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

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  1 /*
  2  *  Information interface for ALSA driver
  3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
  4  *
  5  *
  6  *   This program is free software; you can redistribute it and/or modify
  7  *   it under the terms of the GNU General Public License as published by
  8  *   the Free Software Foundation; either version 2 of the License, or
  9  *   (at your option) any later version.
 10  *
 11  *   This program is distributed in the hope that it will be useful,
 12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14  *   GNU General Public License for more details.
 15  *
 16  *   You should have received a copy of the GNU General Public License
 17  *   along with this program; if not, write to the Free Software
 18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 19  *
 20  */
 21 
 22 #include <linux/init.h>
 23 #include <linux/time.h>
 24 #include <linux/mm.h>
 25 #include <linux/slab.h>
 26 #include <linux/string.h>
 27 #include <linux/module.h>
 28 #include <sound/core.h>
 29 #include <sound/minors.h>
 30 #include <sound/info.h>
 31 #include <linux/utsname.h>
 32 #include <linux/proc_fs.h>
 33 #include <linux/mutex.h>
 34 #include <stdarg.h>
 35 
 36 int snd_info_check_reserved_words(const char *str)
 37 {
 38         static char *reserved[] =
 39         {
 40                 "version",
 41                 "meminfo",
 42                 "memdebug",
 43                 "detect",
 44                 "devices",
 45                 "oss",
 46                 "cards",
 47                 "timers",
 48                 "synth",
 49                 "pcm",
 50                 "seq",
 51                 NULL
 52         };
 53         char **xstr = reserved;
 54 
 55         while (*xstr) {
 56                 if (!strcmp(*xstr, str))
 57                         return 0;
 58                 xstr++;
 59         }
 60         if (!strncmp(str, "card", 4))
 61                 return 0;
 62         return 1;
 63 }
 64 
 65 static DEFINE_MUTEX(info_mutex);
 66 
 67 struct snd_info_private_data {
 68         struct snd_info_buffer *rbuffer;
 69         struct snd_info_buffer *wbuffer;
 70         struct snd_info_entry *entry;
 71         void *file_private_data;
 72 };
 73 
 74 static int snd_info_version_init(void);
 75 static void snd_info_disconnect(struct snd_info_entry *entry);
 76 
 77 /*
 78 
 79  */
 80 
 81 static struct snd_info_entry *snd_proc_root;
 82 struct snd_info_entry *snd_seq_root;
 83 EXPORT_SYMBOL(snd_seq_root);
 84 
 85 #ifdef CONFIG_SND_OSSEMUL
 86 struct snd_info_entry *snd_oss_root;
 87 #endif
 88 
 89 static int alloc_info_private(struct snd_info_entry *entry,
 90                               struct snd_info_private_data **ret)
 91 {
 92         struct snd_info_private_data *data;
 93 
 94         if (!entry || !entry->p)
 95                 return -ENODEV;
 96         if (!try_module_get(entry->module))
 97                 return -EFAULT;
 98         data = kzalloc(sizeof(*data), GFP_KERNEL);
 99         if (!data) {
100                 module_put(entry->module);
101                 return -ENOMEM;
102         }
103         data->entry = entry;
104         *ret = data;
105         return 0;
106 }
107 
108 static bool valid_pos(loff_t pos, size_t count)
109 {
110         if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
111                 return false;
112         if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
113                 return false;
114         return true;
115 }
116 
117 /*
118  * file ops for binary proc files
119  */
120 static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
121 {
122         struct snd_info_private_data *data;
123         struct snd_info_entry *entry;
124         loff_t ret = -EINVAL, size;
125 
126         data = file->private_data;
127         entry = data->entry;
128         mutex_lock(&entry->access);
129         if (entry->c.ops->llseek) {
130                 offset = entry->c.ops->llseek(entry,
131                                               data->file_private_data,
132                                               file, offset, orig);
133                 goto out;
134         }
135 
136         size = entry->size;
137         switch (orig) {
138         case SEEK_SET:
139                 break;
140         case SEEK_CUR:
141                 offset += file->f_pos;
142                 break;
143         case SEEK_END:
144                 if (!size)
145                         goto out;
146                 offset += size;
147                 break;
148         default:
149                 goto out;
150         }
151         if (offset < 0)
152                 goto out;
153         if (size && offset > size)
154                 offset = size;
155         file->f_pos = offset;
156         ret = offset;
157  out:
158         mutex_unlock(&entry->access);
159         return ret;
160 }
161 
162 static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
163                                    size_t count, loff_t * offset)
164 {
165         struct snd_info_private_data *data = file->private_data;
