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 <sound/version.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 /* resize the proc r/w buffer */
  86 static int resize_info_buffer(struct snd_info_buffer *buffer,
  87                               unsigned int nsize)
  88 {
  89         char *nbuf;
  90
  91         nsize = PAGE_ALIGN(nsize);
  92         nbuf = krealloc(buffer->buffer, nsize, GFP_KERNEL);
  93         if (! nbuf)
  94                 return -ENOMEM;
  95
  96         buffer->buffer = nbuf;
  97         buffer->len = nsize;
  98         return 0;
  99 }
 100
 101 /**
 102  * snd_iprintf - printf on the procfs buffer
 103  * @buffer: the procfs buffer
 104  * @fmt: the printf format
 105  *
 106  * Outputs the string on the procfs buffer just like printf().
 107  *
 108  * Returns the size of output string.
 109  */
 110 int snd_iprintf(struct snd_info_buffer *buffer, const char *fmt, ...)
 111 {
 112         va_list args;
 113         int len, res;
 114         int err = 0;
 115
 116         might_sleep();
 117         if (buffer->stop || buffer->error)
 118                 return 0;
 119         len = buffer->len - buffer->size;
 120         va_start(args, fmt);
 121         for (;;) {
 122                 va_list ap;
 123                 va_copy(ap, args);
 124                 res = vsnprintf(buffer->buffer + buffer->curr, len, fmt, ap);
 125                 va_end(ap);
 126                 if (res < len)
 127                         break;
 128                 err = resize_info_buffer(buffer, buffer->len + PAGE_SIZE);
 129                 if (err < 0)
 130                         break;
 131                 len = buffer->len - buffer->size;
 132         }
 133         va_end(args);
 134
 135         if (err < 0)
 136                 return err;
 137         buffer->curr += res;
 138         buffer->size += res;
 139         return res;
 140 }
 141
 142 EXPORT_SYMBOL(snd_iprintf);
 143
 144 /*
 145
 146  */
 147
 148 static struct proc_dir_entry *snd_proc_root;
 149 struct snd_info_entry *snd_seq_root;
 150 EXPORT_SYMBOL(snd_seq_root);
 151
 152 #ifdef CONFIG_SND_OSSEMUL
 153 struct snd_info_entry *snd_oss_root;
 154 #endif
 155
 156 static void snd_remove_proc_entry(struct proc_dir_entry *parent,
 157                                   struct proc_dir_entry *de)
 158 {
 159         if (de)
 160                 remove_proc_entry(de->name, parent);
 161 }
 162
 163 static loff_t snd_info_entry_llseek(struct file *file, loff_t offset, int orig)
 164 {
 165         struct snd_info_private_data *data;
 166         struct snd_info_entry *entry;
 167         loff_t ret = -EINVAL, size;
 168
 169         data = file->private_data;
 170         entry = data->entry;
 171         mutex_lock(&entry->access);
 172         if (entry->content == SNDRV_INFO_CONTENT_DATA &&
 173             entry->c.ops->llseek) {
 174                 offset = entry->c.ops->llseek(entry,
 175                                               data->file_private_data,
 176                                               file, offset, orig);
 177                 goto out;
 178         }
 179         if (entry->content == SNDRV_INFO_CONTENT_DATA)
 180                 size = entry->size;
 181         else
 182                 size = 0;
 183         switch (orig) {
 184         case SEEK_SET:
 185                 break;
 186         case SEEK_CUR:
 187                 offset += file->f_pos;
 188                 break;
 189         case SEEK_END:
 190                 if (!size)
 191                         goto out;
 192                 offset += size;
 193                 break;
 194         default:
 195                 goto out;
 196         }
 197         if (offset < 0)
 198                 goto out;
 199         if (size && offset > size)
 200                 offset = size;
 201         file->f_pos = offset;
 202         ret = offset;
 203  out:
 204         mutex_unlock(&entry->access);
 205         return ret;
 206 }
 207
 208 static ssize_t snd_info_entry_read(struct file *file, char __user *buffer,
 209                                    size_t count, loff_t * offset)
 210 {
 211         struct snd_info_private_data *data;
 212         struct snd_info_entry *entry;
 213         struct snd_info_buffer *buf;
 214         size_t size = 0;
 215         loff_t pos;
 216
 217         data = file->private_data;
 218         if (snd_BUG_ON(!data))
 219                 return -ENXIO;
 220         pos = *offset;
