xref: /linux/sound/core/info.c (revision 71dfa617ea9f18e4585fe78364217cd32b1fc382) 
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 
20 int snd_info_check_reserved_words(const char *str)
21 {
22 	static const char * const reserved[] =
23 	{
24 		"version",
25 		"meminfo",
26 		"memdebug",
27 		"detect",
28 		"devices",
29 		"oss",
30 		"cards",
31 		"timers",
32 		"synth",
33 		"pcm",
34 		"seq",
35 		NULL
36 	};
37 	const char * const *xstr = reserved;
38 
39 	while (*xstr) {
40 		if (!strcmp(*xstr, str))
41 			return 0;
42 		xstr++;
43 	}
44 	if (!strncmp(str, "card", 4))
45 		return 0;
46 	return 1;
47 }
48 
49 static DEFINE_MUTEX(info_mutex);
50 
51 struct snd_info_private_data {
52 	struct snd_info_buffer *rbuffer;
53 	struct snd_info_buffer *wbuffer;
54 	struct snd_info_entry *entry;
55 	void *file_private_data;
56 };
57 
58 static int snd_info_version_init(void);
59 static void snd_info_clear_entries(struct snd_info_entry *entry);
60 
61 /*
62 
63  */
64 
65 static struct snd_info_entry *snd_proc_root;
66 struct snd_info_entry *snd_seq_root;
67 EXPORT_SYMBOL(snd_seq_root);
68 
69 #ifdef CONFIG_SND_OSSEMUL
70 struct snd_info_entry *snd_oss_root;
71 #endif
72 
73 static int alloc_info_private(struct snd_info_entry *entry,
74 			      struct snd_info_private_data **ret)
75 {
76 	struct snd_info_private_data *data;
77 
78 	if (!entry || !entry->p)
79 		return -ENODEV;
80 	if (!try_module_get(entry->module))
81 		return -EFAULT;
82 	data = kzalloc(sizeof(*data), GFP_KERNEL);
83 	if (!data) {
84 		module_put(entry->module);
85 		return -ENOMEM;
86 	}
87 	data->entry = entry;
88 	*ret = data;
89 	return 0;
90 }
91 
92 static bool valid_pos(loff_t pos, size_t count)
93 {
94 	if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
95 		return false;
96 	if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
97 		return false;
98 	return true;
99 }
100 
101 /*
102  * file ops for binary proc files
103  */
104 static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
105 {
106 	struct snd_info_private_data *data;
107 	struct snd_info_entry *entry;
108 	loff_t size;
109 
110 	data = file->private_data;
111 	entry = data->entry;
112 	guard(mutex)(&entry->access);
113 	if (entry->c.ops->llseek)
114 		return entry->c.ops->llseek(entry,
115 					    data->file_private_data,
116 					    file, offset, orig);
117 
118 	size = entry->size;
119 	switch (orig) {
120 	case SEEK_SET:
121 		break;
122 	case SEEK_CUR:
123 		offset += file->f_pos;
124 		break;
125 	case SEEK_END:
126 		if (!size)
127 			return -EINVAL;
128 		offset += size;
129 		break;
130 	default:
131 		return -EINVAL;
132 	}
133 	if (offset < 0)
134 		return -EINVAL;
135 	if (size && offset > size)
136 		offset = size;
137 	file->f_pos = offset;
138 	return offset;
139 }
140 
141 static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
142 				   size_t count, loff_t * offset)
143 {
144 	struct snd_info_private_data *data = file->private_data;
145 	struct snd_info_entry *entry = data->entry;
146 	size_t size;
147 	loff_t pos;
148 
149 	pos = *offset;
150 	if (!valid_pos(pos, count))
151 		return -EIO;
152 	if (pos >= entry->size)
153 		return 0;
154 	size = entry->size - pos;
155 	size = min(count, size);
156 	size = entry->c.ops->read(entry, data->file_private_data,
