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 __poll_t 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         __poll_t 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 |= EPOLLIN | EPOLLRDNORM;
 218         if (entry->c.ops->write)
 219                 mask |= EPOLLOUT | EPOLLWRNORM;
 220         return mask;
 221 }
 222
 223 static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
 224                                 unsigned long arg)
 225 {
 226         struct snd_info_private_data *data = file->private_data;
 227         struct snd_info_entry *entry = data->entry;
 228
 229         if (!entry->c.ops->ioctl)
 230                 return -ENOTTY;
 231         return entry->c.ops->ioctl(entry, data->file_private_data,
 232                                    file, cmd, arg);
 233 }
 234
 235 static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
 236 {
 237         struct inode *inode = file_inode(file);
 238         struct snd_info_private_data *data;
 239         struct snd_info_entry *entry;
 240
 241         data = file->private_data;
 242         if (data == NULL)
 243                 return 0;
 244         entry = data->entry;
 245         if (!entry->c.ops->mmap)
 246                 return -ENXIO;
 247         return entry->c.ops->mmap(entry, data->file_private_data,
 248                                   inode, file, vma);
 249 }
 250
 251 static int snd_info_entry_open(struct inode *inode, struct file *file)
 252 {
 253         struct snd_info_entry *entry = PDE_DATA(inode);
 254         struct snd_info_private_data *data;
 255         int mode, err;
 256
 257         mutex_lock(&info_mutex);
 258         err = alloc_info_private(entry, &data);
 259         if (err < 0)
 260                 goto unlock;
 261
 262         mode = file->f_flags & O_ACCMODE;
 263         if (((mode == O_RDONLY || mode == O_RDWR) && !entry->c.ops->read) ||
 264             ((mode == O_WRONLY || mode == O_RDWR) && !entry->c.ops->write)) {
 265                 err = -ENODEV;
 266                 goto error;
 267         }
 268
 269         if (entry->c.ops->open) {
 270                 err = entry->c.ops->open(entry, mode, &data->file_private_data);
 271                 if (err < 0)
 272                         goto error;
 273         }
 274
 275         file->private_data = data;
 276         mutex_unlock(&info_mutex);
 277         return 0;
 278
 279  error:
 280         kfree(data);
 281         module_put(entry->module);
 282  unlock:
 283         mutex_unlock(&info_mutex);
 284         return err;
 285 }
 286
 287 static int snd_info_entry_release(struct inode *inode, struct file *file)
 288 {
 289         struct snd_info_private_data *data = file->private_data;
 290         struct snd_info_entry *entry = data->entry;
 291
 292         if (entry->c.ops->release)
 293                 entry->c.ops->release(entry, file->f_flags & O_ACCMODE,
 294                                       data->file_private_data);
 295         module_put(entry->module);
 296         kfree(data);
 297         return 0;
 298 }
 299
 300 static const struct file_operations snd_info_entry_operations =
 301 {
 302         .owner =                THIS_MODULE,
 303         .llseek =               snd_info_entry_llseek,
 304         .read =                 snd_info_entry_read,
 305         .write =                snd_info_entry_write,
 306         .poll =                 snd_info_entry_poll,
 307         .unlocked_ioctl =       snd_info_entry_ioctl,
 308         .mmap =                 snd_info_entry_mmap,
 309         .open =                 snd_info_entry_open,
 310         .release =              snd_info_entry_release,
 311 };
 312
 313 /*
 314  * file ops for text proc files
 315  */
 316 static ssize_t snd_info_text_entry_write(struct file *file,
 317                                          const char __user *buffer,
 318                                          size_t count, loff_t *offset)
 319 {
 320         struct seq_file *m = file->private_data;
 321         struct snd_info_private_data *data = m->private;
