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 int snd_info_version_done(void);
  82 static void snd_info_disconnect(struct snd_info_entry *entry);
  83
  84 /*
  85
  86  */
  87
  88 static struct proc_dir_entry *snd_proc_root;
  89 struct snd_info_entry *snd_seq_root;
  90 EXPORT_SYMBOL(snd_seq_root);
  91
  92 #ifdef CONFIG_SND_OSSEMUL
  93 struct snd_info_entry *snd_oss_root;
  94 #endif
  95
  96 static int alloc_info_private(struct snd_info_entry *entry,
  97                               struct snd_info_private_data **ret)
  98 {
  99         struct snd_info_private_data *data;
 100
 101         if (!entry || !entry->p)
 102                 return -ENODEV;
 103         if (!try_module_get(entry->module))
 104                 return -EFAULT;
 105         data = kzalloc(sizeof(*data), GFP_KERNEL);
 106         if (!data) {
 107                 module_put(entry->module);
 108                 return -ENOMEM;
 109         }
 110         data->entry = entry;
 111         *ret = data;
 112         return 0;
 113 }
 114
 115 static bool valid_pos(loff_t pos, size_t count)
 116 {
 117         if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
 118                 return false;
 119         if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
 120                 return false;
 121         return true;
 122 }
 123
 124 /*
 125  * file ops for binary proc files
 126  */
 127 static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
 128 {
 129         struct snd_info_private_data *data;
 130         struct snd_info_entry *entry;
 131         loff_t ret = -EINVAL, size;
 132
 133         data = file->private_data;
 134         entry = data->entry;
 135         mutex_lock(&entry->access);
 136         if (entry->c.ops->llseek) {
 137                 offset = entry->c.ops->llseek(entry,
 138                                               data->file_private_data,
 139                                               file, offset, orig);
 140                 goto out;
 141         }
 142
 143         size = entry->size;
 144         switch (orig) {
 145         case SEEK_SET:
 146                 break;
 147         case SEEK_CUR:
 148                 offset += file->f_pos;
 149                 break;
 150         case SEEK_END:
 151                 if (!size)
 152                         goto out;
 153                 offset += size;
 154                 break;
 155         default:
 156                 goto out;
 157         }
 158         if (offset < 0)
 159                 goto out;
 160         if (size && offset > size)
 161                 offset = size;
 162         file->f_pos = offset;
 163         ret = offset;
 164  out:
 165         mutex_unlock(&entry->access);
 166         return ret;
 167 }
 168
 169 static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
 170                                    size_t count, loff_t * offset)
 171 {
 172         struct snd_info_private_data *data = file->private_data;
 173         struct snd_info_entry *entry = data->entry;
 174         size_t size;
 175         loff_t pos;
 176
 177         pos = *offset;
 178         if (!valid_pos(pos, count))
 179                 return -EIO;
 180         if (pos >= entry->size)
 181                 return 0;
 182         size = entry->size - pos;
 183         size = min(count, size);
 184         size = entry->c.ops->read(entry, data->file_private_data,
 185                                   file, buffer, size, pos);
 186         if ((ssize_t) size > 0)
 187                 *offset = pos + size;
 188         return size;
 189 }
 190
 191 static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
 192                                     size_t count, loff_t * offset)
 193 {
 194         struct snd_info_private_data *data = file->private_data;
 195         struct snd_info_entry *entry = data->entry;
 196         ssize_t size = 0;
 197         loff_t pos;
 198
 199         pos = *offset;
 200         if (!valid_pos(pos, count))
 201                 return -EIO;
 202         if (count > 0) {
 203                 size_t maxsize = entry->size - pos;
 204                 count = min(count, maxsize);
 205                 size = entry->c.ops->write(entry, data->file_private_data,
 206                                            file, buffer, count, pos);
