kern/disk.c

   1 /*
   2  *  GRUB  --  GRand Unified Bootloader
   3  *  Copyright (C) 2002,2003,2004,2006,2007,2008  Free Software Foundation, Inc.
   4  *
   5  *  GRUB is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation, either version 3 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  GRUB is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <grub/disk.h>
  20 #include <grub/err.h>
  21 #include <grub/mm.h>
  22 #include <grub/types.h>
  23 #include <grub/partition.h>
  24 #include <grub/misc.h>
  25 #include <grub/time.h>
  26 #include <grub/file.h>
  27
  28 #define GRUB_CACHE_TIMEOUT      2
  29
  30 /* The last time the disk was used.  */
  31 static grub_uint64_t grub_last_time = 0;
  32
  33
  34 /* Disk cache.  */
  35 struct grub_disk_cache
  36 {
  37   enum grub_disk_dev_id dev_id;
  38   unsigned long disk_id;
  39   grub_disk_addr_t sector;
  40   char *data;
  41   int lock;
  42 };
  43
  44 static struct grub_disk_cache grub_disk_cache_table[GRUB_DISK_CACHE_NUM];
  45
  46 void (*grub_disk_firmware_fini) (void);
  47 int grub_disk_firmware_is_tainted;
  48
  49 grub_err_t (* grub_disk_ata_pass_through) (grub_disk_t,
  50             struct grub_disk_ata_pass_through_parms *);
  51
  52
  53 #if 0
  54 static unsigned long grub_disk_cache_hits;
  55 static unsigned long grub_disk_cache_misses;
  56
  57 void
  58 grub_disk_cache_get_performance (unsigned long *hits, unsigned long *misses)
  59 {
  60   *hits = grub_disk_cache_hits;
  61   *misses = grub_disk_cache_misses;
  62 }
  63 #endif
  64
  65 static unsigned
  66 grub_disk_cache_get_index (unsigned long dev_id, unsigned long disk_id,
  67                            grub_disk_addr_t sector)
  68 {
  69   return ((dev_id * 524287UL + disk_id * 2606459UL
  70            + ((unsigned) (sector >> GRUB_DISK_CACHE_BITS)))
  71           % GRUB_DISK_CACHE_NUM);
  72 }
  73
  74 static void
  75 grub_disk_cache_invalidate (unsigned long dev_id, unsigned long disk_id,
  76                             grub_disk_addr_t sector)
  77 {
  78   unsigned index;
  79   struct grub_disk_cache *cache;
  80
  81   sector &= ~(GRUB_DISK_CACHE_SIZE - 1);
  82   index = grub_disk_cache_get_index (dev_id, disk_id, sector);
  83   cache = grub_disk_cache_table + index;
  84
  85   if (cache->dev_id == dev_id && cache->disk_id == disk_id
  86       && cache->sector == sector && cache->data)
  87     {
  88       cache->lock = 1;
  89       grub_free (cache->data);
  90       cache->data = 0;
  91       cache->lock = 0;
  92     }
  93 }
  94
  95 void
  96 grub_disk_cache_invalidate_all (void)
  97 {
  98   unsigned i;
  99
 100   for (i = 0; i < GRUB_DISK_CACHE_NUM; i++)
 101     {
 102       struct grub_disk_cache *cache = grub_disk_cache_table + i;
 103
 104       if (cache->data && ! cache->lock)
 105         {
 106           grub_free (cache->data);
 107           cache->data = 0;
 108         }
 109     }
 110 }
 111
 112 static char *
 113 grub_disk_cache_fetch (unsigned long dev_id, unsigned long disk_id,
 114                        grub_disk_addr_t sector)
 115 {
 116   struct grub_disk_cache *cache;
 117   unsigned index;
 118
 119   index = grub_disk_cache_get_index (dev_id, disk_id, sector);
 120   cache = grub_disk_cache_table + index;
 121
 122   if (cache->dev_id == dev_id && cache->disk_id == disk_id
 123       && cache->sector == sector)
 124     {
 125       cache->lock = 1;
 126 #if 0
 127       grub_disk_cache_hits++;
 128 #endif
 129       return cache->data;
