linux/sound/core/info.c
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   1/*
   2 *  Information interface for ALSA driver
   3 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   4 *
   5 *
   6 *   This program is free software; you can redistribute it and/or modify
   7 *   it under the terms of the GNU General Public License as published by
   8 *   the Free Software Foundation; either version 2 of the License, or
   9 *   (at your option) any later version.
  10 *
  11 *   This program is distributed in the hope that it will be useful,
  12 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 *   GNU General Public License for more details.
  15 *
  16 *   You should have received a copy of the GNU General Public License
  17 *   along with this program; if not, write to the Free Software
  18 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19 *
  20 */
  21
  22#include <linux/init.h>
  23#include <linux/time.h>
  24#include <linux/mm.h>
  25#include <linux/slab.h>
  26#include <linux/string.h>
  27#include <linux/module.h>
  28#include <sound/core.h>
  29#include <sound/minors.h>
  30#include <sound/info.h>
  31#include <linux/utsname.h>
  32#include <linux/proc_fs.h>
  33#include <linux/mutex.h>
  34#include <stdarg.h>
  35
  36int 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
  65static DEFINE_MUTEX(info_mutex);
  66
  67struct 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
  74static int snd_info_version_init(void);
  75static void snd_info_disconnect(struct snd_info_entry *entry);
  76
  77/*
  78
  79 */
  80
  81static struct snd_info_entry *snd_proc_root;
  82struct snd_info_entry *snd_seq_root;
  83EXPORT_SYMBOL(snd_seq_root);
  84
  85#ifdef CONFIG_SND_OSSEMUL
  86struct snd_info_entry *snd_oss_root;
  87#endif
  88
  89static 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
 108static 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 */
 120static 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
 162static 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
 184static 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
 206static 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
 223static 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
 235static 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
 251static 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
 287static 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
 300static 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 */
 316static 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 = krealloc(buf->buffer, PAGE_ALIGN(next),
 348                                      GFP_KERNEL | __GFP_ZERO);
 349                if (!nbuf) {
 350                        err = -ENOMEM;
 351                        goto error;
 352                }
 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
 369static 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
 383static 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
 418static 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
 439static 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
 449static 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
 465static struct snd_info_entry *
 466snd_info_create_entry(const char *name, struct snd_info_entry *parent);
 467
 468int __init snd_info_init(void)
 469{
 470        snd_proc_root = snd_info_create_entry("asound", NULL);
 471        if (!snd_proc_root)
 472                return -ENOMEM;
 473        snd_proc_root->mode = S_IFDIR | S_IRUGO | S_IXUGO;
 474        snd_proc_root->p = proc_mkdir("asound", NULL);
 475        if (!snd_proc_root->p)
 476                goto error;
 477#ifdef CONFIG_SND_OSSEMUL
 478        snd_oss_root = create_subdir(THIS_MODULE, "oss");
 479        if (!snd_oss_root)
 480                goto error;
 481#endif
 482#if IS_ENABLED(CONFIG_SND_SEQUENCER)
 483        snd_seq_root = create_subdir(THIS_MODULE, "seq");
 484        if (!snd_seq_root)
 485                goto error;
 486#endif
 487        if (snd_info_version_init() < 0 ||
 488            snd_minor_info_init() < 0 ||
 489            snd_minor_info_oss_init() < 0 ||
 490            snd_card_info_init() < 0 ||
 491            snd_info_minor_register() < 0)
 492                goto error;
 493        return 0;
 494
 495 error:
 496        snd_info_free_entry(snd_proc_root);
 497        return -ENOMEM;
 498}
 499
 500int __exit snd_info_done(void)
 501{
 502        snd_info_free_entry(snd_proc_root);
 503        return 0;
 504}
 505
 506/*
 507 * create a card proc file
 508 * called from init.c
 509 */
 510int snd_info_card_create(struct snd_card *card)
 511{
 512        char str[8];
 513        struct snd_info_entry *entry;
 514
 515        if (snd_BUG_ON(!card))
 516                return -ENXIO;
 517
 518        sprintf(str, "card%i", card->number);
 519        entry = create_subdir(card->module, str);
 520        if (!entry)
 521                return -ENOMEM;
 522        card->proc_root = entry;
 523        return 0;
 524}
 525
 526/* register all pending info entries */
 527static int snd_info_register_recursive(struct snd_info_entry *entry)
 528{
 529        struct snd_info_entry *p;
 530        int err;
 531
 532        if (!entry->p) {
 533                err = snd_info_register(entry);
 534                if (err < 0)
 535                        return err;
 536        }
 537
 538        list_for_each_entry(p, &entry->children, list) {
 539                err = snd_info_register_recursive(p);
 540                if (err < 0)
 541                        return err;
 542        }
 543
 544        return 0;
 545}
 546
 547/*
 548 * register the card proc file
 549 * called from init.c
 550 * can be called multiple times for reinitialization
 551 */
 552int snd_info_card_register(struct snd_card *card)
 553{
