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 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         pos = *offset;
 329         if (!valid_pos(pos, count))
 330                 return -EIO;
 331         next = pos + count;
 332         mutex_lock(&entry->access);
 333         buf = data->wbuffer;
 334         if (!buf) {
 335                 data->wbuffer = buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 336                 if (!buf) {
 337                         err = -ENOMEM;
 338                         goto error;
 339                 }
 340         }
 341         if (next > buf->len) {
 342                 char *nbuf = krealloc(buf->buffer, PAGE_ALIGN(next),
 343                                       GFP_KERNEL | __GFP_ZERO);
 344                 if (!nbuf) {
 345                         err = -ENOMEM;
 346                         goto error;
 347                 }
 348                 buf->buffer = nbuf;
 349                 buf->len = PAGE_ALIGN(next);
 350         }
 351         if (copy_from_user(buf->buffer + pos, buffer, count)) {
 352                 err = -EFAULT;
 353                 goto error;
 354         }
 355         buf->size = next;
 356  error:
 357         mutex_unlock(&entry->access);
 358         if (err < 0)
 359                 return err;
 360         *offset = next;
 361         return count;
 362 }
 363
 364 static int snd_info_seq_show(struct seq_file *seq, void *p)
 365 {
 366         struct snd_info_private_data *data = seq->private;
 367         struct snd_info_entry *entry = data->entry;
 368
 369         if (entry->c.text.read) {
 370                 data->rbuffer->buffer = (char *)seq; /* XXX hack! */
 371                 entry->c.text.read(entry, data->rbuffer);
 372         }
 373         return 0;
 374 }
 375
 376 static int snd_info_text_entry_open(struct inode *inode, struct file *file)
 377 {
 378         struct snd_info_entry *entry = PDE_DATA(inode);
 379         struct snd_info_private_data *data;
 380         int err;
 381
 382         mutex_lock(&info_mutex);
 383         err = alloc_info_private(entry, &data);
 384         if (err < 0)
 385                 goto unlock;
 386
 387         data->rbuffer = kzalloc(sizeof(*data->rbuffer), GFP_KERNEL);
 388         if (!data->rbuffer) {
 389                 err = -ENOMEM;
 390                 goto error;
 391         }
 392         if (entry->size)
 393                 err = single_open_size(file, snd_info_seq_show, data,
 394                                        entry->size);
 395         else
 396                 err = single_open(file, snd_info_seq_show, data);
 397         if (err < 0)
 398                 goto error;
 399         mutex_unlock(&info_mutex);
 400         return 0;
 401
 402  error:
 403         kfree(data->rbuffer);
 404         kfree(data);
 405         module_put(entry->module);
 406  unlock:
 407         mutex_unlock(&info_mutex);
 408         return err;
 409 }
 410
 411 static int snd_info_text_entry_release(struct inode *inode, struct file *file)
 412 {
 413         struct seq_file *m = file->private_data;
 414         struct snd_info_private_data *data = m->private;
 415         struct snd_info_entry *entry = data->entry;
 416
 417         if (data->wbuffer && entry->c.text.write)
 418                 entry->c.text.write(entry, data->wbuffer);
 419
 420         single_release(inode, file);
 421         kfree(data->rbuffer);
 422         if (data->wbuffer) {
 423                 kfree(data->wbuffer->buffer);
 424                 kfree(data->wbuffer);
 425         }
 426
 427         module_put(entry->module);
 428         kfree(data);
 429         return 0;
 430 }
 431
 432 static const struct file_operations snd_info_text_entry_ops =
 433 {
 434         .owner =                THIS_MODULE,
 435         .open =                 snd_info_text_entry_open,
 436         .release =              snd_info_text_entry_release,
 437         .write =                snd_info_text_entry_write,
 438         .llseek =               seq_lseek,
 439         .read =                 seq_read,
 440 };
 441
 442 static struct snd_info_entry *create_subdir(struct module *mod,
 443                                             const char *name)
 444 {
 445         struct snd_info_entry *entry;
 446
 447         entry = snd_info_create_module_entry(mod, name, NULL);
 448         if (!entry)
 449                 return NULL;