 221         if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
 222                 return -EIO;
 223         if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
 224                 return -EIO;
 225         entry = data->entry;
 226         switch (entry->content) {
 227         case SNDRV_INFO_CONTENT_TEXT:
 228                 buf = data->rbuffer;
 229                 if (buf == NULL)
 230                         return -EIO;
 231                 if (pos >= buf->size)
 232                         return 0;
 233                 size = buf->size - pos;
 234                 size = min(count, size);
 235                 if (copy_to_user(buffer, buf->buffer + pos, size))
 236                         return -EFAULT;
 237                 break;
 238         case SNDRV_INFO_CONTENT_DATA:
 239                 if (pos >= entry->size)
 240                         return 0;
 241                 if (entry->c.ops->read) {
 242                         size = entry->size - pos;
 243                         size = min(count, size);
 244                         size = entry->c.ops->read(entry,
 245                                                   data->file_private_data,
 246                                                   file, buffer, size, pos);
 247                 }
 248                 break;
 249         }
 250         if ((ssize_t) size > 0)
 251                 *offset = pos + size;
 252         return size;
 253 }
 254
 255 static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer,
 256                                     size_t count, loff_t * offset)
 257 {
 258         struct snd_info_private_data *data;
 259         struct snd_info_entry *entry;
 260         struct snd_info_buffer *buf;
 261         ssize_t size = 0;
 262         loff_t pos;
 263
 264         data = file->private_data;
 265         if (snd_BUG_ON(!data))
 266                 return -ENXIO;
 267         entry = data->entry;
 268         pos = *offset;
 269         if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
 270                 return -EIO;
 271         if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
 272                 return -EIO;
 273         switch (entry->content) {
 274         case SNDRV_INFO_CONTENT_TEXT:
 275                 buf = data->wbuffer;
 276                 if (buf == NULL)
 277                         return -EIO;
 278                 mutex_lock(&entry->access);
 279                 if (pos + count >= buf->len) {
 280                         if (resize_info_buffer(buf, pos + count)) {
 281                                 mutex_unlock(&entry->access);
 282                                 return -ENOMEM;
 283                         }
 284                 }
 285                 if (copy_from_user(buf->buffer + pos, buffer, count)) {
 286                         mutex_unlock(&entry->access);
 287                         return -EFAULT;
 288                 }
 289                 buf->size = pos + count;
 290                 mutex_unlock(&entry->access);
 291                 size = count;
 292                 break;
 293         case SNDRV_INFO_CONTENT_DATA:
 294                 if (entry->c.ops->write && count > 0) {
 295                         size_t maxsize = entry->size - pos;
 296                         count = min(count, maxsize);
 297                         size = entry->c.ops->write(entry,
 298                                                    data->file_private_data,
 299                                                    file, buffer, count, pos);
 300                 }
 301                 break;
 302         }
 303         if ((ssize_t) size > 0)
 304                 *offset = pos + size;
 305         return size;
 306 }
 307
 308 static int snd_info_entry_open(struct inode *inode, struct file *file)
 309 {
 310         struct snd_info_entry *entry;
 311         struct snd_info_private_data *data;
 312         struct snd_info_buffer *buffer;
 313         struct proc_dir_entry *p;
 314         int mode, err;
 315
 316         mutex_lock(&info_mutex);
 317         p = PDE(inode);
 318         entry = p == NULL ? NULL : (struct snd_info_entry *)p->data;
 319         if (entry == NULL || ! entry->p) {
 320                 mutex_unlock(&info_mutex);
 321                 return -ENODEV;
 322         }
 323         if (!try_module_get(entry->module)) {
 324                 err = -EFAULT;
 325                 goto __error1;
 326         }
 327         mode = file->f_flags & O_ACCMODE;
