g_label_msdosfs.c revision 155174 
1/*-
2 * Copyright (c) 2004 Pawel Jakub Dawidek <pjd@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/sys/geom/label/g_label_msdosfs.c 155174 2006-02-01 12:06:01Z pjd $");
29
30#include <sys/param.h>
31#include <sys/systm.h>
32#include <sys/kernel.h>
33#include <sys/malloc.h>
34
35#include <geom/geom.h>
36#include <geom/label/g_label.h>
37
38#define G_LABEL_MSDOSFS_DIR	"msdosfs"
39
40#define	FAT12	"FAT12   "
41#define	FAT16	"FAT16   "
42#define	FAT32	"FAT32   "
43#define	VOLUME_LEN	11
44#define NO_NAME "NO NAME    "
45
46
47static void
48g_label_msdosfs_taste(struct g_consumer *cp, char *label, size_t size)
49{
50	struct g_provider *pp;
51	char *sector, *volume;
52	int i;
53
54	g_topology_assert_not();
55	pp = cp->provider;
56	label[0] = '\0';
57
58	sector = (char *)g_read_data(cp, 0, pp->sectorsize, NULL);
59	if (sector == NULL)
60		return;
61	if (strncmp(sector + 0x36, FAT12, strlen(FAT12)) == 0) {
62		G_LABEL_DEBUG(1, "MSDOS (FAT12) file system detected on %s.",
63		    pp->name);
64		volume = sector + 0x2b;
65	} else if (strncmp(sector + 0x36, FAT16, strlen(FAT16)) == 0) {
66		G_LABEL_DEBUG(1, "MSDOS (FAT16) file system detected on %s.",
67		    pp->name);
68		volume = sector + 0x2b;
69	} else if (strncmp(sector + 0x52, FAT32, strlen(FAT32)) == 0) {
70		G_LABEL_DEBUG(1, "MSDOS (FAT32) file system detected on %s.",
71		    pp->name);
72		volume = sector + 0x47;
73	} else {
74		g_free(sector);
75		return;
76	}
77	if (strncmp(volume, NO_NAME, VOLUME_LEN) == 0) {
78		g_free(sector);
79		return;
80	}
81	if (volume[0] == '\0') {
82		g_free(sector);
83		return;
84	}
85	bzero(label, size);
86	strlcpy(label, volume, MIN(size, VOLUME_LEN));
87	g_free(sector);
88	for (i = size - 1; i > 0; i--) {
89		if (label[i] == '\0')
90			continue;
91		else if (label[i] == ' ')
92			label[i] = '\0';
93		else
94			break;
95	}
96}
97
98const struct g_label_desc g_label_msdosfs = {
99	.ld_taste = g_label_msdosfs_taste,
100	.ld_dir = G_LABEL_MSDOSFS_DIR
101};
102