busybox/util-linux/fdisk_gpt.c

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#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 uint32_t *crc32_table;
static inline gpt_partition *
gpt_part(int i)
{
if (i >= n_parts) {
return NULL;
}
return (gpt_partition *)&part_array[i * part_entry_len];
}
/* TODO: move to libbb */
static uint32_t
gpt_crc32(void *buf, int len)
{
uint32_t crc = 0xffffffff;
for (; len > 0; len--, buf++) {
crc = crc32_table[(crc ^ *((char *)buf)) & 0xff] ^ (crc >> 8);
}
return crc ^ 0xffffffff;
}
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];
numstr6[5] = '\0';
smart_ulltoa5(total_number_of_sectors, numstr6, " KMGTPEZY");
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));
printf("Number Start (sector) End (sector) Size Code Name\n");
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),
numstr6, " KMGTPEZY");
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);
printf("\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 (!crc32_table) {
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 */