 322         struct snd_info_entry *entry = data->entry;
 323         struct snd_info_buffer *buf;
 324         loff_t pos;
 325         size_t next;
 326         int err = 0;
 327
 328         if (!entry->c.text.write)
 329                 return -EIO;
 330         pos = *offset;
 331         if (!valid_pos(pos, count))
 332                 return -EIO;
 333         next = pos + count;
 334         /* don't handle too large text inputs */
 335         if (next > 16 * 1024)
 336                 return -EIO;
 337         mutex_lock(&entry->access);
 338         buf = data->wbuffer;
 339         if (!buf) {
 340                 data->wbuffer = buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 341                 if (!buf) {
 342                         err = -ENOMEM;
 343                         goto error;
 344                 }
 345         }
 346         if (next > buf->len) {
 347                 char *nbuf = kvzalloc(PAGE_ALIGN(next), GFP_KERNEL);
 348                 if (!nbuf) {
 349                         err = -ENOMEM;
 350                         goto error;
 351                 }
 352                 kvfree(buf->buffer);
 353                 buf->buffer = nbuf;
 354                 buf->len = PAGE_ALIGN(next);
 355         }
 356         if (copy_from_user(buf->buffer + pos, buffer, count)) {
 357                 err = -EFAULT;
 358                 goto error;
 359         }
 360         buf->size = next;
 361  error:
 362         mutex_unlock(&entry->access);
 363         if (err < 0)
 364                 return err;
 365         *offset = next;
 366         return count;
 367 }
 368
 369 static int snd_info_seq_show(struct seq_file *seq, void *p)
 370 {
 371         struct snd_info_private_data *data = seq->private;
 372         struct snd_info_entry *entry = data->entry;
 373
 374         if (!entry->c.text.read) {
 375                 return -EIO;
 376         } else {
 377                 data->rbuffer->buffer = (char *)seq; /* XXX hack! */
 378                 entry->c.text.read(entry, data->rbuffer);
 379         }
 380         return 0;
 381 }
 382
 383 static int snd_info_text_entry_open(struct inode *inode, struct file *file)
 384 {
 385         struct snd_info_entry *entry = PDE_DATA(inode);
 386         struct snd_info_private_data *data;
 387         int err;
 388
 389         mutex_lock(&info_mutex);
 390         err = alloc_info_private(entry, &data);
 391         if (err < 0)
 392                 goto unlock;
 393
 394         data->rbuffer = kzalloc(sizeof(*data->rbuffer), GFP_KERNEL);
 395         if (!data->rbuffer) {
 396                 err = -ENOMEM;
 397                 goto error;
 398         }
 399         if (entry->size)
 400                 err = single_open_size(file, snd_info_seq_show, data,
 401                                        entry->size);
 402         else
 403                 err = single_open(file, snd_info_seq_show, data);
 404         if (err < 0)
 405                 goto error;
 406         mutex_unlock(&info_mutex);
 407         return 0;
 408
 409  error:
 410         kfree(data->rbuffer);
 411         kfree(data);
 412         module_put(entry->module);
 413  unlock:
 414         mutex_unlock(&info_mutex);
 415         return err;
 416 }
 417
 418 static int snd_info_text_entry_release(struct inode *inode, struct file *file)
 419 {
 420         struct seq_file *m = file->private_data;
 421         struct snd_info_private_data *data = m->private;
 422         struct snd_info_entry *entry = data->entry;
 423
 424         if (data->wbuffer && entry->c.text.write)
 425                 entry->c.text.write(entry, data->wbuffer);
 426
 427         single_release(inode, file);
 428         kfree(data->rbuffer);
 429         if (data->wbuffer) {
 430                 kvfree(data->wbuffer->buffer);
 431                 kfree(data->wbuffer);
 432         }
 433
 434         module_put(entry->module);
 435         kfree(data);
 436         return 0;
 437 }
 438
 439 static const struct file_operations snd_info_text_entry_ops =
 440 {
 441         .owner =                THIS_MODULE,
