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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 /*
 37  *
 38  */
 39 
 40 #ifdef CONFIG_PROC_FS
 41 
 42 int snd_info_check_reserved_words(const char *str)
 43 {
 44         static char *reserved[] =
 45         {
 46                 "version",
 47                 "meminfo",
 48                 "memdebug",
 49                 "detect",
 50                 "devices",
 51                 "oss",
 52                 "cards",
 53                 "timers",
 54                 "synth",
 55                 "pcm",
 56                 "seq",
 57                 NULL
 58         };
 59         char **xstr = reserved;
 60 
 61         while (*xstr) {
 62                 if (!strcmp(*xstr, str))
 63                         return 0;
 64                 xstr++;
 65         }
 66         if (!strncmp(str, "card", 4))
 67                 return 0;
 68         return 1;
 69 }
 70 
 71 static DEFINE_MUTEX(info_mutex);
 72 
 73 struct snd_info_private_data {
 74         struct snd_info_buffer *rbuffer;
 75         struct snd_info_buffer *wbuffer;
 76         struct snd_info_entry *entry;
 77         void *file_private_data;
 78 };
 79 
 80 static int snd_info_version_init(void);
 81 static int snd_info_version_done(void);
 82 static void snd_info_disconnect(struct snd_info_entry *entry);
 83 
 84 
 85 /* resize the proc r/w buffer */
 86 static int resize_info_buffer(struct snd_info_buffer *buffer,
 87                               unsigned int nsize)
 88 {
 89         char *nbuf;
 90 
 91         nsize = PAGE_ALIGN(nsize);
 92         nbuf = krealloc(buffer->buffer, nsize, GFP_KERNEL | __GFP_ZERO);
 93         if (! nbuf)
 94                 return -ENOMEM;
 95 
 96         buffer->buffer = nbuf;
 97         buffer->len = nsize;
 98         return 0;
 99 }
100 
101 /**
102  * snd_iprintf - printf on the procfs buffer
103  * @buffer: the procfs buffer
104  * @fmt: the printf format
105  *
106  * Outputs the string on the procfs buffer just like printf().
107  *
108  * Return: The size of output string, or a negative error code.
109  */
110 int snd_iprintf(struct snd_info_buffer *buffer, const char *fmt, ...)
111 {
112         va_list args;
113         int len, res;
114         int err = 0;
115 
116         might_sleep();
117         if (buffer->stop || buffer->error)
118                 return 0;
119         len = buffer->len - buffer->size;
120         va_start(args, fmt);
121         for (;;) {
122                 va_list ap;
123                 va_copy(ap, args);
124                 res = vsnprintf(buffer->buffer + buffer->curr, len, fmt, ap);
125                 va_end(ap);
126                 if (res < len)
127                         break;
128                 err = resize_info_buffer(buffer, buffer->len + PAGE_SIZE);
129                 if (err < 0)
130                         break;
131                 len = buffer->len - buffer->size;
132         }
133         va_end(args);
134 
135         if (err < 0)
136                 return err;
137         buffer->curr += res;
138         buffer->size += res;
139         return res;
140 }
141 
142 EXPORT_SYMBOL(snd_iprintf);
143 
144 /*
145 
146  */
147 
148 static struct proc_dir_entry *snd_proc_root;
149 struct snd_info_entry *snd_seq_root;
150 EXPORT_SYMBOL(snd_seq_root);
151 
152 #ifdef CONFIG_SND_OSSEMUL
153 struct snd_info_entry *snd_oss_root;
154 #endif
155 
156 static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
157 {
158         struct snd_info_private_data *data;
159         struct snd_info_entry *entry;
160         loff_t ret = -EINVAL, size;
161 
162         data = file->private_data;
163         entry = data->entry;
164         mutex_lock(&entry->access);
165         if (entry->content == SNDRV_INFO_CONTENT_DATA &&
166             entry->c.ops->llseek) {
167                 offset = entry->c.ops->llseek(entry,
168                                               data->file_private_data,
169                                               file, offset, orig);
170                 goto out;
171         }
172         if (entry->content == SNDRV_INFO_CONTENT_DATA)
173                 size = entry->size;
174         else
175                 size = 0;
176         switch (orig) {
177         case SEEK_SET:
178                 break;
179         case SEEK_CUR:
180                 offset += file->f_pos;
181                 break;
182         case SEEK_END:
183                 if (!size)
184                         goto out;
185                 offset += size;
186                 break;
187         default:
188                 goto out;
189         }
190         if (offset < 0)
191                 goto out;
192         if (size && offset > size)
193                 offset = size;
194         file->f_pos = offset;
195         ret = offset;
196  out:
197         mutex_unlock(&entry->access);
198         return ret;
199 }
200 
