1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Initialization routines
4  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5  */
6 
7 #include <linux/init.h>
8 #include <linux/sched.h>
9 #include <linux/module.h>
10 #include <linux/device.h>
11 #include <linux/file.h>
12 #include <linux/slab.h>
13 #include <linux/time.h>
14 #include <linux/ctype.h>
15 #include <linux/pm.h>
16 #include <linux/debugfs.h>
17 #include <linux/completion.h>
18 #include <linux/interrupt.h>
19 
20 #include <sound/core.h>
21 #include <sound/control.h>
22 #include <sound/info.h>
23 
24 /* monitor files for graceful shutdown (hotplug) */
25 struct snd_monitor_file {
26 	struct file *file;
27 	const struct file_operations *disconnected_f_op;
28 	struct list_head shutdown_list;	/* still need to shutdown */
29 	struct list_head list;	/* link of monitor files */
30 };
31 
32 static DEFINE_SPINLOCK(shutdown_lock);
33 static LIST_HEAD(shutdown_files);
34 
35 static const struct file_operations snd_shutdown_f_ops;
36 
37 /* locked for registering/using */
38 static DECLARE_BITMAP(snd_cards_lock, SNDRV_CARDS);
39 static struct snd_card *snd_cards[SNDRV_CARDS];
40 
41 static DEFINE_MUTEX(snd_card_mutex);
42 
43 static char *slots[SNDRV_CARDS];
44 module_param_array(slots, charp, NULL, 0444);
45 MODULE_PARM_DESC(slots, "Module names assigned to the slots.");
46 
47 /* return non-zero if the given index is reserved for the given
48  * module via slots option
49  */
module_slot_match(struct module * module,int idx)50 static int module_slot_match(struct module *module, int idx)
51 {
52 	int match = 1;
53 #ifdef MODULE
54 	const char *s1, *s2;
55 
56 	if (!module || !*module->name || !slots[idx])
57 		return 0;
58 
59 	s1 = module->name;
60 	s2 = slots[idx];
61 	if (*s2 == '!') {
62 		match = 0; /* negative match */
63 		s2++;
64 	}
65 	/* compare module name strings
66 	 * hyphens are handled as equivalent with underscore
67 	 */
68 	for (;;) {
69 		char c1 = *s1++;
70 		char c2 = *s2++;
71 		if (c1 == '-')
72 			c1 = '_';
73 		if (c2 == '-')
74 			c2 = '_';
75 		if (c1 != c2)
76 			return !match;
77 		if (!c1)
78 			break;
79 	}
80 #endif /* MODULE */
81 	return match;
82 }
83 
84 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
85 int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
86 EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
87 #endif
88 
check_empty_slot(struct module * module,int slot)89 static int check_empty_slot(struct module *module, int slot)
90 {
91 	return !slots[slot] || !*slots[slot];
92 }
93 
94 /* return an empty slot number (>= 0) found in the given bitmask @mask.
95  * @mask == -1 == 0xffffffff means: take any free slot up to 32
96  * when no slot is available, return the original @mask as is.
97  */
get_slot_from_bitmask(int mask,int (* check)(struct module *,int),struct module * module)98 static int get_slot_from_bitmask(int mask, int (*check)(struct module *, int),
99 				 struct module *module)
100 {
101 	int slot;
102 
103 	for (slot = 0; slot < SNDRV_CARDS; slot++) {
104 		if (slot < 32 && !(mask & (1U << slot)))
105 			continue;
106 		if (!test_bit(slot, snd_cards_lock)) {
107 			if (check(module, slot))
108 				return slot; /* found */
109 		}
110 	}
111 	return mask; /* unchanged */
112 }
113 
114 /* the default release callback set in snd_device_alloc() */
default_release_alloc(struct device * dev)115 static void default_release_alloc(struct device *dev)
116 {
117 	kfree(dev);
118 }
119 
120 /**
121  * snd_device_alloc - Allocate and initialize struct device for sound devices
122  * @dev_p: pointer to store the allocated device
123  * @card: card to assign, optional
124  *
125  * For releasing the allocated device, call put_device().
126  */
snd_device_alloc(struct device ** dev_p,struct snd_card * card)127 int snd_device_alloc(struct device **dev_p, struct snd_card *card)
128 {
129 	struct device *dev;
130 
131 	*dev_p = NULL;
132 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
133 	if (!dev)
134 		return -ENOMEM;
135 	device_initialize(dev);
136 	if (card)
137 		dev->parent = &card->card_dev;
138 	dev->class = &sound_class;
139 	dev->release = default_release_alloc;
140 	*dev_p = dev;
141 	return 0;
142 }
143 EXPORT_SYMBOL_GPL(snd_device_alloc);
144 
145 static int snd_card_init(struct snd_card *card, struct device *parent,
146 			 int idx, const char *xid, struct module *module,
147 			 size_t extra_size);
148 static int snd_card_do_free(struct snd_card *card);
149 static const struct attribute_group card_dev_attr_group;
150 
release_card_device(struct device * dev)151 static void release_card_device(struct device *dev)
152 {
153 	snd_card_do_free(dev_to_snd_card(dev));
154 }
155 
156 /**
157  *  snd_card_new - create and initialize a soundcard structure
158  *  @parent: the parent device object
159  *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
160  *  @xid: card identification (ASCII string)
161  *  @module: top level module for locking
162  *  @extra_size: allocate this extra size after the main soundcard structure
163  *  @card_ret: the pointer to store the created card instance
164  *
165  *  The function allocates snd_card instance via kzalloc with the given
166  *  space for the driver to use freely.  The allocated struct is stored
167  *  in the given card_ret pointer.
