2 * Copyright (c) 2016 The DragonFly Project
3 * Copyright (c) 2004 Pawel Jakub Dawidek <pjd@FreeBSD.org>
4 * Copyright (c) 2006 Tobias Reifenberger
5 * Copyright (c) 2014 The FreeBSD Foundation
8 * This software was developed by Edward Tomasz Napierala under sponsorship
9 * from the FreeBSD Foundation.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 #include <sys/param.h>
41 #define LABEL_NO_NAME "NO NAME "
44 fstyp_msdosfs(FILE *fp
, char *label
, size_t size
)
46 FAT_BSBPB
*pfat_bsbpb
;
47 FAT32_BSBPB
*pfat32_bsbpb
;
49 uint8_t *sector0
, *sector
;
54 /* Load 1st sector with boot sector and boot parameter block. */
55 sector0
= (uint8_t *)read_buf(fp
, 0, 512);
59 /* Check for the FAT boot sector signature. */
60 if (sector0
[510] != 0x55 || sector0
[511] != 0xaa) {
65 * Test if this is really a FAT volume and determine the FAT type.
68 pfat_bsbpb
= (FAT_BSBPB
*)sector0
;
69 pfat32_bsbpb
= (FAT32_BSBPB
*)sector0
;
71 if (UINT16BYTES(pfat_bsbpb
->BPB_FATSz16
) != 0) {
73 * If the BPB_FATSz16 field is not zero and the string "FAT" is
74 * at the right place, this should be a FAT12 or FAT16 volume.
76 if (strncmp(pfat_bsbpb
->BS_FilSysType
, "FAT", 3) != 0) {
80 /* A volume with no name should have "NO NAME " as label. */
81 if (strncmp(pfat_bsbpb
->BS_VolLab
, LABEL_NO_NAME
,
82 sizeof(pfat_bsbpb
->BS_VolLab
)) == 0) {
85 strlcpy(label
, pfat_bsbpb
->BS_VolLab
,
86 MIN(size
, sizeof(pfat_bsbpb
->BS_VolLab
) + 1));
87 } else if (UINT32BYTES(pfat32_bsbpb
->BPB_FATSz32
) != 0) {
88 uint32_t fat_FirstDataSector
, fat_BytesPerSector
, offset
;
91 * If the BPB_FATSz32 field is not zero and the string "FAT" is
92 * at the right place, this should be a FAT32 volume.
94 if (strncmp(pfat32_bsbpb
->BS_FilSysType
, "FAT", 3) != 0) {
99 * If the volume label is not "NO NAME " we're done.
101 if (strncmp(pfat32_bsbpb
->BS_VolLab
, LABEL_NO_NAME
,
102 sizeof(pfat32_bsbpb
->BS_VolLab
)) != 0) {
103 strlcpy(label
, pfat32_bsbpb
->BS_VolLab
,
104 MIN(size
, sizeof(pfat32_bsbpb
->BS_VolLab
) + 1));
109 * If the volume label "NO NAME " is in the boot sector, the
110 * label of FAT32 volumes may be stored as a special entry in
111 * the root directory.
113 fat_FirstDataSector
=
114 UINT16BYTES(pfat32_bsbpb
->BPB_RsvdSecCnt
) +
115 (pfat32_bsbpb
->BPB_NumFATs
*
116 UINT32BYTES(pfat32_bsbpb
->BPB_FATSz32
));
117 fat_BytesPerSector
= UINT16BYTES(pfat32_bsbpb
->BPB_BytsPerSec
);
119 // fat_FirstDataSector, fat_BytesPerSector);
121 for (offset
= fat_BytesPerSector
* fat_FirstDataSector
;;
122 offset
+= fat_BytesPerSector
) {
123 sector
= (uint8_t *)read_buf(fp
, offset
, fat_BytesPerSector
);
127 pfat_entry
= (FAT_DES
*)sector
;
129 /* No more entries available. */
130 if (pfat_entry
->DIR_Name
[0] == 0) {
134 /* Skip empty or long name entries. */
135 if (pfat_entry
->DIR_Name
[0] == 0xe5 ||
136 (pfat_entry
->DIR_Attr
&
137 FAT_DES_ATTR_LONG_NAME
) ==
138 FAT_DES_ATTR_LONG_NAME
) {
143 * The name of the entry is the volume label if
144 * ATTR_VOLUME_ID is set.
146 if (pfat_entry
->DIR_Attr
&
147 FAT_DES_ATTR_VOLUME_ID
) {
148 strlcpy(label
, pfat_entry
->DIR_Name
,
150 sizeof(pfat_entry
->DIR_Name
) + 1));
153 } while((uint8_t *)(++pfat_entry
) <
154 (uint8_t *)(sector
+ fat_BytesPerSector
));