sound/core/info.c

   1 /*
   2  *  Information interface for ALSA driver
   3  *  Copyright (c) by Jaroslav Kysela <perex@suse.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 <sound/driver.h>
  23 #include <linux/init.h>
  24 #include <linux/time.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/string.h>
  27 #include <sound/core.h>
  28 #include <sound/minors.h>
  29 #include <sound/info.h>
  30 #include <sound/version.h>
  31 #include <linux/proc_fs.h>
  32 #include <linux/mutex.h>
  33 #include <stdarg.h>
  34
  35 /*
  36  *
  37  */
  38
  39 #ifdef CONFIG_PROC_FS
  40
  41 int snd_info_check_reserved_words(const char *str)
  42 {
  43         static char *reserved[] =
  44         {
  45                 "version",
  46                 "meminfo",
  47                 "memdebug",
  48                 "detect",
  49                 "devices",
  50                 "oss",
  51                 "cards",
  52                 "timers",
  53                 "synth",
  54                 "pcm",
  55                 "seq",
  56                 NULL
  57         };
  58         char **xstr = reserved;
  59
  60         while (*xstr) {
  61                 if (!strcmp(*xstr, str))
  62                         return 0;
  63                 xstr++;
  64         }
  65         if (!strncmp(str, "card", 4))
  66                 return 0;
  67         return 1;
  68 }
  69
  70 static DEFINE_MUTEX(info_mutex);
  71
  72 struct snd_info_private_data {
  73         struct snd_info_buffer *rbuffer;
  74         struct snd_info_buffer *wbuffer;
  75         struct snd_info_entry *entry;
  76         void *file_private_data;
  77 };
  78
  79 static int snd_info_version_init(void);
  80 static int snd_info_version_done(void);
  81 static void snd_info_disconnect(struct snd_info_entry *entry);
  82
  83
  84 /* resize the proc r/w buffer */
  85 static int resize_info_buffer(struct snd_info_buffer *buffer,
  86                               unsigned int nsize)
  87 {
  88         char *nbuf;
  89
  90         nsize = PAGE_ALIGN(nsize);
  91         nbuf = kmalloc(nsize, GFP_KERNEL);
  92         if (! nbuf)
  93                 return -ENOMEM;
  94
  95         memcpy(nbuf, buffer->buffer, buffer->len);
  96         kfree(buffer->buffer);
  97         buffer->buffer = nbuf;
  98         buffer->len = nsize;
  99         return 0;
 100 }
 101
 102 /**
 103  * snd_iprintf - printf on the procfs buffer
 104  * @buffer: the procfs buffer
 105  * @fmt: the printf format
 106  *
 107  * Outputs the string on the procfs buffer just like printf().
 108  *
 109  * Returns the size of output string.
 110  */
 111 int snd_iprintf(struct snd_info_buffer *buffer, char *fmt,...)
 112 {
 113         va_list args;
 114         int len, res;
 115         int err = 0;
 116
 117         might_sleep();
 118         if (buffer->stop || buffer->error)
 119                 return 0;
 120         len = buffer->len - buffer->size;
 121         va_start(args, fmt);
 122         for (;;) {
 123                 va_list ap;
 124                 va_copy(ap, args);
 125                 res = vsnprintf(buffer->buffer + buffer->curr, len, fmt, ap);
 126                 va_end(ap);
 127                 if (res < len)
 128                         break;
 129                 err = resize_info_buffer(buffer, buffer->len + PAGE_SIZE);
 130                 if (err < 0)
 131                         break;
 132                 len = buffer->len - buffer->size;
 133         }
 134         va_end(args);
 135
 136         if (err < 0)
 137                 return err;
 138         buffer->curr += res;
 139         buffer->size += res;
 140         return res;
 141 }
 142
 143 EXPORT_SYMBOL(snd_iprintf);
 144
 145 /*
 146
 147  */
 148
 149 static struct proc_dir_entry *snd_proc_root;
 150 struct snd_info_entry *snd_seq_root;
 151 EXPORT_SYMBOL(snd_seq_root);
 152
 153 #ifdef CONFIG_SND_OSSEMUL
 154 struct snd_info_entry *snd_oss_root;
 155 #endif
 156
 157 static inline void snd_info_entry_prepare(struct proc_dir_entry *de)
 158 {
 159         de->owner = THIS_MODULE;
 160 }
 161
 162 static void snd_remove_proc_entry(struct proc_dir_entry *parent,
 163                                   struct proc_dir_entry *de)
 164 {
 165         if (de)
 166                 remove_proc_entry(de->name, parent);
 167 }
 168
 169 static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
 170 {
 171         struct snd_info_private_data *data;
 172         struct snd_info_entry *entry;
 173         loff_t ret;
 174
 175         data = file->private_data;
 176         entry = data->entry;
 177         lock_kernel();
 178         switch (entry->content) {
 179         case SNDRV_INFO_CONTENT_TEXT:
 180                 switch (orig) {
 181                 case SEEK_SET:
 182                         file->f_pos = offset;
 183                         ret = file->f_pos;
 184                         goto out;
 185                 case SEEK_CUR:
 186                         file->f_pos += offset;
 187                         ret = file->f_pos;
 188                         goto out;
 189                 case SEEK_END:
 190                 default:
 191                         ret = -EINVAL;
 192                         goto out;
 193                 }
 194                 break;
 195         case SNDRV_INFO_CONTENT_DATA:
 196                 if (entry->c.ops->llseek) {
 197                         ret = entry->c.ops->llseek(entry,
 198                                                     data->file_private_data,
 199                                                     file, offset, orig);
 200                         goto out;
 201                 }
 202                 break;
 203         }
 204         ret = -ENXIO;
 205 out:
 206         unlock_kernel();
 207         return ret;
 208 }
 209
 210 static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
 211                                    size_t count, loff_t * offset)
 212 {
 213         struct snd_info_private_data *data;
 214         struct snd_info_entry *entry;
 215         struct snd_info_buffer *buf;
 216         size_t size = 0;
 217         loff_t pos;
 218
 219         data = file->private_data;
 220         snd_assert(data != NULL, return -ENXIO);
 221         pos = *offset;
 222         if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
 223                 return -EIO;
 224         if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
 225                 return -EIO;
 226         entry = data->entry;
 227         switch (entry->content) {
 228         case SNDRV_INFO_CONTENT_TEXT:
 229                 buf = data->rbuffer;
 230                 if (buf == NULL)
 231                         return -EIO;
 232                 if (pos >= buf->size)
 233                         return 0;
 234                 size = buf->size - pos;
 235                 size = min(count, size);
 236                 if (copy_to_user(buffer, buf->buffer + pos, size))
 237                         return -EFAULT;
 238                 break;
 239         case SNDRV_INFO_CONTENT_DATA:
 240                 if (entry->c.ops->read)
 241                         size = entry->c.ops->read(entry,
 242                                                   data->file_private_data,
 243                                                   file, buffer, count, pos);
 244                 break;
 245         }
 246         if ((ssize_t) size > 0)
 247                 *offset = pos + size;
 248         return size;
 249 }
 250
 251 static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
 252                                     size_t count, loff_t * offset)
 253 {
 254         struct snd_info_private_data *data;
 255         struct snd_info_entry *entry;
 256         struct snd_info_buffer *buf;
 257         ssize_t size = 0;
 258         loff_t pos;
 259
 260         data = file->private_data;
 261         snd_assert(data != NULL, return -ENXIO);
 262         entry = data->entry;
 263         pos = *offset;
 264         if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
 265                 return -EIO;
 266         if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
 267                 return -EIO;
 268         switch (entry->content) {
 269         case SNDRV_INFO_CONTENT_TEXT:
 270                 buf = data->wbuffer;
 271                 if (buf == NULL)
 272                         return -EIO;
 273                 mutex_lock(&entry->access);
 274                 if (pos + count >= buf->len) {
 275                         if (resize_info_buffer(buf, pos + count)) {
 276                                 mutex_unlock(&entry->access);
 277                                 return -ENOMEM;
 278                         }
 279                 }
 280                 if (copy_from_user(buf->buffer + pos, buffer, count)) {
 281                         mutex_unlock(&entry->access);
 282                         return -EFAULT;
 283                 }
 284                 buf->size = pos + count;
 285                 mutex_unlock(&entry->access);
 286                 size = count;
 287                 break;
 288         case SNDRV_INFO_CONTENT_DATA:
 289                 if (entry->c.ops->write)
 290                         size = entry->c.ops->write(entry,
 291                                                    data->file_private_data,
 292                                                    file, buffer, count, pos);
 293                 break;
 294         }
 295         if ((ssize_t) size > 0)
 296                 *offset = pos + size;