168  *
169  *  Return: Zero if successful or a negative error code.
170  */
snd_card_new(struct device * parent,int idx,const char * xid,struct module * module,int extra_size,struct snd_card ** card_ret)171 int snd_card_new(struct device *parent, int idx, const char *xid,
172 		    struct module *module, int extra_size,
173 		    struct snd_card **card_ret)
174 {
175 	struct snd_card *card;
176 	int err;
177 
178 	if (snd_BUG_ON(!card_ret))
179 		return -EINVAL;
180 	*card_ret = NULL;
181 
182 	if (extra_size < 0)
183 		extra_size = 0;
184 	card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
185 	if (!card)
186 		return -ENOMEM;
187 
188 	err = snd_card_init(card, parent, idx, xid, module, extra_size);
189 	if (err < 0)
190 		return err; /* card is freed by error handler */
191 
192 	*card_ret = card;
193 	return 0;
194 }
195 EXPORT_SYMBOL(snd_card_new);
196 
__snd_card_release(struct device * dev,void * data)197 static void __snd_card_release(struct device *dev, void *data)
198 {
199 	snd_card_free(data);
200 }
201 
202 /**
203  * snd_devm_card_new - managed snd_card object creation
204  * @parent: the parent device object
205  * @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
206  * @xid: card identification (ASCII string)
207  * @module: top level module for locking
208  * @extra_size: allocate this extra size after the main soundcard structure
209  * @card_ret: the pointer to store the created card instance
210  *
211  * This function works like snd_card_new() but manages the allocated resource
212  * via devres, i.e. you don't need to free explicitly.
213  *
214  * When a snd_card object is created with this function and registered via
215  * snd_card_register(), the very first devres action to call snd_card_free()
216  * is added automatically.  In that way, the resource disconnection is assured
217  * at first, then released in the expected order.
218  *
219  * If an error happens at the probe before snd_card_register() is called and
220  * there have been other devres resources, you'd need to free the card manually
221  * via snd_card_free() call in the error; otherwise it may lead to UAF due to
222  * devres call orders.  You can use snd_card_free_on_error() helper for
223  * handling it more easily.
224  *
225  * Return: zero if successful, or a negative error code
226  */
snd_devm_card_new(struct device * parent,int idx,const char * xid,struct module * module,size_t extra_size,struct snd_card ** card_ret)227 int snd_devm_card_new(struct device *parent, int idx, const char *xid,
228 		      struct module *module, size_t extra_size,
229 		      struct snd_card **card_ret)
230 {
231 	struct snd_card *card;
232 	int err;
233 
234 	*card_ret = NULL;
235 	card = devres_alloc(__snd_card_release, sizeof(*card) + extra_size,
236 			    GFP_KERNEL);
237 	if (!card)
238 		return -ENOMEM;
239 	card->managed = true;
240 	err = snd_card_init(card, parent, idx, xid, module, extra_size);
241 	if (err < 0) {
242 		devres_free(card); /* in managed mode, we need to free manually */
243 		return err;
244 	}
245 
246 	devres_add(parent, card);
247 	*card_ret = card;
248 	return 0;
249 }
250 EXPORT_SYMBOL_GPL(snd_devm_card_new);
251 
252 /**
253  * snd_card_free_on_error - a small helper for handling devm probe errors
254  * @dev: the managed device object
255  * @ret: the return code from the probe callback
256  *
257  * This function handles the explicit snd_card_free() call at the error from
258  * the probe callback.  It's just a small helper for simplifying the error
259  * handling with the managed devices.
260  *
261  * Return: zero if successful, or a negative error code
262  */
snd_card_free_on_error(struct device * dev,int ret)263 int snd_card_free_on_error(struct device *dev, int ret)
264 {
265 	struct snd_card *card;
266 
267 	if (!ret)
268 		return 0;
269 	card = devres_find(dev, __snd_card_release, NULL, NULL);
270 	if (card)
271 		snd_card_free(card);
272 	return ret;
273 }
274 EXPORT_SYMBOL_GPL(snd_card_free_on_error);
275 
snd_card_init(struct snd_card * card,struct device * parent,int idx,const char * xid,struct module * module,size_t extra_size)276 static int snd_card_init(struct snd_card *card, struct device *parent,
277 			 int idx, const char *xid, struct module *module,
278 			 size_t extra_size)
279 {
280 	int err;
281 
282 	if (extra_size > 0)
283 		card->private_data = (char *)card + sizeof(struct snd_card);
284 	if (xid)
285 		strscpy(card->id, xid, sizeof(card->id));
286 	err = 0;
287 	mutex_lock(&snd_card_mutex);
288 	if (idx < 0) /* first check the matching module-name slot */