 328         if (mode == O_RDONLY || mode == O_RDWR) {
 329                 if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
 330                      entry->c.ops->read == NULL)) {
 331                         err = -ENODEV;
 332                         goto __error;
 333                 }
 334         }
 335         if (mode == O_WRONLY || mode == O_RDWR) {
 336                 if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
 337                      entry->c.ops->write == NULL)) {
 338                         err = -ENODEV;
 339                         goto __error;
 340                 }
 341         }
 342         data = kzalloc(sizeof(*data), GFP_KERNEL);
 343         if (data == NULL) {
 344                 err = -ENOMEM;
 345                 goto __error;
 346         }
 347         data->entry = entry;
 348         switch (entry->content) {
 349         case SNDRV_INFO_CONTENT_TEXT:
 350                 if (mode == O_RDONLY || mode == O_RDWR) {
 351                         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 352                         if (buffer == NULL)
 353                                 goto __nomem;
 354                         data->rbuffer = buffer;
 355                         buffer->len = PAGE_SIZE;
 356                         buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
 357                         if (buffer->buffer == NULL)
 358                                 goto __nomem;
 359                 }
 360                 if (mode == O_WRONLY || mode == O_RDWR) {
 361                         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 362                         if (buffer == NULL)
 363                                 goto __nomem;
 364                         data->wbuffer = buffer;
 365                         buffer->len = PAGE_SIZE;
 366                         buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
 367                         if (buffer->buffer == NULL)
 368                                 goto __nomem;
 369                 }
 370                 break;
 371         case SNDRV_INFO_CONTENT_DATA:   /* data */
 372                 if (entry->c.ops->open) {
 373                         if ((err = entry->c.ops->open(entry, mode,
 374                                                       &data->file_private_data)) < 0) {
 375                                 kfree(data);
 376                                 goto __error;
 377                         }
 378                 }
 379                 break;
 380         }
 381         file->private_data = data;
 382         mutex_unlock(&info_mutex);
 383         if (entry->content == SNDRV_INFO_CONTENT_TEXT &&
 384             (mode == O_RDONLY || mode == O_RDWR)) {
 385                 if (entry->c.text.read) {
 386                         mutex_lock(&entry->access);
 387                         entry->c.text.read(entry, data->rbuffer);
 388                         mutex_unlock(&entry->access);
 389                 }
 390         }
 391         return 0;
 392
 393  __nomem:
 394         if (data->rbuffer) {
 395                 kfree(data->rbuffer->buffer);
 396                 kfree(data->rbuffer);
 397         }
 398         if (data->wbuffer) {
 399                 kfree(data->wbuffer->buffer);
 400                 kfree(data->wbuffer);
 401         }
 402         kfree(data);
 403         err = -ENOMEM;
 404       __error:
 405         module_put(entry->module);
 406       __error1:
 407         mutex_unlock(&info_mutex);
 408         return err;
 409 }
 410
 411 static int snd_info_entry_release(struct inode *inode, struct file *file)
 412 {
 413         struct snd_info_entry *entry;
 414         struct snd_info_private_data *data;
 415         int mode;
 416
 417         mode = file->f_flags & O_ACCMODE;
 418         data = file->private_data;
 419         entry = data->entry;
 420         switch (entry->content) {
 421         case SNDRV_INFO_CONTENT_TEXT:
 422                 if (data->rbuffer) {
 423                         kfree(data->rbuffer->buffer);
 424                         kfree(data->rbuffer);
 425                 }
 426                 if (data->wbuffer) {
 427                         if (entry->c.text.write) {
 428                                 entry->c.text.write(entry, data->wbuffer);
 429                                 if (data->wbuffer->error) {
 430                                         snd_printk(KERN_WARNING "data write error to %s (%i)\n",
 431                                                 entry->name,