 442         .open =                 snd_info_text_entry_open,
 443         .release =              snd_info_text_entry_release,
 444         .write =                snd_info_text_entry_write,
 445         .llseek =               seq_lseek,
 446         .read =                 seq_read,
 447 };
 448
 449 static struct snd_info_entry *create_subdir(struct module *mod,
 450                                             const char *name)
 451 {
 452         struct snd_info_entry *entry;
 453
 454         entry = snd_info_create_module_entry(mod, name, NULL);
 455         if (!entry)
 456                 return NULL;
 457         entry->mode = S_IFDIR | 0555;
 458         if (snd_info_register(entry) < 0) {
 459                 snd_info_free_entry(entry);
 460                 return NULL;
 461         }
 462         return entry;
 463 }
 464
 465 static struct snd_info_entry *
 466 snd_info_create_entry(const char *name, struct snd_info_entry *parent,
 467                       struct module *module);
 468
 469 int __init snd_info_init(void)
 470 {
 471         snd_proc_root = snd_info_create_entry("asound", NULL, THIS_MODULE);
 472         if (!snd_proc_root)
 473                 return -ENOMEM;
 474         snd_proc_root->mode = S_IFDIR | 0555;
 475         snd_proc_root->p = proc_mkdir("asound", NULL);
 476         if (!snd_proc_root->p)
 477                 goto error;
 478 #ifdef CONFIG_SND_OSSEMUL
 479         snd_oss_root = create_subdir(THIS_MODULE, "oss");
 480         if (!snd_oss_root)
 481                 goto error;
 482 #endif
 483 #if IS_ENABLED(CONFIG_SND_SEQUENCER)
 484         snd_seq_root = create_subdir(THIS_MODULE, "seq");
 485         if (!snd_seq_root)
 486                 goto error;
 487 #endif
 488         if (snd_info_version_init() < 0 ||
 489             snd_minor_info_init() < 0 ||
 490             snd_minor_info_oss_init() < 0 ||
 491             snd_card_info_init() < 0 ||
 492             snd_info_minor_register() < 0)
 493                 goto error;
 494         return 0;
 495
 496  error:
 497         snd_info_free_entry(snd_proc_root);
 498         return -ENOMEM;
 499 }
 500
 501 int __exit snd_info_done(void)
 502 {
 503         snd_info_free_entry(snd_proc_root);
 504         return 0;
 505 }
 506
 507 static void snd_card_id_read(struct snd_info_entry *entry,
 508                              struct snd_info_buffer *buffer)
 509 {
 510         struct snd_card *card = entry->private_data;
 511
 512         snd_iprintf(buffer, "%s\n", card->id);
 513 }
 514
 515 /*
 516  * create a card proc file
 517  * called from init.c
 518  */
 519 int snd_info_card_create(struct snd_card *card)
 520 {
 521         char str[8];
 522         struct snd_info_entry *entry;
 523
 524         if (snd_BUG_ON(!card))
 525                 return -ENXIO;
 526
 527         sprintf(str, "card%i", card->number);
 528         entry = create_subdir(card->module, str);
 529         if (!entry)
 530                 return -ENOMEM;
 531         card->proc_root = entry;
 532
 533         return snd_card_ro_proc_new(card, "id", card, snd_card_id_read);
 534 }
 535
 536 /*
 537  * register the card proc file
 538  * called from init.c
 539  * can be called multiple times for reinitialization
 540  */
 541 int snd_info_card_register(struct snd_card *card)
 542 {
 543         struct proc_dir_entry *p;
 544         int err;
 545
 546         if (snd_BUG_ON(!card))
 547                 return -ENXIO;
 548
 549         err = snd_info_register(card->proc_root);
 550         if (err < 0)
 551                 return err;
 552
 553         if (!strcmp(card->id, card->proc_root->name))
 554                 return 0;
 555
 556         if (card->proc_root_link)
 557                 return 0;
 558         p = proc_symlink(card->id, snd_proc_root->p, card->proc_root->name);
 559         if (!p)
 560                 return -ENOMEM;
 561         card->proc_root_link = p;
 562         return 0;
 563 }
 564
 565 /*
 566  * called on card->id change
 567  */
 568 void snd_info_card_id_change(struct snd_card *card)
 569 {
