232 lines
6.7 KiB
C
232 lines
6.7 KiB
C
/* gpt.c - Read GUID Partition Tables (GPT). */
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/*
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* VasEBoot -- 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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* VasEBoot 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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* VasEBoot 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 VasEBoot. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <VasEBoot/disk.h>
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#include <VasEBoot/misc.h>
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#include <VasEBoot/mm.h>
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#include <VasEBoot/partition.h>
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#include <VasEBoot/dl.h>
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#include <VasEBoot/msdos_partition.h>
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#include <VasEBoot/gpt_partition.h>
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#include <VasEBoot/i18n.h>
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VasEBoot_MOD_LICENSE ("GPLv3+");
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static VasEBoot_uint8_t VasEBoot_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 VasEBoot_gpt_part_type_t VasEBoot_gpt_partition_type_empty = VasEBoot_GPT_PARTITION_TYPE_EMPTY;
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#ifdef VasEBoot_UTIL
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static const VasEBoot_gpt_part_type_t VasEBoot_gpt_partition_type_bios_boot = VasEBoot_GPT_PARTITION_TYPE_BIOS_BOOT;
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#endif
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/* 512 << 7 = 65536 byte sectors. */
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#define MAX_SECTOR_LOG 7
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static struct VasEBoot_partition_map VasEBoot_gpt_partition_map;
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VasEBoot_err_t
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VasEBoot_gpt_partition_map_iterate (VasEBoot_disk_t disk,
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VasEBoot_partition_iterate_hook_t hook,
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void *hook_data)
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{
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struct VasEBoot_partition part;
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struct VasEBoot_gpt_header gpt;
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struct VasEBoot_gpt_partentry entry;
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struct VasEBoot_msdos_partition_mbr mbr;
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VasEBoot_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 (VasEBoot_disk_read (disk, 0, 0, sizeof (mbr), &mbr))
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return VasEBoot_errno;
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/* Check if it is valid. */
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if (mbr.signature != VasEBoot_cpu_to_le16_compile_time (VasEBoot_PC_PARTITION_SIGNATURE))
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return VasEBoot_error (VasEBoot_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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for (i = 0; i < 4; i++)
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if (mbr.entries[i].type == VasEBoot_PC_PARTITION_TYPE_GPT_DISK)
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break;
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if (i == 4)
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return VasEBoot_error (VasEBoot_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 (VasEBoot_disk_read (disk, 1 << sector_log, 0, sizeof (gpt), &gpt))
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return VasEBoot_errno;
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if (VasEBoot_memcmp (gpt.magic, VasEBoot_gpt_magic, sizeof (VasEBoot_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 VasEBoot_error (VasEBoot_ERR_BAD_PART_TABLE, "no valid GPT header");
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VasEBoot_dprintf ("gpt", "Read a valid GPT header\n");
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entries = VasEBoot_le_to_cpu64 (gpt.partitions) << sector_log;
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for (i = 0; i < VasEBoot_le_to_cpu32 (gpt.maxpart); i++)
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{
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if (VasEBoot_disk_read (disk, entries, last_offset,
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sizeof (entry), &entry))
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return VasEBoot_errno;
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if (VasEBoot_memcmp (&VasEBoot_gpt_partition_type_empty, &entry.type,
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sizeof (VasEBoot_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 = VasEBoot_le_to_cpu64 (entry.start) << sector_log;
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part.len = (VasEBoot_le_to_cpu64 (entry.end)
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- VasEBoot_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 = &VasEBoot_gpt_partition_map;
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part.parent = disk->partition;
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VasEBoot_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, hook_data))
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return VasEBoot_errno;
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}
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last_offset += VasEBoot_le_to_cpu32 (gpt.partentry_size);
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if (last_offset == VasEBoot_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 VasEBoot_ERR_NONE;
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}
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#ifdef VasEBoot_UTIL
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/* Context for gpt_partition_map_embed. */
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struct gpt_partition_map_embed_ctx
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{
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VasEBoot_disk_addr_t start, len;
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};
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/* Helper for gpt_partition_map_embed. */
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static int
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find_usable_region (VasEBoot_disk_t disk __attribute__ ((unused)),
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const VasEBoot_partition_t p, void *data)
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{
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struct gpt_partition_map_embed_ctx *ctx = data;
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struct VasEBoot_gpt_partentry gptdata;
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VasEBoot_partition_t p2;
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p2 = disk->partition;
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disk->partition = p->parent;
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if (VasEBoot_disk_read (disk, p->offset, p->index,
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sizeof (gptdata), &gptdata))
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{
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disk->partition = p2;
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return 0;
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}
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disk->partition = p2;
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/* If there's an embed region, it is in a dedicated partition. */
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if (! VasEBoot_memcmp (&gptdata.type, &VasEBoot_gpt_partition_type_bios_boot, 16))
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{
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ctx->start = p->start;
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ctx->len = p->len;
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return 1;
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}
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return 0;
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}
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static VasEBoot_err_t
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gpt_partition_map_embed (struct VasEBoot_disk *disk, unsigned int *nsectors,
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unsigned int max_nsectors,
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VasEBoot_embed_type_t embed_type,
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VasEBoot_disk_addr_t **sectors)
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{
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struct gpt_partition_map_embed_ctx ctx = {
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.start = 0,
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.len = 0
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};
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unsigned i;
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VasEBoot_err_t err;
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if (embed_type != VasEBoot_EMBED_PCBIOS)
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return VasEBoot_error (VasEBoot_ERR_NOT_IMPLEMENTED_YET,
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"GPT currently supports only PC-BIOS embedding");
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err = VasEBoot_gpt_partition_map_iterate (disk, find_usable_region, &ctx);
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if (err)
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return err;
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if (ctx.len == 0)
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return VasEBoot_error (VasEBoot_ERR_FILE_NOT_FOUND,
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N_("this GPT partition label contains no BIOS Boot Partition;"
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" embedding won't be possible"));
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if (ctx.len < *nsectors)
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return VasEBoot_error (VasEBoot_ERR_OUT_OF_RANGE,
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N_("your BIOS Boot Partition is too small;"
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" embedding won't be possible"));
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*nsectors = ctx.len;
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if (*nsectors > max_nsectors)
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*nsectors = max_nsectors;
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*sectors = VasEBoot_malloc (*nsectors * sizeof (**sectors));
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if (!*sectors)
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return VasEBoot_errno;
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for (i = 0; i < *nsectors; i++)
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(*sectors)[i] = ctx.start + i;
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return VasEBoot_ERR_NONE;
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}
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#endif
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/* Partition map type. */
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static struct VasEBoot_partition_map VasEBoot_gpt_partition_map =
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{
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.name = "gpt",
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.iterate = VasEBoot_gpt_partition_map_iterate,
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#ifdef VasEBoot_UTIL
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.embed = gpt_partition_map_embed
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#endif
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};
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VasEBoot_MOD_INIT(part_gpt)
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{
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VasEBoot_partition_map_register (&VasEBoot_gpt_partition_map);
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}
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VasEBoot_MOD_FINI(part_gpt)
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{
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VasEBoot_partition_map_unregister (&VasEBoot_gpt_partition_map);
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}
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