// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Routines for driver control interface
* Copyright (c) by Jaroslav Kysela <[email protected]>
*/
#include <linux/threads.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/math64.h>
#include <linux/sched/signal.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <sound/info.h>
#include <sound/control.h>
// Max allocation size for user controls.
static int max_user_ctl_alloc_size = 8 * 1024 * 1024;
module_param_named(max_user_ctl_alloc_size, max_user_ctl_alloc_size, int, 0444);
MODULE_PARM_DESC(max_user_ctl_alloc_size, "Max allocation size for user controls");
#define MAX_CONTROL_COUNT 1028
struct snd_kctl_ioctl {
struct list_head list; /* list of all ioctls */
snd_kctl_ioctl_func_t fioctl;
};
static DECLARE_RWSEM(snd_ioctl_rwsem);
static DECLARE_RWSEM(snd_ctl_layer_rwsem);
static LIST_HEAD(snd_control_ioctls);
#ifdef CONFIG_COMPAT
static LIST_HEAD(snd_control_compat_ioctls);
#endif
static struct snd_ctl_layer_ops *snd_ctl_layer;
static int snd_ctl_remove_locked(struct snd_card *card,
struct snd_kcontrol *kcontrol);
static int snd_ctl_open(struct inode *inode, struct file *file)
{
struct snd_card *card;
struct snd_ctl_file *ctl;
int i, err;
err = stream_open(inode, file);
if (err < 0)
return err;
card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
if (!card) {
err = -ENODEV;
goto __error1;
}
err = snd_card_file_add(card, file);
if (err < 0) {
err = -ENODEV;
goto __error1;
}
if (!try_module_get(card->module)) {
err = -EFAULT;
goto __error2;
}
ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
if (ctl == NULL) {
err = -ENOMEM;
goto __error;
}
INIT_LIST_HEAD(&ctl->events);
init_waitqueue_head(&ctl->change_sleep);
spin_lock_init(&ctl->read_lock);
ctl->card = card;
for (i = 0; i < SND_CTL_SUBDEV_ITEMS; i++)
ctl->preferred_subdevice[i] = -1;
ctl->pid = get_pid(task_pid(current));
file->private_data = ctl;
scoped_guard(write_lock_irqsave, &card->controls_rwlock)
list_add_tail(&ctl->list, &card->ctl_files);
snd_card_unref(card);
return 0;
__error:
module_put(card->module);
__error2:
snd_card_file_remove(card, file);
__error1:
if (card)
snd_card_unref(card);
return err;
}
static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
{
struct snd_kctl_event *cread;
guard(spinlock_irqsave)(&ctl->read_lock);
while (!list_empty(&ctl->events)) {
cread = snd_kctl_event(ctl->events.next);
list_del(&cread->list);
kfree(cread);
}
}
static int snd_ctl_release(struct inode *inode, struct file *file)
{
struct snd_card *card;
struct snd_ctl_file *ctl;
struct snd_kcontrol *control;
unsigned int idx;
ctl = file->private_data;
file->private_data = NULL;
card = ctl->card;
scoped_guard(write_lock_irqsave, &card->controls_rwlock)
list_del(&ctl->list);
scoped_guard(rwsem_write, &card->controls_rwsem) {
list_for_each_entry(control, &card->controls, list)
for (idx = 0; idx < control->count; idx++)
if (control->vd[idx].owner == ctl)
control->vd[idx].owner = NULL;
}
snd_fasync_free(ctl->fasync);
snd_ctl_empty_read_queue(ctl);
put_pid(ctl->pid);
kfree(ctl);
module_put(card->module);
snd_card_file_remove(card, file);
return 0;
}
/**
* snd_ctl_notify - Send notification to user-space for a control change
* @card: the card to send notification
* @mask: the event mask, SNDRV_CTL_EVENT_*
* @id: the ctl element id to send notification
*
* This function adds an event record with the given id and mask, appends
* to the list and wakes up the user-space for notification. This can be
* called in the atomic context.
*/
void snd_ctl_notify(struct snd_card *card, unsigned int mask,
struct snd_ctl_elem_id *id)
{
struct snd_ctl_file *ctl;
struct snd_kctl_event *ev;
if (snd_BUG_ON(!card || !id))
return;
if (card->shutdown)
return;
guard(read_lock_irqsave)(&card->controls_rwlock);
#if IS_ENABLED(CONFIG_SND_MIXER_OSS)
card->mixer_oss_change_count++;
#endif
list_for_each_entry(ctl, &card->ctl_files, list) {
if (!ctl->subscribed)
continue;
scoped_guard(spinlock, &ctl->read_lock) {
list_for_each_entry(ev, &ctl->events, list) {
if (ev->id.numid == id->numid) {
ev->mask |= mask;
goto _found;
}
}
ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
if (ev) {
ev->id = *id;
ev->mask = mask;
list_add_tail(&ev->list, &ctl->events);
} else {
dev_err(card->dev, "No memory available to allocate event\n");
}
_found:
wake_up(&ctl->change_sleep);
}
snd_kill_fasync(ctl->fasync, SIGIO, POLL_IN);
}
}
EXPORT_SYMBOL(snd_ctl_notify);
/**
* snd_ctl_notify_one - Send notification to user-space for a control change
* @card: the card to send notification
* @mask: the event mask, SNDRV_CTL_EVENT_*
* @kctl: the pointer with the control instance
* @ioff: the additional offset to the control index
*
* This function calls snd_ctl_notify() and does additional jobs
* like LED state changes.
*/
void snd_ctl_notify_one(struct snd_card *card, unsigned int mask,
struct snd_kcontrol *kctl, unsigned int ioff)
{
struct snd_ctl_elem_id id = kctl->id;
struct snd_ctl_layer_ops *lops;
id.index += ioff;
id.numid += ioff;
snd_ctl_notify(card, mask, &id);
guard(rwsem_read)(&snd_ctl_layer_rwsem);
for (lops = snd_ctl_layer; lops; lops = lops->next)
lops->lnotify(card, mask, kctl, ioff);
}
EXPORT_SYMBOL(snd_ctl_notify_one);
/**
* snd_ctl_new - create a new control instance with some elements
* @kctl: the pointer to store new control instance
* @count: the number of elements in this control
* @access: the default access flags for elements in this control
* @file: given when locking these elements
*
* Allocates a memory object for a new control instance. The instance has
* elements as many as the given number (@count). Each element has given
* access permissions (@access). Each element is locked when @file is given.
*
* Return: 0 on success, error code on failure
*/
static int snd_ctl_new(struct snd_kcontrol **kctl, unsigned int count,
unsigned int access, struct snd_ctl_file *file)
{
unsigned int idx;
if (count == 0 || count > MAX_CONTROL_COUNT)
return -EINVAL;
*kctl = kzalloc(struct_size(*kctl, vd, count), GFP_KERNEL);
if (!*kctl)
return -ENOMEM;
(*kctl)->count = count;
for (idx = 0; idx < count; idx++) {
(*kctl)->vd[idx].access = access;
(*kctl)->vd[idx].owner = file;
}
return 0;
}
/**
* snd_ctl_new1 - create a control instance from the template
* @ncontrol: the initialization record
* @private_data: the private data to set
*
* Allocates a new struct snd_kcontrol instance and initialize from the given
* template. When the access field of ncontrol is 0, it's assumed as
* READWRITE access. When the count field is 0, it's assumes as one.
*
* Return: The pointer of the newly generated instance, or %NULL on failure.
*/
struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
void *private_data)
{
struct snd_kcontrol *kctl;
unsigned int count;
unsigned int access;
int err;
if (snd_BUG_ON(!ncontrol || !ncontrol->info))
return NULL;
count = ncontrol->count;
if (count == 0)
count = 1;
access = ncontrol->access;
if (access == 0)
access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
SNDRV_CTL_ELEM_ACCESS_VOLATILE |
SNDRV_CTL_ELEM_ACCESS_INACTIVE |
SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE |
SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND |
SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK |
SNDRV_CTL_ELEM_ACCESS_LED_MASK |
SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK);
err = snd_ctl_new(&kctl, count, access, NULL);
if (err < 0)
return NULL;
/* The 'numid' member is decided when calling snd_ctl_add(). */
kctl->id.iface = ncontrol->iface;
kctl->id.device = ncontrol->device;
kctl->id.subdevice = ncontrol->subdevice;
if (ncontrol->name) {
strscpy(kctl->id.name, ncontrol->name, sizeof(kctl->id.name));
if (strcmp(ncontrol->name, kctl->id.name) != 0)
pr_warn("ALSA: Control name '%s' truncated to '%s'\n",
ncontrol->name, kctl->id.name);
}
kctl->id.index = ncontrol->index;
kctl->info = ncontrol->info;
kctl->get = ncontrol->get;
kctl->put = ncontrol->put;
kctl->tlv.p = ncontrol->tlv.p;
kctl->private_value = ncontrol->private_value;
kctl->private_data = private_data;
return kctl;
}
EXPORT_SYMBOL(snd_ctl_new1);
/**
* snd_ctl_free_one - release the control instance
* @kcontrol: the control instance
*
* Releases the control instance created via snd_ctl_new()
* or snd_ctl_new1().