 570         mutex_lock(&info_mutex);
 571         if (card->proc_root_link) {
 572                 proc_remove(card->proc_root_link);
 573                 card->proc_root_link = NULL;
 574         }
 575         if (strcmp(card->id, card->proc_root->name))
 576                 card->proc_root_link = proc_symlink(card->id,
 577                                                     snd_proc_root->p,
 578                                                     card->proc_root->name);
 579         mutex_unlock(&info_mutex);
 580 }
 581
 582 /*
 583  * de-register the card proc file
 584  * called from init.c
 585  */
 586 void snd_info_card_disconnect(struct snd_card *card)
 587 {
 588         if (!card)
 589                 return;
 590         mutex_lock(&info_mutex);
 591         proc_remove(card->proc_root_link);
 592         card->proc_root_link = NULL;
 593         if (card->proc_root)
 594                 snd_info_disconnect(card->proc_root);
 595         mutex_unlock(&info_mutex);
 596 }
 597
 598 /*
 599  * release the card proc file resources
 600  * called from init.c
 601  */
 602 int snd_info_card_free(struct snd_card *card)
 603 {
 604         if (!card)
 605                 return 0;
 606         snd_info_free_entry(card->proc_root);
 607         card->proc_root = NULL;
 608         return 0;
 609 }
 610
 611
 612 /**
 613  * snd_info_get_line - read one line from the procfs buffer
 614  * @buffer: the procfs buffer
 615  * @line: the buffer to store
 616  * @len: the max. buffer size
 617  *
 618  * Reads one line from the buffer and stores the string.
 619  *
 620  * Return: Zero if successful, or 1 if error or EOF.
 621  */
 622 int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
 623 {
 624         int c = -1;
 625
 626         if (snd_BUG_ON(!buffer || !buffer->buffer))
 627                 return 1;
 628         if (len <= 0 || buffer->stop || buffer->error)
 629                 return 1;
 630         while (!buffer->stop) {
 631                 c = buffer->buffer[buffer->curr++];
 632                 if (buffer->curr >= buffer->size)
 633                         buffer->stop = 1;
 634                 if (c == '\n')
 635                         break;
 636                 if (len > 1) {
 637                         len--;
 638                         *line++ = c;
 639                 }
 640         }
 641         *line = '\0';
 642         return 0;
 643 }
 644 EXPORT_SYMBOL(snd_info_get_line);
 645
 646 /**
 647  * snd_info_get_str - parse a string token
 648  * @dest: the buffer to store the string token
 649  * @src: the original string
 650  * @len: the max. length of token - 1
 651  *
 652  * Parses the original string and copy a token to the given
 653  * string buffer.
 654  *
 655  * Return: The updated pointer of the original string so that
 656  * it can be used for the next call.
 657  */
 658 const char *snd_info_get_str(char *dest, const char *src, int len)
 659 {
 660         int c;
 661
 662         while (*src == ' ' || *src == '\t')
 663                 src++;
 664         if (*src == '"' || *src == '\'') {
 665                 c = *src++;
 666                 while (--len > 0 && *src && *src != c) {
 667                         *dest++ = *src++;
 668                 }
 669                 if (*src == c)
 670                         src++;
 671         } else {
 672                 while (--len > 0 && *src && *src != ' ' && *src != '\t') {
 673                         *dest++ = *src++;
 674                 }
 675         }
 676         *dest = 0;
 677         while (*src == ' ' || *src == '\t')
 678                 src++;
 679         return src;
 680 }
 681 EXPORT_SYMBOL(snd_info_get_str);
 682
 683 /*
 684  * snd_info_create_entry - create an info entry
 685  * @name: the proc file name
 686  * @parent: the parent directory
 687  *
 688  * Creates an info entry with the given file name and initializes as
 689  * the default state.
 690  *
 691  * Usually called from other functions such as
 692  * snd_info_create_card_entry().
 693  *
 694  * Return: The pointer of the new instance, or %NULL on failure.
