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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Routines for driver control interface4 * 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 102828 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_COMPAT38static LIST_HEAD(snd_control_compat_ioctls);39#endif40static 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->controls_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->controls_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 change141 * @card: the card to send notification142 * @mask: the event mask, SNDRV_CTL_EVENT_*143 * @id: the ctl element id to send notification144 *145 * This function adds an event record with the given id and mask, appends146 * to the list and wakes up the user-space for notification. This can be147 * 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->controls_rwlock);161#if IS_ENABLED(CONFIG_SND_MIXER_OSS)162 card->mixer_oss_change_count++;163#endif164 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 change192 * @card: the card to send notification193 * @mask: the event mask, SNDRV_CTL_EVENT_*194 * @kctl: the pointer with the control instance195 * @ioff: the additional offset to the control index196 *197 * This function calls snd_ctl_notify() and does additional jobs198 * 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 elements217 * @kctl: the pointer to store new control instance218 * @count: the number of elements in this control219 * @access: the default access flags for elements in this control220 * @file: given when locking these elements221 *222 * Allocates a memory object for a new control instance. The instance has223 * elements as many as the given number (@count). Each element has given224 * access permissions (@access). Each element is locked when @file is given.225 *226 * Return: 0 on success, error code on failure227 */228static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,229 unsigned int access, struct snd_ctl_file *file)230{231 unsigned int idx;232 233 if (count == 0 || count > MAX_CONTROL_COUNT)234 return -EINVAL;235 236 *kctl = kzalloc(struct_size(*kctl, vd, count), GFP_KERNEL);237 if (!*kctl)238 return -ENOMEM;239 240 (*kctl)->count = count;241 for (idx = 0; idx < count; idx++) {242 (*kctl)->vd[idx].access = access;243 (*kctl)->vd[idx].owner = file;244 }245 246 return 0;247}248 249/**250 * snd_ctl_new1 - create a control instance from the template251 * @ncontrol: the initialization record252 * @private_data: the private data to set253 *254 * Allocates a new struct snd_kcontrol instance and initialize from the given255 * template. When the access field of ncontrol is 0, it's assumed as256 * 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 instance317 * @kcontrol: the control instance318 *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_LOOKUP379/* Compute a hash key for the corresponding ctl id380 * 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 37384static 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(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 scoped_guard(write_lock_irq, &card->controls_rwlock) {495 list_add_tail(&kcontrol->list, &card->controls);496 card->controls_count += kcontrol->count;497 kcontrol->id.numid = card->last_numid + 1;498 card->last_numid += kcontrol->count;499 }500 501 add_hash_entries(card, kcontrol);502 503 for (idx = 0; idx < kcontrol->count; idx++)504 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_ADD, kcontrol, idx);505 506 return 0;507}508 509static int snd_ctl_add_replace(struct snd_card *card,510 struct snd_kcontrol *kcontrol,511 enum snd_ctl_add_mode mode)512{513 int err = -EINVAL;514 515 if (! kcontrol)516 return err;517 if (snd_BUG_ON(!card || !kcontrol->info))518 goto error;519 520 scoped_guard(rwsem_write, &card->controls_rwsem)521 err = __snd_ctl_add_replace(card, kcontrol, mode);522 523 if (err < 0)524 goto error;525 return 0;526 527 error:528 snd_ctl_free_one(kcontrol);529 return err;530}531 532/**533 * snd_ctl_add - add the control instance to the card534 * @card: the card instance535 * @kcontrol: the control instance to add536 *537 * Adds the control instance created via snd_ctl_new() or538 * snd_ctl_new1() to the given card. Assigns also an unique539 * numid used for fast search.540 *541 * It frees automatically the control which cannot be added.542 *543 * Return: Zero if successful, or a negative error code on failure.544 *545 */546int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)547{548 return snd_ctl_add_replace(card, kcontrol, CTL_ADD_EXCLUSIVE);549}550EXPORT_SYMBOL(snd_ctl_add);551 552/**553 * snd_ctl_replace - replace the control instance of the card554 * @card: the card instance555 * @kcontrol: the control instance to replace556 * @add_on_replace: add the control if not already added557 *558 * Replaces the given control. If the given control does not exist559 * and the add_on_replace flag is set, the control is added. If the560 * control exists, it is destroyed first.561 *562 * It frees automatically the control which cannot be added or replaced.563 *564 * Return: Zero if successful, or a negative error code on failure.565 */566int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,567 bool add_on_replace)568{569 return snd_ctl_add_replace(card, kcontrol,570 add_on_replace ? CTL_ADD_ON_REPLACE : CTL_REPLACE);571}572EXPORT_SYMBOL(snd_ctl_replace);573 574static int __snd_ctl_remove(struct snd_card *card,575 struct snd_kcontrol *kcontrol,576 bool remove_hash)577{578 unsigned int idx;579 580 lockdep_assert_held_write(&card->controls_rwsem);581 582 if (snd_BUG_ON(!card || !kcontrol))583 return -EINVAL;584 585 if (remove_hash)586 remove_hash_entries(card, kcontrol);587 588 scoped_guard(write_lock_irq, &card->controls_rwlock) {589 list_del(&kcontrol->list);590 card->controls_count -= kcontrol->count;591 }592 593 for (idx = 0; idx < kcontrol->count; idx++)594 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_REMOVE, kcontrol, idx);595 snd_ctl_free_one(kcontrol);596 return 0;597}598 599static inline int snd_ctl_remove_locked(struct snd_card *card,600 struct snd_kcontrol *kcontrol)601{602 return __snd_ctl_remove(card, kcontrol, true);603}604 605/**606 * snd_ctl_remove - remove the control from the card and release it607 * @card: the card instance608 * @kcontrol: the control instance to remove609 *610 * Removes the control from the card and then releases the instance.611 * You don't need to call snd_ctl_free_one().612 * Passing NULL to @kcontrol argument is allowed as noop.613 *614 * Return: 0 if successful, or a negative error code on failure.615 *616 * Note that this function takes card->controls_rwsem lock internally.617 */618int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)619{620 if (!kcontrol)621 return 0;622 guard(rwsem_write)(&card->controls_rwsem);623 return snd_ctl_remove_locked(card, kcontrol);624}625EXPORT_SYMBOL(snd_ctl_remove);626 627/**628 * snd_ctl_remove_id - remove the control of the given id and release it629 * @card: the card instance630 * @id: the control id to remove631 *632 * Finds the control instance with the given id, removes it from the633 * card list and releases it.634 *635 * Return: 0 if successful, or a negative error code on failure.636 */637int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)638{639 struct snd_kcontrol *kctl;640 641 guard(rwsem_write)(&card->controls_rwsem);642 kctl = snd_ctl_find_id(card, id);643 if (kctl == NULL)644 return -ENOENT;645 return snd_ctl_remove_locked(card, kctl);646}647EXPORT_SYMBOL(snd_ctl_remove_id);648 