1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *  Information interface for ALSA driver
  4 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
  5 */
  6
  7#include <linux/init.h>
  8#include <linux/time.h>
  9#include <linux/mm.h>
 10#include <linux/slab.h>
 11#include <linux/string.h>
 12#include <linux/module.h>
 13#include <sound/core.h>
 14#include <sound/minors.h>
 15#include <sound/info.h>
 16#include <linux/utsname.h>
 17#include <linux/proc_fs.h>
 18#include <linux/mutex.h>
 19#include <stdarg.h>
 20
 21int snd_info_check_reserved_words(const char *str)
 22{
 23	static char *reserved[] =
 24	{
 25		"version",
 26		"meminfo",
 27		"memdebug",
 28		"detect",
 29		"devices",
 30		"oss",
 31		"cards",
 32		"timers",
 33		"synth",
 34		"pcm",
 35		"seq",
 36		NULL
 37	};
 38	char **xstr = reserved;
 39
 40	while (*xstr) {
 41		if (!strcmp(*xstr, str))
 42			return 0;
 43		xstr++;
 44	}
 45	if (!strncmp(str, "card", 4))
 46		return 0;
 47	return 1;
 48}
 49
 50static DEFINE_MUTEX(info_mutex);
 51
 52struct snd_info_private_data {
 53	struct snd_info_buffer *rbuffer;
 54	struct snd_info_buffer *wbuffer;
 55	struct snd_info_entry *entry;
 56	void *file_private_data;
 57};
 58
 59static int snd_info_version_init(void);
 60static void snd_info_disconnect(struct snd_info_entry *entry);
 61
 62/*
 63
 64 */
 65
 66static struct snd_info_entry *snd_proc_root;
 67struct snd_info_entry *snd_seq_root;
 68EXPORT_SYMBOL(snd_seq_root);
 69
 70#ifdef CONFIG_SND_OSSEMUL
 71struct snd_info_entry *snd_oss_root;
 72#endif
 73
 74static int alloc_info_private(struct snd_info_entry *entry,
 75			      struct snd_info_private_data **ret)
 76{
 77	struct snd_info_private_data *data;
 78
 79	if (!entry || !entry->p)
 80		return -ENODEV;
 81	if (!try_module_get(entry->module))
 82		return -EFAULT;
 83	data = kzalloc(sizeof(*data), GFP_KERNEL);
 84	if (!data) {
 85		module_put(entry->module);
 86		return -ENOMEM;
 87	}
 88	data->entry = entry;
 89	*ret = data;
 90	return 0;
 91}
 92
 93static bool valid_pos(loff_t pos, size_t count)
 94{
 95	if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
 96		return false;
 97	if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
 98		return false;
 99	return true;
100}
101
102/*
103 * file ops for binary proc files
104 */
105static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
106{
107	struct snd_info_private_data *data;
108	struct snd_info_entry *entry;
109	loff_t ret = -EINVAL, size;
110
111	data = file->private_data;
112	entry = data->entry;
113	mutex_lock(&entry->access);
114	if (entry->c.ops->llseek) {
115		offset = entry->c.ops->llseek(entry,
116					      data->file_private_data,
117					      file, offset, orig);
118		goto out;
119	}
120
121	size = entry->size;
122	switch (orig) {
123	case SEEK_SET:
124		break;
125	case SEEK_CUR:
126		offset += file->f_pos;
127		break;
128	case SEEK_END:
129		if (!size)
130			goto out;
131		offset += size;
132		break;
133	default:
134		goto out;
135	}
136	if (offset < 0)
137		goto out;
138	if (size && offset > size)
139		offset = size;
140	file->f_pos = offset;
141	ret = offset;
142 out:
143	mutex_unlock(&entry->access);
144	return ret;
145}
146
147static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
148				   size_t count, loff_t * offset)
149{
150	struct snd_info_private_data *data = file->private_data;
151	struct snd_info_entry *entry = data->entry;
152	size_t size;
153	loff_t pos;
154
155	pos = *offset;
156	if (!valid_pos(pos, count))
157		return -EIO;
158	if (pos >= entry->size)
159		return 0;
160	size = entry->size - pos;
161	size = min(count, size);
162	size = entry->c.ops->read(entry, data->file_private_data,
163				  file, buffer, size, pos);
164	if ((ssize_t) size > 0)
165		*offset = pos + size;
