new1() to the given card. Assigns also an unique
537 * numid used for fast search.
538 *
539 * It frees automatically the control which cannot be added.
540 *
541 * Return: Zero if successful, or a negative error code on failure.
542 *
543 */
544 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
545 {
546 return snd_ctl_add_replace(card, kcontrol, CTL_ADD_EXCLUSIVE);
547 }
548 EXPORT_SYMBOL(snd_ctl_add);
549
550 /**
551 * snd_ctl_replace - replace the control instance of the card
552 * @card: the card instance
553 * @kcontrol: the control instance to replace
554 * @add_on_replace: add the control if not already added
555 *
556 * Replaces the given control. If the given control does not exist
557 * and the add_on_replace flag is set, the control is added. If the
558 * control exists, it is destroyed first.
559 *
560 * It frees automatically the control which cannot be added or replaced.
561 *
562 * Return: Zero if successful, or a negative error code on failure.
563 */
564 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
565 bool add_on_replace)
566 {
567 return snd_ctl_add_replace(card, kcontrol,
568 add_on_replace ? CTL_ADD_ON_REPLACE : CTL_REPLACE);
569 }
570 EXPORT_SYMBOL(snd_ctl_replace);
571
572 static int __snd_ctl_remove(struct snd_card *card,
573 struct snd_kcontrol *kcontrol,
574 bool remove_hash)
575 {
576 unsigned int idx;
577
578 lockdep_assert_held_write(&card->controls_rwsem);
579
580 if (snd_BUG_ON(!card || !kcontrol))
581 return -EINVAL;
582 list_del(&kcontrol->list);
583
584 if (remove_hash)
585 remove_hash_entries(card, kcontrol);
586
587 card->controls_count -= kcontrol->count;
588 for (idx = 0; idx < kcontrol->count; idx++)
589 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_REMOVE, kcontrol, idx);
590 snd_ctl_free_one(kcontrol);
591 return 0;
592 }
593
594 static inline int snd_ctl_remove_locked(struct snd_card *card,
595 struct snd_kcontrol *kcontrol)
596 {
597 return __snd_ctl_remove(card, kcontrol, true);
598 }
599
600 /**
601 * snd_ctl_remove - remove the control from the card and release it
602 * @card: the card instance
603 * @kcontrol: the control instance to remove
604 *
605 * Removes the control from the card and then releases the instance.
606 * You don't need to call snd_ctl_free_one().
607 * Passing NULL to @kcontrol argument is allowed as noop.
608 *
609 * Return: 0 if successful, or a negative error code on failure.
610 *
611 * Note that this function takes card->controls_rwsem lock internally.
612 */
613 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
614 {
615 if (!kcontrol)
616 return 0;
617 guard(rwsem_write)(&card->controls_rwsem);
618 return snd_ctl_remove_locked(card, kcontrol);
619 }
620 EXPORT_SYMBOL(snd_ctl_remove);
621
622 /**
623 * snd_ctl_remove_id - remove the control of the given id and release it
624 * @card: the card instance
625 * @id: the control id to remove
626 *
627 * Finds the control instance with the given id, removes it from the
628 * card list and releases it.
629 *
630 * Return: 0 if successful, or a negative error code on failure.
631 */
632 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
633 {
634 struct snd_kcontrol *kctl;
635
636 guard(rwsem_write)(&card->controls_rwsem);
637 kctl = snd_ctl_find_id_locked(card, id);
638 if (kctl == NULL)
639 return -ENOENT;
640 return snd_ctl_remove_locked(card, kctl);
641 }
642 EXPORT_SYMBOL(snd_ctl_remove_id);
643
644 /**
645 * snd_ctl_remove_user_ctl - remove and release the unlocked user control
646 * @file: active control handle
647 * @id: the control id to remove
648 *
649 * Finds the control instance with the given id, removes it from the
650 * card list and releases it.
651 *
652 * Return: 0 if successful, or a negative error code on failure.
653 */
654 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
655 struct snd_ctl_elem_id *id)
656 {
657 struct snd_card *card = file->card;
658 struct snd_kcontrol *kctl;
659 int idx;
660
661 guard(rwsem_write)(&card->controls_rwsem);
662 kctl = snd_ctl_find_id_locked(card, id);
663 if (kctl == NULL)
664 return -ENOENT;
665 if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER))
666 return -EINVAL;
667 for (idx = 0; idx < kctl->count; idx++)
668 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file)
669 return -EBUSY;
670 return snd_ctl_remove_locked(card, kctl);
671 }
672
673 /**
674 * snd_ctl_activate_id - activate/inactivate the control of the given id
675 * @card: the card instance
676 * @id: the control id to activate/inactivate
677 * @active: non-zero to activate
678 *
679 * Finds the control instance with the given id, and activate or
680 * inactivate the control together with notification, if changed.
681 * The given ID data is filled with full information.
682 *
683 * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
684 */
685 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
686 int active)
687 {
688 struct snd_kcontrol *kctl;
689 struct snd_kcontrol_volatile *vd;
690 unsigned int index_offset;
691 int ret;
692
693 down_write(&card->controls_rwsem);
694 kctl = snd_ctl_find_id_locked(card, id);
695 if (kctl == NULL) {
696 ret = -ENOENT;
697 goto unlock;
698 }
699 index_offset = snd_ctl_get_ioff(kctl, id);
700 vd = &kctl->vd[index_offset];
701 ret = 0;
702 if (active) {
703 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
704 goto unlock;
705 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
706 } else {
707 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
708 goto unlock;
709 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
710 }
711 snd_ctl_build_ioff(id, kctl, index_offset);
712 downgrade_write(&card->controls_rwsem);
713 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_INFO, kctl, index_offset);
714 up_read(&card->controls_rwsem);
715 return 1;
716
717 unlock:
718 up_write(&card->controls_rwsem);
719 return ret;
720 }
721 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
722
723 /**
724 * snd_ctl_rename_id - replace the id of a control on the card
725 * @card: the card instance
726 * @src_id: the old id
727 * @dst_id: the new id
728 *
729 * Finds the control with the old id from the card, and replaces the
730 * id with the new one.
731 *
732 * The function tries to keep the already assigned numid while replacing
733 * the rest.
734 *
735 * Note that this function should be used only in the card initialization
736 * phase. Calling after the card instantiation may cause issues with
737 * user-space expecting persistent numids.
738 *
739 * Return: Zero if successful, or a negative error code on failure.
740 */
741 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
742 struct snd_ctl_elem_id *dst_id)
743 {
744 struct snd_kcontrol *kctl;
745 int saved_numid;
746
747 guard(rwsem_write)(&card->controls_rwsem);
748 kctl = snd_ctl_find_id_locked(card, src_id);
749 if (kctl == NULL)
750 return -ENOENT;
751 saved_numid = kctl->id.numid;
752 remove_hash_entries(card, kctl);
753 kctl->id = *dst_id;
754 kctl->id.numid = saved_numid;
755 add_hash_entries(card, kctl);
756 return 0;
757 }
758 EXPORT_SYMBOL(snd_ctl_rename_id);
759
760 /**
761 * snd_ctl_rename - rename the control on the card
762 * @card: the card instance
763 * @kctl: the control to rename
764 * @name: the new name
765 *
766 * Renames the specified control on the card to the new name.
767 *
768 * Note that this function takes card->controls_rwsem lock internally.
769 */
770 void snd_ctl_rename(struct snd_card *card, struct snd_kcontrol *kctl,
771 const char *name)
772 {
773 guard(rwsem_write)(&card->controls_rwsem);
774 remove_hash_entries(card, kctl);
775
776 if (strscpy(kctl->id.name, name, sizeof(kctl->id.name)) < 0)
777 pr_warn("ALSA: Renamed control new name '%s' truncated to '%s'\n",
778 name, kctl->id.name);
779
780 add_hash_entries(card, kctl);
781 }
782 EXPORT_SYMBOL(snd_ctl_rename);
783
784 #ifndef CONFIG_SND_CTL_FAST_LOOKUP
785 static struct snd_kcontrol *
786 snd_ctl_find_numid_slow(struct snd_card *card, unsigned int numid)
787 {
788 struct snd_kcontrol *kctl;
789
790 list_for_each_entry(kctl, &card->controls, list) {
791 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
792 return kctl;
793 }
794 return NULL;
795 }
796 #endif /* !CONFIG_SND_CTL_FAST_LOOKUP */
797
798 /**
799 * snd_ctl_find_numid_locked - find the control instance with the given number-id
800 * @card: the card instance
801 * @numid: the number-id to search
802 *
803 * Finds the control instance with the given number-id from the card.
