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