201 static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
202                                    size_t count, loff_t * offset)
203 {
204         struct snd_info_private_data *data;
205         struct snd_info_entry *entry;
206         struct snd_info_buffer *buf;
207         size_t size = 0;
208         loff_t pos;
209 
210         data = file->private_data;
211         if (snd_BUG_ON(!data))
212                 return -ENXIO;
213         pos = *offset;
214         if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
215                 return -EIO;
216         if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
217                 return -EIO;
218         entry = data->entry;
219         switch (entry->content) {
220         case SNDRV_INFO_CONTENT_TEXT:
221                 buf = data->rbuffer;
222                 if (buf == NULL)
223                         return -EIO;
224                 if (pos >= buf->size)
225                         return 0;
226                 size = buf->size - pos;
227                 size = min(count, size);
228                 if (copy_to_user(buffer, buf->buffer + pos, size))
229                         return -EFAULT;
230                 break;
231         case SNDRV_INFO_CONTENT_DATA:
232                 if (pos >= entry->size)
233                         return 0;
234                 if (entry->c.ops->read) {
235                         size = entry->size - pos;
236                         size = min(count, size);
237                         size = entry->c.ops->read(entry,
238                                                   data->file_private_data,
239                                                   file, buffer, size, pos);
240                 }
241                 break;
242         }
243         if ((ssize_t) size > 0)
244                 *offset = pos + size;
245         return size;
246 }
247 
248 static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
249                                     size_t count, loff_t * offset)
250 {
251         struct snd_info_private_data *data;
252         struct snd_info_entry *entry;
253         struct snd_info_buffer *buf;
254         ssize_t size = 0;
255         loff_t pos;
256 
257         data = file->private_data;
258         if (snd_BUG_ON(!data))
259                 return -ENXIO;
260         entry = data->entry;
261         pos = *offset;
262         if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
263                 return -EIO;
264         if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
265                 return -EIO;
266         switch (entry->content) {
267         case SNDRV_INFO_CONTENT_TEXT:
268                 buf = data->wbuffer;
269                 if (buf == NULL)
270                         return -EIO;
271                 mutex_lock(&entry->access);
272                 if (pos + count >= buf->len) {
273                         if (resize_info_buffer(buf, pos + count)) {
274                                 mutex_unlock(&entry->access);
275                                 return -ENOMEM;
276                         }
277                 }
278                 if (copy_from_user(buf->buffer + pos, buffer, count)) {
279                         mutex_unlock(&entry->access);
280                         return -EFAULT;
281                 }
282                 buf->size = pos + count;
283                 mutex_unlock(&entry->access);
284                 size = count;
285                 break;
286         case SNDRV_INFO_CONTENT_DATA:
287                 if (entry->c.ops->write && count > 0) {
288                         size_t maxsize = entry->size - pos;
289                         count = min(count, maxsize);
290                         size = entry->c.ops->write(entry,
291                                                    data->file_private_data,
292                                                    file, buffer, count, pos);
293                 }
294                 break;
295         }
296         if ((ssize_t) size > 0)
297                 *offset = pos + size;
298         return size;
299 }
300 
301 static int snd_info_entry_open(struct inode *inode, struct file *file)
302 {
303         struct snd_info_entry *entry;
304         struct snd_info_private_data *data;
305         struct snd_info_buffer *buffer;
306         int mode, err;
307 
308         mutex_lock(&info_mutex);
309         entry = PDE_DATA(inode);
310         if (entry == NULL || ! entry->p) {
311                 mutex_unlock(&info_mutex);
312                 return -ENODEV;
313         }
314         if (!try_module_get(entry->module)) {
315                 err = -EFAULT;
316                 goto __error1;
317         }
318         mode = file->f_flags & O_ACCMODE;
319         if (mode == O_RDONLY || mode == O_RDWR) {
320                 if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
321                      entry->c.ops->read == NULL)) {
