1/*
   2 *  Routines for driver control interface
   3 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   4 *
   5 *
   6 *   This program is free software; you can redistribute it and/or modify
   7 *   it under the terms of the GNU General Public License as published by
   8 *   the Free Software Foundation; either version 2 of the License, or
   9 *   (at your option) any later version.
  10 *
  11 *   This program is distributed in the hope that it will be useful,
  12 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 *   GNU General Public License for more details.
  15 *
  16 *   You should have received a copy of the GNU General Public License
  17 *   along with this program; if not, write to the Free Software
  18 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19 *
  20 */
  21
  22#include <linux/threads.h>
  23#include <linux/interrupt.h>
  24#include <linux/module.h>
  25#include <linux/slab.h>
  26#include <linux/vmalloc.h>
  27#include <linux/time.h>
 
 
  28#include <sound/core.h>
  29#include <sound/minors.h>
  30#include <sound/info.h>
  31#include <sound/control.h>
  32
  33/* max number of user-defined controls */
  34#define MAX_USER_CONTROLS	32
  35#define MAX_CONTROL_COUNT	1028
  36
  37struct snd_kctl_ioctl {
  38	struct list_head list;		/* list of all ioctls */
  39	snd_kctl_ioctl_func_t fioctl;
  40};
  41
  42static DECLARE_RWSEM(snd_ioctl_rwsem);
  43static LIST_HEAD(snd_control_ioctls);
  44#ifdef CONFIG_COMPAT
  45static LIST_HEAD(snd_control_compat_ioctls);
  46#endif
  47
  48static int snd_ctl_open(struct inode *inode, struct file *file)
  49{
  50	unsigned long flags;
  51	struct snd_card *card;
  52	struct snd_ctl_file *ctl;
  53	int i, err;
  54
  55	err = nonseekable_open(inode, file);
  56	if (err < 0)
  57		return err;
  58
  59	card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
  60	if (!card) {
  61		err = -ENODEV;
  62		goto __error1;
  63	}
  64	err = snd_card_file_add(card, file);
  65	if (err < 0) {
  66		err = -ENODEV;
  67		goto __error1;
  68	}
  69	if (!try_module_get(card->module)) {
  70		err = -EFAULT;
  71		goto __error2;
  72	}
  73	ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
  74	if (ctl == NULL) {
  75		err = -ENOMEM;
  76		goto __error;
  77	}
  78	INIT_LIST_HEAD(&ctl->events);
  79	init_waitqueue_head(&ctl->change_sleep);
  80	spin_lock_init(&ctl->read_lock);
  81	ctl->card = card;
  82	for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
  83		ctl->preferred_subdevice[i] = -1;
  84	ctl->pid = get_pid(task_pid(current));
  85	file->private_data = ctl;
  86	write_lock_irqsave(&card->ctl_files_rwlock, flags);
  87	list_add_tail(&ctl->list, &card->ctl_files);
  88	write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
  89	snd_card_unref(card);
  90	return 0;
  91
  92      __error:
  93	module_put(card->module);
  94      __error2:
  95	snd_card_file_remove(card, file);
  96      __error1:
  97	if (card)
  98		snd_card_unref(card);
  99      	return err;
 100}
 101
 102static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
 103{
 104	unsigned long flags;
 105	struct snd_kctl_event *cread;
 106	
 107	spin_lock_irqsave(&ctl->read_lock, flags);
 108	while (!list_empty(&ctl->events)) {
 109		cread = snd_kctl_event(ctl->events.next);
 110		list_del(&cread->list);
 111		kfree(cread);
 112	}
 113	spin_unlock_irqrestore(&ctl->read_lock, flags);
 114}
 115
 116static int snd_ctl_release(struct inode *inode, struct file *file)
 117{
 118	unsigned long flags;
 119	struct snd_card *card;
 120	struct snd_ctl_file *ctl;
 121	struct snd_kcontrol *control;
 122	unsigned int idx;
 123
 124	ctl = file->private_data;
 125	file->private_data = NULL;
 126	card = ctl->card;
 127	write_lock_irqsave(&card->ctl_files_rwlock, flags);
 128	list_del(&ctl->list);
 129	write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
 130	down_write(&card->controls_rwsem);
 131	list_for_each_entry(control, &card->controls, list)
 132		for (idx = 0; idx < control->count; idx++)
 133			if (control->vd[idx].owner == ctl)
 134				control->vd[idx].owner = NULL;
 135	up_write(&card->controls_rwsem);
 136	snd_ctl_empty_read_queue(ctl);
 137	put_pid(ctl->pid);
 138	kfree(ctl);
 139	module_put(card->module);
 140	snd_card_file_remove(card, file);
 141	return 0;
 142}
 143
 144/**
 145 * snd_ctl_notify - Send notification to user-space for a control change
 146 * @card: the card to send notification
 147 * @mask: the event mask, SNDRV_CTL_EVENT_*
 148 * @id: the ctl element id to send notification
 149 *
 150 * This function adds an event record with the given id and mask, appends
 151 * to the list and wakes up the user-space for notification.  This can be
 152 * called in the atomic context.
 153 */
 154void snd_ctl_notify(struct snd_card *card, unsigned int mask,
 155		    struct snd_ctl_elem_id *id)
 156{
 157	unsigned long flags;
 158	struct snd_ctl_file *ctl;
 159	struct snd_kctl_event *ev;
 160	
 161	if (snd_BUG_ON(!card || !id))
 162		return;
 163	if (card->shutdown)
 164		return;
 165	read_lock(&card->ctl_files_rwlock);
 166#if IS_ENABLED(CONFIG_SND_MIXER_OSS)
 167	card->mixer_oss_change_count++;
 168#endif
 169	list_for_each_entry(ctl, &card->ctl_files, list) {
 170		if (!ctl->subscribed)
 171			continue;
 172		spin_lock_irqsave(&ctl->read_lock, flags);
 173		list_for_each_entry(ev, &ctl->events, list) {
 174			if (ev->id.numid == id->numid) {
 175				ev->mask |= mask;
 176				goto _found;
 177			}
 178		}
 179		ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
 180		if (ev) {
 181			ev->id = *id;
 182			ev->mask = mask;
 183			list_add_tail(&ev->list, &ctl->events);
 184		} else {
 185			dev_err(card->dev, "No memory available to allocate event\n");
 186		}
 187	_found:
 188		wake_up(&ctl->change_sleep);
 189		spin_unlock_irqrestore(&ctl->read_lock, flags);
 190		kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
 191	}
 192	read_unlock(&card->ctl_files_rwlock);
 193}
 194EXPORT_SYMBOL(snd_ctl_notify);
 195
 196/**
 197 * snd_ctl_new - create a new control instance with some elements
 198 * @kctl: the pointer to store new control instance
 199 * @count: the number of elements in this control
 200 * @access: the default access flags for elements in this control
 201 * @file: given when locking these elements
 202 *
 203 * Allocates a memory object for a new control instance. The instance has
 204 * elements as many as the given number (@count). Each element has given
 205 * access permissions (@access). Each element is locked when @file is given.
 206 *
 207 * Return: 0 on success, error code on failure
 208 */
 209static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
 210		       unsigned int access, struct snd_ctl_file *file)
 211{
 212	unsigned int size;
 213	unsigned int idx;
 214	
 215	if (count == 0 || count > MAX_CONTROL_COUNT)
 216		return -EINVAL;
 217
 218	size  = sizeof(struct snd_kcontrol);
 219	size += sizeof(struct snd_kcontrol_volatile) * count;
 220
 221	*kctl = kzalloc(size, GFP_KERNEL);
 222	if (!*kctl)
 223		return -ENOMEM;
 224
 225	for (idx = 0; idx < count; idx++) {
 226		(*kctl)->vd[idx].access = access;
 227		(*kctl)->vd[idx].owner = file;
 228	}
 229	(*kctl)->count = count;
 230
 231	return 0;
 232}
 233
 234/**
 235 * snd_ctl_new1 - create a control instance from the template
 236 * @ncontrol: the initialization record
 237 * @private_data: the private data to set
 238 *
 239 * Allocates a new struct snd_kcontrol instance and initialize from the given 
 240 * template.  When the access field of ncontrol is 0, it's assumed as
 241 * READWRITE access. When the count field is 0, it's assumes as one.
 242 *
 243 * Return: The pointer of the newly generated instance, or %NULL on failure.
 244 */
 245struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
 246				  void *private_data)