 450         entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
 451         if (snd_info_register(entry) < 0) {
 452                 snd_info_free_entry(entry);
 453                 return NULL;
 454         }
 455         return entry;
 456 }
 457
 458 static struct snd_info_entry *snd_info_create_entry(const char *name);
 459
 460 int __init snd_info_init(void)
 461 {
 462         snd_proc_root = snd_info_create_entry("asound");
 463         if (!snd_proc_root)
 464                 return -ENOMEM;
 465         snd_proc_root->mode = S_IFDIR | S_IRUGO | S_IXUGO;
 466         snd_proc_root->p = proc_mkdir("asound", NULL);
 467         if (!snd_proc_root->p)
 468                 goto error;
 469 #ifdef CONFIG_SND_OSSEMUL
 470         snd_oss_root = create_subdir(THIS_MODULE, "oss");
 471         if (!snd_oss_root)
 472                 goto error;
 473 #endif
 474 #if IS_ENABLED(CONFIG_SND_SEQUENCER)
 475         snd_seq_root = create_subdir(THIS_MODULE, "seq");
 476         if (!snd_seq_root)
 477                 goto error;
 478 #endif
 479         if (snd_info_version_init() < 0 ||
 480             snd_minor_info_init() < 0 ||
 481             snd_minor_info_oss_init() < 0 ||
 482             snd_card_info_init() < 0 ||
 483             snd_info_minor_register() < 0)
 484                 goto error;
 485         return 0;
 486
 487  error:
 488         snd_info_free_entry(snd_proc_root);
 489         return -ENOMEM;
 490 }
 491
 492 int __exit snd_info_done(void)
 493 {
 494         snd_info_free_entry(snd_proc_root);
 495         return 0;
 496 }
 497
 498 /*
 499  * create a card proc file
 500  * called from init.c
 501  */
 502 int snd_info_card_create(struct snd_card *card)
 503 {
 504         char str[8];
 505         struct snd_info_entry *entry;
 506
 507         if (snd_BUG_ON(!card))
 508                 return -ENXIO;
 509
 510         sprintf(str, "card%i", card->number);
 511         entry = create_subdir(card->module, str);
 512         if (!entry)
 513                 return -ENOMEM;
 514         card->proc_root = entry;
 515         return 0;
 516 }
 517
 518 /*
 519  * register the card proc file
 520  * called from init.c
 521  */
 522 int snd_info_card_register(struct snd_card *card)
 523 {
 524         struct proc_dir_entry *p;
 525
 526         if (snd_BUG_ON(!card))
 527                 return -ENXIO;
 528
 529         if (!strcmp(card->id, card->proc_root->name))
 530                 return 0;
 531
 532         p = proc_symlink(card->id, snd_proc_root->p, card->proc_root->name);
 533         if (p == NULL)
 534                 return -ENOMEM;
 535         card->proc_root_link = p;
 536         return 0;
 537 }
 538
 539 /*
 540  * called on card->id change
 541  */
 542 void snd_info_card_id_change(struct snd_card *card)
 543 {
 544         mutex_lock(&info_mutex);
 545         if (card->proc_root_link) {
 546                 proc_remove(card->proc_root_link);
 547                 card->proc_root_link = NULL;
 548         }
 549         if (strcmp(card->id, card->proc_root->name))
 550                 card->proc_root_link = proc_symlink(card->id,
 551                                                     snd_proc_root->p,
 552                                                     card->proc_root->name);
 553         mutex_unlock(&info_mutex);
 554 }
 555
 556 /*
 557  * de-register the card proc file
 558  * called from init.c
 559  */
 560 void snd_info_card_disconnect(struct snd_card *card)
 561 {
 562         if (!card)
 563                 return;
 564         mutex_lock(&info_mutex);
 565         proc_remove(card->proc_root_link);
 566         card->proc_root_link = NULL;
 567         if (card->proc_root)
 568                 snd_info_disconnect(card->proc_root);
 569         mutex_unlock(&info_mutex);
 570 }
 571
 572 /*
 573  * release the card proc file resources
 574  * called from init.c
 575  */
 576 int snd_info_card_free(struct snd_card *card)
 577 {
 578         if (!card)
 579                 return 0;
 580         snd_info_free_entry(card->proc_root);
 581         card->proc_root = NULL;
 582         return 0;
 583 }
 584
 585
 586 /**
 587  * snd_info_get_line - read one line from the procfs buffer
 588  * @buffer: the procfs buffer
 589  * @line: the buffer to store
 590  * @len: the max. buffer size
 591  *
 592  * Reads one line from the buffer and stores the string.