166	return size;
167}
168
169static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
170				    size_t count, loff_t * offset)
171{
172	struct snd_info_private_data *data = file->private_data;
173	struct snd_info_entry *entry = data->entry;
174	ssize_t size = 0;
175	loff_t pos;
176
177	pos = *offset;
178	if (!valid_pos(pos, count))
179		return -EIO;
180	if (count > 0) {
181		size_t maxsize = entry->size - pos;
182		count = min(count, maxsize);
183		size = entry->c.ops->write(entry, data->file_private_data,
184					   file, buffer, count, pos);
185	}
186	if (size > 0)
187		*offset = pos + size;
188	return size;
189}
190
191static __poll_t snd_info_entry_poll(struct file *file, poll_table *wait)
192{
193	struct snd_info_private_data *data = file->private_data;
194	struct snd_info_entry *entry = data->entry;
195	__poll_t mask = 0;
196
197	if (entry->c.ops->poll)
198		return entry->c.ops->poll(entry,
199					  data->file_private_data,
200					  file, wait);
201	if (entry->c.ops->read)
202		mask |= EPOLLIN | EPOLLRDNORM;
203	if (entry->c.ops->write)
204		mask |= EPOLLOUT | EPOLLWRNORM;
205	return mask;
206}
207
208static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
209				unsigned long arg)
210{
211	struct snd_info_private_data *data = file->private_data;
212	struct snd_info_entry *entry = data->entry;
213
214	if (!entry->c.ops->ioctl)
215		return -ENOTTY;
216	return entry->c.ops->ioctl(entry, data->file_private_data,
217				   file, cmd, arg);
218}
219
220static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
221{
222	struct inode *inode = file_inode(file);
223	struct snd_info_private_data *data;
224	struct snd_info_entry *entry;
225
226	data = file->private_data;
227	if (data == NULL)
228		return 0;
229	entry = data->entry;
230	if (!entry->c.ops->mmap)
231		return -ENXIO;
232	return entry->c.ops->mmap(entry, data->file_private_data,
233				  inode, file, vma);
234}
235
236static int snd_info_entry_open(struct inode *inode, struct file *file)
237{
238	struct snd_info_entry *entry = PDE_DATA(inode);
239	struct snd_info_private_data *data;
240	int mode, err;
241
242	mutex_lock(&info_mutex);
243	err = alloc_info_private(entry, &data);
244	if (err < 0)
245		goto unlock;
246
247	mode = file->f_flags & O_ACCMODE;
248	if (((mode == O_RDONLY || mode == O_RDWR) && !entry->c.ops->read) ||
249	    ((mode == O_WRONLY || mode == O_RDWR) && !entry->c.ops->write)) {
250		err = -ENODEV;
251		goto error;
252	}
253
254	if (entry->c.ops->open) {
255		err = entry->c.ops->open(entry, mode, &data->file_private_data);
256		if (err < 0)
257			goto error;
258	}
259
260	file->private_data = data;
261	mutex_unlock(&info_mutex);
262	return 0;
263
264 error:
265	kfree(data);
266	module_put(entry->module);
267 unlock:
268	mutex_unlock(&info_mutex);
269	return err;
270}
271
272static int snd_info_entry_release(struct inode *inode, struct file *file)
273{
274	struct snd_info_private_data *data = file->private_data;
275	struct snd_info_entry *entry = data->entry;
276
277	if (entry->c.ops->release)
278		entry->c.ops->release(entry, file->f_flags & O_ACCMODE,
279				      data->file_private_data);
280	module_put(entry->module);
281	kfree(data);
282	return 0;
283}
284
285static const struct file_operations snd_info_entry_operations =
286{
287	.owner =		THIS_MODULE,
288	.llseek =		snd_info_entry_llseek,
289	.read =			snd_info_entry_read,
290	.write =		snd_info_entry_write,
291	.poll =			snd_info_entry_poll,
292	.unlocked_ioctl =	snd_info_entry_ioctl,
293	.mmap =			snd_info_entry_mmap,
294	.open =			snd_info_entry_open,
295	.release =		snd_info_entry_release,
296};
297
298/*
299 * file ops for text proc files
300 */
301static ssize_t snd_info_text_entry_write(struct file *file,
302					 const char __user *buffer,