* Don't call this after the control was added to the card.
*/
void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
{
if (kcontrol) {
if (kcontrol->private_free)
kcontrol->private_free(kcontrol);
kfree(kcontrol);
}
}
EXPORT_SYMBOL(snd_ctl_free_one);
static bool snd_ctl_remove_numid_conflict(struct snd_card *card,
unsigned int count)
{
struct snd_kcontrol *kctl;
/* Make sure that the ids assigned to the control do not wrap around */
if (card->last_numid >= UINT_MAX - count)
card->last_numid = 0;
list_for_each_entry(kctl, &card->controls, list) {
if (kctl->id.numid < card->last_numid + 1 + count &&
kctl->id.numid + kctl->count > card->last_numid + 1) {
card->last_numid = kctl->id.numid + kctl->count - 1;
return true;
}
}
return false;
}
static int snd_ctl_find_hole(struct snd_card *card, unsigned int count)
{
unsigned int iter = 100000;
while (snd_ctl_remove_numid_conflict(card, count)) {
if (--iter == 0) {
/* this situation is very unlikely */
dev_err(card->dev, "unable to allocate new control numid\n");
return -ENOMEM;
}
}
return 0;
}
/* check whether the given id is contained in the given kctl */
static bool elem_id_matches(const struct snd_kcontrol *kctl,
const struct snd_ctl_elem_id *id)
{
return kctl->id.iface == id->iface &&
kctl->id.device == id->device &&
kctl->id.subdevice == id->subdevice &&
!strncmp(kctl->id.name, id->name, sizeof(kctl->id.name)) &&
kctl->id.index <= id->index &&
kctl->id.index + kctl->count > id->index;
}
#ifdef CONFIG_SND_CTL_FAST_LOOKUP
/* Compute a hash key for the corresponding ctl id
* It's for the name lookup, hence the numid is excluded.
* The hash key is bound in LONG_MAX to be used for Xarray key.
*/
#define MULTIPLIER 37
static unsigned long get_ctl_id_hash(const struct snd_ctl_elem_id *id)
{
int i;
unsigned long h;
h = id->iface;
h = MULTIPLIER * h + id->device;
h = MULTIPLIER * h + id->subdevice;
for (i = 0; i < SNDRV_CTL_ELEM_ID_NAME_MAXLEN && id->name[i]; i++)
h = MULTIPLIER * h + id->name[i];
h = MULTIPLIER * h + id->index;
h &= LONG_MAX;
return h;
}
/* add hash entries to numid and ctl xarray tables */
static void add_hash_entries(struct snd_card *card,
struct snd_kcontrol *kcontrol)
{
struct snd_ctl_elem_id id = kcontrol->id;
int i;
xa_store_range(&card->ctl_numids, kcontrol->id.numid,
kcontrol->id.numid + kcontrol->count - 1,
kcontrol, GFP_KERNEL);
for (i = 0; i < kcontrol->count; i++) {
id.index = kcontrol->id.index + i;
if (xa_insert(&card->ctl_hash, get_ctl_id_hash(&id),
kcontrol, GFP_KERNEL)) {
/* skip hash for this entry, noting we had collision */
card->ctl_hash_collision = true;
dev_dbg(card->dev, "ctl_hash collision %d:%s:%d\n",
id.iface, id.name, id.index);
}
}
}
/* remove hash entries that have been added */
static void remove_hash_entries(struct snd_card *card,
struct snd_kcontrol *kcontrol)
{
struct snd_ctl_elem_id id = kcontrol->id;
struct snd_kcontrol *matched;
unsigned long h;
int i;
for (i = 0; i < kcontrol->count; i++) {
xa_erase(&card->ctl_numids, id.numid);
h = get_ctl_id_hash(&id);
matched = xa_load(&card->ctl_hash, h);
if (matched && (matched == kcontrol ||
elem_id_matches(matched, &id)))
xa_erase(&card->ctl_hash, h);
id.index++;
id.numid++;
}
}
#else /* CONFIG_SND_CTL_FAST_LOOKUP */
static inline void add_hash_entries(struct snd_card *card,
struct snd_kcontrol *kcontrol)
{
}
static inline void remove_hash_entries(struct snd_card *card,
struct snd_kcontrol *kcontrol)
{
}
#endif /* CONFIG_SND_CTL_FAST_LOOKUP */
enum snd_ctl_add_mode {
CTL_ADD_EXCLUSIVE, CTL_REPLACE, CTL_ADD_ON_REPLACE,
};
/* add/replace a new kcontrol object; call with card->controls_rwsem locked */
static int __snd_ctl_add_replace(struct snd_card *card,
struct snd_kcontrol *kcontrol,
enum snd_ctl_add_mode mode)
{
struct snd_ctl_elem_id id;
unsigned int idx;
struct snd_kcontrol *old;
int err;
lockdep_assert_held_write(&card->controls_rwsem);
id = kcontrol->id;
if (id.index > UINT_MAX - kcontrol->count)
return -EINVAL;
old = snd_ctl_find_id(card, &id);
if (!old) {
if (mode == CTL_REPLACE)
return -EINVAL;
} else {
if (mode == CTL_ADD_EXCLUSIVE) {
dev_err(card->dev,
"control %i:%i:%i:%s:%i is already present\n",
id.iface, id.device, id.subdevice, id.name,
id.index);
return -EBUSY;
}
err = snd_ctl_remove_locked(card, old);
if (err < 0)
return err;
}
if (snd_ctl_find_hole(card, kcontrol->count) < 0)
return -ENOMEM;
scoped_guard(write_lock_irq, &card->controls_rwlock) {
list_add_tail(&kcontrol->list, &card->controls);
card->controls_count += kcontrol->count;
kcontrol->id.numid = card->last_numid + 1;
card->last_numid += kcontrol->count;
}
add_hash_entries(card, kcontrol);
for (idx = 0; idx < kcontrol->count; idx++)
snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_ADD, kcontrol, idx);
return 0;
}
static int snd_ctl_add_replace(struct snd_card *card,
struct snd_kcontrol *kcontrol,
enum snd_ctl_add_mode mode)
{
int err = -EINVAL;
if (! kcontrol)
return err;
if (snd_BUG_ON(!card || !kcontrol->info))
goto error;
scoped_guard(rwsem_write, &card->controls_rwsem)
err = __snd_ctl_add_replace(card, kcontrol, mode);
if (err < 0)
goto error;
return 0;
error:
snd_ctl_free_one(kcontrol);
return err;
}
/**
* snd_ctl_add - add the control instance to the card
* @card: the card instance
* @kcontrol: the control instance to add
*
* Adds the control instance created via snd_ctl_new() or
* snd_ctl_new1() to the given card. Assigns also an unique
* numid used for fast search.
*
* It frees automatically the control which cannot be added.
*
* Return: Zero if successful, or a negative error code on failure.
*
*/
int snd_ctl_add(struct snd_card *card, struct snd_kcontrol *kcontrol)
{
return snd_ctl_add_replace(card, kcontrol, CTL_ADD_EXCLUSIVE);
}
EXPORT_SYMBOL(snd_ctl_add);
/**
* snd_ctl_replace - replace the control instance of the card
* @card: the card instance
* @kcontrol: the control instance to replace
* @add_on_replace: add the control if not already added
*
* Replaces the given control. If the given control does not exist
* and the add_on_replace flag is set, the control is added. If the
* control exists, it is destroyed first.
*
* It frees automatically the control which cannot be added or replaced.
*
* Return: Zero if successful, or a negative error code on failure.
*/
int snd_ctl_replace(struct snd_card *card, struct snd_kcontrol *kcontrol,
bool add_on_replace)
{
return snd_ctl_add_replace(card, kcontrol,
add_on_replace ? CTL_ADD_ON_REPLACE : CTL_REPLACE);
}
EXPORT_SYMBOL(snd_ctl_replace);
static int __snd_ctl_remove(struct snd_card *card,
struct snd_kcontrol *kcontrol,
bool remove_hash)
{
unsigned int idx;
lockdep_assert_held_write(&card->controls_rwsem);
if (snd_BUG_ON(!card || !kcontrol))
return -EINVAL;
if (remove_hash)
remove_hash_entries(card, kcontrol);
scoped_guard(write_lock_irq, &card->controls_rwlock) {
list_del(&kcontrol->list);
card->controls_count -= kcontrol->count;
}
for (idx = 0; idx < kcontrol->count; idx++)
snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_REMOVE, kcontrol, idx);
snd_ctl_free_one(kcontrol);
return 0;
}
static inline int snd_ctl_remove_locked(struct snd_card *card,
struct snd_kcontrol *kcontrol)
{
return __snd_ctl_remove(card, kcontrol, true);
}
/**
* snd_ctl_remove - remove the control from the card and release it
* @card: the card instance
* @kcontrol: the control instance to remove
*
* Removes the control from the card and then releases the instance.