 247{
 248	struct snd_kcontrol *kctl;
 249	unsigned int count;
 250	unsigned int access;
 251	int err;
 252	
 253	if (snd_BUG_ON(!ncontrol || !ncontrol->info))
 254		return NULL;
 255
 256	count = ncontrol->count;
 257	if (count == 0)
 258		count = 1;
 259
 260	access = ncontrol->access;
 261	if (access == 0)
 262		access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
 263	access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
 264		   SNDRV_CTL_ELEM_ACCESS_VOLATILE |
 265		   SNDRV_CTL_ELEM_ACCESS_INACTIVE |
 266		   SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
 267		   SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
 268		   SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK);
 269
 270	err = snd_ctl_new(&kctl, count, access, NULL);
 271	if (err < 0)
 272		return NULL;
 273
 274	/* The 'numid' member is decided when calling snd_ctl_add(). */
 275	kctl->id.iface = ncontrol->iface;
 276	kctl->id.device = ncontrol->device;
 277	kctl->id.subdevice = ncontrol->subdevice;
 278	if (ncontrol->name) {
 279		strlcpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
 280		if (strcmp(ncontrol->name, kctl->id.name) != 0)
 281			pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
 282				ncontrol->name, kctl->id.name);
 283	}
 284	kctl->id.index = ncontrol->index;
 285
 286	kctl->info = ncontrol->info;
 287	kctl->get = ncontrol->get;
 288	kctl->put = ncontrol->put;
 289	kctl->tlv.p = ncontrol->tlv.p;
 290
 291	kctl->private_value = ncontrol->private_value;
 292	kctl->private_data = private_data;
 293
 294	return kctl;
 295}
 296EXPORT_SYMBOL(snd_ctl_new1);
 297
 298/**
 299 * snd_ctl_free_one - release the control instance
 300 * @kcontrol: the control instance
 301 *
 302 * Releases the control instance created via snd_ctl_new()
 303 * or snd_ctl_new1().
 304 * Don't call this after the control was added to the card.
 305 */
 306void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
 307{
 308	if (kcontrol) {
 309		if (kcontrol->private_free)
 310			kcontrol->private_free(kcontrol);
 311		kfree(kcontrol);
 312	}
 313}
 314EXPORT_SYMBOL(snd_ctl_free_one);
 315
 316static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
 317					  unsigned int count)
 318{
 319	struct snd_kcontrol *kctl;
 320
 321	/* Make sure that the ids assigned to the control do not wrap around */
 322	if (card->last_numid >= UINT_MAX - count)
 323		card->last_numid = 0;
 324
 325	list_for_each_entry(kctl, &card->controls, list) {
 326		if (kctl->id.numid < card->last_numid + 1 + count &&
 327		    kctl->id.numid + kctl->count > card->last_numid + 1) {
 328		    	card->last_numid = kctl->id.numid + kctl->count - 1;
 329			return true;
 330		}
 331	}
 332	return false;
 333}
 334
 335static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
 336{
 337	unsigned int iter = 100000;
 338
 339	while (snd_ctl_remove_numid_conflict(card, count)) {
 340		if (--iter == 0) {
 341			/* this situation is very unlikely */
 342			dev_err(card->dev, "unable to allocate new control numid\n");
 343			return -ENOMEM;
 344		}
 345	}
 346	return 0;
 347}
 348
 349/**
 350 * snd_ctl_add - add the control instance to the card
 351 * @card: the card instance
 352 * @kcontrol: the control instance to add
 353 *
 354 * Adds the control instance created via snd_ctl_new() or
 355 * snd_ctl_new1() to the given card. Assigns also an unique
 356 * numid used for fast search.
 357 *
 358 * It frees automatically the control which cannot be added.
 359 *
 360 * Return: Zero if successful, or a negative error code on failure.
 361 *
 362 */
 363int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
 364{
 365	struct snd_ctl_elem_id id;
 366	unsigned int idx;
 367	unsigned int count;
 368	int err = -EINVAL;
 369
 370	if (! kcontrol)
 371		return err;
 372	if (snd_BUG_ON(!card || !kcontrol->info))
 373		goto error;
 374	id = kcontrol->id;
 375	if (id.index > UINT_MAX - kcontrol->count)
 376		goto error;
 377
 378	down_write(&card->controls_rwsem);
 379	if (snd_ctl_find_id(card, &id)) {
 380		up_write(&card->controls_rwsem);
 381		dev_err(card->dev, "control %i:%i:%i:%s:%i is already present\n",
 382					id.iface,
 383					id.device,
 384					id.subdevice,
 385					id.name,
 386					id.index);
 387		err = -EBUSY;
 388		goto error;
 389	}
 390	if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 391		up_write(&card->controls_rwsem);
 392		err = -ENOMEM;
 393		goto error;
 394	}
 395	list_add_tail(&kcontrol->list, &card->controls);
 396	card->controls_count += kcontrol->count;
 397	kcontrol->id.numid = card->last_numid + 1;
 398	card->last_numid += kcontrol->count;
 399	id = kcontrol->id;
 400	count = kcontrol->count;
 401	up_write(&card->controls_rwsem);
 402	for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 403		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 404	return 0;
 405
 406 error:
 407	snd_ctl_free_one(kcontrol);
 408	return err;
 409}
 410EXPORT_SYMBOL(snd_ctl_add);
 411
 412/**
 413 * snd_ctl_replace - replace the control instance of the card
 414 * @card: the card instance
 415 * @kcontrol: the control instance to replace
 416 * @add_on_replace: add the control if not already added
 417 *
 418 * Replaces the given control.  If the given control does not exist
 419 * and the add_on_replace flag is set, the control is added.  If the
 420 * control exists, it is destroyed first.
 421 *
 422 * It frees automatically the control which cannot be added or replaced.
 423 *
 424 * Return: Zero if successful, or a negative error code on failure.
 425 */
 426int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
 427		    bool add_on_replace)
 428{
 429	struct snd_ctl_elem_id id;
 430	unsigned int count;
 431	unsigned int idx;
 432	struct snd_kcontrol *old;
 433	int ret;
 434
 435	if (!kcontrol)
 436		return -EINVAL;
 437	if (snd_BUG_ON(!card || !kcontrol->info)) {
 438		ret = -EINVAL;
 439		goto error;
 440	}
 441	id = kcontrol->id;
 442	down_write(&card->controls_rwsem);
 443	old = snd_ctl_find_id(card, &id);
 444	if (!old) {
 445		if (add_on_replace)
 446			goto add;
 447		up_write(&card->controls_rwsem);
 448		ret = -EINVAL;
 449		goto error;
 450	}
 451	ret = snd_ctl_remove(card, old);
 452	if (ret < 0) {
 453		up_write(&card->controls_rwsem);
 454		goto error;
 455	}
 456add:
 457	if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
 458		up_write(&card->controls_rwsem);
 459		ret = -ENOMEM;
 460		goto error;
 461	}
 462	list_add_tail(&kcontrol->list, &card->controls);
 463	card->controls_count += kcontrol->count;
 464	kcontrol->id.numid = card->last_numid + 1;
 465	card->last_numid += kcontrol->count;
 466	id = kcontrol->id;
 467	count = kcontrol->count;
 468	up_write(&card->controls_rwsem);
 469	for (idx = 0; idx < count; idx++, id.index++, id.numid++)
 470		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
 471	return 0;
 472
 473error:
 474	snd_ctl_free_one(kcontrol);
 475	return ret;
 476}
 477EXPORT_SYMBOL(snd_ctl_replace);
 478
 479/**
 480 * snd_ctl_remove - remove the control from the card and release it
 481 * @card: the card instance
 482 * @kcontrol: the control instance to remove
 483 *
 484 * Removes the control from the card and then releases the instance.
 485 * You don't need to call snd_ctl_free_one(). You must be in
 486 * the write lock - down_write(&card->controls_rwsem).
 487 *
 488 * Return: 0 if successful, or a negative error code on failure.
 489 */
 490int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
 491{
 492	struct snd_ctl_elem_id id;
 493	unsigned int idx;
 494
 495	if (snd_BUG_ON(!card || !kcontrol))
 496		return -EINVAL;
 497	list_del(&kcontrol->list);
 498	card->controls_count -= kcontrol->count;
 499	id = kcontrol->id;
 500	for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
 501		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