 130     }
 131
 132 #if 0
 133   grub_disk_cache_misses++;
 134 #endif
 135
 136   return 0;
 137 }
 138
 139 static void
 140 grub_disk_cache_unlock (unsigned long dev_id, unsigned long disk_id,
 141                         grub_disk_addr_t sector)
 142 {
 143   struct grub_disk_cache *cache;
 144   unsigned index;
 145
 146   index = grub_disk_cache_get_index (dev_id, disk_id, sector);
 147   cache = grub_disk_cache_table + index;
 148
 149   if (cache->dev_id == dev_id && cache->disk_id == disk_id
 150       && cache->sector == sector)
 151     cache->lock = 0;
 152 }
 153
 154 static grub_err_t
 155 grub_disk_cache_store (unsigned long dev_id, unsigned long disk_id,
 156                        grub_disk_addr_t sector, const char *data)
 157 {
 158   unsigned index;
 159   struct grub_disk_cache *cache;
 160
 161   index = grub_disk_cache_get_index (dev_id, disk_id, sector);
 162   cache = grub_disk_cache_table + index;
 163
 164   cache->lock = 1;
 165   grub_free (cache->data);
 166   cache->data = 0;
 167   cache->lock = 0;
 168
 169   cache->data = grub_malloc (GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS);
 170   if (! cache->data)
 171     return grub_errno;
 172
 173   grub_memcpy (cache->data, data,
 174                GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS);
 175   cache->dev_id = dev_id;
 176   cache->disk_id = disk_id;
 177   cache->sector = sector;
 178
 179   return GRUB_ERR_NONE;
 180 }
 181
 182 \f
 183
 184 static grub_disk_dev_t grub_disk_dev_list;
 185
 186 void
 187 grub_disk_dev_register (grub_disk_dev_t dev)
 188 {
 189   dev->next = grub_disk_dev_list;
 190   grub_disk_dev_list = dev;
 191 }
 192
 193 void
 194 grub_disk_dev_unregister (grub_disk_dev_t dev)
 195 {
 196   grub_disk_dev_t *p, q;
 197
 198   for (p = &grub_disk_dev_list, q = *p; q; p = &(q->next), q = q->next)
 199     if (q == dev)
 200       {
 201         *p = q->next;
 202         break;
 203       }
 204 }
 205
 206 int
 207 grub_disk_dev_iterate (int (*hook) (const char *name))
 208 {
 209   grub_disk_dev_t p;
 210
 211   for (p = grub_disk_dev_list; p; p = p->next)
 212     if (p->iterate && (p->iterate) (hook))
 213       return 1;
 214
 215   return 0;
 216 }
 217
 218 /* Return the location of the first ',', if any, which is not
 219    escaped by a '\'.  */
 220 static const char *
 221 find_part_sep (const char *name)
 222 {
 223   const char *p = name;
 224   char c;
 225
 226   while ((c = *p++) != '\0')
 227     {
 228       if (c == '\\' && *p == ',')
 229         p++;
 230       else if (c == ',')
 231         return p - 1;
 232     }
 233   return NULL;
 234 }
 235
 236 grub_disk_t
 237 grub_disk_open (const char *name)
 238 {
 239   const char *p;
 240   grub_disk_t disk;
 241   grub_disk_dev_t dev;
 242   char *raw = (char *) name;
 243   grub_uint64_t current_time;
 244
 245   grub_dprintf ("disk", "Opening `%s'...\n", name);
 246
 247   disk = (grub_disk_t) grub_zalloc (sizeof (*disk));
 248   if (! disk)
 249     return 0;
 250
 251   disk->name = grub_strdup (name);
 252   if (! disk->name)
 253     goto fail;
 254
 255   p = find_part_sep (name);
 256   if (p)
 257     {
 258       grub_size_t len = p - name;
 259
 260       raw = grub_malloc (len + 1);
 261       if (! raw)
 262         goto fail;
 263
 264       grub_memcpy (raw, name, len);
 265       raw[len] = '\0';
 266     }
 267
 268   for (dev = grub_disk_dev_list; dev; dev = dev->next)
 269     {
 270       if ((dev->open) (raw, disk) == GRUB_ERR_NONE)