* You don't need to call snd_ctl_free_one().
* Passing NULL to @kcontrol argument is allowed as noop.
*
* Return: 0 if successful, or a negative error code on failure.
*
* Note that this function takes card->controls_rwsem lock internally.
*/
int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol)
{
if (!kcontrol)
return 0;
guard(rwsem_write)(&card->controls_rwsem);
return snd_ctl_remove_locked(card, kcontrol);
}
EXPORT_SYMBOL(snd_ctl_remove);
/**
* snd_ctl_remove_id - remove the control of the given id and release it
* @card: the card instance
* @id: the control id to remove
*
* Finds the control instance with the given id, removes it from the
* card list and releases it.
*
* Return: 0 if successful, or a negative error code on failure.
*/
int snd_ctl_remove_id(struct snd_card *card, struct snd_ctl_elem_id *id)
{
struct snd_kcontrol *kctl;
guard(rwsem_write)(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, id);
if (kctl == NULL)
return -ENOENT;
return snd_ctl_remove_locked(card, kctl);
}
EXPORT_SYMBOL(snd_ctl_remove_id);
/**
* snd_ctl_remove_user_ctl - remove and release the unlocked user control
* @file: active control handle
* @id: the control id to remove
*
* Finds the control instance with the given id, removes it from the
* card list and releases it.
*
* Return: 0 if successful, or a negative error code on failure.
*/
static int snd_ctl_remove_user_ctl(struct snd_ctl_file * file,
struct snd_ctl_elem_id *id)
{
struct snd_card *card = file->card;
struct snd_kcontrol *kctl;
int idx;
guard(rwsem_write)(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, id);
if (kctl == NULL)
return -ENOENT;
if (!(kctl->vd[0].access & SNDRV_CTL_ELEM_ACCESS_USER))
return -EINVAL;
for (idx = 0; idx < kctl->count; idx++)
if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file)
return -EBUSY;
return snd_ctl_remove_locked(card, kctl);
}
/**
* snd_ctl_activate_id - activate/inactivate the control of the given id
* @card: the card instance
* @id: the control id to activate/inactivate
* @active: non-zero to activate
*
* Finds the control instance with the given id, and activate or
* inactivate the control together with notification, if changed.
* The given ID data is filled with full information.
*
* Return: 0 if unchanged, 1 if changed, or a negative error code on failure.
*/
int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id,
int active)
{
struct snd_kcontrol *kctl;
struct snd_kcontrol_volatile *vd;
unsigned int index_offset;
int ret;
down_write(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, id);
if (kctl == NULL) {
ret = -ENOENT;
goto unlock;
}
index_offset = snd_ctl_get_ioff(kctl, id);
vd = &kctl->vd[index_offset];
ret = 0;
if (active) {
if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE))
goto unlock;
vd->access &= ~SNDRV_CTL_ELEM_ACCESS_INACTIVE;
} else {
if (vd->access & SNDRV_CTL_ELEM_ACCESS_INACTIVE)
goto unlock;
vd->access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE;
}
snd_ctl_build_ioff(id, kctl, index_offset);
downgrade_write(&card->controls_rwsem);
snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_INFO, kctl, index_offset);
up_read(&card->controls_rwsem);
return 1;
unlock:
up_write(&card->controls_rwsem);
return ret;
}
EXPORT_SYMBOL_GPL(snd_ctl_activate_id);
/**
* snd_ctl_rename_id - replace the id of a control on the card
* @card: the card instance
* @src_id: the old id
* @dst_id: the new id
*
* Finds the control with the old id from the card, and replaces the
* id with the new one.
*
* The function tries to keep the already assigned numid while replacing
* the rest.
*
* Note that this function should be used only in the card initialization
* phase. Calling after the card instantiation may cause issues with
* user-space expecting persistent numids.
*
* Return: Zero if successful, or a negative error code on failure.
*/
int snd_ctl_rename_id(struct snd_card *card, struct snd_ctl_elem_id *src_id,
struct snd_ctl_elem_id *dst_id)
{
struct snd_kcontrol *kctl;
int saved_numid;
guard(rwsem_write)(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, src_id);
if (kctl == NULL)
return -ENOENT;
saved_numid = kctl->id.numid;
remove_hash_entries(card, kctl);
kctl->id = *dst_id;
kctl->id.numid = saved_numid;
add_hash_entries(card, kctl);
return 0;
}
EXPORT_SYMBOL(snd_ctl_rename_id);
/**
* snd_ctl_rename - rename the control on the card
* @card: the card instance
* @kctl: the control to rename
* @name: the new name
*
* Renames the specified control on the card to the new name.
*
* Note that this function takes card->controls_rwsem lock internally.
*/
void snd_ctl_rename(struct snd_card *card, struct snd_kcontrol *kctl,
const char *name)
{
guard(rwsem_write)(&card->controls_rwsem);
remove_hash_entries(card, kctl);
if (strscpy(kctl->id.name, name, sizeof(kctl->id.name)) < 0)
pr_warn("ALSA: Renamed control new name '%s' truncated to '%s'\n",
name, kctl->id.name);
add_hash_entries(card, kctl);
}
EXPORT_SYMBOL(snd_ctl_rename);
#ifndef CONFIG_SND_CTL_FAST_LOOKUP
static struct snd_kcontrol *
snd_ctl_find_numid_slow(struct snd_card *card, unsigned int numid)
{
struct snd_kcontrol *kctl;
guard(read_lock_irqsave)(&card->controls_rwlock);
list_for_each_entry(kctl, &card->controls, list) {
if (kctl->id.numid <= numid && kctl->id.numid + kctl->count > numid)
return kctl;
}
return NULL;
}
#endif /* !CONFIG_SND_CTL_FAST_LOOKUP */
/**
* snd_ctl_find_numid - find the control instance with the given number-id
* @card: the card instance
* @numid: the number-id to search
*
* Finds the control instance with the given number-id from the card.
*
* Return: The pointer of the instance if found, or %NULL if not.
*
* Note that this function takes card->controls_rwlock lock internally.
*/
struct snd_kcontrol *snd_ctl_find_numid(struct snd_card *card,
unsigned int numid)
{
if (snd_BUG_ON(!card || !numid))
return NULL;
#ifdef CONFIG_SND_CTL_FAST_LOOKUP
return xa_load(&card->ctl_numids, numid);
#else
return snd_ctl_find_numid_slow(card, numid);
#endif
}
EXPORT_SYMBOL(snd_ctl_find_numid);
/**
* snd_ctl_find_id - find the control instance with the given id
* @card: the card instance
* @id: the id to search
*
* Finds the control instance with the given id from the card.
*
* Return: The pointer of the instance if found, or %NULL if not.
*
* Note that this function takes card->controls_rwlock lock internally.