303					 size_t count, loff_t *offset)
304{
305	struct seq_file *m = file->private_data;
306	struct snd_info_private_data *data = m->private;
307	struct snd_info_entry *entry = data->entry;
308	struct snd_info_buffer *buf;
309	loff_t pos;
310	size_t next;
311	int err = 0;
312
313	if (!entry->c.text.write)
314		return -EIO;
315	pos = *offset;
316	if (!valid_pos(pos, count))
317		return -EIO;
318	next = pos + count;
319	/* don't handle too large text inputs */
320	if (next > 16 * 1024)
321		return -EIO;
322	mutex_lock(&entry->access);
323	buf = data->wbuffer;
324	if (!buf) {
325		data->wbuffer = buf = kzalloc(sizeof(*buf), GFP_KERNEL);
326		if (!buf) {
327			err = -ENOMEM;
328			goto error;
329		}
330	}
331	if (next > buf->len) {
332		char *nbuf = kvzalloc(PAGE_ALIGN(next), GFP_KERNEL);
333		if (!nbuf) {
334			err = -ENOMEM;
335			goto error;
336		}
337		kvfree(buf->buffer);
338		buf->buffer = nbuf;
339		buf->len = PAGE_ALIGN(next);
340	}
341	if (copy_from_user(buf->buffer + pos, buffer, count)) {
342		err = -EFAULT;
343		goto error;
344	}
345	buf->size = next;
346 error:
347	mutex_unlock(&entry->access);
348	if (err < 0)
349		return err;
350	*offset = next;
351	return count;
352}
353
354static int snd_info_seq_show(struct seq_file *seq, void *p)
355{
356	struct snd_info_private_data *data = seq->private;
357	struct snd_info_entry *entry = data->entry;
358
359	if (!entry->c.text.read) {
360		return -EIO;
361	} else {
362		data->rbuffer->buffer = (char *)seq; /* XXX hack! */
363		entry->c.text.read(entry, data->rbuffer);
364	}
365	return 0;
366}
367
368static int snd_info_text_entry_open(struct inode *inode, struct file *file)
369{
370	struct snd_info_entry *entry = PDE_DATA(inode);
371	struct snd_info_private_data *data;
372	int err;
373
374	mutex_lock(&info_mutex);
375	err = alloc_info_private(entry, &data);
376	if (err < 0)
377		goto unlock;
378
379	data->rbuffer = kzalloc(sizeof(*data->rbuffer), GFP_KERNEL);
380	if (!data->rbuffer) {
381		err = -ENOMEM;
382		goto error;
383	}
384	if (entry->size)
385		err = single_open_size(file, snd_info_seq_show, data,
386				       entry->size);
387	else
388		err = single_open(file, snd_info_seq_show, data);
389	if (err < 0)
390		goto error;
391	mutex_unlock(&info_mutex);
392	return 0;
393
394 error:
395	kfree(data->rbuffer);
396	kfree(data);
397	module_put(entry->module);
398 unlock:
399	mutex_unlock(&info_mutex);
400	return err;
401}
402
403static int snd_info_text_entry_release(struct inode *inode, struct file *file)
404{
405	struct seq_file *m = file->private_data;
406	struct snd_info_private_data *data = m->private;
407	struct snd_info_entry *entry = data->entry;
408
409	if (data->wbuffer && entry->c.text.write)
410		entry->c.text.write(entry, data->wbuffer);
411
412	single_release(inode, file);
413	kfree(data->rbuffer);
414	if (data->wbuffer) {
415		kvfree(data->wbuffer->buffer);
416		kfree(data->wbuffer);
417	}
418
419	module_put(entry->module);
420	kfree(data);
421	return 0;
422}
423
424static const struct file_operations snd_info_text_entry_ops =
425{
426	.owner =		THIS_MODULE,
427	.open =			snd_info_text_entry_open,
428	.release =		snd_info_text_entry_release,
429	.write =		snd_info_text_entry_write,
430	.llseek =		seq_lseek,
431	.read =			seq_read,
432};
433
434static struct snd_info_entry *create_subdir(struct module *mod,
435					    const char *name)
436{
437	struct snd_info_entry *entry;
438
439	entry = snd_info_create_module_entry(mod, name, NULL);
440	if (!entry)
441		return NULL;
442	entry->mode = S_IFDIR | 0555;
443	if (snd_info_register(entry) < 0) {
444		snd_info_free_entry(entry);
445		return NULL;
446	}
447	return entry;
448}
449
450static struct snd_info_entry *
451snd_info_create_entry(const char *name, struct snd_info_entry *parent,