 502	snd_ctl_free_one(kcontrol);
 503	return 0;
 504}
 505EXPORT_SYMBOL(snd_ctl_remove);
 506
 507/**
 508 * snd_ctl_remove_id - remove the control of the given id and release it
 509 * @card: the card instance
 510 * @id: the control id to remove
 511 *
 512 * Finds the control instance with the given id, removes it from the
 513 * card list and releases it.
 514 *
 515 * Return: 0 if successful, or a negative error code on failure.
 516 */
 517int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
 518{
 519	struct snd_kcontrol *kctl;
 520	int ret;
 521
 522	down_write(&card->controls_rwsem);
 523	kctl = snd_ctl_find_id(card, id);
 524	if (kctl == NULL) {
 525		up_write(&card->controls_rwsem);
 526		return -ENOENT;
 527	}
 528	ret = snd_ctl_remove(card, kctl);
 529	up_write(&card->controls_rwsem);
 530	return ret;
 531}
 532EXPORT_SYMBOL(snd_ctl_remove_id);
 533
 534/**
 535 * snd_ctl_remove_user_ctl - remove and release the unlocked user control
 536 * @file: active control handle
 537 * @id: the control id to remove
 538 *
 539 * Finds the control instance with the given id, removes it from the
 540 * card list and releases it.
 541 *
 542 * Return: 0 if successful, or a negative error code on failure.
 543 */
 544static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
 545				   struct snd_ctl_elem_id *id)
 546{
 547	struct snd_card *card = file->card;
 548	struct snd_kcontrol *kctl;
 549	int idx, ret;
 550
 551	down_write(&card->controls_rwsem);
 552	kctl = snd_ctl_find_id(card, id);
 553	if (kctl == NULL) {
 554		ret = -ENOENT;
 555		goto error;
 556	}
 557	if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER)) {
 558		ret = -EINVAL;
 559		goto error;
 560	}
 561	for (idx = 0; idx < kctl->count; idx++)
 562		if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
 563			ret = -EBUSY;
 564			goto error;
 565		}
 566	ret = snd_ctl_remove(card, kctl);
 567	if (ret < 0)
 568		goto error;
 569	card->user_ctl_count--;
 570error:
 571	up_write(&card->controls_rwsem);
 572	return ret;
 573}
 574
 575/**
 576 * snd_ctl_activate_id - activate/inactivate the control of the given id
 577 * @card: the card instance
 578 * @id: the control id to activate/inactivate
 579 * @active: non-zero to activate
 580 *
 581 * Finds the control instance with the given id, and activate or
 582 * inactivate the control together with notification, if changed.
 583 * The given ID data is filled with full information.
 584 *
 585 * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
 586 */
 587int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
 588			int active)
 589{
 590	struct snd_kcontrol *kctl;
 591	struct snd_kcontrol_volatile *vd;
 592	unsigned int index_offset;
 593	int ret;
 594
 595	down_write(&card->controls_rwsem);
 596	kctl = snd_ctl_find_id(card, id);
 597	if (kctl == NULL) {
 598		ret = -ENOENT;
 599		goto unlock;
 600	}
 601	index_offset = snd_ctl_get_ioff(kctl, id);
 602	vd = &kctl->vd[index_offset];
 603	ret = 0;
 604	if (active) {
 605		if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
 606			goto unlock;
 607		vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 608	} else {
 609		if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
 610			goto unlock;
 611		vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
 612	}
 613	snd_ctl_build_ioff(id, kctl, index_offset);
 614	ret = 1;
 615 unlock:
 616	up_write(&card->controls_rwsem);
 617	if (ret > 0)
 618		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_INFO, id);
 619	return ret;
 620}
 621EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
 622
 623/**
 624 * snd_ctl_rename_id - replace the id of a control on the card
 625 * @card: the card instance
 626 * @src_id: the old id
 627 * @dst_id: the new id
 628 *
 629 * Finds the control with the old id from the card, and replaces the
 630 * id with the new one.
 631 *
 632 * Return: Zero if successful, or a negative error code on failure.
 633 */
 634int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
 635		      struct snd_ctl_elem_id *dst_id)
 636{
 637	struct snd_kcontrol *kctl;
 638
 639	down_write(&card->controls_rwsem);
 640	kctl = snd_ctl_find_id(card, src_id);
 641	if (kctl == NULL) {
 642		up_write(&card->controls_rwsem);
 643		return -ENOENT;
 644	}
 645	kctl->id = *dst_id;
 646	kctl->id.numid = card->last_numid + 1;
 647	card->last_numid += kctl->count;
 648	up_write(&card->controls_rwsem);
 649	return 0;
 650}
 651EXPORT_SYMBOL(snd_ctl_rename_id);
 652
 653/**
 654 * snd_ctl_find_numid - find the control instance with the given number-id
 655 * @card: the card instance
 656 * @numid: the number-id to search
 657 *
 658 * Finds the control instance with the given number-id from the card.
 659 *
 660 * The caller must down card->controls_rwsem before calling this function
 661 * (if the race condition can happen).
 662 *
 663 * Return: The pointer of the instance if found, or %NULL if not.
 664 *
 665 */
 666struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card, unsigned int numid)
 667{
 668	struct snd_kcontrol *kctl;
 669
 670	if (snd_BUG_ON(!card || !numid))
 671		return NULL;
 672	list_for_each_entry(kctl, &card->controls, list) {
 673		if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
 674			return kctl;
 675	}
 676	return NULL;
 677}
 678EXPORT_SYMBOL(snd_ctl_find_numid);
 679
 680/**
 681 * snd_ctl_find_id - find the control instance with the given id
 682 * @card: the card instance
 683 * @id: the id to search
 684 *
 685 * Finds the control instance with the given id from the card.
 686 *
 687 * The caller must down card->controls_rwsem before calling this function
 688 * (if the race condition can happen).
 689 *
 690 * Return: The pointer of the instance if found, or %NULL if not.
 691 *
 692 */
 693struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
 694				     struct snd_ctl_elem_id *id)
 695{
 696	struct snd_kcontrol *kctl;
 697
 698	if (snd_BUG_ON(!card || !id))
 699		return NULL;
 700	if (id->numid != 0)
 701		return snd_ctl_find_numid(card, id->numid);
 702	list_for_each_entry(kctl, &card->controls, list) {
 703		if (kctl->id.iface != id->iface)
 704			continue;
 705		if (kctl->id.device != id->device)
 706			continue;
 707		if (kctl->id.subdevice != id->subdevice)
 708			continue;
 709		if (strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)))
 710			continue;
 711		if (kctl->id.index > id->index)
 712			continue;
 713		if (kctl->id.index + kctl->count <= id->index)
 714			continue;
 715		return kctl;
 716	}
 717	return NULL;
 718}
 719EXPORT_SYMBOL(snd_ctl_find_id);
 720
 721static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
 722			     unsigned int cmd, void __user *arg)
 723{
 724	struct snd_ctl_card_info *info;
 725
 726	info = kzalloc(sizeof(*info), GFP_KERNEL);
 727	if (! info)
 728		return -ENOMEM;
 729	down_read(&snd_ioctl_rwsem);
 730	info->card = card->number;
 731	strlcpy(info->id, card->id, sizeof(info->id));
 732	strlcpy(info->driver, card->driver, sizeof(info->driver));
 733	strlcpy(info->name, card->shortname, sizeof(info->name));
 734	strlcpy(info->longname, card->longname, sizeof(info->longname));
 735	strlcpy(info->mixername, card->mixername, sizeof(info->mixername));
 736	strlcpy(info->components, card->components, sizeof(info->components));
 737	up_read(&snd_ioctl_rwsem);
 738	if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info))) {
 739		kfree(info);
 740		return -EFAULT;
 741	}
 742	kfree(info);
 743	return 0;
 744}
 745
 746static int snd_ctl_elem_list(struct snd_card *card,
 747			     struct snd_ctl_elem_list __user *_list)
 748{
 749	struct list_head *plist;
 750	struct snd_ctl_elem_list list;
 751	struct snd_kcontrol *kctl;
 752	struct snd_ctl_elem_id *dst, *id;
 753	unsigned int offset, space, jidx;
 754	
 