*/
struct snd_kcontrol *snd_ctl_find_id(struct snd_card *card,
const struct snd_ctl_elem_id *id)
{
struct snd_kcontrol *kctl;
if (snd_BUG_ON(!card || !id))
return NULL;
if (id->numid != 0)
return snd_ctl_find_numid(card, id->numid);
#ifdef CONFIG_SND_CTL_FAST_LOOKUP
kctl = xa_load(&card->ctl_hash, get_ctl_id_hash(id));
if (kctl && elem_id_matches(kctl, id))
return kctl;
if (!card->ctl_hash_collision)
return NULL; /* we can rely on only hash table */
#endif
/* no matching in hash table - try all as the last resort */
guard(read_lock_irqsave)(&card->controls_rwlock);
list_for_each_entry(kctl, &card->controls, list)
if (elem_id_matches(kctl, id))
return kctl;
return NULL;
}
EXPORT_SYMBOL(snd_ctl_find_id);
static int snd_ctl_card_info(struct snd_card *card, struct snd_ctl_file * ctl,
unsigned int cmd, void __user *arg)
{
struct snd_ctl_card_info *info __free(kfree) = NULL;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (! info)
return -ENOMEM;
scoped_guard(rwsem_read, &snd_ioctl_rwsem) {
info->card = card->number;
strscpy(info->id, card->id, sizeof(info->id));
strscpy(info->driver, card->driver, sizeof(info->driver));
strscpy(info->name, card->shortname, sizeof(info->name));
strscpy(info->longname, card->longname, sizeof(info->longname));
strscpy(info->mixername, card->mixername, sizeof(info->mixername));
strscpy(info->components, card->components, sizeof(info->components));
}
if (copy_to_user(arg, info, sizeof(struct snd_ctl_card_info)))
return -EFAULT;
return 0;
}
static int snd_ctl_elem_list(struct snd_card *card,
struct snd_ctl_elem_list *list)
{
struct snd_kcontrol *kctl;
struct snd_ctl_elem_id id;
unsigned int offset, space, jidx;
offset = list->offset;
space = list->space;
guard(rwsem_read)(&card->controls_rwsem);
list->count = card->controls_count;
list->used = 0;
if (!space)
return 0;
list_for_each_entry(kctl, &card->controls, list) {
if (offset >= kctl->count) {
offset -= kctl->count;
continue;
}
for (jidx = offset; jidx < kctl->count; jidx++) {
snd_ctl_build_ioff(&id, kctl, jidx);
if (copy_to_user(list->pids + list->used, &id, sizeof(id)))
return -EFAULT;
list->used++;
if (!--space)
return 0;
}
offset = 0;
}
return 0;
}
static int snd_ctl_elem_list_user(struct snd_card *card,
struct snd_ctl_elem_list __user *_list)
{
struct snd_ctl_elem_list list;
int err;
if (copy_from_user(&list, _list, sizeof(list)))
return -EFAULT;
err = snd_ctl_elem_list(card, &list);
if (err)
return err;
if (copy_to_user(_list, &list, sizeof(list)))
return -EFAULT;
return 0;
}
/* Check whether the given kctl info is valid */
static int snd_ctl_check_elem_info(struct snd_card *card,
const struct snd_ctl_elem_info *info)
{
static const unsigned int max_value_counts[] = {
[SNDRV_CTL_ELEM_TYPE_BOOLEAN] = 128,
[SNDRV_CTL_ELEM_TYPE_INTEGER] = 128,
[SNDRV_CTL_ELEM_TYPE_ENUMERATED] = 128,
[SNDRV_CTL_ELEM_TYPE_BYTES] = 512,
[SNDRV_CTL_ELEM_TYPE_IEC958] = 1,
[SNDRV_CTL_ELEM_TYPE_INTEGER64] = 64,
};
if (info->type < SNDRV_CTL_ELEM_TYPE_BOOLEAN ||
info->type > SNDRV_CTL_ELEM_TYPE_INTEGER64) {
if (card)
dev_err(card->dev,
"control %i:%i:%i:%s:%i: invalid type %d\n",
info->id.iface, info->id.device,
info->id.subdevice, info->id.name,
info->id.index, info->type);
return -EINVAL;
}
if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED &&
info->value.enumerated.items == 0) {
if (card)
dev_err(card->dev,
"control %i:%i:%i:%s:%i: zero enum items\n",
info->id.iface, info->id.device,
info->id.subdevice, info->id.name,
info->id.index);
return -EINVAL;
}
if (info->count > max_value_counts[info->type]) {
if (card)
dev_err(card->dev,
"control %i:%i:%i:%s:%i: invalid count %d\n",
info->id.iface, info->id.device,
info->id.subdevice, info->id.name,
info->id.index, info->count);
return -EINVAL;
}
return 0;
}
/* The capacity of struct snd_ctl_elem_value.value.*/
static const unsigned int value_sizes[] = {
[SNDRV_CTL_ELEM_TYPE_BOOLEAN] = sizeof(long),
[SNDRV_CTL_ELEM_TYPE_INTEGER] = sizeof(long),
[SNDRV_CTL_ELEM_TYPE_ENUMERATED] = sizeof(unsigned int),
[SNDRV_CTL_ELEM_TYPE_BYTES] = sizeof(unsigned char),
[SNDRV_CTL_ELEM_TYPE_IEC958] = sizeof(struct snd_aes_iec958),
[SNDRV_CTL_ELEM_TYPE_INTEGER64] = sizeof(long long),
};
/* fill the remaining snd_ctl_elem_value data with the given pattern */
static void fill_remaining_elem_value(struct snd_ctl_elem_value *control,
struct snd_ctl_elem_info *info,
u32 pattern)
{
size_t offset = value_sizes[info->type] * info->count;
offset = DIV_ROUND_UP(offset, sizeof(u32));
memset32((u32 *)control->value.bytes.data + offset, pattern,
sizeof(control->value) / sizeof(u32) - offset);
}
/* check whether the given integer ctl value is valid */
static int sanity_check_int_value(struct snd_card *card,
const struct snd_ctl_elem_value *control,
const struct snd_ctl_elem_info *info,
int i, bool print_error)
{
long long lval, lmin, lmax, lstep;
u64 rem;
switch (info->type) {
default:
case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
lval = control->value.integer.value[i];
lmin = 0;
lmax = 1;
lstep = 0;
break;
case SNDRV_CTL_ELEM_TYPE_INTEGER:
lval = control->value.integer.value[i];
lmin = info->value.integer.min;
lmax = info->value.integer.max;
lstep = info->value.integer.step;
break;
case SNDRV_CTL_ELEM_TYPE_INTEGER64:
lval = control->value.integer64.value[i];
lmin = info->value.integer64.min;
lmax = info->value.integer64.max;
lstep = info->value.integer64.step;
break;
case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
lval = control->value.enumerated.item[i];
lmin = 0;
lmax = info->value.enumerated.items - 1;
lstep = 0;
break;
}
if (lval < lmin || lval > lmax) {
if (print_error)
dev_err(card->dev,
"control %i:%i:%i:%s:%i: value out of range %lld (%lld/%lld) at count %i\n",
control->id.iface, control->id.device,
control->id.subdevice, control->id.name,
control->id.index, lval, lmin, lmax, i);
return -EINVAL;
}
if (lstep) {
div64_u64_rem(lval, lstep, &rem);
if (rem) {
if (print_error)
dev_err(card->dev,
"control %i:%i:%i:%s:%i: unaligned value %lld (step %lld) at count %i\n",
control->id.iface, control->id.device,
control->id.subdevice, control->id.name,
control->id.index, lval, lstep, i);
return -EINVAL;
}
}
return 0;
}
/* check whether the all input values are valid for the given elem value */
static int sanity_check_input_values(struct snd_card *card,
const struct snd_ctl_elem_value *control,
const struct snd_ctl_elem_info *info,
bool print_error)
{
int i, ret;
switch (info->type) {
case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
case SNDRV_CTL_ELEM_TYPE_INTEGER:
case SNDRV_CTL_ELEM_TYPE_INTEGER64:
case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
for (i = 0; i < info->count; i++) {
ret = sanity_check_int_value(card, control, info, i,
print_error);
if (ret < 0)
return ret;
}
break;
default:
break;
}
return 0;
}
/* perform sanity checks to the given snd_ctl_elem_value object */
static int sanity_check_elem_value(struct snd_card *card,
const struct snd_ctl_elem_value *control,
const struct snd_ctl_elem_info *info,
u32 pattern)
{
size_t offset;
int ret;
u32 *p;
ret = sanity_check_input_values(card, control, info, true);
if (ret < 0)
return ret;
/* check whether the remaining area kept untouched */
offset = value_sizes[info->type] * info->count;
offset = DIV_ROUND_UP(offset, sizeof(u32));
p = (u32 *)control->value.bytes.data + offset;
for (; offset < sizeof(control->value) / sizeof(u32); offset++, p++) {
if (*p != pattern) {
ret = -EINVAL;
break;
}
*p = 0; /* clear the checked area */
}
return ret;
}
static int __snd_ctl_elem_info(struct snd_card *card,
struct snd_kcontrol *kctl,
struct snd_ctl_elem_info *info,
struct snd_ctl_file *ctl)
{
struct snd_kcontrol_volatile *vd;
unsigned int index_offset;
int result;
#ifdef CONFIG_SND_DEBUG
info->access = 0;
#endif
result = kctl->info(kctl, info);
if (result >= 0) {
snd_BUG_ON(info->access);
index_offset = snd_ctl_get_ioff(kctl, &info->id);
vd = &kctl->vd[index_offset];
snd_ctl_build_ioff(&info->id, kctl, index_offset);
info->access = vd->access;
if (vd->owner) {
info->access |= SNDRV_CTL_ELEM_ACCESS_LOCK;
if (vd->owner == ctl)
info->access |= SNDRV_CTL_ELEM_ACCESS_OWNER;
info->owner = pid_vnr(vd->owner->pid);
} else {
info->owner = -1;
}
if (!snd_ctl_skip_validation(info) &&
snd_ctl_check_elem_info(card, info) < 0)
result = -EINVAL;
}
return result;
}
static int snd_ctl_elem_info(struct snd_ctl_file *ctl,
struct snd_ctl_elem_info *info)
{
struct snd_card *card = ctl->card;
struct snd_kcontrol *kctl;
guard(rwsem_read)(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, &info->id);
if (!kctl)
return -ENOENT;
return __snd_ctl_elem_info(card, kctl, info, ctl);
}
static int snd_ctl_elem_info_user(struct snd_ctl_file *ctl,
