/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2002,2003,2004,2006,2007,2008,2009,2010  Free Software Foundation, Inc.
 *
 *  GRUB is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  GRUB is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <grub/disk.h>
#include <grub/err.h>
#include <grub/mm.h>
#include <grub/types.h>
#include <grub/partition.h>
#include <grub/misc.h>
#include <grub/time.h>
#include <grub/file.h>
#include <grub/i18n.h>

#define	GRUB_CACHE_TIMEOUT	2

/* The last time the disk was used.  */
static grub_uint64_t grub_last_time = 0;

struct grub_disk_cache grub_disk_cache_table[GRUB_DISK_CACHE_NUM];

void (*grub_disk_firmware_fini) (void);
int grub_disk_firmware_is_tainted;

#if DISK_CACHE_STATS
static unsigned long grub_disk_cache_hits;
static unsigned long grub_disk_cache_misses;

void
grub_disk_cache_get_performance (unsigned long *hits, unsigned long *misses)
{
  *hits = grub_disk_cache_hits;
  *misses = grub_disk_cache_misses;
}
#endif

grub_err_t (*grub_disk_write_weak) (grub_disk_t disk,
                                    grub_disk_addr_t sector,
                                    grub_off_t offset,
                                    grub_size_t size,
                                    const void *buf);
#include "disk_common.c"

void
grub_disk_cache_invalidate_all (void)
{
  unsigned i;

  for (i = 0; i < GRUB_DISK_CACHE_NUM; i++) {
    struct grub_disk_cache *cache = grub_disk_cache_table + i;

    if (cache->data && ! cache->lock) {
      grub_free (cache->data);
      cache->data = 0;
    }
  }
}

static char *
grub_disk_cache_fetch (unsigned long dev_id, unsigned long disk_id,
                       grub_disk_addr_t sector)
{
  struct grub_disk_cache *cache;
  unsigned cache_index;

  cache_index = grub_disk_cache_get_index (dev_id, disk_id, sector);
  cache = grub_disk_cache_table + cache_index;

  if (cache->dev_id == dev_id && cache->disk_id == disk_id
      && cache->sector == sector) {
    cache->lock = 1;
#if DISK_CACHE_STATS
    grub_disk_cache_hits++;
#endif
    return cache->data;
  }

#if DISK_CACHE_STATS
  grub_disk_cache_misses++;
#endif

  return 0;
}

static void
grub_disk_cache_unlock (unsigned long dev_id, unsigned long disk_id,
                        grub_disk_addr_t sector)
{
  struct grub_disk_cache *cache;
  unsigned cache_index;

  cache_index = grub_disk_cache_get_index (dev_id, disk_id, sector);
  cache = grub_disk_cache_table + cache_index;

  if (cache->dev_id == dev_id && cache->disk_id == disk_id
      && cache->sector == sector) {
    cache->lock = 0;
  }
}

static grub_err_t
grub_disk_cache_store (unsigned long dev_id, unsigned long disk_id,
                       grub_disk_addr_t sector, const char *data)
{
  unsigned cache_index;
  struct grub_disk_cache *cache;

  cache_index = grub_disk_cache_get_index (dev_id, disk_id, sector);
  cache = grub_disk_cache_table + cache_index;

  cache->lock = 1;
  grub_free (cache->data);
  cache->data = 0;
  cache->lock = 0;

  cache->data = grub_malloc (GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS);
  if (! cache->data) {
    return grub_errno;
  }

  grub_memcpy (cache->data, data,
               GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS);
  cache->dev_id = dev_id;
  cache->disk_id = disk_id;
  cache->sector = sector;

  return GRUB_ERR_NONE;
}



grub_disk_dev_t grub_disk_dev_list;

void
grub_disk_dev_register (grub_disk_dev_t dev)
{
  dev->next = grub_disk_dev_list;
  grub_disk_dev_list = dev;
}

void
grub_disk_dev_unregister (grub_disk_dev_t dev)
{
  grub_disk_dev_t *p, q;

  for (p = &grub_disk_dev_list, q = *p; q; p = &(q->next), q = q->next) {
    if (q == dev) {
      *p = q->next;
      break;
    }
  }
}