 297         return size;
 298 }
 299
 300 static int snd_info_entry_open(struct inode *inode, struct file *file)
 301 {
 302         struct snd_info_entry *entry;
 303         struct snd_info_private_data *data;
 304         struct snd_info_buffer *buffer;
 305         struct proc_dir_entry *p;
 306         int mode, err;
 307
 308         mutex_lock(&info_mutex);
 309         p = PDE(inode);
 310         entry = p == NULL ? NULL : (struct snd_info_entry *)p->data;
 311         if (entry == NULL || ! entry->p) {
 312                 mutex_unlock(&info_mutex);
 313                 return -ENODEV;
 314         }
 315         if (!try_module_get(entry->module)) {
 316                 err = -EFAULT;
 317                 goto __error1;
 318         }
 319         mode = file->f_flags & O_ACCMODE;
 320         if (mode == O_RDONLY || mode == O_RDWR) {
 321                 if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
 322                      entry->c.ops->read == NULL)) {
 323                         err = -ENODEV;
 324                         goto __error;
 325                 }
 326         }
 327         if (mode == O_WRONLY || mode == O_RDWR) {
 328                 if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
 329                      entry->c.ops->write == NULL)) {
 330                         err = -ENODEV;
 331                         goto __error;
 332                 }
 333         }
 334         data = kzalloc(sizeof(*data), GFP_KERNEL);
 335         if (data == NULL) {
 336                 err = -ENOMEM;
 337                 goto __error;
 338         }
 339         data->entry = entry;
 340         switch (entry->content) {
 341         case SNDRV_INFO_CONTENT_TEXT:
 342                 if (mode == O_RDONLY || mode == O_RDWR) {
 343                         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 344                         if (buffer == NULL)
 345                                 goto __nomem;
 346                         data->rbuffer = buffer;
 347                         buffer->len = PAGE_SIZE;
 348                         buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
 349                         if (buffer->buffer == NULL)
 350                                 goto __nomem;
 351                 }
 352                 if (mode == O_WRONLY || mode == O_RDWR) {
 353                         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 354                         if (buffer == NULL)
 355                                 goto __nomem;
 356                         data->wbuffer = buffer;
 357                         buffer->len = PAGE_SIZE;
 358                         buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
 359                         if (buffer->buffer == NULL)
 360                                 goto __nomem;
 361                 }
 362                 break;
 363         case SNDRV_INFO_CONTENT_DATA:   /* data */
 364                 if (entry->c.ops->open) {
 365                         if ((err = entry->c.ops->open(entry, mode,
 366                                                       &data->file_private_data)) < 0) {
 367                                 kfree(data);
 368                                 goto __error;
 369                         }
 370                 }
 371                 break;
 372         }
 373         file->private_data = data;
 374         mutex_unlock(&info_mutex);
 375         if (entry->content == SNDRV_INFO_CONTENT_TEXT &&
 376             (mode == O_RDONLY || mode == O_RDWR)) {
 377                 if (entry->c.text.read) {
 378                         mutex_lock(&entry->access);
 379                         entry->c.text.read(entry, data->rbuffer);
 380                         mutex_unlock(&entry->access);
 381                 }
 382         }
 383         return 0;
 384
 385  __nomem:
 386         if (data->rbuffer) {
 387                 kfree(data->rbuffer->buffer);
 388                 kfree(data->rbuffer);
 389         }
 390         if (data->wbuffer) {
 391                 kfree(data->wbuffer->buffer);
 392                 kfree(data->wbuffer);
 393         }
 394         kfree(data);
 395         err = -ENOMEM;
 396       __error:
 397         module_put(entry->module);
 398       __error1:
 399         mutex_unlock(&info_mutex);
 400         return err;
 401 }
 402
 403 static int snd_info_entry_release(struct inode *inode, struct file *file)
 404 {
 405         struct snd_info_entry *entry;
 406         struct snd_info_private_data *data;
 407         int mode;
 408
 409         mode = file->f_flags & O_ACCMODE;
 410         data = file->private_data;
 411         entry = data->entry;
 412         switch (entry->content) {
 413         case SNDRV_INFO_CONTENT_TEXT:
 414                 if (data->rbuffer) {
 415                         kfree(data->rbuffer->buffer);
 416                         kfree(data->rbuffer);
 417                 }
 418                 if (data->wbuffer) {
 419                         if (entry->c.text.write) {
 420                                 entry->c.text.write(entry, data->wbuffer);
 421                                 if (data->wbuffer->error) {
 422                                         snd_printk(KERN_WARNING "data write error to %s (%i)\n",
 423                                                 entry->name,
 424                                                 data->wbuffer->error);
 425                                 }
 426                         }
 427                         kfree(data->wbuffer->buffer);
 428                         kfree(data->wbuffer);
 429                 }
 430                 break;
 431         case SNDRV_INFO_CONTENT_DATA:
 432                 if (entry->c.ops->release)
 433                         entry->c.ops->release(entry, mode,
 434                                               data->file_private_data);
 435                 break;
 436         }
 437         module_put(entry->module);
 438         kfree(data);
 439         return 0;
 440 }
 441
 442 static unsigned int snd_info_entry_poll(struct file *file, poll_table * wait)
 443 {
 444         struct snd_info_private_data *data;
 445         struct snd_info_entry *entry;
 446         unsigned int mask;
 447
 448         data = file->private_data;
 449         if (data == NULL)
 450                 return 0;
 451         entry = data->entry;
 452         mask = 0;
 453         switch (entry->content) {
 454         case SNDRV_INFO_CONTENT_DATA:
 455                 if (entry->c.ops->poll)
 456                         return entry->c.ops->poll(entry,
 457                                                   data->file_private_data,
 458                                                   file, wait);
 459                 if (entry->c.ops->read)
 460                         mask |= POLLIN | POLLRDNORM;
 461                 if (entry->c.ops->write)
 462                         mask |= POLLOUT | POLLWRNORM;
 463                 break;
 464         }
 465         return mask;
 466 }
 467
 468 static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
 469                                 unsigned long arg)
 470 {
 471         struct snd_info_private_data *data;
 472         struct snd_info_entry *entry;
 473
 474         data = file->private_data;
 475         if (data == NULL)
 476                 return 0;
 477         entry = data->entry;
 478         switch (entry->content) {
 479         case SNDRV_INFO_CONTENT_DATA:
 480                 if (entry->c.ops->ioctl)
 481                         return entry->c.ops->ioctl(entry,
 482                                                    data->file_private_data,
 483                                                    file, cmd, arg);
 484                 break;
 485         }
 486         return -ENOTTY;
 487 }
 488
 489 static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
 490 {
 491         struct inode *inode = file->f_path.dentry->d_inode;
 492         struct snd_info_private_data *data;
 493         struct snd_info_entry *entry;
 494
 495         data = file->private_data;
 496         if (data == NULL)
 497                 return 0;
 498         entry = data->entry;
 499         switch (entry->content) {
 500         case SNDRV_INFO_CONTENT_DATA:
 501                 if (entry->c.ops->mmap)
 502                         return entry->c.ops->mmap(entry,
 503                                                   data->file_private_data,
 504                                                   inode, file, vma);
 505                 break;
 506         }
 507         return -ENXIO;
 508 }
 509
 510 static const struct file_operations snd_info_entry_operations =
 511 {
 512         .owner =                THIS_MODULE,
 513         .llseek =               snd_info_entry_llseek,
 514         .read =                 snd_info_entry_read,
 515         .write =                snd_info_entry_write,
 516         .poll =                 snd_info_entry_poll,
 517         .unlocked_ioctl =       snd_info_entry_ioctl,
 518         .mmap =                 snd_info_entry_mmap,
 519         .open =                 snd_info_entry_open,
 520         .release =              snd_info_entry_release,
 521 };
 522
 523 /**
 524  * snd_create_proc_entry - create a procfs entry
 525  * @name: the name of the proc file
 526  * @mode: the file permission bits, S_Ixxx
 527  * @parent: the parent proc-directory entry
 528  *
 529  * Creates a new proc file entry with the given name and permission
 530  * on the given directory.