649/**650 * snd_ctl_remove_user_ctl - remove and release the unlocked user control651 * @file: active control handle652 * @id: the control id to remove653 *654 * Finds the control instance with the given id, removes it from the655 * card list and releases it.656 *657 * Return: 0 if successful, or a negative error code on failure.658 */659static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,660 struct snd_ctl_elem_id *id)661{662 struct snd_card *card = file->card;663 struct snd_kcontrol *kctl;664 int idx;665 666 guard(rwsem_write)(&card->controls_rwsem);667 kctl = snd_ctl_find_id(card, id);668 if (kctl == NULL)669 return -ENOENT;670 if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER))671 return -EINVAL;672 for (idx = 0; idx < kctl->count; idx++)673 if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file)674 return -EBUSY;675 return snd_ctl_remove_locked(card, kctl);676}677 678/**679 * snd_ctl_activate_id - activate/inactivate the control of the given id680 * @card: the card instance681 * @id: the control id to activate/inactivate682 * @active: non-zero to activate683 *684 * Finds the control instance with the given id, and activate or685 * inactivate the control together with notification, if changed.686 * The given ID data is filled with full information.687 *688 * Return: 0 if unchanged, 1 if changed, or a negative error code on failure.689 */690int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,691 int active)692{693 struct snd_kcontrol *kctl;694 struct snd_kcontrol_volatile *vd;695 unsigned int index_offset;696 int ret;697 698 down_write(&card->controls_rwsem);699 kctl = snd_ctl_find_id(card, id);700 if (kctl == NULL) {701 ret = -ENOENT;702 goto unlock;703 }704 index_offset = snd_ctl_get_ioff(kctl, id);705 vd = &kctl->vd[index_offset];706 ret = 0;707 if (active) {708 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))709 goto unlock;710 vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;711 } else {712 if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)713 goto unlock;714 vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;715 }716 snd_ctl_build_ioff(id, kctl, index_offset);717 downgrade_write(&card->controls_rwsem);718 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_INFO, kctl, index_offset);719 up_read(&card->controls_rwsem);720 return 1;721 722 unlock:723 up_write(&card->controls_rwsem);724 return ret;725}726EXPORT_SYMBOL_GPL(snd_ctl_activate_id);727 728/**729 * snd_ctl_rename_id - replace the id of a control on the card730 * @card: the card instance731 * @src_id: the old id732 * @dst_id: the new id733 *734 * Finds the control with the old id from the card, and replaces the735 * id with the new one.736 *737 * The function tries to keep the already assigned numid while replacing738 * the rest.739 *740 * Note that this function should be used only in the card initialization741 * phase. Calling after the card instantiation may cause issues with742 * user-space expecting persistent numids.743 *744 * Return: Zero if successful, or a negative error code on failure.745 */746int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,747 struct snd_ctl_elem_id *dst_id)748{749 struct snd_kcontrol *kctl;750 int saved_numid;751 752 guard(rwsem_write)(&card->controls_rwsem);753 kctl = snd_ctl_find_id(card, src_id);754 if (kctl == NULL)755 return -ENOENT;756 saved_numid = kctl->id.numid;757 remove_hash_entries(card, kctl);758 kctl->id = *dst_id;759 kctl->id.numid = saved_numid;760 add_hash_entries(card, kctl);761 return 0;762}763EXPORT_SYMBOL(snd_ctl_rename_id);764 765/**766 * snd_ctl_rename - rename the control on the card767 * @card: the card instance768 * @kctl: the control to rename769 * @name: the new name770 *771 * Renames the specified control on the card to the new name.772 *773 * Note that this function takes card->controls_rwsem lock internally.774 */775void snd_ctl_rename(struct snd_card *card, struct snd_kcontrol *kctl,776 const char *name)777{778 guard(rwsem_write)(&card->controls_rwsem);779 remove_hash_entries(card, kctl);780 781 if (strscpy(kctl->id.name, name, sizeof(kctl->id.name)) < 0)782 pr_warn("ALSA: Renamed control new name '%s' truncated to '%s'\n",783 name, kctl->id.name);784 785 add_hash_entries(card, kctl);786}787EXPORT_SYMBOL(snd_ctl_rename);788 789#ifndef CONFIG_SND_CTL_FAST_LOOKUP790static struct snd_kcontrol *791snd_ctl_find_numid_slow(struct snd_card *card, unsigned int numid)792{793 struct snd_kcontrol *kctl;794 795 guard(read_lock_irqsave)(&card->controls_rwlock);796 list_for_each_entry(kctl, &card->controls, list) {797 if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)798 return kctl;799 }800 return NULL;801}802#endif /* !CONFIG_SND_CTL_FAST_LOOKUP */803 804/**805 * snd_ctl_find_numid - find the control instance with the given number-id806 * @card: the card instance807 * @numid: the number-id to search808 *809 * Finds the control instance with the given number-id from the card.810 *811 * Return: The pointer of the instance if found, or %NULL if not.812 *813 * Note that this function takes card->controls_rwlock lock internally.814 */815struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card,816 unsigned int numid)817{818 if (snd_BUG_ON(!card || !numid))819 return NULL;820 821#ifdef CONFIG_SND_CTL_FAST_LOOKUP822 return xa_load(&card->ctl_numids, numid);823#else824 return snd_ctl_find_numid_slow(card, numid);825#endif826}827EXPORT_SYMBOL(snd_ctl_find_numid);828 829/**830 * snd_ctl_find_id - find the control instance with the given id831 * @card: the card instance832 * @id: the id to search833 *834 * Finds the control instance with the given id from the card.835 *836 * Return: The pointer of the instance if found, or %NULL if not.837 *838 * Note that this function takes card->controls_rwlock lock internally.839 */840struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,841 const struct snd_ctl_elem_id *id)842{843 struct snd_kcontrol *kctl;844 845 if (snd_BUG_ON(!card || !id))846 return NULL;847 848 if (id->numid != 0)849 return snd_ctl_find_numid(card, id->numid);850#ifdef CONFIG_SND_CTL_FAST_LOOKUP851 kctl = xa_load(&card->ctl_hash, get_ctl_id_hash(id));852 if (kctl && elem_id_matches(kctl, id))853 return kctl;854 if (!card->ctl_hash_collision)855 return NULL; /* we can rely on only hash table */856#endif857 /* no matching in hash table - try all as the last resort */858 guard(read_lock_irqsave)(&card->controls_rwlock);859 list_for_each_entry(kctl, &card->controls, list)860 if (elem_id_matches(kctl, id))861 return kctl;862 863 return NULL;864}865EXPORT_SYMBOL(snd_ctl_find_id);866 867static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,868 unsigned int cmd, void __user *arg)869{870 struct snd_ctl_card_info *info __free(kfree) = NULL;871 872 info = kzalloc(sizeof(*info), GFP_KERNEL);873 if (! info)874 return -ENOMEM;875 scoped_guard(rwsem_read, &snd_ioctl_rwsem) {876 info->card = card->number;877 strscpy(info->id, card->id, sizeof(info->id));878 strscpy(info->driver, card->driver, sizeof(info->driver));879 strscpy(info->name, card->shortname, sizeof(info->name));880 strscpy(info->longname, card->longname, sizeof(info->longname));881 strscpy(info->mixername, card->mixername, sizeof(info->mixername));882 strscpy(info->components, card->components, sizeof(info->components));883 }884 if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info)))885 return -EFAULT;886 return 0;887}888 889static int snd_ctl_elem_list(struct snd_card *card,890 struct snd_ctl_elem_list *list)891{892 struct snd_kcontrol *kctl;893 struct snd_ctl_elem_id id;894 unsigned int offset, space, jidx;895 896 offset = list->offset;897 space = list->space;898 899 guard(rwsem_read)(&card->controls_rwsem);900 list->count = card->controls_count;901 list->used = 0;902 if (!space)903 return 0;904 list_for_each_entry(kctl, &card->controls, list) {905 if (offset >= kctl->count) {906 offset -= kctl->count;907 continue;908 }909 for (jidx = offset; jidx < kctl->count; jidx++) {910 snd_ctl_build_ioff(&id, kctl, jidx);911 if (copy_to_user(list->pids + list->used, &id, sizeof(id)))912 return -EFAULT;913 list->used++;914 if (!