/* Return the location of the first ',', if any, which is not
 escaped by a '\'.  */
static const char *
find_part_sep (const char *name)
{
  const char *p = name;
  char c;

  while ((c = *p++) != '\0') {
    if (c == '\\' && *p == ',')
      p++;
    else if (c == ',') {
      return p - 1;
    }
  }
  return NULL;
}

grub_disk_t
grub_disk_open (const char *name)
{
  const char *p;
  grub_disk_t disk;
  grub_disk_dev_t dev;
  char *raw = (char *) name;
  grub_uint64_t current_time;

  grub_dprintf ("disk", "Opening `%s'...\n", name);

  disk = (grub_disk_t) grub_zalloc (sizeof (*disk));
  if (! disk)
    return 0;
  disk->log_sector_size = GRUB_DISK_SECTOR_BITS;
  /* Default 1MiB of maximum agglomerate.  */
  disk->max_agglomerate = 1048576 >> (GRUB_DISK_SECTOR_BITS
                                      + GRUB_DISK_CACHE_BITS);

  p = find_part_sep (name);
  if (p) {
    grub_size_t len = p - name;

    raw = grub_malloc (len + 1);
    if (! raw)
      goto fail;

    grub_memcpy (raw, name, len);
    raw[len] = '\0';
    disk->name = grub_strdup (raw);
  } else {
    disk->name = grub_strdup (name);
  }
  if (! disk->name) {
    goto fail;
  }

  for (dev = grub_disk_dev_list; dev; dev = dev->next) {
    if ((dev->open) (raw, disk) == GRUB_ERR_NONE)
      break;
    else if (grub_errno == GRUB_ERR_UNKNOWN_DEVICE)
      grub_errno = GRUB_ERR_NONE;
    else
      goto fail;
  }

  if (! dev) {
    grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("disk `%s' not found"),
                name);
    goto fail;
  }
  if (disk->log_sector_size > GRUB_DISK_CACHE_BITS + GRUB_DISK_SECTOR_BITS
      || disk->log_sector_size < GRUB_DISK_SECTOR_BITS) {
    grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
                "sector sizes of %d bytes aren't supported yet",
                (1 << disk->log_sector_size));
    goto fail;
  }

  disk->dev = dev;

  if (p) {
    disk->partition = grub_partition_probe (disk, p + 1);
    if (! disk->partition) {
      /* TRANSLATORS: It means that the specified partition e.g.
       hd0,msdos1=/dev/sda1 doesn't exist.  */
      grub_error (GRUB_ERR_UNKNOWN_DEVICE, N_("no such partition"));
      goto fail;
    }
  }

  /* The cache will be invalidated about 2 seconds after a device was
   closed.  */
  current_time = grub_get_time_ms ();

  if (current_time > (grub_last_time
                      + GRUB_CACHE_TIMEOUT * 1000)) {
    grub_disk_cache_invalidate_all ();
  }

  grub_last_time = current_time;

fail:

  if (raw && raw != name)
    grub_free (raw);

  if (grub_errno != GRUB_ERR_NONE) {
    grub_error_push ();
    grub_dprintf ("disk", "Opening `%s' failed.\n", name);
    grub_error_pop ();

    grub_disk_close (disk);
    return 0;
  }

  return disk;
}

void
grub_disk_close (grub_disk_t disk)
{
  grub_partition_t part;
  grub_dprintf ("disk", "Closing `%s'.\n", disk->name);

  if (disk->dev && disk->dev->close)
    (disk->dev->close) (disk);

  /* Reset the timer.  */
  grub_last_time = grub_get_time_ms ();

  while (disk->partition) {
    part = disk->partition->parent;
    grub_free (disk->partition);
    disk->partition = part;
  }
  grub_free ((void *) disk->name);
  grub_free (disk);
}

/* Small read (less than cache size and not pass across cache unit boundaries).
 sector is already adjusted and is divisible by cache unit size.
 */
static grub_err_t
grub_disk_read_small_real (grub_disk_t disk, grub_disk_addr_t sector,
                           grub_off_t offset, grub_size_t size, void *buf)
{
  char *data;
  char *tmp_buf;