166         struct snd_info_entry *entry = data->entry;
167         size_t size;
168         loff_t pos;
169 
170         pos = *offset;
171         if (!valid_pos(pos, count))
172                 return -EIO;
173         if (pos >= entry->size)
174                 return 0;
175         size = entry->size - pos;
176         size = min(count, size);
177         size = entry->c.ops->read(entry, data->file_private_data,
178                                   file, buffer, size, pos);
179         if ((ssize_t) size > 0)
180                 *offset = pos + size;
181         return size;
182 }
183 
184 static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
185                                     size_t count, loff_t * offset)
186 {
187         struct snd_info_private_data *data = file->private_data;
188         struct snd_info_entry *entry = data->entry;
189         ssize_t size = 0;
190         loff_t pos;
191 
192         pos = *offset;
193         if (!valid_pos(pos, count))
194                 return -EIO;
195         if (count > 0) {
196                 size_t maxsize = entry->size - pos;
197                 count = min(count, maxsize);
198                 size = entry->c.ops->write(entry, data->file_private_data,
199                                            file, buffer, count, pos);
200         }
201         if (size > 0)
202                 *offset = pos + size;
203         return size;
204 }
205 
206 static unsigned int snd_info_entry_poll(struct file *file, poll_table *wait)
207 {
208         struct snd_info_private_data *data = file->private_data;
209         struct snd_info_entry *entry = data->entry;
210         unsigned int mask = 0;
211 
212         if (entry->c.ops->poll)
213                 return entry->c.ops->poll(entry,
214                                           data->file_private_data,
215                                           file, wait);
216         if (entry->c.ops->read)
217                 mask |= POLLIN | POLLRDNORM;
218         if (entry->c.ops->write)
219                 mask |= POLLOUT | POLLWRNORM;
220         return mask;
221 }
222 
223 static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
224                                 unsigned long arg)
225 {
226         struct snd_info_private_data *data = file->private_data;
227         struct snd_info_entry *entry = data->entry;
228 
229         if (!entry->c.ops->ioctl)
230                 return -ENOTTY;
231         return entry->c.ops->ioctl(entry, data->file_private_data,
232                                    file, cmd, arg);
233 }
234 
235 static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
236 {
237         struct inode *inode = file_inode(file);
238         struct snd_info_private_data *data;
239         struct snd_info_entry *entry;
240 
241         data = file->private_data;
242         if (data == NULL)
243                 return 0;
244         entry = data->entry;
245         if (!entry->c.ops->mmap)
246                 return -ENXIO;
247         return entry->c.ops->mmap(entry, data->file_private_data,
248                                   inode, file, vma);
249 }
250 
251 static int snd_info_entry_open(struct inode *inode, struct file *file)
252 {
253         struct snd_info_entry *entry = PDE_DATA(inode);
254         struct snd_info_private_data *data;
255         int mode, err;
256 
257         mutex_lock(&info_mutex);
258         err = alloc_info_private(entry, &data);
259         if (err < 0)
260                 goto unlock;
261 
262         mode = file->f_flags & O_ACCMODE;
263         if (((mode == O_RDONLY || mode == O_RDWR) && !entry->c.ops->read) ||
264             ((mode == O_WRONLY || mode == O_RDWR) && !entry->c.ops->write)) {
265                 err = -ENODEV;
266                 goto error;
267         }
268 
269         if (entry->c.ops->open) {
270                 err = entry->c.ops->open(entry, mode, &data->file_private_data);
271                 if (err < 0)
272                         goto error;
273         }
274 
275         file->private_data = data;
276         mutex_unlock(&info_mutex);
277         return 0;
278 
279  error:
280         kfree(data);
281         module_put(entry->module);
282  unlock:
283         mutex_unlock(&info_mutex);
284         return err;
285 }
286 
287 static int snd_info_entry_release(struct inode *inode, struct file *file)
288 {
289         struct snd_info_private_data *data = file->private_data;
290         struct snd_info_entry *entry = data->entry;
291 
292         if (entry->c.ops->release)
293                 entry->c.ops->release(entry, file->f_flags & O_ACCMODE,
294                                       data->file_private_data);
295         module_put(entry->module);
296         kfree(data);
297         return 0;
298 }
299 
300 static const struct file_operations snd_info_entry_operations =
301 {
302         .owner =                THIS_MODULE,
303         .llseek =               snd_info_entry_llseek,
304         .read =                 snd_info_entry_read,
305         .write =                snd_info_entry_write,
306         .poll =                 snd_info_entry_poll,
307         .unlocked_ioctl =       snd_info_entry_ioctl,
