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