 271         break;
 272       else if (grub_errno == GRUB_ERR_UNKNOWN_DEVICE)
 273         grub_errno = GRUB_ERR_NONE;
 274       else
 275         goto fail;
 276     }
 277
 278   if (! dev)
 279     {
 280       grub_error (GRUB_ERR_UNKNOWN_DEVICE, "no such disk");
 281       goto fail;
 282     }
 283
 284   if (p && ! disk->has_partitions)
 285     {
 286       grub_error (GRUB_ERR_BAD_DEVICE, "no partition on this disk");
 287       goto fail;
 288     }
 289
 290   disk->dev = dev;
 291
 292   if (p)
 293     {
 294       disk->partition = grub_partition_probe (disk, p + 1);
 295       if (! disk->partition)
 296         {
 297           grub_error (GRUB_ERR_UNKNOWN_DEVICE, "no such partition");
 298           goto fail;
 299         }
 300     }
 301
 302   /* The cache will be invalidated about 2 seconds after a device was
 303      closed.  */
 304   current_time = grub_get_time_ms ();
 305
 306   if (current_time > (grub_last_time
 307                       + GRUB_CACHE_TIMEOUT * 1000))
 308     grub_disk_cache_invalidate_all ();
 309
 310   grub_last_time = current_time;
 311
 312  fail:
 313
 314   if (raw && raw != name)
 315     grub_free (raw);
 316
 317   if (grub_errno != GRUB_ERR_NONE)
 318     {
 319       grub_error_push ();
 320       grub_dprintf ("disk", "Opening `%s' failed.\n", name);
 321       grub_error_pop ();
 322
 323       grub_disk_close (disk);
 324       return 0;
 325     }
 326
 327   return disk;
 328 }
 329
 330 void
 331 grub_disk_close (grub_disk_t disk)
 332 {
 333   grub_dprintf ("disk", "Closing `%s'.\n", disk->name);
 334
 335   if (disk->dev && disk->dev->close)
 336     (disk->dev->close) (disk);
 337
 338   /* Reset the timer.  */
 339   grub_last_time = grub_get_time_ms ();
 340
 341   grub_free (disk->partition);
 342   grub_free ((void *) disk->name);
 343   grub_free (disk);
 344 }
 345
 346 /* This function performs three tasks:
 347    - Make sectors disk relative from partition relative.
 348    - Normalize offset to be less than the sector size.
 349    - Verify that the range is inside the partition.  */
 350 static grub_err_t
 351 grub_disk_adjust_range (grub_disk_t disk, grub_disk_addr_t *sector,
 352                        grub_off_t *offset, grub_size_t size)
 353 {
 354   *sector += *offset >> GRUB_DISK_SECTOR_BITS;
 355   *offset &= GRUB_DISK_SECTOR_SIZE - 1;
 356
 357   if (disk->partition)
 358     {
 359       grub_disk_addr_t start;
 360       grub_uint64_t len;
 361
 362       start = grub_partition_get_start (disk->partition);
 363       len = grub_partition_get_len (disk->partition);
 364
 365       if (*sector >= len
 366           || len - *sector < ((*offset + size + GRUB_DISK_SECTOR_SIZE - 1)
 367                               >> GRUB_DISK_SECTOR_BITS))
 368         return grub_error (GRUB_ERR_OUT_OF_RANGE, "out of partition");
 369
 370       *sector += start;
 371     }
 372
 373   if (disk->total_sectors <= *sector
 374       || ((*offset + size + GRUB_DISK_SECTOR_SIZE - 1)
 375           >> GRUB_DISK_SECTOR_BITS) > disk->total_sectors - *sector)
 376     return grub_error (GRUB_ERR_OUT_OF_RANGE, "out of disk");
 377
 378   return GRUB_ERR_NONE;
 379 }
 380
 381 /* Read data from the disk.  */
 382 grub_err_t
 383 grub_disk_read (grub_disk_t disk, grub_disk_addr_t sector,
 384                 grub_off_t offset, grub_size_t size, void *buf)
 385 {
 386   char *tmp_buf;
 387   unsigned real_offset;
 388
 389   grub_dprintf ("disk", "Reading `%s'...\n", disk->name);