322                         err = -ENODEV;
323                         goto __error;
324                 }
325         }
326         if (mode == O_WRONLY || mode == O_RDWR) {
327                 if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
328                      entry->c.ops->write == NULL)) {
329                         err = -ENODEV;
330                         goto __error;
331                 }
332         }
333         data = kzalloc(sizeof(*data), GFP_KERNEL);
334         if (data == NULL) {
335                 err = -ENOMEM;
336                 goto __error;
337         }
338         data->entry = entry;
339         switch (entry->content) {
340         case SNDRV_INFO_CONTENT_TEXT:
341                 if (mode == O_RDONLY || mode == O_RDWR) {
342                         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
343                         if (buffer == NULL)
344                                 goto __nomem;
345                         data->rbuffer = buffer;
346                         buffer->len = PAGE_SIZE;
347                         buffer->buffer = kzalloc(buffer->len, GFP_KERNEL);
348                         if (buffer->buffer == NULL)
349                                 goto __nomem;
350                 }
351                 if (mode == O_WRONLY || mode == O_RDWR) {
352                         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
353                         if (buffer == NULL)
354                                 goto __nomem;
355                         data->wbuffer = buffer;
356                         buffer->len = PAGE_SIZE;
357                         buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
358                         if (buffer->buffer == NULL)
359                                 goto __nomem;
360                 }
361                 break;
362         case SNDRV_INFO_CONTENT_DATA:   /* data */
363                 if (entry->c.ops->open) {
364                         if ((err = entry->c.ops->open(entry, mode,
365                                                       &data->file_private_data)) < 0) {
366                                 kfree(data);
367                                 goto __error;
368                         }
369                 }
370                 break;
371         }
372         file->private_data = data;
373         mutex_unlock(&info_mutex);
374         if (entry->content == SNDRV_INFO_CONTENT_TEXT &&
375             (mode == O_RDONLY || mode == O_RDWR)) {
376                 if (entry->c.text.read) {
377                         mutex_lock(&entry->access);
378                         entry->c.text.read(entry, data->rbuffer);
379                         mutex_unlock(&entry->access);
380                 }
381         }
382         return 0;
383 
384  __nomem:
385         if (data->rbuffer) {
386                 kfree(data->rbuffer->buffer);
387                 kfree(data->rbuffer);
388         }
389         if (data->wbuffer) {
390                 kfree(data->wbuffer->buffer);
391                 kfree(data->wbuffer);
392         }
393         kfree(data);
394         err = -ENOMEM;
395       __error:
396         module_put(entry->module);
397       __error1:
398         mutex_unlock(&info_mutex);
399         return err;
400 }
401 
402 static int snd_info_entry_release(struct inode *inode, struct file *file)
403 {
404         struct snd_info_entry *entry;
405         struct snd_info_private_data *data;
406         int mode;
407 
408         mode = file->f_flags & O_ACCMODE;
409         data = file->private_data;
410         entry = data->entry;
411         switch (entry->content) {
412         case SNDRV_INFO_CONTENT_TEXT:
413                 if (data->rbuffer) {
414                         kfree(data->rbuffer->buffer);
415                         kfree(data->rbuffer);
416                 }
417                 if (data->wbuffer) {
418                         if (entry->c.text.write) {
419                                 entry->c.text.write(entry, data->wbuffer);
420                                 if (data->wbuffer->error) {
421                                         if (entry->card)
422                                                 dev_warn(entry->card->dev, "info: data write error to %s (%i)\n",
423                                                          entry->name,
424                                                          data->wbuffer->error);
425                                         else
426                                                 pr_warn("ALSA: info: data write error to %s (%i)\n",
427                                                         entry->name,
428                                                         data->wbuffer->error);
429                                 }
430                         }
431                         kfree(data->wbuffer->buffer);
