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
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 static void
55 g_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 KASSERT(pp->sectorsize != 0, ("Tasting a disk with 0 sectorsize"));
66 if (pp->sectorsize < sizeof(*fs))
67 return;
68 if ((EXT2FS_SB_OFFSET % pp->sectorsize) != 0)
69 return;
70
71 fs = g_read_data(cp, EXT2FS_SB_OFFSET, pp->sectorsize, NULL);
72 if (fs == NULL)
73 return;
74
75 /* Check for magic and versio n*/
76 if (fs->s_magic == EXT2_SUPER_MAGIC &&
77 fs->s_rev_level == EXT2_DYNAMIC_REV) {
78 G_LABEL_DEBUG(1, "ext2fs file system detected on %s.",
79 pp->name);
80 } else {
81 goto exit_free;
82 }
83
84 s_volume_name = fs->s_volume_name;
85 /* Terminate label */
86 s_volume_name[sizeof(fs->s_volume_name) - 1] = '\0';
87
88 if (s_volume_name[0] == '/')
89 s_volume_name += 1;
90
91 /* Check for volume label */
92 if (s_volume_name[0] == '\0')
93 goto exit_free;
94
95 strlcpy(label, s_volume_name, size);
96
97 exit_free:
98 g_free(fs);
99 }
100
101 struct g_label_desc g_label_ext2fs = {
102 .ld_taste = g_label_ext2fs_taste,
103 .ld_dirprefix = "ext2fs/",
104 .ld_enabled = 1
105 };
106
107 G_LABEL_INIT(ext2fs, g_label_ext2fs, "Create device nodes for EXT2FS volumes");
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