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/slab.h>
11 #include <linux/vmalloc.h>
12 #include <linux/time.h>
13 #include <linux/mm.h>
14 #include <linux/sched/signal.h>
15 #include <sound/core.h>
16 #include <sound/minors.h>
17 #include <sound/info.h>
18 #include <sound/control.h>
19
20 /* max number of user-defined controls */
21 #define MAX_USER_CONTROLS 32
22 #define MAX_CONTROL_COUNT 1028
23
24 struct snd_kctl_ioctl {
25 struct list_head list; /* list of all ioctls */
26 snd_kctl_ioctl_func_t fioctl;
27 };
28
29 static DECLARE_RWSEM(snd_ioctl_rwsem);
30 static LIST_HEAD(snd_control_ioctls);
31 #ifdef CONFIG_COMPAT
32 static LIST_HEAD(snd_control_compat_ioctls);
33 #endif
34
snd_ctl_open(struct inode * inode,struct file * file)35 static int snd_ctl_open(struct inode *inode, struct file *file)
36 {
37 unsigned long flags;
38 struct snd_card *card;
39 struct snd_ctl_file *ctl;
40 int i, err;
41
42 err = stream_open(inode, file);
43 if (err < 0)
44 return err;
45
46 card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
47 if (!card) {
48 err = -ENODEV;
49 goto __error1;
50 }
51 err = snd_card_file_add(card, file);
52 if (err < 0) {
53 err = -ENODEV;
54 goto __error1;
55 }
56 if (!try_module_get(card->module)) {
57 err = -EFAULT;
58 goto __error2;
59 }
60 ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
61 if (ctl == NULL) {
62 err = -ENOMEM;
63 goto __error;
64 }
65 INIT_LIST_HEAD(&ctl->events);
66 init_waitqueue_head(&ctl->change_sleep);
67 spin_lock_init(&ctl->read_lock);
68 ctl->card = card;
69 for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
70 ctl->preferred_subdevice[i] = -1;
71 ctl->pid = get_pid(task_pid(current));
72 file->private_data = ctl;
73 write_lock_irqsave(&card->ctl_files_rwlock, flags);
74 list_add_tail(&ctl->list, &card->ctl_files);
75 write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
76 snd_card_unref(card);
77 return 0;
78
79 __error:
80 module_put(card->module);
81 __error2:
82 snd_card_file_remove(card, file);
83 __error1:
84 if (card)
85 snd_card_unref(card);
86 return err;
87 }
88
snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)89 static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
90 {
91 unsigned long flags;
92 struct snd_kctl_event *cread;
93
94 spin_lock_irqsave(&ctl->read_lock, flags);
95 while (!list_empty(&ctl->events)) {
96 cread = snd_kctl_event(ctl->events.next);
97 list_del(&cread->list);
98 kfree(cread);
99 }
100 spin_unlock_irqrestore(&ctl->read_lock, flags);
101 }
102
snd_ctl_release(struct inode * inode,struct file * file)103 static int snd_ctl_release(struct inode *inode, struct file *file)
104 {
105 unsigned long flags;
106 struct snd_card *card;
107 struct snd_ctl_file *ctl;
108 struct snd_kcontrol *control;
109 unsigned int idx;
110
111 ctl = file->private_data;
112 file->private_data = NULL;
113 card = ctl->card;
114 write_lock_irqsave(&card->ctl_files_rwlock, flags);
115 list_del(&ctl->list);
116 write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
117 down_write(&card->controls_rwsem);
118 list_for_each_entry(control, &card->controls, list)
119 for (idx = 0; idx < control->count; idx++)
120 if (control->vd[idx].owner == ctl)
121 control->vd[idx].owner = NULL;
122 up_write(&card->controls_rwsem);
123 snd_ctl_empty_read_queue(ctl);
124 put_pid(ctl->pid);
125 kfree(ctl);
126 module_put(card->module);
127 snd_card_file_remove(card, file);
128 return 0;
129 }
130
131 /**
132 * snd_ctl_notify - Send notification to user-space for a control change
133 * @card: the card to send notification
134 * @mask: the event mask, SNDRV_CTL_EVENT_*
135 * @id: the ctl element id to send notification
136 *
137 * This function adds an event record with the given id and mask, appends
138 * to the list and wakes up the user-space for notification. This can be
139 * called in the atomic context.
140 */
snd_ctl_notify(struct snd_card * card,unsigned int mask,struct snd_ctl_elem_id * id)141 void snd_ctl_notify(struct snd_card *card, unsigned int mask,
142 struct snd_ctl_elem_id *id)
143 {
144 unsigned long flags;
145 struct snd_ctl_file *ctl;
146 struct snd_kctl_event *ev;
147
148 if (snd_BUG_ON(!card || !id))
149 return;
150 if (card->shutdown)
151 return;
152 read_lock(&card->ctl_files_rwlock);
153 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
154 card->mixer_oss_change_count++;
155 #endif
156 list_for_each_entry(ctl, &card->ctl_files, list) {
157 if (!ctl->subscribed)
158 continue;
159 spin_lock_irqsave(&ctl->read_lock, flags);
160 list_for_each_entry(ev, &ctl->events, list) {
161 if (ev->id.numid == id->numid) {
162 ev->mask |= mask;
163 goto _found;
164 }
165 }
166 ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
167 if (ev) {
168 ev->id = *id;
169 ev->mask = mask;
170 list_add_tail(&ev->list, &ctl->events);
171 } else {
172 dev_err(card->dev, "No memory available to allocate event\n");
173 }
174 _found:
175 wake_up(&ctl->change_sleep);
176 spin_unlock_irqrestore(&ctl->read_lock, flags);
177 kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
178 }
179 read_unlock(&card->ctl_files_rwlock);
180 }
181 EXPORT_SYMBOL(snd_ctl_notify);
182
183 /**
184 * snd_ctl_new - create a new control instance with some elements
185 * @kctl: the pointer to store new control instance
186 * @count: the number of elements in this control
187 * @access: the default access flags for elements in this control
188 * @file: given when locking these elements
189 *
190 * Allocates a memory object for a new control instance. The instance has
191 * elements as many as the given number (@count). Each element has given
192 * access permissions (@access). Each element is locked when @file is given.
193 *
194 * Return: 0 on success, error code on failure
195 */
snd_ctl_new(struct snd_kcontrol ** kctl,unsigned int count,unsigned int access,struct snd_ctl_file * file)196 static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
197 unsigned int access, struct snd_ctl_file *file)
198 {
199 unsigned int idx;
200
201 if (count == 0 || count > MAX_CONTROL_COUNT)
202 return -EINVAL;
203
204 *kctl = kzalloc(struct_size(*kctl, vd, count), GFP_KERNEL);
205 if (!*kctl)
206 return -ENOMEM;
207
208 for (idx = 0; idx < count; idx++) {
209 (*kctl)->vd[idx].access = access;
210 (*kctl)->vd[idx].owner = file;
211 }
212 (*kctl)->count = count;
213
214 return 0;
215 }
216
217 /**
218 * snd_ctl_new1 - create a control instance from the template
219 * @ncontrol: the initialization record
220 * @private_data: the private data to set
221 *
222 * Allocates a new struct snd_kcontrol instance and initialize from the given
223 * template. When the access field of ncontrol is 0, it's assumed as
224 * READWRITE access. When the count field is 0, it's assumes as one.
225 *
226 * Return: The pointer of the newly generated instance, or %NULL on failure.