--space)915 return 0;916 }917 offset = 0;918 }919 return 0;920}921 922static int snd_ctl_elem_list_user(struct snd_card *card,923 struct snd_ctl_elem_list __user *_list)924{925 struct snd_ctl_elem_list list;926 int err;927 928 if (copy_from_user(&list, _list, sizeof(list)))929 return -EFAULT;930 err = snd_ctl_elem_list(card, &list);931 if (err)932 return err;933 if (copy_to_user(_list, &list, sizeof(list)))934 return -EFAULT;935 936 return 0;937}938 939/* Check whether the given kctl info is valid */940static int snd_ctl_check_elem_info(struct snd_card *card,941 const struct snd_ctl_elem_info *info)942{943 static const unsigned int max_value_counts[] = {944 [SNDRV_CTL_ELEM_TYPE_BOOLEAN] = 128,945 [SNDRV_CTL_ELEM_TYPE_INTEGER] = 128,946 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,947 [SNDRV_CTL_ELEM_TYPE_BYTES] = 512,948 [SNDRV_CTL_ELEM_TYPE_IEC958] = 1,949 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,950 };951 952 if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||953 info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64) {954 if (card)955 dev_err(card->dev,956 "control %i:%i:%i:%s:%i: invalid type %d\n",957 info->id.iface, info->id.device,958 info->id.subdevice, info->id.name,959 info->id.index, info->type);960 return -EINVAL;961 }962 if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&963 info->value.enumerated.items == 0) {964 if (card)965 dev_err(card->dev,966 "control %i:%i:%i:%s:%i: zero enum items\n",967 info->id.iface, info->id.device,968 info->id.subdevice, info->id.name,969 info->id.index);970 return -EINVAL;971 }972 if (info->count > max_value_counts[info->type]) {973 if (card)974 dev_err(card->dev,975 "control %i:%i:%i:%s:%i: invalid count %d\n",976 info->id.iface, info->id.device,977 info->id.subdevice, info->id.name,978 info->id.index, info->count);979 return -EINVAL;980 }981 982 return 0;983}984 985/* The capacity of struct snd_ctl_elem_value.value.*/986static const unsigned int value_sizes[] = {987 [SNDRV_CTL_ELEM_TYPE_BOOLEAN] = sizeof(long),988 [SNDRV_CTL_ELEM_TYPE_INTEGER] = sizeof(long),989 [SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),990 [SNDRV_CTL_ELEM_TYPE_BYTES] = sizeof(unsigned char),991 [SNDRV_CTL_ELEM_TYPE_IEC958] = sizeof(struct snd_aes_iec958),992 [SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),993};994 995/* fill the remaining snd_ctl_elem_value data with the given pattern */996static void fill_remaining_elem_value(struct snd_ctl_elem_value *control,997 struct snd_ctl_elem_info *info,998 u32 pattern)999{1000 size_t offset = value_sizes[info->type] * info->count;1001 1002 offset = DIV_ROUND_UP(offset, sizeof(u32));1003 memset32((u32 *)control->value.bytes.data + offset, pattern,1004 sizeof(control->value) / sizeof(u32) - offset);1005}1006 1007/* check whether the given integer ctl value is valid */1008static int sanity_check_int_value(struct snd_card *card,1009 const struct snd_ctl_elem_value *control,1010 const struct snd_ctl_elem_info *info,1011 int i, bool print_error)1012{1013 long long lval, lmin, lmax, lstep;1014 u64 rem;1015 1016 switch (info->type) {1017 default:1018 case SNDRV_CTL_ELEM_TYPE_BOOLEAN:1019 lval = control->value.integer.value[i];1020 lmin = 0;1021 lmax = 1;1022 lstep = 0;1023 break;1024 case SNDRV_CTL_ELEM_TYPE_INTEGER:1025 lval = control->value.integer.value[i];1026 lmin = info->value.integer.min;1027 lmax = info->value.integer.max;1028 lstep = info->value.integer.step;1029 break;1030 case SNDRV_CTL_ELEM_TYPE_INTEGER64:1031 lval = control->value.integer64.value[i];1032 lmin = info->value.integer64.min;1033 lmax = info->value.integer64.max;1034 lstep = info->value.integer64.step;1035 break;1036 case SNDRV_CTL_ELEM_TYPE_ENUMERATED:1037 lval = control->value.enumerated.item[i];1038 lmin = 0;1039 lmax = info->value.enumerated.items - 1;1040 lstep = 0;1041 break;1042 }1043 1044 if (lval < lmin || lval > lmax) {1045 if (print_error)1046 dev_err(card->dev,1047 "control %i:%i:%i:%s:%i: value out of range %lld (%lld/%lld) at count %i\n",1048 control->id.iface, control->id.device,1049 control->id.subdevice, control->id.name,1050 control->id.index, lval, lmin, lmax, i);1051 return -EINVAL;1052 }1053 if (lstep) {1054 div64_u64_rem(lval, lstep, &rem);1055 if (rem) {1056 if (print_error)1057 dev_err(card->dev,1058 "control %i:%i:%i:%s:%i: unaligned value %lld (step %lld) at count %i\n",1059 control->id.iface, control->id.device,1060 control->id.subdevice, control->id.name,1061 control->id.index, lval, lstep, i);1062 return -EINVAL;1063 }1064 }1065 1066 return 0;1067}1068 1069/* check whether the all input values are valid for the given elem value */1070static int sanity_check_input_values(struct snd_card *card,1071 const struct snd_ctl_elem_value *control,1072 const struct snd_ctl_elem_info *info,1073 bool print_error)1074{1075 int i, ret;1076 1077 switch (info->type) {1078 case SNDRV_CTL_ELEM_TYPE_BOOLEAN:1079 case SNDRV_CTL_ELEM_TYPE_INTEGER:1080 case SNDRV_CTL_ELEM_TYPE_INTEGER64:1081 case SNDRV_CTL_ELEM_TYPE_ENUMERATED:1082 for (i = 0; i < info->count; i++) {1083 ret = sanity_check_int_value(card, control, info, i,1084 print_error);1085 if (ret < 0)1086 return ret;1087 }1088 break;1089 default:1090 break;1091 }1092 1093 return 0;1094}1095 1096/* perform sanity checks to the given snd_ctl_elem_value object */1097static int sanity_check_elem_value(struct snd_card *card,1098 const struct snd_ctl_elem_value *control,1099 const struct snd_ctl_elem_info *info,1100 u32 pattern)1101{1102 size_t offset;1103 int ret;1104 u32 *p;1105 1106 ret = sanity_check_input_values(card, control, info, true);1107 if (ret < 0)1108 return ret;1109 1110 /* check whether the remaining area kept untouched */1111 offset = value_sizes[info->type] * info->count;1112 offset = DIV_ROUND_UP(offset, sizeof(u32));1113 p = (u32 *)control->value.bytes.data + offset;1114 for (; offset < sizeof(control->value) / sizeof(u32); offset++, p++) {1115 if (*p != pattern) {1116 ret = -EINVAL;1117 break;1118 }1119 *p = 0; /* clear the checked area */1120 }1121 1122 return ret;1123}1124 1125static int __snd_ctl_elem_info(struct snd_card *card,1126 struct snd_kcontrol *kctl,1127 struct snd_ctl_elem_info *info,1128 struct snd_ctl_file *ctl)1129{1130 struct snd_kcontrol_volatile *vd;1131 unsigned int index_offset;1132 int result;1133 1134#ifdef CONFIG_SND_DEBUG1135 info->access = 0;1136#endif1137 result = kctl->info(kctl, info);1138 if (result >= 0) {1139 snd_BUG_ON(info->access);1140 index_offset = snd_ctl_get_ioff(kctl, &info->id);1141 vd = &kctl->vd[index_offset];1142 snd_ctl_build_ioff(&info->id, kctl, index_offset);1143 info->access = vd->access;1144 if (vd->owner) {1145 info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;1146 if (vd->owner == ctl)1147 info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;1148 info->owner = pid_vnr(vd->owner->pid);1149 } else {1150 info->owner = -1;1151 }1152 if (!snd_ctl_skip_validation(info) &&1153 snd_ctl_check_elem_info(card, info) < 0)1154 result = -EINVAL;1155 }1156 return result;1157}1158 