sound/core/info.c

   1 /*
   2  *  Information interface for ALSA driver
   3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   4  *
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19  *
  20  */
  21
  22 #include <linux/init.h>
  23 #include <linux/time.h>
  24 #include <linux/mm.h>
  25 #include <linux/slab.h>
  26 #include <linux/string.h>
  27 #include <linux/module.h>
  28 #include <sound/core.h>
  29 #include <sound/minors.h>
  30 #include <sound/info.h>
  31 #include <linux/utsname.h>
  32 #include <linux/proc_fs.h>
  33 #include <linux/mutex.h>
  34 #include <stdarg.h>
  35
  36 /*
  37  *
  38  */
  39
  40 #ifdef CONFIG_PROC_FS
  41
  42 int snd_info_check_reserved_words(const char *str)
  43 {
  44         static char *reserved[] =
  45         {
  46                 "version",
  47                 "meminfo",
  48                 "memdebug",
  49                 "detect",
  50                 "devices",
  51                 "oss",
  52                 "cards",
  53                 "timers",
  54                 "synth",
  55                 "pcm",
  56                 "seq",
  57                 NULL
  58         };
  59         char **xstr = reserved;
  60
  61         while (*xstr) {
  62                 if (!strcmp(*xstr, str))
  63                         return 0;
  64                 xstr++;
  65         }
  66         if (!strncmp(str, "card", 4))
  67                 return 0;
  68         return 1;
  69 }
  70
  71 static DEFINE_MUTEX(info_mutex);
  72
  73 struct snd_info_private_data {
  74         struct snd_info_buffer *rbuffer;
  75         struct snd_info_buffer *wbuffer;
  76         struct snd_info_entry *entry;
  77         void *file_private_data;
  78 };
  79
  80 static int snd_info_version_init(void);
  81 static int snd_info_version_done(void);
  82 static void snd_info_disconnect(struct snd_info_entry *entry);
  83
  84
  85 /* 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 | __GFP_ZERO);
  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  * Return: The size of output string, or a negative error code.
 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 = kzalloc(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_inode(file);
 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  * Return: 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 (snd_BUG_ON(!buffer || !buffer->buffer))
 704                 return 1;
 705         if (len <= 0 || buffer->stop || buffer->error)
 706                 return 1;
 707         while (!buffer->stop) {
 708                 c = buffer->buffer[buffer->curr++];
 709                 if (buffer->curr >= buffer->size)
 710                         buffer->stop = 1;
 711                 if (c == '\n')
 712                         break;
 713                 if (len) {
 714                         len--;
 715                         *line++ = c;
 716                 }
 717         }
 718         *line = '\0';
 719         return 0;
 720 }
 721
 722 EXPORT_SYMBOL(snd_info_get_line);
 723
 724 /**
 725  * snd_info_get_str - parse a string token
 726  * @dest: the buffer to store the string token
 727  * @src: the original string
 728  * @len: the max. length of token - 1
 729  *
 730  * Parses the original string and copy a token to the given
 731  * string buffer.
 732  *
 733  * Return: The updated pointer of the original string so that
 734  * it can be used for the next call.
 735  */
 736 const char *snd_info_get_str(char *dest, const char *src, int len)
 737 {
 738         int c;
 739
 740         while (*src == ' ' || *src == '\t')
 741                 src++;
 742         if (*src == '"' || *src == '\'') {
 743                 c = *src++;
 744                 while (--len > 0 && *src && *src != c) {
 745                         *dest++ = *src++;
 746                 }
 747                 if (*src == c)
 748                         src++;
 749         } else {
 750                 while (--len > 0 && *src && *src != ' ' && *src != '\t') {
 751                         *dest++ = *src++;
 752                 }
 753         }
 754         *dest = 0;
 755         while (*src == ' ' || *src == '\t')
 756                 src++;
 757         return src;
 758 }
 759
 760 EXPORT_SYMBOL(snd_info_get_str);
 761
 762 /**
 763  * snd_info_create_entry - create an info entry
 764  * @name: the proc file name
 765  *
 766  * Creates an info entry with the given file name and initializes as
 767  * the default state.
