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/*
* Copyright (C) 2018 Tony Asleson <tasleson@redhat.com>
*
* This file may be redistributed under the terms of the
* GNU Lesser General Public License.
*/
/*
* Specification for on disk format
* https://stratis-storage.github.io/StratisSoftwareDesign.pdf
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stdint.h>
#include <inttypes.h>
#include "superblocks.h"
#include "crc32c.h"
/* Macro to avoid error in struct declaration. */
#define STRATIS_UUID_LEN 32
/* Contains 4 hyphens and trailing null byte. */
#define STRATIS_UUID_STR_LEN 37
struct stratis_sb {
uint32_t crc32;
uint8_t magic[16];
uint64_t sectors;
uint8_t reserved[4];
uint8_t pool_uuid[STRATIS_UUID_LEN];
uint8_t dev_uuid[STRATIS_UUID_LEN];
uint64_t mda_size;
uint64_t reserved_size;
uint64_t flags;
uint64_t initialization_time;
} __attribute__ ((__packed__));
#define BS 512
#define FIRST_COPY_OFFSET BS
#define SECOND_COPY_OFFSET (BS * 9)
#define SB_AREA_SIZE (BS * 16)
const char STRATIS_MAGIC[] = "!Stra0tis\x86\xff\x02^\x41rh";
#define MAGIC_LEN (sizeof(STRATIS_MAGIC) - 1)
#define _MAGIC_OFFSET (offsetof(const struct stratis_sb, magic))
#define MAGIC_OFFSET_COPY_1 (FIRST_COPY_OFFSET + _MAGIC_OFFSET)
#define MAGIC_OFFSET_COPY_2 (SECOND_COPY_OFFSET + _MAGIC_OFFSET)
static int stratis_valid_sb(const uint8_t *p)
{
const struct stratis_sb *stratis = (const struct stratis_sb *)p;
uint32_t crc = 0;
/* generate CRC from byte position 4 for length 508 == 512 byte sector */
crc = crc32c(~0L, p + sizeof(stratis->crc32),
BS - sizeof(stratis->crc32));
crc ^= ~0L;
return crc == le32_to_cpu(stratis->crc32);
}
/*
* Format UUID string representation to include hyphens given that Stratis stores
* UUIDs without hyphens in the superblock to keep the UUID length a power of 2.
*/
static void stratis_format_uuid(const unsigned char *src_uuid,
unsigned char *dst_uuid)
{
int i;
for (i = 0; i < STRATIS_UUID_LEN; i++) {
*dst_uuid++ = *src_uuid++;
if (i == 7 || i == 11 || i == 15 || i == 19)
*dst_uuid ++ = '-';
}
*dst_uuid = '\0';
}
static int probe_stratis(blkid_probe pr,
const struct blkid_idmag *mag __attribute__((__unused__)))
{
const struct stratis_sb *stratis = NULL;
const uint8_t *buf = blkid_probe_get_buffer(pr, 0, SB_AREA_SIZE);
unsigned char uuid[STRATIS_UUID_STR_LEN];
if (!buf)
return errno ? -errno : 1;
if (stratis_valid_sb(buf + FIRST_COPY_OFFSET)) {
stratis = (const struct stratis_sb *)(buf + FIRST_COPY_OFFSET);
} else {
if (!stratis_valid_sb(buf + SECOND_COPY_OFFSET))
return 1;
stratis = (const struct stratis_sb *)
(buf + SECOND_COPY_OFFSET);
}
stratis_format_uuid(stratis->dev_uuid, uuid);
blkid_probe_strncpy_uuid(pr, uuid, sizeof(uuid));
stratis_format_uuid(stratis->pool_uuid, uuid);
blkid_probe_set_value(pr, "POOL_UUID", uuid, sizeof(uuid));
blkid_probe_sprintf_value(pr, "BLOCKDEV_SECTORS", "%" PRIu64,
le64_to_cpu(stratis->sectors));
blkid_probe_sprintf_value(pr, "BLOCKDEV_INITTIME", "%" PRIu64,
le64_to_cpu(stratis->initialization_time));
return 0;
}
const struct blkid_idinfo stratis_idinfo = {
.name = "stratis",
.usage = BLKID_USAGE_RAID,
.probefunc = probe_stratis,
.minsz = SB_AREA_SIZE,
.magics = {
{ .magic = STRATIS_MAGIC, .len = MAGIC_LEN,
.sboff = MAGIC_OFFSET_COPY_1},
{ .magic = STRATIS_MAGIC, .len = MAGIC_LEN,
.sboff = MAGIC_OFFSET_COPY_2},
{ NULL }
}
};
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