 390
 391   /* First of all, check if the region is within the disk.  */
 392   if (grub_disk_adjust_range (disk, &sector, &offset, size) != GRUB_ERR_NONE)
 393     {
 394       grub_error_push ();
 395       grub_dprintf ("disk", "Read out of range: sector 0x%llx (%s).\n",
 396                     (unsigned long long) sector, grub_errmsg);
 397       grub_error_pop ();
 398       return grub_errno;
 399     }
 400
 401   real_offset = offset;
 402
 403   /* Allocate a temporary buffer.  */
 404   tmp_buf = grub_malloc (GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS);
 405   if (! tmp_buf)
 406     return grub_errno;
 407
 408   /* Until SIZE is zero...  */
 409   while (size)
 410     {
 411       char *data;
 412       grub_disk_addr_t start_sector;
 413       grub_size_t len;
 414       grub_size_t pos;
 415
 416       /* For reading bulk data.  */
 417       start_sector = sector & ~(GRUB_DISK_CACHE_SIZE - 1);
 418       pos = (sector - start_sector) << GRUB_DISK_SECTOR_BITS;
 419       len = ((GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS)
 420              - pos - real_offset);
 421       if (len > size)
 422         len = size;
 423
 424       /* Fetch the cache.  */
 425       data = grub_disk_cache_fetch (disk->dev->id, disk->id, start_sector);
 426       if (data)
 427         {
 428           /* Just copy it!  */
 429           grub_memcpy (buf, data + pos + real_offset, len);
 430           grub_disk_cache_unlock (disk->dev->id, disk->id, start_sector);
 431         }
 432       else
 433         {
 434           /* Otherwise read data from the disk actually.  */
 435           if ((disk->dev->read) (disk, start_sector,
 436                                  GRUB_DISK_CACHE_SIZE, tmp_buf)
 437               != GRUB_ERR_NONE)
 438             {
 439               /* Uggh... Failed. Instead, just read necessary data.  */
 440               unsigned num;
 441               char *p;
 442
 443               grub_errno = GRUB_ERR_NONE;
 444
 445               num = ((size + GRUB_DISK_SECTOR_SIZE - 1)
 446                      >> GRUB_DISK_SECTOR_BITS);
 447
 448               p = grub_realloc (tmp_buf, num << GRUB_DISK_SECTOR_BITS);
 449               if (!p)
 450                 goto finish;
 451
 452               tmp_buf = p;
 453
 454               if ((disk->dev->read) (disk, sector, num, tmp_buf))
 455                 {
 456                   grub_error_push ();
 457                   grub_dprintf ("disk", "%s read failed\n", disk->name);
 458                   grub_error_pop ();
 459                   goto finish;
 460                 }
 461
 462               grub_memcpy (buf, tmp_buf + real_offset, size);
 463
 464               /* Call the read hook, if any.  */
 465               if (disk->read_hook)
 466                 while (size)
 467                   {
 468                     (disk->read_hook) (sector, real_offset,
 469                                        ((size > GRUB_DISK_SECTOR_SIZE)
 470                                         ? GRUB_DISK_SECTOR_SIZE
 471                                         : size));
 472                     sector++;
 473                     size -= GRUB_DISK_SECTOR_SIZE - real_offset;
 474                     real_offset = 0;
 475                   }
 476
 477               /* This must be the end.  */
 478               goto finish;
 479             }
 480
 481           /* Copy it and store it in the disk cache.  */