 432                                                 data->wbuffer->error);
 433                                 }
 434                         }
 435                         kfree(data->wbuffer->buffer);
 436                         kfree(data->wbuffer);
 437                 }
 438                 break;
 439         case SNDRV_INFO_CONTENT_DATA:
 440                 if (entry->c.ops->release)
 441                         entry->c.ops->release(entry, mode,
 442                                               data->file_private_data);
 443                 break;
 444         }
 445         module_put(entry->module);
 446         kfree(data);
 447         return 0;
 448 }
 449
 450 static unsigned int snd_info_entry_poll(struct file *file, poll_table * wait)
 451 {
 452         struct snd_info_private_data *data;
 453         struct snd_info_entry *entry;
 454         unsigned int mask;
 455
 456         data = file->private_data;
 457         if (data == NULL)
 458                 return 0;
 459         entry = data->entry;
 460         mask = 0;
 461         switch (entry->content) {
 462         case SNDRV_INFO_CONTENT_DATA:
 463                 if (entry->c.ops->poll)
 464                         return entry->c.ops->poll(entry,
 465                                                   data->file_private_data,
 466                                                   file, wait);
 467                 if (entry->c.ops->read)
 468                         mask |= POLLIN | POLLRDNORM;
 469                 if (entry->c.ops->write)
 470                         mask |= POLLOUT | POLLWRNORM;
 471                 break;
 472         }
 473         return mask;
 474 }
 475
 476 static long snd_info_entry_ioctl(struct file *file, unsigned int cmd,
 477                                 unsigned long arg)
 478 {
 479         struct snd_info_private_data *data;
 480         struct snd_info_entry *entry;
 481
 482         data = file->private_data;
 483         if (data == NULL)
 484                 return 0;
 485         entry = data->entry;
 486         switch (entry->content) {
 487         case SNDRV_INFO_CONTENT_DATA:
 488                 if (entry->c.ops->ioctl)
 489                         return entry->c.ops->ioctl(entry,
 490                                                    data->file_private_data,
 491                                                    file, cmd, arg);
 492                 break;
 493         }
 494         return -ENOTTY;
 495 }
 496
 497 static int snd_info_entry_mmap(struct file *file, struct vm_area_struct *vma)
 498 {
 499         struct inode *inode = file->f_path.dentry->d_inode;
 500         struct snd_info_private_data *data;
 501         struct snd_info_entry *entry;
 502
 503         data = file->private_data;
 504         if (data == NULL)
 505                 return 0;
 506         entry = data->entry;
 507         switch (entry->content) {
 508         case SNDRV_INFO_CONTENT_DATA:
 509                 if (entry->c.ops->mmap)
 510                         return entry->c.ops->mmap(entry,
 511                                                   data->file_private_data,
 512                                                   inode, file, vma);
 513                 break;
 514         }
 515         return -ENXIO;
 516 }
 517
 518 static const struct file_operations snd_info_entry_operations =
 519 {
 520         .owner =                THIS_MODULE,
 521         .llseek =               snd_info_entry_llseek,
 522         .read =                 snd_info_entry_read,
 523         .write =                snd_info_entry_write,
 524         .poll =                 snd_info_entry_poll,
 525         .unlocked_ioctl =       snd_info_entry_ioctl,
 526         .mmap =                 snd_info_entry_mmap,
 527         .open =                 snd_info_entry_open,
 528         .release =              snd_info_entry_release,
 529 };
 530
 531 int __init snd_info_init(void)
 532 {
 533         struct proc_dir_entry *p;
 534
 535         p = proc_mkdir("asound", NULL);
 536         if (p == NULL)
 537                 return -ENOMEM;
 538         snd_proc_root = p;
 539 #ifdef CONFIG_SND_OSSEMUL
 540         {
 541                 struct snd_info_entry *entry;
 542                 if ((entry = snd_info_create_module_entry(THIS_MODULE, "oss", NULL)) == NULL)
 543                         return -ENOMEM;
 544                 entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
