xref: /freebsd/usr.sbin/fstyp/ext2fs.c (revision d4eeb02986980bf33dd56c41ceb9fc5f180c0d47)
1 /*-
2  * Copyright (c) 2005 Stanislav Sedov
3  * Copyright (c) 2014 The FreeBSD Foundation
4  * All rights reserved.
5  *
6  * This software was developed by Edward Tomasz Napierala under sponsorship
7  * from the FreeBSD Foundation.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <stdio.h>
35 #include <stdint.h>
36 #include <stdlib.h>
37 #include <string.h>
38 
39 #include "fstyp.h"
40 
41 #define EXT2FS_SB_OFFSET	1024
42 #define EXT2_SUPER_MAGIC	0xef53
43 #define EXT2_DYNAMIC_REV	1
44 
45 typedef struct e2sb {
46 	uint8_t		fake1[56];
47 	uint16_t	s_magic;
48 	uint8_t		fake2[18];
49 	uint32_t	s_rev_level;
50 	uint8_t		fake3[40];
51 	char		s_volume_name[16];
52 } e2sb_t;
53 
54 int
55 fstyp_ext2fs(FILE *fp, char *label, size_t size)
56 {
57 	e2sb_t *fs;
58 	char *s_volume_name;
59 
60 	fs = (e2sb_t *)read_buf(fp, EXT2FS_SB_OFFSET, 512);
61 	if (fs == NULL)
62 		return (1);
63 
64 	/* Check for magic and versio n*/
65 	if (fs->s_magic == EXT2_SUPER_MAGIC &&
66 	    fs->s_rev_level == EXT2_DYNAMIC_REV) {
67 		//G_LABEL_DEBUG(1, "ext2fs file system detected on %s.",
68 		//    pp->name);
69 	} else {
70 		free(fs);
71 		return (1);
72 	}
73 
74 	s_volume_name = fs->s_volume_name;
75 	/* Terminate label */
76 	s_volume_name[sizeof(fs->s_volume_name) - 1] = '\0';
77 
78 	if (s_volume_name[0] == '/')
79 		s_volume_name += 1;
80 
81 	strlcpy(label, s_volume_name, size);
82 	free(fs);
83 
84 	return (0);
85 }
86