libblkid/src/superblocks/sysv.c

   1 /*
   2  * Copyright (C) 2008 Karel Zak <kzak@redhat.com>
   3  *
   4  * This is written from scratch according to Linux kernel fs/sysv/super.c file.
   5  * It seems that sysv probing code in libvolume_id and also in the original
   6  * blkid is useless.
   7  *
   8  * This file may be redistributed under the terms of the
   9  * GNU Lesser General Public License.
  10  */
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <unistd.h>
  14 #include <stdint.h>
  15 #include <stddef.h>
  16
  17 #include "superblocks.h"
  18
  19 #define XENIX_NICINOD                           100
  20 #define XENIX_NICFREE                           100
  21
  22 struct xenix_super_block {
  23         uint16_t        s_isize;
  24         uint32_t        s_fsize;
  25         uint16_t        s_nfree;
  26         uint32_t        s_free[XENIX_NICFREE];
  27         uint16_t        s_ninode;
  28         uint16_t        s_inode[XENIX_NICINOD];
  29         uint8_t         s_flock;
  30         uint8_t         s_ilock;
  31         uint8_t         s_fmod;
  32         uint8_t         s_ronly;
  33         uint32_t        s_time;
  34         uint32_t        s_tfree;
  35         uint16_t        s_tinode;
  36         uint16_t        s_dinfo[4];
  37         uint8_t         s_fname[6];
  38         uint8_t         s_fpack[6];
  39         uint8_t         s_clean;
  40         uint8_t         s_fill[371];
  41         uint32_t        s_magic;
  42         uint32_t        s_type;
  43 } __attribute__((packed));
  44
  45
  46 #define SYSV_NICINOD                    100
  47 #define SYSV_NICFREE                    50
  48
  49 struct sysv_super_block
  50 {
  51         uint16_t        s_isize;
  52         uint16_t        s_pad0;
  53         uint32_t        s_fsize;
  54         uint16_t        s_nfree;
  55         uint16_t        s_pad1;
  56         uint32_t        s_free[SYSV_NICFREE];
  57         uint16_t        s_ninode;
  58         uint16_t        s_pad2;
  59         uint16_t        s_inode[SYSV_NICINOD];
  60         uint8_t         s_flock;
  61         uint8_t         s_ilock;
  62         uint8_t         s_fmod;
  63         uint8_t         s_ronly;
  64         uint32_t        s_time;
  65         uint16_t        s_dinfo[4];
  66         uint32_t        s_tfree;
  67         uint16_t        s_tinode;
  68         uint16_t        s_pad3;
  69         uint8_t         s_fname[6];
  70         uint8_t         s_fpack[6];
  71         uint32_t        s_fill[12];
  72         uint32_t        s_state;
  73         uint32_t        s_magic;
  74         uint32_t        s_type;
  75 };
  76
  77 static int probe_xenix(blkid_probe pr, const struct blkid_idmag *mag)
  78 {
  79         struct xenix_super_block *sb;
  80
  81         sb = blkid_probe_get_sb(pr, mag, struct xenix_super_block);
  82         if (!sb)
  83                 return errno ? -errno : 1;
  84         blkid_probe_set_label(pr, sb->s_fname, sizeof(sb->s_fname));
  85         return 0;
  86 }
  87
  88 #define SYSV_BLOCK_SIZE 1024
  89
  90 /* Note that we don't probe for Coherent FS, this FS does not have
  91  * magic string. (It requires to probe fname/fpack field..)
  92  */
  93 static int probe_sysv(blkid_probe pr,
  94                 const struct blkid_idmag *mag __attribute__((__unused__)))
  95 {
  96         struct sysv_super_block *sb;
  97         int blocks[] = {0, 9, 15, 18};
  98         size_t i;
  99
 100         for (i = 0; i < ARRAY_SIZE(blocks); i++) {
 101                 int off = blocks[i] * SYSV_BLOCK_SIZE + SYSV_BLOCK_SIZE/2;
 102
 103                 sb = (struct sysv_super_block *)
 104                         blkid_probe_get_buffer(pr,
 105                                         off,
 106                                         sizeof(struct sysv_super_block));
 107                 if (!sb)
 108                         return errno ? -errno : 1;
 109
 110                 if (sb->s_magic == cpu_to_le32(0xfd187e20) ||
 111                     sb->s_magic == cpu_to_be32(0xfd187e20)) {
 112
 113                         if (blkid_probe_set_label(pr, sb->s_fname,
 114                                                 sizeof(sb->s_fname)))
 115                                 return 1;
 116
 117                         if (blkid_probe_set_magic(pr,
 118                                         off + offsetof(struct sysv_super_block,
 119                                                                 s_magic),
 120                                         sizeof(sb->s_magic),
 121                                         (unsigned char *) &sb->s_magic))
 122                                 return 1;
 123
 124                         return 0;
 125                 }
 126         }
 127         return 1;
 128 }
 129
 130 const struct blkid_idinfo xenix_idinfo =
 131 {
 132         .name           = "xenix",
 133         .usage          = BLKID_USAGE_FILESYSTEM,
 134         .probefunc      = probe_xenix,
 135         .magics         =
 136         {
 137                 { .magic = "\x2b\x55\x44", .len = 3, .kboff = 1, .sboff = 0x400 },
 138                 { .magic = "\x44\x55\x2b", .len = 3, .kboff = 1, .sboff = 0x400 },
 139                 { NULL }
 140         }
 141 };
 142
 143 const struct blkid_idinfo sysv_idinfo =
 144 {
 145         .name           = "sysv",
 146         .usage          = BLKID_USAGE_FILESYSTEM,
 147         .probefunc      = probe_sysv,
 148
 149         /* SYSV is BE and LE and superblock could be on four positions. It's
 150          * simpler to probe for the magic string by .probefunc().
 151          */
 152         .magics         = BLKID_NONE_MAGIC
 153 };
 154