432                         kfree(data->wbuffer);
433                 }
434                 break;
435         case SNDRV_INFO_CONTENT_DATA:
436                 if (entry->c.ops->release)
437                         entry->c.ops->release(entry, mode,
438                                               data->file_private_data);
439                 break;
440         }
441         module_put(entry->module);
442         kfree(data);
443         return 0;
444 }
445 
446 static unsigned int snd_info_entry_poll(struct file *file, poll_table * wait)
447 {
448         struct snd_info_private_data *data;
449         struct snd_info_entry *entry;
450         unsigned int mask;
451 
452         data = file->private_data;
453         if (data == NULL)
454                 return 0;
455         entry = data->entry;
456         mask = 0;
457         switch (entry->content) {
458         case SNDRV_INFO_CONTENT_DATA:
459                 if (entry->c.ops->poll)
460                         return entry->c.ops->poll(entry,
461                                                   data->file_private_data,
462                                                   file, wait);
463                 if (entry->c.ops->read)
464                         mask |= POLLIN | POLLRDNORM;
465                 if (entry->c.ops->write)
466                         mask |= POLLOUT | POLLWRNORM;
467                 break;
468         }
469         return mask;
470 }
471 
472 static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
473                                 unsigned long arg)
474 {
475         struct snd_info_private_data *data;
476         struct snd_info_entry *entry;
477 
478         data = file->private_data;
479         if (data == NULL)
480                 return 0;
481         entry = data->entry;
482         switch (entry->content) {
483         case SNDRV_INFO_CONTENT_DATA:
484                 if (entry->c.ops->ioctl)
485                         return entry->c.ops->ioctl(entry,
486                                                    data->file_private_data,
487                                                    file, cmd, arg);
488                 break;
489         }
490         return -ENOTTY;
491 }
492 
493 static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
494 {
495         struct inode *inode = file_inode(file);
496         struct snd_info_private_data *data;
497         struct snd_info_entry *entry;
498 
499         data = file->private_data;
500         if (data == NULL)
501                 return 0;
502         entry = data->entry;
503         switch (entry->content) {
504         case SNDRV_INFO_CONTENT_DATA:
505                 if (entry->c.ops->mmap)
506                         return entry->c.ops->mmap(entry,
507                                                   data->file_private_data,
508                                                   inode, file, vma);
509                 break;
510         }
511         return -ENXIO;
512 }
513 
514 static const struct file_operations snd_info_entry_operations =
515 {
516         .owner =                THIS_MODULE,
517         .llseek =               snd_info_entry_llseek,
518         .read =                 snd_info_entry_read,
519         .write =                snd_info_entry_write,
520         .poll =                 snd_info_entry_poll,
521         .unlocked_ioctl =       snd_info_entry_ioctl,
522         .mmap =                 snd_info_entry_mmap,
523         .open =                 snd_info_entry_open,
524         .release =              snd_info_entry_release,
525 };
526 
527 int __init snd_info_init(void)
528 {
529         struct proc_dir_entry *p;
530 
531         p = proc_mkdir("asound", NULL);
532         if (p == NULL)
533                 return -ENOMEM;
534         snd_proc_root = p;
535 #ifdef CONFIG_SND_OSSEMUL
536         {
537                 struct snd_info_entry *entry;
538                 if ((entry = snd_info_create_module_entry(THIS_MODULE, "oss", NULL)) == NULL)
539                         return -ENOMEM;
540                 entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
541                 if (snd_info_register(entry) < 0) {
542                         snd_info_free_entry(entry);
543                         return -ENOMEM;
544                 }
545                 snd_oss_root = entry;
546         }
547 #endif
548 #if IS_ENABLED(CONFIG_SND_SEQUENCER)
549         {
550                 struct snd_info_entry *entry;
551                 if ((entry = snd_info_create_module_entry(THIS_MODULE, "seq", NULL)) == NULL)
552                         return -ENOMEM;
553                 entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
554                 if (snd_info_register(entry) < 0) {
555                         snd_info_free_entry(entry);
556                         return -ENOMEM;
557                 }
558                 snd_seq_root = entry;
559         }
560 #endif
