1/*
2 * Copyright (c) 2017 Conrad Meyer <cem@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 AUTHOR 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 AUTHOR 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: stable/11/usr.sbin/fstyp/exfat.c 316470 2017-04-03 21:04:14Z trasz $");
29
30#include <stdint.h>
31#include <stdio.h>
32#include <stdlib.h>
33#include <string.h>
34
35#include "fstyp.h"
36
37struct exfat_vbr {
38	char		ev_jmp[3];
39	char		ev_fsname[8];
40	char		ev_zeros[53];
41	uint64_t	ev_part_offset;
42	uint64_t	ev_vol_length;
43	uint32_t	ev_fat_offset;
44	uint32_t	ev_fat_length;
45	uint32_t	ev_cluster_offset;
46	uint32_t	ev_cluster_count;
47	uint32_t	ev_rootdir_cluster;
48	uint32_t	ev_vol_serial;
49	uint16_t	ev_fs_revision;
50	uint16_t	ev_vol_flags;
51	uint8_t		ev_log_bytes_per_sect;
52	uint8_t		ev_log_sect_per_clust;
53	uint8_t		ev_num_fats;
54	uint8_t		ev_drive_sel;
55	uint8_t		ev_percent_used;
56} __packed;
57
58int
59fstyp_exfat(FILE *fp, char *label, size_t size)
60{
61	struct exfat_vbr *ev;
62
63	ev = (struct exfat_vbr *)read_buf(fp, 0, 512);
64	if (ev == NULL || strncmp(ev->ev_fsname, "EXFAT   ", 8) != 0)
65		goto fail;
66
67	/*
68	 * Reading the volume label requires walking the root directory to look
69	 * for a special label file.  Left as an exercise for the reader.
70	 */
71	free(ev);
72	return (0);
73
74fail:
75	free(ev);
76	return (1);
77}
78