 768  *
 769  * Usually called from other functions such as
 770  * snd_info_create_card_entry().
 771  *
 772  * Return: The pointer of the new instance, or %NULL on failure.
 773  */
 774 static struct snd_info_entry *snd_info_create_entry(const char *name)
 775 {
 776         struct snd_info_entry *entry;
 777         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 778         if (entry == NULL)
 779                 return NULL;
 780         entry->name = kstrdup(name, GFP_KERNEL);
 781         if (entry->name == NULL) {
 782                 kfree(entry);
 783                 return NULL;
 784         }
 785         entry->mode = S_IFREG | S_IRUGO;
 786         entry->content = SNDRV_INFO_CONTENT_TEXT;
 787         mutex_init(&entry->access);
 788         INIT_LIST_HEAD(&entry->children);
 789         INIT_LIST_HEAD(&entry->list);
 790         return entry;
 791 }
 792
 793 /**
 794  * snd_info_create_module_entry - create an info entry for the given module
 795  * @module: the module pointer
 796  * @name: the file name
 797  * @parent: the parent directory
 798  *
 799  * Creates a new info entry and assigns it to the given module.
 800  *
 801  * Return: The pointer of the new instance, or %NULL on failure.
 802  */
 803 struct snd_info_entry *snd_info_create_module_entry(struct module * module,
 804                                                const char *name,
 805                                                struct snd_info_entry *parent)
 806 {
 807         struct snd_info_entry *entry = snd_info_create_entry(name);
 808         if (entry) {
 809                 entry->module = module;
 810                 entry->parent = parent;
 811         }
 812         return entry;
 813 }
 814
 815 EXPORT_SYMBOL(snd_info_create_module_entry);
 816
 817 /**
 818  * snd_info_create_card_entry - create an info entry for the given card
 819  * @card: the card instance
 820  * @name: the file name
 821  * @parent: the parent directory
 822  *
 823  * Creates a new info entry and assigns it to the given card.
 824  *
 825  * Return: The pointer of the new instance, or %NULL on failure.
 826  */
 827 struct snd_info_entry *snd_info_create_card_entry(struct snd_card *card,
 828                                              const char *name,
 829                                              struct snd_info_entry * parent)
 830 {
 831         struct snd_info_entry *entry = snd_info_create_entry(name);
 832         if (entry) {
 833                 entry->module = card->module;
 834                 entry->card = card;
 835                 entry->parent = parent;
 836         }
 837         return entry;
 838 }
 839
 840 EXPORT_SYMBOL(snd_info_create_card_entry);
 841
 842 static void snd_info_disconnect(struct snd_info_entry *entry)
 843 {
 844         struct list_head *p, *n;
 845         struct proc_dir_entry *root;
 846
 847         list_for_each_safe(p, n, &entry->children) {
 848                 snd_info_disconnect(list_entry(p, struct snd_info_entry, list));
 849         }
 850
 851         if (! entry->p)
 852                 return;
 853         list_del_init(&entry->list);
 854         root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
 855         snd_BUG_ON(!root);
 856         snd_remove_proc_entry(root, entry->p);
 857         entry->p = NULL;
 858 }
 859
 860 static int snd_info_dev_free_entry(struct snd_device *device)
 861 {
 862         struct snd_info_entry *entry = device->device_data;
 863         snd_info_free_entry(entry);
 864         return 0;
 865 }
 866
 867 static int snd_info_dev_register_entry(struct snd_device *device)
 868 {
 869         struct snd_info_entry *entry = device->device_data;
 870         return snd_info_register(entry);
 871 }
 872
 873 /**
 874  * snd_card_proc_new - create an info entry for the given card
 875  * @card: the card instance
 876  * @name: the file name
 877  * @entryp: the pointer to store the new info entry
 878  *
 879  * Creates a new info entry and assigns it to the given card.
 880  * Unlike snd_info_create_card_entry(), this function registers the
 881  * info entry as an ALSA device component, so that it can be
 882  * unregistered/released without explicit call.
 883  * Also, you don't have to register this entry via snd_info_register(),
 884  * since this will be registered by snd_card_register() automatically.
 885  *
 886  * The parent is assumed as card->proc_root.