  /* Fetch the cache.  */
  data = grub_disk_cache_fetch (disk->dev->id, disk->id, sector);
  if (data) {
    /* Just copy it!  */
    grub_memcpy (buf, data + offset, size);
    grub_disk_cache_unlock (disk->dev->id, disk->id, sector);
    return GRUB_ERR_NONE;
  }

  /* Allocate a temporary buffer.  */
  tmp_buf = grub_malloc (GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS);
  if (! tmp_buf)
    return grub_errno;

  /* Otherwise read data from the disk actually.  */
  if (disk->total_sectors == GRUB_DISK_SIZE_UNKNOWN
      || sector + GRUB_DISK_CACHE_SIZE
      < (disk->total_sectors << (disk->log_sector_size - GRUB_DISK_SECTOR_BITS))) {
    grub_err_t err;
    err = (disk->dev->read) (disk, transform_sector (disk, sector),
                             1U << (GRUB_DISK_CACHE_BITS
                                    + GRUB_DISK_SECTOR_BITS
                                    - disk->log_sector_size), tmp_buf);
    if (!err) {
      /* Copy it and store it in the disk cache.  */
      grub_memcpy (buf, tmp_buf + offset, size);
      grub_disk_cache_store (disk->dev->id, disk->id,
                             sector, tmp_buf);
      grub_free (tmp_buf);
      return GRUB_ERR_NONE;
    }
  }

  grub_free (tmp_buf);
  grub_errno = GRUB_ERR_NONE;

  {
    /* Uggh... Failed. Instead, just read necessary data.  */
    unsigned num;
    grub_disk_addr_t aligned_sector;

    sector += (offset >> GRUB_DISK_SECTOR_BITS);
    offset &= ((1 << GRUB_DISK_SECTOR_BITS) - 1);
    aligned_sector = (sector & ~((1ULL << (disk->log_sector_size
                                           - GRUB_DISK_SECTOR_BITS))
                                 - 1));
    offset += ((sector - aligned_sector) << GRUB_DISK_SECTOR_BITS);
    num = ((size + offset + (1ULL << (disk->log_sector_size))
            - 1) >> (disk->log_sector_size));

    tmp_buf = grub_malloc (num << disk->log_sector_size);
    if (!tmp_buf)
      return grub_errno;

    if ((disk->dev->read) (disk, transform_sector (disk, aligned_sector),
                           num, tmp_buf))
    {
      grub_error_push ();
      grub_dprintf ("disk", "%s read failed\n", disk->name);
      grub_error_pop ();
      grub_free (tmp_buf);
      return grub_errno;
    }
    grub_memcpy (buf, tmp_buf + offset, size);
    grub_free (tmp_buf);
    return GRUB_ERR_NONE;
  }
}

static grub_err_t
grub_disk_read_small (grub_disk_t disk, grub_disk_addr_t sector,
                      grub_off_t offset, grub_size_t size, void *buf)
{
  grub_err_t err;

  err = grub_disk_read_small_real (disk, sector, offset, size, buf);
  if (err)
    return err;
  if (disk->read_hook)
    (disk->read_hook) (sector + (offset >> GRUB_DISK_SECTOR_BITS),
                       offset & (GRUB_DISK_SECTOR_SIZE - 1),
                       size, disk->read_hook_data);
  return GRUB_ERR_NONE;
}

/* Read data from the disk.  */
grub_err_t
grub_disk_read (grub_disk_t disk, grub_disk_addr_t sector,
                grub_off_t offset, grub_size_t size, void *buf)
{
  /* First of all, check if the region is within the disk.  */
  if (grub_disk_adjust_range (disk, &sector, &offset, size) != GRUB_ERR_NONE) {
    grub_error_push ();
    grub_dprintf ("disk", "Read out of range: sector 0x%llx (%s).\n",
                  (unsigned long long) sector, grub_errmsg);
    grub_error_pop ();
    return grub_errno;
  }