561         snd_info_version_init();
562         snd_minor_info_init();
563         snd_minor_info_oss_init();
564         snd_card_info_init();
565         return 0;
566 }
567 
568 int __exit snd_info_done(void)
569 {
570         snd_card_info_done();
571         snd_minor_info_oss_done();
572         snd_minor_info_done();
573         snd_info_version_done();
574         if (snd_proc_root) {
575 #if IS_ENABLED(CONFIG_SND_SEQUENCER)
576                 snd_info_free_entry(snd_seq_root);
577 #endif
578 #ifdef CONFIG_SND_OSSEMUL
579                 snd_info_free_entry(snd_oss_root);
580 #endif
581                 proc_remove(snd_proc_root);
582         }
583         return 0;
584 }
585 
586 /*
587 
588  */
589 
590 
591 /*
592  * create a card proc file
593  * called from init.c
594  */
595 int snd_info_card_create(struct snd_card *card)
596 {
597         char str[8];
598         struct snd_info_entry *entry;
599 
600         if (snd_BUG_ON(!card))
601                 return -ENXIO;
602 
603         sprintf(str, "card%i", card->number);
604         if ((entry = snd_info_create_module_entry(card->module, str, NULL)) == NULL)
605                 return -ENOMEM;
606         entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
607         if (snd_info_register(entry) < 0) {
608                 snd_info_free_entry(entry);
609                 return -ENOMEM;
610         }
611         card->proc_root = entry;
612         return 0;
613 }
614 
615 /*
616  * register the card proc file
617  * called from init.c
618  */
619 int snd_info_card_register(struct snd_card *card)
620 {
621         struct proc_dir_entry *p;
622 
623         if (snd_BUG_ON(!card))
624                 return -ENXIO;
625 
626         if (!strcmp(card->id, card->proc_root->name))
627                 return 0;
628 
629         p = proc_symlink(card->id, snd_proc_root, card->proc_root->name);
630         if (p == NULL)
631                 return -ENOMEM;
632         card->proc_root_link = p;
633         return 0;
634 }
635 
636 /*
637  * called on card->id change
638  */
639 void snd_info_card_id_change(struct snd_card *card)
640 {
641         mutex_lock(&info_mutex);
642         if (card->proc_root_link) {
643                 proc_remove(card->proc_root_link);
644                 card->proc_root_link = NULL;
645         }
646         if (strcmp(card->id, card->proc_root->name))
647                 card->proc_root_link = proc_symlink(card->id,
648                                                     snd_proc_root,
649                                                     card->proc_root->name);
650         mutex_unlock(&info_mutex);
651 }
652 
653 /*
654  * de-register the card proc file
655  * called from init.c
656  */
657 void snd_info_card_disconnect(struct snd_card *card)
658 {
659         if (!card)
660                 return;
661         mutex_lock(&info_mutex);
662         proc_remove(card->proc_root_link);
663         card->proc_root_link = NULL;
664         if (card->proc_root)
665                 snd_info_disconnect(card->proc_root);
666         mutex_unlock(&info_mutex);
667 }
668 
669 /*
670  * release the card proc file resources
671  * called from init.c
672  */
673 int snd_info_card_free(struct snd_card *card)
674 {
675         if (!card)
676                 return 0;
677         snd_info_free_entry(card->proc_root);
678         card->proc_root = NULL;
679         return 0;
680 }
681 
682 
683 /**
684  * snd_info_get_line - read one line from the procfs buffer
685  * @buffer: the procfs buffer
686  * @line: the buffer to store
687  * @len: the max. buffer size - 1
688  *
689  * Reads one line from the buffer and stores the string.
690  *
691  * Return: Zero if successful, or 1 if error or EOF.
692  */
693 int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
694 {
695         int c = -1;
696 
697         if (snd_BUG_ON(!buffer || !buffer->buffer))
698                 return 1;
699         if (len <= 0 || buffer->stop || buffer->error)
700                 return 1;
701         while (!buffer->stop) {
702                 c = buffer->buffer[buffer->curr++];
703                 if (buffer->curr >= buffer->size)
704                         buffer->stop = 1;
705                 if (c == '\n')
706                         break;
707                 if (len) {
708                         len--;
709                         *line++ = c;
710                 }
711         }
712         *line = '\0';
713         return 0;
714 }
715 
716 EXPORT_SYMBOL(snd_info_get_line);
717 
718 /**
719  * snd_info_get_str - parse a string token
720  * @dest: the buffer to store the string token
721  * @src: the original string
722  * @len: the max. length of token - 1
723  *
724  * Parses the original string and copy a token to the given
725  * string buffer.
726  *
727  * Return: The updated pointer of the original string so that
728  * it can be used for the next call.
