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   unsigned long 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_malloc (sizeof (*disk));
 248   if (! disk)
 249     return 0;
 250
 251   disk->dev = 0;
 252   disk->read_hook = 0;
 253   disk->partition = 0;
 254   disk->data = 0;
 255   disk->name = grub_strdup (name);
 256   if (! disk->name)
 257     goto fail;
 258
 259   p = find_part_sep (name);
 260   if (p)
 261     {
 262       grub_size_t len = p - name;
 263
 264       raw = grub_malloc (len + 1);
 265       if (! raw)
 266         goto fail;
 267
 268       grub_memcpy (raw, name, len);
 269       raw[len] = '\0';
 270     }
 271
 272   for (dev = grub_disk_dev_list; dev; dev = dev->next)
 273     {
 274       if ((dev->open) (raw, disk) == GRUB_ERR_NONE)
 275         break;
 276       else if (grub_errno == GRUB_ERR_UNKNOWN_DEVICE)
 277         grub_errno = GRUB_ERR_NONE;
 278       else
 279         goto fail;
 280     }
 281
 282   if (! dev)
 283     {
 284       grub_error (GRUB_ERR_UNKNOWN_DEVICE, "no such disk");
 285       goto fail;
 286     }
 287
 288   if (p && ! disk->has_partitions)
 289     {
 290       grub_error (GRUB_ERR_BAD_DEVICE, "no partition on this disk");
 291       goto fail;
 292     }
 293
 294   disk->dev = dev;
 295
 296   if (p)
 297     {
 298       disk->partition = grub_partition_probe (disk, p + 1);
 299       if (! disk->partition)
 300         {
 301           grub_error (GRUB_ERR_UNKNOWN_DEVICE, "no such partition");
 302           goto fail;
 303         }
 304     }
 305
 306   /* The cache will be invalidated about 2 seconds after a device was
 307      closed.  */
 308   current_time = grub_get_time_ms ();
 309
 310   if (current_time > (grub_last_time
 311                       + GRUB_CACHE_TIMEOUT * 1000))
 312     grub_disk_cache_invalidate_all ();
 313
 314   grub_last_time = current_time;
 315
 316  fail:
 317
 318   if (raw && raw != name)
 319     grub_free (raw);
 320
 321   if (grub_errno != GRUB_ERR_NONE)
 322     {
 323       grub_error_push ();
 324       grub_dprintf ("disk", "Opening `%s' failed.\n", name);
 325       grub_error_pop ();
 326
 327       grub_disk_close (disk);
 328       return 0;
 329     }
 330
 331   return disk;
 332 }
 333
 334 void
 335 grub_disk_close (grub_disk_t disk)
 336 {
 337   grub_dprintf ("disk", "Closing `%s'.\n", disk->name);
 338
 339   if (disk->dev && disk->dev->close)
 340     (disk->dev->close) (disk);
 341
 342   /* Reset the timer.  */
 343   grub_last_time = grub_get_time_ms ();
 344
 345   grub_free (disk->partition);
 346   grub_free ((void *) disk->name);
 347   grub_free (disk);
 348 }
 349
 350 /* This function performs three tasks:
 351    - Make sectors disk relative from partition relative.
 352    - Normalize offset to be less than the sector size.