227 */
snd_ctl_new1(const struct snd_kcontrol_new * ncontrol,void * private_data)228 struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
229 void *private_data)
230 {
231 struct snd_kcontrol *kctl;
232 unsigned int count;
233 unsigned int access;
234 int err;
235
236 if (snd_BUG_ON(!ncontrol || !ncontrol->info))
237 return NULL;
238
239 count = ncontrol->count;
240 if (count == 0)
241 count = 1;
242
243 access = ncontrol->access;
244 if (access == 0)
245 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
246 access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
247 SNDRV_CTL_ELEM_ACCESS_VOLATILE |
248 SNDRV_CTL_ELEM_ACCESS_INACTIVE |
249 SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
250 SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
251 SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK);
252
253 err = snd_ctl_new(&kctl, count, access, NULL);
254 if (err < 0)
255 return NULL;
256
257 /* The 'numid' member is decided when calling snd_ctl_add(). */
258 kctl->id.iface = ncontrol->iface;
259 kctl->id.device = ncontrol->device;
260 kctl->id.subdevice = ncontrol->subdevice;
261 if (ncontrol->name) {
262 strlcpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
263 if (strcmp(ncontrol->name, kctl->id.name) != 0)
264 pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
265 ncontrol->name, kctl->id.name);
266 }
267 kctl->id.index = ncontrol->index;
268
269 kctl->info = ncontrol->info;
270 kctl->get = ncontrol->get;
271 kctl->put = ncontrol->put;
272 kctl->tlv.p = ncontrol->tlv.p;
273
274 kctl->private_value = ncontrol->private_value;
275 kctl->private_data = private_data;
276
277 return kctl;
278 }
279 EXPORT_SYMBOL(snd_ctl_new1);
280
281 /**
282 * snd_ctl_free_one - release the control instance
283 * @kcontrol: the control instance
284 *
285 * Releases the control instance created via snd_ctl_new()
286 * or snd_ctl_new1().
287 * Don't call this after the control was added to the card.
288 */
snd_ctl_free_one(struct snd_kcontrol * kcontrol)289 void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
290 {
291 if (kcontrol) {
292 if (kcontrol->private_free)
293 kcontrol->private_free(kcontrol);
294 kfree(kcontrol);
295 }
296 }
297 EXPORT_SYMBOL(snd_ctl_free_one);
298
snd_ctl_remove_numid_conflict(struct snd_card * card,unsigned int count)299 static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
300 unsigned int count)
301 {
302 struct snd_kcontrol *kctl;
303
304 /* Make sure that the ids assigned to the control do not wrap around */
305 if (card->last_numid >= UINT_MAX - count)
306 card->last_numid = 0;
307
308 list_for_each_entry(kctl, &card->controls, list) {
309 if (kctl->id.numid < card->last_numid + 1 + count &&
310 kctl->id.numid + kctl->count > card->last_numid + 1) {
311 card->last_numid = kctl->id.numid + kctl->count - 1;
312 return true;
313 }
314 }
315 return false;
316 }
317
snd_ctl_find_hole(struct snd_card * card,unsigned int count)318 static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
319 {
320 unsigned int iter = 100000;
321
322 while (snd_ctl_remove_numid_conflict(card, count)) {
323 if (--iter == 0) {
324 /* this situation is very unlikely */
325 dev_err(card->dev, "unable to allocate new control numid\n");
326 return -ENOMEM;
327 }
328 }
329 return 0;
330 }
331
332 enum snd_ctl_add_mode {
333 CTL_ADD_EXCLUSIVE, CTL_REPLACE, CTL_ADD_ON_REPLACE,
334 };
335
336 /* add/replace a new kcontrol object; call with card->controls_rwsem locked */
__snd_ctl_add_replace(struct snd_card * card,struct snd_kcontrol * kcontrol,enum snd_ctl_add_mode mode)337 static int __snd_ctl_add_replace(struct snd_card *card,
338 struct snd_kcontrol *kcontrol,
339 enum snd_ctl_add_mode mode)
340 {
341 struct snd_ctl_elem_id id;
342 unsigned int idx;
343 unsigned int count;
344 struct snd_kcontrol *old;
345 int err;
346
347 id = kcontrol->id;
348 if (id.index > UINT_MAX - kcontrol->count)
349 return -EINVAL;
350
351 old = snd_ctl_find_id(card, &id);
352 if (!old) {
353 if (mode == CTL_REPLACE)
354 return -EINVAL;
355 } else {
356 if (mode == CTL_ADD_EXCLUSIVE) {
357 dev_err(card->dev,
358 "control %i:%i:%i:%s:%i is already present\n",
359 id.iface, id.device, id.subdevice, id.name,
360 id.index);
361 return -EBUSY;
362 }
363
364 err = snd_ctl_remove(card, old);
365 if (err < 0)
366 return err;
367 }
368
369 if (snd_ctl_find_hole(card, kcontrol->count) < 0)
370 return -ENOMEM;
371
372 list_add_tail(&kcontrol->list, &card->controls);
373 card->controls_count += kcontrol->count;
374 kcontrol->id.numid = card->last_numid + 1;
375 card->last_numid += kcontrol->count;
376
377 id = kcontrol->id;
378 count = kcontrol->count;
379 for (idx = 0; idx < count; idx++, id.index++, id.numid++)
380 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
381
382 return 0;
383 }
384
snd_ctl_add_replace(struct snd_card * card,struct snd_kcontrol * kcontrol,enum snd_ctl_add_mode mode)385 static int snd_ctl_add_replace(struct snd_card *card,
386 struct snd_kcontrol *kcontrol,
387 enum snd_ctl_add_mode mode)
388 {
389 int err = -EINVAL;
390
391 if (! kcontrol)
392 return err;
393 if (snd_BUG_ON(!card || !kcontrol->info))
394 goto error;
395
396 down_write(&card->controls_rwsem);
397 err = __snd_ctl_add_replace(card, kcontrol, mode);
398 up_write(&card->controls_rwsem);
399 if (err < 0)
400 goto error;
401 return 0;
402
403 error:
404 snd_ctl_free_one(kcontrol);
405 return err;
406 }
407
408 /**
409 * snd_ctl_add - add the control instance to the card
410 * @card: the card instance
411 * @kcontrol: the control instance to add
412 *
413 * Adds the control instance created via snd_ctl_new() or
414 * snd_ctl_new1() to the given card. Assigns also an unique
415 * numid used for fast search.
416 *
417 * It frees automatically the control which cannot be added.
418 *
419 * Return: Zero if successful, or a negative error code on failure.
420 *
421 */
snd_ctl_add(struct snd_card * card,struct snd_kcontrol * kcontrol)422 int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
423 {
424 return snd_ctl_add_replace(card, kcontrol, CTL_ADD_EXCLUSIVE);
425 }
426 EXPORT_SYMBOL(snd_ctl_add);
427
428 /**
429 * snd_ctl_replace - replace the control instance of the card
430 * @card: the card instance
431 * @kcontrol: the control instance to replace
432 * @add_on_replace: add the control if not already added
433 *
434 * Replaces the given control. If the given control does not exist
435 * and the add_on_replace flag is set, the control is added. If the
436 * control exists, it is destroyed first.
437 *
438 * It frees automatically the control which cannot be added or replaced.
439 *
440 * Return: Zero if successful, or a negative error code on failure.
441 */
snd_ctl_replace(struct snd_card * card,struct snd_kcontrol * kcontrol,bool add_on_replace)442 int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
443 bool add_on_replace)
444 {
445 return snd_ctl_add_replace(card, kcontrol,
446 add_on_replace ? CTL_ADD_ON_REPLACE : CTL_REPLACE);
447 }
448 EXPORT_SYMBOL(snd_ctl_replace);
449
450 /**
451 * snd_ctl_remove - remove the control from the card and release it
452 * @card: the card instance
453 * @kcontrol: the control instance to remove
454 *
455 * Removes the control from the card and then releases the instance.
456 * You don't need to call snd_ctl_free_one(). You must be in
457 * the write lock - down_write(&card->controls_rwsem).
458 *
459 * Return: 0 if successful, or a negative error code on failure.
460 */
snd_ctl_remove(struct snd_card * card,struct snd_kcontrol * kcontrol)461 int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
462 {
463 struct snd_ctl_elem_id id;
464 unsigned int idx;
465
466 if (snd_BUG_ON(!card || !kcontrol))
467 return -EINVAL;
468 list_del(&kcontrol->list);
469 card->controls_count -= kcontrol->count;
470 id = kcontrol->id;
471 for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
472 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
473 snd_ctl_free_one(kcontrol);
474 return 0;
475 }
476 EXPORT_SYMBOL(snd_ctl_remove);
477
478 /**
479 * snd_ctl_remove_id - remove the control of the given id and release it
480 * @card: the card instance
481 * @id: the control id to remove
482 *
483 * Finds the control instance with the given id, removes it from the
484 * card list and releases it.
485 *
486 * Return: 0 if successful, or a negative error code on failure.