804 *
805 * The caller must down card->controls_rwsem before calling this function
806 * (if the race condition can happen).
807 *
808 * Return: The pointer of the instance if found, or %NULL if not.
809 */
810 struct snd_kcontrol *
811 snd_ctl_find_numid_locked(struct snd_card *card, unsigned int numid)
812 {
813 if (snd_BUG_ON(!card || !numid))
814 return NULL;
815 lockdep_assert_held(&card->controls_rwsem);
816 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
817 return xa_load(&card->ctl_numids, numid);
818 #else
819 return snd_ctl_find_numid_slow(card, numid);
820 #endif
821 }
822 EXPORT_SYMBOL(snd_ctl_find_numid_locked);
823
824 /**
825 * snd_ctl_find_numid - find the control instance with the given number-id
826 * @card: the card instance
827 * @numid: the number-id to search
828 *
829 * Finds the control instance with the given number-id from the card.
830 *
831 * Return: The pointer of the instance if found, or %NULL if not.
832 *
833 * Note that this function takes card->controls_rwsem lock internally.
834 */
835 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card,
836 unsigned int numid)
837 {
838 guard(rwsem_read)(&card->controls_rwsem);
839 return snd_ctl_find_numid_locked(card, numid);
840 }
841 EXPORT_SYMBOL(snd_ctl_find_numid);
842
843 /**
844 * snd_ctl_find_id_locked - find the control instance with the given id
845 * @card: the card instance
846 * @id: the id to search
847 *
848 * Finds the control instance with the given id from the card.
849 *
850 * The caller must down card->controls_rwsem before calling this function
851 * (if the race condition can happen).
852 *
853 * Return: The pointer of the instance if found, or %NULL if not.
854 */
855 struct snd_kcontrol *snd_ctl_find_id_locked(struct snd_card *card,
856 const struct snd_ctl_elem_id *id)
857 {
858 struct snd_kcontrol *kctl;
859
860 if (snd_BUG_ON(!card || !id))
861 return NULL;
862 lockdep_assert_held(&card->controls_rwsem);
863 if (id->numid != 0)
864 return snd_ctl_find_numid_locked(card, id->numid);
865 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
866 kctl = xa_load(&card->ctl_hash, get_ctl_id_hash(id));
867 if (kctl && elem_id_matches(kctl, id))
868 return kctl;
869 if (!card->ctl_hash_collision)
870 return NULL; /* we can rely on only hash table */
871 #endif
872 /* no matching in hash table - try all as the last resort */
873 list_for_each_entry(kctl, &card->controls, list)
874 if (elem_id_matches(kctl, id))
875 return kctl;
876
877 return NULL;
878 }
879 EXPORT_SYMBOL(snd_ctl_find_id_locked);
880
881 /**
882 * snd_ctl_find_id - find the control instance with the given id
883 * @card: the card instance
884 * @id: the id to search
885 *
886 * Finds the control instance with the given id from the card.
887 *
888 * Return: The pointer of the instance if found, or %NULL if not.
889 *
890 * Note that this function takes card->controls_rwsem lock internally.
891 */
892 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
893 const struct snd_ctl_elem_id *id)
894 {
895 guard(rwsem_read)(&card->controls_rwsem);
896 return snd_ctl_find_id_locked(card, id);
897 }
898 EXPORT_SYMBOL(snd_ctl_find_id);
899
900 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
901 unsigned int cmd, void __user *arg)
902 {
903 struct snd_ctl_card_info *info __free(kfree) = NULL;
904
905 info = kzalloc(sizeof(*info), GFP_KERNEL);
906 if (! info)
907 return -ENOMEM;
908 scoped_guard(rwsem_read, &snd_ioctl_rwsem) {
909 info->card = card->number;
910 strscpy(info->id, card->id, sizeof(info->id));
911 strscpy(info->driver, card->driver, sizeof(info->driver));
912 strscpy(info->name, card->shortname, sizeof(info->name));
913 strscpy(info->longname, card->longname, sizeof(info->longname));
914 strscpy(info->mixername, card->mixername, sizeof(info->mixername));
915 strscpy(info->components, card->components, sizeof(info->components));
916 }
917 if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info)))
918 return -EFAULT;
919 return 0;
920 }
921
922 static int snd_ctl_elem_list(struct snd_card *card,
923 struct snd_ctl_elem_list *list)
924 {
925 struct snd_kcontrol *kctl;
926 struct snd_ctl_elem_id id;
927 unsigned int offset, space, jidx;
928
929 offset = list->offset;
930 space = list->space;
931
932 guard(rwsem_read)(&card->controls_rwsem);
933 list->count = card->controls_count;
934 list->used = 0;
935 if (!space)
936 return 0;
937 list_for_each_entry(kctl, &card->controls, list) {
938 if (offset >= kctl->count) {
939 offset -= kctl->count;
940 continue;
941 }
942 for (jidx = offset; jidx < kctl->count; jidx++) {
943 snd_ctl_build_ioff(&id, kctl, jidx);
944 if (copy_to_user(list->pids + list->used, &id, sizeof(id)))
945 return -EFAULT;
946 list->used++;
947 if (!--space)
948 return 0;
949 }
950 offset = 0;
951 }
952 return 0;
953 }
954
955 static int snd_ctl_elem_list_user(struct snd_card *card,
956 struct snd_ctl_elem_list __user *_list)
957 {
958 struct snd_ctl_elem_list list;
959 int err;
960
961 if (copy_from_user(&list, _list, sizeof(list)))
962 return -EFAULT;
963 err = snd_ctl_elem_list(card, &list);
964 if (err)
965 return err;
966 if (copy_to_user(_list, &list, sizeof(list)))
967 return -EFAULT;
968
969 return 0;
970 }
971
972 /* Check whether the given kctl info is valid */
973 static int snd_ctl_check_elem_info(struct snd_card *card,
974 const struct snd_ctl_elem_info *info)
975 {
976 static const unsigned int max_value_counts[] = {
977 [SNDRV_CTL_ELEM_TYPE_BOOLEAN] = 128,
978 [SNDRV_CTL_ELEM_TYPE_INTEGER] = 128,
979 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
980 [SNDRV_CTL_ELEM_TYPE_BYTES] = 512,
981 [SNDRV_CTL_ELEM_TYPE_IEC958] = 1,
982 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
983 };
984
985 if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
986 info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64) {
987 if (card)
988 dev_err(card->dev,
989 "control %i:%i:%i:%s:%i: invalid type %d\n",
990 info->id.iface, info->id.device,
991 info->id.subdevice, info->id.name,
992 info->id.index, info->type);
993 return -EINVAL;
994 }
995 if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
996 info->value.enumerated.items == 0) {
997 if (card)
998 dev_err(card->dev,
999 "control %i:%i:%i:%s:%i: zero enum items\n",
1000 info->id.iface, info->id.device,
1001 info->id.subdevice, info->id.name,
1002 info->id.index);
1003 return -EINVAL;
1004 }
1005 if (info->count > max_value_counts[info->type]) {
1006 if (card)
1007 dev_err(card->dev,
1008 "control %i:%i:%i:%s:%i: invalid count %d\n",
1009 info->id.iface, info->id.device,
1010 info->id.subdevice, info->id.name,
1011 info->id.index, info->count);
1012 return -EINVAL;
1013 }
1014
1015 return 0;
1016 }
1017
1018 /* The capacity of struct snd_ctl_elem_value.value.*/
1019 static const unsigned int value_sizes[] = {
1020 [SNDRV_CTL_ELEM_TYPE_BOOLEAN] = sizeof(long),
1021 [SNDRV_CTL_ELEM_TYPE_INTEGER] = sizeof(long),
1022 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
1023 [SNDRV_CTL_ELEM_TYPE_BYTES] = sizeof(unsigned char),
1024 [SNDRV_CTL_ELEM_TYPE_IEC958] = sizeof(struct snd_aes_iec958),
1025 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
1026 };
1027
1028 /* fill the remaining snd_ctl_elem_value data with the given pattern */
1029 static void fill_remaining_elem_value(struct snd_ctl_elem_value *control,
1030 struct snd_ctl_elem_info *info,