 755	if (copy_from_user(&list, _list, sizeof(list)))
 756		return -EFAULT;
 757	offset = list.offset;
 758	space = list.space;
 759	/* try limit maximum space */
 760	if (space > 16384)
 761		return -ENOMEM;
 
 762	if (space > 0) {
 763		/* allocate temporary buffer for atomic operation */
 764		dst = vmalloc(space * sizeof(struct snd_ctl_elem_id));
 765		if (dst == NULL)
 766			return -ENOMEM;
 767		down_read(&card->controls_rwsem);
 768		list.count = card->controls_count;
 769		plist = card->controls.next;
 770		while (plist != &card->controls) {
 771			if (offset == 0)
 772				break;
 773			kctl = snd_kcontrol(plist);
 774			if (offset < kctl->count)
 775				break;
 776			offset -= kctl->count;
 777			plist = plist->next;
 778		}
 779		list.used = 0;
 780		id = dst;
 781		while (space > 0 && plist != &card->controls) {
 782			kctl = snd_kcontrol(plist);
 783			for (jidx = offset; space > 0 && jidx < kctl->count; jidx++) {
 784				snd_ctl_build_ioff(id, kctl, jidx);
 785				id++;
 786				space--;
 787				list.used++;
 
 
 788			}
 789			plist = plist->next;
 790			offset = 0;
 791		}
 792		up_read(&card->controls_rwsem);
 793		if (list.used > 0 &&
 794		    copy_to_user(list.pids, dst,
 795				 list.used * sizeof(struct snd_ctl_elem_id))) {
 796			vfree(dst);
 797			return -EFAULT;
 798		}
 799		vfree(dst);
 800	} else {
 801		down_read(&card->controls_rwsem);
 802		list.count = card->controls_count;
 803		up_read(&card->controls_rwsem);
 804	}
 805	if (copy_to_user(_list, &list, sizeof(list)))
 806		return -EFAULT;
 807	return 0;
 
 
 808}
 809
 810static bool validate_element_member_dimension(struct snd_ctl_elem_info *info)
 811{
 812	unsigned int members;
 813	unsigned int i;
 814
 815	if (info->dimen.d[0] == 0)
 816		return true;
 817
 818	members = 1;
 819	for (i = 0; i < ARRAY_SIZE(info->dimen.d); ++i) {
 820		if (info->dimen.d[i] == 0)
 821			break;
 822		members *= info->dimen.d[i];
 823
 824		/*
 825		 * info->count should be validated in advance, to guarantee
 826		 * calculation soundness.
 827		 */
 828		if (members > info->count)
 829			return false;
 830	}
 831
 832	for (++i; i < ARRAY_SIZE(info->dimen.d); ++i) {
 833		if (info->dimen.d[i] > 0)
 834			return false;
 835	}
 836
 837	return members == info->count;
 838}
 839
 840static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
 841			     struct snd_ctl_elem_info *info)
 842{
 843	struct snd_card *card = ctl->card;
 844	struct snd_kcontrol *kctl;
 845	struct snd_kcontrol_volatile *vd;
 846	unsigned int index_offset;
 847	int result;
 848	
 849	down_read(&card->controls_rwsem);
 850	kctl = snd_ctl_find_id(card, &info->id);
 851	if (kctl == NULL) {
 852		up_read(&card->controls_rwsem);
 853		return -ENOENT;
 854	}
 855#ifdef CONFIG_SND_DEBUG
 856	info->access = 0;
 857#endif
 858	result = kctl->info(kctl, info);
 859	if (result >= 0) {
 860		snd_BUG_ON(info->access);
 861		index_offset = snd_ctl_get_ioff(kctl, &info->id);
 862		vd = &kctl->vd[index_offset];
 863		snd_ctl_build_ioff(&info->id, kctl, index_offset);
 864		info->access = vd->access;
 865		if (vd->owner) {
 866			info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
 867			if (vd->owner == ctl)
 868				info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
 869			info->owner = pid_vnr(vd->owner->pid);
 870		} else {
 871			info->owner = -1;
 872		}
 873	}
 874	up_read(&card->controls_rwsem);
 875	return result;
 876}
 877
 878static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
 879				  struct snd_ctl_elem_info __user *_info)
 880{
 881	struct snd_ctl_elem_info info;
 882	int result;
 883
 884	if (copy_from_user(&info, _info, sizeof(info)))
 885		return -EFAULT;
 886	snd_power_lock(ctl->card);
 887	result = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
 888	if (result >= 0)
 889		result = snd_ctl_elem_info(ctl, &info);
 890	snd_power_unlock(ctl->card);
 891	if (result >= 0)
 892		if (copy_to_user(_info, &info, sizeof(info)))
 893			return -EFAULT;
 
 894	return result;
 895}
 896
 897static int snd_ctl_elem_read(struct snd_card *card,
 898			     struct snd_ctl_elem_value *control)
 899{
 900	struct snd_kcontrol *kctl;
 901	struct snd_kcontrol_volatile *vd;
 902	unsigned int index_offset;
 903	int result;
 904
 905	down_read(&card->controls_rwsem);
 906	kctl = snd_ctl_find_id(card, &control->id);
 907	if (kctl == NULL) {
 908		result = -ENOENT;
 909	} else {
 910		index_offset = snd_ctl_get_ioff(kctl, &control->id);
 911		vd = &kctl->vd[index_offset];
 912		if ((vd->access & SNDRV_CTL_ELEM_ACCESS_READ) &&
 913		    kctl->get != NULL) {
 914			snd_ctl_build_ioff(&control->id, kctl, index_offset);
 915			result = kctl->get(kctl, control);
 916		} else
 917			result = -EPERM;
 918	}
 919	up_read(&card->controls_rwsem);
 920	return result;
 921}
 922
 923static int snd_ctl_elem_read_user(struct snd_card *card,
 924				  struct snd_ctl_elem_value __user *_control)
 925{
 926	struct snd_ctl_elem_value *control;
 927	int result;
 928
 929	control = memdup_user(_control, sizeof(*control));
 930	if (IS_ERR(control))
 931		return PTR_ERR(control);
 932
 933	snd_power_lock(card);
 934	result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 935	if (result >= 0)
 936		result = snd_ctl_elem_read(card, control);
 937	snd_power_unlock(card);
 938	if (result >= 0)
 939		if (copy_to_user(_control, control, sizeof(*control)))
 940			result = -EFAULT;
 
 
 
 
 
 
 941	kfree(control);
 942	return result;
 943}
 944
 945static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
 946			      struct snd_ctl_elem_value *control)
 947{
 948	struct snd_kcontrol *kctl;
 949	struct snd_kcontrol_volatile *vd;
 950	unsigned int index_offset;
 951	int result;
 952
 953	down_read(&card->controls_rwsem);
 954	kctl = snd_ctl_find_id(card, &control->id);
 955	if (kctl == NULL) {
 956		result = -ENOENT;
 957	} else {
 958		index_offset = snd_ctl_get_ioff(kctl, &control->id);
 959		vd = &kctl->vd[index_offset];
 960		if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) ||
 961		    kctl->put == NULL ||
 962		    (file && vd->owner && vd->owner != file)) {
 963			result = -EPERM;
 964		} else {
 965			snd_ctl_build_ioff(&control->id, kctl, index_offset);
 966			result = kctl->put(kctl, control);
 967		}
 968		if (result > 0) {
 969			struct snd_ctl_elem_id id = control->id;
 970			up_read(&card->controls_rwsem);
 971			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, &id);
 972			return 0;
 973		}
 974	}
 975	up_read(&card->controls_rwsem);
 976	return result;
 