487 */
snd_ctl_remove_id(struct snd_card * card,struct snd_ctl_elem_id * id)488 int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
489 {
490 struct snd_kcontrol *kctl;
491 int ret;
492
493 down_write(&card->controls_rwsem);
494 kctl = snd_ctl_find_id(card, id);
495 if (kctl == NULL) {
496 up_write(&card->controls_rwsem);
497 return -ENOENT;
498 }
499 ret = snd_ctl_remove(card, kctl);
500 up_write(&card->controls_rwsem);
501 return ret;
502 }
503 EXPORT_SYMBOL(snd_ctl_remove_id);
504
505 /**
506 * snd_ctl_remove_user_ctl - remove and release the unlocked user control
507 * @file: active control handle
508 * @id: the control id to remove
509 *
510 * Finds the control instance with the given id, removes it from the
511 * card list and releases it.
512 *
513 * Return: 0 if successful, or a negative error code on failure.
514 */
snd_ctl_remove_user_ctl(struct snd_ctl_file * file,struct snd_ctl_elem_id * id)515 static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
516 struct snd_ctl_elem_id *id)
517 {
518 struct snd_card *card = file->card;
519 struct snd_kcontrol *kctl;
520 int idx, ret;
521
522 down_write(&card->controls_rwsem);
523 kctl = snd_ctl_find_id(card, id);
524 if (kctl == NULL) {
525 ret = -ENOENT;
526 goto error;
527 }
528 if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
529 ret = -EINVAL;
530 goto error;
531 }
532 for (idx = 0; idx < kctl->count; idx++)
533 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
534 ret = -EBUSY;
535 goto error;
536 }
537 ret = snd_ctl_remove(card, kctl);
538 if (ret < 0)
539 goto error;
540 card->user_ctl_count--;
541 error:
542 up_write(&card->controls_rwsem);
543 return ret;
544 }
545
546 /**
547 * snd_ctl_activate_id - activate/inactivate the control of the given id
548 * @card: the card instance
549 * @id: the control id to activate/inactivate
550 * @active: non-zero to activate
551 *
552 * Finds the control instance with the given id, and activate or
553 * inactivate the control together with notification, if changed.
554 * The given ID data is filled with full information.
555 *
556 * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
557 */
snd_ctl_activate_id(struct snd_card * card,struct snd_ctl_elem_id * id,int active)558 int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
559 int active)
560 {
561 struct snd_kcontrol *kctl;
562 struct snd_kcontrol_volatile *vd;
563 unsigned int index_offset;
564 int ret;
565
566 down_write(&card->controls_rwsem);
567 kctl = snd_ctl_find_id(card, id);
568 if (kctl == NULL) {
569 ret = -ENOENT;
570 goto unlock;
571 }
572 index_offset = snd_ctl_get_ioff(kctl, id);
573 vd = &kctl->vd[index_offset];
574 ret = 0;
575 if (active) {
576 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
577 goto unlock;
578 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
579 } else {
580 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
581 goto unlock;
582 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
583 }
584 snd_ctl_build_ioff(id, kctl, index_offset);
585 ret = 1;
586 unlock:
587 up_write(&card->controls_rwsem);
588 if (ret > 0)
589 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
590 return ret;
591 }
592 EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
593
594 /**
595 * snd_ctl_rename_id - replace the id of a control on the card
596 * @card: the card instance
597 * @src_id: the old id
598 * @dst_id: the new id
599 *
600 * Finds the control with the old id from the card, and replaces the
601 * id with the new one.
602 *
603 * Return: Zero if successful, or a negative error code on failure.
604 */
snd_ctl_rename_id(struct snd_card * card,struct snd_ctl_elem_id * src_id,struct snd_ctl_elem_id * dst_id)605 int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
606 struct snd_ctl_elem_id *dst_id)
607 {
608 struct snd_kcontrol *kctl;
609
610 down_write(&card->controls_rwsem);
611 kctl = snd_ctl_find_id(card, src_id);
612 if (kctl == NULL) {
613 up_write(&card->controls_rwsem);
614 return -ENOENT;
615 }
616 kctl->id = *dst_id;
617 kctl->id.numid = card->last_numid + 1;
618 card->last_numid += kctl->count;
619 up_write(&card->controls_rwsem);
620 return 0;
621 }
622 EXPORT_SYMBOL(snd_ctl_rename_id);
623
624 /**
625 * snd_ctl_find_numid - find the control instance with the given number-id
626 * @card: the card instance
627 * @numid: the number-id to search
628 *
629 * Finds the control instance with the given number-id from the card.
630 *
631 * The caller must down card->controls_rwsem before calling this function
632 * (if the race condition can happen).
633 *
634 * Return: The pointer of the instance if found, or %NULL if not.
635 *
636 */
snd_ctl_find_numid(struct snd_card * card,unsigned int numid)637 struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
638 {
639 struct snd_kcontrol *kctl;
640
641 if (snd_BUG_ON(!card || !numid))
642 return NULL;
643 list_for_each_entry(kctl, &card->controls, list) {
644 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
645 return kctl;
646 }
647 return NULL;
648 }
649 EXPORT_SYMBOL(snd_ctl_find_numid);
650
651 /**
652 * snd_ctl_find_id - find the control instance with the given id
653 * @card: the card instance
654 * @id: the id to search
655 *
656 * Finds the control instance with the given id from the card.
657 *
658 * The caller must down card->controls_rwsem before calling this function
659 * (if the race condition can happen).
660 *
661 * Return: The pointer of the instance if found, or %NULL if not.
662 *
663 */
snd_ctl_find_id(struct snd_card * card,struct snd_ctl_elem_id * id)664 struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
665 struct snd_ctl_elem_id *id)
666 {
667 struct snd_kcontrol *kctl;
668
669 if (snd_BUG_ON(!card || !id))
670 return NULL;
671 if (id->numid != 0)
672 return snd_ctl_find_numid(card, id->numid);
673 list_for_each_entry(kctl, &card->controls, list) {
674 if (kctl->id.iface != id->iface)
675 continue;
676 if (kctl->id.device != id->device)
677 continue;
678 if (kctl->id.subdevice != id->subdevice)
679 continue;
680 if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
681 continue;
682 if (kctl->id.index > id->index)
683 continue;
684 if (kctl->id.index + kctl->count <= id->index)
685 continue;
686 return kctl;
687 }
688 return NULL;
689 }
690 EXPORT_SYMBOL(snd_ctl_find_id);
691
snd_ctl_card_info(struct snd_card * card,struct snd_ctl_file * ctl,unsigned int cmd,void __user * arg)692 static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
693 unsigned int cmd, void __user *arg)
694 {
695 struct snd_ctl_card_info *info;
696
697 info = kzalloc(sizeof(*info), GFP_KERNEL);
698 if (! info)
699 return -ENOMEM;
700 down_read(&snd_ioctl_rwsem);
701 info->card = card->number;
702 strlcpy(info->id, card->id, sizeof(info->id));
703 strlcpy(info->driver, card->driver, sizeof(info->driver));
704 strlcpy(info->name, card->shortname, sizeof(info->name));
705 strlcpy(info->longname, card->longname, sizeof(info->longname));
706 strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
707 strlcpy(info->components, card->components, sizeof(info->components));
708 up_read(&snd_ioctl_rwsem);
709 if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
710 kfree(info);
711 return -EFAULT;
712 }
713 kfree(info);
714 return 0;
715 }
716
snd_ctl_elem_list(struct snd_card * card,struct snd_ctl_elem_list __user * _list)717 static int snd_ctl_elem_list(struct snd_card *card,
718 struct snd_ctl_elem_list __user *_list)
719 {
720 struct snd_ctl_elem_list list;
721 struct snd_kcontrol *kctl;
722 struct snd_ctl_elem_id id;
723 unsigned int offset, space, jidx;
724 int err = 0;
725
726 if (copy_from_user(&list, _list, sizeof(list)))
727 return -EFAULT;
728 offset = list.offset;
729 space = list.space;
730
731 down_read(&card->controls_rwsem);
732 list.count = card->controls_count;
733 list.used = 0;
734 if (space > 0) {
735 list_for_each_entry(kctl, &card->controls, list) {
736 if (offset >= kctl->count) {
737 offset -= kctl->count;
738 continue;
739 }
740 for (jidx = offset; jidx < kctl->count; jidx++) {
741 snd_ctl_build_ioff(&id, kctl, jidx);
742 if (copy_to_user(list.pids + list.used, &id,
743 sizeof(id))) {
744 err = -EFAULT;
745 goto out;
746 }
747 list.used++;
748 if (!--space)
749 goto out;
750 }
751 offset = 0;
752 }
753 }
754 out:
755 up_read(&card->controls_rwsem);
756 if (!err && copy_to_user(_list, &list, sizeof(list)))
757 err = -EFAULT;
758 return err;
759 }
760
validate_element_member_dimension(struct snd_ctl_elem_info * info)761 static bool validate_element_member_dimension(struct snd_ctl_elem_info *info)
762 {
763 unsigned int members;
764 unsigned int i;
765
766 if (info->dimen.d[0] == 0)
767 return true;
768
769 members = 1;
770 for (i = 0; i < ARRAY_SIZE(info->dimen.d); ++i) {
771 if (info->dimen.d[i] == 0)
772 break;
773 members *= info->dimen.d[i];
774
775 /*
776 * info->count should be validated in advance, to guarantee
777 * calculation soundness.