 531  *
 532  * Returns the pointer of new instance or NULL on failure.
 533  */
 534 static struct proc_dir_entry *snd_create_proc_entry(const char *name, mode_t mode,
 535                                                     struct proc_dir_entry *parent)
 536 {
 537         struct proc_dir_entry *p;
 538         p = create_proc_entry(name, mode, parent);
 539         if (p)
 540                 snd_info_entry_prepare(p);
 541         return p;
 542 }
 543
 544 int __init snd_info_init(void)
 545 {
 546         struct proc_dir_entry *p;
 547
 548         p = snd_create_proc_entry("asound", S_IFDIR | S_IRUGO | S_IXUGO, &proc_root);
 549         if (p == NULL)
 550                 return -ENOMEM;
 551         snd_proc_root = p;
 552 #ifdef CONFIG_SND_OSSEMUL
 553         {
 554                 struct snd_info_entry *entry;
 555                 if ((entry = snd_info_create_module_entry(THIS_MODULE, "oss", NULL)) == NULL)
 556                         return -ENOMEM;
 557                 entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
 558                 if (snd_info_register(entry) < 0) {
 559                         snd_info_free_entry(entry);
 560                         return -ENOMEM;
 561                 }
 562                 snd_oss_root = entry;
 563         }
 564 #endif
 565 #if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
 566         {
 567                 struct snd_info_entry *entry;
 568                 if ((entry = snd_info_create_module_entry(THIS_MODULE, "seq", NULL)) == NULL)
 569                         return -ENOMEM;
 570                 entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
 571                 if (snd_info_register(entry) < 0) {
 572                         snd_info_free_entry(entry);
 573                         return -ENOMEM;
 574                 }
 575                 snd_seq_root = entry;
 576         }
 577 #endif
 578         snd_info_version_init();
 579         snd_minor_info_init();
 580         snd_minor_info_oss_init();
 581         snd_card_info_init();
 582         return 0;
 583 }
 584
 585 int __exit snd_info_done(void)
 586 {
 587         snd_card_info_done();
 588         snd_minor_info_oss_done();
 589         snd_minor_info_done();
 590         snd_info_version_done();
 591         if (snd_proc_root) {
 592 #if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
 593                 snd_info_free_entry(snd_seq_root);
 594 #endif
 595 #ifdef CONFIG_SND_OSSEMUL
 596                 snd_info_free_entry(snd_oss_root);
 597 #endif
 598                 snd_remove_proc_entry(&proc_root, snd_proc_root);
 599         }
 600         return 0;
 601 }
 602
 603 /*
 604
 605  */
 606
 607
 608 /*
 609  * create a card proc file
 610  * called from init.c
 611  */
 612 int snd_info_card_create(struct snd_card *card)
 613 {
 614         char str[8];
 615         struct snd_info_entry *entry;
 616
 617         snd_assert(card != NULL, return -ENXIO);
 618
 619         sprintf(str, "card%i", card->number);
 620         if ((entry = snd_info_create_module_entry(card->module, str, NULL)) == NULL)
 621                 return -ENOMEM;
 622         entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
 623         if (snd_info_register(entry) < 0) {
 624                 snd_info_free_entry(entry);
 625                 return -ENOMEM;
 626         }
 627         card->proc_root = entry;
 628         return 0;
 629 }
 630
 631 /*
 632  * register the card proc file
 633  * called from init.c
 634  */
 635 int snd_info_card_register(struct snd_card *card)
 636 {
 637         struct proc_dir_entry *p;
 638
 639         snd_assert(card != NULL, return -ENXIO);
 640
 641         if (!strcmp(card->id, card->proc_root->name))
 642                 return 0;
 643
 644         p = proc_symlink(card->id, snd_proc_root, card->proc_root->name);