157 				  file, buffer, size, pos);
158 	if ((ssize_t) size > 0)
159 		*offset = pos + size;
160 	return size;
161 }
162 
163 static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
164 				    size_t count, loff_t * offset)
165 {
166 	struct snd_info_private_data *data = file->private_data;
167 	struct snd_info_entry *entry = data->entry;
168 	ssize_t size = 0;
169 	loff_t pos;
170 
171 	pos = *offset;
172 	if (!valid_pos(pos, count))
173 		return -EIO;
174 	if (count > 0) {
175 		size_t maxsize = entry->size - pos;
176 		count = min(count, maxsize);
177 		size = entry->c.ops->write(entry, data->file_private_data,
178 					   file, buffer, count, pos);
179 	}
180 	if (size > 0)
181 		*offset = pos + size;
182 	return size;
183 }
184 
185 static __poll_t snd_info_entry_poll(struct file *file, poll_table *wait)
186 {
187 	struct snd_info_private_data *data = file->private_data;
188 	struct snd_info_entry *entry = data->entry;
189 	__poll_t mask = 0;
190 
191 	if (entry->c.ops->poll)
192 		return entry->c.ops->poll(entry,
193 					  data->file_private_data,
194 					  file, wait);
195 	if (entry->c.ops->read)
196 		mask |= EPOLLIN | EPOLLRDNORM;
197 	if (entry->c.ops->write)
198 		mask |= EPOLLOUT | EPOLLWRNORM;
199 	return mask;
200 }
201 
202 static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
203 				unsigned long arg)
204 {
205 	struct snd_info_private_data *data = file->private_data;
206 	struct snd_info_entry *entry = data->entry;
207 
208 	if (!entry->c.ops->ioctl)
209 		return -ENOTTY;
210 	return entry->c.ops->ioctl(entry, data->file_private_data,
211 				   file, cmd, arg);
212 }
213 
214 static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
215 {
216 	struct inode *inode = file_inode(file);
217 	struct snd_info_private_data *data;
218 	struct snd_info_entry *entry;
219 
220 	data = file->private_data;
221 	if (data == NULL)
222 		return 0;
223 	entry = data->entry;
224 	if (!entry->c.ops->mmap)
225 		return -ENXIO;
226 	return entry->c.ops->mmap(entry, data->file_private_data,
227 				  inode, file, vma);
228 }
229 
230 static int snd_info_entry_open(struct inode *inode, struct file *file)
231 {
232 	struct snd_info_entry *entry = pde_data(inode);
233 	struct snd_info_private_data *data;
234 	int mode, err;
235 
236 	guard(mutex)(&info_mutex);
237 	err = alloc_info_private(entry, &data);
238 	if (err < 0)
239 		return err;
240 
241 	mode = file->f_flags & O_ACCMODE;
242 	if (((mode == O_RDONLY || mode == O_RDWR) && !entry->c.ops->read) ||
243 	    ((mode == O_WRONLY || mode == O_RDWR) && !entry->c.ops->write)) {
244 		err = -ENODEV;
245 		goto error;
246 	}
247 
248 	if (entry->c.ops->open) {
249 		err = entry->c.ops->open(entry, mode, &data->file_private_data);
250 		if (err < 0)
251 			goto error;
252 	}
253 
254 	file->private_data = data;
255 	return 0;
256 
257  error:
258 	kfree(data);
259 	module_put(entry->module);
260 	return err;
261 }
262 
263 static int snd_info_entry_release(struct inode *inode, struct file *file)
264 {
265 	struct snd_info_private_data *data = file->private_data;
266 	struct snd_info_entry *entry = data->entry;
267 
268 	if (entry->c.ops->release)
269 		entry->c.ops->release(entry, file->f_flags & O_ACCMODE,
270 				      data->file_private_data);
271 	module_put(entry->module);
272 	kfree(data);