 545                 if (snd_info_register(entry) < 0) {
 546                         snd_info_free_entry(entry);
 547                         return -ENOMEM;
 548                 }
 549                 snd_oss_root = entry;
 550         }
 551 #endif
 552 #if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
 553         {
 554                 struct snd_info_entry *entry;
 555                 if ((entry = snd_info_create_module_entry(THIS_MODULE, "seq", 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_seq_root = entry;
 563         }
 564 #endif
 565         snd_info_version_init();
 566         snd_minor_info_init();
 567         snd_minor_info_oss_init();
 568         snd_card_info_init();
 569         return 0;
 570 }
 571
 572 int __exit snd_info_done(void)
 573 {
 574         snd_card_info_done();
 575         snd_minor_info_oss_done();
 576         snd_minor_info_done();
 577         snd_info_version_done();
 578         if (snd_proc_root) {
 579 #if defined(CONFIG_SND_SEQUENCER) || defined(CONFIG_SND_SEQUENCER_MODULE)
 580                 snd_info_free_entry(snd_seq_root);
 581 #endif
 582 #ifdef CONFIG_SND_OSSEMUL
 583                 snd_info_free_entry(snd_oss_root);
 584 #endif
 585                 snd_remove_proc_entry(NULL, snd_proc_root);
 586         }
 587         return 0;
 588 }
 589
 590 /*
 591
 592  */
 593
 594
 595 /*
 596  * create a card proc file
 597  * called from init.c
 598  */
 599 int snd_info_card_create(struct snd_card *card)
 600 {
 601         char str[8];
 602         struct snd_info_entry *entry;
 603
 604         if (snd_BUG_ON(!card))
 605                 return -ENXIO;
 606
 607         sprintf(str, "card%i", card->number);
 608         if ((entry = snd_info_create_module_entry(card->module, str, NULL)) == NULL)
 609                 return -ENOMEM;
 610         entry->mode = S_IFDIR | S_IRUGO | S_IXUGO;
 611         if (snd_info_register(entry) < 0) {
 612                 snd_info_free_entry(entry);
 613                 return -ENOMEM;
 614         }
 615         card->proc_root = entry;
 616         return 0;
 617 }
 618
 619 /*
 620  * register the card proc file
 621  * called from init.c
 622  */
 623 int snd_info_card_register(struct snd_card *card)
 624 {
 625         struct proc_dir_entry *p;
 626
 627         if (snd_BUG_ON(!card))
 628                 return -ENXIO;
 629
 630         if (!strcmp(card->id, card->proc_root->name))
 631                 return 0;
 632
 633         p = proc_symlink(card->id, snd_proc_root, card->proc_root->name);
 634         if (p == NULL)
 635                 return -ENOMEM;
 636         card->proc_root_link = p;
 637         return 0;
 638 }
 639
 640 /*
 641  * called on card->id change
 642  */
 643 void snd_info_card_id_change(struct snd_card *card)
 644 {
 645         mutex_lock(&info_mutex);
 646         if (card->proc_root_link) {
 647                 snd_remove_proc_entry(snd_proc_root, card->proc_root_link);
 648                 card->proc_root_link = NULL;
 649         }
 650         if (strcmp(card->id, card->proc_root->name))
 651                 card->proc_root_link = proc_symlink(card->id,
 652                                                     snd_proc_root,
 653                                                     card->proc_root->name);
 654         mutex_unlock(&info_mutex);
 655 }
 656
 657 /*
 658  * de-register the card proc file
 659  * called from init.c
 660  */
 661 void snd_info_card_disconnect(struct snd_card *card)
 662 {
 663         if (!card)
 664                 return;
 665         mutex_lock(&info_mutex);
 666         if (card->proc_root_link) {
 667                 snd_remove_proc_entry(snd_proc_root, card->proc_root_link);
 668                 card->proc_root_link = NULL;
 669         }
 670         if (card->proc_root)
 671                 snd_info_disconnect(card->proc_root);
 672         mutex_unlock(&info_mutex);
 673 }
 674
 675 /*
 676  * release the card proc file resources
 677  * called from init.c
 678  */
 679 int snd_info_card_free(struct snd_card *card)
 680 {
 681         if (!card)
 682                 return 0;
 683         snd_info_free_entry(card->proc_root);
 684         card->proc_root = NULL;
 685         return 0;
 686 }
 687
 688
 689 /**
 690  * snd_info_get_line - read one line from the procfs buffer
 691  * @buffer: the procfs buffer
 692  * @line: the buffer to store
 693  * @len: the max. buffer size - 1
 694  *
 695  * Reads one line from the buffer and stores the string.
