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 grub_disk_t
 219 grub_disk_open (const char *name)
 220 {
 221   char *p;
 222   grub_disk_t disk;
 223   grub_disk_dev_t dev;
 224   char *raw = (char *) name;
 225   grub_uint64_t current_time;
 226
 227   grub_dprintf ("disk", "Opening `%s'...\n", name);
 228
 229   disk = (grub_disk_t) grub_malloc (sizeof (*disk));
 230   if (! disk)
 231     return 0;
 232
 233   disk->dev = 0;
 234   disk->read_hook = 0;
 235   disk->partition = 0;
 236   disk->data = 0;
 237   disk->name = grub_strdup (name);
 238   if (! disk->name)
 239     goto fail;
 240
 241   p = grub_strchr (name, ',');
 242   if (p)
 243     {
 244       grub_size_t len = p - name;
 245
 246       raw = grub_malloc (len + 1);
 247       if (! raw)
 248         goto fail;
 249
 250       grub_memcpy (raw, name, len);
 251       raw[len] = '\0';
 252     }
 253
 254   for (dev = grub_disk_dev_list; dev; dev = dev->next)
 255     {
 256       if ((dev->open) (raw, disk) == GRUB_ERR_NONE)
 257         break;
 258       else if (grub_errno == GRUB_ERR_UNKNOWN_DEVICE)
 259         grub_errno = GRUB_ERR_NONE;
 260       else
 261         goto fail;
 262     }
 263
 264   if (! dev)
 265     {
 266       grub_error (GRUB_ERR_UNKNOWN_DEVICE, "no such disk");
 267       goto fail;
 268     }
 269
 270   if (p && ! disk->has_partitions)
 271     {
 272       grub_error (GRUB_ERR_BAD_DEVICE, "no partition on this disk");
 273       goto fail;
 274     }
 275
 276   disk->dev = dev;
 277
 278   if (p)
 279     {
 280       disk->partition = grub_partition_probe (disk, p + 1);
 281       if (! disk->partition)
 282         {
 283           grub_error (GRUB_ERR_UNKNOWN_DEVICE, "no such partition");
 284           goto fail;
 285         }
 286     }
 287
 288   /* The cache will be invalidated about 2 seconds after a device was
 289      closed.  */
 290   current_time = grub_get_time_ms ();
 291
 292   if (current_time > (grub_last_time
 293                       + GRUB_CACHE_TIMEOUT * 1000))
 294     grub_disk_cache_invalidate_all ();
 295
 296   grub_last_time = current_time;
 297
 298  fail:
 299
 300   if (raw && raw != name)
 301     grub_free (raw);
 302
 303   if (grub_errno != GRUB_ERR_NONE)
 304     {
 305       grub_error_push ();
 306       grub_dprintf ("disk", "Opening `%s' failed.\n", name);
 307       grub_error_pop ();
 308
 309       grub_disk_close (disk);
 310       return 0;
 311     }
 312
 313   return disk;
 314 }
 315
 316 void
 317 grub_disk_close (grub_disk_t disk)
 318 {
 319   grub_dprintf ("disk", "Closing `%s'.\n", disk->name);
 320
 321   if (disk->dev && disk->dev->close)
 322     (disk->dev->close) (disk);
 323
 324   /* Reset the timer.  */
 325   grub_last_time = grub_get_time_ms ();
 326
 327   grub_free (disk->partition);
 328   grub_free ((void *) disk->name);
 329   grub_free (disk);
 330 }
 331
 332 /* This function performs three tasks:
 333    - Make sectors disk relative from partition relative.
 334    - Normalize offset to be less than the sector size.