 695  */
 696 static struct snd_info_entry *
 697 snd_info_create_entry(const char *name, struct snd_info_entry *parent,
 698                       struct module *module)
 699 {
 700         struct snd_info_entry *entry;
 701         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 702         if (entry == NULL)
 703                 return NULL;
 704         entry->name = kstrdup(name, GFP_KERNEL);
 705         if (entry->name == NULL) {
 706                 kfree(entry);
 707                 return NULL;
 708         }
 709         entry->mode = S_IFREG | 0444;
 710         entry->content = SNDRV_INFO_CONTENT_TEXT;
 711         mutex_init(&entry->access);
 712         INIT_LIST_HEAD(&entry->children);
 713         INIT_LIST_HEAD(&entry->list);
 714         entry->parent = parent;
 715         entry->module = module;
 716         if (parent) {
 717                 mutex_lock(&parent->access);
 718                 list_add_tail(&entry->list, &parent->children);
 719                 mutex_unlock(&parent->access);
 720         }
 721         return entry;
 722 }
 723
 724 /**
 725  * snd_info_create_module_entry - create an info entry for the given module
 726  * @module: the module pointer
 727  * @name: the file name
 728  * @parent: the parent directory
 729  *
 730  * Creates a new info entry and assigns it to the given module.
 731  *
 732  * Return: The pointer of the new instance, or %NULL on failure.
 733  */
 734 struct snd_info_entry *snd_info_create_module_entry(struct module * module,
 735                                                const char *name,
 736                                                struct snd_info_entry *parent)
 737 {
 738         if (!parent)
 739                 parent = snd_proc_root;
 740         return snd_info_create_entry(name, parent, module);
 741 }
 742 EXPORT_SYMBOL(snd_info_create_module_entry);
 743
 744 /**
 745  * snd_info_create_card_entry - create an info entry for the given card
 746  * @card: the card instance
 747  * @name: the file name
 748  * @parent: the parent directory
 749  *
 750  * Creates a new info entry and assigns it to the given card.
 751  *
 752  * Return: The pointer of the new instance, or %NULL on failure.
 753  */
 754 struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
 755                                              const char *name,
 756                                              struct snd_info_entry * parent)
 757 {
 758         if (!parent)
 759                 parent = card->proc_root;
 760         return snd_info_create_entry(name, parent, card->module);
 761 }
 762 EXPORT_SYMBOL(snd_info_create_card_entry);
 763
 764 static void snd_info_disconnect(struct snd_info_entry *entry)
 765 {
 766         struct snd_info_entry *p;
 767
 768         if (!entry->p)
 769                 return;
 770         list_for_each_entry(p, &entry->children, list)
 771                 snd_info_disconnect(p);
 772         proc_remove(entry->p);
 773         entry->p = NULL;
 774 }
 775
 776 /**
 777  * snd_info_free_entry - release the info entry
 778  * @entry: the info entry
 779  *
 780  * Releases the info entry.
