systemd-stable/extras/volume_id/lib/linux_raid.c

/*
 * volume_id - reads filesystem label and uuid
 *
 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
 *
 * This program 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 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <byteswap.h>

#include "libvolume_id.h"
#include "libvolume_id-private.h"

struct mdp0_super_block {
	uint32_t	md_magic;
	uint32_t	major_version;
	uint32_t	minor_version;
	uint32_t	patch_version;
	uint32_t	gvalid_words;
	uint32_t	set_uuid0;
	uint32_t	ctime;
	uint32_t	level;
	uint32_t	size;
	uint32_t	nr_disks;
	uint32_t	raid_disks;
	uint32_t	md_minor;
	uint32_t	not_persistent;
	uint32_t	set_uuid1;
	uint32_t	set_uuid2;
	uint32_t	set_uuid3;
} PACKED;

struct mdp1_super_block {
	uint32_t	magic;
	uint32_t	major_version;
	uint32_t	feature_map;
	uint32_t	pad0;
	uint8_t		set_uuid[16];
	uint8_t		set_name[32];
} PACKED;

#define MD_RESERVED_BYTES		0x10000
#define MD_SB_MAGIC			0xa92b4efc

static int volume_id_probe_linux_raid0(struct volume_id *id, uint64_t off, uint64_t size)
{
	const uint8_t *buf;
	struct mdp0_super_block *mdp0;
	union {
		uint32_t ints[4];
		uint8_t bytes[16];
	} uuid;

	info("probing at offset 0x%" PRIx64 ", size 0x%" PRIx64 "\n", off, size);
	if (size < 0x10000)
		return -1;

	buf = volume_id_get_buffer(id, off, 0x800);
	if (buf == NULL)
		return -1;
	mdp0 = (struct mdp0_super_block *) buf;

	if (le32_to_cpu(mdp0->md_magic) == MD_SB_MAGIC) {
		uuid.ints[0] = bswap_32(mdp0->set_uuid0);
		if (le32_to_cpu(mdp0->minor_version >= 90)) {
			uuid.ints[1] = bswap_32(mdp0->set_uuid1);
			uuid.ints[2] = bswap_32(mdp0->set_uuid2);
			uuid.ints[3] = bswap_32(mdp0->set_uuid3);
		} else {
			uuid.ints[1] = 0;
			uuid.ints[2] = 0;
			uuid.ints[3] = 0;
		}
		volume_id_set_uuid(id, uuid.bytes, 0, UUID_MD);
		snprintf(id->type_version, sizeof(id->type_version)-1, "%u.%u.%u",
			 le32_to_cpu(mdp0->major_version),
			 le32_to_cpu(mdp0->minor_version),
			 le32_to_cpu(mdp0->patch_version));
	} else if (be32_to_cpu(mdp0->md_magic) == MD_SB_MAGIC) {
		uuid.ints[0] = mdp0->set_uuid0;
		if (be32_to_cpu(mdp0->minor_version >= 90)) {
			uuid.ints[1] = mdp0->set_uuid1;
			uuid.ints[2] = mdp0->set_uuid2;
			uuid.ints[3] = mdp0->set_uuid3;
		} else {
			uuid.ints[1] = 0;
			uuid.ints[2] = 0;
			uuid.ints[3] = 0;
		}
		volume_id_set_uuid(id, uuid.bytes, 0, UUID_MD);
		snprintf(id->type_version, sizeof(id->type_version)-1, "%u.%u.%u",
			 be32_to_cpu(mdp0->major_version),
			 be32_to_cpu(mdp0->minor_version),
			 be32_to_cpu(mdp0->patch_version));
	} else
		return -1;

	volume_id_set_usage(id, VOLUME_ID_RAID);
	id->type = "linux_raid_member";
	return 0;
}

static int volume_id_probe_linux_raid1(struct volume_id *id, uint64_t off, uint64_t size)
{
	const uint8_t *buf;
	struct mdp1_super_block *mdp1;

	info("probing at offset 0x%" PRIx64 ", size 0x%" PRIx64 "\n", off, size);

	buf = volume_id_get_buffer(id, off, 0x800);
	if (buf == NULL)
		return -1;
	mdp1 = (struct mdp1_super_block *) buf;

	if (le32_to_cpu(mdp1->magic) != MD_SB_MAGIC)
		return -1;

	if (le32_to_cpu(mdp1->major_version) != 1)
		return -1;

	volume_id_set_uuid(id, mdp1->set_uuid, 0, UUID_MD);
	volume_id_set_label_raw(id, mdp1->set_name, 32);
	volume_id_set_label_string(id, mdp1->set_name, 32);
	volume_id_set_usage(id, VOLUME_ID_RAID);
	id->type = "linux_raid_member";
	return 0;
}

int volume_id_probe_linux_raid(struct volume_id *id, uint64_t off, uint64_t size)
{
	uint64_t sboff;

	if (size > MD_RESERVED_BYTES) {
		/* version 0 at the end of the device */
		sboff = (size & ~(MD_RESERVED_BYTES - 1)) - MD_RESERVED_BYTES;
		if (volume_id_probe_linux_raid0(id, off + sboff, size) == 0)
			return 0;

		/* version 1.0 at the end of the device */
		sboff = (size & ~(0x1000 - 1)) - 0x2000;
		if (volume_id_probe_linux_raid1(id, off + sboff, size) == 0) {
			strcpy(id->type_version, "1.0");
			return 0;
		}
	}

	/* version 1.1 at the start of the device */
	if (volume_id_probe_linux_raid1(id, off, size) == 0) {
		strcpy(id->type_version, "1.1");
		return 0;
	}

	/* version 1.2 at 4k offset from the start */
	if (volume_id_probe_linux_raid1(id, off + 0x1000, size) == 0) {
		strcpy(id->type_version, "1.2");
		return 0;
	}

	return -1;
}