/*

 * Copyright (C) 2009 Corentin Chary <corentincj@iksaif.net>

 *

 * This file may be redistributed under the terms of the

 * GNU Lesser General Public License.

 */

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <string.h>

#include <stdint.h>

#include "superblocks.h"

#include "crc32.h"

/*

 * struct ubifs_ch - common header node.

 * @magic: UBIFS node magic number (%UBIFS_NODE_MAGIC)

 * @crc: CRC-32 checksum of the node header

 * @sqnum: sequence number

 * @len: full node length

 * @node_type: node type

 * @group_type: node group type

 * @padding: reserved for future, zeroes

 *

 * Every UBIFS node starts with this common part. If the node has a key, the

 * key always goes next.

 */

struct ubifs_ch {

  uint32_t magic;

  uint32_t crc;

  uint64_t sqnum;

  uint32_t len;

  uint8_t node_type;

  uint8_t group_type;

  uint8_t padding[2];

} __attribute__ ((packed));

/*

 * struct ubifs_sb_node - superblock node.

 * @ch: common header

 * @padding: reserved for future, zeroes

 * @key_hash: type of hash function used in keys

 * @key_fmt: format of the key

 * @flags: file-system flags (%UBIFS_FLG_BIGLPT, etc)

 * @min_io_size: minimal input/output unit size

 * @leb_size: logical eraseblock size in bytes

 * @leb_cnt: count of LEBs used by file-system

 * @max_leb_cnt: maximum count of LEBs used by file-system

 * @max_bud_bytes: maximum amount of data stored in buds

 * @log_lebs: log size in logical eraseblocks

 * @lpt_lebs: number of LEBs used for lprops table

 * @orph_lebs: number of LEBs used for recording orphans

 * @jhead_cnt: count of journal heads

 * @fanout: tree fanout (max. number of links per indexing node)

 * @lsave_cnt: number of LEB numbers in LPT's save table

 * @fmt_version: UBIFS on-flash format version

 * @default_compr: default compression algorithm (%UBIFS_COMPR_LZO, etc)

 * @padding1: reserved for future, zeroes

 * @rp_uid: reserve pool UID

 * @rp_gid: reserve pool GID

 * @rp_size: size of the reserved pool in bytes

 * @padding2: reserved for future, zeroes

 * @time_gran: time granularity in nanoseconds

 * @uuid: UUID generated when the file system image was created

 * @ro_compat_version: UBIFS R/O compatibility version

 */

struct ubifs_sb_node {

  struct ubifs_ch ch;

  uint8_t padding[2];

  uint8_t key_hash;

  uint8_t key_fmt;

  uint32_t flags;

  uint32_t min_io_size;

  uint32_t leb_size;

  uint32_t leb_cnt;

  uint32_t max_leb_cnt;

  uint64_t max_bud_bytes;

  uint32_t log_lebs;

  uint32_t lpt_lebs;

  uint32_t orph_lebs;

  uint32_t jhead_cnt;

  uint32_t fanout;

  uint32_t lsave_cnt;

  uint32_t fmt_version;

  uint16_t default_compr;

  uint8_t padding1[2];

  uint32_t rp_uid;

  uint32_t rp_gid;

  uint64_t rp_size;

  uint32_t time_gran;

  uint8_t uuid[16];

  uint32_t ro_compat_version;

  uint8_t padding2[3968];

} __attribute__ ((packed));

static int ubifs_verify_csum(blkid_probe pr, const struct ubifs_sb_node *sb)

{

  size_t csummed_offset = offsetof(struct ubifs_ch, sqnum);

  uint32_t crc = ul_crc32(~0LL,

      (unsigned char *) sb + csummed_offset,

      sizeof(*sb) - csummed_offset);

  return blkid_probe_verify_csum(pr, crc, le32_to_cpu(sb->ch.crc));

}

static int probe_ubifs(blkid_probe pr, const struct blkid_idmag *mag)

{

  const struct ubifs_sb_node *sb;

  sb = blkid_probe_get_sb(pr, mag, struct ubifs_sb_node);

  if (!sb)

    return errno ? -errno : 1;

  if (!ubifs_verify_csum(pr, sb))

    return 1;

  blkid_probe_set_uuid(pr, sb->uuid);

  blkid_probe_sprintf_version(pr, "w%dr%d",

      le32_to_cpu(sb->fmt_version),

      le32_to_cpu(sb->ro_compat_version));

  blkid_probe_set_fssize(pr,

      (uint64_t) le32_to_cpu(sb->leb_size)

      * le32_to_cpu(sb->leb_cnt));

  return 0;

}

const struct blkid_idinfo ubifs_idinfo =

{

  .name   = "ubifs",

  .usage    = BLKID_USAGE_FILESYSTEM,

  .probefunc  = probe_ubifs,

  .magics   =

  {

    { .magic = "\x31\x18\x10\x06", .len = 4 },

    { NULL }

  }

};