1031 u32 pattern)
1032 {
1033 size_t offset = value_sizes[info->type] * info->count;
1034
1035 offset = DIV_ROUND_UP(offset, sizeof(u32));
1036 memset32((u32 *)control->value.bytes.data + offset, pattern,
1037 sizeof(control->value) / sizeof(u32) - offset);
1038 }
1039
1040 /* check whether the given integer ctl value is valid */
1041 static int sanity_check_int_value(struct snd_card *card,
1042 const struct snd_ctl_elem_value *control,
1043 const struct snd_ctl_elem_info *info,
1044 int i, bool print_error)
1045 {
1046 long long lval, lmin, lmax, lstep;
1047 u64 rem;
1048
1049 switch (info->type) {
1050 default:
1051 case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
1052 lval = control->value.integer.value[i];
1053 lmin = 0;
1054 lmax = 1;
1055 lstep = 0;
1056 break;
1057 case SNDRV_CTL_ELEM_TYPE_INTEGER:
1058 lval = control->value.integer.value[i];
1059 lmin = info->value.integer.min;
1060 lmax = info->value.integer.max;
1061 lstep = info->value.integer.step;
1062 break;
1063 case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1064 lval = control->value.integer64.value[i];
1065 lmin = info->value.integer64.min;
1066 lmax = info->value.integer64.max;
1067 lstep = info->value.integer64.step;
1068 break;
1069 case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
1070 lval = control->value.enumerated.item[i];
1071 lmin = 0;
1072 lmax = info->value.enumerated.items - 1;
1073 lstep = 0;
1074 break;
1075 }
1076
1077 if (lval < lmin || lval > lmax) {
1078 if (print_error)
1079 dev_err(card->dev,
1080 "control %i:%i:%i:%s:%i: value out of range %lld (%lld/%lld) at count %i\n",
1081 control->id.iface, control->id.device,
1082 control->id.subdevice, control->id.name,
1083 control->id.index, lval, lmin, lmax, i);
1084 return -EINVAL;
1085 }
1086 if (lstep) {
1087 div64_u64_rem(lval, lstep, &rem);
1088 if (rem) {
1089 if (print_error)
1090 dev_err(card->dev,
1091 "control %i:%i:%i:%s:%i: unaligned value %lld (step %lld) at count %i\n",
1092 control->id.iface, control->id.device,
1093 control->id.subdevice, control->id.name,
1094 control->id.index, lval, lstep, i);
1095 return -EINVAL;
1096 }
1097 }
1098
1099 return 0;
1100 }
1101
1102 /* check whether the all input values are valid for the given elem value */
1103 static int sanity_check_input_values(struct snd_card *card,
1104 const struct snd_ctl_elem_value *control,
1105 const struct snd_ctl_elem_info *info,
1106 bool print_error)
1107 {
1108 int i, ret;
1109
1110 switch (info->type) {
1111 case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
1112 case SNDRV_CTL_ELEM_TYPE_INTEGER:
1113 case SNDRV_CTL_ELEM_TYPE_INTEGER64:
1114 case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
1115 for (i = 0; i < info->count; i++) {
1116 ret = sanity_check_int_value(card, control, info, i,
1117 print_error);
1118 if (ret < 0)
1119 return ret;
1120 }
1121 break;
1122 default:
1123 break;
1124 }
1125
1126 return 0;
1127 }
1128
1129 /* perform sanity checks to the given snd_ctl_elem_value object */
1130 static int sanity_check_elem_value(struct snd_card *card,
1131 const struct snd_ctl_elem_value *control,
1132 const struct snd_ctl_elem_info *info,
1133 u32 pattern)
1134 {
1135 size_t offset;
1136 int ret;
1137 u32 *p;
1138
1139 ret = sanity_check_input_values(card, control, info, true);
1140 if (ret < 0)
1141 return ret;
1142
1143 /* check whether the remaining area kept untouched */
1144 offset = value_sizes[info->type] * info->count;
1145 offset = DIV_ROUND_UP(offset, sizeof(u32));
1146 p = (u32 *)control->value.bytes.data + offset;
1147 for (; offset < sizeof(control->value) / sizeof(u32); offset++, p++) {
1148 if (*p != pattern) {
1149 ret = -EINVAL;
1150 break;
1151 }
1152 *p = 0; /* clear the checked area */
1153 }
1154
1155 return ret;
1156 }
1157
1158 static int __snd_ctl_elem_info(struct snd_card *card,
1159 struct snd_kcontrol *kctl,
1160 struct snd_ctl_elem_info *info,
1161 struct snd_ctl_file *ctl)
1162 {
1163 struct snd_kcontrol_volatile *vd;
1164 unsigned int index_offset;
1165 int result;
1166
1167 #ifdef CONFIG_SND_DEBUG
1168 info->access = 0;
1169 #endif
1170 result = kctl->info(kctl, info);
1171 if (result >= 0) {
1172 snd_BUG_ON(info->access);
1173 index_offset = snd_ctl_get_ioff(kctl, &info->id);
1174 vd = &kctl->vd[index_offset];
1175 snd_ctl_build_ioff(&info->id, kctl, index_offset);
1176 info->access = vd->access;
1177 if (vd->owner) {
1178 info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
1179 if (vd->owner == ctl)
1180 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
1181 info->owner = pid_vnr(vd->owner->pid);
1182 } else {
1183 info->owner = -1;
1184 }
1185 if (!snd_ctl_skip_validation(info) &&
1186 snd_ctl_check_elem_info(card, info) < 0)
1187 result = -EINVAL;
1188 }
1189 return result;
1190 }
1191
1192 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
1193 struct snd_ctl_elem_info *info)
1194 {
1195 struct snd_card *card = ctl->card;
1196 struct snd_kcontrol *kctl;
1197
1198 guard(rwsem_read)(&card->controls_rwsem);
1199 kctl = snd_ctl_find_id_locked(card, &info->id);
1200 if (!kctl)
1201 return -ENOENT;
1202 return __snd_ctl_elem_info(card, kctl, info, ctl);
1203 }
1204
1205 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
1206 struct snd_ctl_elem_info __user *_info)
1207 {
1208 struct snd_card *card = ctl->card;
1209 struct snd_ctl_elem_info info;
1210 int result;
1211
1212 if (copy_from_user(&info, _info, sizeof(info)))
1213 return -EFAULT;
1214 result = snd_power_ref_and_wait(card);
1215 if (result)
1216 return result;
1217 result = snd_ctl_elem_info(ctl, &info);
1218 snd_power_unref(card);
1219 if (result < 0)
1220 return result;
1221 /* drop internal access flags */
1222 info.access &= ~(SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK|
1223 SNDRV_CTL_ELEM_ACCESS_LED_MASK);
1224 if (copy_to_user(_info, &info, sizeof(info)))
1225 return -EFAULT;
1226 return result;
1227 }
1228
1229 static int snd_ctl_elem_read(struct snd_card *card,
1230 struct snd_ctl_elem_value *control)
1231 {
1232 struct snd_kcontrol *kctl;
1233 struct snd_kcontrol_volatile *vd;
1234 unsigned int index_offset;
1235 struct snd_ctl_elem_info info;
1236 const u32 pattern = 0xdeadbeef;
1237 int ret;
1238
1239 guard(rwsem_read)(&card->controls_rwsem);
1240 kctl = snd_ctl_find_id_locked(card, &control->id);
1241 if (!kctl)
1242 return -ENOENT;
1243
1244 index_offset = snd_ctl_get_ioff(kctl, &control->id);
1245 vd = &kctl->vd[index_offset];
1246 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) || !kctl->get)
1247 return -EPERM;
1248
1249 snd_ctl_build_ioff(&control->id, kctl, index_offset);
1250
1251 #ifdef CONFIG_SND_CTL_DEBUG
1252 /* info is needed only for validation */
1253 memset(&info, 0, sizeof(info));
1254 info.id = control->id;
1255 ret = __snd_ctl_elem_info(card, kctl, &info, NULL);
1256 if (ret < 0)
1257 return ret;
1258 #endif
1259
1260 if (!snd_ctl_skip_validation(&info))
1261 fill_remaining_elem_value(control, &info, pattern);
1262 ret = kctl->get(kctl, control);
1263 if (ret < 0)
1264 return ret;
1265 if (!snd_ctl_skip_validation(&info) &&
1266 sanity_check_elem_value(card, control, &info, pattern) < 0) {
1267 dev_err(card->dev,
1268 "control %i:%i:%i:%s:%i: access overflow\n",
1269 control->id.iface, control->id.device,
1270 control->id.subdevice, control->id.name,
1271 control->id.index);
1272 return -EINVAL;
1273 }