289 		idx = get_slot_from_bitmask(idx, module_slot_match, module);
290 	if (idx < 0) /* if not matched, assign an empty slot */
291 		idx = get_slot_from_bitmask(idx, check_empty_slot, module);
292 	if (idx < 0)
293 		err = -ENODEV;
294 	else if (idx < snd_ecards_limit) {
295 		if (test_bit(idx, snd_cards_lock))
296 			err = -EBUSY;	/* invalid */
297 	} else if (idx >= SNDRV_CARDS)
298 		err = -ENODEV;
299 	if (err < 0) {
300 		mutex_unlock(&snd_card_mutex);
301 		dev_err(parent, "cannot find the slot for index %d (range 0-%i), error: %d\n",
302 			 idx, snd_ecards_limit - 1, err);
303 		if (!card->managed)
304 			kfree(card); /* manually free here, as no destructor called */
305 		return err;
306 	}
307 	set_bit(idx, snd_cards_lock);		/* lock it */
308 	if (idx >= snd_ecards_limit)
309 		snd_ecards_limit = idx + 1; /* increase the limit */
310 	mutex_unlock(&snd_card_mutex);
311 	card->dev = parent;
312 	card->number = idx;
313 #ifdef MODULE
314 	WARN_ON(!module);
315 	card->module = module;
316 #endif
317 	INIT_LIST_HEAD(&card->devices);
318 	init_rwsem(&card->controls_rwsem);
319 	rwlock_init(&card->ctl_files_rwlock);
320 	INIT_LIST_HEAD(&card->controls);
321 	INIT_LIST_HEAD(&card->ctl_files);
322 #ifdef CONFIG_SND_CTL_FAST_LOOKUP
323 	xa_init(&card->ctl_numids);
324 	xa_init(&card->ctl_hash);
325 #endif
326 	spin_lock_init(&card->files_lock);
327 	INIT_LIST_HEAD(&card->files_list);
328 	mutex_init(&card->memory_mutex);
329 #ifdef CONFIG_PM
330 	init_waitqueue_head(&card->power_sleep);
331 	init_waitqueue_head(&card->power_ref_sleep);
332 	atomic_set(&card->power_ref, 0);
333 #endif
334 	init_waitqueue_head(&card->remove_sleep);
335 	card->sync_irq = -1;
336 
337 	device_initialize(&card->card_dev);
338 	card->card_dev.parent = parent;
339 	card->card_dev.class = &sound_class;
340 	card->card_dev.release = release_card_device;
341 	card->card_dev.groups = card->dev_groups;
342 	card->dev_groups[0] = &card_dev_attr_group;
343 	err = kobject_set_name(&card->card_dev.kobj, "card%d", idx);
344 	if (err < 0)
345 		goto __error;
346 
347 	snprintf(card->irq_descr, sizeof(card->irq_descr), "%s:%s",
348 		 dev_driver_string(card->dev), dev_name(&card->card_dev));
349 
350 	/* the control interface cannot be accessed from the user space until */
351 	/* snd_cards_bitmask and snd_cards are set with snd_card_register */
352 	err = snd_ctl_create(card);
353 	if (err < 0) {
354 		dev_err(parent, "unable to register control minors\n");
355 		goto __error;
356 	}
357 	err = snd_info_card_create(card);
358 	if (err < 0) {
359 		dev_err(parent, "unable to create card info\n");
360 		goto __error_ctl;
361 	}
362 
363 #ifdef CONFIG_SND_DEBUG
364 	card->debugfs_root = debugfs_create_dir(dev_name(&card->card_dev),
365 						sound_debugfs_root);
366 #endif
367 	return 0;
368 
369       __error_ctl:
370 	snd_device_free_all(card);
371       __error:
372 	put_device(&card->card_dev);
373   	return err;
374 }
375 
376 /**
377  * snd_card_ref - Get the card object from the index
378  * @idx: the card index
379  *
380  * Returns a card object corresponding to the given index or NULL if not found.
381  * Release the object via snd_card_unref().
382  *
383  * Return: a card object or NULL
384  */
snd_card_ref(int idx)385 struct snd_card *snd_card_ref(int idx)
386 {
387 	struct snd_card *card;
388 
389 	mutex_lock(&snd_card_mutex);
390 	card = snd_cards[idx];
391 	if (card)
392 		get_device(&card->card_dev);
393 	mutex_unlock(&snd_card_mutex);
394 	return card;
395 }
396 EXPORT_SYMBOL_GPL(snd_card_ref);
397 
398 /* return non-zero if a card is already locked */
snd_card_locked(int card)399 int snd_card_locked(int card)
400 {
401 	int locked;
402 
403 	mutex_lock(&snd_card_mutex);
404 	locked = test_bit(card, snd_cards_lock);
405 	mutex_unlock(&snd_card_mutex);
406 	return locked;
407 }
408 
snd_disconnect_llseek(struct file * file,loff_t offset,int orig)409 static loff_t snd_disconnect_llseek(struct file *file, loff_t offset, int orig)
410 {
411 	return -ENODEV;
412 }
413 
snd_disconnect_read(struct file * file,char __user * buf,size_t count,loff_t * offset)414 static ssize_t snd_disconnect_read(struct file *file, char __user *buf,
415 				   size_t count, loff_t *offset)
416 {
417 	return -ENODEV;
418 }
419 
snd_disconnect_write(struct file * file,const char __user * buf,size_t count,loff_t * offset)420 static ssize_t snd_disconnect_write(struct file *file, const char __user *buf,
421 				    size_t count, loff_t *offset)
422 {
423 	return -ENODEV;
424 }
425 
snd_disconnect_release(struct inode * inode,struct file * file)426 static int snd_disconnect_release(struct inode *inode, struct file *file)
