1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2005 Stanislav Sedov
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include <sys/param.h>
33#include <sys/systm.h>
34#include <sys/kernel.h>
35#include <sys/malloc.h>
36
37#include <geom/geom.h>
38#include <geom/geom_dbg.h>
39#include <geom/label/g_label.h>
40
41#define EXT2FS_SB_OFFSET	1024
42#define EXT2_SUPER_MAGIC	0xef53
43#define EXT2_DYNAMIC_REV	1
44
45typedef 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
54static void
55g_label_ext2fs_taste(struct g_consumer *cp, char *label, size_t size)
56{
57	struct g_provider *pp;
58	e2sb_t *fs;
59	char *s_volume_name;
60
61	g_topology_assert_not();
62	pp = cp->provider;
63	label[0] = '\0';
64
65	if ((EXT2FS_SB_OFFSET % pp->sectorsize) != 0)
66		return;
67
68	fs = (e2sb_t *)g_read_data(cp, EXT2FS_SB_OFFSET, pp->sectorsize, NULL);
69	if (fs == NULL)
70		return;
71
72	/* Check for magic and versio n*/
73	if (fs->s_magic == EXT2_SUPER_MAGIC &&
74	    fs->s_rev_level == EXT2_DYNAMIC_REV) {
75		G_LABEL_DEBUG(1, "ext2fs file system detected on %s.",
76		    pp->name);
77	} else {
78		goto exit_free;
79	}
80
81	s_volume_name = fs->s_volume_name;
82	/* Terminate label */
83	s_volume_name[sizeof(fs->s_volume_name) - 1] = '\0';
84
85	if (s_volume_name[0] == '/')
86		s_volume_name += 1;
87
88	/* Check for volume label */
89	if (s_volume_name[0] == '\0')
90		goto exit_free;
91
92	strlcpy(label, s_volume_name, size);
93
94exit_free:
95	g_free(fs);
96}
97
98struct g_label_desc g_label_ext2fs = {
99	.ld_taste = g_label_ext2fs_taste,
100	.ld_dirprefix = "ext2fs/",
101	.ld_enabled = 1
102};
103
104G_LABEL_INIT(ext2fs, g_label_ext2fs, "Create device nodes for EXT2FS volumes");
105