1274 return 0;
1275 }
1276
1277 static int snd_ctl_elem_read_user(struct snd_card *card,
1278 struct snd_ctl_elem_value __user *_control)
1279 {
1280 struct snd_ctl_elem_value *control __free(kfree) = NULL;
1281 int result;
1282
1283 control = memdup_user(_control, sizeof(*control));
1284 if (IS_ERR(control))
1285 return PTR_ERR(no_free_ptr(control));
1286
1287 result = snd_power_ref_and_wait(card);
1288 if (result)
1289 return result;
1290 result = snd_ctl_elem_read(card, control);
1291 snd_power_unref(card);
1292 if (result < 0)
1293 return result;
1294
1295 if (copy_to_user(_control, control, sizeof(*control)))
1296 return -EFAULT;
1297 return result;
1298 }
1299
1300 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
1301 struct snd_ctl_elem_value *control)
1302 {
1303 struct snd_kcontrol *kctl;
1304 struct snd_kcontrol_volatile *vd;
1305 unsigned int index_offset;
1306 int result = 0;
1307
1308 down_write(&card->controls_rwsem);
1309 kctl = snd_ctl_find_id_locked(card, &control->id);
1310 if (kctl == NULL) {
1311 up_write(&card->controls_rwsem);
1312 return -ENOENT;
1313 }
1314
1315 index_offset = snd_ctl_get_ioff(kctl, &control->id);
1316 vd = &kctl->vd[index_offset];
1317 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||
1318 (file && vd->owner && vd->owner != file)) {
1319 up_write(&card->controls_rwsem);
1320 return -EPERM;
1321 }
1322
1323 snd_ctl_build_ioff(&control->id, kctl, index_offset);
1324 /* validate input values */
1325 if (IS_ENABLED(CONFIG_SND_CTL_INPUT_VALIDATION)) {
1326 struct snd_ctl_elem_info info;
1327
1328 memset(&info, 0, sizeof(info));
1329 info.id = control->id;
1330 result = __snd_ctl_elem_info(card, kctl, &info, NULL);
1331 if (!result)
1332 result = sanity_check_input_values(card, control, &info,
1333 false);
1334 }
1335 if (!result)
1336 result = kctl->put(kctl, control);
1337 if (result < 0) {
1338 up_write(&card->controls_rwsem);
1339 return result;
1340 }
1341
1342 if (result > 0) {
1343 downgrade_write(&card->controls_rwsem);
1344 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_VALUE, kctl, index_offset);
1345 up_read(&card->controls_rwsem);
1346 } else {
1347 up_write(&card->controls_rwsem);
1348 }
1349
1350 return 0;
1351 }
1352
1353 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
1354 struct snd_ctl_elem_value __user *_control)
1355 {
1356 struct snd_ctl_elem_value *control __free(kfree) = NULL;
1357 struct snd_card *card;
1358 int result;
1359
1360 control = memdup_user(_control, sizeof(*control));
1361 if (IS_ERR(control))
1362 return PTR_ERR(no_free_ptr(control));
1363
1364 card = file->card;
1365 result = snd_power_ref_and_wait(card);
1366 if (result < 0)
1367 return result;
1368 result = snd_ctl_elem_write(card, file, control);
1369 snd_power_unref(card);
1370 if (result < 0)
1371 return result;
1372
1373 if (copy_to_user(_control, control, sizeof(*control)))
1374 return -EFAULT;
1375 return result;
1376 }
1377
1378 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
1379 struct snd_ctl_elem_id __user *_id)
1380 {
1381 struct snd_card *card = file->card;
1382 struct snd_ctl_elem_id id;
1383 struct snd_kcontrol *kctl;
1384 struct snd_kcontrol_volatile *vd;
1385
1386 if (copy_from_user(&id, _id, sizeof(id)))
1387 return -EFAULT;
1388 guard(rwsem_write)(&card->controls_rwsem);
1389 kctl = snd_ctl_find_id_locked(card, &id);
1390 if (!kctl)
1391 return -ENOENT;
1392 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1393 if (vd->owner)
1394 return -EBUSY;
1395 vd->owner = file;
1396 return 0;
1397 }
1398
1399 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
1400 struct snd_ctl_elem_id __user *_id)
1401 {
1402 struct snd_card *card = file->card;
1403 struct snd_ctl_elem_id id;
1404 struct snd_kcontrol *kctl;
1405 struct snd_kcontrol_volatile *vd;
1406
1407 if (copy_from_user(&id, _id, sizeof(id)))
1408 return -EFAULT;
1409 guard(rwsem_write)(&card->controls_rwsem);
1410 kctl = snd_ctl_find_id_locked(card, &id);
1411 if (!kctl)
1412 return -ENOENT;
1413 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1414 if (!vd->owner)
1415 return -EINVAL;
1416 if (vd->owner != file)
1417 return -EPERM;
1418 vd->owner = NULL;
1419 return 0;
1420 }
1421
1422 struct user_element {
1423 struct snd_ctl_elem_info info;
1424 struct snd_card *card;
1425 char *elem_data; /* element data */
1426 unsigned long elem_data_size; /* size of element data in bytes */
1427 void *tlv_data; /* TLV data */
1428 unsigned long tlv_data_size; /* TLV data size */
1429 void *priv_data; /* private data (like strings for enumerated type) */
1430 };
1431
1432 // check whether the addition (in bytes) of user ctl element may overflow the limit.
1433 static bool check_user_elem_overflow(struct snd_card *card, ssize_t add)
1434 {
1435 return (ssize_t)card->user_ctl_alloc_size + add > max_user_ctl_alloc_size;
1436 }
1437
1438 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1439 struct snd_ctl_elem_info *uinfo)
1440 {
1441 struct user_element *ue = kcontrol->private_data;
1442 unsigned int offset;
1443
1444 offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1445 *uinfo = ue->info;
1446 snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1447
1448 return 0;
1449 }
1450
1451 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1452 struct snd_ctl_elem_info *uinfo)
1453 {
1454 struct user_element *ue = kcontrol->private_data;
1455 const char *names;
1456 unsigned int item;
1457 unsigned int offset;
1458
1459 item = uinfo->value.enumerated.item;
1460
1461 offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1462 *uinfo = ue->info;
1463 snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1464
1465 item = min(item, uinfo->value.enumerated.items - 1);
1466 uinfo->value.enumerated.item = item;
1467
1468 names = ue->priv_data;
1469 for (; item > 0; --item)
1470 names += strlen(names) + 1;
1471 strcpy(uinfo->value.enumerated.name, names);
1472
1473 return 0;
1474 }
1475
1476 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1477 struct snd_ctl_elem_value *ucontrol)
1478 {
1479 struct user_element *ue = kcontrol->private_data;
1480 unsigned int size = ue->elem_data_size;
1481 char *src = ue->elem_data +
1482 snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1483
1484 memcpy(&ucontrol->value, src, size);
1485 return 0;
1486 }
1487
1488 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1489 struct snd_ctl_elem_value *ucontrol)
1490 {
1491 int err, change;
1492 struct user_element *ue = kcontrol->private_data;
1493 unsigned int size = ue->elem_data_size;
1494 char *dst = ue->elem_data +
1495 snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1496
1497 err = sanity_check_input_values(ue->card, ucontrol, &ue->info, false);
1498 if (err < 0)
1499 return err;
1500
1501 change = memcmp(&ucontrol->value, dst, size) != 0;
1502 if (change)
1503 memcpy(dst, &ucontrol->value, size);
1504 return change;
1505 }
1506
1507 /* called in controls_rwsem write lock */
1508 static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1509 unsigned int size)
1510 {
1511 struct user_element *ue = kctl->private_data;
1512 unsigned int *container;
1513 unsigned int mask = 0;
1514 int i;
1515 int change;
1516
1517 lockdep_assert_held_write(&ue->card->controls_rwsem);
1518
1519 if (size > 1024 * 128) /* sane value */
1520 return -EINVAL;
1521
1522 // does the TLV size change cause overflow?