273 	return 0;
274 }
275 
276 static const struct proc_ops snd_info_entry_operations =
277 {
278 	.proc_lseek	= snd_info_entry_llseek,
279 	.proc_read	= snd_info_entry_read,
280 	.proc_write	= snd_info_entry_write,
281 	.proc_poll	= snd_info_entry_poll,
282 	.proc_ioctl	= snd_info_entry_ioctl,
283 	.proc_mmap	= snd_info_entry_mmap,
284 	.proc_open	= snd_info_entry_open,
285 	.proc_release	= snd_info_entry_release,
286 };
287 
288 /*
289  * file ops for text proc files
290  */
291 static ssize_t snd_info_text_entry_write(struct file *file,
292 					 const char __user *buffer,
293 					 size_t count, loff_t *offset)
294 {
295 	struct seq_file *m = file->private_data;
296 	struct snd_info_private_data *data = m->private;
297 	struct snd_info_entry *entry = data->entry;
298 	struct snd_info_buffer *buf;
299 	loff_t pos;
300 	size_t next;
301 
302 	if (!entry->c.text.write)
303 		return -EIO;
304 	pos = *offset;
305 	if (!valid_pos(pos, count))
306 		return -EIO;
307 	next = pos + count;
308 	/* don't handle too large text inputs */
309 	if (next > 16 * 1024)
310 		return -EIO;
311 	guard(mutex)(&entry->access);
312 	buf = data->wbuffer;
313 	if (!buf) {
314 		data->wbuffer = buf = kzalloc(sizeof(*buf), GFP_KERNEL);
315 		if (!buf)
316 			return -ENOMEM;
317 	}
318 	if (next > buf->len) {
319 		char *nbuf = kvzalloc(PAGE_ALIGN(next), GFP_KERNEL);
320 		if (!nbuf)
321 			return -ENOMEM;
322 		kvfree(buf->buffer);
323 		buf->buffer = nbuf;
324 		buf->len = PAGE_ALIGN(next);
325 	}
326 	if (copy_from_user(buf->buffer + pos, buffer, count))
327 		return -EFAULT;
328 	buf->size = next;
329 	*offset = next;
330 	return count;
331 }
332 
333 static int snd_info_seq_show(struct seq_file *seq, void *p)
334 {
335 	struct snd_info_private_data *data = seq->private;
336 	struct snd_info_entry *entry = data->entry;
337 
338 	if (!entry->c.text.read) {
339 		return -EIO;
340 	} else {
341 		data->rbuffer->buffer = (char *)seq; /* XXX hack! */
342 		entry->c.text.read(entry, data->rbuffer);
343 	}
344 	return 0;
345 }
346 
347 static int snd_info_text_entry_open(struct inode *inode, struct file *file)
348 {
349 	struct snd_info_entry *entry = pde_data(inode);
350 	struct snd_info_private_data *data;
351 	int err;
352 
353 	guard(mutex)(&info_mutex);
354 	err = alloc_info_private(entry, &data);
355 	if (err < 0)
356 		return err;
357 
358 	data->rbuffer = kzalloc(sizeof(*data->rbuffer), GFP_KERNEL);
359 	if (!data->rbuffer) {
360 		err = -ENOMEM;
361 		goto error;
362 	}
363 	if (entry->size)
364 		err = single_open_size(file, snd_info_seq_show, data,
365 				       entry->size);
366 	else
367 		err = single_open(file, snd_info_seq_show, data);
368 	if (err < 0)
369 		goto error;
370 	return 0;
371 
372  error:
373 	kfree(data->rbuffer);
374 	kfree(data);
375 	module_put(entry->module);
376 	return err;
377 }
378 
379 static int snd_info_text_entry_release(struct inode *inode, struct file *file)
380 {
381 	struct seq_file *m = file->private_data;
382 	struct snd_info_private_data *data = m->private;
383 	struct snd_info_entry *entry = data->entry;
384 
385 	if (data->wbuffer && entry->c.text.write)
386 		entry->c.text.write(entry, data->wbuffer);
387 
388 	single_release(inode, file);
389 	kfree(data->rbuffer);
390 	if (data->wbuffer) {
391 		kvfree(data->wbuffer->buffer);