struct snd_ctl_elem_info __user *_info)
{
struct snd_card *card = ctl->card;
struct snd_ctl_elem_info info;
int result;
if (copy_from_user(&info, _info, sizeof(info)))
return -EFAULT;
result = snd_power_ref_and_wait(card);
if (result)
return result;
result = snd_ctl_elem_info(ctl, &info);
snd_power_unref(card);
if (result < 0)
return result;
/* drop internal access flags */
info.access &= ~(SNDRV_CTL_ELEM_ACCESS_SKIP_CHECK|
SNDRV_CTL_ELEM_ACCESS_LED_MASK);
if (copy_to_user(_info, &info, sizeof(info)))
return -EFAULT;
return result;
}
static int snd_ctl_elem_read(struct snd_card *card,
struct snd_ctl_elem_value *control)
{
struct snd_kcontrol *kctl;
struct snd_kcontrol_volatile *vd;
unsigned int index_offset;
struct snd_ctl_elem_info info;
const u32 pattern = 0xdeadbeef;
int ret;
guard(rwsem_read)(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, &control->id);
if (!kctl)
return -ENOENT;
index_offset = snd_ctl_get_ioff(kctl, &control->id);
vd = &kctl->vd[index_offset];
if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) || !kctl->get)
return -EPERM;
snd_ctl_build_ioff(&control->id, kctl, index_offset);
#ifdef CONFIG_SND_CTL_DEBUG
/* info is needed only for validation */
memset(&info, 0, sizeof(info));
info.id = control->id;
ret = __snd_ctl_elem_info(card, kctl, &info, NULL);
if (ret < 0)
return ret;
#endif
if (!snd_ctl_skip_validation(&info))
fill_remaining_elem_value(control, &info, pattern);
ret = kctl->get(kctl, control);
if (ret < 0)
return ret;
if (!snd_ctl_skip_validation(&info) &&
sanity_check_elem_value(card, control, &info, pattern) < 0) {
dev_err(card->dev,
"control %i:%i:%i:%s:%i: access overflow\n",
control->id.iface, control->id.device,
control->id.subdevice, control->id.name,
control->id.index);
return -EINVAL;
}
return 0;
}
static int snd_ctl_elem_read_user(struct snd_card *card,
struct snd_ctl_elem_value __user *_control)
{
struct snd_ctl_elem_value *control __free(kfree) = NULL;
int result;
control = memdup_user(_control, sizeof(*control));
if (IS_ERR(control))
return PTR_ERR(control);
result = snd_power_ref_and_wait(card);
if (result)
return result;
result = snd_ctl_elem_read(card, control);
snd_power_unref(card);
if (result < 0)
return result;
if (copy_to_user(_control, control, sizeof(*control)))
return -EFAULT;
return result;
}
static int snd_ctl_elem_write(struct snd_card *card, struct snd_ctl_file *file,
struct snd_ctl_elem_value *control)
{
struct snd_kcontrol *kctl;
struct snd_kcontrol_volatile *vd;
unsigned int index_offset;
int result = 0;
down_write(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, &control->id);
if (kctl == NULL) {
up_write(&card->controls_rwsem);
return -ENOENT;
}
index_offset = snd_ctl_get_ioff(kctl, &control->id);
vd = &kctl->vd[index_offset];
if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_WRITE) || kctl->put == NULL ||
(file && vd->owner && vd->owner != file)) {
up_write(&card->controls_rwsem);
return -EPERM;
}
snd_ctl_build_ioff(&control->id, kctl, index_offset);
/* validate input values */
if (IS_ENABLED(CONFIG_SND_CTL_INPUT_VALIDATION)) {
struct snd_ctl_elem_info info;
memset(&info, 0, sizeof(info));
info.id = control->id;
result = __snd_ctl_elem_info(card, kctl, &info, NULL);
if (!result)
result = sanity_check_input_values(card, control, &info,
false);
}
if (!result)
result = kctl->put(kctl, control);
if (result < 0) {
up_write(&card->controls_rwsem);
return result;
}
if (result > 0) {
downgrade_write(&card->controls_rwsem);
snd_ctl_notify_one(card, SNDRV_CTL_EVENT_MASK_VALUE, kctl, index_offset);
up_read(&card->controls_rwsem);
} else {
up_write(&card->controls_rwsem);
}
return 0;
}
static int snd_ctl_elem_write_user(struct snd_ctl_file *file,
struct snd_ctl_elem_value __user *_control)
{
struct snd_ctl_elem_value *control __free(kfree) = NULL;
struct snd_card *card;
int result;
control = memdup_user(_control, sizeof(*control));
if (IS_ERR(control))
return PTR_ERR(control);
card = file->card;
result = snd_power_ref_and_wait(card);
if (result < 0)
return result;
result = snd_ctl_elem_write(card, file, control);
snd_power_unref(card);
if (result < 0)
return result;
if (copy_to_user(_control, control, sizeof(*control)))
return -EFAULT;
return result;
}
static int snd_ctl_elem_lock(struct snd_ctl_file *file,
struct snd_ctl_elem_id __user *_id)
{
struct snd_card *card = file->card;
struct snd_ctl_elem_id id;
struct snd_kcontrol *kctl;
struct snd_kcontrol_volatile *vd;
if (copy_from_user(&id, _id, sizeof(id)))
return -EFAULT;
guard(rwsem_write)(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, &id);
if (!kctl)
return -ENOENT;
vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
if (vd->owner)
return -EBUSY;
vd->owner = file;
return 0;
}
static int snd_ctl_elem_unlock(struct snd_ctl_file *file,
struct snd_ctl_elem_id __user *_id)
{
struct snd_card *card = file->card;
struct snd_ctl_elem_id id;
struct snd_kcontrol *kctl;
struct snd_kcontrol_volatile *vd;
if (copy_from_user(&id, _id, sizeof(id)))
return -EFAULT;
guard(rwsem_write)(&card->controls_rwsem);
kctl = snd_ctl_find_id(card, &id);
if (!kctl)
return -ENOENT;
vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
if (!vd->owner)
return -EINVAL;
if (vd->owner != file)
return -EPERM;
vd->owner = NULL;
return 0;
}
struct user_element {
struct snd_ctl_elem_info info;
struct snd_card *card;
char *elem_data; /* element data */
unsigned long elem_data_size; /* size of element data in bytes */
void *tlv_data; /* TLV data */
unsigned long tlv_data_size; /* TLV data size */
void *priv_data; /* private data (like strings for enumerated type) */
};
// check whether the addition (in bytes) of user ctl element may overflow the limit.
static bool check_user_elem_overflow(struct snd_card *card, ssize_t add)
{
return (ssize_t)card->user_ctl_alloc_size + add > max_user_ctl_alloc_size;
}
static int snd_ctl_elem_user_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *uinfo)
{
struct user_element *ue = kcontrol->private_data;
unsigned int offset;
offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
*uinfo = ue->info;
snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
return 0;
}
static int snd_ctl_elem_user_enum_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *uinfo)
{
struct user_element *ue = kcontrol->private_data;
const char *names;
unsigned int item;
unsigned int offset;
item = uinfo->value.enumerated.item;
offset = snd_ctl_get_ioff(kcontrol, &uinfo->id);
*uinfo = ue->info;
snd_ctl_build_ioff(&uinfo->id, kcontrol, offset);
item = min(item, uinfo->value.enumerated.items - 1);
uinfo->value.enumerated.item = item;
names = ue->priv_data;
for (; item > 0; --item)
names += strlen(names) + 1;
strcpy(uinfo->value.enumerated.name, names);
return 0;
}
static int snd_ctl_elem_user_get(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
struct user_element *ue = kcontrol->private_data;
unsigned int size = ue->elem_data_size;
char *src = ue->elem_data +
snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
memcpy(&ucontrol->value, src, size);
return 0;
}
static int snd_ctl_elem_user_put(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_value *ucontrol)
{
int err, change;
struct user_element *ue = kcontrol->private_data;
unsigned int size = ue->elem_data_size;
char *dst = ue->elem_data +
snd_ctl_get_ioff(kcontrol, &ucontrol->id) * size;
err = sanity_check_input_values(ue->card, ucontrol, &ue->info, false);
if (err < 0)
return err;
change = memcmp(&ucontrol->value, dst, size) != 0;
if (change)
memcpy(dst, &ucontrol->value, size);
return change;
}
/* called in controls_rwsem write lock */
static int replace_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
unsigned int size)
{
struct user_element *ue = kctl->private_data;
unsigned int *container;
unsigned int mask = 0;
int i;
int change;
lockdep_assert_held_write(&ue->card->controls_rwsem);
if (size > 1024 * 128) /* sane value */
return -EINVAL;
// does the TLV size change cause overflow?
if (check_user_elem_overflow(ue->card, (ssize_t)(size - ue->tlv_data_size)))
return -ENOMEM;
container = vmemdup_user(buf, size);
if (IS_ERR(container))
return PTR_ERR(container);
change = ue->tlv_data_size != size;
if (!change)
change = memcmp(ue->tlv_data, container, size) != 0;
if (!change) {
kvfree(container);
return 0;
}
if (ue->tlv_data == NULL) {
/* Now TLV data is available. */
for (i = 0; i < kctl->count; ++i)
kctl->vd[i].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
mask = SNDRV_CTL_EVENT_MASK_INFO;
} else {
ue->card->user_ctl_alloc_size -= ue->tlv_data_size;
ue->tlv_data_size = 0;
kvfree(ue->tlv_data);
}
ue->tlv_data = container;
ue->tlv_data_size = size;
// decremented at private_free.