1523 if (check_user_elem_overflow(ue->card, (ssize_t)(size - ue->tlv_data_size)))
1524 return -ENOMEM;
1525
1526 container = vmemdup_user(buf, size);
1527 if (IS_ERR(container))
1528 return PTR_ERR(container);
1529
1530 change = ue->tlv_data_size != size;
1531 if (!change)
1532 change = memcmp(ue->tlv_data, container, size) != 0;
1533 if (!change) {
1534 kvfree(container);
1535 return 0;
1536 }
1537
1538 if (ue->tlv_data == NULL) {
1539 /* Now TLV data is available. */
1540 for (i = 0; i < kctl->count; ++i)
1541 kctl->vd[i].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
1542 mask = SNDRV_CTL_EVENT_MASK_INFO;
1543 } else {
1544 ue->card->user_ctl_alloc_size -= ue->tlv_data_size;
1545 ue->tlv_data_size = 0;
1546 kvfree(ue->tlv_data);
1547 }
1548
1549 ue->tlv_data = container;
1550 ue->tlv_data_size = size;
1551 // decremented at private_free.
1552 ue->card->user_ctl_alloc_size += size;
1553
1554 mask |= SNDRV_CTL_EVENT_MASK_TLV;
1555 for (i = 0; i < kctl->count; ++i)
1556 snd_ctl_notify_one(ue->card, mask, kctl, i);
1557
1558 return change;
1559 }
1560
1561 static int read_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1562 unsigned int size)
1563 {
1564 struct user_element *ue = kctl->private_data;
1565
1566 if (ue->tlv_data_size == 0 || ue->tlv_data == NULL)
1567 return -ENXIO;
1568
1569 if (size < ue->tlv_data_size)
1570 return -ENOSPC;
1571
1572 if (copy_to_user(buf, ue->tlv_data, ue->tlv_data_size))
1573 return -EFAULT;
1574
1575 return 0;
1576 }
1577
1578 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kctl, int op_flag,
1579 unsigned int size, unsigned int __user *buf)
1580 {
1581 if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
1582 return replace_user_tlv(kctl, buf, size);
1583 else
1584 return read_user_tlv(kctl, buf, size);
1585 }
1586
1587 /* called in controls_rwsem write lock */
1588 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1589 {
1590 char *names, *p;
1591 size_t buf_len, name_len;
1592 unsigned int i;
1593 const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1594
1595 lockdep_assert_held_write(&ue->card->controls_rwsem);
1596
1597 buf_len = ue->info.value.enumerated.names_length;
1598 if (buf_len > 64 * 1024)
1599 return -EINVAL;
1600
1601 if (check_user_elem_overflow(ue->card, buf_len))
1602 return -ENOMEM;
1603 names = vmemdup_user((const void __user *)user_ptrval, buf_len);
1604 if (IS_ERR(names))
1605 return PTR_ERR(names);
1606
1607 /* check that there are enough valid names */
1608 p = names;
1609 for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1610 name_len = strnlen(p, buf_len);
1611 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1612 kvfree(names);
1613 return -EINVAL;
1614 }
1615 p += name_len + 1;
1616 buf_len -= name_len + 1;
1617 }
1618
1619 ue->priv_data = names;
1620 ue->info.value.enumerated.names_ptr = 0;
1621 // increment the allocation size; decremented again at private_free.
1622 ue->card->user_ctl_alloc_size += ue->info.value.enumerated.names_length;
1623
1624 return 0;
1625 }
1626
1627 static size_t compute_user_elem_size(size_t size, unsigned int count)
1628 {
1629 return sizeof(struct user_element) + size * count;
1630 }
1631
1632 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1633 {
1634 struct user_element *ue = kcontrol->private_data;
1635
1636 // decrement the allocation size.
1637 ue->card->user_ctl_alloc_size -= compute_user_elem_size(ue->elem_data_size, kcontrol->count);
1638 ue->card->user_ctl_alloc_size -= ue->tlv_data_size;
1639 if (ue->priv_data)
1640 ue->card->user_ctl_alloc_size -= ue->info.value.enumerated.names_length;
1641
1642 kvfree(ue->tlv_data);
1643 kvfree(ue->priv_data);
1644 kfree(ue);
1645 }
1646
1647 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1648 struct snd_ctl_elem_info *info, int replace)
1649 {
1650 struct snd_card *card = file->card;
1651 struct snd_kcontrol *kctl;
1652 unsigned int count;
1653 unsigned int access;
1654 long private_size;
1655 size_t alloc_size;
1656 struct user_element *ue;
1657 unsigned int offset;
1658 int err;
1659
1660 if (!*info->id.name)
1661 return -EINVAL;
1662 if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1663 return -EINVAL;
1664
1665 /* Delete a control to replace them if needed. */
1666 if (replace) {
1667 info->id.numid = 0;
1668 err = snd_ctl_remove_user_ctl(file, &info->id);
1669 if (err)
1670 return err;
1671 }
1672
1673 /* Check the number of elements for this userspace control. */
1674 count = info->owner;
1675 if (count == 0)
1676 count = 1;
1677
1678 /* Arrange access permissions if needed. */
1679 access = info->access;
1680 if (access == 0)
1681 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
1682 access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
1683 SNDRV_CTL_ELEM_ACCESS_INACTIVE |
1684 SNDRV_CTL_ELEM_ACCESS_TLV_WRITE);
1685
1686 /* In initial state, nothing is available as TLV container. */
1687 if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1688 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1689 access |= SNDRV_CTL_ELEM_ACCESS_USER;
1690
1691 /*
1692 * Check information and calculate the size of data specific to
1693 * this userspace control.
1694 */
1695 /* pass NULL to card for suppressing error messages */
1696 err = snd_ctl_check_elem_info(NULL, info);
1697 if (err < 0)
1698 return err;
1699 /* user-space control doesn't allow zero-size data */
1700 if (info->count < 1)
1701 return -EINVAL;
1702 private_size = value_sizes[info->type] * info->count;
1703 alloc_size = compute_user_elem_size(private_size, count);
1704
1705 guard(rwsem_write)(&card->controls_rwsem);
1706 if (check_user_elem_overflow(card, alloc_size))
1707 return -ENOMEM;
1708
1709 /*
1710 * Keep memory object for this userspace control. After passing this
1711 * code block, the instance should be freed by snd_ctl_free_one().
1712 *
1713 * Note that these elements in this control are locked.
1714 */
1715 err = snd_ctl_new(&kctl, count, access, file);
1716 if (err < 0)
1717 return err;
1718 memcpy(&kctl->id, &info->id, sizeof(kctl->id));
1719 ue = kzalloc(alloc_size, GFP_KERNEL);
1720 if (!ue) {
1721 kfree(kctl);
1722 return -ENOMEM;
1723 }
1724 kctl->private_data = ue;
1725 kctl->private_free = snd_ctl_elem_user_free;
1726
1727 // increment the allocated size; decremented again at private_free.