 335    - Verify that the range is inside the partition.  */
 336 static grub_err_t
 337 grub_disk_adjust_range (grub_disk_t disk, grub_disk_addr_t *sector,
 338                        grub_off_t *offset, grub_size_t size)
 339 {
 340   *sector += *offset >> GRUB_DISK_SECTOR_BITS;
 341   *offset &= GRUB_DISK_SECTOR_SIZE - 1;
 342
 343   if (disk->partition)
 344     {
 345       grub_disk_addr_t start;
 346       grub_uint64_t len;
 347
 348       start = grub_partition_get_start (disk->partition);
 349       len = grub_partition_get_len (disk->partition);
 350
 351       if (*sector >= len
 352           || len - *sector < ((*offset + size + GRUB_DISK_SECTOR_SIZE - 1)
 353                               >> GRUB_DISK_SECTOR_BITS))
 354         return grub_error (GRUB_ERR_OUT_OF_RANGE, "out of partition");
 355
 356       *sector += start;
 357     }
 358
 359   if (disk->total_sectors <= *sector
 360       || ((*offset + size + GRUB_DISK_SECTOR_SIZE - 1)
 361           >> GRUB_DISK_SECTOR_BITS) > disk->total_sectors - *sector)
 362     return grub_error (GRUB_ERR_OUT_OF_RANGE, "out of disk");
 363
 364   return GRUB_ERR_NONE;
 365 }
 366
 367 /* Read data from the disk.  */
 368 grub_err_t
 369 grub_disk_read (grub_disk_t disk, grub_disk_addr_t sector,
 370                 grub_off_t offset, grub_size_t size, char *buf)
 371 {
 372   char *tmp_buf;
 373   unsigned real_offset;
 374
 375   grub_dprintf ("disk", "Reading `%s'...\n", disk->name);
 376
 377   /* First of all, check if the region is within the disk.  */
 378   if (grub_disk_adjust_range (disk, &sector, &offset, size) != GRUB_ERR_NONE)
 379     {
 380       grub_error_push ();
 381       grub_dprintf ("disk", "Read out of range: sector 0x%llx (%s).\n",
 382                     (unsigned long long) sector, grub_errmsg);
 383       grub_error_pop ();
 384       return grub_errno;
 385     }
 386
 387   real_offset = offset;
 388
 389   /* Allocate a temporary buffer.  */
 390   tmp_buf = grub_malloc (GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS);
 391   if (! tmp_buf)
 392     return grub_errno;
 393
 394   /* Until SIZE is zero...  */
 395   while (size)
 396     {
 397       char *data;
 398       grub_disk_addr_t start_sector;
 399       grub_size_t len;
 400       grub_size_t pos;
 401
 402       /* For reading bulk data.  */
 403       start_sector = sector & ~(GRUB_DISK_CACHE_SIZE - 1);
 404       pos = (sector - start_sector) << GRUB_DISK_SECTOR_BITS;
 405       len = ((GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS)
 406              - pos - real_offset);
 407       if (len > size)
 408         len = size;
 409
 410       /* Fetch the cache.  */
 411       data = grub_disk_cache_fetch (disk->dev->id, disk->id, start_sector);
 412       if (data)
 413         {
 414           /* Just copy it!  */
 415           grub_memcpy (buf, data + pos + real_offset, len);
 416           grub_disk_cache_unlock (disk->dev->id, disk->id, start_sector);
 417         }
 418       else
 419         {
 420           /* Otherwise read data from the disk actually.  */
 421           if ((disk->dev->read) (disk, start_sector,
 422                                  GRUB_DISK_CACHE_SIZE, tmp_buf)
 423               != GRUB_ERR_NONE)
 424             {
 425               /* Uggh... Failed. Instead, just read necessary data.  */
 426               unsigned num;
 427               char *p;
 428
 429               grub_errno = GRUB_ERR_NONE;
 430
 431               num = ((size + GRUB_DISK_SECTOR_SIZE - 1)
 432                      >> GRUB_DISK_SECTOR_BITS);
 433
 434               p = grub_realloc (tmp_buf, num << GRUB_DISK_SECTOR_BITS);
 435               if (!p)
 436                 goto finish;
 437
 438               tmp_buf = p;
 439
 440               if ((disk->dev->read) (disk, sector, num, tmp_buf))
 441                 {
 442                   grub_error_push ();
 443                   grub_dprintf ("disk", "%s read failed\n", disk->name);
 444                   grub_error_pop ();
 445                   goto finish;
 446                 }
 447