308         .mmap =                 snd_info_entry_mmap,
309         .open =                 snd_info_entry_open,
310         .release =              snd_info_entry_release,
311 };
312 
313 /*
314  * file ops for text proc files
315  */
316 static ssize_t snd_info_text_entry_write(struct file *file,
317                                          const char __user *buffer,
318                                          size_t count, loff_t *offset)
319 {
320         struct seq_file *m = file->private_data;
321         struct snd_info_private_data *data = m->private;
322         struct snd_info_entry *entry = data->entry;
323         struct snd_info_buffer *buf;
324         loff_t pos;
325         size_t next;
326         int err = 0;
327 
328         if (!entry->c.text.write)
329                 return -EIO;
330         pos = *offset;
331         if (!valid_pos(pos, count))
332                 return -EIO;
333         next = pos + count;
334         /* don't handle too large text inputs */
335         if (next > 16 * 1024)
336                 return -EIO;
337         mutex_lock(&entry->access);
338         buf = data->wbuffer;
339         if (!buf) {
340                 data->wbuffer = buf = kzalloc(sizeof(*buf), GFP_KERNEL);
341                 if (!buf) {
342                         err = -ENOMEM;
343                         goto error;
344                 }
345         }
346         if (next > buf->len) {
347                 char *nbuf = kvzalloc(PAGE_ALIGN(next), GFP_KERNEL);
348                 if (!nbuf) {
349                         err = -ENOMEM;
350                         goto error;
351                 }
352                 kvfree(buf->buffer);
353                 buf->buffer = nbuf;
354                 buf->len = PAGE_ALIGN(next);
355         }
356         if (copy_from_user(buf->buffer + pos, buffer, count)) {
357                 err = -EFAULT;
358                 goto error;
359         }
360         buf->size = next;
361  error:
362         mutex_unlock(&entry->access);
363         if (err < 0)
364                 return err;
365         *offset = next;
366         return count;
367 }
368 
369 static int snd_info_seq_show(struct seq_file *seq, void *p)
370 {
371         struct snd_info_private_data *data = seq->private;
372         struct snd_info_entry *entry = data->entry;
373 
374         if (!entry->c.text.read) {
375                 return -EIO;
376         } else {
377                 data->rbuffer->buffer = (char *)seq; /* XXX hack! */
378                 entry->c.text.read(entry, data->rbuffer);
379         }
380         return 0;
381 }
382 
383 static int snd_info_text_entry_open(struct inode *inode, struct file *file)
384 {
385         struct snd_info_entry *entry = PDE_DATA(inode);
386         struct snd_info_private_data *data;
387         int err;
388 
389         mutex_lock(&info_mutex);
390         err = alloc_info_private(entry, &data);
391         if (err < 0)
392                 goto unlock;
393 
394         data->rbuffer = kzalloc(sizeof(*data->rbuffer), GFP_KERNEL);
395         if (!data->rbuffer) {
396                 err = -ENOMEM;
397                 goto error;
398         }
399         if (entry->size)
400                 err = single_open_size(file, snd_info_seq_show, data,
401                                        entry->size);
402         else
403                 err = single_open(file, snd_info_seq_show, data);
404         if (err < 0)
405                 goto error;
406         mutex_unlock(&info_mutex);
407         return 0;
408 
409  error:
410         kfree(data->rbuffer);
411         kfree(data);
412         module_put(entry->module);
413  unlock:
414         mutex_unlock(&info_mutex);
415         return err;
416 }
417 
418 static int snd_info_text_entry_release(struct inode *inode, struct file *file)
419 {
420         struct seq_file *m = file->private_data;
421         struct snd_info_private_data *data = m->private;
422         struct snd_info_entry *entry = data->entry;
423 
424         if (data->wbuffer && entry->c.text.write)
425                 entry->c.text.write(entry, data->wbuffer);
426 
427         single_release(inode, file);
428         kfree(data->rbuffer);
429         if (data->wbuffer) {
430                 kvfree(data->wbuffer->buffer);
431                 kfree(data->wbuffer);
432         }
433 
434         module_put(entry->module);
435         kfree(data);
436         return 0;
437 }
438 
439 static const struct file_operations snd_info_text_entry_ops =
440 {
441         .owner =                THIS_MODULE,
442         .open =                 snd_info_text_entry_open,
443         .release =              snd_info_text_entry_release,
444         .write =                snd_info_text_entry_write,
445         .llseek =               seq_lseek,
446         .read =                 seq_read,
447 };
448 
449 static struct snd_info_entry *create_subdir(struct module *mod,
450                                             const char *name)
451 {
452         struct snd_info_entry *entry;
453 
454         entry = snd_info_create_module_entry(mod, name, NULL);
455         if (!entry)
456                 return NULL;
