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