ue->card->user_ctl_alloc_size += size;
mask |= SNDRV_CTL_EVENT_MASK_TLV;
for (i = 0; i < kctl->count; ++i)
snd_ctl_notify_one(ue->card, mask, kctl, i);
return change;
}
static int read_user_tlv(struct snd_kcontrol *kctl, unsigned int __user *buf,
unsigned int size)
{
struct user_element *ue = kctl->private_data;
if (ue->tlv_data_size == 0 || ue->tlv_data == NULL)
return -ENXIO;
if (size < ue->tlv_data_size)
return -ENOSPC;
if (copy_to_user(buf, ue->tlv_data, ue->tlv_data_size))
return -EFAULT;
return 0;
}
static int snd_ctl_elem_user_tlv(struct snd_kcontrol *kctl, int op_flag,
unsigned int size, unsigned int __user *buf)
{
if (op_flag == SNDRV_CTL_TLV_OP_WRITE)
return replace_user_tlv(kctl, buf, size);
else
return read_user_tlv(kctl, buf, size);
}
/* called in controls_rwsem write lock */
static int snd_ctl_elem_init_enum_names(struct user_element *ue)
{
char *names, *p;
size_t buf_len, name_len;
unsigned int i;
const uintptr_t user_ptrval = ue->info.value.enumerated.names_ptr;
lockdep_assert_held_write(&ue->card->controls_rwsem);
buf_len = ue->info.value.enumerated.names_length;
if (buf_len > 64 * 1024)
return -EINVAL;
if (check_user_elem_overflow(ue->card, buf_len))
return -ENOMEM;
names = vmemdup_user((const void __user *)user_ptrval, buf_len);
if (IS_ERR(names))
return PTR_ERR(names);
/* check that there are enough valid names */
p = names;
for (i = 0; i < ue->info.value.enumerated.items; ++i) {
name_len = strnlen(p, buf_len);
if (name_len == 0 || name_len >= 64 || name_len == buf_len) {
kvfree(names);
return -EINVAL;
}
p += name_len + 1;
buf_len -= name_len + 1;
}
ue->priv_data = names;
ue->info.value.enumerated.names_ptr = 0;
// increment the allocation size; decremented again at private_free.
ue->card->user_ctl_alloc_size += ue->info.value.enumerated.names_length;
return 0;
}
static size_t compute_user_elem_size(size_t size, unsigned int count)
{
return sizeof(struct user_element) + size * count;
}
static void snd_ctl_elem_user_free(struct snd_kcontrol *kcontrol)
{
struct user_element *ue = kcontrol->private_data;
// decrement the allocation size.
ue->card->user_ctl_alloc_size -= compute_user_elem_size(ue->elem_data_size, kcontrol->count);
ue->card->user_ctl_alloc_size -= ue->tlv_data_size;
if (ue->priv_data)
ue->card->user_ctl_alloc_size -= ue->info.value.enumerated.names_length;
kvfree(ue->tlv_data);
kvfree(ue->priv_data);
kfree(ue);
}
static int snd_ctl_elem_add(struct snd_ctl_file *file,
struct snd_ctl_elem_info *info, int replace)
{
struct snd_card *card = file->card;
struct snd_kcontrol *kctl;
unsigned int count;
unsigned int access;
long private_size;
size_t alloc_size;
struct user_element *ue;
unsigned int offset;
int err;
if (!*info->id.name)
return -EINVAL;
if (strnlen(info->id.name, sizeof(info->id.name)) >= sizeof(info->id.name))
return -EINVAL;
/* Delete a control to replace them if needed. */
if (replace) {
info->id.numid = 0;
err = snd_ctl_remove_user_ctl(file, &info->id);
if (err)
return err;
}
/* Check the number of elements for this userspace control. */
count = info->owner;
if (count == 0)
count = 1;
if (count > MAX_CONTROL_COUNT)
return -EINVAL;
/* Arrange access permissions if needed. */
access = info->access;
if (access == 0)
access = SNDRV_CTL_ELEM_ACCESS_READWRITE;
access &= (SNDRV_CTL_ELEM_ACCESS_READWRITE |
SNDRV_CTL_ELEM_ACCESS_INACTIVE |
SNDRV_CTL_ELEM_ACCESS_TLV_WRITE);
/* In initial state, nothing is available as TLV container. */
if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
access |= SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
access |= SNDRV_CTL_ELEM_ACCESS_USER;
/*
* Check information and calculate the size of data specific to
* this userspace control.
*/
/* pass NULL to card for suppressing error messages */
err = snd_ctl_check_elem_info(NULL, info);
if (err < 0)
return err;
/* user-space control doesn't allow zero-size data */
if (info->count < 1)
return -EINVAL;
private_size = value_sizes[info->type] * info->count;
alloc_size = compute_user_elem_size(private_size, count);
guard(rwsem_write)(&card->controls_rwsem);
if (check_user_elem_overflow(card, alloc_size))
return -ENOMEM;
/*
* Keep memory object for this userspace control. After passing this
* code block, the instance should be freed by snd_ctl_free_one().
*
* Note that these elements in this control are locked.
*/
err = snd_ctl_new(&kctl, count, access, file);
if (err < 0)
return err;
memcpy(&kctl->id, &info->id, sizeof(kctl->id));
ue = kzalloc(alloc_size, GFP_KERNEL);
if (!ue) {
kfree(kctl);
return -ENOMEM;
}
kctl->private_data = ue;
kctl->private_free = snd_ctl_elem_user_free;
// increment the allocated size; decremented again at private_free.
card->user_ctl_alloc_size += alloc_size;
/* Set private data for this userspace control. */
ue->card = card;
ue->info = *info;
ue->info.access = 0;
ue->elem_data = (char *)ue + sizeof(*ue);
ue->elem_data_size = private_size;
if (ue->info.type == SNDRV_CTL_ELEM_TYPE_ENUMERATED) {
err = snd_ctl_elem_init_enum_names(ue);
if (err < 0) {
snd_ctl_free_one(kctl);
return err;
}
}
/* Set callback functions. */
if (info->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
kctl->info = snd_ctl_elem_user_enum_info;
else
kctl->info = snd_ctl_elem_user_info;
if (access & SNDRV_CTL_ELEM_ACCESS_READ)
kctl->get = snd_ctl_elem_user_get;
if (access & SNDRV_CTL_ELEM_ACCESS_WRITE)
kctl->put = snd_ctl_elem_user_put;
if (access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE)
kctl->tlv.c = snd_ctl_elem_user_tlv;
/* This function manage to free the instance on failure. */
err = __snd_ctl_add_replace(card, kctl, CTL_ADD_EXCLUSIVE);
if (err < 0) {
snd_ctl_free_one(kctl);
return err;
}
offset = snd_ctl_get_ioff(kctl, &info->id);
snd_ctl_build_ioff(&info->id, kctl, offset);
/*
* Here we cannot fill any field for the number of elements added by
* this operation because there're no specific fields. The usage of
* 'owner' field for this purpose may cause any bugs to userspace
* applications because the field originally means PID of a process
* which locks the element.