1728 card->user_ctl_alloc_size += alloc_size;
1729
1730 /* Set private data for this userspace control. */
1731 ue->card = card;
1732 ue->info = *info;
1733 ue->info.access = 0;
1734 ue->elem_data = (char *)ue + sizeof(*ue);
1735 ue->elem_data_size = private_size;
1736 if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1737 err = snd_ctl_elem_init_enum_names(ue);
1738 if (err < 0) {
1739 snd_ctl_free_one(kctl);
1740 return err;
1741 }
1742 }
1743
1744 /* Set callback functions. */
1745 if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1746 kctl->info = snd_ctl_elem_user_enum_info;
1747 else
1748 kctl->info = snd_ctl_elem_user_info;
1749 if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1750 kctl->get = snd_ctl_elem_user_get;
1751 if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1752 kctl->put = snd_ctl_elem_user_put;
1753 if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1754 kctl->tlv.c = snd_ctl_elem_user_tlv;
1755
1756 /* This function manage to free the instance on failure. */
1757 err = __snd_ctl_add_replace(card, kctl, CTL_ADD_EXCLUSIVE);
1758 if (err < 0) {
1759 snd_ctl_free_one(kctl);
1760 return err;
1761 }
1762 offset = snd_ctl_get_ioff(kctl, &info->id);
1763 snd_ctl_build_ioff(&info->id, kctl, offset);
1764 /*
1765 * Here we cannot fill any field for the number of elements added by
1766 * this operation because there're no specific fields. The usage of
1767 * 'owner' field for this purpose may cause any bugs to userspace
1768 * applications because the field originally means PID of a process
1769 * which locks the element.
1770 */
1771 return 0;
1772 }
1773
1774 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1775 struct snd_ctl_elem_info __user *_info, int replace)
1776 {
1777 struct snd_ctl_elem_info info;
1778 int err;
1779
1780 if (copy_from_user(&info, _info, sizeof(info)))
1781 return -EFAULT;
1782 err = snd_ctl_elem_add(file, &info, replace);
1783 if (err < 0)
1784 return err;
1785 if (copy_to_user(_info, &info, sizeof(info))) {
1786 snd_ctl_remove_user_ctl(file, &info.id);
1787 return -EFAULT;
1788 }
1789
1790 return 0;
1791 }
1792
1793 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1794 struct snd_ctl_elem_id __user *_id)
1795 {
1796 struct snd_ctl_elem_id id;
1797
1798 if (copy_from_user(&id, _id, sizeof(id)))
1799 return -EFAULT;
1800 return snd_ctl_remove_user_ctl(file, &id);
1801 }
1802
1803 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1804 {
1805 int subscribe;
1806 if (get_user(subscribe, ptr))
1807 return -EFAULT;
1808 if (subscribe < 0) {
1809 subscribe = file->subscribed;
1810 if (put_user(subscribe, ptr))
1811 return -EFAULT;
1812 return 0;
1813 }
1814 if (subscribe) {
1815 file->subscribed = 1;
1816 return 0;
1817 } else if (file->subscribed) {
1818 snd_ctl_empty_read_queue(file);
1819 file->subscribed = 0;
1820 }
1821 return 0;
1822 }
1823
1824 static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
1825 struct snd_kcontrol *kctl,
1826 struct snd_ctl_elem_id *id,
1827 unsigned int __user *buf, unsigned int size)
1828 {
1829 static const struct {
1830 int op;
1831 int perm;
1832 } pairs[] = {
1833 {SNDRV_CTL_TLV_OP_READ, SNDRV_CTL_ELEM_ACCESS_TLV_READ},
1834 {SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},
1835 {SNDRV_CTL_TLV_OP_CMD, SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},
1836 };
1837 struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1838 int i;
1839
1840 /* Check support of the request for this element. */
1841 for (i = 0; i < ARRAY_SIZE(pairs); ++i) {
1842 if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))
1843 break;
1844 }
1845 if (i == ARRAY_SIZE(pairs))
1846 return -ENXIO;
1847
1848 if (kctl->tlv.c == NULL)
1849 return -ENXIO;
1850
1851 /* Write and command operations are not allowed for locked element. */
1852 if (op_flag != SNDRV_CTL_TLV_OP_READ &&
1853 vd->owner != NULL && vd->owner != file)
1854 return -EPERM;
1855
1856 return kctl->tlv.c(kctl, op_flag, size, buf);
1857 }
1858
1859 static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,
1860 unsigned int __user *buf, unsigned int size)
1861 {
1862 struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1863 unsigned int len;
1864
1865 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ))
1866 return -ENXIO;
1867
1868 if (kctl->tlv.p == NULL)
1869 return -ENXIO;
1870
1871 len = sizeof(unsigned int) * 2 + kctl->tlv.p[1];
1872 if (size < len)
1873 return -ENOMEM;
1874
1875 if (copy_to_user(buf, kctl->tlv.p, len))
1876 return -EFAULT;
1877
1878 return 0;
1879 }
1880
1881 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1882 struct snd_ctl_tlv __user *buf,
1883 int op_flag)
1884 {
1885 struct snd_ctl_tlv header;
1886 unsigned int __user *container;
1887 unsigned int container_size;
1888 struct snd_kcontrol *kctl;
1889 struct snd_ctl_elem_id id;
1890 struct snd_kcontrol_volatile *vd;
1891
1892 lockdep_assert_held(&file->card->controls_rwsem);
1893
1894 if (copy_from_user(&header, buf, sizeof(header)))
1895 return -EFAULT;
1896
1897 /* In design of control core, numerical ID starts at 1. */
1898 if (header.numid == 0)
1899 return -EINVAL;
1900
1901 /* At least, container should include type and length fields. */
1902 if (header.length < sizeof(unsigned int) * 2)
1903 return -EINVAL;
1904 container_size = header.length;
1905 container = buf->tlv;
1906
1907 kctl = snd_ctl_find_numid_locked(file->card, header.numid);
1908 if (kctl == NULL)
1909 return -ENOENT;
1910
1911 /* Calculate index of the element in this set. */
1912 id = kctl->id;
1913 snd_ctl_build_ioff(&id, kctl, header.numid - id.numid);
1914 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1915
1916 if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1917 return call_tlv_handler(file, op_flag, kctl, &id, container,
1918 container_size);
1919 } else {
1920 if (op_flag == SNDRV_CTL_TLV_OP_READ) {
1921 return read_tlv_buf(kctl, &id, container,
1922 container_size);
1923 }
1924 }
1925
1926 /* Not supported. */
1927 return -ENXIO;
1928 }
1929
1930 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1931 {
1932 struct snd_ctl_file *ctl;
1933 struct snd_card *card;
1934 struct snd_kctl_ioctl *p;
1935 void __user *argp = (void __user *)arg;
1936 int __user *ip = argp;
1937 int err;
1938
1939 ctl = file->private_data;
1940 card = ctl->card;
1941 if (snd_BUG_ON(!card))
1942 return -ENXIO;
1943 switch (cmd) {
1944 case SNDRV_CTL_IOCTL_PVERSION:
1945 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1946 case SNDRV_CTL_IOCTL_CARD_INFO:
1947 return snd_ctl_card_info(card, ctl, cmd, argp);
1948 case SNDRV_CTL_IOCTL_ELEM_LIST:
1949 return snd_ctl_elem_list_user(card, argp);
1950 case SNDRV_CTL_IOCTL_ELEM_INFO:
1951 return snd_ctl_elem_info_user(ctl, argp);
1952 case SNDRV_CTL_IOCTL_ELEM_READ:
1953 return snd_ctl_elem_read_user(card, argp);
1954 case SNDRV_CTL_IOCTL_ELEM_WRITE:
1955 return snd_ctl_elem_write_user(ctl, argp);
1956 case SNDRV_CTL_IOCTL_ELEM_LOCK:
1957 return snd_ctl_elem_lock(ctl, argp);
1958 case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1959 return snd_ctl_elem_unlock(ctl, argp);
1960 case SNDRV_CTL_IOCTL_ELEM_ADD:
1961 return snd_ctl_elem_add_user(ctl, argp, 0);
1962 case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1963 return snd_ctl_elem_add_user(ctl, argp, 1);
1964 case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1965 return snd_ctl_elem_remove(ctl, argp);
1966 case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1967 return snd_ctl_subscribe_events(ctl, ip);
1968 case SNDRV_CTL_IOCTL_TLV_READ:
1969 err = snd_power_ref_and_wait(card);
1970 if (err < 0)
1971 return err;
1972 scoped_guard(rwsem_read, &card->controls_rwsem)
1973 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
1974 snd_power_unref(card);
1975 return err;