 
 
 
 
 
 
 
 
 
 977}
 978
 979static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
 980				   struct snd_ctl_elem_value __user *_control)
 981{
 982	struct snd_ctl_elem_value *control;
 983	struct snd_card *card;
 984	int result;
 985
 986	control = memdup_user(_control, sizeof(*control));
 987	if (IS_ERR(control))
 988		return PTR_ERR(control);
 989
 990	card = file->card;
 991	snd_power_lock(card);
 992	result = snd_power_wait(card, SNDRV_CTL_POWER_D0);
 993	if (result >= 0)
 994		result = snd_ctl_elem_write(card, file, control);
 995	snd_power_unlock(card);
 996	if (result >= 0)
 997		if (copy_to_user(_control, control, sizeof(*control)))
 998			result = -EFAULT;
 
 
 
 
 
 
 999	kfree(control);
1000	return result;
1001}
1002
1003static int snd_ctl_elem_lock(struct snd_ctl_file *file,
1004			     struct snd_ctl_elem_id __user *_id)
1005{
1006	struct snd_card *card = file->card;
1007	struct snd_ctl_elem_id id;
1008	struct snd_kcontrol *kctl;
1009	struct snd_kcontrol_volatile *vd;
1010	int result;
1011	
1012	if (copy_from_user(&id, _id, sizeof(id)))
1013		return -EFAULT;
1014	down_write(&card->controls_rwsem);
1015	kctl = snd_ctl_find_id(card, &id);
1016	if (kctl == NULL) {
1017		result = -ENOENT;
1018	} else {
1019		vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1020		if (vd->owner != NULL)
1021			result = -EBUSY;
1022		else {
1023			vd->owner = file;
1024			result = 0;
1025		}
1026	}
1027	up_write(&card->controls_rwsem);
1028	return result;
1029}
1030
1031static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
1032			       struct snd_ctl_elem_id __user *_id)
1033{
1034	struct snd_card *card = file->card;
1035	struct snd_ctl_elem_id id;
1036	struct snd_kcontrol *kctl;
1037	struct snd_kcontrol_volatile *vd;
1038	int result;
1039	
1040	if (copy_from_user(&id, _id, sizeof(id)))
1041		return -EFAULT;
1042	down_write(&card->controls_rwsem);
1043	kctl = snd_ctl_find_id(card, &id);
1044	if (kctl == NULL) {
1045		result = -ENOENT;
1046	} else {
1047		vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
1048		if (vd->owner == NULL)
1049			result = -EINVAL;
1050		else if (vd->owner != file)
1051			result = -EPERM;
1052		else {
1053			vd->owner = NULL;
1054			result = 0;
1055		}
1056	}
1057	up_write(&card->controls_rwsem);
1058	return result;
1059}
1060
1061struct user_element {
1062	struct snd_ctl_elem_info info;
1063	struct snd_card *card;
1064	char *elem_data;		/* element data */
1065	unsigned long elem_data_size;	/* size of element data in bytes */
1066	void *tlv_data;			/* TLV data */
1067	unsigned long tlv_data_size;	/* TLV data size */
1068	void *priv_data;		/* private data (like strings for enumerated type) */
1069};
1070
1071static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
1072				  struct snd_ctl_elem_info *uinfo)
1073{
1074	struct user_element *ue = kcontrol->private_data;
1075	unsigned int offset;
1076
1077	offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1078	*uinfo = ue->info;
1079	snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1080
1081	return 0;
1082}
1083
1084static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
1085				       struct snd_ctl_elem_info *uinfo)
1086{
1087	struct user_element *ue = kcontrol->private_data;
1088	const char *names;
1089	unsigned int item;
1090	unsigned int offset;
1091
1092	item = uinfo->value.enumerated.item;
1093
1094	offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
1095	*uinfo = ue->info;
1096	snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
1097
1098	item = min(item, uinfo->value.enumerated.items - 1);
1099	uinfo->value.enumerated.item = item;
1100
1101	names = ue->priv_data;
1102	for (; item > 0; --item)
1103		names += strlen(names) + 1;
1104	strcpy(uinfo->value.enumerated.name, names);
1105
1106	return 0;
1107}
1108
1109static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
1110				 struct snd_ctl_elem_value *ucontrol)
1111{
1112	struct user_element *ue = kcontrol->private_data;
1113	unsigned int size = ue->elem_data_size;
1114	char *src = ue->elem_data +
1115			snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1116
1117	mutex_lock(&ue->card->user_ctl_lock);
1118	memcpy(&ucontrol->value, src, size);
1119	mutex_unlock(&ue->card->user_ctl_lock);
1120	return 0;
1121}
1122
1123static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
1124				 struct snd_ctl_elem_value *ucontrol)
1125{
1126	int change;
1127	struct user_element *ue = kcontrol->private_data;
1128	unsigned int size = ue->elem_data_size;
1129	char *dst = ue->elem_data +
1130			snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
1131
1132	mutex_lock(&ue->card->user_ctl_lock);
1133	change = memcmp(&ucontrol->value, dst, size) != 0;
1134	if (change)
1135		memcpy(dst, &ucontrol->value, size);
1136	mutex_unlock(&ue->card->user_ctl_lock);
1137	return change;
1138}
1139
1140static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kcontrol,
1141				 int op_flag,
1142				 unsigned int size,
1143				 unsigned int __user *tlv)
1144{
1145	struct user_element *ue = kcontrol->private_data;
1146	int change = 0;
1147	void *new_data;
 
 
 
1148
1149	if (op_flag == SNDRV_CTL_TLV_OP_WRITE) {
1150		if (size > 1024 * 128)	/* sane value */
1151			return -EINVAL;
1152
1153		new_data = memdup_user(tlv, size);
1154		if (IS_ERR(new_data))
1155			return PTR_ERR(new_data);
1156		mutex_lock(&ue->card->user_ctl_lock);
1157		change = ue->tlv_data_size != size;
1158		if (!change)
1159			change = memcmp(ue->tlv_data, new_data, size);
1160		kfree(ue->tlv_data);
1161		ue->tlv_data = new_data;
1162		ue->tlv_data_size = size;
1163		mutex_unlock(&ue->card->user_ctl_lock);
1164	} else {
1165		int ret = 0;
1166
1167		mutex_lock(&ue->card->user_ctl_lock);
1168		if (!ue->tlv_data_size || !ue->tlv_data) {
1169			ret = -ENXIO;
1170			goto err_unlock;
1171		}
1172		if (size < ue->tlv_data_size) {
1173			ret = -ENOSPC;
1174			goto err_unlock;
1175		}
1176		if (copy_to_user(tlv, ue->tlv_data, ue->tlv_data_size))
1177			ret = -EFAULT;
1178err_unlock:
1179		mutex_unlock(&ue->card->user_ctl_lock);
1180		if (ret)
1181			return ret;
1182	}
 