 593  *
 594  * Return: Zero if successful, or 1 if error or EOF.
 595  */
 596 int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
 597 {
 598         int c = -1;
 599
 600         if (snd_BUG_ON(!buffer || !buffer->buffer))
 601                 return 1;
 602         if (len <= 0 || buffer->stop || buffer->error)
 603                 return 1;
 604         while (!buffer->stop) {
 605                 c = buffer->buffer[buffer->curr++];
 606                 if (buffer->curr >= buffer->size)
 607                         buffer->stop = 1;
 608                 if (c == '\n')
 609                         break;
 610                 if (len > 1) {
 611                         len--;
 612                         *line++ = c;
 613                 }
 614         }
 615         *line = '\0';
 616         return 0;
 617 }
 618
 619 EXPORT_SYMBOL(snd_info_get_line);
 620
 621 /**
 622  * snd_info_get_str - parse a string token
 623  * @dest: the buffer to store the string token
 624  * @src: the original string
 625  * @len: the max. length of token - 1
 626  *
 627  * Parses the original string and copy a token to the given
 628  * string buffer.
 629  *
 630  * Return: The updated pointer of the original string so that
 631  * it can be used for the next call.
 632  */
 633 const char *snd_info_get_str(char *dest, const char *src, int len)
 634 {
 635         int c;
 636
 637         while (*src == ' ' || *src == '\t')
 638                 src++;
 639         if (*src == '"' || *src == '\'') {
 640                 c = *src++;
 641                 while (--len > 0 && *src && *src != c) {
 642                         *dest++ = *src++;
 643                 }
 644                 if (*src == c)
 645                         src++;
 646         } else {
 647                 while (--len > 0 && *src && *src != ' ' && *src != '\t') {
 648                         *dest++ = *src++;
 649                 }
 650         }
 651         *dest = 0;
 652         while (*src == ' ' || *src == '\t')
 653                 src++;
 654         return src;
 655 }
 656
 657 EXPORT_SYMBOL(snd_info_get_str);
 658
 659 /**
 660  * snd_info_create_entry - create an info entry
 661  * @name: the proc file name
 662  *
 663  * Creates an info entry with the given file name and initializes as
 664  * the default state.
 665  *
 666  * Usually called from other functions such as
 667  * snd_info_create_card_entry().
 668  *
 669  * Return: The pointer of the new instance, or %NULL on failure.
 670  */
 671 static struct snd_info_entry *snd_info_create_entry(const char *name)
 672 {
 673         struct snd_info_entry *entry;
 674         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 675         if (entry == NULL)
 676                 return NULL;
 677         entry->name = kstrdup(name, GFP_KERNEL);
 678         if (entry->name == NULL) {
 679                 kfree(entry);
 680                 return NULL;
 681         }
 682         entry->mode = S_IFREG | S_IRUGO;
 683         entry->content = SNDRV_INFO_CONTENT_TEXT;
 684         mutex_init(&entry->access);
 685         INIT_LIST_HEAD(&entry->children);
 686         INIT_LIST_HEAD(&entry->list);
 687         return entry;
 688 }
 689
 690 /**
 691  * snd_info_create_module_entry - create an info entry for the given module
 692  * @module: the module pointer
 693  * @name: the file name
 694  * @parent: the parent directory
 695  *
 696  * Creates a new info entry and assigns it to the given module.
 697  *
 698  * Return: The pointer of the new instance, or %NULL on failure.
 699  */
 700 struct snd_info_entry *snd_info_create_module_entry(struct module * module,
 701                                                const char *name,
 702                                                struct snd_info_entry *parent)
 703 {
 704         struct snd_info_entry *entry = snd_info_create_entry(name);
 705         if (entry) {
 706                 entry->module = module;
 707                 entry->parent = parent;
 708         }
 709         return entry;
 710 }
 711
 712 EXPORT_SYMBOL(snd_info_create_module_entry);
 713
 714 /**
 715  * snd_info_create_card_entry - create an info entry for the given card
 716  * @card: the card instance
 717  * @name: the file name
 718  * @parent: the parent directory
 719  *
 720  * Creates a new info entry and assigns it to the given card.