427 {
428 	struct snd_monitor_file *df = NULL, *_df;
429 
430 	spin_lock(&shutdown_lock);
431 	list_for_each_entry(_df, &shutdown_files, shutdown_list) {
432 		if (_df->file == file) {
433 			df = _df;
434 			list_del_init(&df->shutdown_list);
435 			break;
436 		}
437 	}
438 	spin_unlock(&shutdown_lock);
439 
440 	if (likely(df)) {
441 		if ((file->f_flags & FASYNC) && df->disconnected_f_op->fasync)
442 			df->disconnected_f_op->fasync(-1, file, 0);
443 		return df->disconnected_f_op->release(inode, file);
444 	}
445 
446 	panic("%s(%p, %p) failed!", __func__, inode, file);
447 }
448 
snd_disconnect_poll(struct file * file,poll_table * wait)449 static __poll_t snd_disconnect_poll(struct file * file, poll_table * wait)
450 {
451 	return EPOLLERR | EPOLLNVAL;
452 }
453 
snd_disconnect_ioctl(struct file * file,unsigned int cmd,unsigned long arg)454 static long snd_disconnect_ioctl(struct file *file,
455 				 unsigned int cmd, unsigned long arg)
456 {
457 	return -ENODEV;
458 }
459 
snd_disconnect_mmap(struct file * file,struct vm_area_struct * vma)460 static int snd_disconnect_mmap(struct file *file, struct vm_area_struct *vma)
461 {
462 	return -ENODEV;
463 }
464 
snd_disconnect_fasync(int fd,struct file * file,int on)465 static int snd_disconnect_fasync(int fd, struct file *file, int on)
466 {
467 	return -ENODEV;
468 }
469 
470 static const struct file_operations snd_shutdown_f_ops =
471 {
472 	.owner = 	THIS_MODULE,
473 	.llseek =	snd_disconnect_llseek,
474 	.read = 	snd_disconnect_read,
475 	.write =	snd_disconnect_write,
476 	.release =	snd_disconnect_release,
477 	.poll =		snd_disconnect_poll,
478 	.unlocked_ioctl = snd_disconnect_ioctl,
479 #ifdef CONFIG_COMPAT
480 	.compat_ioctl = snd_disconnect_ioctl,
481 #endif
482 	.mmap =		snd_disconnect_mmap,
483 	.fasync =	snd_disconnect_fasync
484 };
485 
486 /**
487  *  snd_card_disconnect - disconnect all APIs from the file-operations (user space)
488  *  @card: soundcard structure
489  *
490  *  Disconnects all APIs from the file-operations (user space).
491  *
492  *  Return: Zero, otherwise a negative error code.
493  *
494  *  Note: The current implementation replaces all active file->f_op with special
495  *        dummy file operations (they do nothing except release).
496  */
snd_card_disconnect(struct snd_card * card)497 void snd_card_disconnect(struct snd_card *card)
498 {
499 	struct snd_monitor_file *mfile;
500 
501 	if (!card)
502 		return;
503 
504 	spin_lock(&card->files_lock);
505 	if (card->shutdown) {
506 		spin_unlock(&card->files_lock);
507 		return;
508 	}
509 	card->shutdown = 1;
510 
511 	/* replace file->f_op with special dummy operations */
512 	list_for_each_entry(mfile, &card->files_list, list) {
513 		/* it's critical part, use endless loop */
514 		/* we have no room to fail */
515 		mfile->disconnected_f_op = mfile->file->f_op;
516 
517 		spin_lock(&shutdown_lock);
518 		list_add(&mfile->shutdown_list, &shutdown_files);
519 		spin_unlock(&shutdown_lock);
520 
521 		mfile->file->f_op = &snd_shutdown_f_ops;
522 		fops_get(mfile->file->f_op);
523 	}
524 	spin_unlock(&card->files_lock);
525 
526 	/* notify all connected devices about disconnection */
527 	/* at this point, they cannot respond to any calls except release() */
528 
529 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
530 	if (snd_mixer_oss_notify_callback)
531 		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_DISCONNECT);
532 #endif
533 
534 	/* notify all devices that we are disconnected */
535 	snd_device_disconnect_all(card);
536 
537 	if (card->sync_irq > 0)
538 		synchronize_irq(card->sync_irq);
539 
540 	snd_info_card_disconnect(card);
541 	if (card->registered) {
542 		device_del(&card->card_dev);
543 		card->registered = false;
544 	}
545 
546 	/* disable fops (user space) operations for ALSA API */
547 	mutex_lock(&snd_card_mutex);
548 	snd_cards[card->number] = NULL;
549 	clear_bit(card->number, snd_cards_lock);
550 	mutex_unlock(&snd_card_mutex);
551 
552 #ifdef CONFIG_PM
553 	wake_up(&card->power_sleep);
554 	snd_power_sync_ref(card);
555 #endif
556 }
557 EXPORT_SYMBOL(snd_card_disconnect);
558 
559 /**
560  * snd_card_disconnect_sync - disconnect card and wait until files get closed
561  * @card: card object to disconnect
562  *
563  * This calls snd_card_disconnect() for disconnecting all belonging components
564  * and waits until all pending files get closed.
565  * It assures that all accesses from user-space finished so that the driver
566  * can release its resources gracefully.
