usr.sbin/fstyp/ext2fs.c

   1 /*-
   2  * Copyright (c) 2016 The DragonFly Project
   3  * Copyright (c) 2005 Stanislav Sedov
   4  * Copyright (c) 2014 The FreeBSD Foundation
   5  * All rights reserved.
   6  *
   7  * This software was developed by Edward Tomasz Napierala under sponsorship
   8  * from the FreeBSD Foundation.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <stdio.h>
  33 #include <stdint.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36
  37 #include "fstyp.h"
  38
  39 #define EXT2FS_SB_OFFSET        1024
  40 #define EXT2_SUPER_MAGIC        0xef53
  41 #define EXT2_DYNAMIC_REV        1
  42
  43 typedef struct e2sb {
  44         uint8_t         fake1[56];
  45         uint16_t        s_magic;
  46         uint8_t         fake2[18];
  47         uint32_t        s_rev_level;
  48         uint8_t         fake3[40];
  49         char            s_volume_name[16];
  50 } e2sb_t;
  51
  52 int
  53 fstyp_ext2fs(FILE *fp, char *label, size_t size)
  54 {
  55         e2sb_t *fs;
  56         char *s_volume_name;
  57
  58         fs = (e2sb_t *)read_buf(fp, EXT2FS_SB_OFFSET, 512);
  59         if (fs == NULL)
  60                 return (1);
  61
  62         /* Check for magic and versio n*/
  63         if (fs->s_magic == EXT2_SUPER_MAGIC &&
  64             fs->s_rev_level == EXT2_DYNAMIC_REV) {
  65                 //G_LABEL_DEBUG(1, "ext2fs file system detected on %s.",
  66                 //    pp->name);
  67         } else {
  68                 free(fs);
  69                 return (1);
  70         }
  71
  72         s_volume_name = fs->s_volume_name;
  73         /* Terminate label */
  74         s_volume_name[sizeof(fs->s_volume_name) - 1] = '\0';
  75
  76         if (s_volume_name[0] == '/')
  77                 s_volume_name += 1;
  78
  79         strlcpy(label, s_volume_name, size);
  80         free(fs);
  81
  82         return (0);
  83 }