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

93 lines
2.4 KiB
C

/*
* volume_id - reads filesystem label and uuid
*
* Copyright (C) 2008 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 btrfs_super_block {
uint8_t csum[32];
uint8_t fsid[16];
uint64_t bytenr;
uint64_t flags;
uint8_t magic[8];
uint64_t generation;
uint64_t root;
uint64_t chunk_root;
uint64_t log_root;
uint64_t total_bytes;
uint64_t bytes_used;
uint64_t root_dir_objectid;
uint64_t num_devices;
uint32_t sectorsize;
uint32_t nodesize;
uint32_t leafsize;
uint32_t stripesize;
uint32_t sys_chunk_array_size;
uint8_t root_level;
uint8_t chunk_root_level;
uint8_t log_root_level;
struct btrfs_dev_item {
uint64_t devid;
uint64_t total_bytes;
uint64_t bytes_used;
uint32_t io_align;
uint32_t io_width;
uint32_t sector_size;
uint64_t type;
uint32_t dev_group;
uint8_t seek_speed;
uint8_t bandwidth;
uint8_t uuid[16];
} PACKED dev_item;
uint8_t label[256];
} PACKED;
int volume_id_probe_btrfs(struct volume_id *id, uint64_t off, uint64_t size)
{
const uint8_t *buf;
struct btrfs_super_block *bfs;
info("probing at offset 0x%" PRIx64 ", size 0x%" PRIx64 "\n", off, size);
buf = volume_id_get_buffer(id, off + 0x4000, 0x200);
if (buf == NULL)
return -1;
bfs = (struct btrfs_super_block *)buf;
if (memcmp(bfs->magic, "_BBRfS_M", 8) != 0)
return -1;
volume_id_set_uuid(id, bfs->fsid, 0, UUID_DCE);
volume_id_set_label_raw(id, bfs->label, 256);
volume_id_set_label_string(id, bfs->label, 256);
volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
id->type = "btrfs";
return 0;
}