1183	return change;
1184}
1185
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1186static int snd_ctl_elem_init_enum_names(struct user_element *ue)
1187{
1188	char *names, *p;
1189	size_t buf_len, name_len;
1190	unsigned int i;
1191	const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
1192
1193	if (ue->info.value.enumerated.names_length > 64 * 1024)
1194		return -EINVAL;
1195
1196	names = memdup_user((const void __user *)user_ptrval,
1197		ue->info.value.enumerated.names_length);
1198	if (IS_ERR(names))
1199		return PTR_ERR(names);
1200
1201	/* check that there are enough valid names */
1202	buf_len = ue->info.value.enumerated.names_length;
1203	p = names;
1204	for (i = 0; i < ue->info.value.enumerated.items; ++i) {
1205		name_len = strnlen(p, buf_len);
1206		if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
1207			kfree(names);
1208			return -EINVAL;
1209		}
1210		p += name_len + 1;
1211		buf_len -= name_len + 1;
1212	}
1213
1214	ue->priv_data = names;
1215	ue->info.value.enumerated.names_ptr = 0;
1216
1217	return 0;
1218}
1219
1220static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
1221{
1222	struct user_element *ue = kcontrol->private_data;
1223
1224	kfree(ue->tlv_data);
1225	kfree(ue->priv_data);
1226	kfree(ue);
1227}
1228
1229static int snd_ctl_elem_add(struct snd_ctl_file *file,
1230			    struct snd_ctl_elem_info *info, int replace)
1231{
1232	/* The capacity of struct snd_ctl_elem_value.value.*/
1233	static const unsigned int value_sizes[] = {
1234		[SNDRV_CTL_ELEM_TYPE_BOOLEAN]	= sizeof(long),
1235		[SNDRV_CTL_ELEM_TYPE_INTEGER]	= sizeof(long),
1236		[SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
1237		[SNDRV_CTL_ELEM_TYPE_BYTES]	= sizeof(unsigned char),
1238		[SNDRV_CTL_ELEM_TYPE_IEC958]	= sizeof(struct snd_aes_iec958),
1239		[SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
1240	};
1241	static const unsigned int max_value_counts[] = {
1242		[SNDRV_CTL_ELEM_TYPE_BOOLEAN]	= 128,
1243		[SNDRV_CTL_ELEM_TYPE_INTEGER]	= 128,
1244		[SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
1245		[SNDRV_CTL_ELEM_TYPE_BYTES]	= 512,
1246		[SNDRV_CTL_ELEM_TYPE_IEC958]	= 1,
1247		[SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
1248	};
1249	struct snd_card *card = file->card;
1250	struct snd_kcontrol *kctl;
1251	unsigned int count;
1252	unsigned int access;
1253	long private_size;
1254	struct user_element *ue;
1255	unsigned int offset;
1256	int err;
1257
1258	if (!*info->id.name)
1259		return -EINVAL;
1260	if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
1261		return -EINVAL;
1262
1263	/* Delete a control to replace them if needed. */
1264	if (replace) {
1265		info->id.numid = 0;
1266		err = snd_ctl_remove_user_ctl(file, &info->id);
1267		if (err)
1268			return err;
1269	}
1270
1271	/*
1272	 * The number of userspace controls are counted control by control,
1273	 * not element by element.
1274	 */
1275	if (card->user_ctl_count + 1 > MAX_USER_CONTROLS)
1276		return -ENOMEM;
1277
1278	/* Check the number of elements for this userspace control. */
1279	count = info->owner;
1280	if (count == 0)
1281		count = 1;
1282
1283	/* Arrange access permissions if needed. */
1284	access = info->access;
1285	if (access == 0)
1286		access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
1287	access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
1288		   SNDRV_CTL_ELEM_ACCESS_INACTIVE |
1289		   SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE);
1290	if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE)
 
 
1291		access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
1292	access |= SNDRV_CTL_ELEM_ACCESS_USER;
1293
1294	/*
1295	 * Check information and calculate the size of data specific to
1296	 * this userspace control.
1297	 */
1298	if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
1299	    info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64)
1300		return -EINVAL;
1301	if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
1302	    info->value.enumerated.items == 0)
1303		return -EINVAL;
1304	if (info->count < 1 ||
1305	    info->count > max_value_counts[info->type])
1306		return -EINVAL;
1307	if (!validate_element_member_dimension(info))
1308		return -EINVAL;
1309	private_size = value_sizes[info->type] * info->count;
1310
1311	/*
1312	 * Keep memory object for this userspace control. After passing this
1313	 * code block, the instance should be freed by snd_ctl_free_one().
1314	 *
1315	 * Note that these elements in this control are locked.
1316	 */
1317	err = snd_ctl_new(&kctl, count, access, file);
1318	if (err < 0)
1319		return err;
1320	memcpy(&kctl->id, &info->id, sizeof(kctl->id));
1321	kctl->private_data = kzalloc(sizeof(struct user_element) + private_size * count,
1322				     GFP_KERNEL);
1323	if (kctl->private_data == NULL) {
1324		kfree(kctl);
1325		return -ENOMEM;
1326	}
1327	kctl->private_free = snd_ctl_elem_user_free;
1328
1329	/* Set private data for this userspace control. */
1330	ue = (struct user_element *)kctl->private_data;
1331	ue->card = card;
1332	ue->info = *info;
1333	ue->info.access = 0;
1334	ue->elem_data = (char *)ue + sizeof(*ue);
1335	ue->elem_data_size = private_size;
1336	if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
1337		err = snd_ctl_elem_init_enum_names(ue);
1338		if (err < 0) {
1339			snd_ctl_free_one(kctl);
1340			return err;
1341		}
1342	}
1343
1344	/* Set callback functions. */
1345	if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
1346		kctl->info = snd_ctl_elem_user_enum_info;
1347	else
1348		kctl->info = snd_ctl_elem_user_info;
1349	if (access & SNDRV_CTL_ELEM_ACCESS_READ)
1350		kctl->get = snd_ctl_elem_user_get;
1351	if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
1352		kctl->put = snd_ctl_elem_user_put;
1353	if (access & SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE)
1354		kctl->tlv.c = snd_ctl_elem_user_tlv;
1355
1356	/* This function manage to free the instance on failure. */
1357	err = snd_ctl_add(card, kctl);
1358	if (err < 0)
1359		return err;
1360	offset = snd_ctl_get_ioff(kctl, &info->id);
1361	snd_ctl_build_ioff(&info->id, kctl, offset);
1362	/*
1363	 * Here we cannot fill any field for the number of elements added by
1364	 * this operation because there're no specific fields. The usage of
1365	 * 'owner' field for this purpose may cause any bugs to userspace
1366	 * applications because the field originally means PID of a process
1367	 * which locks the element.
1368	 */
1369
1370	down_write(&card->controls_rwsem);
1371	card->user_ctl_count++;
1372	up_write(&card->controls_rwsem);
1373
1374	return 0;
1375}
1376
1377static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
1378				 struct snd_ctl_elem_info __user *_info, int replace)
1379{
1380	struct snd_ctl_elem_info info;
1381	int err;
1382
1383	if (copy_from_user(&info, _info, sizeof(info)))
1384		return -EFAULT;
1385	err = snd_ctl_elem_add(file, &info, replace);
1386	if (err < 0)
1387		return err;
1388	if (copy_to_user(_info, &info, sizeof(info))) {
1389		snd_ctl_remove_user_ctl(file, &info.id);
1390		return -EFAULT;
1391	}
1392
1393	return 0;
1394}
1395
1396static int snd_ctl_elem_remove(struct snd_ctl_file *file,
1397			       struct snd_ctl_elem_id __user *_id)
1398{
1399	struct snd_ctl_elem_id id;
1400
1401	if (copy_from_user(&id, _id, sizeof(id)))
1402		return -EFAULT;
1403	return snd_ctl_remove_user_ctl(file, &id);
1404}
1405
1406static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
1407{
1408	int subscribe;
1409	if (get_user(subscribe, ptr))
1410		return -EFAULT;
1411	if (subscribe < 0) {
1412		subscribe = file->subscribed;
1413		if (put_user(subscribe, ptr))
1414			return -EFAULT;
1415		return 0;
1416	}
1417	if (subscribe) {
1418		file->subscribed = 1;
1419		return 0;
1420	} else if (file->subscribed) {
1421		snd_ctl_empty_read_queue(file);
1422		file->subscribed = 0;
1423	}
1424	return 0;
1425}
1426
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1427static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
1428                             struct snd_ctl_tlv __user *_tlv,
1429                             int op_flag)
1430{
1431	struct snd_card *card = file->card;
1432	struct snd_ctl_tlv tlv;
 
1433	struct snd_kcontrol *kctl;
 
1434	struct snd_kcontrol_volatile *vd;
1435	unsigned int len;
1436	int err = 0;
1437
1438	if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
1439		return -EFAULT;
1440	if (tlv.length < sizeof(unsigned int) * 2)
 
 
1441		return -EINVAL;
1442	if (!tlv.numid)
 