778 */
779 if (members > info->count)
780 return false;
781 }
782
783 for (++i; i < ARRAY_SIZE(info->dimen.d); ++i) {
784 if (info->dimen.d[i] > 0)
785 return false;
786 }
787
788 return members == info->count;
789 }
790
snd_ctl_elem_info(struct snd_ctl_file * ctl,struct snd_ctl_elem_info * info)791 static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
792 struct snd_ctl_elem_info *info)
793 {
794 struct snd_card *card = ctl->card;
795 struct snd_kcontrol *kctl;
796 struct snd_kcontrol_volatile *vd;
797 unsigned int index_offset;
798 int result;
799
800 down_read(&card->controls_rwsem);
801 kctl = snd_ctl_find_id(card, &info->id);
802 if (kctl == NULL) {
803 up_read(&card->controls_rwsem);
804 return -ENOENT;
805 }
806 #ifdef CONFIG_SND_DEBUG
807 info->access = 0;
808 #endif
809 result = kctl->info(kctl, info);
810 if (result >= 0) {
811 snd_BUG_ON(info->access);
812 index_offset = snd_ctl_get_ioff(kctl, &info->id);
813 vd = &kctl->vd[index_offset];
814 snd_ctl_build_ioff(&info->id, kctl, index_offset);
815 info->access = vd->access;
816 if (vd->owner) {
817 info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
818 if (vd->owner == ctl)
819 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
820 info->owner = pid_vnr(vd->owner->pid);
821 } else {
822 info->owner = -1;
823 }
824 }
825 up_read(&card->controls_rwsem);
826 return result;
827 }
828
snd_ctl_elem_info_user(struct snd_ctl_file * ctl,struct snd_ctl_elem_info __user * _info)829 static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
830 struct snd_ctl_elem_info __user *_info)
831 {
832 struct snd_ctl_elem_info info;
833 int result;
834
835 if (copy_from_user(&info, _info, sizeof(info)))
836 return -EFAULT;
837 result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
838 if (result < 0)
839 return result;
840 result = snd_ctl_elem_info(ctl, &info);
841 if (result < 0)
842 return result;
843 if (copy_to_user(_info, &info, sizeof(info)))
844 return -EFAULT;
845 return result;
846 }
847
snd_ctl_elem_read(struct snd_card * card,struct snd_ctl_elem_value * control)848 static int snd_ctl_elem_read(struct snd_card *card,
849 struct snd_ctl_elem_value *control)
850 {
851 struct snd_kcontrol *kctl;
852 struct snd_kcontrol_volatile *vd;
853 unsigned int index_offset;
854
855 kctl = snd_ctl_find_id(card, &control->id);
856 if (kctl == NULL)
857 return -ENOENT;
858
859 index_offset = snd_ctl_get_ioff(kctl, &control->id);
860 vd = &kctl->vd[index_offset];
861 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) || kctl->get == NULL)
862 return -EPERM;
863
864 snd_ctl_build_ioff(&control->id, kctl, index_offset);
865 return kctl->get(kctl, control);
866 }
867
snd_ctl_elem_read_user(struct snd_card * card,struct snd_ctl_elem_value __user * _control)868 static int snd_ctl_elem_read_user(struct snd_card *card,
869 struct snd_ctl_elem_value __user *_control)
870 {
871 struct snd_ctl_elem_value *control;
872 int result;
873
874 control = memdup_user(_control, sizeof(*control));
875 if (IS_ERR(control))
876 return PTR_ERR(control);
877
878 result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
879 if (result < 0)
880 goto error;
881
882 down_read(&card->controls_rwsem);
883 result = snd_ctl_elem_read(card, control);
884 up_read(&card->controls_rwsem);
885 if (result < 0)
886 goto error;
887
888 if (copy_to_user(_control, control, sizeof(*control)))
889 result = -EFAULT;
890 error:
891 kfree(control);
892 return result;
893 }
894
snd_ctl_elem_write(struct snd_card * card,struct snd_ctl_file * file,struct snd_ctl_elem_value * control)895 static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
896 struct snd_ctl_elem_value *control)
897 {
898 struct snd_kcontrol *kctl;
899 struct snd_kcontrol_volatile *vd;
900 unsigned int index_offset;
901 int result;
902
903 kctl = snd_ctl_find_id(card, &control->id);
904 if (kctl == NULL)
905 return -ENOENT;
906
907 index_offset = snd_ctl_get_ioff(kctl, &control->id);
908 vd = &kctl->vd[index_offset];
909 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||
910 (file && vd->owner && vd->owner != file)) {
911 return -EPERM;
912 }
913
914 snd_ctl_build_ioff(&control->id, kctl, index_offset);
915 result = kctl->put(kctl, control);
916 if (result < 0)
917 return result;
918
919 if (result > 0) {
920 struct snd_ctl_elem_id id = control->id;
921 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &id);
922 }
923
924 return 0;
925 }
926
snd_ctl_elem_write_user(struct snd_ctl_file * file,struct snd_ctl_elem_value __user * _control)927 static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
928 struct snd_ctl_elem_value __user *_control)
929 {
930 struct snd_ctl_elem_value *control;
931 struct snd_card *card;
932 int result;
933
934 control = memdup_user(_control, sizeof(*control));
935 if (IS_ERR(control))
936 return PTR_ERR(control);
937
938 card = file->card;
939 result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
940 if (result < 0)
941 goto error;
942
943 down_write(&card->controls_rwsem);
944 result = snd_ctl_elem_write(card, file, control);
945 up_write(&card->controls_rwsem);
946 if (result < 0)
947 goto error;
948
949 if (copy_to_user(_control, control, sizeof(*control)))
950 result = -EFAULT;
951 error:
952 kfree(control);
953 return result;
954 }
955
snd_ctl_elem_lock(struct snd_ctl_file * file,struct snd_ctl_elem_id __user * _id)956 static int snd_ctl_elem_lock(struct snd_ctl_file *file,
957 struct snd_ctl_elem_id __user *_id)
958 {
959 struct snd_card *card = file->card;
960 struct snd_ctl_elem_id id;
961 struct snd_kcontrol *kctl;
962 struct snd_kcontrol_volatile *vd;
963 int result;
964
965 if (copy_from_user(&id, _id, sizeof(id)))
966 return -EFAULT;
967 down_write(&card->controls_rwsem);
968 kctl = snd_ctl_find_id(card, &id);
969 if (kctl == NULL) {
970 result = -ENOENT;
971 } else {
972 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
973 if (vd->owner != NULL)
974 result = -EBUSY;
975 else {
976 vd->owner = file;
977 result = 0;
978 }
979 }
980 up_write(&card->controls_rwsem);
981 return result;
982 }
983
snd_ctl_elem_unlock(struct snd_ctl_file * file,struct snd_ctl_elem_id __user * _id)984 static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
985 struct snd_ctl_elem_id __user *_id)
986 {
987 struct snd_card *card = file->card;
988 struct snd_ctl_elem_id id;
989 struct snd_kcontrol *kctl;
990 struct snd_kcontrol_volatile *vd;
991 int result;
992
993 if (copy_from_user(&id, _id, sizeof(id)))
994 return -EFAULT;
995 down_write(&card->controls_rwsem);
996 kctl = snd_ctl_find_id(card, &id);
997 if (kctl == NULL) {
998 result = -ENOENT;
999 } else {
1000 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1001 if (vd->owner == NULL)
1002 result = -EINVAL;
1003 else if (vd->owner != file)
1004 result = -EPERM;
1005 else {
1006 vd->owner = NULL;
1007 result = 0;
1008 }
1009 }
1010 up_write(&card->controls_rwsem);
1011 return result;
1012 }
1013
1014 struct user_element {
1015 struct snd_ctl_elem_info info;
1016 struct snd_card *card;
1017 char *elem_data; /* element data */
1018 unsigned long elem_data_size; /* size of element data in bytes */
1019 void *tlv_data; /* TLV data */
1020 unsigned long tlv_data_size; /* TLV data size */
1021 void *priv_data; /* private data (like strings for enumerated type) */
1022 };
1023