 482           grub_memcpy (buf, tmp_buf + pos + real_offset, len);
 483           grub_disk_cache_store (disk->dev->id, disk->id,
 484                                  start_sector, tmp_buf);
 485         }
 486
 487       /* Call the read hook, if any.  */
 488       if (disk->read_hook)
 489         {
 490           grub_disk_addr_t s = sector;
 491           grub_size_t l = len;
 492
 493           while (l)
 494             {
 495               (disk->read_hook) (s, real_offset,
 496                                  ((l > GRUB_DISK_SECTOR_SIZE)
 497                                   ? GRUB_DISK_SECTOR_SIZE
 498                                   : l));
 499
 500               if (l < GRUB_DISK_SECTOR_SIZE - real_offset)
 501                 break;
 502
 503               s++;
 504               l -= GRUB_DISK_SECTOR_SIZE - real_offset;
 505               real_offset = 0;
 506             }
 507         }
 508
 509       sector = start_sector + GRUB_DISK_CACHE_SIZE;
 510       buf = (char *) buf + len;
 511       size -= len;
 512       real_offset = 0;
 513     }
 514
 515  finish:
 516
 517   grub_free (tmp_buf);
 518
 519   return grub_errno;
 520 }
 521
 522 grub_err_t
 523 grub_disk_write (grub_disk_t disk, grub_disk_addr_t sector,
 524                  grub_off_t offset, grub_size_t size, const void *buf)
 525 {
 526   unsigned real_offset;
 527
 528   grub_dprintf ("disk", "Writing `%s'...\n", disk->name);
 529
 530   if (grub_disk_adjust_range (disk, &sector, &offset, size) != GRUB_ERR_NONE)
 531     return -1;
 532
 533   real_offset = offset;
 534
 535   while (size)
 536     {
 537       if (real_offset != 0 || (size < GRUB_DISK_SECTOR_SIZE && size != 0))
 538         {
 539           char tmp_buf[GRUB_DISK_SECTOR_SIZE];
 540           grub_size_t len;
 541           grub_partition_t part;
 542
 543           part = disk->partition;
 544           disk->partition = 0;
 545           if (grub_disk_read (disk, sector, 0, GRUB_DISK_SECTOR_SIZE, tmp_buf)
 546               != GRUB_ERR_NONE)
 547             {
 548               disk->partition = part;
 549               goto finish;
 550             }
 551           disk->partition = part;
 552
 553           len = GRUB_DISK_SECTOR_SIZE - real_offset;
 554           if (len > size)
 555             len = size;
 556
 557           grub_memcpy (tmp_buf + real_offset, buf, len);
 558
 559           grub_disk_cache_invalidate (disk->dev->id, disk->id, sector);
 560
 561           if ((disk->dev->write) (disk, sector, 1, tmp_buf) != GRUB_ERR_NONE)
 562             goto finish;
 563
 564           sector++;
 565           buf = (char *) buf + len;
 566           size -= len;
 567           real_offset = 0;
 568         }
 569       else
 570         {
 571           grub_size_t len;
 572           grub_size_t n;
 573
 574           len = size & ~(GRUB_DISK_SECTOR_SIZE - 1);
 575           n = size >> GRUB_DISK_SECTOR_BITS;
 576
 577           if ((disk->dev->write) (disk, sector, n, buf) != GRUB_ERR_NONE)
 578             goto finish;
 579
 580           while (n--)
 581             grub_disk_cache_invalidate (disk->dev->id, disk->id, sector++);
 582
 583           buf = (char *) buf + len;
 584           size -= len;
 585         }
 586     }
 587
 588  finish:
 589
 590   return grub_errno;
 591 }
 592
 593 grub_uint64_t
 594 grub_disk_get_size (grub_disk_t disk)
 595 {
 596   if (disk->partition)
 597     return grub_partition_get_len (disk->partition);
 598   else
 599     return disk->total_sectors;
 600 }