 207         }
 208         if (size > 0)
 209                 *offset = pos + size;
 210         return size;
 211 }
 212
 213 static unsigned int snd_info_entry_poll(struct file *file, poll_table *wait)
 214 {
 215         struct snd_info_private_data *data = file->private_data;
 216         struct snd_info_entry *entry = data->entry;
 217         unsigned int mask = 0;
 218
 219         if (entry->c.ops->poll)
 220                 return entry->c.ops->poll(entry,
 221                                           data->file_private_data,
 222                                           file, wait);
 223         if (entry->c.ops->read)
 224                 mask |= POLLIN | POLLRDNORM;
 225         if (entry->c.ops->write)
 226                 mask |= POLLOUT | POLLWRNORM;
 227         return mask;
 228 }
 229
 230 static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
 231                                 unsigned long arg)
 232 {
 233         struct snd_info_private_data *data = file->private_data;
 234         struct snd_info_entry *entry = data->entry;
 235
 236         if (!entry->c.ops->ioctl)
 237                 return -ENOTTY;
 238         return entry->c.ops->ioctl(entry, data->file_private_data,
 239                                    file, cmd, arg);
 240 }
 241
 242 static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
 243 {
 244         struct inode *inode = file_inode(file);
 245         struct snd_info_private_data *data;
 246         struct snd_info_entry *entry;
 247
 248         data = file->private_data;
 249         if (data == NULL)
 250                 return 0;
 251         entry = data->entry;
 252         if (!entry->c.ops->mmap)
 253                 return -ENXIO;
 254         return entry->c.ops->mmap(entry, data->file_private_data,
 255                                   inode, file, vma);
 256 }
 257
 258 static int snd_info_entry_open(struct inode *inode, struct file *file)
 259 {
 260         struct snd_info_entry *entry = PDE_DATA(inode);
 261         struct snd_info_private_data *data;
 262         int mode, err;
 263
 264         mutex_lock(&info_mutex);
 265         err = alloc_info_private(entry, &data);
 266         if (err < 0)
 267                 goto unlock;
 268
 269         mode = file->f_flags & O_ACCMODE;
 270         if (((mode == O_RDONLY || mode == O_RDWR) && !entry->c.ops->read) ||
 271             ((mode == O_WRONLY || mode == O_RDWR) && !entry->c.ops->write)) {
 272                 err = -ENODEV;
 273                 goto error;
 274         }
 275
 276         if (entry->c.ops->open) {
 277                 err = entry->c.ops->open(entry, mode, &data->file_private_data);
 278                 if (err < 0)
 279                         goto error;
 280         }
 281
 282         file->private_data = data;
 283         mutex_unlock(&info_mutex);
 284         return 0;
 285
 286  error:
 287         kfree(data);
 288         module_put(entry->module);
 289  unlock:
 290         mutex_unlock(&info_mutex);
 291         return err;
 292 }
 293
 294 static int snd_info_entry_release(struct inode *inode, struct file *file)
 295 {
 296         struct snd_info_private_data *data = file->private_data;
 297         struct snd_info_entry *entry = data->entry;
 298
 299         if (entry->c.ops->release)
 300                 entry->c.ops->release(entry, file->f_flags & O_ACCMODE,
 301                                       data->file_private_data);
 302         module_put(entry->module);
 303         kfree(data);
 304         return 0;
 305 }
 306
 307 static const struct file_operations snd_info_entry_operations =
 308 {
 309         .owner =                THIS_MODULE,
 310         .llseek =               snd_info_entry_llseek,
 311         .read =                 snd_info_entry_read,
 312         .write =                snd_info_entry_write,
 313         .poll =                 snd_info_entry_poll,
 314         .unlocked_ioctl =       snd_info_entry_ioctl,
 315         .mmap =                 snd_info_entry_mmap,
 316         .open =                 snd_info_entry_open,
 317         .release =              snd_info_entry_release,
 318 };
 319
 320 /*
 321  * file ops for text proc files
 322  */
 323 static ssize_t snd_info_text_entry_write(struct file *file,
 324                                          const char __user *buffer,