snd_ctl_elem_user_info(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_info * uinfo)1024 static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1025 struct snd_ctl_elem_info *uinfo)
1026 {
1027 struct user_element *ue = kcontrol->private_data;
1028 unsigned int offset;
1029
1030 offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1031 *uinfo = ue->info;
1032 snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1033
1034 return 0;
1035 }
1036
snd_ctl_elem_user_enum_info(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_info * uinfo)1037 static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1038 struct snd_ctl_elem_info *uinfo)
1039 {
1040 struct user_element *ue = kcontrol->private_data;
1041 const char *names;
1042 unsigned int item;
1043 unsigned int offset;
1044
1045 item = uinfo->value.enumerated.item;
1046
1047 offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1048 *uinfo = ue->info;
1049 snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1050
1051 item = min(item, uinfo->value.enumerated.items - 1);
1052 uinfo->value.enumerated.item = item;
1053
1054 names = ue->priv_data;
1055 for (; item > 0; --item)
1056 names += strlen(names) + 1;
1057 strcpy(uinfo->value.enumerated.name, names);
1058
1059 return 0;
1060 }
1061
snd_ctl_elem_user_get(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)1062 static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1063 struct snd_ctl_elem_value *ucontrol)
1064 {
1065 struct user_element *ue = kcontrol->private_data;
1066 unsigned int size = ue->elem_data_size;
1067 char *src = ue->elem_data +
1068 snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1069
1070 memcpy(&ucontrol->value, src, size);
1071 return 0;
1072 }
1073
snd_ctl_elem_user_put(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_value * ucontrol)1074 static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1075 struct snd_ctl_elem_value *ucontrol)
1076 {
1077 int change;
1078 struct user_element *ue = kcontrol->private_data;
1079 unsigned int size = ue->elem_data_size;
1080 char *dst = ue->elem_data +
1081 snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1082
1083 change = memcmp(&ucontrol->value, dst, size) != 0;
1084 if (change)
1085 memcpy(dst, &ucontrol->value, size);
1086 return change;
1087 }
1088
replace_user_tlv(struct snd_kcontrol * kctl,unsigned int __user * buf,unsigned int size)1089 static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1090 unsigned int size)
1091 {
1092 struct user_element *ue = kctl->private_data;
1093 unsigned int *container;
1094 struct snd_ctl_elem_id id;
1095 unsigned int mask = 0;
1096 int i;
1097 int change;
1098
1099 if (size > 1024 * 128) /* sane value */
1100 return -EINVAL;
1101
1102 container = vmemdup_user(buf, size);
1103 if (IS_ERR(container))
1104 return PTR_ERR(container);
1105
1106 change = ue->tlv_data_size != size;
1107 if (!change)
1108 change = memcmp(ue->tlv_data, container, size) != 0;
1109 if (!change) {
1110 kvfree(container);
1111 return 0;
1112 }
1113
1114 if (ue->tlv_data == NULL) {
1115 /* Now TLV data is available. */
1116 for (i = 0; i < kctl->count; ++i)
1117 kctl->vd[i].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
1118 mask = SNDRV_CTL_EVENT_MASK_INFO;
1119 }
1120
1121 kvfree(ue->tlv_data);
1122 ue->tlv_data = container;
1123 ue->tlv_data_size = size;
1124
1125 mask |= SNDRV_CTL_EVENT_MASK_TLV;
1126 for (i = 0; i < kctl->count; ++i) {
1127 snd_ctl_build_ioff(&id, kctl, i);
1128 snd_ctl_notify(ue->card, mask, &id);
1129 }
1130
1131 return change;
1132 }
1133
read_user_tlv(struct snd_kcontrol * kctl,unsigned int __user * buf,unsigned int size)1134 static int read_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
1135 unsigned int size)
1136 {
1137 struct user_element *ue = kctl->private_data;
1138
1139 if (ue->tlv_data_size == 0 || ue->tlv_data == NULL)
1140 return -ENXIO;
1141
1142 if (size < ue->tlv_data_size)
1143 return -ENOSPC;
1144
1145 if (copy_to_user(buf, ue->tlv_data, ue->tlv_data_size))
1146 return -EFAULT;
1147
1148 return 0;
1149 }
1150
snd_ctl_elem_user_tlv(struct snd_kcontrol * kctl,int op_flag,unsigned int size,unsigned int __user * buf)1151 static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kctl, int op_flag,
1152 unsigned int size, unsigned int __user *buf)
1153 {
1154 if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
1155 return replace_user_tlv(kctl, buf, size);
1156 else
1157 return read_user_tlv(kctl, buf, size);
1158 }
1159
snd_ctl_elem_init_enum_names(struct user_element * ue)1160 static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1161 {
1162 char *names, *p;
1163 size_t buf_len, name_len;
1164 unsigned int i;
1165 const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1166
1167 if (ue->info.value.enumerated.names_length > 64 * 1024)
1168 return -EINVAL;
1169
1170 names = vmemdup_user((const void __user *)user_ptrval,
1171 ue->info.value.enumerated.names_length);
1172 if (IS_ERR(names))
1173 return PTR_ERR(names);
1174
1175 /* check that there are enough valid names */
1176 buf_len = ue->info.value.enumerated.names_length;
1177 p = names;
1178 for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1179 name_len = strnlen(p, buf_len);
1180 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1181 kvfree(names);
1182 return -EINVAL;
1183 }
1184 p += name_len + 1;
1185 buf_len -= name_len + 1;
1186 }
1187
1188 ue->priv_data = names;
1189 ue->info.value.enumerated.names_ptr = 0;
1190
1191 return 0;
1192 }
1193
snd_ctl_elem_user_free(struct snd_kcontrol * kcontrol)1194 static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1195 {
1196 struct user_element *ue = kcontrol->private_data;
1197
1198 kvfree(ue->tlv_data);
1199 kvfree(ue->priv_data);
1200 kfree(ue);
1201 }
1202
snd_ctl_elem_add(struct snd_ctl_file * file,struct snd_ctl_elem_info * info,int replace)1203 static int snd_ctl_elem_add(struct snd_ctl_file *file,
1204 struct snd_ctl_elem_info *info, int replace)
1205 {
1206 /* The capacity of struct snd_ctl_elem_value.value.*/
1207 static const unsigned int value_sizes[] = {
1208 [SNDRV_CTL_ELEM_TYPE_BOOLEAN] = sizeof(long),
1209 [SNDRV_CTL_ELEM_TYPE_INTEGER] = sizeof(long),
1210 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
1211 [SNDRV_CTL_ELEM_TYPE_BYTES] = sizeof(unsigned char),
1212 [SNDRV_CTL_ELEM_TYPE_IEC958] = sizeof(struct snd_aes_iec958),
1213 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
1214 };
1215 static const unsigned int max_value_counts[] = {
1216 [SNDRV_CTL_ELEM_TYPE_BOOLEAN] = 128,
1217 [SNDRV_CTL_ELEM_TYPE_INTEGER] = 128,
1218 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
1219 [SNDRV_CTL_ELEM_TYPE_BYTES] = 512,
1220 [SNDRV_CTL_ELEM_TYPE_IEC958] = 1,
1221 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
1222 };
1223 struct snd_card *card = file->card;
1224 struct snd_kcontrol *kctl;
1225 unsigned int count;
1226 unsigned int access;
1227 long private_size;
1228 struct user_element *ue;
1229 unsigned int offset;
1230 int err;
1231
1232 if (!*info->id.name)
1233 return -EINVAL;
1234 if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1235 return -EINVAL;
1236
1237 /* Delete a control to replace them if needed. */
1238 if (replace) {
1239 info->id.numid = 0;
1240 err = snd_ctl_remove_user_ctl(file, &info->id);
1241 if (err)
1242 return err;
1243 }
1244
1245 /*
1246 * The number of userspace controls are counted control by control,
1247 * not element by element.