1159static int snd_ctl_elem_info(struct snd_ctl_file *ctl,1160 struct snd_ctl_elem_info *info)1161{1162 struct snd_card *card = ctl->card;1163 struct snd_kcontrol *kctl;1164 1165 guard(rwsem_read)(&card->controls_rwsem);1166 kctl = snd_ctl_find_id(card, &info->id);1167 if (!kctl)1168 return -ENOENT;1169 return __snd_ctl_elem_info(card, kctl, info, ctl);1170}1171 1172static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,1173 struct snd_ctl_elem_info __user *_info)1174{1175 struct snd_card *card = ctl->card;1176 struct snd_ctl_elem_info info;1177 int result;1178 1179 if (copy_from_user(&info, _info, sizeof(info)))1180 return -EFAULT;1181 result = snd_power_ref_and_wait(card);1182 if (result)1183 return result;1184 result = snd_ctl_elem_info(ctl, &info);1185 snd_power_unref(card);1186 if (result < 0)1187 return result;1188 /* drop internal access flags */1189 info.access &= ~(SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK|1190 SNDRV_CTL_ELEM_ACCESS_LED_MASK);1191 if (copy_to_user(_info, &info, sizeof(info)))1192 return -EFAULT;1193 return result;1194}1195 1196static int snd_ctl_elem_read(struct snd_card *card,1197 struct snd_ctl_elem_value *control)1198{1199 struct snd_kcontrol *kctl;1200 struct snd_kcontrol_volatile *vd;1201 unsigned int index_offset;1202 struct snd_ctl_elem_info info;1203 const u32 pattern = 0xdeadbeef;1204 int ret;1205 1206 guard(rwsem_read)(&card->controls_rwsem);1207 kctl = snd_ctl_find_id(card, &control->id);1208 if (!kctl)1209 return -ENOENT;1210 1211 index_offset = snd_ctl_get_ioff(kctl, &control->id);1212 vd = &kctl->vd[index_offset];1213 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) || !kctl->get)1214 return -EPERM;1215 1216 snd_ctl_build_ioff(&control->id, kctl, index_offset);1217 1218#ifdef CONFIG_SND_CTL_DEBUG1219 /* info is needed only for validation */1220 memset(&info, 0, sizeof(info));1221 info.id = control->id;1222 ret = __snd_ctl_elem_info(card, kctl, &info, NULL);1223 if (ret < 0)1224 return ret;1225#endif1226 1227 if (!snd_ctl_skip_validation(&info))1228 fill_remaining_elem_value(control, &info, pattern);1229 ret = kctl->get(kctl, control);1230 if (ret < 0)1231 return ret;1232 if (!snd_ctl_skip_validation(&info) &&1233 sanity_check_elem_value(card, control, &info, pattern) < 0) {1234 dev_err(card->dev,1235 "control %i:%i:%i:%s:%i: access overflow\n",1236 control->id.iface, control->id.device,1237 control->id.subdevice, control->id.name,1238 control->id.index);1239 return -EINVAL;1240 }1241 return 0;1242}1243 1244static int snd_ctl_elem_read_user(struct snd_card *card,1245 struct snd_ctl_elem_value __user *_control)1246{1247 struct snd_ctl_elem_value *control __free(kfree) = NULL;1248 int result;1249 1250 control = memdup_user(_control, sizeof(*control));1251 if (IS_ERR(control))1252 return PTR_ERR(control);1253 1254 result = snd_power_ref_and_wait(card);1255 if (result)1256 return result;1257 result = snd_ctl_elem_read(card, control);1258 snd_power_unref(card);1259 if (result < 0)1260 return result;1261 1262 if (copy_to_user(_control, control, sizeof(*control)))1263 return -EFAULT;1264 return result;1265}1266 1267static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,1268 struct snd_ctl_elem_value *control)1269{1270 struct snd_kcontrol *kctl;1271 struct snd_kcontrol_volatile *vd;1272 unsigned int index_offset;1273 int result = 0;1274 1275 down_write(&card->controls_rwsem);1276 kctl = snd_ctl_find_id(card, &control->id);1277 if (kctl == NULL) {1278 up_write(&card->controls_rwsem);1279 return -ENOENT;1280 }1281 1282 index_offset = snd_ctl_get_ioff(kctl, &control->id);1283 vd = &kctl->vd[index_offset];1284 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||1285 (file && vd->owner && vd->owner != file)) {1286 up_write(&card->controls_rwsem);1287 return -EPERM;1288 }1289 1290 snd_ctl_build_ioff(&control->id, kctl, index_offset);1291 /* validate input values */1292 if (IS_ENABLED(CONFIG_SND_CTL_INPUT_VALIDATION)) {1293 struct snd_ctl_elem_info info;1294 1295 memset(&info, 0, sizeof(info));1296 info.id = control->id;1297 result = __snd_ctl_elem_info(card, kctl, &info, NULL);1298 if (!result)1299 result = sanity_check_input_values(card, control, &info,1300 false);1301 }1302 if (!result)1303 result = kctl->put(kctl, control);1304 if (result < 0) {1305 up_write(&card->controls_rwsem);1306 return result;1307 }1308 1309 if (result > 0) {1310 downgrade_write(&card->controls_rwsem);1311 snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_VALUE, kctl, index_offset);1312 up_read(&card->controls_rwsem);1313 } else {1314 up_write(&card->controls_rwsem);1315 }1316 1317 return 0;1318}1319 1320static int snd_ctl_elem_write_user(struct snd_ctl_file *file,1321 struct snd_ctl_elem_value __user *_control)1322{1323 struct snd_ctl_elem_value *control __free(kfree) = NULL;1324 struct snd_card *card;1325 int result;1326 1327 control = memdup_user(_control, sizeof(*control));1328 if (IS_ERR(control))1329 return PTR_ERR(control);1330 1331 card = file->card;1332 result = snd_power_ref_and_wait(card);1333 if (result < 0)1334 return result;1335 result = snd_ctl_elem_write(card, file, control);1336 snd_power_unref(card);1337 if (result < 0)1338 return result;1339 1340 if (copy_to_user(_control, control, sizeof(*control)))1341 return -EFAULT;1342 return result;1343}1344 1345static int snd_ctl_elem_lock(struct snd_ctl_file *file,1346 struct snd_ctl_elem_id __user *_id)1347{1348 struct snd_card *card = file->card;1349 struct snd_ctl_elem_id id;1350 struct snd_kcontrol *kctl;1351 struct snd_kcontrol_volatile *vd;1352 1353 if (copy_from_user(&id, _id, sizeof(id)))1354 return -EFAULT;1355 guard(rwsem_write)(&card->controls_rwsem);1356 kctl = snd_ctl_find_id(card, &id);1357 if (!kctl)1358 return -ENOENT;1359 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];1360 if (vd->owner)1361 return -EBUSY;1362 vd->owner = file;1363 return 0;1364}1365 1366static int snd_ctl_elem_unlock(struct snd_ctl_file *file,1367 struct snd_ctl_elem_id __user *_id)1368{1369 struct snd_card *card = file->card;1370 struct snd_ctl_elem_id id;1371 struct snd_kcontrol *kctl;1372 struct snd_kcontrol_volatile *vd;1373 1374 if (copy_from_user(&id, _id, sizeof(id)))1375 return -EFAULT;1376 guard(rwsem_write)(&card->controls_rwsem);1377 kctl = snd_ctl_find_id(card, &id);1378 if (!kctl)1379 return -ENOENT;1380 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];1381 if (!vd->owner)1382 return -EINVAL;1383 if (vd->owner != file)1384 return -EPERM;1385 vd->owner = NULL;1386 return 0;1387}1388 1389struct user_element {1390 struct snd_ctl_elem_info info;1391 struct snd_card *card;1392 char *elem_data; /* element data */1393 unsigned long elem_data_size; /* size of element data in bytes */1394 void *tlv_data; /* TLV data */1395 unsigned long tlv_data_size; /* TLV data size */1396 void *priv_data; /* private data (like strings for enumerated type) */1397};1398 1399// check whether the addition (in bytes) of user ctl element may overflow the limit.1400static bool check_user_elem_overflow(struct snd_card *card, ssize_t add)1401{1402 return (ssize_t)card->user_ctl_alloc_size + add > max_user_ctl_alloc_size;1403}1404 1405static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,1406 struct snd_ctl_elem_info *uinfo)1407{1408 struct user_element *ue = kcontrol->private_data;1409 unsigned int offset;1410 1411 offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);1412 *uinfo = ue->info;1413 snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);1414 1415 return 0;1416}1417 1418static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,1419 