  /* First read until first cache boundary.   */
  if (offset || (sector & (GRUB_DISK_CACHE_SIZE - 1))) {
    grub_disk_addr_t start_sector;
    grub_size_t pos;
    grub_err_t err;
    grub_size_t len;

    start_sector = sector & ~((grub_disk_addr_t) GRUB_DISK_CACHE_SIZE - 1);
    pos = (sector - start_sector) << GRUB_DISK_SECTOR_BITS;
    len = ((GRUB_DISK_SECTOR_SIZE << GRUB_DISK_CACHE_BITS)
           - pos - offset);
    if (len > size)
      len = size;
    err = grub_disk_read_small (disk, start_sector,
                                offset + pos, len, buf);
    if (err)
      return err;
    buf = (char *) buf + len;
    size -= len;
    offset += len;
    sector += (offset >> GRUB_DISK_SECTOR_BITS);
    offset &= ((1 << GRUB_DISK_SECTOR_BITS) - 1);
  }

  /* Until SIZE is zero...  */
  while (size >= (GRUB_DISK_CACHE_SIZE << GRUB_DISK_SECTOR_BITS)) {
    char *data = NULL;
    grub_disk_addr_t agglomerate;
    grub_err_t err;

    /* agglomerate read until we find a first cached entry.  */
    for (agglomerate = 0; agglomerate
         < (size >> (GRUB_DISK_SECTOR_BITS + GRUB_DISK_CACHE_BITS))
         && agglomerate < disk->max_agglomerate;
         agglomerate++) {
      data = grub_disk_cache_fetch (disk->dev->id, disk->id,
                                    sector + (agglomerate
                                              << GRUB_DISK_CACHE_BITS));
      if (data)
        break;
    }

    if (data) {
      grub_memcpy ((char *) buf
                   + (agglomerate << (GRUB_DISK_CACHE_BITS
                                      + GRUB_DISK_SECTOR_BITS)),
                   data, GRUB_DISK_CACHE_SIZE << GRUB_DISK_SECTOR_BITS);
      grub_disk_cache_unlock (disk->dev->id, disk->id,
                              sector + (agglomerate
                                        << GRUB_DISK_CACHE_BITS));
    }

    if (agglomerate) {
      grub_disk_addr_t i;

      err = (disk->dev->read) (disk, transform_sector (disk, sector),
                               agglomerate << (GRUB_DISK_CACHE_BITS
                                               + GRUB_DISK_SECTOR_BITS
                                               - disk->log_sector_size),
                               buf);
      if (err)
        return err;

      for (i = 0; i < agglomerate; i ++) {
        grub_disk_cache_store (disk->dev->id, disk->id,
                               sector + (i << GRUB_DISK_CACHE_BITS),
                               (char *) buf
                               + (i << (GRUB_DISK_CACHE_BITS
                                        + GRUB_DISK_SECTOR_BITS)));
      }


      if (disk->read_hook) {
        (disk->read_hook) (sector, 0, agglomerate << (GRUB_DISK_CACHE_BITS + GRUB_DISK_SECTOR_BITS),
                           disk->read_hook_data);
      }

      sector += agglomerate << GRUB_DISK_CACHE_BITS;
      size -= agglomerate << (GRUB_DISK_CACHE_BITS + GRUB_DISK_SECTOR_BITS);
      buf = (char *) buf 
      + (agglomerate << (GRUB_DISK_CACHE_BITS + GRUB_DISK_SECTOR_BITS));
    }
    
    if (data) {
      if (disk->read_hook) {
        (disk->read_hook) (sector, 0, (GRUB_DISK_CACHE_SIZE << GRUB_DISK_SECTOR_BITS),
                           disk->read_hook_data);
      }
      sector += GRUB_DISK_CACHE_SIZE;
      buf = (char *) buf + (GRUB_DISK_CACHE_SIZE << GRUB_DISK_SECTOR_BITS);
      size -= (GRUB_DISK_CACHE_SIZE << GRUB_DISK_SECTOR_BITS);
    }
  }
  
  /* And now read the last part.  */
  if (size) {
    grub_err_t err;
    err = grub_disk_read_small (disk, sector, 0, size, buf);
    if (err) {
      return err;
    }
  }
  
  return grub_errno;
}

grub_uint64_t
grub_disk_get_size (grub_disk_t disk)
{
  if (disk->partition)
    return grub_partition_get_len (disk->partition);
  else if (disk->total_sectors != GRUB_DISK_SIZE_UNKNOWN)
    return disk->total_sectors << (disk->log_sector_size - GRUB_DISK_SECTOR_BITS);
  else
    return GRUB_DISK_SIZE_UNKNOWN;
}
