+/* gpt.c - Read GUID Partition Tables (GPT). */
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2002,2005,2006,2007,2008 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/misc.h>
+#include <grub/mm.h>
+#include <grub/partition.h>
+#include <grub/dl.h>
+#include <grub/msdos_partition.h>
+#include <grub/gpt_partition.h>
+#include <grub/i18n.h>
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+static grub_uint8_t grub_gpt_magic[8] =
+ {
+ 0x45, 0x46, 0x49, 0x20, 0x50, 0x41, 0x52, 0x54
+ };
+
+static const grub_gpt_part_guid_t grub_gpt_partition_type_empty = GRUB_GPT_PARTITION_TYPE_EMPTY;
+
+#ifdef GRUB_UTIL
+static const grub_gpt_part_guid_t grub_gpt_partition_type_bios_boot = GRUB_GPT_PARTITION_TYPE_BIOS_BOOT;
+#endif
+
+/* 512 << 7 = 65536 byte sectors. */
+#define MAX_SECTOR_LOG 7
+
+static struct grub_partition_map grub_gpt_partition_map;
+
+\f
+
+grub_err_t
+grub_gpt_partition_map_iterate (grub_disk_t disk,
+ grub_partition_iterate_hook_t hook,
+ void *hook_data)
+{
+ struct grub_partition part;
+ struct grub_gpt_header gpt;
+ struct grub_gpt_partentry entry;
+ struct grub_msdos_partition_mbr mbr;
+ grub_uint64_t entries;
+ unsigned int i;
+ int last_offset = 0;
+ int sector_log = 0;
+
+ /* Read the protective MBR. */
+ if (grub_disk_read (disk, 0, 0, sizeof (mbr), &mbr))
+ return grub_errno;
+
+ /* Check if it is valid. */
+ if (mbr.signature != grub_cpu_to_le16_compile_time (GRUB_PC_PARTITION_SIGNATURE))
+ return grub_error (GRUB_ERR_BAD_PART_TABLE, "no signature");
+
+ /* Make sure the MBR is a protective MBR and not a normal MBR. */
+ for (i = 0; i < 4; i++)
+ if (mbr.entries[i].type == GRUB_PC_PARTITION_TYPE_GPT_DISK)
+ break;
+ if (i == 4)
+ return grub_error (GRUB_ERR_BAD_PART_TABLE, "no GPT partition map found");
+
+ /* Read the GPT header. */
+ for (sector_log = 0; sector_log < MAX_SECTOR_LOG; sector_log++)
+ {
+ if (grub_disk_read (disk, 1 << sector_log, 0, sizeof (gpt), &gpt))
+ return grub_errno;
+
+ if (grub_memcmp (gpt.magic, grub_gpt_magic, sizeof (grub_gpt_magic)) == 0)
+ break;
+ }
+ if (sector_log == MAX_SECTOR_LOG)
+ return grub_error (GRUB_ERR_BAD_PART_TABLE, "no valid GPT header");
+
+ grub_dprintf ("gpt", "Read a valid GPT header\n");
+
+ entries = grub_le_to_cpu64 (gpt.partitions) << sector_log;
+ for (i = 0; i < grub_le_to_cpu32 (gpt.maxpart); i++)
+ {
+ if (grub_disk_read (disk, entries, last_offset,
+ sizeof (entry), &entry))
+ return grub_errno;
+
+ if (grub_memcmp (&grub_gpt_partition_type_empty, &entry.type,
+ sizeof (grub_gpt_partition_type_empty)))
+ {
+ /* Calculate the first block and the size of the partition. */
+ part.start = grub_le_to_cpu64 (entry.start) << sector_log;
+ part.len = (grub_le_to_cpu64 (entry.end)
+ - grub_le_to_cpu64 (entry.start) + 1) << sector_log;
+ part.offset = entries;
+ part.number = i;
+ part.index = last_offset;
+ part.partmap = &grub_gpt_partition_map;