struct snd_ctl_elem_info *uinfo)1420{1421 struct user_element *ue = kcontrol->private_data;1422 const char *names;1423 unsigned int item;1424 unsigned int offset;1425 1426 item = uinfo->value.enumerated.item;1427 1428 offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);1429 *uinfo = ue->info;1430 snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);1431 1432 item = min(item, uinfo->value.enumerated.items - 1);1433 uinfo->value.enumerated.item = item;1434 1435 names = ue->priv_data;1436 for (; item > 0; --item)1437 names += strlen(names) + 1;1438 strcpy(uinfo->value.enumerated.name, names);1439 1440 return 0;1441}1442 1443static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,1444 struct snd_ctl_elem_value *ucontrol)1445{1446 struct user_element *ue = kcontrol->private_data;1447 unsigned int size = ue->elem_data_size;1448 char *src = ue->elem_data +1449 snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;1450 1451 memcpy(&ucontrol->value, src, size);1452 return 0;1453}1454 1455static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,1456 struct snd_ctl_elem_value *ucontrol)1457{1458 int err, change;1459 struct user_element *ue = kcontrol->private_data;1460 unsigned int size = ue->elem_data_size;1461 char *dst = ue->elem_data +1462 snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;1463 1464 err = sanity_check_input_values(ue->card, ucontrol, &ue->info, false);1465 if (err < 0)1466 return err;1467 1468 change = memcmp(&ucontrol->value, dst, size) != 0;1469 if (change)1470 memcpy(dst, &ucontrol->value, size);1471 return change;1472}1473 1474/* called in controls_rwsem write lock */1475static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,1476 unsigned int size)1477{1478 struct user_element *ue = kctl->private_data;1479 unsigned int *container;1480 unsigned int mask = 0;1481 int i;1482 int change;1483 1484 lockdep_assert_held_write(&ue->card->controls_rwsem);1485 1486 if (size > 1024 * 128) /* sane value */1487 return -EINVAL;1488 1489 // does the TLV size change cause overflow?1490 if (check_user_elem_overflow(ue->card, (ssize_t)(size - ue->tlv_data_size)))1491 return -ENOMEM;1492 1493 container = vmemdup_user(buf, size);1494 if (IS_ERR(container))1495 return PTR_ERR(container);1496 1497 change = ue->tlv_data_size != size;1498 if (!change)1499 change = memcmp(ue->tlv_data, container, size) != 0;1500 if (!change) {1501 kvfree(container);1502 return 0;1503 }1504 1505 if (ue->tlv_data == NULL) {1506 /* Now TLV data is available. */1507 for (i = 0; i < kctl->count; ++i)1508 kctl->vd[i].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;1509 mask = SNDRV_CTL_EVENT_MASK_INFO;1510 } else {1511 ue->card->user_ctl_alloc_size -= ue->tlv_data_size;1512 ue->tlv_data_size = 0;1513 kvfree(ue->tlv_data);1514 }1515 1516 ue->tlv_data = container;1517 ue->tlv_data_size = size;1518 // decremented at private_free.1519 ue->card->user_ctl_alloc_size += size;1520 1521 mask |= SNDRV_CTL_EVENT_MASK_TLV;1522 for (i = 0; i < kctl->count; ++i)1523 snd_ctl_notify_one(ue->card, mask, kctl, i);1524 1525 return change;1526}1527 1528static int read_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,1529 unsigned int size)1530{1531 struct user_element *ue = kctl->private_data;1532 1533 if (ue->tlv_data_size == 0 || ue->tlv_data == NULL)1534 return -ENXIO;1535 1536 if (size < ue->tlv_data_size)1537 return -ENOSPC;1538 1539 if (copy_to_user(buf, ue->tlv_data, ue->tlv_data_size))1540 return -EFAULT;1541 1542 return 0;1543}1544 1545static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kctl, int op_flag,1546 unsigned int size, unsigned int __user *buf)1547{1548 if (op_flag == SNDRV_CTL_TLV_OP_WRITE)1549 return replace_user_tlv(kctl, buf, size);1550 else1551 return read_user_tlv(kctl, buf, size);1552}1553 1554/* called in controls_rwsem write lock */1555static int snd_ctl_elem_init_enum_names(struct user_element *ue)1556{1557 char *names, *p;1558 size_t buf_len, name_len;1559 unsigned int i;1560 const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;1561 1562 lockdep_assert_held_write(&ue->card->controls_rwsem);1563 1564 buf_len = ue->info.value.enumerated.names_length;1565 if (buf_len > 64 * 1024)1566 return -EINVAL;1567 1568 if (check_user_elem_overflow(ue->card, buf_len))1569 return -ENOMEM;1570 names = vmemdup_user((const void __user *)user_ptrval, buf_len);1571 if (IS_ERR(names))1572 return PTR_ERR(names);1573 1574 /* check that there are enough valid names */1575 p = names;1576 for (i = 0; i < ue->info.value.enumerated.items; ++i) {1577 name_len = strnlen(p, buf_len);1578 if (name_len == 0 || name_len >= 64 || name_len == buf_len) {1579 kvfree(names);1580 return -EINVAL;1581 }1582 p += name_len + 1;1583 buf_len -= name_len + 1;1584 }1585 1586 ue->priv_data = names;1587 ue->info.value.enumerated.names_ptr = 0;1588 // increment the allocation size; decremented again at private_free.1589 ue->card->user_ctl_alloc_size += ue->info.value.enumerated.names_length;1590 1591 return 0;1592}1593 1594static size_t compute_user_elem_size(size_t size, unsigned int count)1595{1596 return sizeof(struct user_element) + size * count;1597}1598 1599static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)1600{1601 struct user_element *ue = kcontrol->private_data;1602 1603 // decrement the allocation size.1604 ue->card->user_ctl_alloc_size -= compute_user_elem_size(ue->elem_data_size, kcontrol->count);1605 ue->card->user_ctl_alloc_size -= ue->tlv_data_size;1606 if (ue->priv_data)1607 ue->card->user_ctl_alloc_size -= ue->info.value.enumerated.names_length;1608 1609 kvfree(ue->tlv_data);1610 kvfree(ue->priv_data);1611 kfree(ue);1612}1613 1614static int snd_ctl_elem_add(struct snd_ctl_file *file,1615 struct snd_ctl_elem_info *info, int replace)1616{1617 struct snd_card *card = file->card;1618 struct snd_kcontrol *kctl;1619 unsigned int count;1620 unsigned int access;1621 long private_size;1622 size_t alloc_size;1623 struct user_element *ue;1624 unsigned int offset;1625 int err;1626 1627 if (!*info->id.name)1628 return -EINVAL;1629 if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))1630 return -EINVAL;1631 1632 /* Delete a control to replace them if needed. */1633 if (replace) {1634 info->id.numid = 0;1635 err = snd_ctl_remove_user_ctl(file, &info->id);1636 if (err)1637 return err;1638 }1639 1640 /* Check the number of elements for this userspace control. */1641 count = info->owner;1642 if (count == 0)1643 count = 1;1644 if (count > MAX_CONTROL_COUNT)1645 return -EINVAL;1646 1647 /* Arrange access permissions if needed. */1648 access = info->access;1649 if (access == 0)1650 access = SNDRV_CTL_ELEM_ACCESS_READWRITE;1651 access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |1652 SNDRV_CTL_ELEM_ACCESS_INACTIVE |1653 SNDRV_CTL_ELEM_ACCESS_TLV_WRITE);1654 1655 /* In initial state, nothing is available as TLV container. */1656 if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)1657 access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;1658 access |= SNDRV_CTL_ELEM_ACCESS_USER;1659 1660 /*1661 * Check information and calculate the size of data specific to1662 * this userspace control.1663 */1664 /* pass NULL to card for suppressing error messages */1665 err = snd_ctl_check_elem_info(NULL, info);1666 if (err < 0)1667 return err;1668 /* user-space control doesn't allow zero-size data */1669 if (info->count < 1)1670 return -EINVAL;1671 private_size = value_sizes[info->type] * info->count;1672 alloc_size = compute_user_elem_size(private_size, count);1673 1674 guard(rwsem_write)(&card->controls_rwsem);1675 if (check_user_elem_overflow(card, alloc_size))1676 return -ENOMEM;1677 1678 /*1679 * Keep memory object for this userspace control. After passing this1680 * code block, the instance should be freed by snd_ctl_free_one().1681 *1682 * Note that these elements in this control are locked.1683 */1684 err = snd_ctl_new(&kctl, count, access, file);1685 if (err < 0)1686 return err;1687 memcpy(&kctl->id, &info->id, sizeof(kctl->id));1688 ue = kzalloc(alloc_size, GFP_KERNEL);1689 if (!ue) {1690 kfree(kctl);1691 return -ENOMEM;1692 }1693 kctl->private_data = ue;1694 kctl->private_free = snd_ctl_elem_user_free;1695 1696 // increment the allocated size; decremented again at private_free.1697 card->user_ctl_alloc_size += alloc_size;1698 1699 /* Set private data for this userspace control. */1700 ue->card = card;1701 ue->info = *info;1702 ue->info.access = 0;1703 ue->elem_data = (char *)ue + sizeof(*ue);1704 ue->elem_data_size = private_size;1705 if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {1706 err = snd_ctl_elem_init_enum_names(ue);1707 if (err < 0) {1708 snd_ctl_free_one(kctl);1709 return err;1710 }1711 }1712 1713 /* Set callback functions. */1714 if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)1715 kctl->info = snd_ctl_elem_user_enum_info;1716 else1717 kctl->info = snd_ctl_elem_user_info;1718 if (access & SNDRV_CTL_ELEM_ACCESS_READ)1719 kctl->get = snd_ctl_elem_user_get;1720 if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)1721 kctl->put = snd_ctl_elem_user_put;1722 if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)1723 kctl->tlv.c = snd_ctl_elem_user_tlv;1724 1725 /* This function manage to free the instance on failure. */1726 err = __snd_ctl_add_replace(card, kctl, CTL_ADD_EXCLUSIVE);1727 if (err < 0) {1728 snd_ctl_free_one(kctl);1729 return err;1730 }1731 offset = snd_ctl_get_ioff(kctl, &info->id);1732 snd_ctl_build_ioff(&info->id, kctl, offset);1733 /*1734 * Here we cannot fill any field for the number of elements added by1735 * this operation because there're no specific fields. The usage of1736 * 'owner' field for this purpose may cause any bugs to userspace1737 * applications because the field originally means PID of a process1738 * which locks the element.1739 */1740 return 0;1741}1742 1743static int snd_ctl_elem_add_user(struct snd_ctl_file *file,1744 struct snd_ctl_elem_info __user *_info, int replace)1745{1746 struct snd_ctl_elem_info info;1747 int err;1748 1749 if (copy_from_user(&info, _info, sizeof(info)))1750 return -EFAULT;1751 err = snd_ctl_elem_add(file, &info, replace);1752 if (err < 0)1753 return err;1754 if (copy_to_user(_info, &info, sizeof(info))) {1755 snd_ctl_remove_user_ctl(file, &info.id);1756 return -EFAULT;1757 }1758 1759 return 0;1760}1761 1762static int snd_ctl_elem_remove(struct snd_ctl_file *file,1763 struct snd_ctl_elem_id __user *_id)1764{1765 struct snd_ctl_elem_id id;1766 1767 if (copy_from_user(&id, _id, sizeof(id)))1768 return -EFAULT;1769 return snd_ctl_remove_user_ctl(file, &id);1770}1771 1772static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)1773{1774 int subscribe;1775 if (get_user(subscribe, ptr))1776 return -EFAULT;1777 if (subscribe < 0) {1778 subscribe = file->subscribed;1779 if (put_user(subscribe, ptr))1780 return -EFAULT;1781 return 0;1782 }1783 if (subscribe) {1784 file->subscribed = 1;1785 return 0;1786 } else if (file->subscribed) {1787 snd_ctl_empty_read_queue(file);1788 file->subscribed = 0;1789 }1790 return 0;1791}1792 1793static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,1794 struct snd_kcontrol *kctl,1795 struct snd_ctl_elem_id *id,1796 unsigned int __user *buf, unsigned int size)1797{1798 static const struct {1799 int op;1800 int perm;1801 } pairs[] = {1802 {SNDRV_CTL_TLV_OP_READ, SNDRV_CTL_ELEM_ACCESS_TLV_READ},1803 {SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},1804 {SNDRV_CTL_TLV_OP_CMD, SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},1805 };1806 struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];1807 int i;1808 1809 /* Check support of the request for this element. */1810 for (i = 0; i < ARRAY_SIZE(pairs); ++i) {1811 if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))1812 break;1813 }1814 if (i == ARRAY_SIZE(pairs))1815 return -ENXIO;1816 1817 if (kctl->tlv.c == NULL)1818 return -ENXIO;1819 1820 /* Write and command operations are not allowed for locked element. */1821 if (op_flag != SNDRV_CTL_TLV_OP_READ &&1822 vd->owner != NULL && vd->owner != file)1823 return -EPERM;1824 1825 return kctl->tlv.c(kctl, op_flag, size, buf);1826}1827 1828static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,1829 unsigned int __user *buf, unsigned int size)1830{1831 struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];1832 unsigned int len;1833 1834 if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ))1835 return -ENXIO;1836 1837 if (kctl->tlv.p == NULL)1838 return -ENXIO;1839 1840 len = sizeof(unsigned int) * 2 + kctl->tlv.p[1];1841 if (size < len)1842 return -ENOMEM;1843 1844 if (copy_to_user(buf, kctl->tlv.p, len))1845 return -EFAULT;1846 1847 return 0;1848}1849 1850static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,1851 struct snd_ctl_tlv __user *buf,1852 int op_flag)1853{1854 struct snd_ctl_tlv header;1855 unsigned int __user *container;1856 unsigned int container_size;1857 struct snd_kcontrol *kctl;1858 struct snd_ctl_elem_id id;1859 struct snd_kcontrol_volatile *vd;1860 1861 lockdep_assert_held(&file->card->controls_rwsem);1862 1863 if (copy_from_user(&header, buf, sizeof(header)))1864 return -EFAULT;1865 1866 /* In design of control core, numerical ID starts at 1. */1867 if (header.numid == 0)1868 return -EINVAL;1869 1870 /* At least, container should include type and length fields. */1871 if (header.length < sizeof(unsigned int) * 2)1872 return -EINVAL;1873 container_size = header.length;1874 container = buf->tlv;1875 1876 kctl = snd_ctl_find_numid(file->card, header.numid);1877 if (kctl == NULL)1878 return -ENOENT;1879 1880 /* Calculate index of the element in this set. */1881 id = kctl->id;1882 snd_ctl_build_ioff(&id, kctl, header.numid - id.numid);1883 vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];1884 1885 if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {1886 return call_tlv_handler(file, op_flag, kctl, &id, container,1887 container_size);1888 } else {1889 if (op_flag == SNDRV_CTL_TLV_OP_READ) {1890 return read_tlv_buf(kctl, &id, container,1891 container_size);1892 }1893 }1894 1895 /* Not supported. */1896 return -ENXIO;1897}1898 1899static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)1900{1901 struct snd_ctl_file *ctl;1902 struct snd_card *card;1903 struct snd_kctl_ioctl *p;1904 void __user *argp = (void __user *)arg;1905 int __user *ip = argp;1906 int err;1907 1908 ctl = file->private_data;1909 card = ctl->card;1910 if (snd_BUG_ON(!card))1911 return -ENXIO;1912 switch (cmd) {1913 case SNDRV_CTL_IOCTL_PVERSION:1914 return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;1915 case SNDRV_CTL_IOCTL_CARD_INFO:1916 return snd_ctl_card_info(card, ctl, cmd, argp);1917 case SNDRV_CTL_IOCTL_ELEM_LIST:1918 return snd_ctl_elem_list_user(card, argp);1919 case SNDRV_CTL_IOCTL_ELEM_INFO:1920 return snd_ctl_elem_info_user(ctl, argp);1921 case SNDRV_CTL_IOCTL_ELEM_READ:1922 return snd_ctl_elem_read_user(card, argp);1923 case SNDRV_CTL_IOCTL_ELEM_WRITE:1924 return snd_ctl_elem_write_user(ctl, argp);1925 case SNDRV_CTL_IOCTL_ELEM_LOCK:1926 return snd_ctl_elem_lock(ctl, argp);1927 case SNDRV_CTL_IOCTL_ELEM_UNLOCK:1928 return snd_ctl_elem_unlock(ctl, argp);1929 