/*

 * Copyright (C) 1999 by Andries Brouwer

 * Copyright (C) 1999, 2000, 2003 by Theodore Ts'o

 * Copyright (C) 2001 by Andreas Dilger

 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>

 * Copyright (C) 2008 Karel Zak <kzak@redhat.com>

 *

 * 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 cramfs_super

{

  uint8_t   magic[4];

  uint32_t  size;

  uint32_t  flags;

  uint32_t  future;

  uint8_t   signature[16];

  struct cramfs_info

  {

    uint32_t  crc;

    uint32_t  edition;

    uint32_t  blocks;

    uint32_t  files;

  } __attribute__((packed)) info;

  uint8_t   name[16];

} __attribute__((packed));

#define CRAMFS_FLAG_FSID_VERSION_2  0x00000001  /* fsid version #2 */

static uint32_t cfs32_to_cpu(int le, uint32_t value)

{

  if (le)

    return le32_to_cpu(value);

  else

    return be32_to_cpu(value);

}

static int cramfs_verify_csum(blkid_probe pr, const struct blkid_idmag *mag,

    const struct cramfs_super *cs, int le)

{

  uint32_t crc, expected, csummed_size;

  const unsigned char *csummed;

  expected = cfs32_to_cpu(le, cs->info.crc);

  csummed_size = cfs32_to_cpu(le, cs->size);

  if (csummed_size > (1 << 16)

      || csummed_size < sizeof(struct cramfs_super))

    return 0;

  csummed = blkid_probe_get_sb_buffer(pr, mag, csummed_size);

  if (!csummed)

    return 0;

  crc = ~ul_crc32_exclude_offset(~0LL, csummed, csummed_size,

      offsetof(struct cramfs_super, info.crc),

      sizeof_member(struct cramfs_super, info.crc), 0);

  return blkid_probe_verify_csum(pr, crc, expected);

}

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

{

  const struct cramfs_super *cs;

  cs = blkid_probe_get_sb(pr, mag, struct cramfs_super);

  if (!cs)

    return errno ? -errno : 1;

  int le = mag->hint == BLKID_ENDIANNESS_LITTLE;

  int v2 = cfs32_to_cpu(le, cs->flags) & CRAMFS_FLAG_FSID_VERSION_2;

  if (v2 && !cramfs_verify_csum(pr, mag, cs, le))

    return 1;

  blkid_probe_set_label(pr, cs->name, sizeof(cs->name));

  blkid_probe_set_fssize(pr, cfs32_to_cpu(le, cs->size));

  blkid_probe_sprintf_version(pr, "%d", v2 ? 2 : 1);

  blkid_probe_set_fsendianness(pr, mag->hint);

  return 0;

}

const struct blkid_idinfo cramfs_idinfo =

{

  .name   = "cramfs",

  .usage    = BLKID_USAGE_FILESYSTEM,

  .probefunc  = probe_cramfs,

  .magics   =

  {

    { .magic = "\x45\x3d\xcd\x28", .len = 4,

      .hint = BLKID_ENDIANNESS_LITTLE },

    { .magic = "\x28\xcd\x3d\x45", .len = 4,

      .hint = BLKID_ENDIANNESS_BIG },

    { NULL }

  }

};