1248 */
1249 if (card->user_ctl_count + 1 > MAX_USER_CONTROLS)
1250 return -ENOMEM;
1251
1252 /* Check the number of elements for this userspace control. */
1253 count = info->owner;
1254 if (count == 0)
1255 count = 1;
1256
1257 /* Arrange access permissions if needed. */
1258 access = info->access;
1259 if (access == 0)
1260 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
1261 access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
1262 SNDRV_CTL_ELEM_ACCESS_INACTIVE |
1263 SNDRV_CTL_ELEM_ACCESS_TLV_WRITE);
1264
1265 /* In initial state, nothing is available as TLV container. */
1266 if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1267 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1268 access |= SNDRV_CTL_ELEM_ACCESS_USER;
1269
1270 /*
1271 * Check information and calculate the size of data specific to
1272 * this userspace control.
1273 */
1274 if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
1275 info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64)
1276 return -EINVAL;
1277 if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
1278 info->value.enumerated.items == 0)
1279 return -EINVAL;
1280 if (info->count < 1 ||
1281 info->count > max_value_counts[info->type])
1282 return -EINVAL;
1283 if (!validate_element_member_dimension(info))
1284 return -EINVAL;
1285 private_size = value_sizes[info->type] * info->count;
1286
1287 /*
1288 * Keep memory object for this userspace control. After passing this
1289 * code block, the instance should be freed by snd_ctl_free_one().
1290 *
1291 * Note that these elements in this control are locked.
1292 */
1293 err = snd_ctl_new(&kctl, count, access, file);
1294 if (err < 0)
1295 return err;
1296 memcpy(&kctl->id, &info->id, sizeof(kctl->id));
1297 kctl->private_data = kzalloc(sizeof(struct user_element) + private_size * count,
1298 GFP_KERNEL);
1299 if (kctl->private_data == NULL) {
1300 kfree(kctl);
1301 return -ENOMEM;
1302 }
1303 kctl->private_free = snd_ctl_elem_user_free;
1304
1305 /* Set private data for this userspace control. */
1306 ue = (struct user_element *)kctl->private_data;
1307 ue->card = card;
1308 ue->info = *info;
1309 ue->info.access = 0;
1310 ue->elem_data = (char *)ue + sizeof(*ue);
1311 ue->elem_data_size = private_size;
1312 if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1313 err = snd_ctl_elem_init_enum_names(ue);
1314 if (err < 0) {
1315 snd_ctl_free_one(kctl);
1316 return err;
1317 }
1318 }
1319
1320 /* Set callback functions. */
1321 if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1322 kctl->info = snd_ctl_elem_user_enum_info;
1323 else
1324 kctl->info = snd_ctl_elem_user_info;
1325 if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1326 kctl->get = snd_ctl_elem_user_get;
1327 if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1328 kctl->put = snd_ctl_elem_user_put;
1329 if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
1330 kctl->tlv.c = snd_ctl_elem_user_tlv;
1331
1332 /* This function manage to free the instance on failure. */
1333 down_write(&card->controls_rwsem);
1334 err = __snd_ctl_add_replace(card, kctl, CTL_ADD_EXCLUSIVE);
1335 if (err < 0) {
1336 snd_ctl_free_one(kctl);
1337 goto unlock;
1338 }
1339 offset = snd_ctl_get_ioff(kctl, &info->id);
1340 snd_ctl_build_ioff(&info->id, kctl, offset);
1341 /*
1342 * Here we cannot fill any field for the number of elements added by
1343 * this operation because there're no specific fields. The usage of
1344 * 'owner' field for this purpose may cause any bugs to userspace
1345 * applications because the field originally means PID of a process
1346 * which locks the element.
1347 */
1348
1349 card->user_ctl_count++;
1350
1351 unlock:
1352 up_write(&card->controls_rwsem);
1353 return err;
1354 }
1355
snd_ctl_elem_add_user(struct snd_ctl_file * file,struct snd_ctl_elem_info __user * _info,int replace)1356 static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1357 struct snd_ctl_elem_info __user *_info, int replace)
1358 {
1359 struct snd_ctl_elem_info info;
1360 int err;
1361
1362 if (copy_from_user(&info, _info, sizeof(info)))
1363 return -EFAULT;
1364 err = snd_ctl_elem_add(file, &info, replace);
1365 if (err < 0)
1366 return err;
1367 if (copy_to_user(_info, &info, sizeof(info))) {
1368 snd_ctl_remove_user_ctl(file, &info.id);
1369 return -EFAULT;
1370 }
1371
1372 return 0;
1373 }
1374
snd_ctl_elem_remove(struct snd_ctl_file * file,struct snd_ctl_elem_id __user * _id)1375 static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1376 struct snd_ctl_elem_id __user *_id)
1377 {
1378 struct snd_ctl_elem_id id;
1379
1380 if (copy_from_user(&id, _id, sizeof(id)))
1381 return -EFAULT;
1382 return snd_ctl_remove_user_ctl(file, &id);
1383 }
1384
snd_ctl_subscribe_events(struct snd_ctl_file * file,int __user * ptr)1385 static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1386 {
1387 int subscribe;
1388 if (get_user(subscribe, ptr))
1389 return -EFAULT;
1390 if (subscribe < 0) {
1391 subscribe = file->subscribed;
1392 if (put_user(subscribe, ptr))
1393 return -EFAULT;
1394 return 0;
1395 }
1396 if (subscribe) {
1397 file->subscribed = 1;
1398 return 0;
1399 } else if (file->subscribed) {
1400 snd_ctl_empty_read_queue(file);
1401 file->subscribed = 0;
1402 }
1403 return 0;
1404 }
1405
call_tlv_handler(struct snd_ctl_file * file,int op_flag,struct snd_kcontrol * kctl,struct snd_ctl_elem_id * id,unsigned int __user * buf,unsigned int size)1406 static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
1407 struct snd_kcontrol *kctl,
1408 struct snd_ctl_elem_id *id,
1409 unsigned int __user *buf, unsigned int size)
1410 {
1411 static const struct {
1412 int op;
1413 int perm;
1414 } pairs[] = {
1415 {SNDRV_CTL_TLV_OP_READ, SNDRV_CTL_ELEM_ACCESS_TLV_READ},
1416 {SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},
1417 {SNDRV_CTL_TLV_OP_CMD, SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},
1418 };
1419 struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1420 int i;
1421
1422 /* Check support of the request for this element. */
1423 for (i = 0; i < ARRAY_SIZE(pairs); ++i) {
1424 if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))
1425 break;
1426 }
1427 if (i == ARRAY_SIZE(pairs))
1428 return -ENXIO;
1429
1430 if (kctl->tlv.c == NULL)
1431 return -ENXIO;
1432
1433 /* Write and command operations are not allowed for locked element. */
1434 if (op_flag != SNDRV_CTL_TLV_OP_READ &&
1435 vd->owner != NULL && vd->owner != file)
1436 return -EPERM;
1437
1438 return kctl->tlv.c(kctl, op_flag, size, buf);
1439 }
1440
read_tlv_buf(struct snd_kcontrol * kctl,struct snd_ctl_elem_id * id,unsigned int __user * buf,unsigned int size)1441 static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,
1442 unsigned int __user *buf, unsigned int size)
1443 {
1444 struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
1445 unsigned int len;
1446
1447 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ))
1448 return -ENXIO;
1449
1450 if (kctl->tlv.p == NULL)
1451 return -ENXIO;
1452
1453 len = sizeof(unsigned int) * 2 + kctl->tlv.p[1];
1454 if (size < len)
1455 return -ENOMEM;
1456
1457 if (copy_to_user(buf, kctl->tlv.p, len))
1458 return -EFAULT;
1459
1460 return 0;
1461 }
1462
snd_ctl_tlv_ioctl(struct snd_ctl_file * file,struct snd_ctl_tlv __user * buf,int op_flag)1463 static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1464 struct snd_ctl_tlv __user *buf,
1465 int op_flag)
1466 {
1467 struct snd_ctl_tlv header;
1468 unsigned int __user *container;
1469 unsigned int container_size;
1470 struct snd_kcontrol *kctl;
1471 struct snd_ctl_elem_id id;
1472 struct snd_kcontrol_volatile *vd;
1473