 353    - Verify that the range is inside the partition.  */
 354 static grub_err_t
 355 grub_disk_adjust_range (grub_disk_t disk, grub_disk_addr_t *sector,
 356                        grub_off_t *offset, grub_size_t size)
 357 {
 358   *sector += *offset >> GRUB_DISK_SECTOR_BITS;
 359   *offset &= GRUB_DISK_SECTOR_SIZE - 1;
 360
 361   if (disk->partition)
 362     {
 363       grub_disk_addr_t start;
 364       grub_uint64_t len;
 365
 366       start = grub_partition_get_start (disk->partition);
 367       len = grub_partition_get_len (disk->partition);
 368
 369       if (*sector >= len
 370           || len - *sector < ((*offset + size + GRUB_DISK_SECTOR_SIZE - 1)
 371                               >> GRUB_DISK_SECTOR_BITS))
 372         return grub_error (GRUB_ERR_OUT_OF_RANGE, "out of partition");
 373
 374       *sector += start;
 375     }
 376
 377   if (disk->total_sectors <= *sector
 378       || ((*offset + size + GRUB_DISK_SECTOR_SIZE - 1)
 379           >> GRUB_DISK_SECTOR_BITS) > disk->total_sectors - *sector)
 380     return grub_error (GRUB_ERR_OUT_OF_RANGE, "out of disk");
 381
 382   return GRUB_ERR_NONE;
 383 }
 384
 385 /* Read data from the disk.  */
 386 grub_err_t
 387 grub_disk_read (grub_disk_t disk, grub_disk_addr_t sector,
 388                 grub_off_t offset, grub_size_t size, void *buf)
 389 {
 390   char *tmp_buf;
 391   unsigned real_offset;
 392
 393   grub_dprintf ("disk", "Reading `%s'...\n", disk->name);
 394
 395   /* First of all, check if the region is within the disk.  */
 396   if (grub_disk_adjust_range (disk, &sector, &offset, size) != GRUB_ERR_NONE)
 397     {
 398       grub_error_push ();
 399       grub_dprintf ("disk", "Read out of range: sector 0x%llx (%s).\n",
 400                     (unsigned long long) sector, grub_errmsg);
 401       grub_error_pop ();
 402       return grub_errno;
 403     }
 404
 405   real_offset = offset;
 406
 407   /* Allocate a temporary buffer.  */
 408   tmp_buf = grub_malloc (GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS);
 409   if (! tmp_buf)
 410     return grub_errno;
 411
 412   /* Until SIZE is zero...  */
 413   while (size)
 414     {
 415       char *data;
 416       grub_disk_addr_t start_sector;
 417       grub_size_t len;
 418       grub_size_t pos;
 419
 420       /* For reading bulk data.  */
 421       start_sector = sector & ~(GRUB_DISK_CACHE_SIZE - 1);
 422       pos = (sector - start_sector) << GRUB_DISK_SECTOR_BITS;
 423       len = ((GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS)
 424              - pos - real_offset);
 425       if (len > size)
 426         len = size;
 427
 428       /* Fetch the cache.  */
 429       data = grub_disk_cache_fetch (disk->dev->id, disk->id, start_sector);
 430       if (data)
 431         {
 432           /* Just copy it!  */
 433           grub_memcpy (buf, data + pos + real_offset, len);
 434           grub_disk_cache_unlock (disk->dev->id, disk->id, start_sector);
 435         }
 436       else
 437         {
 438           /* Otherwise read data from the disk actually.  */
 439           if ((disk->dev->read) (disk, start_sector,
 440                                  GRUB_DISK_CACHE_SIZE, tmp_buf)
 441               != GRUB_ERR_NONE)
 442             {
 443               /* Uggh... Failed. Instead, just read necessary data.  */
 444               unsigned num;
 445               char *p;
 446
 447               grub_errno = GRUB_ERR_NONE;
 448
 449               num = ((size + GRUB_DISK_SECTOR_SIZE - 1)
 450                      >> GRUB_DISK_SECTOR_BITS);
 451
 452               p = grub_realloc (tmp_buf, num << GRUB_DISK_SECTOR_BITS);
 453               if (!p)
 454                 goto finish;
 455
 456               tmp_buf = p;
 457
 458               if ((disk->dev->read) (disk, sector, num, tmp_buf))
 459                 {
 460                   grub_error_push ();
 461                   grub_dprintf ("disk", "%s read failed\n", disk->name);
 462                   grub_error_pop ();
 463                   goto finish;
 464                 }
 465
 466               grub_memcpy (buf, tmp_buf + real_offset, size);
 467
 468               /* Call the read hook, if any.  */
