136 lines
3.9 KiB
C
136 lines
3.9 KiB
C
/* gpt.c - Read GUID Partition Tables (GPT). */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2002,2005,2006,2007,2008 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/disk.h>
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#include <grub/misc.h>
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#include <grub/mm.h>
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#include <grub/partition.h>
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#include <grub/dl.h>
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#include <grub/msdos_partition.h>
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#include <grub/gpt_partition.h>
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static grub_uint8_t grub_gpt_magic[8] =
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{
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0x45, 0x46, 0x49, 0x20, 0x50, 0x41, 0x52, 0x54
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};
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static const grub_gpt_part_type_t grub_gpt_partition_type_empty = GRUB_GPT_PARTITION_TYPE_EMPTY;
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/* 512 << 7 = 65536 byte sectors. */
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#define MAX_SECTOR_LOG 7
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static struct grub_partition_map grub_gpt_partition_map;
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static grub_err_t
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gpt_partition_map_iterate (grub_disk_t disk,
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int (*hook) (grub_disk_t disk,
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const grub_partition_t partition))
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{
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struct grub_partition part;
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struct grub_gpt_header gpt;
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struct grub_gpt_partentry entry;
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struct grub_msdos_partition_mbr mbr;
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grub_uint64_t entries;
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unsigned int i;
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int last_offset = 0;
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int sector_log = 0;
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/* Read the protective MBR. */
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if (grub_disk_read (disk, 0, 0, sizeof (mbr), &mbr))
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return grub_errno;
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/* Check if it is valid. */
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if (mbr.signature != grub_cpu_to_le16 (GRUB_PC_PARTITION_SIGNATURE))
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return grub_error (GRUB_ERR_BAD_PART_TABLE, "no signature");
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/* Make sure the MBR is a protective MBR and not a normal MBR. */
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if (mbr.entries[0].type != GRUB_PC_PARTITION_TYPE_GPT_DISK)
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return grub_error (GRUB_ERR_BAD_PART_TABLE, "no GPT partition map found");
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/* Read the GPT header. */
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for (sector_log = 0; sector_log < MAX_SECTOR_LOG; sector_log++)
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{
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if (grub_disk_read (disk, 1 << sector_log, 0, sizeof (gpt), &gpt))
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return grub_errno;
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if (grub_memcmp (gpt.magic, grub_gpt_magic, sizeof (grub_gpt_magic)) == 0)
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break;
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}
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if (sector_log == MAX_SECTOR_LOG)
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return grub_error (GRUB_ERR_BAD_PART_TABLE, "no valid GPT header");
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grub_dprintf ("gpt", "Read a valid GPT header\n");
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entries = grub_le_to_cpu64 (gpt.partitions) << sector_log;
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for (i = 0; i < grub_le_to_cpu32 (gpt.maxpart); i++)
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{
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if (grub_disk_read (disk, entries, last_offset,
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sizeof (entry), &entry))
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return grub_errno;
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if (grub_memcmp (&grub_gpt_partition_type_empty, &entry.type,
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sizeof (grub_gpt_partition_type_empty)))
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{
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/* Calculate the first block and the size of the partition. */
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part.start = grub_le_to_cpu64 (entry.start) << sector_log;
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part.len = (grub_le_to_cpu64 (entry.end)
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- grub_le_to_cpu64 (entry.start) + 1) << sector_log;
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part.offset = entries;
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part.number = i;
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part.index = last_offset;
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part.partmap = &grub_gpt_partition_map;
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grub_dprintf ("gpt", "GPT entry %d: start=%lld, length=%lld\n", i,
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(unsigned long long) part.start,
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(unsigned long long) part.len);
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if (hook (disk, &part))
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return grub_errno;
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}
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last_offset += grub_le_to_cpu32 (gpt.partentry_size);
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if (last_offset == GRUB_DISK_SECTOR_SIZE)
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{
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last_offset = 0;
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entries++;
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}
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}
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return GRUB_ERR_NONE;
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}
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/* Partition map type. */
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static struct grub_partition_map grub_gpt_partition_map =
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{
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.name = "gpt",
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.iterate = gpt_partition_map_iterate,
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};
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GRUB_MOD_INIT(part_gpt)
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{
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grub_partition_map_register (&grub_gpt_partition_map);
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}
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GRUB_MOD_FINI(part_gpt)
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{
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grub_partition_map_unregister (&grub_gpt_partition_map);
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}
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