+ part.parent = disk->partition;
+ part.gpt_attrib = entry.attrib;
+
+ grub_dprintf ("gpt", "GPT entry %d: start=%lld, length=%lld\n", i,
+ (unsigned long long) part.start,
+ (unsigned long long) part.len);
+
+ if (hook (disk, &part, hook_data))
+ return grub_errno;
+ }
+
+ last_offset += grub_le_to_cpu32 (gpt.partentry_size);
+ if (last_offset == GRUB_DISK_SECTOR_SIZE)
+ {
+ last_offset = 0;
+ entries++;
+ }
+ }
+
+ return GRUB_ERR_NONE;
+}
+
+#ifdef GRUB_UTIL
+/* Context for gpt_partition_map_embed. */
+struct gpt_partition_map_embed_ctx
+{
+ grub_disk_addr_t start, len;
+};
+
+/* Helper for gpt_partition_map_embed. */
+static int
+find_usable_region (grub_disk_t disk __attribute__ ((unused)),
+ const grub_partition_t p, void *data)
+{
+ struct gpt_partition_map_embed_ctx *ctx = data;
+ struct grub_gpt_partentry gptdata;
+ grub_partition_t p2;
+
+ p2 = disk->partition;
+ disk->partition = p->parent;
+ if (grub_disk_read (disk, p->offset, p->index,
+ sizeof (gptdata), &gptdata))
+ {
+ disk->partition = p2;
+ return 0;
+ }
+ disk->partition = p2;
+
+ /* If there's an embed region, it is in a dedicated partition. */
+ if (! grub_memcmp (&gptdata.type, &grub_gpt_partition_type_bios_boot, 16))
+ {
+ ctx->start = p->start;
+ ctx->len = p->len;
+ return 1;
+ }
+
+ return 0;
+}
+
+static grub_err_t
+gpt_partition_map_embed (struct grub_disk *disk, unsigned int *nsectors,
+ unsigned int max_nsectors,
+ grub_embed_type_t embed_type,
+ grub_disk_addr_t **sectors)
+{
+ struct gpt_partition_map_embed_ctx ctx = {
+ .start = 0,
+ .len = 0
+ };
+ unsigned i;
+ grub_err_t err;
+
+ if (embed_type != GRUB_EMBED_PCBIOS)
+ return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
+ "GPT currently supports only PC-BIOS embedding");
+
+ err = grub_gpt_partition_map_iterate (disk, find_usable_region, &ctx);
+ if (err)
+ return err;
+
+ if (ctx.len == 0)
+ return grub_error (GRUB_ERR_FILE_NOT_FOUND,
+ N_("this GPT partition label contains no BIOS Boot Partition;"
+ " embedding won't be possible"));
+
+ if (ctx.len < *nsectors)
+ return grub_error (GRUB_ERR_OUT_OF_RANGE,
+ N_("your BIOS Boot Partition is too small;"
+ " embedding won't be possible"));
+
+ *nsectors = ctx.len;
+ if (*nsectors > max_nsectors)
+ *nsectors = max_nsectors;
+ *sectors = grub_malloc (*nsectors * sizeof (**sectors));
+ if (!*sectors)
+ return grub_errno;
+ for (i = 0; i < *nsectors; i++)
+ (*sectors)[i] = ctx.start + i;
+
+ return GRUB_ERR_NONE;
+}
+#endif
+
+\f
+/* Partition map type. */
+static struct grub_partition_map grub_gpt_partition_map =
+ {
+ .name = "gpt",
+ .iterate = grub_gpt_partition_map_iterate,
+#ifdef GRUB_UTIL
+ .embed = gpt_partition_map_embed
+#endif
+ };
+
+GRUB_MOD_INIT(part_gpt)
+{
+ grub_partition_map_register (&grub_gpt_partition_map);
+}
+
+GRUB_MOD_FINI(part_gpt)
+{
+ grub_partition_map_unregister (&grub_gpt_partition_map);
+}
projects / Ventoy.git / commitdiff