 645         if (p == NULL)
 646                 return -ENOMEM;
 647         card->proc_root_link = p;
 648         return 0;
 649 }
 650
 651 /*
 652  * de-register the card proc file
 653  * called from init.c
 654  */
 655 void snd_info_card_disconnect(struct snd_card *card)
 656 {
 657         snd_assert(card != NULL, return);
 658         mutex_lock(&info_mutex);
 659         if (card->proc_root_link) {
 660                 snd_remove_proc_entry(snd_proc_root, card->proc_root_link);
 661                 card->proc_root_link = NULL;
 662         }
 663         if (card->proc_root)
 664                 snd_info_disconnect(card->proc_root);
 665         mutex_unlock(&info_mutex);
 666 }
 667
 668 /*
 669  * release the card proc file resources
 670  * called from init.c
 671  */
 672 int snd_info_card_free(struct snd_card *card)
 673 {
 674         snd_assert(card != NULL, return -ENXIO);
 675         snd_info_free_entry(card->proc_root);
 676         card->proc_root = NULL;
 677         return 0;
 678 }
 679
 680
 681 /**
 682  * snd_info_get_line - read one line from the procfs buffer
 683  * @buffer: the procfs buffer
 684  * @line: the buffer to store
 685  * @len: the max. buffer size - 1
 686  *
 687  * Reads one line from the buffer and stores the string.
 688  *
 689  * Returns zero if successful, or 1 if error or EOF.
 690  */
 691 int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
 692 {
 693         int c = -1;
 694
 695         if (len <= 0 || buffer->stop || buffer->error)
 696                 return 1;
 697         while (--len > 0) {
 698                 c = buffer->buffer[buffer->curr++];
 699                 if (c == '\n') {
 700                         if (buffer->curr >= buffer->size)
 701                                 buffer->stop = 1;
 702                         break;
 703                 }
 704                 *line++ = c;
 705                 if (buffer->curr >= buffer->size) {
 706                         buffer->stop = 1;
 707                         break;
 708                 }
 709         }
 710         while (c != '\n' && !buffer->stop) {
 711                 c = buffer->buffer[buffer->curr++];
 712                 if (buffer->curr >= buffer->size)
 713                         buffer->stop = 1;
 714         }
 715         *line = '\0';
 716         return 0;
 717 }
 718
 719 EXPORT_SYMBOL(snd_info_get_line);
 720
 721 /**
 722  * snd_info_get_str - parse a string token
 723  * @dest: the buffer to store the string token
 724  * @src: the original string
 725  * @len: the max. length of token - 1
 726  *
 727  * Parses the original string and copy a token to the given
 728  * string buffer.
 729  *
 730  * Returns the updated pointer of the original string so that
 731  * it can be used for the next call.
 732  */
 733 char *snd_info_get_str(char *dest, char *src, int len)
 734 {
 735         int c;
 736
 737         while (*src == ' ' || *src == '\t')
 738                 src++;
 739         if (*src == '"' || *src == '\'') {
 740                 c = *src++;
 741                 while (--len > 0 && *src && *src != c) {
 742                         *dest++ = *src++;
 743                 }
 744                 if (*src == c)
 745                         src++;
 746         } else {
 747                 while (--len > 0 && *src && *src != ' ' && *src != '\t') {
 748                         *dest++ = *src++;
 749                 }
 750         }
 751         *dest = 0;
 752         while (*src == ' ' || *src == '\t')
 753                 src++;
 754         return src;
 755 }
 756
 757 EXPORT_SYMBOL(snd_info_get_str);
 758
 759 /**
 760  * snd_info_create_entry - create an info entry
 761  * @name: the proc file name
 762  *
 763  * Creates an info entry with the given file name and initializes as
 764  * the default state.
