sound/core/info.c

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