 554        struct proc_dir_entry *p;
 555        int err;
 556
 557        if (snd_BUG_ON(!card))
 558                return -ENXIO;
 559
 560        err = snd_info_register_recursive(card->proc_root);
 561        if (err < 0)
 562                return err;
 563
 564        if (!strcmp(card->id, card->proc_root->name))
 565                return 0;
 566
 567        if (card->proc_root_link)
 568                return 0;
 569        p = proc_symlink(card->id, snd_proc_root->p, card->proc_root->name);
 570        if (!p)
 571                return -ENOMEM;
 572        card->proc_root_link = p;
 573        return 0;
 574}
 575
 576/*
 577 * called on card->id change
 578 */
 579void snd_info_card_id_change(struct snd_card *card)
 580{
 581        mutex_lock(&info_mutex);
 582        if (card->proc_root_link) {
 583                proc_remove(card->proc_root_link);
 584                card->proc_root_link = NULL;
 585        }
 586        if (strcmp(card->id, card->proc_root->name))
 587                card->proc_root_link = proc_symlink(card->id,
 588                                                    snd_proc_root->p,
 589                                                    card->proc_root->name);
 590        mutex_unlock(&info_mutex);
 591}
 592
 593/*
 594 * de-register the card proc file
 595 * called from init.c
 596 */
 597void snd_info_card_disconnect(struct snd_card *card)
 598{
 599        if (!card)
 600                return;
 601        mutex_lock(&info_mutex);
 602        proc_remove(card->proc_root_link);
 603        card->proc_root_link = NULL;
 604        if (card->proc_root)
 605                snd_info_disconnect(card->proc_root);
 606        mutex_unlock(&info_mutex);
 607}
 608
 609/*
 610 * release the card proc file resources
 611 * called from init.c
 612 */
 613int snd_info_card_free(struct snd_card *card)
 614{
 615        if (!card)
 616                return 0;
 617        snd_info_free_entry(card->proc_root);
 618        card->proc_root = NULL;
 619        return 0;
 620}
 621
 622
 623/**
 624 * snd_info_get_line - read one line from the procfs buffer
 625 * @buffer: the procfs buffer
 626 * @line: the buffer to store
 627 * @len: the max. buffer size
 628 *
 629 * Reads one line from the buffer and stores the string.
 630 *
 631 * Return: Zero if successful, or 1 if error or EOF.
 632 */
 633int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
 634{
 635        int c = -1;
 636
 637        if (snd_BUG_ON(!buffer || !buffer->buffer))
 638                return 1;
 639        if (len <= 0 || buffer->stop || buffer->error)
 640                return 1;
 641        while (!buffer->stop) {
 642                c = buffer->buffer[buffer->curr++];
 643                if (buffer->curr >= buffer->size)
 644                        buffer->stop = 1;
 645                if (c == '\n')
 646                        break;
 647                if (len > 1) {
 648                        len--;
 649                        *line++ = c;
 650                }
 651        }
 652        *line = '\0';
 653        return 0;
 654}
 655
 656EXPORT_SYMBOL(snd_info_get_line);
 657
 658/**
 659 * snd_info_get_str - parse a string token
 660 * @dest: the buffer to store the string token
 661 * @src: the original string
 662 * @len: the max. length of token - 1
 663 *
 664 * Parses the original string and copy a token to the given
 665 * string buffer.
 666 *
 667 * Return: The updated pointer of the original string so that
 668 * it can be used for the next call.
 669 */
 670const char *snd_info_get_str(char *dest, const char *src, int len)
 671{
 672        int c;
 673
 674        while (*src == ' ' || *src == '\t')
 675                src++;
 676        if (*src == '"' || *src == '\'') {
 677                c = *src++;
 678                while (--len > 0 && *src && *src != c) {
 679                        *dest++ = *src++;
 680                }
 681                if (*src == c)
 682                        src++;
 683        } else {
 684                while (--len > 0 && *src && *src != ' ' && *src != '\t') {
 685                        *dest++ = *src++;
 686                }
 687        }
 688        *dest = 0;
 689        while (*src == ' ' || *src == '\t')
 690                src++;
 691        return src;
 692}
 693
 694EXPORT_SYMBOL(snd_info_get_str);
 695
 696/*
 697 * snd_info_create_entry - create an info entry
 698 * @name: the proc file name
 699 * @parent: the parent directory
 700 *
 701 * Creates an info entry with the given file name and initializes as
 702 * the default state.
 703 *
 704 * Usually called from other functions such as
 705 * snd_info_create_card_entry().
 706 *
 707 * Return: The pointer of the new instance, or %NULL on failure.
 708 */
 709static struct snd_info_entry *
 710snd_info_create_entry(const char *name, struct snd_info_entry *parent)
 711{
 712        struct snd_info_entry *entry;
 713        entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 714        if (entry == NULL)
 715                return NULL;
 716        entry->name = kstrdup(name, GFP_KERNEL);
 717        if (entry->name == NULL) {
 718                kfree(entry);
 719                return NULL;
 720        }
 721        entry->mode = S_IFREG | S_IRUGO;
 722        entry->content = SNDRV_INFO_CONTENT_TEXT;
 723        mutex_init(&entry->access);
 724        INIT_LIST_HEAD(&entry->children);
 725        INIT_LIST_HEAD(&entry->list);
 726        entry->parent = parent;
 727        if (parent)
 728                list_add_tail(&entry->list, &parent->children);
 729        return entry;
 730}
 731
 732/**
 733 * snd_info_create_module_entry - create an info entry for the given module
 734 * @module: the module pointer
 735 * @name: the file name
 736 * @parent: the parent directory
 737 *
 738 * Creates a new info entry and assigns it to the given module.
