1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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/param.h>
30 #include <sys/systm.h>
31 #include <sys/kernel.h>
32 #include <sys/malloc.h>
33
34 #include <geom/geom.h>
35 #include <geom/geom_dbg.h>
36 #include <geom/label/g_label.h>
37
38 #define EXT2FS_SB_OFFSET 1024
39 #define EXT2_SUPER_MAGIC 0xef53
40 #define EXT2_DYNAMIC_REV 1
41
42 typedef struct e2sb {
43 uint8_t fake1[56];
44 uint16_t s_magic;
45 uint8_t fake2[18];
46 uint32_t s_rev_level;
47 uint8_t fake3[40];
48 char s_volume_name[16];
49 } e2sb_t;
50
51 static void
g_label_ext2fs_taste(struct g_consumer * cp,char * label,size_t size)52 g_label_ext2fs_taste(struct g_consumer *cp, char *label, size_t size)
53 {
54 struct g_provider *pp;
55 e2sb_t *fs;
56 char *s_volume_name;
57
58 g_topology_assert_not();
59 pp = cp->provider;
60 label[0] = '\0';
61
62 KASSERT(pp->sectorsize != 0, ("Tasting a disk with 0 sectorsize"));
63 if (pp->sectorsize < sizeof(*fs))
64 return;
65 if ((EXT2FS_SB_OFFSET % pp->sectorsize) != 0)
66 return;
67
68 fs = 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
94 exit_free:
95 g_free(fs);
96 }
97
98 struct g_label_desc g_label_ext2fs = {
99 .ld_taste = g_label_ext2fs_taste,
100 .ld_dirprefix = "ext2fs/",
101 .ld_enabled = 1
102 };
103
104 G_LABEL_INIT(ext2fs, g_label_ext2fs, "Create device nodes for EXT2FS volumes");
105