case SNDRV_CTL_IOCTL_ELEM_ADD:1930 return snd_ctl_elem_add_user(ctl, argp, 0);1931 case SNDRV_CTL_IOCTL_ELEM_REPLACE:1932 return snd_ctl_elem_add_user(ctl, argp, 1);1933 case SNDRV_CTL_IOCTL_ELEM_REMOVE:1934 return snd_ctl_elem_remove(ctl, argp);1935 case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:1936 return snd_ctl_subscribe_events(ctl, ip);1937 case SNDRV_CTL_IOCTL_TLV_READ:1938 err = snd_power_ref_and_wait(card);1939 if (err < 0)1940 return err;1941 scoped_guard(rwsem_read, &card->controls_rwsem)1942 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);1943 snd_power_unref(card);1944 return err;1945 case SNDRV_CTL_IOCTL_TLV_WRITE:1946 err = snd_power_ref_and_wait(card);1947 if (err < 0)1948 return err;1949 scoped_guard(rwsem_write, &card->controls_rwsem)1950 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);1951 snd_power_unref(card);1952 return err;1953 case SNDRV_CTL_IOCTL_TLV_COMMAND:1954 err = snd_power_ref_and_wait(card);1955 if (err < 0)1956 return err;1957 scoped_guard(rwsem_write, &card->controls_rwsem)1958 err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);1959 snd_power_unref(card);1960 return err;1961 case SNDRV_CTL_IOCTL_POWER:1962 return -ENOPROTOOPT;1963 case SNDRV_CTL_IOCTL_POWER_STATE:1964 return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;1965 }1966 1967 guard(rwsem_read)(&snd_ioctl_rwsem);1968 list_for_each_entry(p, &snd_control_ioctls, list) {1969 err = p->fioctl(card, ctl, cmd, arg);1970 if (err != -ENOIOCTLCMD)1971 return err;1972 }1973 dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);1974 return -ENOTTY;1975}1976 1977static ssize_t snd_ctl_read(struct file *file, char __user *buffer,1978 size_t count, loff_t * offset)1979{1980 struct snd_ctl_file *ctl;1981 int err = 0;1982 ssize_t result = 0;1983 1984 ctl = file->private_data;1985 if (snd_BUG_ON(!ctl || !ctl->card))1986 return -ENXIO;1987 if (!ctl->subscribed)1988 return -EBADFD;1989 if (count < sizeof(struct snd_ctl_event))1990 return -EINVAL;1991 spin_lock_irq(&ctl->read_lock);1992 while (count >= sizeof(struct snd_ctl_event)) {1993 struct snd_ctl_event ev;1994 struct snd_kctl_event *kev;1995 while (list_empty(&ctl->events)) {1996 wait_queue_entry_t wait;1997 if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {1998 err = -EAGAIN;1999 goto __end_lock;2000 }2001 init_waitqueue_entry(&wait, current);2002 add_wait_queue(&ctl->change_sleep, &wait);2003 set_current_state(TASK_INTERRUPTIBLE);2004 spin_unlock_irq(&ctl->read_lock);2005 schedule();2006 remove_wait_queue(&ctl->change_sleep, &wait);2007 if (ctl->card->shutdown)2008 return -ENODEV;2009 if (signal_pending(current))2010 return -ERESTARTSYS;2011 spin_lock_irq(&ctl->read_lock);2012 }2013 kev = snd_kctl_event(ctl->events.next);2014 ev.type = SNDRV_CTL_EVENT_ELEM;2015 ev.data.elem.mask = kev->mask;2016 ev.data.elem.id = kev->id;2017 list_del(&kev->list);2018 spin_unlock_irq(&ctl->read_lock);2019 kfree(kev);2020 if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {2021 err = -EFAULT;2022 goto __end;2023 }2024 spin_lock_irq(&ctl->read_lock);2025 buffer += sizeof(struct snd_ctl_event);2026 count -= sizeof(struct snd_ctl_event);2027 result += sizeof(struct snd_ctl_event);2028 }2029 __end_lock:2030 spin_unlock_irq(&ctl->read_lock);2031 __end:2032 return result > 0 ? result : err;2033}2034 2035static __poll_t snd_ctl_poll(struct file *file, poll_table * wait)2036{2037 __poll_t mask;2038 struct snd_ctl_file *ctl;2039 2040 ctl = file->private_data;2041 if (!ctl->subscribed)2042 return 0;2043 poll_wait(file, &ctl->change_sleep, wait);2044 2045 mask = 0;2046 if (!list_empty(&ctl->events))2047 mask |= EPOLLIN | EPOLLRDNORM;2048 2049 return mask;2050}2051 2052/*2053 * register the device-specific control-ioctls.2054 * called from each device manager like pcm.c, hwdep.c, etc.2055 */2056static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)2057{2058 struct snd_kctl_ioctl *pn;2059 2060 pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);2061 if (pn == NULL)2062 return -ENOMEM;2063 pn->fioctl = fcn;2064 guard(rwsem_write)(&snd_ioctl_rwsem);2065 list_add_tail(&pn->list, lists);2066 return 0;2067}2068 2069/**2070 * snd_ctl_register_ioctl - register the device-specific control-ioctls2071 * @fcn: ioctl callback function2072 *2073 * called from each device manager like pcm.c, hwdep.c, etc.2074 *2075 * Return: zero if successful, or a negative error code2076 */2077int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)2078{2079 return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);2080}2081EXPORT_SYMBOL(snd_ctl_register_ioctl);2082 2083#ifdef CONFIG_COMPAT2084/**2085 * snd_ctl_register_ioctl_compat - register the device-specific 32bit compat2086 * control-ioctls2087 * @fcn: ioctl callback function2088 *2089 * Return: zero if successful, or a negative error code2090 */2091int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)2092{2093 return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);2094}2095EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);2096#endif2097 2098/*2099 * de-register the device-specific control-ioctls.2100 */2101static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,2102 struct list_head *lists)2103{2104 struct snd_kctl_ioctl *p;2105 2106 if (snd_BUG_ON(!fcn))2107 return -EINVAL;2108 guard(rwsem_write)(&snd_ioctl_rwsem);2109 list_for_each_entry(p, lists, list) {2110 if (p->fioctl == fcn) {2111 list_del(&p->list);2112 kfree(p);2113 return 0;2114 }2115 }2116 snd_BUG();2117 return -EINVAL;2118}2119 2120/**2121 * snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls2122 * @fcn: ioctl callback function to unregister2123 *2124 * Return: zero if successful, or a negative error code2125 */2126int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)2127{2128 return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);2129}2130EXPORT_SYMBOL(snd_ctl_unregister_ioctl);2131 2132#ifdef CONFIG_COMPAT2133/**2134 * snd_ctl_unregister_ioctl_compat - de-register the device-specific compat2135 * 32bit control-ioctls2136 * @fcn: ioctl callback function to unregister2137 *2138 * Return: zero if successful, or a negative error code2139 */2140int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)2141{2142 return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);2143}2144EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);2145#endif2146 2147static int snd_ctl_fasync(int fd, struct file * file, int on)2148{2149 struct snd_ctl_file *ctl;2150 2151 ctl = file->private_data;2152 return snd_fasync_helper(fd, file, on, &ctl->fasync);2153}2154 2155/* return the preferred subdevice number if already assigned;2156 * otherwise return -12157 */2158int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)2159{2160 struct snd_ctl_file *kctl;2161 int subdevice = -1;2162 2163 guard(read_lock_irqsave)(&card->controls_rwlock);2164 list_for_each_entry(kctl, &card->ctl_files, list) {2165 if (kctl->pid == task_pid(current)) {2166 subdevice = kctl->preferred_subdevice[type];2167 if (subdevice != -1)2168 break;2169 }2170 }2171 return subdevice;2172}2173EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);2174 2175/*2176 * ioctl32 compat2177 */2178#ifdef CONFIG_COMPAT2179#include "control_compat.c"2180#else2181#define snd_ctl_ioctl_compat NULL2182#endif2183 2184/*2185 * control layers (audio LED etc.)2186 */2187 2188/**2189 * snd_ctl_request_layer - request to use the layer2190 * @module_name: Name of the kernel module (NULL == build-in)2191 *2192 * Return: zero if successful, or an error code when the module cannot be loaded2193 */2194int