 325                                          size_t count, loff_t *offset)
 326 {
 327         struct seq_file *m = file->private_data;
 328         struct snd_info_private_data *data = m->private;
 329         struct snd_info_entry *entry = data->entry;
 330         struct snd_info_buffer *buf;
 331         loff_t pos;
 332         size_t next;
 333         int err = 0;
 334
 335         pos = *offset;
 336         if (!valid_pos(pos, count))
 337                 return -EIO;
 338         next = pos + count;
 339         mutex_lock(&entry->access);
 340         buf = data->wbuffer;
 341         if (!buf) {
 342                 data->wbuffer = buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 343                 if (!buf) {
 344                         err = -ENOMEM;
 345                         goto error;
 346                 }
 347         }
 348         if (next > buf->len) {
 349                 char *nbuf = krealloc(buf->buffer, PAGE_ALIGN(next),
 350                                       GFP_KERNEL | __GFP_ZERO);
 351                 if (!nbuf) {
 352                         err = -ENOMEM;
 353                         goto error;
 354                 }
 355                 buf->buffer = nbuf;
 356                 buf->len = PAGE_ALIGN(next);
 357         }
 358         if (copy_from_user(buf->buffer + pos, buffer, count)) {
 359                 err = -EFAULT;
 360                 goto error;
 361         }
 362         buf->size = next;
 363  error:
 364         mutex_unlock(&entry->access);
 365         if (err < 0)
 366                 return err;
 367         *offset = next;
 368         return count;
 369 }
 370
 371 static int snd_info_seq_show(struct seq_file *seq, void *p)
 372 {
 373         struct snd_info_private_data *data = seq->private;
 374         struct snd_info_entry *entry = data->entry;
 375
 376         if (entry->c.text.read) {
 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                 kfree(data->wbuffer->buffer);
 431                 kfree(data->wbuffer);
 432         }
 433
 434         module_put(entry->module);
 435         kfree(data);
 436         return 0;
 437 }
 438
 439 static const struct file_operations snd_info_text_entry_ops =
 440 {
 441         .owner =                THIS_MODULE,
 442         .open =                 snd_info_text_entry_open,
 443         .release =              snd_info_text_entry_release,
 444         .write =                snd_info_text_entry_write,
 445         .llseek =               seq_lseek,
 446         .read =                 seq_read,
 447 };
 448
 449 static struct snd_info_entry *create_subdir(struct module *mod,
 450                                             const char *name)
 451 {
 452         struct snd_info_entry *entry;
 453
 454         entry = snd_info_create_module_entry(mod, name, NULL);
 455         if (!entry)
 456                 return NULL;
 457         entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
 458         if (snd_info_register(entry) < 0) {
 459                 snd_info_free_entry(entry);
 460                 return NULL;
 461         }
 462         return entry;
 463 }
 464
 465 int __init snd_info_init(void)
 466 {
 467         struct proc_dir_entry *p;
 468
 469         p = proc_mkdir("asound", NULL);
 470         if (p == NULL)
 471                 return -ENOMEM;
 472         snd_proc_root = p;
 473 #ifdef CONFIG_SND_OSSEMUL
 474         snd_oss_root = create_subdir(THIS_MODULE, "oss");
 475         if (!snd_oss_root)
 476                 goto error;
 477 #endif
 478 #if IS_ENABLED(CONFIG_SND_SEQUENCER)
 479         snd_seq_root = create_subdir(THIS_MODULE, "seq");
 480         if (!snd_seq_root)
 481                 goto error;
 482 #endif
 483         snd_info_version_init();
 484         snd_minor_info_init();
 485         snd_minor_info_oss_init();
 486         snd_card_info_init();
 487         return 0;
 488
 489  error:
 490 #ifdef CONFIG_SND_OSSEMUL
 491         snd_info_free_entry(snd_oss_root);
 492 #endif
 493         proc_remove(snd_proc_root);
 494         return -ENOMEM;
 495 }
 496
 497 int __exit snd_info_done(void)
 498 {
 499         snd_card_info_done();
 500         snd_minor_info_oss_done();
 501         snd_minor_info_done();
 502         snd_info_version_done();