1976 case SNDRV_CTL_IOCTL_TLV_WRITE:
1977 err = snd_power_ref_and_wait(card);
1978 if (err < 0)
1979 return err;
1980 scoped_guard(rwsem_write, &card->controls_rwsem)
1981 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
1982 snd_power_unref(card);
1983 return err;
1984 case SNDRV_CTL_IOCTL_TLV_COMMAND:
1985 err = snd_power_ref_and_wait(card);
1986 if (err < 0)
1987 return err;
1988 scoped_guard(rwsem_write, &card->controls_rwsem)
1989 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
1990 snd_power_unref(card);
1991 return err;
1992 case SNDRV_CTL_IOCTL_POWER:
1993 return -ENOPROTOOPT;
1994 case SNDRV_CTL_IOCTL_POWER_STATE:
1995 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1996 }
1997
1998 guard(rwsem_read)(&snd_ioctl_rwsem);
1999 list_for_each_entry(p, &snd_control_ioctls, list) {
2000 err = p->fioctl(card, ctl, cmd, arg);
2001 if (err != -ENOIOCTLCMD)
2002 return err;
2003 }
2004 dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
2005 return -ENOTTY;
2006 }
2007
2008 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
2009 size_t count, loff_t * offset)
2010 {
2011 struct snd_ctl_file *ctl;
2012 int err = 0;
2013 ssize_t result = 0;
2014
2015 ctl = file->private_data;
2016 if (snd_BUG_ON(!ctl || !ctl->card))
2017 return -ENXIO;
2018 if (!ctl->subscribed)
2019 return -EBADFD;
2020 if (count < sizeof(struct snd_ctl_event))
2021 return -EINVAL;
2022 spin_lock_irq(&ctl->read_lock);
2023 while (count >= sizeof(struct snd_ctl_event)) {
2024 struct snd_ctl_event ev;
2025 struct snd_kctl_event *kev;
2026 while (list_empty(&ctl->events)) {
2027 wait_queue_entry_t wait;
2028 if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
2029 err = -EAGAIN;
2030 goto __end_lock;
2031 }
2032 init_waitqueue_entry(&wait, current);
2033 add_wait_queue(&ctl->change_sleep, &wait);
2034 set_current_state(TASK_INTERRUPTIBLE);
2035 spin_unlock_irq(&ctl->read_lock);
2036 schedule();
2037 remove_wait_queue(&ctl->change_sleep, &wait);
2038 if (ctl->card->shutdown)
2039 return -ENODEV;
2040 if (signal_pending(current))
2041 return -ERESTARTSYS;
2042 spin_lock_irq(&ctl->read_lock);
2043 }
2044 kev = snd_kctl_event(ctl->events.next);
2045 ev.type = SNDRV_CTL_EVENT_ELEM;
2046 ev.data.elem.mask = kev->mask;
2047 ev.data.elem.id = kev->id;
2048 list_del(&kev->list);
2049 spin_unlock_irq(&ctl->read_lock);
2050 kfree(kev);
2051 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
2052 err = -EFAULT;
2053 goto __end;
2054 }
2055 spin_lock_irq(&ctl->read_lock);
2056 buffer += sizeof(struct snd_ctl_event);
2057 count -= sizeof(struct snd_ctl_event);
2058 result += sizeof(struct snd_ctl_event);
2059 }
2060 __end_lock:
2061 spin_unlock_irq(&ctl->read_lock);
2062 __end:
2063 return result > 0 ? result : err;
2064 }
2065
2066 static __poll_t snd_ctl_poll(struct file *file, poll_table * wait)
2067 {
2068 __poll_t mask;
2069 struct snd_ctl_file *ctl;
2070
2071 ctl = file->private_data;
2072 if (!ctl->subscribed)
2073 return 0;
2074 poll_wait(file, &ctl->change_sleep, wait);
2075
2076 mask = 0;
2077 if (!list_empty(&ctl->events))
2078 mask |= EPOLLIN | EPOLLRDNORM;
2079
2080 return mask;
2081 }
2082
2083 /*
2084 * register the device-specific control-ioctls.
2085 * called from each device manager like pcm.c, hwdep.c, etc.
2086 */
2087 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
2088 {
2089 struct snd_kctl_ioctl *pn;
2090
2091 pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
2092 if (pn == NULL)
2093 return -ENOMEM;
2094 pn->fioctl = fcn;
2095 guard(rwsem_write)(&snd_ioctl_rwsem);
2096 list_add_tail(&pn->list, lists);
2097 return 0;
2098 }
2099
2100 /**
2101 * snd_ctl_register_ioctl - register the device-specific control-ioctls
2102 * @fcn: ioctl callback function
2103 *
2104 * called from each device manager like pcm.c, hwdep.c, etc.
2105 *
2106 * Return: zero if successful, or a negative error code
2107 */
2108 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
2109 {
2110 return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
2111 }
2112 EXPORT_SYMBOL(snd_ctl_register_ioctl);
2113
2114 #ifdef CONFIG_COMPAT
2115 /**
2116 * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
2117 * control-ioctls
2118 * @fcn: ioctl callback function
2119 *
2120 * Return: zero if successful, or a negative error code
2121 */
2122 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
2123 {
2124 return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
2125 }
2126 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
2127 #endif
2128
2129 /*
2130 * de-register the device-specific control-ioctls.
2131 */
2132 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
2133 struct list_head *lists)
2134 {
2135 struct snd_kctl_ioctl *p;
2136
2137 if (snd_BUG_ON(!fcn))
2138 return -EINVAL;
2139 guard(rwsem_write)(&snd_ioctl_rwsem);
2140 list_for_each_entry(p, lists, list) {
2141 if (p->fioctl == fcn) {
2142 list_del(&p->list);
2143 kfree(p);
2144 return 0;
2145 }
2146 }
2147 snd_BUG();
2148 return -EINVAL;
2149 }
2150
2151 /**
2152 * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
2153 * @fcn: ioctl callback function to unregister
2154 *
2155 * Return: zero if successful, or a negative error code
2156 */
2157 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
2158 {
2159 return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
2160 }
2161 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
2162
2163 #ifdef CONFIG_COMPAT
2164 /**
2165 * snd_ctl_unregister_ioctl_compat - de-register the device-specific compat
2166 * 32bit control-ioctls
2167 * @fcn: ioctl callback function to unregister
2168 *
2169 * Return: zero if successful, or a negative error code
2170 */
2171 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
2172 {
2173 return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
2174 }
2175 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
2176 #endif
2177
2178 static int snd_ctl_fasync(int fd, struct file * file, int on)
2179 {
2180 struct snd_ctl_file *ctl;
2181
2182 ctl = file->private_data;
2183 return snd_fasync_helper(fd, file, on, &ctl->fasync);
2184 }
2185
2186 /* return the preferred subdevice number if already assigned;
2187 * otherwise return -1
2188 */
2189 int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
2190 {
2191 struct snd_ctl_file *kctl;
2192 int subdevice = -1;
2193
2194 guard(read_lock_irqsave)(&card->ctl_files_rwlock);
2195 list_for_each_entry(kctl, &card->ctl_files, list) {
2196 if (kctl->pid == task_pid(current)) {
2197 subdevice = kctl->preferred_subdevice[type];
2198 if (subdevice != -1)
2199 break;
2200 }
2201 }
2202 return subdevice;
2203 }
2204 EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
2205
2206 /*
2207 * ioctl32 compat
2208 */
2209 #ifdef CONFIG_COMPAT
2210 #include "control_compat.c"
2211 #else
2212 #define snd_ctl_ioctl_compat NULL
2213 #endif
2214
2215 /*
2216 * control layers (audio LED etc.)
2217 */
2218
2219 /**
2220 * snd_ctl_request_layer - request to use the layer
2221 * @module_name: Name of the kernel module (NULL == build-in)
2222 *
2223 * Return: zero if successful, or an error code when the module cannot be loaded
2224 */
2225 int snd_ctl_request_layer(const char *module_name)
2226 {
2227 struct snd_ctl_layer_ops *lops;
2228
2229 if (module_name == NULL)
2230 return 0;
2231 scoped_guard(rwsem_read, &snd_ctl_layer_rwsem) {
2232 for (lops = snd_ctl_layer; lops; lops = lops->next)
2233 if (strcmp(lops->module_name, module_name) == 0)
2234 return 0;
2235 }
2236 return request_module(module_name);
2237 }
2238 EXPORT_SYMBOL_GPL(snd_ctl_request_layer);
2239
2240 /**
2241 * snd_ctl_register_layer - register new control layer
2242 * @lops: operation structure
2243 *
2244 * The new layer can track all control elements and do additional
2245 * operations on top (like audio LED handling).