392 		kfree(data->wbuffer);
393 	}
394 
395 	module_put(entry->module);
396 	kfree(data);
397 	return 0;
398 }
399 
400 static const struct proc_ops snd_info_text_entry_ops =
401 {
402 	.proc_open	= snd_info_text_entry_open,
403 	.proc_release	= snd_info_text_entry_release,
404 	.proc_write	= snd_info_text_entry_write,
405 	.proc_lseek	= seq_lseek,
406 	.proc_read	= seq_read,
407 };
408 
409 static struct snd_info_entry *create_subdir(struct module *mod,
410 					    const char *name)
411 {
412 	struct snd_info_entry *entry;
413 
414 	entry = snd_info_create_module_entry(mod, name, NULL);
415 	if (!entry)
416 		return NULL;
417 	entry->mode = S_IFDIR | 0555;
418 	if (snd_info_register(entry) < 0) {
419 		snd_info_free_entry(entry);
420 		return NULL;
421 	}
422 	return entry;
423 }
424 
425 static struct snd_info_entry *
426 snd_info_create_entry(const char *name, struct snd_info_entry *parent,
427 		      struct module *module);
428 
429 int __init snd_info_init(void)
430 {
431 	snd_proc_root = snd_info_create_entry("asound", NULL, THIS_MODULE);
432 	if (!snd_proc_root)
433 		return -ENOMEM;
434 	snd_proc_root->mode = S_IFDIR | 0555;
435 	snd_proc_root->p = proc_mkdir("asound", NULL);
436 	if (!snd_proc_root->p)
437 		goto error;
438 #ifdef CONFIG_SND_OSSEMUL
439 	snd_oss_root = create_subdir(THIS_MODULE, "oss");
440 	if (!snd_oss_root)
441 		goto error;
442 #endif
443 #if IS_ENABLED(CONFIG_SND_SEQUENCER)
444 	snd_seq_root = create_subdir(THIS_MODULE, "seq");
445 	if (!snd_seq_root)
446 		goto error;
447 #endif
448 	if (snd_info_version_init() < 0 ||
449 	    snd_minor_info_init() < 0 ||
450 	    snd_minor_info_oss_init() < 0 ||
451 	    snd_card_info_init() < 0 ||
452 	    snd_info_minor_register() < 0)
453 		goto error;
454 	return 0;
455 
456  error:
457 	snd_info_free_entry(snd_proc_root);
458 	return -ENOMEM;
459 }
460 
461 int __exit snd_info_done(void)
462 {
463 	snd_info_free_entry(snd_proc_root);
464 	return 0;
465 }
466 
467 static void snd_card_id_read(struct snd_info_entry *entry,
468 			     struct snd_info_buffer *buffer)
469 {
470 	struct snd_card *card = entry->private_data;
471 
472 	snd_iprintf(buffer, "%s\n", card->id);
473 }
474 
475 /*
476  * create a card proc file
477  * called from init.c
478  */
479 int snd_info_card_create(struct snd_card *card)
480 {
481 	char str[8];
482 	struct snd_info_entry *entry;
483 
484 	if (snd_BUG_ON(!card))
485 		return -ENXIO;
486 
487 	sprintf(str, "card%i", card->number);
488 	entry = create_subdir(card->module, str);
489 	if (!entry)
490 		return -ENOMEM;
491 	card->proc_root = entry;
492 
493 	return snd_card_ro_proc_new(card, "id", card, snd_card_id_read);
494 }
495 
496 /*
497  * register the card proc file
498  * called from init.c
499  * can be called multiple times for reinitialization
500  */
501 int snd_info_card_register(struct snd_card *card)
502 {
503 	struct proc_dir_entry *p;
504 	int err;
505 
506 	if (snd_BUG_ON(!card))
507 		return -ENXIO;
508 
509 	err = snd_info_register(card->proc_root);
510 	if (err < 0)
511 		return err;
512 
513 	if (!strcmp(card->id, card->proc_root->name))
514 		return 0;
515 
516 	if (card->proc_root_link)
517 		return 0;
518 	p = proc_symlink(card->id, snd_proc_root->p, card->proc_root->name);
519 	if (!p)
520 		return -ENOMEM;
521 	card->proc_root_link = p;