 
1443		return -EINVAL;
1444	down_read(&card->controls_rwsem);
1445	kctl = snd_ctl_find_numid(card, tlv.numid);
1446	if (kctl == NULL) {
1447		err = -ENOENT;
1448		goto __kctl_end;
1449	}
1450	if (kctl->tlv.p == NULL) {
1451		err = -ENXIO;
1452		goto __kctl_end;
1453	}
1454	vd = &kctl->vd[tlv.numid - kctl->id.numid];
1455	if ((op_flag == SNDRV_CTL_TLV_OP_READ &&
1456	     (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
1457	    (op_flag == SNDRV_CTL_TLV_OP_WRITE &&
1458	     (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
1459	    (op_flag == SNDRV_CTL_TLV_OP_CMD &&
1460	     (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
1461	    	err = -ENXIO;
1462	    	goto __kctl_end;
1463	}
1464	if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
1465		if (vd->owner != NULL && vd->owner != file) {
1466			err = -EPERM;
1467			goto __kctl_end;
1468		}
1469		err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv);
1470		if (err > 0) {
1471			struct snd_ctl_elem_id id = kctl->id;
1472			up_read(&card->controls_rwsem);
1473			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &id);
1474			return 0;
1475		}
1476	} else {
1477		if (op_flag != SNDRV_CTL_TLV_OP_READ) {
1478			err = -ENXIO;
1479			goto __kctl_end;
1480		}
1481		len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
1482		if (tlv.length < len) {
1483			err = -ENOMEM;
1484			goto __kctl_end;
1485		}
1486		if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
1487			err = -EFAULT;
1488	}
1489      __kctl_end:
1490	up_read(&card->controls_rwsem);
1491	return err;
1492}
1493
1494static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1495{
1496	struct snd_ctl_file *ctl;
1497	struct snd_card *card;
1498	struct snd_kctl_ioctl *p;
1499	void __user *argp = (void __user *)arg;
1500	int __user *ip = argp;
1501	int err;
1502
1503	ctl = file->private_data;
1504	card = ctl->card;
1505	if (snd_BUG_ON(!card))
1506		return -ENXIO;
1507	switch (cmd) {
1508	case SNDRV_CTL_IOCTL_PVERSION:
1509		return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
1510	case SNDRV_CTL_IOCTL_CARD_INFO:
1511		return snd_ctl_card_info(card, ctl, cmd, argp);
1512	case SNDRV_CTL_IOCTL_ELEM_LIST:
1513		return snd_ctl_elem_list(card, argp);
1514	case SNDRV_CTL_IOCTL_ELEM_INFO:
1515		return snd_ctl_elem_info_user(ctl, argp);
1516	case SNDRV_CTL_IOCTL_ELEM_READ:
1517		return snd_ctl_elem_read_user(card, argp);
1518	case SNDRV_CTL_IOCTL_ELEM_WRITE:
1519		return snd_ctl_elem_write_user(ctl, argp);
1520	case SNDRV_CTL_IOCTL_ELEM_LOCK:
1521		return snd_ctl_elem_lock(ctl, argp);
1522	case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
1523		return snd_ctl_elem_unlock(ctl, argp);
1524	case SNDRV_CTL_IOCTL_ELEM_ADD:
1525		return snd_ctl_elem_add_user(ctl, argp, 0);
1526	case SNDRV_CTL_IOCTL_ELEM_REPLACE:
1527		return snd_ctl_elem_add_user(ctl, argp, 1);
1528	case SNDRV_CTL_IOCTL_ELEM_REMOVE:
1529		return snd_ctl_elem_remove(ctl, argp);
1530	case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
1531		return snd_ctl_subscribe_events(ctl, ip);
1532	case SNDRV_CTL_IOCTL_TLV_READ:
1533		return snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
 
 
 
1534	case SNDRV_CTL_IOCTL_TLV_WRITE:
1535		return snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
 
 
 
1536	case SNDRV_CTL_IOCTL_TLV_COMMAND:
1537		return snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
 
 
 