 448               grub_memcpy (buf, tmp_buf + real_offset, size);
 449
 450               /* Call the read hook, if any.  */
 451               if (disk->read_hook)
 452                 while (size)
 453                   {
 454                     (disk->read_hook) (sector, real_offset,
 455                                        ((size > GRUB_DISK_SECTOR_SIZE)
 456                                         ? GRUB_DISK_SECTOR_SIZE
 457                                         : size));
 458                     sector++;
 459                     size -= GRUB_DISK_SECTOR_SIZE - real_offset;
 460                     real_offset = 0;
 461                   }
 462
 463               /* This must be the end.  */
 464               goto finish;
 465             }
 466
 467           /* Copy it and store it in the disk cache.  */
 468           grub_memcpy (buf, tmp_buf + pos + real_offset, len);
 469           grub_disk_cache_store (disk->dev->id, disk->id,
 470                                  start_sector, tmp_buf);
 471         }
 472
 473       /* Call the read hook, if any.  */
 474       if (disk->read_hook)
 475         {
 476           grub_disk_addr_t s = sector;
 477           grub_size_t l = len;
 478
 479           while (l)
 480             {
 481               (disk->read_hook) (s, real_offset,
 482                                  ((l > GRUB_DISK_SECTOR_SIZE)
 483                                   ? GRUB_DISK_SECTOR_SIZE
 484                                   : l));
 485
 486               if (l < GRUB_DISK_SECTOR_SIZE - real_offset)
 487                 break;
 488
 489               s++;
 490               l -= GRUB_DISK_SECTOR_SIZE - real_offset;
 491               real_offset = 0;
 492             }
 493         }
 494
 495       sector = start_sector + GRUB_DISK_CACHE_SIZE;
 496       buf += len;
 497       size -= len;
 498       real_offset = 0;
 499     }
 500
 501  finish:
 502
 503   grub_free (tmp_buf);
 504
 505   return grub_errno;
 506 }
 507
 508 grub_err_t
 509 grub_disk_write (grub_disk_t disk, grub_disk_addr_t sector,
 510                  grub_off_t offset, grub_size_t size, const char *buf)
 511 {
 512   unsigned real_offset;
 513
 514   grub_dprintf ("disk", "Writing `%s'...\n", disk->name);
 515
 516   if (grub_disk_adjust_range (disk, &sector, &offset, size) != GRUB_ERR_NONE)
 517     return -1;
 518
 519   real_offset = offset;
 520
 521   while (size)
 522     {
 523       if (real_offset != 0 || (size < GRUB_DISK_SECTOR_SIZE && size != 0))
 524         {
 525           char tmp_buf[GRUB_DISK_SECTOR_SIZE];
 526           grub_size_t len;
 527
 528           if (grub_disk_read (disk, sector, 0, GRUB_DISK_SECTOR_SIZE, tmp_buf)
 529               != GRUB_ERR_NONE)
 530             goto finish;
 531
 532           len = GRUB_DISK_SECTOR_SIZE - real_offset;
 533           if (len > size)
 534             len = size;
 535
 536           grub_memcpy (tmp_buf + real_offset, buf, len);
 537
 538           grub_disk_cache_invalidate (disk->dev->id, disk->id, sector);
 539
 540           if ((disk->dev->write) (disk, sector, 1, tmp_buf) != GRUB_ERR_NONE)
 541             goto finish;
 542
 543           sector++;
 544           buf += len;
 545           size -= len;
 546           real_offset = 0;
 547         }
 548       else
 549         {
 550           grub_size_t len;
 551           grub_size_t n;
 552
 553           len = size & ~(GRUB_DISK_SECTOR_SIZE - 1);
 554           n = size >> GRUB_DISK_SECTOR_BITS;
 555
 556           if ((disk->dev->write) (disk, sector, n, buf) != GRUB_ERR_NONE)
 557             goto finish;
 558
 559           while (n--)
 560             grub_disk_cache_invalidate (disk->dev->id, disk->id, sector++);
 561
 562           buf += len;
 563           size -= len;
 564         }
 565     }
 566
 567  finish:
 568
 569   return grub_errno;
 570 }
 571
 572 grub_uint64_t
 573 grub_disk_get_size (grub_disk_t disk)
 574 {
 575   if (disk->partition)
 576     return grub_partition_get_len (disk->partition);
 577   else
 578     return disk->total_sectors;
 579 }