2246 */
2247 void snd_ctl_register_layer(struct snd_ctl_layer_ops *lops)
2248 {
2249 struct snd_card *card;
2250 int card_number;
2251
2252 scoped_guard(rwsem_write, &snd_ctl_layer_rwsem) {
2253 lops->next = snd_ctl_layer;
2254 snd_ctl_layer = lops;
2255 }
2256 for (card_number = 0; card_number < SNDRV_CARDS; card_number++) {
2257 card = snd_card_ref(card_number);
2258 if (card) {
2259 scoped_guard(rwsem_read, &card->controls_rwsem)
2260 lops->lregister(card);
2261 snd_card_unref(card);
2262 }
2263 }
2264 }
2265 EXPORT_SYMBOL_GPL(snd_ctl_register_layer);
2266
2267 /**
2268 * snd_ctl_disconnect_layer - disconnect control layer
2269 * @lops: operation structure
2270 *
2271 * It is expected that the information about tracked cards
2272 * is freed before this call (the disconnect callback is
2273 * not called here).
2274 */
2275 void snd_ctl_disconnect_layer(struct snd_ctl_layer_ops *lops)
2276 {
2277 struct snd_ctl_layer_ops *lops2, *prev_lops2;
2278
2279 guard(rwsem_write)(&snd_ctl_layer_rwsem);
2280 for (lops2 = snd_ctl_layer, prev_lops2 = NULL; lops2; lops2 = lops2->next) {
2281 if (lops2 == lops) {
2282 if (!prev_lops2)
2283 snd_ctl_layer = lops->next;
2284 else
2285 prev_lops2->next = lops->next;
2286 break;
2287 }
2288 prev_lops2 = lops2;
2289 }
2290 }
2291 EXPORT_SYMBOL_GPL(snd_ctl_disconnect_layer);
2292
2293 /*
2294 * INIT PART
2295 */
2296
2297 static const struct file_operations snd_ctl_f_ops =
2298 {
2299 .owner = THIS_MODULE,
2300 .read = snd_ctl_read,
2301 .open = snd_ctl_open,
2302 .release = snd_ctl_release,
2303 .llseek = no_llseek,
2304 .poll = snd_ctl_poll,
2305 .unlocked_ioctl = snd_ctl_ioctl,
2306 .compat_ioctl = snd_ctl_ioctl_compat,
2307 .fasync = snd_ctl_fasync,
2308 };
2309
2310 /* call lops under rwsems; called from snd_ctl_dev_*() below() */
2311 #define call_snd_ctl_lops(_card, _op) \
2312 do { \
2313 struct snd_ctl_layer_ops *lops; \
2314 guard(rwsem_read)(&(_card)->controls_rwsem); \
2315 guard(rwsem_read)(&snd_ctl_layer_rwsem); \
2316 for (lops = snd_ctl_layer; lops; lops = lops->next) \
2317 lops->_op(_card); \
2318 } while (0)
2319
2320 /*
2321 * registration of the control device
2322 */
2323 static int snd_ctl_dev_register(struct snd_device *device)
2324 {
2325 struct snd_card *card = device->device_data;
2326 int err;
2327
2328 err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
2329 &snd_ctl_f_ops, card, card->ctl_dev);
2330 if (err < 0)
2331 return err;
2332 call_snd_ctl_lops(card, lregister);
2333 return 0;
2334 }
2335
2336 /*
2337 * disconnection of the control device
2338 */
2339 static int snd_ctl_dev_disconnect(struct snd_device *device)
2340 {
2341 struct snd_card *card = device->device_data;
2342 struct snd_ctl_file *ctl;
2343
2344 scoped_guard(read_lock_irqsave, &card->ctl_files_rwlock) {
2345 list_for_each_entry(ctl, &card->ctl_files, list) {
2346 wake_up(&ctl->change_sleep);
2347 snd_kill_fasync(ctl->fasync, SIGIO, POLL_ERR);
2348 }
2349 }
2350
2351 call_snd_ctl_lops(card, ldisconnect);
2352 return snd_unregister_device(card->ctl_dev);
2353 }
2354
2355 /*
2356 * free all controls
2357 */
2358 static int snd_ctl_dev_free(struct snd_device *device)
2359 {
2360 struct snd_card *card = device->device_data;
2361 struct snd_kcontrol *control;
2362
2363 scoped_guard(rwsem_write, &card->controls_rwsem) {
2364 while (!list_empty(&card->controls)) {
2365 control = snd_kcontrol(card->controls.next);
2366 __snd_ctl_remove(card, control, false);
2367 }
2368
2369 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
2370 xa_destroy(&card->ctl_numids);
2371 xa_destroy(&card->ctl_hash);
2372 #endif
2373 }
2374 put_device(card->ctl_dev);
2375 return 0;
2376 }
2377
2378 /*
2379 * create control core:
2380 * called from init.c
2381 */
2382 int snd_ctl_create(struct snd_card *card)
2383 {
2384 static const struct snd_device_ops ops = {
2385 .dev_free = snd_ctl_dev_free,
2386 .dev_register = snd_ctl_dev_register,
2387 .dev_disconnect = snd_ctl_dev_disconnect,
2388 };
2389 int err;
2390
2391 if (snd_BUG_ON(!card))
2392 return -ENXIO;
2393 if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
2394 return -ENXIO;
2395
2396 err = snd_device_alloc(&card->ctl_dev, card);
2397 if (err < 0)
2398 return err;
2399 dev_set_name(card->ctl_dev, "controlC%d", card->number);
2400
2401 err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
2402 if (err < 0)
2403 put_device(card->ctl_dev);
2404 return err;
2405 }
2406
2407 /*
2408 * Frequently used control callbacks/helpers
2409 */
2410
2411 /**
2412 * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
2413 * callback with a mono channel
2414 * @kcontrol: the kcontrol instance
2415 * @uinfo: info to store
2416 *
2417 * This is a function that can be used as info callback for a standard
2418 * boolean control with a single mono channel.
2419 *
2420 * Return: Zero (always successful)
2421 */
2422 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
2423 struct snd_ctl_elem_info *uinfo)
2424 {
2425 uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2426 uinfo->count = 1;
2427 uinfo->value.integer.min = 0;
2428 uinfo->value.integer.max = 1;
2429 return 0;
2430 }
2431 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
2432
2433 /**
2434 * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
2435 * callback with stereo two channels
2436 * @kcontrol: the kcontrol instance
2437 * @uinfo: info to store
2438 *
2439 * This is a function that can be used as info callback for a standard
2440 * boolean control with stereo two channels.
2441 *
2442 * Return: Zero (always successful)
2443 */
2444 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
2445 struct snd_ctl_elem_info *uinfo)
2446 {
2447 uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
2448 uinfo->count = 2;
2449 uinfo->value.integer.min = 0;
2450 uinfo->value.integer.max = 1;
2451 return 0;
2452 }
2453 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
2454
2455 /**
2456 * snd_ctl_enum_info - fills the info structure for an enumerated control
2457 * @info: the structure to be filled
2458 * @channels: the number of the control's channels; often one
2459 * @items: the number of control values; also the size of @names
2460 * @names: an array containing the names of all control values
2461 *
2462 * Sets all required fields in @info to their appropriate values.
2463 * If the control's accessibility is not the default (readable and writable),
2464 * the caller has to fill @info->access.
2465 *
2466 * Return: Zero (always successful)
2467 */
2468 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
2469 unsigned int items, const char *const names[])
2470 {
2471 info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
2472 info->count = channels;
2473 info->value.enumerated.items = items;
2474 if (!items)
2475 return 0;
2476 if (info->value.enumerated.item >= items)
2477 info->value.enumerated.item = items - 1;
2478 WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
2479 "ALSA: too long item name '%s'\n",
2480 names[info->value.enumerated.item]);
2481 strscpy(info->value.enumerated.name,
2482 names[info->value.enumerated.item],
2483 sizeof(info->value.enumerated.name));
2484 return 0;
2485 }
2486 EXPORT_SYMBOL(snd_ctl_enum_info);
2487
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