452		      struct module *module);
453
454int __init snd_info_init(void)
455{
456	snd_proc_root = snd_info_create_entry("asound", NULL, THIS_MODULE);
457	if (!snd_proc_root)
458		return -ENOMEM;
459	snd_proc_root->mode = S_IFDIR | 0555;
460	snd_proc_root->p = proc_mkdir("asound", NULL);
461	if (!snd_proc_root->p)
462		goto error;
463#ifdef CONFIG_SND_OSSEMUL
464	snd_oss_root = create_subdir(THIS_MODULE, "oss");
465	if (!snd_oss_root)
466		goto error;
467#endif
468#if IS_ENABLED(CONFIG_SND_SEQUENCER)
469	snd_seq_root = create_subdir(THIS_MODULE, "seq");
470	if (!snd_seq_root)
471		goto error;
472#endif
473	if (snd_info_version_init() < 0 ||
474	    snd_minor_info_init() < 0 ||
475	    snd_minor_info_oss_init() < 0 ||
476	    snd_card_info_init() < 0 ||
477	    snd_info_minor_register() < 0)
478		goto error;
479	return 0;
480
481 error:
482	snd_info_free_entry(snd_proc_root);
483	return -ENOMEM;
484}
485
486int __exit snd_info_done(void)
487{
488	snd_info_free_entry(snd_proc_root);
489	return 0;
490}
491
492static void snd_card_id_read(struct snd_info_entry *entry,
493			     struct snd_info_buffer *buffer)
494{
495	struct snd_card *card = entry->private_data;
496
497	snd_iprintf(buffer, "%s\n", card->id);
498}
499
500/*
501 * create a card proc file
502 * called from init.c
503 */
504int snd_info_card_create(struct snd_card *card)
505{
506	char str[8];
507	struct snd_info_entry *entry;
508
509	if (snd_BUG_ON(!card))
510		return -ENXIO;
511
512	sprintf(str, "card%i", card->number);
513	entry = create_subdir(card->module, str);
514	if (!entry)
515		return -ENOMEM;
516	card->proc_root = entry;
517
518	return snd_card_ro_proc_new(card, "id", card, snd_card_id_read);
519}
520
521/*
522 * register the card proc file
523 * called from init.c
524 * can be called multiple times for reinitialization
525 */
526int snd_info_card_register(struct snd_card *card)
527{
528	struct proc_dir_entry *p;
529	int err;
530
531	if (snd_BUG_ON(!card))
532		return -ENXIO;
533
534	err = snd_info_register(card->proc_root);
535	if (err < 0)
536		return err;
537
538	if (!strcmp(card->id, card->proc_root->name))
539		return 0;
540
541	if (card->proc_root_link)
542		return 0;
543	p = proc_symlink(card->id, snd_proc_root->p, card->proc_root->name);
544	if (!p)
545		return -ENOMEM;
546	card->proc_root_link = p;
547	return 0;
548}
549
550/*
551 * called on card->id change
552 */
553void snd_info_card_id_change(struct snd_card *card)
554{
555	mutex_lock(&info_mutex);
556	if (card->proc_root_link) {
557		proc_remove(card->proc_root_link);
558		card->proc_root_link = NULL;
559	}
560	if (strcmp(card->id, card->proc_root->name))
561		card->proc_root_link = proc_symlink(card->id,
562						    snd_proc_root->p,
563						    card->proc_root->name);
564	mutex_unlock(&info_mutex);
565}
566
567/*
568 * de-register the card proc file
569 * called from init.c
570 */
571void snd_info_card_disconnect(struct snd_card *card)
572{
573	if (!card)
574		return;
575	mutex_lock(&info_mutex);
576	proc_remove(card->proc_root_link);
577	card->proc_root_link = NULL;
578	if (card->proc_root)
579		snd_info_disconnect(card->proc_root);
580	mutex_unlock(&info_mutex);
581}
582
583/*
584 * release the card proc file resources
585 * called from init.c
586 */
587int snd_info_card_free(struct snd_card *card)
588{
589	if (!card)
590		return 0;
591	snd_info_free_entry(card->proc_root);
592	card->proc_root = NULL;
593	return 0;
594}
595
596
597/**
598 * snd_info_get_line - read one line from the procfs buffer
599 * @buffer: the procfs buffer
600 * @line: the buffer to store
601 * @len: the max. buffer size
602 *
603 * Reads one line from the buffer and stores the string.
604 *
605 * Return: Zero if successful, or 1 if error or EOF.