 696  *
 697  * Returns zero if successful, or 1 if error or EOF.
 698  */
 699 int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
 700 {
 701         int c = -1;
 702
 703         if (len <= 0 || buffer->stop || buffer->error)
 704                 return 1;
 705         while (--len > 0) {
 706                 c = buffer->buffer[buffer->curr++];
 707                 if (c == '\n') {
 708                         if (buffer->curr >= buffer->size)
 709                                 buffer->stop = 1;
 710                         break;
 711                 }
 712                 *line++ = c;
 713                 if (buffer->curr >= buffer->size) {
 714                         buffer->stop = 1;
 715                         break;
 716                 }
 717         }
 718         while (c != '\n' && !buffer->stop) {
 719                 c = buffer->buffer[buffer->curr++];
 720                 if (buffer->curr >= buffer->size)
 721                         buffer->stop = 1;
 722         }
 723         *line = '\0';
 724         return 0;
 725 }
 726
 727 EXPORT_SYMBOL(snd_info_get_line);
 728
 729 /**
 730  * snd_info_get_str - parse a string token
 731  * @dest: the buffer to store the string token
 732  * @src: the original string
 733  * @len: the max. length of token - 1
 734  *
 735  * Parses the original string and copy a token to the given
 736  * string buffer.
 737  *
 738  * Returns the updated pointer of the original string so that
 739  * it can be used for the next call.
 740  */
 741 const char *snd_info_get_str(char *dest, const char *src, int len)
 742 {
 743         int c;
 744
 745         while (*src == ' ' || *src == '\t')
 746                 src++;
 747         if (*src == '"' || *src == '\'') {
 748                 c = *src++;
 749                 while (--len > 0 && *src && *src != c) {
 750                         *dest++ = *src++;
 751                 }
 752                 if (*src == c)
 753                         src++;
 754         } else {
 755                 while (--len > 0 && *src && *src != ' ' && *src != '\t') {
 756                         *dest++ = *src++;
 757                 }
 758         }
 759         *dest = 0;
 760         while (*src == ' ' || *src == '\t')
 761                 src++;
 762         return src;
 763 }
 764
 765 EXPORT_SYMBOL(snd_info_get_str);
 766
 767 /**
 768  * snd_info_create_entry - create an info entry
 769  * @name: the proc file name
 770  *
 771  * Creates an info entry with the given file name and initializes as
 772  * the default state.
 773  *
 774  * Usually called from other functions such as
 775  * snd_info_create_card_entry().
 776  *
 777  * Returns the pointer of the new instance, or NULL on failure.