1474 if (copy_from_user(&header, buf, sizeof(header)))
1475 return -EFAULT;
1476
1477 /* In design of control core, numerical ID starts at 1. */
1478 if (header.numid == 0)
1479 return -EINVAL;
1480
1481 /* At least, container should include type and length fields. */
1482 if (header.length < sizeof(unsigned int) * 2)
1483 return -EINVAL;
1484 container_size = header.length;
1485 container = buf->tlv;
1486
1487 kctl = snd_ctl_find_numid(file->card, header.numid);
1488 if (kctl == NULL)
1489 return -ENOENT;
1490
1491 /* Calculate index of the element in this set. */
1492 id = kctl->id;
1493 snd_ctl_build_ioff(&id, kctl, header.numid - id.numid);
1494 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1495
1496 if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1497 return call_tlv_handler(file, op_flag, kctl, &id, container,
1498 container_size);
1499 } else {
1500 if (op_flag == SNDRV_CTL_TLV_OP_READ) {
1501 return read_tlv_buf(kctl, &id, container,
1502 container_size);
1503 }
1504 }
1505
1506 /* Not supported. */
1507 return -ENXIO;
1508 }
1509
snd_ctl_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1510 static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1511 {
1512 struct snd_ctl_file *ctl;
1513 struct snd_card *card;
1514 struct snd_kctl_ioctl *p;
1515 void __user *argp = (void __user *)arg;
1516 int __user *ip = argp;
1517 int err;
1518
1519 ctl = file->private_data;
1520 card = ctl->card;
1521 if (snd_BUG_ON(!card))
1522 return -ENXIO;
1523 switch (cmd) {
1524 case SNDRV_CTL_IOCTL_PVERSION:
1525 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1526 case SNDRV_CTL_IOCTL_CARD_INFO:
1527 return snd_ctl_card_info(card, ctl, cmd, argp);
1528 case SNDRV_CTL_IOCTL_ELEM_LIST:
1529 return snd_ctl_elem_list(card, argp);
1530 case SNDRV_CTL_IOCTL_ELEM_INFO:
1531 return snd_ctl_elem_info_user(ctl, argp);
1532 case SNDRV_CTL_IOCTL_ELEM_READ:
1533 return snd_ctl_elem_read_user(card, argp);
1534 case SNDRV_CTL_IOCTL_ELEM_WRITE:
1535 return snd_ctl_elem_write_user(ctl, argp);
1536 case SNDRV_CTL_IOCTL_ELEM_LOCK:
1537 return snd_ctl_elem_lock(ctl, argp);
1538 case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1539 return snd_ctl_elem_unlock(ctl, argp);
1540 case SNDRV_CTL_IOCTL_ELEM_ADD:
1541 return snd_ctl_elem_add_user(ctl, argp, 0);
1542 case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1543 return snd_ctl_elem_add_user(ctl, argp, 1);
1544 case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1545 return snd_ctl_elem_remove(ctl, argp);
1546 case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1547 return snd_ctl_subscribe_events(ctl, ip);
1548 case SNDRV_CTL_IOCTL_TLV_READ:
1549 down_read(&ctl->card->controls_rwsem);
1550 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
1551 up_read(&ctl->card->controls_rwsem);
1552 return err;
1553 case SNDRV_CTL_IOCTL_TLV_WRITE:
1554 down_write(&ctl->card->controls_rwsem);
1555 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
1556 up_write(&ctl->card->controls_rwsem);
1557 return err;
1558 case SNDRV_CTL_IOCTL_TLV_COMMAND:
1559 down_write(&ctl->card->controls_rwsem);
1560 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
1561 up_write(&ctl->card->controls_rwsem);
1562 return err;
1563 case SNDRV_CTL_IOCTL_POWER:
1564 return -ENOPROTOOPT;
1565 case SNDRV_CTL_IOCTL_POWER_STATE:
1566 #ifdef CONFIG_PM
1567 return put_user(card->power_state, ip) ? -EFAULT : 0;
1568 #else
1569 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1570 #endif
1571 }
1572 down_read(&snd_ioctl_rwsem);
1573 list_for_each_entry(p, &snd_control_ioctls, list) {
1574 err = p->fioctl(card, ctl, cmd, arg);
1575 if (err != -ENOIOCTLCMD) {
1576 up_read(&snd_ioctl_rwsem);
1577 return err;
1578 }
1579 }
1580 up_read(&snd_ioctl_rwsem);
1581 dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
1582 return -ENOTTY;
1583 }
1584
snd_ctl_read(struct file * file,char __user * buffer,size_t count,loff_t * offset)1585 static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1586 size_t count, loff_t * offset)
1587 {
1588 struct snd_ctl_file *ctl;
1589 int err = 0;
1590 ssize_t result = 0;
1591
1592 ctl = file->private_data;
1593 if (snd_BUG_ON(!ctl || !ctl->card))
1594 return -ENXIO;
1595 if (!ctl->subscribed)
1596 return -EBADFD;
1597 if (count < sizeof(struct snd_ctl_event))
1598 return -EINVAL;
1599 spin_lock_irq(&ctl->read_lock);
1600 while (count >= sizeof(struct snd_ctl_event)) {
1601 struct snd_ctl_event ev;
1602 struct snd_kctl_event *kev;
1603 while (list_empty(&ctl->events)) {
1604 wait_queue_entry_t wait;
1605 if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1606 err = -EAGAIN;
1607 goto __end_lock;
1608 }
1609 init_waitqueue_entry(&wait, current);
1610 add_wait_queue(&ctl->change_sleep, &wait);
1611 set_current_state(TASK_INTERRUPTIBLE);
1612 spin_unlock_irq(&ctl->read_lock);
1613 schedule();
1614 remove_wait_queue(&ctl->change_sleep, &wait);
1615 if (ctl->card->shutdown)
1616 return -ENODEV;
1617 if (signal_pending(current))
1618 return -ERESTARTSYS;
1619 spin_lock_irq(&ctl->read_lock);
1620 }
1621 kev = snd_kctl_event(ctl->events.next);
1622 ev.type = SNDRV_CTL_EVENT_ELEM;
1623 ev.data.elem.mask = kev->mask;
1624 ev.data.elem.id = kev->id;
1625 list_del(&kev->list);
1626 spin_unlock_irq(&ctl->read_lock);
1627 kfree(kev);
1628 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1629 err = -EFAULT;
1630 goto __end;
1631 }
1632 spin_lock_irq(&ctl->read_lock);
1633 buffer += sizeof(struct snd_ctl_event);
1634 count -= sizeof(struct snd_ctl_event);
1635 result += sizeof(struct snd_ctl_event);
1636 }
1637 __end_lock:
1638 spin_unlock_irq(&ctl->read_lock);
1639 __end:
1640 return result > 0 ? result : err;
1641 }
1642
snd_ctl_poll(struct file * file,poll_table * wait)1643 static __poll_t snd_ctl_poll(struct file *file, poll_table * wait)
1644 {
1645 __poll_t mask;
1646 struct snd_ctl_file *ctl;
1647
1648 ctl = file->private_data;
1649 if (!ctl->subscribed)
1650 return 0;
1651 poll_wait(file, &ctl->change_sleep, wait);
1652
1653 mask = 0;
1654 if (!list_empty(&ctl->events))
1655 mask |= EPOLLIN | EPOLLRDNORM;
1656
1657 return mask;
1658 }
1659
1660 /*
1661 * register the device-specific control-ioctls.
1662 * called from each device manager like pcm.c, hwdep.c, etc.
1663 */
_snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn,struct list_head * lists)1664 static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1665 {
1666 struct snd_kctl_ioctl *pn;
1667
1668 pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1669 if (pn == NULL)
1670 return -ENOMEM;
1671 pn->fioctl = fcn;
1672 down_write(&snd_ioctl_rwsem);
1673 list_add_tail(&pn->list, lists);
1674 up_write(&snd_ioctl_rwsem);
1675 return 0;
1676 }
1677
1678 /**
1679 * snd_ctl_register_ioctl - register the device-specific control-ioctls
1680 * @fcn: ioctl callback function
1681 *
1682 * called from each device manager like pcm.c, hwdep.c, etc.
1683 */
snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)1684 int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1685 {
1686 return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1687 }
1688 EXPORT_SYMBOL(snd_ctl_register_ioctl);
1689
1690 #ifdef CONFIG_COMPAT
1691 /**
1692 * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
1693 * control-ioctls
1694 * @fcn: ioctl callback function
1695 */
snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)1696 int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1697 {
1698 return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1699 }
1700 EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1701 #endif
1702
1703 /*
1704 * de-register the device-specific control-ioctls.