522 	return 0;
523 }
524 
525 /*
526  * called on card->id change
527  */
528 void snd_info_card_id_change(struct snd_card *card)
529 {
530 	guard(mutex)(&info_mutex);
531 	if (card->proc_root_link) {
532 		proc_remove(card->proc_root_link);
533 		card->proc_root_link = NULL;
534 	}
535 	if (strcmp(card->id, card->proc_root->name))
536 		card->proc_root_link = proc_symlink(card->id,
537 						    snd_proc_root->p,
538 						    card->proc_root->name);
539 }
540 
541 /*
542  * de-register the card proc file
543  * called from init.c
544  */
545 void snd_info_card_disconnect(struct snd_card *card)
546 {
547 	if (!card)
548 		return;
549 
550 	proc_remove(card->proc_root_link);
551 	if (card->proc_root)
552 		proc_remove(card->proc_root->p);
553 
554 	guard(mutex)(&info_mutex);
555 	if (card->proc_root)
556 		snd_info_clear_entries(card->proc_root);
557 	card->proc_root_link = NULL;
558 	card->proc_root = NULL;
559 }
560 
561 /*
562  * release the card proc file resources
563  * called from init.c
564  */
565 int snd_info_card_free(struct snd_card *card)
566 {
567 	if (!card)
568 		return 0;
569 	snd_info_free_entry(card->proc_root);
570 	card->proc_root = NULL;
571 	return 0;
572 }
573 
574 
575 /**
576  * snd_info_get_line - read one line from the procfs buffer
577  * @buffer: the procfs buffer
578  * @line: the buffer to store
579  * @len: the max. buffer size
580  *
581  * Reads one line from the buffer and stores the string.
582  *
583  * Return: Zero if successful, or 1 if error or EOF.
584  */
585 int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
586 {
587 	int c;
588 
589 	if (snd_BUG_ON(!buffer))
590 		return 1;
591 	if (!buffer->buffer)
592 		return 1;
593 	if (len <= 0 || buffer->stop || buffer->error)
594 		return 1;
595 	while (!buffer->stop) {
596 		c = buffer->buffer[buffer->curr++];
597 		if (buffer->curr >= buffer->size)
598 			buffer->stop = 1;
599 		if (c == '\n')
600 			break;
601 		if (len > 1) {
602 			len--;
603 			*line++ = c;
604 		}
605 	}
606 	*line = '\0';
607 	return 0;
608 }
609 EXPORT_SYMBOL(snd_info_get_line);
610 
611 /**
612  * snd_info_get_str - parse a string token
613  * @dest: the buffer to store the string token
614  * @src: the original string
615  * @len: the max. length of token - 1
616  *
617  * Parses the original string and copy a token to the given
618  * string buffer.
619  *
620  * Return: The updated pointer of the original string so that
621  * it can be used for the next call.
622  */
623 const char *snd_info_get_str(char *dest, const char *src, int len)
624 {
625 	int c;
626 
627 	while (*src == ' ' || *src == '\t')
628 		src++;
629 	if (*src == '"' || *src == '\'') {
630 		c = *src++;
631 		while (--len > 0 && *src && *src != c) {
632 			*dest++ = *src++;
633 		}
634 		if (*src == c)
635 			src++;
636 	} else {
637 		while (--len > 0 && *src && *src != ' ' && *src != '\t') {
638 			*dest++ = *src++;
639 		}
640 	}
641 	*dest = 0;
642 	while (*src == ' ' || *src == '\t')
643 		src++;
644 	return src;
645 }
646 EXPORT_SYMBOL(snd_info_get_str);
647 
648 /*
649  * snd_info_create_entry - create an info entry
650  * @name: the proc file name
651  * @parent: the parent directory
652  *
653  * Creates an info entry with the given file name and initializes as
654  * the default state.
