source: MondoRescue/branches/3.3/mindi-busybox/util-linux/fdisk_gpt.c@ 3621

#if ENABLE_FEATURE_GPT_LABEL
/*
 * Copyright (C) 2010 Kevin Cernekee <cernekee@gmail.com>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */

#define GPT_MAGIC 0x5452415020494645ULL
enum {
    LEGACY_GPT_TYPE = 0xee,
    GPT_MAX_PARTS   = 256,
    GPT_MAX_PART_ENTRY_LEN = 4096,
    GUID_LEN        = 16,
};

typedef struct {
    uint64_t magic;
    uint32_t revision;
    uint32_t hdr_size;
    uint32_t hdr_crc32;
    uint32_t reserved;
    uint64_t current_lba;
    uint64_t backup_lba;
    uint64_t first_usable_lba;
    uint64_t last_usable_lba;
    uint8_t  disk_guid[GUID_LEN];
    uint64_t first_part_lba;
    uint32_t n_parts;
    uint32_t part_entry_len;
    uint32_t part_array_crc32;
} gpt_header;

typedef struct {
    uint8_t  type_guid[GUID_LEN];
    uint8_t  part_guid[GUID_LEN];
    uint64_t lba_start;
    uint64_t lba_end;
    uint64_t flags;
    uint16_t name[36];
} gpt_partition;

static gpt_header *gpt_hdr;

static char *part_array;
static unsigned int n_parts;
static unsigned int part_array_len;
static unsigned int part_entry_len;

static inline gpt_partition *
gpt_part(int i)
{
    if (i >= n_parts) {
        return NULL;
    }
    return (gpt_partition *)&part_array[i * part_entry_len];
}

static uint32_t
gpt_crc32(void *buf, int len)
{
    return ~crc32_block_endian0(0xffffffff, buf, len, global_crc32_table);
}

static void
gpt_print_guid(uint8_t *buf)
{
    printf(
        "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
        buf[3], buf[2], buf[1], buf[0],
        buf[5], buf[4],
        buf[7], buf[6],
        buf[8], buf[9],
        buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]);
}

/* TODO: real unicode support */
static void
gpt_print_wide(uint16_t *s, int max_len)
{
    int i = 0;

    while (i < max_len) {
        if (*s == 0)
            return;
        fputc(*s, stdout);
        s++;
    }
}

static void
gpt_list_table(int xtra UNUSED_PARAM)
{
    int i;
    char numstr6[6];

    smart_ulltoa5(total_number_of_sectors * sector_size, numstr6, " KMGTPEZY")[0] = '\0';
    printf("Disk %s: %llu sectors, %s\n", disk_device,
        (unsigned long long)total_number_of_sectors,
        numstr6);
    printf("Logical sector size: %u\n", sector_size);
    printf("Disk identifier (GUID): ");
    gpt_print_guid(gpt_hdr->disk_guid);
    printf("\nPartition table holds up to %u entries\n",
        (int)SWAP_LE32(gpt_hdr->n_parts));
    printf("First usable sector is %llu, last usable sector is %llu\n\n",
        (unsigned long long)SWAP_LE64(gpt_hdr->first_usable_lba),
        (unsigned long long)SWAP_LE64(gpt_hdr->last_usable_lba));

    puts("Number  Start (sector)    End (sector)  Size       Code  Name");
    for (i = 0; i < n_parts; i++) {
        gpt_partition *p = gpt_part(i);
        if (p->lba_start) {
            smart_ulltoa5((1 + SWAP_LE64(p->lba_end) - SWAP_LE64(p->lba_start)) * sector_size,
                numstr6, " KMGTPEZY")[0] = '\0';
            printf("%4u %15llu %15llu %11s   %04x  ",
                i + 1,
                (unsigned long long)SWAP_LE64(p->lba_start),
                (unsigned long long)SWAP_LE64(p->lba_end),
                numstr6,
                0x0700 /* FIXME */);
            gpt_print_wide(p->name, 18);
            bb_putchar('\n');
        }
    }
}

static int
check_gpt_label(void)
{
    struct partition *first = pt_offset(MBRbuffer, 0);
    struct pte pe;
    uint32_t crc;

    /* LBA 0 contains the legacy MBR */

    if (!valid_part_table_flag(MBRbuffer)
     || first->sys_ind != LEGACY_GPT_TYPE
    ) {
        current_label_type = 0;
        return 0;
    }

    /* LBA 1 contains the GPT header */

    read_pte(&pe, 1);
    gpt_hdr = (void *)pe.sectorbuffer;

    if (gpt_hdr->magic != SWAP_LE64(GPT_MAGIC)) {
        current_label_type = 0;
        return 0;
    }

    if (!global_crc32_table) {
        global_crc32_table = crc32_filltable(NULL, 0);
    }

    crc = SWAP_LE32(gpt_hdr->hdr_crc32);
    gpt_hdr->hdr_crc32 = 0;
    if (gpt_crc32(gpt_hdr, SWAP_LE32(gpt_hdr->hdr_size)) != crc) {
        /* FIXME: read the backup table */
        puts("\nwarning: GPT header CRC is invalid\n");
    }

    n_parts = SWAP_LE32(gpt_hdr->n_parts);
    part_entry_len = SWAP_LE32(gpt_hdr->part_entry_len);
    if (n_parts > GPT_MAX_PARTS
     || part_entry_len > GPT_MAX_PART_ENTRY_LEN
     || SWAP_LE32(gpt_hdr->hdr_size) > sector_size
    ) {
        puts("\nwarning: unable to parse GPT disklabel\n");
        current_label_type = 0;
        return 0;
    }

    part_array_len = n_parts * part_entry_len;
    part_array = xmalloc(part_array_len);
    seek_sector(SWAP_LE64(gpt_hdr->first_part_lba));
    if (full_read(dev_fd, part_array, part_array_len) != part_array_len) {
        fdisk_fatal(unable_to_read);
    }

    if (gpt_crc32(part_array, part_array_len) != gpt_hdr->part_array_crc32) {
        /* FIXME: read the backup table */
        puts("\nwarning: GPT array CRC is invalid\n");
    }

    puts("Found valid GPT with protective MBR; using GPT\n");

    current_label_type = LABEL_GPT;
    return 1;
}

#endif /* GPT_LABEL */