567  */
snd_card_disconnect_sync(struct snd_card * card)568 void snd_card_disconnect_sync(struct snd_card *card)
569 {
570 	snd_card_disconnect(card);
571 
572 	spin_lock_irq(&card->files_lock);
573 	wait_event_lock_irq(card->remove_sleep,
574 			    list_empty(&card->files_list),
575 			    card->files_lock);
576 	spin_unlock_irq(&card->files_lock);
577 }
578 EXPORT_SYMBOL_GPL(snd_card_disconnect_sync);
579 
snd_card_do_free(struct snd_card * card)580 static int snd_card_do_free(struct snd_card *card)
581 {
582 	card->releasing = true;
583 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
584 	if (snd_mixer_oss_notify_callback)
585 		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_FREE);
586 #endif
587 	snd_device_free_all(card);
588 	if (card->private_free)
589 		card->private_free(card);
590 	if (snd_info_card_free(card) < 0) {
591 		dev_warn(card->dev, "unable to free card info\n");
592 		/* Not fatal error */
593 	}
594 #ifdef CONFIG_SND_DEBUG
595 	debugfs_remove(card->debugfs_root);
596 	card->debugfs_root = NULL;
597 #endif
598 	if (card->release_completion)
599 		complete(card->release_completion);
600 	if (!card->managed)
601 		kfree(card);
602 	return 0;
603 }
604 
605 /**
606  * snd_card_free_when_closed - Disconnect the card, free it later eventually
607  * @card: soundcard structure
608  *
609  * Unlike snd_card_free(), this function doesn't try to release the card
610  * resource immediately, but tries to disconnect at first.  When the card
611  * is still in use, the function returns before freeing the resources.
612  * The card resources will be freed when the refcount gets to zero.
613  *
614  * Return: zero if successful, or a negative error code
615  */
snd_card_free_when_closed(struct snd_card * card)616 void snd_card_free_when_closed(struct snd_card *card)
617 {
618 	if (!card)
619 		return;
620 
621 	snd_card_disconnect(card);
622 	put_device(&card->card_dev);
623 	return;
624 }
625 EXPORT_SYMBOL(snd_card_free_when_closed);
626 
627 /**
628  * snd_card_free - frees given soundcard structure
629  * @card: soundcard structure
630  *
631  * This function releases the soundcard structure and the all assigned
632  * devices automatically.  That is, you don't have to release the devices
633  * by yourself.
634  *
635  * This function waits until the all resources are properly released.
636  *
637  * Return: Zero. Frees all associated devices and frees the control
638  * interface associated to given soundcard.
639  */
snd_card_free(struct snd_card * card)640 void snd_card_free(struct snd_card *card)
641 {
642 	DECLARE_COMPLETION_ONSTACK(released);
643 
644 	/* The call of snd_card_free() is allowed from various code paths;
645 	 * a manual call from the driver and the call via devres_free, and
646 	 * we need to avoid double-free. Moreover, the release via devres
647 	 * may call snd_card_free() twice due to its nature, we need to have
648 	 * the check here at the beginning.
649 	 */
650 	if (card->releasing)
651 		return;
652 
653 	card->release_completion = &released;
654 	snd_card_free_when_closed(card);
655 
656 	/* wait, until all devices are ready for the free operation */
657 	wait_for_completion(&released);
658 }
659 EXPORT_SYMBOL(snd_card_free);
660 
661 /* retrieve the last word of shortname or longname */
retrieve_id_from_card_name(const char * name)662 static const char *retrieve_id_from_card_name(const char *name)
663 {
664 	const char *spos = name;
665 
666 	while (*name) {
667 		if (isspace(*name) && isalnum(name[1]))
668 			spos = name + 1;
669 		name++;
670 	}
671 	return spos;
672 }
673 
674 /* return true if the given id string doesn't conflict any other card ids */
card_id_ok(struct snd_card * card,const char * id)675 static bool card_id_ok(struct snd_card *card, const char *id)
676 {
677 	int i;
678 	if (!snd_info_check_reserved_words(id))
679 		return false;
680 	for (i = 0; i < snd_ecards_limit; i++) {
681 		if (snd_cards[i] && snd_cards[i] != card &&
682 		    !strcmp(snd_cards[i]->id, id))
683 			return false;
684 	}
685 	return true;
686 }
687 
688 /* copy to card->id only with valid letters from nid */
copy_valid_id_string(struct snd_card * card,const char * src,const char * nid)689 static void copy_valid_id_string(struct snd_card *card, const char *src,
690 				 const char *nid)
691 {
692 	char *id = card->id;
693 
694 	while (*nid && !isalnum(*nid))
695 		nid++;
696 	if (isdigit(*nid))
697 		*id++ = isalpha(*src) ? *src : 'D';
698 	while (*nid && (size_t)(id - card->id) < sizeof(card->id) - 1) {
699 		if (isalnum(*nid))
700 			*id++ = *nid;
701 		nid++;
702 	}
703 	*id = 0;
704 }
705 
706 /* Set card->id from the given string
707  * If the string conflicts with other ids, add a suffix to make it unique.
708  */
snd_card_set_id_no_lock(struct snd_card * card,const char * src,const char * nid)709 static void snd_card_set_id_no_lock(struct snd_card *card, const char *src,
710 				    const char *nid)
711 {
712 	int len, loops;
713 	bool is_default = false;
714 	char *id;
715 
716 	copy_valid_id_string(card, src, nid);
717 	id = card->id;
718 
719  again:
720 	/* use "Default" for obviously invalid strings
721 	 * ("card" conflicts with proc directories)
722 	 */
723 	if (!*id || !strncmp(id, "card", 4)) {
724 		strcpy(id, "Default");
725 		is_default = true;
726 	}
727 
728 	len = strlen(id);
729 	for (loops = 0; loops < SNDRV_CARDS; loops++) {
730 		char *spos;
731 		char sfxstr[5]; /* "_012" */
732 		int sfxlen;
733 
734 		if (card_id_ok(card, id))
735 			return; /* OK */
736 
737 		/* Add _XYZ suffix */
738 		sprintf(sfxstr, "_%X", loops + 1);
739 		sfxlen = strlen(sfxstr);
740 		if (len + sfxlen >= sizeof(card->id))
741 			spos = id + sizeof(card->id) - sfxlen - 1;
742 		else
743 			spos = id + len;
744 		strcpy(spos, sfxstr);
745 	}
746 	/* fallback to the default id */
747 	if (!is_default) {
748 		*id = 0;
749 		goto again;
750 	}
751 	/* last resort... */
752 	dev_err(card->dev, "unable to set card id (%s)\n", id);
753 	if (card->proc_root->name)
754 		strscpy(card->id, card->proc_root->name, sizeof(card->id));
755 }
756 
757 /**
758  *  snd_card_set_id - set card identification name
759  *  @card: soundcard structure
760  *  @nid: new identification string
761  *
762  *  This function sets the card identification and checks for name
763  *  collisions.