 765  *
 766  * Usually called from other functions such as
 767  * snd_info_create_card_entry().
 768  *
 769  * Returns the pointer of the new instance, or NULL on failure.
 770  */
 771 static struct snd_info_entry *snd_info_create_entry(const char *name)
 772 {
 773         struct snd_info_entry *entry;
 774         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 775         if (entry == NULL)
 776                 return NULL;
 777         entry->name = kstrdup(name, GFP_KERNEL);
 778         if (entry->name == NULL) {
 779                 kfree(entry);
 780                 return NULL;
 781         }
 782         entry->mode = S_IFREG | S_IRUGO;
 783         entry->content = SNDRV_INFO_CONTENT_TEXT;
 784         mutex_init(&entry->access);
 785         INIT_LIST_HEAD(&entry->children);
 786         INIT_LIST_HEAD(&entry->list);
 787         return entry;
 788 }
 789
 790 /**
 791  * snd_info_create_module_entry - create an info entry for the given module
 792  * @module: the module pointer
 793  * @name: the file name
 794  * @parent: the parent directory
 795  *
 796  * Creates a new info entry and assigns it to the given module.
 797  *
 798  * Returns the pointer of the new instance, or NULL on failure.
 799  */
 800 struct snd_info_entry *snd_info_create_module_entry(struct module * module,
 801                                                const char *name,
 802                                                struct snd_info_entry *parent)
 803 {
 804         struct snd_info_entry *entry = snd_info_create_entry(name);
 805         if (entry) {
 806                 entry->module = module;
 807                 entry->parent = parent;
 808         }
 809         return entry;
 810 }
 811
 812 EXPORT_SYMBOL(snd_info_create_module_entry);
 813
 814 /**
 815  * snd_info_create_card_entry - create an info entry for the given card
 816  * @card: the card instance
 817  * @name: the file name
 818  * @parent: the parent directory
 819  *
 820  * Creates a new info entry and assigns it to the given card.
 821  *
 822  * Returns the pointer of the new instance, or NULL on failure.
 823  */
 824 struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
 825                                              const char *name,
 826                                              struct snd_info_entry * parent)
 827 {
 828         struct snd_info_entry *entry = snd_info_create_entry(name);
 829         if (entry) {
 830                 entry->module = card->module;
 831                 entry->card = card;
 832                 entry->parent = parent;
 833         }
 834         return entry;
 835 }
 836
 837 EXPORT_SYMBOL(snd_info_create_card_entry);
 838
 839 static void snd_info_disconnect(struct snd_info_entry *entry)
 840 {
 841         struct list_head *p, *n;
 842         struct proc_dir_entry *root;
 843
 844         list_for_each_safe(p, n, &entry->children) {
 845                 snd_info_disconnect(list_entry(p, struct snd_info_entry, list));
 846         }
 847
 848         if (! entry->p)
 849                 return;
 850         list_del_init(&entry->list);
 851         root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
 852         snd_assert(root, return);
 853         snd_remove_proc_entry(root, entry->p);
 854         entry->p = NULL;
 855 }
 856
 857 static int snd_info_dev_free_entry(struct snd_device *device)
 858 {
 859         struct snd_info_entry *entry = device->device_data;
 860         snd_info_free_entry(entry);
 861         return 0;
 862 }
 863
 864 static int snd_info_dev_register_entry(struct snd_device *device)
 865 {
 866         struct snd_info_entry *entry = device->device_data;
 867         return snd_info_register(entry);
 868 }
 869
 870 /**
 871  * snd_card_proc_new - create an info entry for the given card
 872  * @card: the card instance
 873  * @name: the file name
 874  * @entryp: the pointer to store the new info entry
 875  *
 876  * Creates a new info entry and assigns it to the given card.
 877  * Unlike snd_info_create_card_entry(), this function registers the
 878  * info entry as an ALSA device component, so that it can be
 879  * unregistered/released without explicit call.
 880  * Also, you don't have to register this entry via snd_info_register(),
 881  * since this will be registered by snd_card_register() automatically.
 882  *
 883  * The parent is assumed as card->proc_root.