 887  *
 888  * For releasing this entry, use snd_device_free() instead of
 889  * snd_info_free_entry().
 890  *
 891  * Return: Zero if successful, or a negative error code on failure.
 892  */
 893 int snd_card_proc_new(struct snd_card *card, const char *name,
 894                       struct snd_info_entry **entryp)
 895 {
 896         static struct snd_device_ops ops = {
 897                 .dev_free = snd_info_dev_free_entry,
 898                 .dev_register = snd_info_dev_register_entry,
 899                 /* disconnect is done via snd_info_card_disconnect() */
 900         };
 901         struct snd_info_entry *entry;
 902         int err;
 903
 904         entry = snd_info_create_card_entry(card, name, card->proc_root);
 905         if (! entry)
 906                 return -ENOMEM;
 907         if ((err = snd_device_new(card, SNDRV_DEV_INFO, entry, &ops)) < 0) {
 908                 snd_info_free_entry(entry);
 909                 return err;
 910         }
 911         if (entryp)
 912                 *entryp = entry;
 913         return 0;
 914 }
 915
 916 EXPORT_SYMBOL(snd_card_proc_new);
 917
 918 /**
 919  * snd_info_free_entry - release the info entry
 920  * @entry: the info entry
 921  *
 922  * Releases the info entry.  Don't call this after registered.
 923  */
 924 void snd_info_free_entry(struct snd_info_entry * entry)
 925 {
 926         if (entry == NULL)
 927                 return;
 928         if (entry->p) {
 929                 mutex_lock(&info_mutex);
 930                 snd_info_disconnect(entry);
 931                 mutex_unlock(&info_mutex);
 932         }
 933         kfree(entry->name);
 934         if (entry->private_free)
 935                 entry->private_free(entry);
 936         kfree(entry);
 937 }
 938
 939 EXPORT_SYMBOL(snd_info_free_entry);
 940
 941 /**
 942  * snd_info_register - register the info entry
 943  * @entry: the info entry
 944  *
 945  * Registers the proc info entry.
 946  *
 947  * Return: Zero if successful, or a negative error code on failure.
 948  */
 949 int snd_info_register(struct snd_info_entry * entry)
 950 {
 951         struct proc_dir_entry *root, *p = NULL;
 952
 953         if (snd_BUG_ON(!entry))
 954                 return -ENXIO;
 955         root = entry->parent == NULL ? snd_proc_root : entry->parent->p;
 956         mutex_lock(&info_mutex);
 957         p = create_proc_entry(entry->name, entry->mode, root);
 958         if (!p) {
 959                 mutex_unlock(&info_mutex);
 960                 return -ENOMEM;
 961         }
 962         if (!S_ISDIR(entry->mode))
 963                 p->proc_fops = &snd_info_entry_operations;
 964         p->size = entry->size;
 965         p->data = entry;
 966         entry->p = p;
 967         if (entry->parent)
 968                 list_add_tail(&entry->list, &entry->parent->children);
 969         mutex_unlock(&info_mutex);
 970         return 0;
 971 }
 972
 973 EXPORT_SYMBOL(snd_info_register);
 974
 975 /*
 976
 977  */
 978
 979 static struct snd_info_entry *snd_info_version_entry;
 980
 981 static void snd_info_version_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
 982 {
 983         snd_iprintf(buffer,
 984                     "Advanced Linux Sound Architecture Driver Version k%s.\n",
 985                     init_utsname()->release);
 986 }
 987
 988 static int __init snd_info_version_init(void)
 989 {
 990         struct snd_info_entry *entry;
 991
 992         entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
 993         if (entry == NULL)
 994                 return -ENOMEM;
 995         entry->c.text.read = snd_info_version_read;
 996         if (snd_info_register(entry) < 0) {
 997                 snd_info_free_entry(entry);
 998                 return -ENOMEM;
 999         }
1000         snd_info_version_entry = entry;
1001         return 0;
1002 }
1003
1004 static int __exit snd_info_version_done(void)
1005 {
1006         snd_info_free_entry(snd_info_version_entry);
1007         return 0;
1008 }
1009
1010 #endif /* CONFIG_PROC_FS */