655  *
656  * Usually called from other functions such as
657  * snd_info_create_card_entry().
658  *
659  * Return: The pointer of the new instance, or %NULL on failure.
660  */
661 static struct snd_info_entry *
662 snd_info_create_entry(const char *name, struct snd_info_entry *parent,
663 		      struct module *module)
664 {
665 	struct snd_info_entry *entry;
666 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
667 	if (entry == NULL)
668 		return NULL;
669 	entry->name = kstrdup(name, GFP_KERNEL);
670 	if (entry->name == NULL) {
671 		kfree(entry);
672 		return NULL;
673 	}
674 	entry->mode = S_IFREG | 0444;
675 	entry->content = SNDRV_INFO_CONTENT_TEXT;
676 	mutex_init(&entry->access);
677 	INIT_LIST_HEAD(&entry->children);
678 	INIT_LIST_HEAD(&entry->list);
679 	entry->parent = parent;
680 	entry->module = module;
681 	if (parent) {
682 		guard(mutex)(&parent->access);
683 		list_add_tail(&entry->list, &parent->children);
684 	}
685 	return entry;
686 }
687 
688 /**
689  * snd_info_create_module_entry - create an info entry for the given module
690  * @module: the module pointer
691  * @name: the file name
692  * @parent: the parent directory
693  *
694  * Creates a new info entry and assigns it to the given module.
695  *
696  * Return: The pointer of the new instance, or %NULL on failure.
697  */
698 struct snd_info_entry *snd_info_create_module_entry(struct module * module,
699 					       const char *name,
700 					       struct snd_info_entry *parent)
701 {
702 	if (!parent)
703 		parent = snd_proc_root;
704 	return snd_info_create_entry(name, parent, module);
705 }
706 EXPORT_SYMBOL(snd_info_create_module_entry);
707 
708 /**
709  * snd_info_create_card_entry - create an info entry for the given card
710  * @card: the card instance
711  * @name: the file name
712  * @parent: the parent directory
713  *
714  * Creates a new info entry and assigns it to the given card.
715  *
716  * Return: The pointer of the new instance, or %NULL on failure.
717  */
718 struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
719 					     const char *name,
720 					     struct snd_info_entry * parent)
721 {
722 	if (!parent)
723 		parent = card->proc_root;
724 	return snd_info_create_entry(name, parent, card->module);
725 }
726 EXPORT_SYMBOL(snd_info_create_card_entry);
727 
728 static void snd_info_clear_entries(struct snd_info_entry *entry)
729 {
730 	struct snd_info_entry *p;
731 
732 	if (!entry->p)
733 		return;
734 	list_for_each_entry(p, &entry->children, list)
735 		snd_info_clear_entries(p);
736 	entry->p = NULL;
737 }
738 
739 /**
740  * snd_info_free_entry - release the info entry
741  * @entry: the info entry
742  *
743  * Releases the info entry.