 503         if (snd_proc_root) {
 504 #if IS_ENABLED(CONFIG_SND_SEQUENCER)
 505                 snd_info_free_entry(snd_seq_root);
 506 #endif
 507 #ifdef CONFIG_SND_OSSEMUL
 508                 snd_info_free_entry(snd_oss_root);
 509 #endif
 510                 proc_remove(snd_proc_root);
 511         }
 512         return 0;
 513 }
 514
 515 /*
 516
 517  */
 518
 519
 520 /*
 521  * create a card proc file
 522  * called from init.c
 523  */
 524 int snd_info_card_create(struct snd_card *card)
 525 {
 526         char str[8];
 527         struct snd_info_entry *entry;
 528
 529         if (snd_BUG_ON(!card))
 530                 return -ENXIO;
 531
 532         sprintf(str, "card%i", card->number);
 533         entry = create_subdir(card->module, str);
 534         if (!entry)
 535                 return -ENOMEM;
 536         card->proc_root = entry;
 537         return 0;
 538 }
 539
 540 /*
 541  * register the card proc file
 542  * called from init.c
 543  */
 544 int snd_info_card_register(struct snd_card *card)
 545 {
 546         struct proc_dir_entry *p;
 547
 548         if (snd_BUG_ON(!card))
 549                 return -ENXIO;
 550
 551         if (!strcmp(card->id, card->proc_root->name))
 552                 return 0;
 553
 554         p = proc_symlink(card->id, snd_proc_root, card->proc_root->name);
 555         if (p == NULL)
 556                 return -ENOMEM;
 557         card->proc_root_link = p;
 558         return 0;
 559 }
 560
 561 /*
 562  * called on card->id change
 563  */
 564 void snd_info_card_id_change(struct snd_card *card)
 565 {
 566         mutex_lock(&info_mutex);
 567         if (card->proc_root_link) {
 568                 proc_remove(card->proc_root_link);
 569                 card->proc_root_link = NULL;
 570         }
 571         if (strcmp(card->id, card->proc_root->name))
 572                 card->proc_root_link = proc_symlink(card->id,
 573                                                     snd_proc_root,
 574                                                     card->proc_root->name);
 575         mutex_unlock(&info_mutex);
 576 }
 577
 578 /*
 579  * de-register the card proc file
 580  * called from init.c
 581  */
 582 void snd_info_card_disconnect(struct snd_card *card)
 583 {
 584         if (!card)
 585                 return;
 586         mutex_lock(&info_mutex);
 587         proc_remove(card->proc_root_link);
 588         card->proc_root_link = NULL;
 589         if (card->proc_root)
 590                 snd_info_disconnect(card->proc_root);
 591         mutex_unlock(&info_mutex);
 592 }
 593
 594 /*
 595  * release the card proc file resources
 596  * called from init.c
 597  */
 598 int snd_info_card_free(struct snd_card *card)
 599 {
 600         if (!card)
 601                 return 0;
 602         snd_info_free_entry(card->proc_root);
 603         card->proc_root = NULL;
 604         return 0;
 605 }
 606
 607
 608 /**
 609  * snd_info_get_line - read one line from the procfs buffer
 610  * @buffer: the procfs buffer
 611  * @line: the buffer to store
 612  * @len: the max. buffer size
 613  *
 614  * Reads one line from the buffer and stores the string.
 615  *
 616  * Return: Zero if successful, or 1 if error or EOF.
 617  */
 618 int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
 619 {
 620         int c = -1;
 621
 622         if (snd_BUG_ON(!buffer || !buffer->buffer))
 623                 return 1;
 624         if (len <= 0 || buffer->stop || buffer->error)
 625                 return 1;
 626         while (!buffer->stop) {
 627                 c = buffer->buffer[buffer->curr++];
 628                 if (buffer->curr >= buffer->size)
 629                         buffer->stop = 1;
 630                 if (c == '\n')
 631                         break;
 632                 if (len > 1) {
 633                         len--;
 634                         *line++ = c;
 635                 }
 636         }
 637         *line = '\0';
 638         return 0;
 639 }
 640
 641 EXPORT_SYMBOL(snd_info_get_line);
 642
 643 /**
 644  * snd_info_get_str - parse a string token
 645  * @dest: the buffer to store the string token
 646  * @src: the original string
 647  * @len: the max. length of token - 1
 648  *
 649  * Parses the original string and copy a token to the given
 650  * string buffer.
