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TOMOYO Linux Cross Reference
Linux/sound/core/control.c

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

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