 884  *
 885  * For releasing this entry, use snd_device_free() instead of
 886  * snd_info_free_entry().
 887  *
 888  * Returns zero if successful, or a negative error code on failure.
 889  */
 890 int snd_card_proc_new(struct snd_card *card, const char *name,
 891                       struct snd_info_entry **entryp)
 892 {
 893         static struct snd_device_ops ops = {
 894                 .dev_free = snd_info_dev_free_entry,
 895                 .dev_register = snd_info_dev_register_entry,
 896                 /* disconnect is done via snd_info_card_disconnect() */
 897         };
 898         struct snd_info_entry *entry;
 899         int err;
 900
 901         entry = snd_info_create_card_entry(card, name, card->proc_root);
 902         if (! entry)
 903                 return -ENOMEM;
 904         if ((err = snd_device_new(card, SNDRV_DEV_INFO, entry, &ops)) < 0) {
 905                 snd_info_free_entry(entry);
 906                 return err;
 907         }
 908         if (entryp)
 909                 *entryp = entry;
 910         return 0;
 911 }
 912
 913 EXPORT_SYMBOL(snd_card_proc_new);
 914
 915 /**
 916  * snd_info_free_entry - release the info entry
 917  * @entry: the info entry
 918  *
 919  * Releases the info entry.  Don't call this after registered.
 920  */
 921 void snd_info_free_entry(struct snd_info_entry * entry)
 922 {
 923         if (entry == NULL)
 924                 return;
 925         if (entry->p) {
 926                 mutex_lock(&info_mutex);
 927                 snd_info_disconnect(entry);
 928                 mutex_unlock(&info_mutex);
 929         }
 930         kfree(entry->name);
 931         if (entry->private_free)
 932                 entry->private_free(entry);
 933         kfree(entry);
 934 }
 935
 936 EXPORT_SYMBOL(snd_info_free_entry);
 937
 938 /**
 939  * snd_info_register - register the info entry
 940  * @entry: the info entry
 941  *
 942  * Registers the proc info entry.
 943  *
 944  * Returns zero if successful, or a negative error code on failure.
 945  */
 946 int snd_info_register(struct snd_info_entry * entry)
 947 {
 948         struct proc_dir_entry *root, *p = NULL;
 949
 950         snd_assert(entry != NULL, return -ENXIO);
 951         root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
 952         mutex_lock(&info_mutex);
 953         p = snd_create_proc_entry(entry->name, entry->mode, root);
 954         if (!p) {
 955                 mutex_unlock(&info_mutex);
 956                 return -ENOMEM;
 957         }
 958         p->owner = entry->module;
 959         if (!S_ISDIR(entry->mode))
 960                 p->proc_fops = &snd_info_entry_operations;
 961         p->size = entry->size;
 962         p->data = entry;
 963         entry->p = p;
 964         if (entry->parent)
 965                 list_add_tail(&entry->list, &entry->parent->children);
 966         mutex_unlock(&info_mutex);
 967         return 0;
 968 }
 969
 970 EXPORT_SYMBOL(snd_info_register);
 971
 972 /*
 973
 974  */
 975
 976 static struct snd_info_entry *snd_info_version_entry;
 977
 978 static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 979 {
 980         snd_iprintf(buffer,
 981                     "Advanced Linux Sound Architecture Driver Version "
 982                     CONFIG_SND_VERSION CONFIG_SND_DATE ".\n"
 983                    );
 984 }
 985
 986 static int __init snd_info_version_init(void)
 987 {
 988         struct snd_info_entry *entry;
 989
 990         entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
 991         if (entry == NULL)
 992                 return -ENOMEM;
 993         entry->c.text.read = snd_info_version_read;
 994         if (snd_info_register(entry) < 0) {
 995                 snd_info_free_entry(entry);
 996                 return -ENOMEM;
 997         }
 998         snd_info_version_entry = entry;
 999         return 0;
1000 }
1001
1002 static int __exit snd_info_version_done(void)
1003 {
1004         snd_info_free_entry(snd_info_version_entry);
1005         return 0;
1006 }
1007
1008 #endif /* CONFIG_PROC_FS */