 739 *
 740 * Return: The pointer of the new instance, or %NULL on failure.
 741 */
 742struct snd_info_entry *snd_info_create_module_entry(struct module * module,
 743                                               const char *name,
 744                                               struct snd_info_entry *parent)
 745{
 746        struct snd_info_entry *entry = snd_info_create_entry(name, parent);
 747        if (entry)
 748                entry->module = module;
 749        return entry;
 750}
 751
 752EXPORT_SYMBOL(snd_info_create_module_entry);
 753
 754/**
 755 * snd_info_create_card_entry - create an info entry for the given card
 756 * @card: the card instance
 757 * @name: the file name
 758 * @parent: the parent directory
 759 *
 760 * Creates a new info entry and assigns it to the given card.
 761 *
 762 * Return: The pointer of the new instance, or %NULL on failure.
 763 */
 764struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
 765                                             const char *name,
 766                                             struct snd_info_entry * parent)
 767{
 768        struct snd_info_entry *entry = snd_info_create_entry(name, parent);
 769        if (entry) {
 770                entry->module = card->module;
 771                entry->card = card;
 772        }
 773        return entry;
 774}
 775
 776EXPORT_SYMBOL(snd_info_create_card_entry);
 777
 778static void snd_info_disconnect(struct snd_info_entry *entry)
 779{
 780        struct snd_info_entry *p;
 781
 782        if (!entry->p)
 783                return;
 784        list_for_each_entry(p, &entry->children, list)
 785                snd_info_disconnect(p);
 786        proc_remove(entry->p);
 787        entry->p = NULL;
 788}
 789
 790/**
 791 * snd_info_free_entry - release the info entry
 792 * @entry: the info entry
 793 *
 794 * Releases the info entry.
 795 */
 796void snd_info_free_entry(struct snd_info_entry * entry)
 797{
 798        struct snd_info_entry *p, *n;
 799
 800        if (!entry)
 801                return;
 802        if (entry->p) {
 803                mutex_lock(&info_mutex);
 804                snd_info_disconnect(entry);
 805                mutex_unlock(&info_mutex);
 806        }
 807
 808        /* free all children at first */
 809        list_for_each_entry_safe(p, n, &entry->children, list)
 810                snd_info_free_entry(p);
 811
 812        list_del(&entry->list);
 813        kfree(entry->name);
 814        if (entry->private_free)
 815                entry->private_free(entry);
 816        kfree(entry);
 817}
 818
 819EXPORT_SYMBOL(snd_info_free_entry);
 820
 821/**
 822 * snd_info_register - register the info entry
 823 * @entry: the info entry
 824 *
 825 * Registers the proc info entry.
 826 *
 827 * Return: Zero if successful, or a negative error code on failure.
 828 */
 829int snd_info_register(struct snd_info_entry * entry)
 830{
 831        struct proc_dir_entry *root, *p = NULL;
 832
 833        if (snd_BUG_ON(!entry))
 834                return -ENXIO;
 835        root = entry->parent == NULL ? snd_proc_root->p : entry->parent->p;
 836        mutex_lock(&info_mutex);
 837        if (S_ISDIR(entry->mode)) {
 838                p = proc_mkdir_mode(entry->name, entry->mode, root);
 839                if (!p) {
 840                        mutex_unlock(&info_mutex);
 841                        return -ENOMEM;
 842                }
 843        } else {
 844                const struct file_operations *ops;
 845                if (entry->content == SNDRV_INFO_CONTENT_DATA)
 846                        ops = &snd_info_entry_operations;
 847                else
 848                        ops = &snd_info_text_entry_ops;
 849                p = proc_create_data(entry->name, entry->mode, root,
 850                                     ops, entry);
 851                if (!p) {
 852                        mutex_unlock(&info_mutex);
 853                        return -ENOMEM;
 854                }
 855                proc_set_size(p, entry->size);
 856        }
 857        entry->p = p;
 858        mutex_unlock(&info_mutex);
 859        return 0;
 860}
 861
 862EXPORT_SYMBOL(snd_info_register);
 863
 864/*
 865
 866 */
 867
 868static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 869{
 870        snd_iprintf(buffer,
 871                    "Advanced Linux Sound Architecture Driver Version k%s.\n",
 872                    init_utsname()->release);
 873}
 874
 875static int __init snd_info_version_init(void)
 876{
 877        struct snd_info_entry *entry;
 878
 879        entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
 880        if (entry == NULL)
 881                return -ENOMEM;
 882        entry->c.text.read = snd_info_version_read;
 883        return snd_info_register(entry); /* freed in error path */
 884}
 885