libblkid-tiny/squashfs.c

   1 /*
   2  * Copyright (C) 2008 Karel Zak <kzak@redhat.com>
   3  *
   4  * Inspired by libvolume_id by
   5  *     Kay Sievers <kay.sievers@vrfy.org>
   6  *
   7  * This file may be redistributed under the terms of the
   8  * GNU Lesser General Public License.
   9  */
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13 #include <string.h>
  14 #include <stdint.h>
  15
  16 #include "bitops.h"     /* swab16() */
  17 #include "superblocks.h"
  18
  19 #include <libubox/md5.h>
  20
  21 struct squashfs_super_block {
  22         uint32_t s_magic;
  23         uint32_t inodes;
  24         uint32_t mkfs_time;
  25         uint32_t block_size;
  26         uint32_t fragments;
  27         uint16_t compression;
  28         uint16_t block_log;
  29         uint16_t flags;
  30         uint16_t no_ids;
  31         uint16_t s_major;
  32         uint16_t s_minor;
  33         uint64_t root_inode;
  34         uint64_t bytes_used;
  35         uint64_t id_table_start;
  36         uint64_t xattr_id_table_start;
  37         uint64_t inode_table_start;
  38         uint64_t directory_table_start;
  39         uint64_t fragment_table_start;
  40         uint64_t lookup_table_start;
  41 } __attribute__((packed));
  42
  43 static int probe_squashfs(blkid_probe pr, const struct blkid_idmag *mag)
  44 {
  45         md5_ctx_t ctx = { 0 };
  46         uint32_t md5[4];
  47         struct squashfs_super_block *sq;
  48
  49         sq = blkid_probe_get_sb(pr, mag, struct squashfs_super_block);
  50         if (!sq)
  51                 return -1;
  52
  53         if (strcmp(mag->magic, "sqsh") == 0 ||
  54             strcmp(mag->magic, "qshs") == 0)
  55                 blkid_probe_sprintf_version(pr, "%u.%u",
  56                                 sq->s_major,
  57                                 sq->s_minor);
  58         else
  59                 blkid_probe_sprintf_version(pr, "%u.%u",
  60                                 swab16(sq->s_major),
  61                                 swab16(sq->s_minor));
  62         md5_begin(&ctx);
  63         md5_hash(sq, sizeof(*sq), &ctx);
  64         md5_end(&md5, &ctx);
  65         blkid_probe_sprintf_uuid(pr, NULL, 4, "%08x-%08x-%08x-%08x",
  66                         md5[3], md5[2], md5[1], md5[0]);
  67         return 0;
  68 }
  69
  70 const struct blkid_idinfo squashfs_idinfo =
  71 {
  72         .name           = "squashfs",
  73         .usage          = BLKID_USAGE_FILESYSTEM,
  74         .probefunc      = probe_squashfs,
  75         .magics         =
  76         {
  77                 { .magic = "sqsh", .len = 4 },
  78                 { .magic = "hsqs", .len = 4 }, /* swap */
  79
  80                 /* LZMA version */
  81                 { .magic = "qshs", .len = 4 },
  82                 { .magic = "shsq", .len = 4 }, /* swap */
  83                 { NULL }
  84         }
  85 };
  86
  87