*/
return 0;
}
static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
struct snd_ctl_elem_info __user *_info, int replace)
{
struct snd_ctl_elem_info info;
int err;
if (copy_from_user(&info, _info, sizeof(info)))
return -EFAULT;
err = snd_ctl_elem_add(file, &info, replace);
if (err < 0)
return err;
if (copy_to_user(_info, &info, sizeof(info))) {
snd_ctl_remove_user_ctl(file, &info.id);
return -EFAULT;
}
return 0;
}
static int snd_ctl_elem_remove(struct snd_ctl_file *file,
struct snd_ctl_elem_id __user *_id)
{
struct snd_ctl_elem_id id;
if (copy_from_user(&id, _id, sizeof(id)))
return -EFAULT;
return snd_ctl_remove_user_ctl(file, &id);
}
static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
{
int subscribe;
if (get_user(subscribe, ptr))
return -EFAULT;
if (subscribe < 0) {
subscribe = file->subscribed;
if (put_user(subscribe, ptr))
return -EFAULT;
return 0;
}
if (subscribe) {
file->subscribed = 1;
return 0;
} else if (file->subscribed) {
snd_ctl_empty_read_queue(file);
file->subscribed = 0;
}
return 0;
}
static int call_tlv_handler(struct snd_ctl_file *file, int op_flag,
struct snd_kcontrol *kctl,
struct snd_ctl_elem_id *id,
unsigned int __user *buf, unsigned int size)
{
static const struct {
int op;
int perm;
} pairs[] = {
{SNDRV_CTL_TLV_OP_READ, SNDRV_CTL_ELEM_ACCESS_TLV_READ},
{SNDRV_CTL_TLV_OP_WRITE, SNDRV_CTL_ELEM_ACCESS_TLV_WRITE},
{SNDRV_CTL_TLV_OP_CMD, SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND},
};
struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
int i;
/* Check support of the request for this element. */
for (i = 0; i < ARRAY_SIZE(pairs); ++i) {
if (op_flag == pairs[i].op && (vd->access & pairs[i].perm))
break;
}
if (i == ARRAY_SIZE(pairs))
return -ENXIO;
if (kctl->tlv.c == NULL)
return -ENXIO;
/* Write and command operations are not allowed for locked element. */
if (op_flag != SNDRV_CTL_TLV_OP_READ &&
vd->owner != NULL && vd->owner != file)
return -EPERM;
return kctl->tlv.c(kctl, op_flag, size, buf);
}
static int read_tlv_buf(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id,
unsigned int __user *buf, unsigned int size)
{
struct snd_kcontrol_volatile *vd = &kctl->vd[snd_ctl_get_ioff(kctl, id)];
unsigned int len;
if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ))
return -ENXIO;
if (kctl->tlv.p == NULL)
return -ENXIO;
len = sizeof(unsigned int) * 2 + kctl->tlv.p[1];
if (size < len)
return -ENOMEM;
if (copy_to_user(buf, kctl->tlv.p, len))
return -EFAULT;
return 0;
}
static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
struct snd_ctl_tlv __user *buf,
int op_flag)
{
struct snd_ctl_tlv header;
unsigned int __user *container;
unsigned int container_size;
struct snd_kcontrol *kctl;
struct snd_ctl_elem_id id;
struct snd_kcontrol_volatile *vd;
lockdep_assert_held(&file->card->controls_rwsem);
if (copy_from_user(&header, buf, sizeof(header)))
return -EFAULT;
/* In design of control core, numerical ID starts at 1. */
if (header.numid == 0)
return -EINVAL;
/* At least, container should include type and length fields. */
if (header.length < sizeof(unsigned int) * 2)
return -EINVAL;
container_size = header.length;
container = buf->tlv;
kctl = snd_ctl_find_numid(file->card, header.numid);
if (kctl == NULL)
return -ENOENT;
/* Calculate index of the element in this set. */
id = kctl->id;
snd_ctl_build_ioff(&id, kctl, header.numid - id.numid);
vd = &kctl->vd[snd_ctl_get_ioff(kctl, &id)];
if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
return call_tlv_handler(file, op_flag, kctl, &id, container,
container_size);
} else {
if (op_flag == SNDRV_CTL_TLV_OP_READ) {
return read_tlv_buf(kctl, &id, container,
container_size);
}
}
/* Not supported. */
return -ENXIO;
}
static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct snd_ctl_file *ctl;
struct snd_card *card;
struct snd_kctl_ioctl *p;
void __user *argp = (void __user *)arg;
int __user *ip = argp;
int err;
ctl = file->private_data;
card = ctl->card;
if (snd_BUG_ON(!card))
return -ENXIO;
switch (cmd) {
case SNDRV_CTL_IOCTL_PVERSION:
return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
case SNDRV_CTL_IOCTL_CARD_INFO:
return snd_ctl_card_info(card, ctl, cmd, argp);
case SNDRV_CTL_IOCTL_ELEM_LIST:
return snd_ctl_elem_list_user(card, argp);
case SNDRV_CTL_IOCTL_ELEM_INFO:
return snd_ctl_elem_info_user(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_READ:
return snd_ctl_elem_read_user(card, argp);
case SNDRV_CTL_IOCTL_ELEM_WRITE:
return snd_ctl_elem_write_user(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_LOCK:
return snd_ctl_elem_lock(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
return snd_ctl_elem_unlock(ctl, argp);
case SNDRV_CTL_IOCTL_ELEM_ADD:
return snd_ctl_elem_add_user(ctl, argp, 0);
case SNDRV_CTL_IOCTL_ELEM_REPLACE:
return snd_ctl_elem_add_user(ctl, argp, 1);
case SNDRV_CTL_IOCTL_ELEM_REMOVE:
return snd_ctl_elem_remove(ctl, argp);
case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
return snd_ctl_subscribe_events(ctl, ip);
case SNDRV_CTL_IOCTL_TLV_READ:
err = snd_power_ref_and_wait(card);
if (err < 0)
return err;
scoped_guard(rwsem_read, &card->controls_rwsem)
err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
snd_power_unref(card);
return err;
case SNDRV_CTL_IOCTL_TLV_WRITE:
err = snd_power_ref_and_wait(card);
if (err < 0)
return err;
scoped_guard(rwsem_write, &card->controls_rwsem)
err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
snd_power_unref(card);
return err;
case SNDRV_CTL_IOCTL_TLV_COMMAND:
err = snd_power_ref_and_wait(card);
if (err < 0)
return err;
scoped_guard(rwsem_write, &card->controls_rwsem)
err = snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
snd_power_unref(card);
return err;
case SNDRV_CTL_IOCTL_POWER:
return -ENOPROTOOPT;
case SNDRV_CTL_IOCTL_POWER_STATE:
return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
}
guard(rwsem_read)(&snd_ioctl_rwsem);
list_for_each_entry(p, &snd_control_ioctls, list) {
err = p->fioctl(card, ctl, cmd, arg);
if (err != -ENOIOCTLCMD)
return err;
}
dev_dbg(card->dev, "unknown ioctl = 0x%x\n", cmd);
return -ENOTTY;
}
static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
size_t count, loff_t * offset)
{
struct snd_ctl_file *ctl;
int err = 0;
ssize_t result = 0;
ctl = file->private_data;
if (snd_BUG_ON(!ctl || !ctl->card))
return -ENXIO;
if (!ctl->subscribed)
return -EBADFD;
if (count < sizeof(struct snd_ctl_event))
return -EINVAL;
spin_lock_irq(&ctl->read_lock);
while (count >= sizeof(struct snd_ctl_event)) {
struct snd_ctl_event ev;
struct snd_kctl_event *kev;
while (list_empty(&ctl->events)) {
wait_queue_entry_t wait;
if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
err = -EAGAIN;
goto __end_lock;
}
init_waitqueue_entry(&wait, current);
add_wait_queue(&ctl->change_sleep, &wait);
set_current_state(TASK_INTERRUPTIBLE);
spin_unlock_irq(&ctl->read_lock);
schedule();
remove_wait_queue(&ctl->change_sleep, &wait);
if (ctl->card->shutdown)
return -ENODEV;
if (signal_pending(current))
return -ERESTARTSYS;
spin_lock_irq(&ctl->read_lock);
}
kev = snd_kctl_event(ctl->events.next);
ev.type = SNDRV_CTL_EVENT_ELEM;
ev.data.elem.mask = kev->mask;
ev.data.elem.id = kev->id;
list_del(&kev->list);
spin_unlock_irq(&ctl->read_lock);
kfree(kev);
if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
err = -EFAULT;
goto __end;
}
spin_lock_irq(&ctl->read_lock);
buffer += sizeof(struct snd_ctl_event);
count -= sizeof(struct snd_ctl_event);
result += sizeof(struct snd_ctl_event);
}
__end_lock:
spin_unlock_irq(&ctl->read_lock);
__end:
return result > 0 ? result : err;
}
static __poll_t snd_ctl_poll(struct file *file, poll_table * wait)
{
__poll_t mask;
struct snd_ctl_file *ctl;
ctl = file->private_data;
if (!ctl->subscribed)
return 0;
poll_wait(file, &ctl->change_sleep, wait);
mask = 0;
if (!list_empty(&ctl->events))
mask |= EPOLLIN | EPOLLRDNORM;
return mask;
}
/*
* register the device-specific control-ioctls.
* called from each device manager like pcm.c, hwdep.c, etc.
*/
static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
{
struct snd_kctl_ioctl *pn;
pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
if (pn == NULL)
return -ENOMEM;
pn->fioctl = fcn;
guard(rwsem_write)(&snd_ioctl_rwsem);
list_add_tail(&pn->list, lists);
return 0;
}
/**
* snd_ctl_register_ioctl - register the device-specific control-ioctls
* @fcn: ioctl callback function
*
* called from each device manager like pcm.c, hwdep.c, etc.
*
* Return: zero if successful, or a negative error code
*/
int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
{
return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
}
EXPORT_SYMBOL(snd_ctl_register_ioctl);
#ifdef CONFIG_COMPAT
/**
* snd_ctl_register_ioctl_compat - register the device-specific 32bit compat
* control-ioctls
* @fcn: ioctl callback function
*
* Return: zero if successful, or a negative error code
*/
int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
{
return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
}
EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
#endif
/*
* de-register the device-specific control-ioctls.