764  */
snd_card_set_id(struct snd_card * card,const char * nid)765 void snd_card_set_id(struct snd_card *card, const char *nid)
766 {
767 	/* check if user specified own card->id */
768 	if (card->id[0] != '\0')
769 		return;
770 	mutex_lock(&snd_card_mutex);
771 	snd_card_set_id_no_lock(card, nid, nid);
772 	mutex_unlock(&snd_card_mutex);
773 }
774 EXPORT_SYMBOL(snd_card_set_id);
775 
id_show(struct device * dev,struct device_attribute * attr,char * buf)776 static ssize_t id_show(struct device *dev,
777 		       struct device_attribute *attr, char *buf)
778 {
779 	struct snd_card *card = container_of(dev, struct snd_card, card_dev);
780 	return sysfs_emit(buf, "%s\n", card->id);
781 }
782 
id_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)783 static ssize_t id_store(struct device *dev, struct device_attribute *attr,
784 			const char *buf, size_t count)
785 {
786 	struct snd_card *card = container_of(dev, struct snd_card, card_dev);
787 	char buf1[sizeof(card->id)];
788 	size_t copy = count > sizeof(card->id) - 1 ?
789 					sizeof(card->id) - 1 : count;
790 	size_t idx;
791 	int c;
792 
793 	for (idx = 0; idx < copy; idx++) {
794 		c = buf[idx];
795 		if (!isalnum(c) && c != '_' && c != '-')
796 			return -EINVAL;
797 	}
798 	memcpy(buf1, buf, copy);
799 	buf1[copy] = '\0';
800 	mutex_lock(&snd_card_mutex);
801 	if (!card_id_ok(NULL, buf1)) {
802 		mutex_unlock(&snd_card_mutex);
803 		return -EEXIST;
804 	}
805 	strcpy(card->id, buf1);
806 	snd_info_card_id_change(card);
807 	mutex_unlock(&snd_card_mutex);
808 
809 	return count;
810 }
811 
812 static DEVICE_ATTR_RW(id);
813 
number_show(struct device * dev,struct device_attribute * attr,char * buf)814 static ssize_t number_show(struct device *dev,
815 			   struct device_attribute *attr, char *buf)
816 {
817 	struct snd_card *card = container_of(dev, struct snd_card, card_dev);
818 	return sysfs_emit(buf, "%i\n", card->number);
819 }
820 
821 static DEVICE_ATTR_RO(number);
822 
823 static struct attribute *card_dev_attrs[] = {
824 	&dev_attr_id.attr,
825 	&dev_attr_number.attr,
826 	NULL
827 };
828 
829 static const struct attribute_group card_dev_attr_group = {
830 	.attrs	= card_dev_attrs,
831 };
832 
833 /**
834  * snd_card_add_dev_attr - Append a new sysfs attribute group to card
835  * @card: card instance
836  * @group: attribute group to append
837  *
838  * Return: zero if successful, or a negative error code
839  */
snd_card_add_dev_attr(struct snd_card * card,const struct attribute_group * group)840 int snd_card_add_dev_attr(struct snd_card *card,
841 			  const struct attribute_group *group)
842 {
843 	int i;
844 
845 	/* loop for (arraysize-1) here to keep NULL at the last entry */
846 	for (i = 0; i < ARRAY_SIZE(card->dev_groups) - 1; i++) {
847 		if (!card->dev_groups[i]) {
848 			card->dev_groups[i] = group;
849 			return 0;
850 		}
851 	}
852 
853 	dev_err(card->dev, "Too many groups assigned\n");
854 	return -ENOSPC;
855 }
856 EXPORT_SYMBOL_GPL(snd_card_add_dev_attr);
857 
trigger_card_free(void * data)858 static void trigger_card_free(void *data)
859 {
860 	snd_card_free(data);
861 }
862 
863 /**
864  *  snd_card_register - register the soundcard
865  *  @card: soundcard structure
866  *
867  *  This function registers all the devices assigned to the soundcard.
868  *  Until calling this, the ALSA control interface is blocked from the
869  *  external accesses.  Thus, you should call this function at the end
870  *  of the initialization of the card.
871  *
872  *  Return: Zero otherwise a negative error code if the registration failed.