 721  *
 722  * Return: The pointer of the new instance, or %NULL on failure.
 723  */
 724 struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
 725                                              const char *name,
 726                                              struct snd_info_entry * parent)
 727 {
 728         struct snd_info_entry *entry = snd_info_create_entry(name);
 729         if (entry) {
 730                 entry->module = card->module;
 731                 entry->card = card;
 732                 entry->parent = parent;
 733         }
 734         return entry;
 735 }
 736
 737 EXPORT_SYMBOL(snd_info_create_card_entry);
 738
 739 static void snd_info_disconnect(struct snd_info_entry *entry)
 740 {
 741         struct snd_info_entry *p;
 742
 743         if (!entry->p)
 744                 return;
 745         list_for_each_entry(p, &entry->children, list)
 746                 snd_info_disconnect(p);
 747         proc_remove(entry->p);
 748         entry->p = NULL;
 749 }
 750
 751 /**
 752  * snd_info_free_entry - release the info entry
 753  * @entry: the info entry
 754  *
 755  * Releases the info entry.
 756  */
 757 void snd_info_free_entry(struct snd_info_entry * entry)
 758 {
 759         struct snd_info_entry *p, *n;
 760
 761         if (!entry)
 762                 return;
 763         if (entry->p) {
 764                 mutex_lock(&info_mutex);
 765                 snd_info_disconnect(entry);
 766                 mutex_unlock(&info_mutex);
 767         }
 768
 769         /* free all children at first */
 770         list_for_each_entry_safe(p, n, &entry->children, list)
 771                 snd_info_free_entry(p);
 772
 773         list_del(&entry->list);
 774         kfree(entry->name);
 775         if (entry->private_free)
 776                 entry->private_free(entry);
 777         kfree(entry);
 778 }
 779
 780 EXPORT_SYMBOL(snd_info_free_entry);
 781
 782 /**
 783  * snd_info_register - register the info entry
 784  * @entry: the info entry
 785  *
 786  * Registers the proc info entry.
 787  *
 788  * Return: Zero if successful, or a negative error code on failure.
 789  */
 790 int snd_info_register(struct snd_info_entry * entry)
 791 {
 792         struct proc_dir_entry *root, *p = NULL;
 793
 794         if (snd_BUG_ON(!entry))
 795                 return -ENXIO;
 796         root = entry->parent == NULL ? snd_proc_root->p : entry->parent->p;
 797         mutex_lock(&info_mutex);
 798         if (S_ISDIR(entry->mode)) {
 799                 p = proc_mkdir_mode(entry->name, entry->mode, root);
 800                 if (!p) {
 801                         mutex_unlock(&info_mutex);
 802                         return -ENOMEM;
 803                 }
 804         } else {
 805                 const struct file_operations *ops;
 806                 if (entry->content == SNDRV_INFO_CONTENT_DATA)
 807                         ops = &snd_info_entry_operations;
 808                 else
 809                         ops = &snd_info_text_entry_ops;
 810                 p = proc_create_data(entry->name, entry->mode, root,
 811                                      ops, entry);
 812                 if (!p) {
 813                         mutex_unlock(&info_mutex);
 814                         return -ENOMEM;
 815                 }
 816                 proc_set_size(p, entry->size);
 817         }
 818         entry->p = p;
 819         if (entry->parent)
 820                 list_add_tail(&entry->list, &entry->parent->children);
 821         mutex_unlock(&info_mutex);
 822         return 0;
 823 }
 824
 825 EXPORT_SYMBOL(snd_info_register);
 826
 827 /*
 828
 829  */
 830
 831 static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 832 {
 833         snd_iprintf(buffer,
 834                     "Advanced Linux Sound Architecture Driver Version k%s.\n",
 835                     init_utsname()->release);
 836 }
 837
 838 static int __init snd_info_version_init(void)
 839 {
 840         struct snd_info_entry *entry;
 841
 842         entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
 843         if (entry == NULL)
 844                 return -ENOMEM;
 845         entry->c.text.read = snd_info_version_read;
 846         return snd_info_register(entry); /* freed in error path */
 847 }