1538	case SNDRV_CTL_IOCTL_POWER:
1539		return -ENOPROTOOPT;
1540	case SNDRV_CTL_IOCTL_POWER_STATE:
1541#ifdef CONFIG_PM
1542		return put_user(card->power_state, ip) ? -EFAULT : 0;
1543#else
1544		return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
1545#endif
1546	}
1547	down_read(&snd_ioctl_rwsem);
1548	list_for_each_entry(p, &snd_control_ioctls, list) {
1549		err = p->fioctl(card, ctl, cmd, arg);
1550		if (err != -ENOIOCTLCMD) {
1551			up_read(&snd_ioctl_rwsem);
1552			return err;
1553		}
1554	}
1555	up_read(&snd_ioctl_rwsem);
1556	dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
1557	return -ENOTTY;
1558}
1559
1560static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
1561			    size_t count, loff_t * offset)
1562{
1563	struct snd_ctl_file *ctl;
1564	int err = 0;
1565	ssize_t result = 0;
1566
1567	ctl = file->private_data;
1568	if (snd_BUG_ON(!ctl || !ctl->card))
1569		return -ENXIO;
1570	if (!ctl->subscribed)
1571		return -EBADFD;
1572	if (count < sizeof(struct snd_ctl_event))
1573		return -EINVAL;
1574	spin_lock_irq(&ctl->read_lock);
1575	while (count >= sizeof(struct snd_ctl_event)) {
1576		struct snd_ctl_event ev;
1577		struct snd_kctl_event *kev;
1578		while (list_empty(&ctl->events)) {
1579			wait_queue_t wait;
1580			if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1581				err = -EAGAIN;
1582				goto __end_lock;
1583			}
1584			init_waitqueue_entry(&wait, current);
1585			add_wait_queue(&ctl->change_sleep, &wait);
1586			set_current_state(TASK_INTERRUPTIBLE);
1587			spin_unlock_irq(&ctl->read_lock);
1588			schedule();
1589			remove_wait_queue(&ctl->change_sleep, &wait);
1590			if (ctl->card->shutdown)
1591				return -ENODEV;
1592			if (signal_pending(current))
1593				return -ERESTARTSYS;
1594			spin_lock_irq(&ctl->read_lock);
1595		}
1596		kev = snd_kctl_event(ctl->events.next);
1597		ev.type = SNDRV_CTL_EVENT_ELEM;
1598		ev.data.elem.mask = kev->mask;
1599		ev.data.elem.id = kev->id;
1600		list_del(&kev->list);
1601		spin_unlock_irq(&ctl->read_lock);
1602		kfree(kev);
1603		if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
1604			err = -EFAULT;
1605			goto __end;
1606		}
1607		spin_lock_irq(&ctl->read_lock);
1608		buffer += sizeof(struct snd_ctl_event);
1609		count -= sizeof(struct snd_ctl_event);
1610		result += sizeof(struct snd_ctl_event);
1611	}
1612      __end_lock:
1613	spin_unlock_irq(&ctl->read_lock);
1614      __end:
1615      	return result > 0 ? result : err;
1616}
1617
1618static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
1619{
1620	unsigned int mask;
1621	struct snd_ctl_file *ctl;
1622
1623	ctl = file->private_data;
1624	if (!ctl->subscribed)
1625		return 0;
1626	poll_wait(file, &ctl->change_sleep, wait);
1627
1628	mask = 0;
1629	if (!list_empty(&ctl->events))
1630		mask |= POLLIN | POLLRDNORM;
1631
1632	return mask;
1633}
1634
1635/*
1636 * register the device-specific control-ioctls.
1637 * called from each device manager like pcm.c, hwdep.c, etc.
1638 */
1639static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
1640{
1641	struct snd_kctl_ioctl *pn;
1642
1643	pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
1644	if (pn == NULL)
1645		return -ENOMEM;
1646	pn->fioctl = fcn;
1647	down_write(&snd_ioctl_rwsem);
1648	list_add_tail(&pn->list, lists);
1649	up_write(&snd_ioctl_rwsem);
1650	return 0;
1651}
1652
1653/**
1654 * snd_ctl_register_ioctl - register the device-specific control-ioctls
1655 * @fcn: ioctl callback function
1656 *
1657 * called from each device manager like pcm.c, hwdep.c, etc.
1658 */
1659int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
1660{
1661	return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
1662}
1663EXPORT_SYMBOL(snd_ctl_register_ioctl);
1664
1665#ifdef CONFIG_COMPAT
1666/**
1667 * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
1668 * control-ioctls
1669 * @fcn: ioctl callback function
1670 */
1671int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1672{
1673	return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
1674}
1675EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
1676#endif
1677
1678/*
1679 * de-register the device-specific control-ioctls.
1680 */
1681static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
1682				     struct list_head *lists)
1683{
1684	struct snd_kctl_ioctl *p;
1685
1686	if (snd_BUG_ON(!fcn))
1687		return -EINVAL;
1688	down_write(&snd_ioctl_rwsem);
1689	list_for_each_entry(p, lists, list) {
1690		if (p->fioctl == fcn) {
1691			list_del(&p->list);
1692			up_write(&snd_ioctl_rwsem);
1693			kfree(p);
1694			return 0;
1695		}
1696	}
1697	up_write(&snd_ioctl_rwsem);
1698	snd_BUG();
1699	return -EINVAL;
1700}
1701
1702/**
1703 * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
1704 * @fcn: ioctl callback function to unregister
1705 */
1706int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
1707{
1708	return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
1709}
1710EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
1711
1712#ifdef CONFIG_COMPAT
1713/**
1714 * snd_ctl_unregister_ioctl - de-register the device-specific compat 32bit
1715 * control-ioctls
1716 * @fcn: ioctl callback function to unregister
1717 */
1718int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
1719{
1720	return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
1721}
1722EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
1723#endif
1724
1725static int snd_ctl_fasync(int fd, struct file * file, int on)
1726{
1727	struct snd_ctl_file *ctl;
1728
1729	ctl = file->private_data;
1730	return fasync_helper(fd, file, on, &ctl->fasync);
1731}
1732
1733/* return the preferred subdevice number if already assigned;
1734 * otherwise return -1
1735 */
1736int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
1737{
1738	struct snd_ctl_file *kctl;
1739	int subdevice = -1;
1740
1741	read_lock(&card->ctl_files_rwlock);
1742	list_for_each_entry(kctl, &card->ctl_files, list) {
1743		if (kctl->pid == task_pid(current)) {
1744			subdevice = kctl->preferred_subdevice[type];
1745			if (subdevice != -1)
1746				break;
1747		}
1748	}
1749	read_unlock(&card->ctl_files_rwlock);
1750	return subdevice;
1751}
1752EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
1753
1754/*
1755 * ioctl32 compat
1756 */
1757#ifdef CONFIG_COMPAT
1758#include "control_compat.c"
1759#else
1760#define snd_ctl_ioctl_compat	NULL
1761#endif
1762
1763/*
1764 *  INIT PART
1765 */
1766
1767static const struct file_operations snd_ctl_f_ops =
1768{
1769	.owner =	THIS_MODULE,
1770	.read =		snd_ctl_read,
1771	.open =		snd_ctl_open,
1772	.release =	snd_ctl_release,
1773	.llseek =	no_llseek,
1774	.poll =		snd_ctl_poll,
1775	.unlocked_ioctl =	snd_ctl_ioctl,
1776	.compat_ioctl =	snd_ctl_ioctl_compat,
1777	.fasync =	snd_ctl_fasync,
1778};
1779
1780/*
1781 * registration of the control device
1782 */
1783static int snd_ctl_dev_register(struct snd_device *device)
1784{
1785	struct snd_card *card = device->device_data;
1786
1787	return snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
1788				   &snd_ctl_f_ops, card, &card->ctl_dev);
1789}
1790
1791/*
1792 * disconnection of the control device
1793 */
1794static int snd_ctl_dev_disconnect(struct snd_device *device)
1795{
1796	struct snd_card *card = device->device_data;
1797	struct snd_ctl_file *ctl;
1798
1799	read_lock(&card->ctl_files_rwlock);
1800	list_for_each_entry(ctl, &card->ctl_files, list) {
1801		wake_up(&ctl->change_sleep);
1802		kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
1803	}
1804	read_unlock(&card->ctl_files_rwlock);
1805
1806	return snd_unregister_device(&card->ctl_dev);
1807}
1808
1809/*
1810 * free all controls
1811 */
1812static int snd_ctl_dev_free(struct snd_device *device)
1813{
1814	struct snd_card *card = device->device_data;
1815	struct snd_kcontrol *control;
1816
1817	down_write(&card->controls_rwsem);
1818	while (!list_empty(&card->controls)) {
1819		control = snd_kcontrol(card->controls.next);
1820		snd_ctl_remove(card, control);
1821	}
1822	up_write(&card->controls_rwsem);
1823	put_device(&card->ctl_dev);
1824	return 0;
1825}
1826
1827/*
1828 * create control core:
1829 * called from init.c
1830 */
1831int snd_ctl_create(struct snd_card *card)
1832{
1833	static struct snd_device_ops ops = {
1834		.dev_free = snd_ctl_dev_free,
1835		.dev_register =	snd_ctl_dev_register,
1836		.dev_disconnect = snd_ctl_dev_disconnect,
1837	};
1838	int err;
1839
1840	if (snd_BUG_ON(!card))
1841		return -ENXIO;
1842	if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
1843		return -ENXIO;
1844
1845	snd_device_initialize(&card->ctl_dev, card);
1846	dev_set_name(&card->ctl_dev, "controlC%d", card->number);
1847
1848	err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
1849	if (err < 0)
1850		put_device(&card->ctl_dev);
1851	return err;
1852}
1853
1854/*
1855 * Frequently used control callbacks/helpers
1856 */
1857
1858/**
1859 * snd_ctl_boolean_mono_info - Helper function for a standard boolean info
1860 * callback with a mono channel
1861 * @kcontrol: the kcontrol instance
1862 * @uinfo: info to store
1863 *
1864 * This is a function that can be used as info callback for a standard
1865 * boolean control with a single mono channel.
1866 */
1867int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
1868			      struct snd_ctl_elem_info *uinfo)
1869{
1870	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1871	uinfo->count = 1;
1872	uinfo->value.integer.min = 0;
1873	uinfo->value.integer.max = 1;
1874	return 0;
1875}
1876EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
1877
1878/**
1879 * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
1880 * callback with stereo two channels
1881 * @kcontrol: the kcontrol instance
1882 * @uinfo: info to store
1883 *
1884 * This is a function that can be used as info callback for a standard
1885 * boolean control with stereo two channels.
1886 */
1887int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
1888				struct snd_ctl_elem_info *uinfo)
1889{
1890	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
1891	uinfo->count = 2;
1892	uinfo->value.integer.min = 0;
1893	uinfo->value.integer.max = 1;
1894	return 0;
1895}
1896EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
1897
1898/**
1899 * snd_ctl_enum_info - fills the info structure for an enumerated control
1900 * @info: the structure to be filled
1901 * @channels: the number of the control's channels; often one
1902 * @items: the number of control values; also the size of @names
1903 * @names: an array containing the names of all control values
1904 *
1905 * Sets all required fields in @info to their appropriate values.
1906 * If the control's accessibility is not the default (readable and writable),
1907 * the caller has to fill @info->access.
1908 *
1909 * Return: Zero.
1910 */
1911int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
1912		      unsigned int items, const char *const names[])
1913{
1914	info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
1915	info->count = channels;
1916	info->value.enumerated.items = items;
1917	if (!items)
1918		return 0;
1919	if (info->value.enumerated.item >= items)
1920		info->value.enumerated.item = items - 1;
1921	WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
1922	     "ALSA: too long item name '%s'\n",
1923	     names[info->value.enumerated.item]);
1924	strlcpy(info->value.enumerated.name,
1925		names[info->value.enumerated.item],
1926		sizeof(info->value.enumerated.name));
1927	return 0;
1928}
1929EXPORT_SYMBOL(snd_ctl_enum_info);