606 */
607int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
608{
609	int c = -1;
610
611	if (snd_BUG_ON(!buffer || !buffer->buffer))
 
 
612		return 1;
613	if (len <= 0 || buffer->stop || buffer->error)
614		return 1;
615	while (!buffer->stop) {
616		c = buffer->buffer[buffer->curr++];
617		if (buffer->curr >= buffer->size)
618			buffer->stop = 1;
619		if (c == '\n')
620			break;
621		if (len > 1) {
622			len--;
623			*line++ = c;
624		}
625	}
626	*line = '\0';
627	return 0;
628}
629EXPORT_SYMBOL(snd_info_get_line);
630
631/**
632 * snd_info_get_str - parse a string token
633 * @dest: the buffer to store the string token
634 * @src: the original string
635 * @len: the max. length of token - 1
636 *
637 * Parses the original string and copy a token to the given
638 * string buffer.
639 *
640 * Return: The updated pointer of the original string so that
641 * it can be used for the next call.
642 */
643const char *snd_info_get_str(char *dest, const char *src, int len)
644{
645	int c;
646
647	while (*src == ' ' || *src == '\t')
648		src++;
649	if (*src == '"' || *src == '\'') {
650		c = *src++;
651		while (--len > 0 && *src && *src != c) {
652			*dest++ = *src++;
653		}
654		if (*src == c)
655			src++;
656	} else {
657		while (--len > 0 && *src && *src != ' ' && *src != '\t') {
658			*dest++ = *src++;
659		}
660	}
661	*dest = 0;
662	while (*src == ' ' || *src == '\t')
663		src++;
664	return src;
665}
666EXPORT_SYMBOL(snd_info_get_str);
667
668/*
669 * snd_info_create_entry - create an info entry
670 * @name: the proc file name
671 * @parent: the parent directory
672 *
673 * Creates an info entry with the given file name and initializes as
674 * the default state.
675 *
676 * Usually called from other functions such as
677 * snd_info_create_card_entry().
678 *
679 * Return: The pointer of the new instance, or %NULL on failure.
680 */
681static struct snd_info_entry *
682snd_info_create_entry(const char *name, struct snd_info_entry *parent,
683		      struct module *module)
684{
685	struct snd_info_entry *entry;
686	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
687	if (entry == NULL)
688		return NULL;
689	entry->name = kstrdup(name, GFP_KERNEL);
690	if (entry->name == NULL) {
691		kfree(entry);
692		return NULL;
693	}
694	entry->mode = S_IFREG | 0444;
695	entry->content = SNDRV_INFO_CONTENT_TEXT;
696	mutex_init(&entry->access);
697	INIT_LIST_HEAD(&entry->children);
698	INIT_LIST_HEAD(&entry->list);
699	entry->parent = parent;
700	entry->module = module;
701	if (parent) {
702		mutex_lock(&parent->access);
703		list_add_tail(&entry->list, &parent->children);
704		mutex_unlock(&parent->access);
705	}
706	return entry;
707}
708
709/**
710 * snd_info_create_module_entry - create an info entry for the given module
711 * @module: the module pointer
712 * @name: the file name
713 * @parent: the parent directory
714 *
715 * Creates a new info entry and assigns it to the given module.
716 *
717 * Return: The pointer of the new instance, or %NULL on failure.
718 */
719struct snd_info_entry *snd_info_create_module_entry(struct module * module,
720					       const char *name,
721					       struct snd_info_entry *parent)
722{
723	if (!parent)
724		parent = snd_proc_root;
725	return snd_info_create_entry(name, parent, module);
726}
727EXPORT_SYMBOL(snd_info_create_module_entry);
728
729/**
730 * snd_info_create_card_entry - create an info entry for the given card
731 * @card: the card instance
732 * @name: the file name
733 * @parent: the parent directory
734 *
735 * Creates a new info entry and assigns it to the given card.
736 *
737 * Return: The pointer of the new instance, or %NULL on failure.
738 */
739struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
740					     const char *name,
741					     struct snd_info_entry * parent)
742{
743	if (!parent)
744		parent = card->proc_root;
745	return snd_info_create_entry(name, parent, card->module);
746}
747EXPORT_SYMBOL(snd_info_create_card_entry);
748
749static void snd_info_disconnect(struct snd_info_entry *entry)
750{
751	struct snd_info_entry *p;
752
753	if (!entry->p)
754		return;
755	list_for_each_entry(p, &entry->children, list)
756		snd_info_disconnect(p);
757	proc_remove(entry->p);
758	entry->p = NULL;
759}
760
761/**
762 * snd_info_free_entry - release the info entry
763 * @entry: the info entry
764 *
765 * Releases the info entry.