snd_ctl_request_layer(const char *module_name)2195{2196 struct snd_ctl_layer_ops *lops;2197 2198 if (module_name == NULL)2199 return 0;2200 scoped_guard(rwsem_read, &snd_ctl_layer_rwsem) {2201 for (lops = snd_ctl_layer; lops; lops = lops->next)2202 if (strcmp(lops->module_name, module_name) == 0)2203 return 0;2204 }2205 return request_module(module_name);2206}2207EXPORT_SYMBOL_GPL(snd_ctl_request_layer);2208 2209/**2210 * snd_ctl_register_layer - register new control layer2211 * @lops: operation structure2212 *2213 * The new layer can track all control elements and do additional2214 * operations on top (like audio LED handling).2215 */2216void snd_ctl_register_layer(struct snd_ctl_layer_ops *lops)2217{2218 struct snd_card *card;2219 int card_number;2220 2221 scoped_guard(rwsem_write, &snd_ctl_layer_rwsem) {2222 lops->next = snd_ctl_layer;2223 snd_ctl_layer = lops;2224 }2225 for (card_number = 0; card_number < SNDRV_CARDS; card_number++) {2226 card = snd_card_ref(card_number);2227 if (card) {2228 scoped_guard(rwsem_read, &card->controls_rwsem)2229 lops->lregister(card);2230 snd_card_unref(card);2231 }2232 }2233}2234EXPORT_SYMBOL_GPL(snd_ctl_register_layer);2235 2236/**2237 * snd_ctl_disconnect_layer - disconnect control layer2238 * @lops: operation structure2239 *2240 * It is expected that the information about tracked cards2241 * is freed before this call (the disconnect callback is2242 * not called here).2243 */2244void snd_ctl_disconnect_layer(struct snd_ctl_layer_ops *lops)2245{2246 struct snd_ctl_layer_ops *lops2, *prev_lops2;2247 2248 guard(rwsem_write)(&snd_ctl_layer_rwsem);2249 for (lops2 = snd_ctl_layer, prev_lops2 = NULL; lops2; lops2 = lops2->next) {2250 if (lops2 == lops) {2251 if (!prev_lops2)2252 snd_ctl_layer = lops->next;2253 else2254 prev_lops2->next = lops->next;2255 break;2256 }2257 prev_lops2 = lops2;2258 }2259}2260EXPORT_SYMBOL_GPL(snd_ctl_disconnect_layer);2261 2262/*2263 * INIT PART2264 */2265 2266static const struct file_operations snd_ctl_f_ops =2267{2268 .owner = THIS_MODULE,2269 .read = snd_ctl_read,2270 .open = snd_ctl_open,2271 .release = snd_ctl_release,2272 .poll = snd_ctl_poll,2273 .unlocked_ioctl = snd_ctl_ioctl,2274 .compat_ioctl = snd_ctl_ioctl_compat,2275 .fasync = snd_ctl_fasync,2276};2277 2278/* call lops under rwsems; called from snd_ctl_dev_*() below() */2279#define call_snd_ctl_lops(_card, _op) \2280 do { \2281 struct snd_ctl_layer_ops *lops; \2282 guard(rwsem_read)(&(_card)->controls_rwsem); \2283 guard(rwsem_read)(&snd_ctl_layer_rwsem); \2284 for (lops = snd_ctl_layer; lops; lops = lops->next) \2285 lops->_op(_card); \2286 } while (0)2287 2288/*2289 * registration of the control device2290 */2291static int snd_ctl_dev_register(struct snd_device *device)2292{2293 struct snd_card *card = device->device_data;2294 int err;2295 2296 err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,2297 &snd_ctl_f_ops, card, card->ctl_dev);2298 if (err < 0)2299 return err;2300 call_snd_ctl_lops(card, lregister);2301 return 0;2302}2303 2304/*2305 * disconnection of the control device2306 */2307static int snd_ctl_dev_disconnect(struct snd_device *device)2308{2309 struct snd_card *card = device->device_data;2310 struct snd_ctl_file *ctl;2311 2312 scoped_guard(read_lock_irqsave, &card->controls_rwlock) {2313 list_for_each_entry(ctl, &card->ctl_files, list) {2314 wake_up(&ctl->change_sleep);2315 snd_kill_fasync(ctl->fasync, SIGIO, POLL_ERR);2316 }2317 }2318 2319 call_snd_ctl_lops(card, ldisconnect);2320 return snd_unregister_device(card->ctl_dev);2321}2322 2323/*2324 * free all controls2325 */2326static int snd_ctl_dev_free(struct snd_device *device)2327{2328 struct snd_card *card = device->device_data;2329 struct snd_kcontrol *control;2330 2331 scoped_guard(rwsem_write, &card->controls_rwsem) {2332 while (!list_empty(&card->controls)) {2333 control = snd_kcontrol(card->controls.next);2334 __snd_ctl_remove(card, control, false);2335 }2336 2337#ifdef CONFIG_SND_CTL_FAST_LOOKUP2338 xa_destroy(&card->ctl_numids);2339 xa_destroy(&card->ctl_hash);2340#endif2341 }2342 put_device(card->ctl_dev);2343 return 0;2344}2345 2346/*2347 * create control core:2348 * called from init.c2349 */2350int snd_ctl_create(struct snd_card *card)2351{2352 static const struct snd_device_ops ops = {2353 .dev_free = snd_ctl_dev_free,2354 .dev_register = snd_ctl_dev_register,2355 .dev_disconnect = snd_ctl_dev_disconnect,2356 };2357 int err;2358 2359 if (snd_BUG_ON(!card))2360 return -ENXIO;2361 if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))2362 return -ENXIO;2363 2364 err = snd_device_alloc(&card->ctl_dev, card);2365 if (err < 0)2366 return err;2367 dev_set_name(card->ctl_dev, "controlC%d", card->number);2368 2369 err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);2370 if (err < 0)2371 put_device(card->ctl_dev);2372 return err;2373}2374 2375/*2376 * Frequently used control callbacks/helpers2377 */2378 2379/**2380 * snd_ctl_boolean_mono_info - Helper function for a standard boolean info2381 * callback with a mono channel2382 * @kcontrol: the kcontrol instance2383 * @uinfo: info to store2384 *2385 * This is a function that can be used as info callback for a standard2386 * boolean control with a single mono channel.2387 *2388 * Return: Zero (always successful)2389 */2390int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,2391 struct snd_ctl_elem_info *uinfo)2392{2393 uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;2394 uinfo->count = 1;2395 uinfo->value.integer.min = 0;2396 uinfo->value.integer.max = 1;2397 return 0;2398}2399EXPORT_SYMBOL(snd_ctl_boolean_mono_info);2400 2401/**2402 * snd_ctl_boolean_stereo_info - Helper function for a standard boolean info2403 * callback with stereo two channels2404 * @kcontrol: the kcontrol instance2405 * @uinfo: info to store2406 *2407 * This is a function that can be used as info callback for a standard2408 * boolean control with stereo two channels.2409 *2410 * Return: Zero (always successful)2411 */2412int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,2413 struct snd_ctl_elem_info *uinfo)2414{2415 uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;2416 uinfo->count = 2;2417 uinfo->value.integer.min = 0;2418 uinfo->value.integer.max = 1;2419 return 0;2420}2421EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);2422 2423/**2424 * snd_ctl_enum_info - fills the info structure for an enumerated control2425 * @info: the structure to be filled2426 * @channels: the number of the control's channels; often one2427 * @items: the number of control values; also the size of @names2428 * @names: an array containing the names of all control values2429 *2430 * Sets all required fields in @info to their appropriate values.2431 * If the control's accessibility is not the default (readable and writable),2432 * the caller has to fill @info->access.2433 *2434 * Return: Zero (always successful)2435 */2436int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,2437 unsigned int items, const char *const names[])2438{2439 info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;2440 info->count = channels;2441 info->value.enumerated.items = items;2442 if (!items)2443 return 0;2444 if (info->value.enumerated.item >= items)2445 info->value.enumerated.item = items - 1;2446 WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),2447 "ALSA: too long item name '%s'\n",2448 names[info->value.enumerated.item]);2449 strscpy(info->value.enumerated.name,2450 names[info->value.enumerated.item],2451 sizeof(info->value.enumerated.name));2452 return 0;2453}2454EXPORT_SYMBOL(snd_ctl_enum_info);2455