729  */
730 const char *snd_info_get_str(char *dest, const char *src, int len)
731 {
732         int c;
733 
734         while (*src == ' ' || *src == '\t')
735                 src++;
736         if (*src == '"' || *src == '\'') {
737                 c = *src++;
738                 while (--len > 0 && *src && *src != c) {
739                         *dest++ = *src++;
740                 }
741                 if (*src == c)
742                         src++;
743         } else {
744                 while (--len > 0 && *src && *src != ' ' && *src != '\t') {
745                         *dest++ = *src++;
746                 }
747         }
748         *dest = 0;
749         while (*src == ' ' || *src == '\t')
750                 src++;
751         return src;
752 }
753 
754 EXPORT_SYMBOL(snd_info_get_str);
755 
756 /**
757  * snd_info_create_entry - create an info entry
758  * @name: the proc file name
759  *
760  * Creates an info entry with the given file name and initializes as
761  * the default state.
762  *
763  * Usually called from other functions such as
764  * snd_info_create_card_entry().
765  *
766  * Return: The pointer of the new instance, or %NULL on failure.
767  */
768 static struct snd_info_entry *snd_info_create_entry(const char *name)
769 {
770         struct snd_info_entry *entry;
771         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
772         if (entry == NULL)
773                 return NULL;
774         entry->name = kstrdup(name, GFP_KERNEL);
775         if (entry->name == NULL) {
776                 kfree(entry);
777                 return NULL;
778         }
779         entry->mode = S_IFREG | S_IRUGO;
780         entry->content = SNDRV_INFO_CONTENT_TEXT;
781         mutex_init(&entry->access);
782         INIT_LIST_HEAD(&entry->children);
783         INIT_LIST_HEAD(&entry->list);
784         return entry;
785 }
786 
787 /**
788  * snd_info_create_module_entry - create an info entry for the given module
789  * @module: the module pointer
790  * @name: the file name
791  * @parent: the parent directory
792  *
793  * Creates a new info entry and assigns it to the given module.
794  *
795  * Return: The pointer of the new instance, or %NULL on failure.
796  */
797 struct snd_info_entry *snd_info_create_module_entry(struct module * module,
798                                                const char *name,
799                                                struct snd_info_entry *parent)
800 {
801         struct snd_info_entry *entry = snd_info_create_entry(name);
802         if (entry) {
803                 entry->module = module;
804                 entry->parent = parent;
805         }
806         return entry;
807 }
808 
809 EXPORT_SYMBOL(snd_info_create_module_entry);
810 
811 /**
812  * snd_info_create_card_entry - create an info entry for the given card
813  * @card: the card instance
814  * @name: the file name
815  * @parent: the parent directory
816  *
817  * Creates a new info entry and assigns it to the given card.
818  *
819  * Return: The pointer of the new instance, or %NULL on failure.
820  */
821 struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
822                                              const char *name,
823                                              struct snd_info_entry * parent)
824 {
825         struct snd_info_entry *entry = snd_info_create_entry(name);
826         if (entry) {
827                 entry->module = card->module;
828                 entry->card = card;
829                 entry->parent = parent;
830         }
831         return entry;
832 }
833 
834 EXPORT_SYMBOL(snd_info_create_card_entry);
835 
836 static void snd_info_disconnect(struct snd_info_entry *entry)
837 {
838         struct list_head *p, *n;
839         struct proc_dir_entry *root;
840 
841         list_for_each_safe(p, n, &entry->children) {
842                 snd_info_disconnect(list_entry(p, struct snd_info_entry, list));
843         }
844 
845         if (! entry->p)
846                 return;
847         list_del_init(&entry->list);
848         root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
849         snd_BUG_ON(!root);
850         proc_remove(entry->p);
851         entry->p = NULL;
852 }
853 
854 static int snd_info_dev_free_entry(struct snd_device *device)
855 {
856         struct snd_info_entry *entry = device->device_data;
857         snd_info_free_entry(entry);
858         return 0;
859 }
860 
861 static int snd_info_dev_register_entry(struct snd_device *device)
862 {
863         struct snd_info_entry *entry = device->device_data;
864         return snd_info_register(entry);
865 }
866 
867 /**
868  * snd_card_proc_new - create an info entry for the given card
869  * @card: the card instance
870  * @name: the file name
871  * @entryp: the pointer to store the new info entry
872  *
873  * Creates a new info entry and assigns it to the given card.
874  * Unlike snd_info_create_card_entry(), this function registers the
875  * info entry as an ALSA device component, so that it can be
876  * unregistered/released without explicit call.