1705 */
_snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,struct list_head * lists)1706 static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1707 struct list_head *lists)
1708 {
1709 struct snd_kctl_ioctl *p;
1710
1711 if (snd_BUG_ON(!fcn))
1712 return -EINVAL;
1713 down_write(&snd_ioctl_rwsem);
1714 list_for_each_entry(p, lists, list) {
1715 if (p->fioctl == fcn) {
1716 list_del(&p->list);
1717 up_write(&snd_ioctl_rwsem);
1718 kfree(p);
1719 return 0;
1720 }
1721 }
1722 up_write(&snd_ioctl_rwsem);
1723 snd_BUG();
1724 return -EINVAL;
1725 }
1726
1727 /**
1728 * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
1729 * @fcn: ioctl callback function to unregister
1730 */
snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)1731 int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1732 {
1733 return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1734 }
1735 EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1736
1737 #ifdef CONFIG_COMPAT
1738 /**
1739 * snd_ctl_unregister_ioctl - de-register the device-specific compat 32bit
1740 * control-ioctls
1741 * @fcn: ioctl callback function to unregister
1742 */
snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)1743 int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1744 {
1745 return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1746 }
1747 EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1748 #endif
1749
snd_ctl_fasync(int fd,struct file * file,int on)1750 static int snd_ctl_fasync(int fd, struct file * file, int on)
1751 {
1752 struct snd_ctl_file *ctl;
1753
1754 ctl = file->private_data;
1755 return fasync_helper(fd, file, on, &ctl->fasync);
1756 }
1757
1758 /* return the preferred subdevice number if already assigned;
1759 * otherwise return -1
1760 */
snd_ctl_get_preferred_subdevice(struct snd_card * card,int type)1761 int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
1762 {
1763 struct snd_ctl_file *kctl;
1764 int subdevice = -1;
1765
1766 read_lock(&card->ctl_files_rwlock);
1767 list_for_each_entry(kctl, &card->ctl_files, list) {
1768 if (kctl->pid == task_pid(current)) {
1769 subdevice = kctl->preferred_subdevice[type];
1770 if (subdevice != -1)
1771 break;
1772 }
1773 }
1774 read_unlock(&card->ctl_files_rwlock);
1775 return subdevice;
1776 }
1777 EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
1778
1779 /*
1780 * ioctl32 compat
1781 */
1782 #ifdef CONFIG_COMPAT
1783 #include "control_compat.c"
1784 #else
1785 #define snd_ctl_ioctl_compat NULL
1786 #endif
1787
1788 /*
1789 * INIT PART
1790 */
1791
1792 static const struct file_operations snd_ctl_f_ops =
1793 {
1794 .owner = THIS_MODULE,
1795 .read = snd_ctl_read,
1796 .open = snd_ctl_open,
1797 .release = snd_ctl_release,
1798 .llseek = no_llseek,
1799 .poll = snd_ctl_poll,
1800 .unlocked_ioctl = snd_ctl_ioctl,
1801 .compat_ioctl = snd_ctl_ioctl_compat,
1802 .fasync = snd_ctl_fasync,
1803 };
1804
1805 /*
1806 * registration of the control device
1807 */
snd_ctl_dev_register(struct snd_device * device)1808 static int snd_ctl_dev_register(struct snd_device *device)
1809 {
1810 struct snd_card *card = device->device_data;
1811
1812 return snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1813 &snd_ctl_f_ops, card, &card->ctl_dev);
1814 }
1815
1816 /*
1817 * disconnection of the control device
1818 */
snd_ctl_dev_disconnect(struct snd_device * device)1819 static int snd_ctl_dev_disconnect(struct snd_device *device)
1820 {
1821 struct snd_card *card = device->device_data;
1822 struct snd_ctl_file *ctl;
1823
1824 read_lock(&card->ctl_files_rwlock);
1825 list_for_each_entry(ctl, &card->ctl_files, list) {
1826 wake_up(&ctl->change_sleep);
1827 kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1828 }
1829 read_unlock(&card->ctl_files_rwlock);
1830
1831 return snd_unregister_device(&card->ctl_dev);
1832 }
1833
1834 /*
1835 * free all controls
1836 */
snd_ctl_dev_free(struct snd_device * device)1837 static int snd_ctl_dev_free(struct snd_device *device)
1838 {
1839 struct snd_card *card = device->device_data;
1840 struct snd_kcontrol *control;
1841
1842 down_write(&card->controls_rwsem);
1843 while (!list_empty(&card->controls)) {
1844 control = snd_kcontrol(card->controls.next);
1845 snd_ctl_remove(card, control);
1846 }
1847 up_write(&card->controls_rwsem);
1848 put_device(&card->ctl_dev);
1849 return 0;
1850 }
1851
1852 /*
1853 * create control core:
1854 * called from init.c
1855 */
snd_ctl_create(struct snd_card * card)1856 int snd_ctl_create(struct snd_card *card)
1857 {
1858 static struct snd_device_ops ops = {
1859 .dev_free = snd_ctl_dev_free,
1860 .dev_register = snd_ctl_dev_register,
1861 .dev_disconnect = snd_ctl_dev_disconnect,
1862 };
1863 int err;
1864
1865 if (snd_BUG_ON(!card))
1866 return -ENXIO;
1867 if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
1868 return -ENXIO;
1869
1870 snd_device_initialize(&card->ctl_dev, card);
1871 dev_set_name(&card->ctl_dev, "controlC%d", card->number);
1872
1873 err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1874 if (err < 0)
1875 put_device(&card->ctl_dev);
1876 return err;
1877 }
1878
1879 /*
1880 * Frequently used control callbacks/helpers
1881 */
1882
1883 /**
1884 * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
1885 * callback with a mono channel
1886 * @kcontrol: the kcontrol instance
1887 * @uinfo: info to store
1888 *
1889 * This is a function that can be used as info callback for a standard
1890 * boolean control with a single mono channel.
1891 */
snd_ctl_boolean_mono_info(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_info * uinfo)1892 int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
1893 struct snd_ctl_elem_info *uinfo)
1894 {
1895 uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1896 uinfo->count = 1;
1897 uinfo->value.integer.min = 0;
1898 uinfo->value.integer.max = 1;
1899 return 0;
1900 }
1901 EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
1902
1903 /**
1904 * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
1905 * callback with stereo two channels
1906 * @kcontrol: the kcontrol instance
1907 * @uinfo: info to store
1908 *
1909 * This is a function that can be used as info callback for a standard
1910 * boolean control with stereo two channels.
1911 */
snd_ctl_boolean_stereo_info(struct snd_kcontrol * kcontrol,struct snd_ctl_elem_info * uinfo)1912 int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
1913 struct snd_ctl_elem_info *uinfo)
1914 {
1915 uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1916 uinfo->count = 2;
1917 uinfo->value.integer.min = 0;
1918 uinfo->value.integer.max = 1;
1919 return 0;
1920 }
1921 EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
1922
1923 /**
1924 * snd_ctl_enum_info - fills the info structure for an enumerated control
1925 * @info: the structure to be filled
1926 * @channels: the number of the control's channels; often one
1927 * @items: the number of control values; also the size of @names
1928 * @names: an array containing the names of all control values
1929 *
1930 * Sets all required fields in @info to their appropriate values.
1931 * If the control's accessibility is not the default (readable and writable),
1932 * the caller has to fill @info->access.
1933 *
1934 * Return: Zero.
1935 */
snd_ctl_enum_info(struct snd_ctl_elem_info * info,unsigned int channels,unsigned int items,const char * const names[])1936 int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
1937 unsigned int items, const char *const names[])
1938 {
1939 info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
1940 info->count = channels;
1941 info->value.enumerated.items = items;
1942 if (!items)
1943 return 0;
1944 if (info->value.enumerated.item >= items)
1945 info->value.enumerated.item = items - 1;
1946 WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
1947 "ALSA: too long item name '%s'\n",
1948 names[info->value.enumerated.item]);
1949 strlcpy(info->value.enumerated.name,
1950 names[info->value.enumerated.item],
1951 sizeof(info->value.enumerated.name));
1952 return 0;
1953 }
1954 EXPORT_SYMBOL(snd_ctl_enum_info);
1955