457         entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
458         if (snd_info_register(entry) < 0) {
459                 snd_info_free_entry(entry);
460                 return NULL;
461         }
462         return entry;
463 }
464 
465 static struct snd_info_entry *
466 snd_info_create_entry(const char *name, struct snd_info_entry *parent);
467 
468 int __init snd_info_init(void)
469 {
470         snd_proc_root = snd_info_create_entry("asound", NULL);
471         if (!snd_proc_root)
472                 return -ENOMEM;
473         snd_proc_root->mode = S_IFDIR | S_IRUGO | S_IXUGO;
474         snd_proc_root->p = proc_mkdir("asound", NULL);
475         if (!snd_proc_root->p)
476                 goto error;
477 #ifdef CONFIG_SND_OSSEMUL
478         snd_oss_root = create_subdir(THIS_MODULE, "oss");
479         if (!snd_oss_root)
480                 goto error;
481 #endif
482 #if IS_ENABLED(CONFIG_SND_SEQUENCER)
483         snd_seq_root = create_subdir(THIS_MODULE, "seq");
484         if (!snd_seq_root)
485                 goto error;
486 #endif
487         if (snd_info_version_init() < 0 ||
488             snd_minor_info_init() < 0 ||
489             snd_minor_info_oss_init() < 0 ||
490             snd_card_info_init() < 0 ||
491             snd_info_minor_register() < 0)
492                 goto error;
493         return 0;
494 
495  error:
496         snd_info_free_entry(snd_proc_root);
497         return -ENOMEM;
498 }
499 
500 int __exit snd_info_done(void)
501 {
502         snd_info_free_entry(snd_proc_root);
503         return 0;
504 }
505 
506 /*
507  * create a card proc file
508  * called from init.c
509  */
510 int snd_info_card_create(struct snd_card *card)
511 {
512         char str[8];
513         struct snd_info_entry *entry;
514 
515         if (snd_BUG_ON(!card))
516                 return -ENXIO;
517 
518         sprintf(str, "card%i", card->number);
519         entry = create_subdir(card->module, str);
520         if (!entry)
521                 return -ENOMEM;
522         card->proc_root = entry;
523         return 0;
524 }
525 
526 /* register all pending info entries */
527 static int snd_info_register_recursive(struct snd_info_entry *entry)
528 {
529         struct snd_info_entry *p;
530         int err;
531 
532         if (!entry->p) {
533                 err = snd_info_register(entry);
534                 if (err < 0)
535                         return err;
536         }
537 
538         list_for_each_entry(p, &entry->children, list) {
539                 err = snd_info_register_recursive(p);
540                 if (err < 0)
541                         return err;
542         }
543 
544         return 0;
545 }
546 
547 /*
548  * register the card proc file
549  * called from init.c
550  * can be called multiple times for reinitialization
551  */
552 int snd_info_card_register(struct snd_card *card)
553 {
554         struct proc_dir_entry *p;
555         int err;
556 
557         if (snd_BUG_ON(!card))
558                 return -ENXIO;
559 
560         err = snd_info_register_recursive(card->proc_root);
561         if (err < 0)
562                 return err;
563 
564         if (!strcmp(card->id, card->proc_root->name))
565                 return 0;
566 
567         if (card->proc_root_link)
568                 return 0;
569         p = proc_symlink(card->id, snd_proc_root->p, card->proc_root->name);
570         if (!p)
571                 return -ENOMEM;
572         card->proc_root_link = p;
573         return 0;
574 }
575 
576 /*
577  * called on card->id change
578  */
579 void snd_info_card_id_change(struct snd_card *card)
580 {
581         mutex_lock(&info_mutex);
582         if (card->proc_root_link) {
583                 proc_remove(card->proc_root_link);
584                 card->proc_root_link = NULL;
585         }
586         if (strcmp(card->id, card->proc_root->name))
587                 card->proc_root_link = proc_symlink(card->id,
588                                                     snd_proc_root->p,
589                                                     card->proc_root->name);
590         mutex_unlock(&info_mutex);
591 }
592 
593 /*
594  * de-register the card proc file
595  * called from init.c
596  */
597 void snd_info_card_disconnect(struct snd_card *card)
598 {
599         if (!card)
600                 return;
601         mutex_lock(&info_mutex);
602         proc_remove(card->proc_root_link);
603         card->proc_root_link = NULL;
604         if (card->proc_root)
605                 snd_info_disconnect(card->proc_root);
606         mutex_unlock(&info_mutex);
607 }
608 
609 /*
610  * release the card proc file resources
611  * called from init.c
612  */
613 int snd_info_card_free(struct snd_card *card)
614 {
615         if (!card)
616                 return 0;
617         snd_info_free_entry(card->proc_root);
618         card->proc_root = NULL;
619         return 0;
620 }
621 
622 
623 /**
624  * snd_info_get_line - read one line from the procfs buffer
625  * @buffer: the procfs buffer
626  * @line: the buffer to store
627  * @len: the max. buffer size
628  *
629  * Reads one line from the buffer and stores the string.