744  */
745 void snd_info_free_entry(struct snd_info_entry * entry)
746 {
747 	struct snd_info_entry *p, *n;
748 
749 	if (!entry)
750 		return;
751 	if (entry->p) {
752 		proc_remove(entry->p);
753 		guard(mutex)(&info_mutex);
754 		snd_info_clear_entries(entry);
755 	}
756 
757 	/* free all children at first */
758 	list_for_each_entry_safe(p, n, &entry->children, list)
759 		snd_info_free_entry(p);
760 
761 	p = entry->parent;
762 	if (p) {
763 		guard(mutex)(&p->access);
764 		list_del(&entry->list);
765 	}
766 	kfree(entry->name);
767 	if (entry->private_free)
768 		entry->private_free(entry);
769 	kfree(entry);
770 }
771 EXPORT_SYMBOL(snd_info_free_entry);
772 
773 static int __snd_info_register(struct snd_info_entry *entry)
774 {
775 	struct proc_dir_entry *root, *p = NULL;
776 
777 	if (snd_BUG_ON(!entry))
778 		return -ENXIO;
779 	root = entry->parent == NULL ? snd_proc_root->p : entry->parent->p;
780 	guard(mutex)(&info_mutex);
781 	if (entry->p || !root)
782 		return 0;
783 	if (S_ISDIR(entry->mode)) {
784 		p = proc_mkdir_mode(entry->name, entry->mode, root);
785 		if (!p)
786 			return -ENOMEM;
787 	} else {
788 		const struct proc_ops *ops;
789 		if (entry->content == SNDRV_INFO_CONTENT_DATA)
790 			ops = &snd_info_entry_operations;
791 		else
792 			ops = &snd_info_text_entry_ops;
793 		p = proc_create_data(entry->name, entry->mode, root,
794 				     ops, entry);
795 		if (!p)
796 			return -ENOMEM;
797 		proc_set_size(p, entry->size);
798 	}
799 	entry->p = p;
800 	return 0;
801 }
802 
803 /**
804  * snd_info_register - register the info entry
805  * @entry: the info entry
806  *
807  * Registers the proc info entry.
808  * The all children entries are registered recursively.
809  *
810  * Return: Zero if successful, or a negative error code on failure.
811  */
812 int snd_info_register(struct snd_info_entry *entry)
813 {
814 	struct snd_info_entry *p;
815 	int err;
816 
817 	if (!entry->p) {
818 		err = __snd_info_register(entry);
819 		if (err < 0)
820 			return err;
821 	}
822 
823 	list_for_each_entry(p, &entry->children, list) {
824 		err = snd_info_register(p);
825 		if (err < 0)
826 			return err;
827 	}
828 
829 	return 0;
830 }
831 EXPORT_SYMBOL(snd_info_register);
832 
833 /**
834  * snd_card_rw_proc_new - Create a read/write text proc file entry for the card
835  * @card: the card instance
836  * @name: the file name
837  * @private_data: the arbitrary private data
838  * @read: the read callback
839  * @write: the write callback, NULL for read-only
840  *
841  * This proc file entry will be registered via snd_card_register() call, and
842  * it will be removed automatically at the card removal, too.
843  *
844  * Return: zero if successful, or a negative error code
845  */
846 int snd_card_rw_proc_new(struct snd_card *card, const char *name,
847 			 void *private_data,
848 			 void (*read)(struct snd_info_entry *,
849 				      struct snd_info_buffer *),
850 			 void (*write)(struct snd_info_entry *entry,
851 				       struct snd_info_buffer *buffer))
852 {
853 	struct snd_info_entry *entry;
854 
855 	entry = snd_info_create_card_entry(card, name, card->proc_root);
856 	if (!entry)
857 		return -ENOMEM;
858 	snd_info_set_text_ops(entry, private_data, read);
859 	if (write) {
860 		entry->mode |= 0200;
861 		entry->c.text.write = write;
862 	}
863 	return 0;
864 }
865 EXPORT_SYMBOL_GPL(snd_card_rw_proc_new);
866 
867 /*
868 
869  */
870 
871 static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
872 {
873 	snd_iprintf(buffer,
874 		    "Advanced Linux Sound Architecture Driver Version k%s.\n",
875 		    init_utsname()->release);
876 }
877 
878 static int __init snd_info_version_init(void)
879 {
880 	struct snd_info_entry *entry;
881 
882 	entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
883 	if (entry == NULL)
884 		return -ENOMEM;
885 	entry->c.text.read = snd_info_version_read;
886 	return snd_info_register(entry); /* freed in error path */
887 }
888