873  */
snd_card_register(struct snd_card * card)874 int snd_card_register(struct snd_card *card)
875 {
876 	int err;
877 
878 	if (snd_BUG_ON(!card))
879 		return -EINVAL;
880 
881 	if (!card->registered) {
882 		err = device_add(&card->card_dev);
883 		if (err < 0)
884 			return err;
885 		card->registered = true;
886 	} else {
887 		if (card->managed)
888 			devm_remove_action(card->dev, trigger_card_free, card);
889 	}
890 
891 	if (card->managed) {
892 		err = devm_add_action(card->dev, trigger_card_free, card);
893 		if (err < 0)
894 			return err;
895 	}
896 
897 	err = snd_device_register_all(card);
898 	if (err < 0)
899 		return err;
900 	mutex_lock(&snd_card_mutex);
901 	if (snd_cards[card->number]) {
902 		/* already registered */
903 		mutex_unlock(&snd_card_mutex);
904 		return snd_info_card_register(card); /* register pending info */
905 	}
906 	if (*card->id) {
907 		/* make a unique id name from the given string */
908 		char tmpid[sizeof(card->id)];
909 		memcpy(tmpid, card->id, sizeof(card->id));
910 		snd_card_set_id_no_lock(card, tmpid, tmpid);
911 	} else {
912 		/* create an id from either shortname or longname */
913 		const char *src;
914 		src = *card->shortname ? card->shortname : card->longname;
915 		snd_card_set_id_no_lock(card, src,
916 					retrieve_id_from_card_name(src));
917 	}
918 	snd_cards[card->number] = card;
919 	mutex_unlock(&snd_card_mutex);
920 	err = snd_info_card_register(card);
921 	if (err < 0)
922 		return err;
923 
924 #if IS_ENABLED(CONFIG_SND_MIXER_OSS)
925 	if (snd_mixer_oss_notify_callback)
926 		snd_mixer_oss_notify_callback(card, SND_MIXER_OSS_NOTIFY_REGISTER);
927 #endif
928 	return 0;
929 }
930 EXPORT_SYMBOL(snd_card_register);
931 
932 #ifdef CONFIG_SND_PROC_FS
snd_card_info_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)933 static void snd_card_info_read(struct snd_info_entry *entry,
934 			       struct snd_info_buffer *buffer)
935 {
936 	int idx, count;
937 	struct snd_card *card;
938 
939 	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
940 		mutex_lock(&snd_card_mutex);
941 		card = snd_cards[idx];
942 		if (card) {
943 			count++;
944 			snd_iprintf(buffer, "%2i [%-15s]: %s - %s\n",
945 					idx,
946 					card->id,
947 					card->driver,
948 					card->shortname);
949 			snd_iprintf(buffer, "                      %s\n",
950 					card->longname);
951 		}
952 		mutex_unlock(&snd_card_mutex);
953 	}
954 	if (!count)
955 		snd_iprintf(buffer, "--- no soundcards ---\n");
956 }
957 
958 #ifdef CONFIG_SND_OSSEMUL
snd_card_info_read_oss(struct snd_info_buffer * buffer)959 void snd_card_info_read_oss(struct snd_info_buffer *buffer)
960 {
961 	int idx, count;
962 	struct snd_card *card;
963 
964 	for (idx = count = 0; idx < SNDRV_CARDS; idx++) {
965 		mutex_lock(&snd_card_mutex);
966 		card = snd_cards[idx];
967 		if (card) {
968 			count++;
969 			snd_iprintf(buffer, "%s\n", card->longname);
970 		}
971 		mutex_unlock(&snd_card_mutex);
972 	}
973 	if (!count) {
974 		snd_iprintf(buffer, "--- no soundcards ---\n");
975 	}
976 }
977 
978 #endif
979 
980 #ifdef MODULE
snd_card_module_info_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)981 static void snd_card_module_info_read(struct snd_info_entry *entry,
982 				      struct snd_info_buffer *buffer)
983 {
984 	int idx;
985 	struct snd_card *card;
986 
987 	for (idx = 0; idx < SNDRV_CARDS; idx++) {
988 		mutex_lock(&snd_card_mutex);
989 		card = snd_cards[idx];
990 		if (card)
991 			snd_iprintf(buffer, "%2i %s\n",
992 				    idx, card->module->name);
993 		mutex_unlock(&snd_card_mutex);
994 	}
995 }
996 #endif
997 
snd_card_info_init(void)998 int __init snd_card_info_init(void)
999 {
1000 	struct snd_info_entry *entry;
1001 
1002 	entry = snd_info_create_module_entry(THIS_MODULE, "cards", NULL);
1003 	if (! entry)
1004 		return -ENOMEM;
1005 	entry->c.text.read = snd_card_info_read;
1006 	if (snd_info_register(entry) < 0)
1007 		return -ENOMEM; /* freed in error path */
1008 
1009 #ifdef MODULE
1010 	entry = snd_info_create_module_entry(THIS_MODULE, "modules", NULL);
1011 	if (!entry)
1012 		return -ENOMEM;
1013 	entry->c.text.read = snd_card_module_info_read;
1014 	if (snd_info_register(entry) < 0)
1015 		return -ENOMEM; /* freed in error path */
1016 #endif
1017 
1018 	return 0;
1019 }
1020 #endif /* CONFIG_SND_PROC_FS */
1021 
1022 /**
1023  *  snd_component_add - add a component string
1024  *  @card: soundcard structure
1025  *  @component: the component id string
1026  *
1027  *  This function adds the component id string to the supported list.
1028  *  The component can be referred from the alsa-lib.
1029  *
1030  *  Return: Zero otherwise a negative error code.