 781  */
 782 void snd_info_free_entry(struct snd_info_entry * entry)
 783 {
 784         struct snd_info_entry *p, *n;
 785
 786         if (!entry)
 787                 return;
 788         if (entry->p) {
 789                 mutex_lock(&info_mutex);
 790                 snd_info_disconnect(entry);
 791                 mutex_unlock(&info_mutex);
 792         }
 793
 794         /* free all children at first */
 795         list_for_each_entry_safe(p, n, &entry->children, list)
 796                 snd_info_free_entry(p);
 797
 798         p = entry->parent;
 799         if (p) {
 800                 mutex_lock(&p->access);
 801                 list_del(&entry->list);
 802                 mutex_unlock(&p->access);
 803         }
 804         kfree(entry->name);
 805         if (entry->private_free)
 806                 entry->private_free(entry);
 807         kfree(entry);
 808 }
 809 EXPORT_SYMBOL(snd_info_free_entry);
 810
 811 static int __snd_info_register(struct snd_info_entry *entry)
 812 {
 813         struct proc_dir_entry *root, *p = NULL;
 814
 815         if (snd_BUG_ON(!entry))
 816                 return -ENXIO;
 817         root = entry->parent == NULL ? snd_proc_root->p : entry->parent->p;
 818         mutex_lock(&info_mutex);
 819         if (entry->p || !root)
 820                 goto unlock;
 821         if (S_ISDIR(entry->mode)) {
 822                 p = proc_mkdir_mode(entry->name, entry->mode, root);
 823                 if (!p) {
 824                         mutex_unlock(&info_mutex);
 825                         return -ENOMEM;
 826                 }
 827         } else {
 828                 const struct file_operations *ops;
 829                 if (entry->content == SNDRV_INFO_CONTENT_DATA)
 830                         ops = &snd_info_entry_operations;
 831                 else
 832                         ops = &snd_info_text_entry_ops;
 833                 p = proc_create_data(entry->name, entry->mode, root,
 834                                      ops, entry);
 835                 if (!p) {
 836                         mutex_unlock(&info_mutex);
 837                         return -ENOMEM;
 838                 }
 839                 proc_set_size(p, entry->size);
 840         }
 841         entry->p = p;
 842  unlock:
 843         mutex_unlock(&info_mutex);
 844         return 0;
 845 }
 846
 847 /**
 848  * snd_info_register - register the info entry
 849  * @entry: the info entry
 850  *
 851  * Registers the proc info entry.
 852  * The all children entries are registered recursively.
 853  *
 854  * Return: Zero if successful, or a negative error code on failure.
 855  */
 856 int snd_info_register(struct snd_info_entry *entry)
 857 {
 858         struct snd_info_entry *p;
 859         int err;
 860
 861         if (!entry->p) {
 862                 err = __snd_info_register(entry);
 863                 if (err < 0)
 864                         return err;
 865         }
 866
 867         list_for_each_entry(p, &entry->children, list) {
 868                 err = snd_info_register(p);
 869                 if (err < 0)
 870                         return err;
 871         }
 872
 873         return 0;
 874 }
 875 EXPORT_SYMBOL(snd_info_register);
 876
 877 /**
 878  * snd_card_rw_proc_new - Create a read/write text proc file entry for the card
 879  * @card: the card instance
 880  * @name: the file name
 881  * @private_data: the arbitrary private data
 882  * @read: the read callback
 883  * @write: the write callback, NULL for read-only
 884  *
 885  * This proc file entry will be registered via snd_card_register() call, and
 886  * it will be removed automatically at the card removal, too.
 887  */
 888 int snd_card_rw_proc_new(struct snd_card *card, const char *name,
 889                          void *private_data,
 890                          void (*read)(struct snd_info_entry *,
 891                                       struct snd_info_buffer *),
 892                          void (*write)(struct snd_info_entry *entry,
 893                                        struct snd_info_buffer *buffer))
 894 {
 895         struct snd_info_entry *entry;
 896
 897         entry = snd_info_create_card_entry(card, name, card->proc_root);
 898         if (!entry)
 899                 return -ENOMEM;
 900         snd_info_set_text_ops(entry, private_data, read);
 901         if (write) {
 902                 entry->mode |= 0200;
 903                 entry->c.text.write = write;
 904         }
 905         return 0;
 906 }
 907 EXPORT_SYMBOL_GPL(snd_card_rw_proc_new);
 908
 909 /*
 910
 911  */
 912
 913 static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 914 {
 915         snd_iprintf(buffer,
 916                     "Advanced Linux Sound Architecture Driver Version k%s.\n",
 917                     init_utsname()->release);
 918 }
 919
 920 static int __init snd_info_version_init(void)
 921 {
 922         struct snd_info_entry *entry;
 923
 924         entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
 925         if (entry == NULL)
 926                 return -ENOMEM;
 927         entry->c.text.read = snd_info_version_read;
 928         return snd_info_register(entry); /* freed in error path */
 929 }