766 */
767void snd_info_free_entry(struct snd_info_entry * entry)
768{
769	struct snd_info_entry *p, *n;
770
771	if (!entry)
772		return;
773	if (entry->p) {
774		mutex_lock(&info_mutex);
775		snd_info_disconnect(entry);
776		mutex_unlock(&info_mutex);
777	}
778
779	/* free all children at first */
780	list_for_each_entry_safe(p, n, &entry->children, list)
781		snd_info_free_entry(p);
782
783	p = entry->parent;
784	if (p) {
785		mutex_lock(&p->access);
786		list_del(&entry->list);
787		mutex_unlock(&p->access);
788	}
789	kfree(entry->name);
790	if (entry->private_free)
791		entry->private_free(entry);
792	kfree(entry);
793}
794EXPORT_SYMBOL(snd_info_free_entry);
795
796static int __snd_info_register(struct snd_info_entry *entry)
797{
798	struct proc_dir_entry *root, *p = NULL;
799
800	if (snd_BUG_ON(!entry))
801		return -ENXIO;
802	root = entry->parent == NULL ? snd_proc_root->p : entry->parent->p;
803	mutex_lock(&info_mutex);
804	if (entry->p || !root)
805		goto unlock;
806	if (S_ISDIR(entry->mode)) {
807		p = proc_mkdir_mode(entry->name, entry->mode, root);
808		if (!p) {
809			mutex_unlock(&info_mutex);
810			return -ENOMEM;
811		}
812	} else {
813		const struct file_operations *ops;
814		if (entry->content == SNDRV_INFO_CONTENT_DATA)
815			ops = &snd_info_entry_operations;
816		else
817			ops = &snd_info_text_entry_ops;
818		p = proc_create_data(entry->name, entry->mode, root,
819				     ops, entry);
820		if (!p) {
821			mutex_unlock(&info_mutex);
822			return -ENOMEM;
823		}
824		proc_set_size(p, entry->size);
825	}
826	entry->p = p;
827 unlock:
828	mutex_unlock(&info_mutex);
829	return 0;
830}
831
832/**
833 * snd_info_register - register the info entry
834 * @entry: the info entry
835 *
836 * Registers the proc info entry.
837 * The all children entries are registered recursively.
838 *
839 * Return: Zero if successful, or a negative error code on failure.
840 */
841int snd_info_register(struct snd_info_entry *entry)
842{
843	struct snd_info_entry *p;
844	int err;
845
846	if (!entry->p) {
847		err = __snd_info_register(entry);
848		if (err < 0)
849			return err;
850	}
851
852	list_for_each_entry(p, &entry->children, list) {
853		err = snd_info_register(p);
854		if (err < 0)
855			return err;
856	}
857
858	return 0;
859}
860EXPORT_SYMBOL(snd_info_register);
861
862/**
863 * snd_card_rw_proc_new - Create a read/write text proc file entry for the card
864 * @card: the card instance
865 * @name: the file name
866 * @private_data: the arbitrary private data
867 * @read: the read callback
868 * @write: the write callback, NULL for read-only
869 *
870 * This proc file entry will be registered via snd_card_register() call, and
871 * it will be removed automatically at the card removal, too.
872 */
873int snd_card_rw_proc_new(struct snd_card *card, const char *name,
874			 void *private_data,
875			 void (*read)(struct snd_info_entry *,
876				      struct snd_info_buffer *),
877			 void (*write)(struct snd_info_entry *entry,
878				       struct snd_info_buffer *buffer))
879{
880	struct snd_info_entry *entry;
881
882	entry = snd_info_create_card_entry(card, name, card->proc_root);
883	if (!entry)
884		return -ENOMEM;
885	snd_info_set_text_ops(entry, private_data, read);
886	if (write) {
887		entry->mode |= 0200;
888		entry->c.text.write = write;
889	}
890	return 0;
891}
892EXPORT_SYMBOL_GPL(snd_card_rw_proc_new);
893
894/*
895
896 */
897
898static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
899{
900	snd_iprintf(buffer,
901		    "Advanced Linux Sound Architecture Driver Version k%s.\n",
902		    init_utsname()->release);
903}
904
905static int __init snd_info_version_init(void)
906{
907	struct snd_info_entry *entry;
908
909	entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
910	if (entry == NULL)
911		return -ENOMEM;
912	entry->c.text.read = snd_info_version_read;
913	return snd_info_register(entry); /* freed in error path */
914}