1031  */
1032 
snd_component_add(struct snd_card * card,const char * component)1033 int snd_component_add(struct snd_card *card, const char *component)
1034 {
1035 	char *ptr;
1036 	int len = strlen(component);
1037 
1038 	ptr = strstr(card->components, component);
1039 	if (ptr != NULL) {
1040 		if (ptr[len] == '\0' || ptr[len] == ' ')	/* already there */
1041 			return 1;
1042 	}
1043 	if (strlen(card->components) + 1 + len + 1 > sizeof(card->components)) {
1044 		snd_BUG();
1045 		return -ENOMEM;
1046 	}
1047 	if (card->components[0] != '\0')
1048 		strcat(card->components, " ");
1049 	strcat(card->components, component);
1050 	return 0;
1051 }
1052 EXPORT_SYMBOL(snd_component_add);
1053 
1054 /**
1055  *  snd_card_file_add - add the file to the file list of the card
1056  *  @card: soundcard structure
1057  *  @file: file pointer
1058  *
1059  *  This function adds the file to the file linked-list of the card.
1060  *  This linked-list is used to keep tracking the connection state,
1061  *  and to avoid the release of busy resources by hotplug.
1062  *
1063  *  Return: zero or a negative error code.
1064  */
snd_card_file_add(struct snd_card * card,struct file * file)1065 int snd_card_file_add(struct snd_card *card, struct file *file)
1066 {
1067 	struct snd_monitor_file *mfile;
1068 
1069 	mfile = kmalloc(sizeof(*mfile), GFP_KERNEL);
1070 	if (mfile == NULL)
1071 		return -ENOMEM;
1072 	mfile->file = file;
1073 	mfile->disconnected_f_op = NULL;
1074 	INIT_LIST_HEAD(&mfile->shutdown_list);
1075 	spin_lock(&card->files_lock);
1076 	if (card->shutdown) {
1077 		spin_unlock(&card->files_lock);
1078 		kfree(mfile);
1079 		return -ENODEV;
1080 	}
1081 	list_add(&mfile->list, &card->files_list);
1082 	get_device(&card->card_dev);
1083 	spin_unlock(&card->files_lock);
1084 	return 0;
1085 }
1086 EXPORT_SYMBOL(snd_card_file_add);
1087 
1088 /**
1089  *  snd_card_file_remove - remove the file from the file list
1090  *  @card: soundcard structure
1091  *  @file: file pointer
1092  *
1093  *  This function removes the file formerly added to the card via
1094  *  snd_card_file_add() function.
1095  *  If all files are removed and snd_card_free_when_closed() was
1096  *  called beforehand, it processes the pending release of
1097  *  resources.
1098  *
1099  *  Return: Zero or a negative error code.
1100  */
snd_card_file_remove(struct snd_card * card,struct file * file)1101 int snd_card_file_remove(struct snd_card *card, struct file *file)
1102 {
1103 	struct snd_monitor_file *mfile, *found = NULL;
1104 
1105 	spin_lock(&card->files_lock);
1106 	list_for_each_entry(mfile, &card->files_list, list) {
1107 		if (mfile->file == file) {
1108 			list_del(&mfile->list);
1109 			spin_lock(&shutdown_lock);
1110 			list_del(&mfile->shutdown_list);
1111 			spin_unlock(&shutdown_lock);
1112 			if (mfile->disconnected_f_op)
1113 				fops_put(mfile->disconnected_f_op);
1114 			found = mfile;
1115 			break;
1116 		}
1117 	}
1118 	if (list_empty(&card->files_list))
1119 		wake_up_all(&card->remove_sleep);
1120 	spin_unlock(&card->files_lock);
1121 	if (!found) {
1122 		dev_err(card->dev, "card file remove problem (%p)\n", file);
1123 		return -ENOENT;
1124 	}
1125 	kfree(found);
1126 	put_device(&card->card_dev);
1127 	return 0;
1128 }
1129 EXPORT_SYMBOL(snd_card_file_remove);
1130 
1131 #ifdef CONFIG_PM
1132 /**
1133  * snd_power_ref_and_wait - wait until the card gets powered up
1134  * @card: soundcard structure
1135  *
1136  * Take the power_ref reference count of the given card, and
1137  * wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
1138  * The refcount is down again while sleeping until power-up, hence this
1139  * function can be used for syncing the floating control ops accesses,
1140  * typically around calling control ops.
1141  *
1142  * The caller needs to pull down the refcount via snd_power_unref() later
1143  * no matter whether the error is returned from this function or not.
1144  *
1145  * Return: Zero if successful, or a negative error code.
1146  */
snd_power_ref_and_wait(struct snd_card * card)1147 int snd_power_ref_and_wait(struct snd_card *card)
1148 {
1149 	snd_power_ref(card);
1150 	if (snd_power_get_state(card) == SNDRV_CTL_POWER_D0)
1151 		return 0;
1152 	wait_event_cmd(card->power_sleep,
1153 		       card->shutdown ||
1154 		       snd_power_get_state(card) == SNDRV_CTL_POWER_D0,
1155 		       snd_power_unref(card), snd_power_ref(card));
1156 	return card->shutdown ? -ENODEV : 0;
1157 }
1158 EXPORT_SYMBOL_GPL(snd_power_ref_and_wait);
1159 
1160 /**
1161  * snd_power_wait - wait until the card gets powered up (old form)
1162  * @card: soundcard structure
1163  *
1164  * Wait until the card gets powered up to SNDRV_CTL_POWER_D0 state.
1165  *
1166  * Return: Zero if successful, or a negative error code.
1167  */
snd_power_wait(struct snd_card * card)1168 int snd_power_wait(struct snd_card *card)
1169 {
1170 	int ret;
1171 
1172 	ret = snd_power_ref_and_wait(card);
1173 	snd_power_unref(card);
1174 	return ret;
1175 }
1176 EXPORT_SYMBOL(snd_power_wait);
1177 #endif /* CONFIG_PM */
1178