 778  */
 779 static struct snd_info_entry *snd_info_create_entry(const char *name)
 780 {
 781         struct snd_info_entry *entry;
 782         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 783         if (entry == NULL)
 784                 return NULL;
 785         entry->name = kstrdup(name, GFP_KERNEL);
 786         if (entry->name == NULL) {
 787                 kfree(entry);
 788                 return NULL;
 789         }
 790         entry->mode = S_IFREG | S_IRUGO;
 791         entry->content = SNDRV_INFO_CONTENT_TEXT;
 792         mutex_init(&entry->access);
 793         INIT_LIST_HEAD(&entry->children);
 794         INIT_LIST_HEAD(&entry->list);
 795         return entry;
 796 }
 797
 798 /**
 799  * snd_info_create_module_entry - create an info entry for the given module
 800  * @module: the module pointer
 801  * @name: the file name
 802  * @parent: the parent directory
 803  *
 804  * Creates a new info entry and assigns it to the given module.
 805  *
 806  * Returns the pointer of the new instance, or NULL on failure.
 807  */
 808 struct snd_info_entry *snd_info_create_module_entry(struct module * module,
 809                                                const char *name,
 810                                                struct snd_info_entry *parent)
 811 {
 812         struct snd_info_entry *entry = snd_info_create_entry(name);
 813         if (entry) {
 814                 entry->module = module;
 815                 entry->parent = parent;
 816         }
 817         return entry;
 818 }
 819
 820 EXPORT_SYMBOL(snd_info_create_module_entry);
 821
 822 /**
 823  * snd_info_create_card_entry - create an info entry for the given card
 824  * @card: the card instance
 825  * @name: the file name
 826  * @parent: the parent directory
 827  *
 828  * Creates a new info entry and assigns it to the given card.
 829  *
 830  * Returns the pointer of the new instance, or NULL on failure.
 831  */
 832 struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
 833                                              const char *name,
 834                                              struct snd_info_entry * parent)
 835 {
 836         struct snd_info_entry *entry = snd_info_create_entry(name);
 837         if (entry) {
 838                 entry->module = card->module;
 839                 entry->card = card;
 840                 entry->parent = parent;
 841         }
 842         return entry;
 843 }
 844
 845 EXPORT_SYMBOL(snd_info_create_card_entry);
 846
 847 static void snd_info_disconnect(struct snd_info_entry *entry)
 848 {
 849         struct list_head *p, *n;
 850         struct proc_dir_entry *root;
 851
 852         list_for_each_safe(p, n, &entry->children) {
 853                 snd_info_disconnect(list_entry(p, struct snd_info_entry, list));
 854         }
 855
 856         if (! entry->p)
 857                 return;
 858         list_del_init(&entry->list);
 859         root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
 860         snd_BUG_ON(!root);
 861         snd_remove_proc_entry(root, entry->p);
 862         entry->p = NULL;
 863 }
 864
 865 static int snd_info_dev_free_entry(struct snd_device *device)
 866 {
 867         struct snd_info_entry *entry = device->device_data;
 868         snd_info_free_entry(entry);
 869         return 0;
 870 }
 871
 872 static int snd_info_dev_register_entry(struct snd_device *device)
 873 {
 874         struct snd_info_entry *entry = device->device_data;
 875         return snd_info_register(entry);
 876 }
 877
 878 /**
 879  * snd_card_proc_new - create an info entry for the given card
 880  * @card: the card instance
 881  * @name: the file name
 882  * @entryp: the pointer to store the new info entry
 883  *
 884  * Creates a new info entry and assigns it to the given card.
 885  * Unlike snd_info_create_card_entry(), this function registers the
 886  * info entry as an ALSA device component, so that it can be
 887  * unregistered/released without explicit call.
 888  * Also, you don't have to register this entry via snd_info_register(),
 889  * since this will be registered by snd_card_register() automatically.
 890  *
 891  * The parent is assumed as card->proc_root.
 892  *
 893  * For releasing this entry, use snd_device_free() instead of
 894  * snd_info_free_entry().
 895  *
 896  * Returns zero if successful, or a negative error code on failure.
