1  /*
       2   * Copyright (C) 2020 Western Digital Corporation or its affiliates.
       3   *
       4   * This file may be redistributed under the terms of the
       5   * GNU Lesser General Public License
       6   */
       7  #include <stddef.h>
       8  #include <string.h>
       9  
      10  #include "superblocks.h"
      11  #include "crc32.h"
      12  
      13  #define ZONEFS_MAGIC		"SFOZ" /* 0x5a4f4653 'Z' 'O' 'F' 'S' */
      14  #define ZONEFS_MAGIC_SIZE	4
      15  #define ZONEFS_MAGIC_OFST	0
      16  #define ZONEFS_UUID_SIZE	16
      17  #define ZONEFS_LABEL_SIZE	32
      18  #define ZONEFS_SB_OFST		0
      19  
      20  #define ZONEFS_BLOCK_SIZE	4096U
      21  
      22  /* All in little-endian */
      23  struct zonefs_super {
      24  
      25  	/* Magic number */
      26  	int32_t		s_magic;
      27  
      28  	/* Checksum */
      29  	int32_t		s_crc;
      30  
      31  	/* Volume label */
      32  	char		s_label[ZONEFS_LABEL_SIZE];
      33  
      34  	/* 128-bit uuid */
      35  	uint8_t		s_uuid[ZONEFS_UUID_SIZE];
      36  
      37  	/* Features */
      38  	int64_t		s_features;
      39  
      40  	/* UID/GID to use for files */
      41  	int32_t		s_uid;
      42  	int32_t		s_gid;
      43  
      44  	/* File permissions */
      45  	int32_t		s_perm;
      46  
      47  	/* Padding to 4096 bytes */
      48  	uint8_t		s_reserved[4020];
      49  
      50  } __attribute__ ((packed));
      51  
      52  static int zonefs_verify_csum(blkid_probe pr, struct zonefs_super *sb)
      53  {
      54  	uint32_t expected = le32_to_cpu(sb->s_crc);
      55  	sb->s_crc = 0;
      56  	uint32_t crc = ul_crc32(~0LL, (unsigned char *) sb, sizeof(*sb));
      57  	return blkid_probe_verify_csum(pr, crc, expected);
      58  }
      59  
      60  static int probe_zonefs(blkid_probe pr,
      61  		const struct blkid_idmag *mag  __attribute__((__unused__)))
      62  {
      63  	struct zonefs_super *sb;
      64  
      65  	sb = (struct zonefs_super *)
      66  		blkid_probe_get_buffer(pr, ZONEFS_SB_OFST,
      67  				       sizeof(struct zonefs_super));
      68  	if (!sb)
      69  		return errno ? -errno : 1;
      70  
      71  	if (!zonefs_verify_csum(pr, sb))
      72  		return 1;
      73  
      74  	if (sb->s_label[0])
      75  		blkid_probe_set_label(pr, (unsigned char *) sb->s_label,
      76  				      sizeof(sb->s_label));
      77  
      78  	blkid_probe_set_uuid(pr, sb->s_uuid);
      79  	blkid_probe_set_fsblocksize(pr, ZONEFS_BLOCK_SIZE);
      80  	blkid_probe_set_block_size(pr, ZONEFS_BLOCK_SIZE);
      81  
      82  	return 0;
      83  }
      84  
      85  const struct blkid_idinfo zonefs_idinfo =
      86  {
      87  	.name           = "zonefs",
      88  	.usage          = BLKID_USAGE_FILESYSTEM,
      89  	.probefunc      = probe_zonefs,
      90  	.magics         =
      91          {
      92  		{
      93  			.magic = (char *)ZONEFS_MAGIC,
      94  			.len = ZONEFS_MAGIC_SIZE,
      95  			.kboff = ZONEFS_SB_OFST,
      96  			.sboff = ZONEFS_MAGIC_OFST,
      97  		},
      98  		{ NULL }
      99  	}
     100  };