*/
static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
struct list_head *lists)
{
struct snd_kctl_ioctl *p;
if (snd_BUG_ON(!fcn))
return -EINVAL;
guard(rwsem_write)(&snd_ioctl_rwsem);
list_for_each_entry(p, lists, list) {
if (p->fioctl == fcn) {
list_del(&p->list);
kfree(p);
return 0;
}
}
snd_BUG();
return -EINVAL;
}
/**
* snd_ctl_unregister_ioctl - de-register the device-specific control-ioctls
* @fcn: ioctl callback function to unregister
*
* Return: zero if successful, or a negative error code
*/
int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
{
return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
}
EXPORT_SYMBOL(snd_ctl_unregister_ioctl);
#ifdef CONFIG_COMPAT
/**
* snd_ctl_unregister_ioctl_compat - de-register the device-specific compat
* 32bit control-ioctls
* @fcn: ioctl callback function to unregister
*
* Return: zero if successful, or a negative error code
*/
int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
{
return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
}
EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
#endif
static int snd_ctl_fasync(int fd, struct file * file, int on)
{
struct snd_ctl_file *ctl;
ctl = file->private_data;
return snd_fasync_helper(fd, file, on, &ctl->fasync);
}
/* return the preferred subdevice number if already assigned;
* otherwise return -1
*/
int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type)
{
struct snd_ctl_file *kctl;
int subdevice = -1;
guard(read_lock_irqsave)(&card->controls_rwlock);
list_for_each_entry(kctl, &card->ctl_files, list) {
if (kctl->pid == task_pid(current)) {
subdevice = kctl->preferred_subdevice[type];
if (subdevice != -1)
break;
}
}
return subdevice;
}
EXPORT_SYMBOL_GPL(snd_ctl_get_preferred_subdevice);
/*
* ioctl32 compat
*/
#ifdef CONFIG_COMPAT
#include "control_compat.c"
#else
#define snd_ctl_ioctl_compat NULL
#endif
/*
* control layers (audio LED etc.)
*/
/**
* snd_ctl_request_layer - request to use the layer
* @module_name: Name of the kernel module (NULL == build-in)
*
* Return: zero if successful, or an error code when the module cannot be loaded
*/
int snd_ctl_request_layer(const char *module_name)
{
struct snd_ctl_layer_ops *lops;
if (module_name == NULL)
return 0;
scoped_guard(rwsem_read, &snd_ctl_layer_rwsem) {
for (lops = snd_ctl_layer; lops; lops = lops->next)
if (strcmp(lops->module_name, module_name) == 0)
return 0;
}
return request_module(module_name);
}
EXPORT_SYMBOL_GPL(snd_ctl_request_layer);
/**
* snd_ctl_register_layer - register new control layer
* @lops: operation structure
*
* The new layer can track all control elements and do additional
* operations on top (like audio LED handling).
*/
void snd_ctl_register_layer(struct snd_ctl_layer_ops *lops)
{
struct snd_card *card;
int card_number;
scoped_guard(rwsem_write, &snd_ctl_layer_rwsem) {
lops->next = snd_ctl_layer;
snd_ctl_layer = lops;
}
for (card_number = 0; card_number < SNDRV_CARDS; card_number++) {
card = snd_card_ref(card_number);
if (card) {
scoped_guard(rwsem_read, &card->controls_rwsem)
lops->lregister(card);
snd_card_unref(card);
}
}
}
EXPORT_SYMBOL_GPL(snd_ctl_register_layer);
/**
* snd_ctl_disconnect_layer - disconnect control layer
* @lops: operation structure
*
* It is expected that the information about tracked cards
* is freed before this call (the disconnect callback is
* not called here).
*/
void snd_ctl_disconnect_layer(struct snd_ctl_layer_ops *lops)
{
struct snd_ctl_layer_ops *lops2, *prev_lops2;
guard(rwsem_write)(&snd_ctl_layer_rwsem);
for (lops2 = snd_ctl_layer, prev_lops2 = NULL; lops2; lops2 = lops2->next) {
if (lops2 == lops) {
if (!prev_lops2)
snd_ctl_layer = lops->next;
else
prev_lops2->next = lops->next;
break;
}
prev_lops2 = lops2;
}
}
EXPORT_SYMBOL_GPL(snd_ctl_disconnect_layer);
/*
* INIT PART
*/
static const struct file_operations snd_ctl_f_ops =
{
.owner = THIS_MODULE,
.read = snd_ctl_read,
.open = snd_ctl_open,
.release = snd_ctl_release,
.poll = snd_ctl_poll,
.unlocked_ioctl = snd_ctl_ioctl,
.compat_ioctl = snd_ctl_ioctl_compat,
.fasync = snd_ctl_fasync,
};
/* call lops under rwsems; called from snd_ctl_dev_*() below() */
#define call_snd_ctl_lops(_card, _op) \
do { \
struct snd_ctl_layer_ops *lops; \
guard(rwsem_read)(&(_card)->controls_rwsem); \
guard(rwsem_read)(&snd_ctl_layer_rwsem); \
for (lops = snd_ctl_layer; lops; lops = lops->next) \
lops->_op(_card); \
} while (0)
/*
* registration of the control device
*/
static int snd_ctl_dev_register(struct snd_device *device)
{
struct snd_card *card = device->device_data;
int err;
err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
&snd_ctl_f_ops, card, card->ctl_dev);
if (err < 0)
return err;
call_snd_ctl_lops(card, lregister);
return 0;
}
/*
* disconnection of the control device
*/
static int snd_ctl_dev_disconnect(struct snd_device *device)
{
struct snd_card *card = device->device_data;
struct snd_ctl_file *ctl;
scoped_guard(read_lock_irqsave, &card->controls_rwlock) {
list_for_each_entry(ctl, &card->ctl_files, list) {
wake_up(&ctl->change_sleep);
snd_kill_fasync(ctl->fasync, SIGIO, POLL_ERR);
}
}
call_snd_ctl_lops(card, ldisconnect);
return snd_unregister_device(card->ctl_dev);
}
/*
* free all controls
*/
static int snd_ctl_dev_free(struct snd_device *device)
{
struct snd_card *card = device->device_data;
struct snd_kcontrol *control;
scoped_guard(rwsem_write, &card->controls_rwsem) {
while (!list_empty(&card->controls)) {
control = snd_kcontrol(card->controls.next);
__snd_ctl_remove(card, control, false);
}
#ifdef CONFIG_SND_CTL_FAST_LOOKUP
xa_destroy(&card->ctl_numids);
xa_destroy(&card->ctl_hash);
#endif
}
put_device(card->ctl_dev);
return 0;
}
/*
* create control core:
* called from init.c
*/
int snd_ctl_create(struct snd_card *card)
{
static const struct snd_device_ops ops = {
.dev_free = snd_ctl_dev_free,
.dev_register = snd_ctl_dev_register,
.dev_disconnect = snd_ctl_dev_disconnect,
};
int err;
if (snd_BUG_ON(!card))
return -ENXIO;
if (snd_BUG_ON(card->number < 0 || card->number >= SNDRV_CARDS))
return -ENXIO;
err = snd_device_alloc(&card->ctl_dev, card);
if (err < 0)
return err;
dev_set_name(card->ctl_dev, "controlC%d", card->number);
err = snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
if (err < 0)
put_device(card->ctl_dev);
return err;
}
/*
* Frequently used control callbacks/helpers
*/
/**
* snd_ctl_boolean_mono_info - Helper function for a standard boolean info
* callback with a mono channel
* @kcontrol: the kcontrol instance
* @uinfo: info to store
*
* This is a function that can be used as info callback for a standard
* boolean control with a single mono channel.
*
* Return: Zero (always successful)
*/
int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *uinfo)
{
uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
uinfo->count = 1;
uinfo->value.integer.min = 0;
uinfo->value.integer.max = 1;
return 0;
}
EXPORT_SYMBOL(snd_ctl_boolean_mono_info);
/**
* snd_ctl_boolean_stereo_info - Helper function for a standard boolean info
* callback with stereo two channels
* @kcontrol: the kcontrol instance
* @uinfo: info to store
*
* This is a function that can be used as info callback for a standard
* boolean control with stereo two channels.
*
* Return: Zero (always successful)
*/
int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
struct snd_ctl_elem_info *uinfo)
{
uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
uinfo->count = 2;
uinfo->value.integer.min = 0;
uinfo->value.integer.max = 1;
return 0;
}
EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);
/**
* snd_ctl_enum_info - fills the info structure for an enumerated control
* @info: the structure to be filled
* @channels: the number of the control's channels; often one
* @items: the number of control values; also the size of @names
* @names: an array containing the names of all control values
*
* Sets all required fields in @info to their appropriate values.
* If the control's accessibility is not the default (readable and writable),
* the caller has to fill @info->access.
*
* Return: Zero (always successful)
*/
int snd_ctl_enum_info(struct snd_ctl_elem_info *info, unsigned int channels,
unsigned int items, const char *const names[])
{
info->type = SNDRV_CTL_ELEM_TYPE_ENUMERATED;
info->count = channels;
info->value.enumerated.items = items;
if (!items)
return 0;
if (info->value.enumerated.item >= items)
info->value.enumerated.item = items - 1;
WARN(strlen(names[info->value.enumerated.item]) >= sizeof(info->value.enumerated.name),
"ALSA: too long item name '%s'\n",
names[info->value.enumerated.item]);
strscpy(info->value.enumerated.name,
names[info->value.enumerated.item],
sizeof(info->value.enumerated.name));
return 0;
}
EXPORT_SYMBOL(snd_ctl_enum_info);
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