 651  *
 652  * Return: The updated pointer of the original string so that
 653  * it can be used for the next call.
 654  */
 655 const char *snd_info_get_str(char *dest, const char *src, int len)
 656 {
 657         int c;
 658
 659         while (*src == ' ' || *src == '\t')
 660                 src++;
 661         if (*src == '"' || *src == '\'') {
 662                 c = *src++;
 663                 while (--len > 0 && *src && *src != c) {
 664                         *dest++ = *src++;
 665                 }
 666                 if (*src == c)
 667                         src++;
 668         } else {
 669                 while (--len > 0 && *src && *src != ' ' && *src != '\t') {
 670                         *dest++ = *src++;
 671                 }
 672         }
 673         *dest = 0;
 674         while (*src == ' ' || *src == '\t')
 675                 src++;
 676         return src;
 677 }
 678
 679 EXPORT_SYMBOL(snd_info_get_str);
 680
 681 /**
 682  * snd_info_create_entry - create an info entry
 683  * @name: the proc file name
 684  *
 685  * Creates an info entry with the given file name and initializes as
 686  * the default state.
 687  *
 688  * Usually called from other functions such as
 689  * snd_info_create_card_entry().
 690  *
 691  * Return: The pointer of the new instance, or %NULL on failure.
 692  */
 693 static struct snd_info_entry *snd_info_create_entry(const char *name)
 694 {
 695         struct snd_info_entry *entry;
 696         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 697         if (entry == NULL)
 698                 return NULL;
 699         entry->name = kstrdup(name, GFP_KERNEL);
 700         if (entry->name == NULL) {
 701                 kfree(entry);
 702                 return NULL;
 703         }
 704         entry->mode = S_IFREG | S_IRUGO;
 705         entry->content = SNDRV_INFO_CONTENT_TEXT;
 706         mutex_init(&entry->access);
 707         INIT_LIST_HEAD(&entry->children);
 708         INIT_LIST_HEAD(&entry->list);
 709         return entry;
 710 }
 711
 712 /**
 713  * snd_info_create_module_entry - create an info entry for the given module
 714  * @module: the module pointer
 715  * @name: the file name
 716  * @parent: the parent directory
 717  *
 718  * Creates a new info entry and assigns it to the given module.
 719  *
 720  * Return: The pointer of the new instance, or %NULL on failure.
 721  */
 722 struct snd_info_entry *snd_info_create_module_entry(struct module * module,
 723                                                const char *name,
 724                                                struct snd_info_entry *parent)
 725 {
 726         struct snd_info_entry *entry = snd_info_create_entry(name);
 727         if (entry) {
 728                 entry->module = module;
 729                 entry->parent = parent;
 730         }
 731         return entry;
 732 }
 733
 734 EXPORT_SYMBOL(snd_info_create_module_entry);
 735
 736 /**
 737  * snd_info_create_card_entry - create an info entry for the given card
 738  * @card: the card instance
 739  * @name: the file name
 740  * @parent: the parent directory
 741  *
 742  * Creates a new info entry and assigns it to the given card.
 743  *
 744  * Return: The pointer of the new instance, or %NULL on failure.