 897  */
 898 int snd_card_proc_new(struct snd_card *card, const char *name,
 899                       struct snd_info_entry **entryp)
 900 {
 901         static struct snd_device_ops ops = {
 902                 .dev_free = snd_info_dev_free_entry,
 903                 .dev_register = snd_info_dev_register_entry,
 904                 /* disconnect is done via snd_info_card_disconnect() */
 905         };
 906         struct snd_info_entry *entry;
 907         int err;
 908
 909         entry = snd_info_create_card_entry(card, name, card->proc_root);
 910         if (! entry)
 911                 return -ENOMEM;
 912         if ((err = snd_device_new(card, SNDRV_DEV_INFO, entry, &ops)) < 0) {
 913                 snd_info_free_entry(entry);
 914                 return err;
 915         }
 916         if (entryp)
 917                 *entryp = entry;
 918         return 0;
 919 }
 920
 921 EXPORT_SYMBOL(snd_card_proc_new);
 922
 923 /**
 924  * snd_info_free_entry - release the info entry
 925  * @entry: the info entry
 926  *
 927  * Releases the info entry.  Don't call this after registered.
 928  */
 929 void snd_info_free_entry(struct snd_info_entry * entry)
 930 {
 931         if (entry == NULL)
 932                 return;
 933         if (entry->p) {
 934                 mutex_lock(&info_mutex);
 935                 snd_info_disconnect(entry);
 936                 mutex_unlock(&info_mutex);
 937         }
 938         kfree(entry->name);
 939         if (entry->private_free)
 940                 entry->private_free(entry);
 941         kfree(entry);
 942 }
 943
 944 EXPORT_SYMBOL(snd_info_free_entry);
 945
 946 /**
 947  * snd_info_register - register the info entry
 948  * @entry: the info entry
 949  *
 950  * Registers the proc info entry.
 951  *
 952  * Returns zero if successful, or a negative error code on failure.
 953  */
 954 int snd_info_register(struct snd_info_entry * entry)
 955 {
 956         struct proc_dir_entry *root, *p = NULL;
 957
 958         if (snd_BUG_ON(!entry))
 959                 return -ENXIO;
 960         root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
 961         mutex_lock(&info_mutex);
 962         p = create_proc_entry(entry->name, entry->mode, root);
 963         if (!p) {
 964                 mutex_unlock(&info_mutex);
 965                 return -ENOMEM;
 966         }
 967         if (!S_ISDIR(entry->mode))
 968                 p->proc_fops = &snd_info_entry_operations;
 969         p->size = entry->size;
 970         p->data = entry;
 971         entry->p = p;
 972         if (entry->parent)
 973                 list_add_tail(&entry->list, &entry->parent->children);
 974         mutex_unlock(&info_mutex);
 975         return 0;
 976 }
 977
 978 EXPORT_SYMBOL(snd_info_register);
 979
 980 /*
 981
 982  */
 983
 984 static struct snd_info_entry *snd_info_version_entry;
 985
 986 static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 987 {
 988         snd_iprintf(buffer,
 989                     "Advanced Linux Sound Architecture Driver Version "
 990                     CONFIG_SND_VERSION CONFIG_SND_DATE ".\n"
 991                    );
 992 }
 993
 994 static int __init snd_info_version_init(void)
 995 {
 996         struct snd_info_entry *entry;
 997
 998         entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
 999         if (entry == NULL)
1000                 return -ENOMEM;
1001         entry->c.text.read = snd_info_version_read;
1002         if (snd_info_register(entry) < 0) {
1003                 snd_info_free_entry(entry);
1004                 return -ENOMEM;
1005         }
1006         snd_info_version_entry = entry;
1007         return 0;
1008 }
1009
1010 static int __exit snd_info_version_done(void)
1011 {
1012         snd_info_free_entry(snd_info_version_entry);
1013         return 0;
1014 }
1015
1016 #endif /* CONFIG_PROC_FS */