630  *
631  * Return: Zero if successful, or 1 if error or EOF.
632  */
633 int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
634 {
635         int c = -1;
636 
637         if (snd_BUG_ON(!buffer || !buffer->buffer))
638                 return 1;
639         if (len <= 0 || buffer->stop || buffer->error)
640                 return 1;
641         while (!buffer->stop) {
642                 c = buffer->buffer[buffer->curr++];
643                 if (buffer->curr >= buffer->size)
644                         buffer->stop = 1;
645                 if (c == '\n')
646                         break;
647                 if (len > 1) {
648                         len--;
649                         *line++ = c;
650                 }
651         }
652         *line = '\0';
653         return 0;
654 }
655 EXPORT_SYMBOL(snd_info_get_line);
656 
657 /**
658  * snd_info_get_str - parse a string token
659  * @dest: the buffer to store the string token
660  * @src: the original string
661  * @len: the max. length of token - 1
662  *
663  * Parses the original string and copy a token to the given
664  * string buffer.
665  *
666  * Return: The updated pointer of the original string so that
667  * it can be used for the next call.
668  */
669 const char *snd_info_get_str(char *dest, const char *src, int len)
670 {
671         int c;
672 
673         while (*src == ' ' || *src == '\t')
674                 src++;
675         if (*src == '"' || *src == '\'') {
676                 c = *src++;
677                 while (--len > 0 && *src && *src != c) {
678                         *dest++ = *src++;
679                 }
680                 if (*src == c)
681                         src++;
682         } else {
683                 while (--len > 0 && *src && *src != ' ' && *src != '\t') {
684                         *dest++ = *src++;
685                 }
686         }
687         *dest = 0;
688         while (*src == ' ' || *src == '\t')
689                 src++;
690         return src;
691 }
692 EXPORT_SYMBOL(snd_info_get_str);
693 
694 /*
695  * snd_info_create_entry - create an info entry
696  * @name: the proc file name
697  * @parent: the parent directory
698  *
699  * Creates an info entry with the given file name and initializes as
700  * the default state.
701  *
702  * Usually called from other functions such as
703  * snd_info_create_card_entry().
704  *
705  * Return: The pointer of the new instance, or %NULL on failure.
706  */
707 static struct snd_info_entry *
708 snd_info_create_entry(const char *name, struct snd_info_entry *parent)
709 {
710         struct snd_info_entry *entry;
711         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
712         if (entry == NULL)
713                 return NULL;
714         entry->name = kstrdup(name, GFP_KERNEL);
715         if (entry->name == NULL) {
716                 kfree(entry);
717                 return NULL;
718         }
719         entry->mode = S_IFREG | S_IRUGO;
720         entry->content = SNDRV_INFO_CONTENT_TEXT;
721         mutex_init(&entry->access);
722         INIT_LIST_HEAD(&entry->children);
723         INIT_LIST_HEAD(&entry->list);
724         entry->parent = parent;
725         if (parent)
726                 list_add_tail(&entry->list, &parent->children);
727         return entry;
728 }
729 
730 /**
731  * snd_info_create_module_entry - create an info entry for the given module
732  * @module: the module pointer
733  * @name: the file name
734  * @parent: the parent directory
735  *
736  * Creates a new info entry and assigns it to the given module.