 745  */
 746 struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
 747                                              const char *name,
 748                                              struct snd_info_entry * parent)
 749 {
 750         struct snd_info_entry *entry = snd_info_create_entry(name);
 751         if (entry) {
 752                 entry->module = card->module;
 753                 entry->card = card;
 754                 entry->parent = parent;
 755         }
 756         return entry;
 757 }
 758
 759 EXPORT_SYMBOL(snd_info_create_card_entry);
 760
 761 static void snd_info_disconnect(struct snd_info_entry *entry)
 762 {
 763         struct snd_info_entry *p, *n;
 764
 765         if (!entry->p)
 766                 return;
 767         list_for_each_entry_safe(p, n, &entry->children, list)
 768                 snd_info_disconnect(p);
 769         list_del_init(&entry->list);
 770         proc_remove(entry->p);
 771         entry->p = NULL;
 772 }
 773
 774 /**
 775  * snd_info_free_entry - release the info entry
 776  * @entry: the info entry
 777  *
 778  * Releases the info entry.
 779  */
 780 void snd_info_free_entry(struct snd_info_entry * entry)
 781 {
 782         struct snd_info_entry *p, *n;
 783
 784         if (!entry)
 785                 return;
 786         if (entry->p) {
 787                 mutex_lock(&info_mutex);
 788                 snd_info_disconnect(entry);
 789                 mutex_unlock(&info_mutex);
 790         }
 791
 792         /* free all children at first */
 793         list_for_each_entry_safe(p, n, &entry->children, list)
 794                 snd_info_free_entry(p);
 795
 796         kfree(entry->name);
 797         if (entry->private_free)
 798                 entry->private_free(entry);
 799         kfree(entry);
 800 }
 801
 802 EXPORT_SYMBOL(snd_info_free_entry);
 803
 804 /**
 805  * snd_info_register - register the info entry
 806  * @entry: the info entry
 807  *
 808  * Registers the proc info entry.
 809  *
 810  * Return: Zero if successful, or a negative error code on failure.
 811  */
 812 int snd_info_register(struct snd_info_entry * entry)
 813 {
 814         struct proc_dir_entry *root, *p = NULL;
 815
 816         if (snd_BUG_ON(!entry))
 817                 return -ENXIO;
 818         root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
 819         mutex_lock(&info_mutex);
 820         if (S_ISDIR(entry->mode)) {
 821                 p = proc_mkdir_mode(entry->name, entry->mode, root);
 822                 if (!p) {
 823                         mutex_unlock(&info_mutex);
 824                         return -ENOMEM;
 825                 }
 826         } else {
 827                 const struct file_operations *ops;
 828                 if (entry->content == SNDRV_INFO_CONTENT_DATA)
 829                         ops = &snd_info_entry_operations;
 830                 else
 831                         ops = &snd_info_text_entry_ops;
 832                 p = proc_create_data(entry->name, entry->mode, root,
 833                                      ops, entry);
 834                 if (!p) {
 835                         mutex_unlock(&info_mutex);
 836                         return -ENOMEM;
 837                 }
 838                 proc_set_size(p, entry->size);
 839         }
 840         entry->p = p;
 841         if (entry->parent)
 842                 list_add_tail(&entry->list, &entry->parent->children);
 843         mutex_unlock(&info_mutex);
 844         return 0;
 845 }
 846
 847 EXPORT_SYMBOL(snd_info_register);
 848
 849 /*
 850
 851  */
 852
 853 static struct snd_info_entry *snd_info_version_entry;
 854
 855 static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 856 {
 857         snd_iprintf(buffer,
 858                     "Advanced Linux Sound Architecture Driver Version k%s.\n",
 859                     init_utsname()->release);
 860 }
 861
 862 static int __init snd_info_version_init(void)
 863 {
 864         struct snd_info_entry *entry;
 865
 866         entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
 867         if (entry == NULL)
 868                 return -ENOMEM;
 869         entry->c.text.read = snd_info_version_read;
 870         if (snd_info_register(entry) < 0) {
 871                 snd_info_free_entry(entry);
 872                 return -ENOMEM;
 873         }
 874         snd_info_version_entry = entry;
 875         return 0;
 876 }
 877
 878 static int __exit snd_info_version_done(void)
 879 {
 880         snd_info_free_entry(snd_info_version_entry);
 881         return 0;
 882 }
 883
 884 #endif /* CONFIG_PROC_FS */