/*
 * ntloader  --  Microsoft Windows NT6+ loader
 * Copyright (C) 2023  A1ive.
 *
 * This program 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 2 of the
 * License, or (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <strings.h>
#include <msdos.h>
#include <fsuuid.h>
#include <cmdline.h>
#include <ntboot.h>

static unsigned part_count = 0;

static int
check_mbr (void *disk, uint32_t start_lba, int (*disk_read)
              (void *disk, uint64_t sector, size_t len, void *buf))
{
  int i;
  struct msdos_part_mbr mbr;
  uint64_t start_addr;

  if (!disk_read (disk, start_lba, sizeof (mbr), &mbr))
    return 0;
  if (mbr.signature != MSDOS_PART_SIGNATURE)
  {
    DBG ("MSDOS partition signature not found.\n");
    return 0;
  }

  for (i = 0; i < MSDOS_MAX_PARTITIONS; i++)
  {
    if (part_count >= 32)
    {
      DBG ("too many partitions.\n");
      return 0;
    }
    if (mbr.entries[i].type == MSDOS_PART_TYPE_GPT_DISK)
    {
      DBG ("found dummy mbr.\n");
      return 0;
    }
    if (! mbr.entries[i].length || msdos_part_is_empty (mbr.entries[i].type))
      continue;
    if (msdos_part_is_extended (mbr.entries[i].type))
    {
      if (check_mbr (disk, start_lba + mbr.entries[i].start, disk_read))
        return 1;
      continue;
    }
    DBG ("part %d (%d) ", part_count++, i);
    if (check_fsuuid (disk, start_lba + mbr.entries[i].start, disk_read))
    {
      start_addr = ((uint64_t) mbr.entries[i].start + start_lba) << 9;
      DBG ("MBR Start=0x%llx Signature=%04X\n", start_addr, mbr.unique_signature);
      memcpy (nt_cmdline->info.partid, &start_addr, sizeof (start_addr));
      nt_cmdline->info.partmap = 0x01;
      memcpy (nt_cmdline->info.diskid, &mbr.unique_signature, sizeof (uint32_t));
      return 1;
    }
  }
  return 0;
}

int
check_msdos_partmap (void *disk,
                     int (*disk_read) (void *disk, uint64_t sector,
                                       size_t len, void *buf))
{
  part_count = 0;
  return check_mbr (disk, 0, disk_read);
}