737  *
738  * Return: The pointer of the new instance, or %NULL on failure.
739  */
740 struct snd_info_entry *snd_info_create_module_entry(struct module * module,
741                                                const char *name,
742                                                struct snd_info_entry *parent)
743 {
744         struct snd_info_entry *entry = snd_info_create_entry(name, parent);
745         if (entry)
746                 entry->module = module;
747         return entry;
748 }
749 EXPORT_SYMBOL(snd_info_create_module_entry);
750 
751 /**
752  * snd_info_create_card_entry - create an info entry for the given card
753  * @card: the card instance
754  * @name: the file name
755  * @parent: the parent directory
756  *
757  * Creates a new info entry and assigns it to the given card.
758  *
759  * Return: The pointer of the new instance, or %NULL on failure.
760  */
761 struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
762                                              const char *name,
763                                              struct snd_info_entry * parent)
764 {
765         struct snd_info_entry *entry = snd_info_create_entry(name, parent);
766         if (entry) {
767                 entry->module = card->module;
768                 entry->card = card;
769         }
770         return entry;
771 }
772 EXPORT_SYMBOL(snd_info_create_card_entry);
773 
774 static void snd_info_disconnect(struct snd_info_entry *entry)
775 {
776         struct snd_info_entry *p;
777 
778         if (!entry->p)
779                 return;
780         list_for_each_entry(p, &entry->children, list)
781                 snd_info_disconnect(p);
782         proc_remove(entry->p);
783         entry->p = NULL;
784 }
785 
786 /**
787  * snd_info_free_entry - release the info entry
788  * @entry: the info entry
789  *
790  * Releases the info entry.
791  */
792 void snd_info_free_entry(struct snd_info_entry * entry)
793 {
794         struct snd_info_entry *p, *n;
795 
796         if (!entry)
797                 return;
798         if (entry->p) {
799                 mutex_lock(&info_mutex);
800                 snd_info_disconnect(entry);
801                 mutex_unlock(&info_mutex);
802         }
803 
804         /* free all children at first */
805         list_for_each_entry_safe(p, n, &entry->children, list)
806                 snd_info_free_entry(p);
807 
808         list_del(&entry->list);
809         kfree(entry->name);
810         if (entry->private_free)
811                 entry->private_free(entry);
812         kfree(entry);
813 }
814 EXPORT_SYMBOL(snd_info_free_entry);
815 
816 /**
817  * snd_info_register - register the info entry
818  * @entry: the info entry
819  *
820  * Registers the proc info entry.
821  *
822  * Return: Zero if successful, or a negative error code on failure.
823  */
824 int snd_info_register(struct snd_info_entry * entry)
825 {
826         struct proc_dir_entry *root, *p = NULL;
827 
828         if (snd_BUG_ON(!entry))
829                 return -ENXIO;
830         root = entry->parent == NULL ? snd_proc_root->p : entry->parent->p;
831         mutex_lock(&info_mutex);
832         if (S_ISDIR(entry->mode)) {
833                 p = proc_mkdir_mode(entry->name, entry->mode, root);
834                 if (!p) {
835                         mutex_unlock(&info_mutex);
836                         return -ENOMEM;
837                 }
838         } else {
839                 const struct file_operations *ops;
840                 if (entry->content == SNDRV_INFO_CONTENT_DATA)
841                         ops = &snd_info_entry_operations;
842                 else
843                         ops = &snd_info_text_entry_ops;
844                 p = proc_create_data(entry->name, entry->mode, root,
845                                      ops, entry);
846                 if (!p) {
847                         mutex_unlock(&info_mutex);
848                         return -ENOMEM;
849                 }
850                 proc_set_size(p, entry->size);
851         }
852         entry->p = p;
853         mutex_unlock(&info_mutex);
854         return 0;
855 }
856 EXPORT_SYMBOL(snd_info_register);
857 
858 /*
859 
860  */
861 
862 static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
863 {
864         snd_iprintf(buffer,
865                     "Advanced Linux Sound Architecture Driver Version k%s.\n",
866                     init_utsname()->release);
867 }
868 
869 static int __init snd_info_version_init(void)
870 {
871         struct snd_info_entry *entry;
872 
873         entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
874         if (entry == NULL)
875                 return -ENOMEM;
876         entry->c.text.read = snd_info_version_read;
877         return snd_info_register(entry); /* freed in error path */
878 }
879 

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