877  * Also, you don't have to register this entry via snd_info_register(),
878  * since this will be registered by snd_card_register() automatically.
879  *
880  * The parent is assumed as card->proc_root.
881  *
882  * For releasing this entry, use snd_device_free() instead of
883  * snd_info_free_entry(). 
884  *
885  * Return: Zero if successful, or a negative error code on failure.
886  */
887 int snd_card_proc_new(struct snd_card *card, const char *name,
888                       struct snd_info_entry **entryp)
889 {
890         static struct snd_device_ops ops = {
891                 .dev_free = snd_info_dev_free_entry,
892                 .dev_register = snd_info_dev_register_entry,
893                 /* disconnect is done via snd_info_card_disconnect() */
894         };
895         struct snd_info_entry *entry;
896         int err;
897 
898         entry = snd_info_create_card_entry(card, name, card->proc_root);
899         if (! entry)
900                 return -ENOMEM;
901         if ((err = snd_device_new(card, SNDRV_DEV_INFO, entry, &ops)) < 0) {
902                 snd_info_free_entry(entry);
903                 return err;
904         }
905         if (entryp)
906                 *entryp = entry;
907         return 0;
908 }
909 
910 EXPORT_SYMBOL(snd_card_proc_new);
911 
912 /**
913  * snd_info_free_entry - release the info entry
914  * @entry: the info entry
915  *
916  * Releases the info entry.  Don't call this after registered.
917  */
918 void snd_info_free_entry(struct snd_info_entry * entry)
919 {
920         if (entry == NULL)
921                 return;
922         if (entry->p) {
923                 mutex_lock(&info_mutex);
924                 snd_info_disconnect(entry);
925                 mutex_unlock(&info_mutex);
926         }
927         kfree(entry->name);
928         if (entry->private_free)
929                 entry->private_free(entry);
930         kfree(entry);
931 }
932 
933 EXPORT_SYMBOL(snd_info_free_entry);
934 
935 /**
936  * snd_info_register - register the info entry
937  * @entry: the info entry
938  *
939  * Registers the proc info entry.
940  *
941  * Return: Zero if successful, or a negative error code on failure.
942  */
943 int snd_info_register(struct snd_info_entry * entry)
944 {
945         struct proc_dir_entry *root, *p = NULL;
946 
947         if (snd_BUG_ON(!entry))
948                 return -ENXIO;
949         root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
950         mutex_lock(&info_mutex);
951         if (S_ISDIR(entry->mode)) {
952                 p = proc_mkdir_mode(entry->name, entry->mode, root);
953                 if (!p) {
954                         mutex_unlock(&info_mutex);
955                         return -ENOMEM;
956                 }
957         } else {
958                 p = proc_create_data(entry->name, entry->mode, root,
959                                         &snd_info_entry_operations, entry);
960                 if (!p) {
961                         mutex_unlock(&info_mutex);
962                         return -ENOMEM;
963                 }
964                 proc_set_size(p, entry->size);
965         }
966         entry->p = p;
967         if (entry->parent)
968                 list_add_tail(&entry->list, &entry->parent->children);
969         mutex_unlock(&info_mutex);
970         return 0;
971 }
972 
973 EXPORT_SYMBOL(snd_info_register);
974 
975 /*
976 
977  */
978 
979 static struct snd_info_entry *snd_info_version_entry;
980 
981 static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
982 {
983         snd_iprintf(buffer,
984                     "Advanced Linux Sound Architecture Driver Version k%s.\n",
985                     init_utsname()->release);
986 }
987 
988 static int __init snd_info_version_init(void)
989 {
990         struct snd_info_entry *entry;
991 
992         entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
993         if (entry == NULL)
994                 return -ENOMEM;
995         entry->c.text.read = snd_info_version_read;
996         if (snd_info_register(entry) < 0) {
997                 snd_info_free_entry(entry);
998                 return -ENOMEM;
999         }
1000         snd_info_version_entry = entry;
1001         return 0;
1002 }
1003 
1004 static int __exit snd_info_version_done(void)
1005 {
1006         snd_info_free_entry(snd_info_version_entry);
1007         return 0;
1008 }
1009 
1010 #endif /* CONFIG_PROC_FS */
1011 

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