 469               if (disk->read_hook)
 470                 while (size)
 471                   {
 472                     (disk->read_hook) (sector, real_offset,
 473                                        ((size > GRUB_DISK_SECTOR_SIZE)
 474                                         ? GRUB_DISK_SECTOR_SIZE
 475                                         : size));
 476                     sector++;
 477                     size -= GRUB_DISK_SECTOR_SIZE - real_offset;
 478                     real_offset = 0;
 479                   }
 480
 481               /* This must be the end.  */
 482               goto finish;
 483             }
 484
 485           /* Copy it and store it in the disk cache.  */
 486           grub_memcpy (buf, tmp_buf + pos + real_offset, len);
 487           grub_disk_cache_store (disk->dev->id, disk->id,
 488                                  start_sector, tmp_buf);
 489         }
 490
 491       /* Call the read hook, if any.  */
 492       if (disk->read_hook)
 493         {
 494           grub_disk_addr_t s = sector;
 495           grub_size_t l = len;
 496
 497           while (l)
 498             {
 499               (disk->read_hook) (s, real_offset,
 500                                  ((l > GRUB_DISK_SECTOR_SIZE)
 501                                   ? GRUB_DISK_SECTOR_SIZE
 502                                   : l));
 503
 504               if (l < GRUB_DISK_SECTOR_SIZE - real_offset)
 505                 break;
 506
 507               s++;
 508               l -= GRUB_DISK_SECTOR_SIZE - real_offset;
 509               real_offset = 0;
 510             }
 511         }
 512
 513       sector = start_sector + GRUB_DISK_CACHE_SIZE;
 514       buf = (char *) buf + len;
 515       size -= len;
 516       real_offset = 0;
 517     }
 518
 519  finish:
 520
 521   grub_free (tmp_buf);
 522
 523   return grub_errno;
 524 }
 525
 526 grub_err_t
 527 grub_disk_write (grub_disk_t disk, grub_disk_addr_t sector,
 528                  grub_off_t offset, grub_size_t size, const void *buf)
 529 {
 530   unsigned real_offset;
 531
 532   grub_dprintf ("disk", "Writing `%s'...\n", disk->name);
 533
 534   if (grub_disk_adjust_range (disk, &sector, &offset, size) != GRUB_ERR_NONE)
 535     return -1;
 536
 537   real_offset = offset;
 538
 539   while (size)
 540     {
 541       if (real_offset != 0 || (size < GRUB_DISK_SECTOR_SIZE && size != 0))
 542         {
 543           char tmp_buf[GRUB_DISK_SECTOR_SIZE];
 544           grub_size_t len;
 545           grub_partition_t part;
 546
 547           part = disk->partition;
 548           disk->partition = 0;
 549           if (grub_disk_read (disk, sector, 0, GRUB_DISK_SECTOR_SIZE, tmp_buf)
 550               != GRUB_ERR_NONE)
 551             {
 552               disk->partition = part;
 553               goto finish;
 554             }
 555           disk->partition = part;
 556
 557           len = GRUB_DISK_SECTOR_SIZE - real_offset;
 558           if (len > size)
 559             len = size;
 560
 561           grub_memcpy (tmp_buf + real_offset, buf, len);
 562
 563           grub_disk_cache_invalidate (disk->dev->id, disk->id, sector);
 564
 565           if ((disk->dev->write) (disk, sector, 1, tmp_buf) != GRUB_ERR_NONE)
 566             goto finish;
 567
 568           sector++;
 569           buf = (char *) buf + len;
 570           size -= len;
 571           real_offset = 0;
 572         }
 573       else
 574         {
 575           grub_size_t len;
 576           grub_size_t n;
 577
 578           len = size & ~(GRUB_DISK_SECTOR_SIZE - 1);
 579           n = size >> GRUB_DISK_SECTOR_BITS;
 580
 581           if ((disk->dev->write) (disk, sector, n, buf) != GRUB_ERR_NONE)
 582             goto finish;
 583
 584           while (n--)
 585             grub_disk_cache_invalidate (disk->dev->id, disk->id, sector++);
 586
 587           buf = (char *) buf + len;
 588           size -= len;
 589         }
 590     }
 591
 592  finish:
 593
 594   return grub_errno;
 595 }
 596
 597 grub_uint64_t
 598 grub_disk_get_size (grub_disk_t disk)
 599 {
 600   if (disk->partition)
 601     return grub_partition_get_len (disk->partition);
 602   else
 603     return disk->total_sectors;
 604 }