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1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2#ifndef _LINUX_MSDOS_FS_H
3#define _LINUX_MSDOS_FS_H
4
5#include <linux/types.h>
6#include <linux/magic.h>
7#include <asm/byteorder.h>
8
9/*
10 * The MS-DOS filesystem constants/structures
11 */
12
13#ifndef SECTOR_SIZE
14#define SECTOR_SIZE 512 /* sector size (bytes) */
15#endif
16#define SECTOR_BITS 9 /* log2(SECTOR_SIZE) */
17#define MSDOS_DPB (MSDOS_DPS) /* dir entries per block */
18#define MSDOS_DPB_BITS 4 /* log2(MSDOS_DPB) */
19#define MSDOS_DPS (SECTOR_SIZE / sizeof(struct msdos_dir_entry))
20#define MSDOS_DPS_BITS 4 /* log2(MSDOS_DPS) */
21#define MSDOS_LONGNAME 256 /* maximum name length */
22#define CF_LE_W(v) le16_to_cpu(v)
23#define CF_LE_L(v) le32_to_cpu(v)
24#define CT_LE_W(v) cpu_to_le16(v)
25#define CT_LE_L(v) cpu_to_le32(v)
26
27#define MSDOS_ROOT_INO 1 /* The root inode number */
28#define MSDOS_FSINFO_INO 2 /* Used for managing the FSINFO block */
29
30#define MSDOS_DIR_BITS 5 /* log2(sizeof(struct msdos_dir_entry)) */
31
32/* directory limit */
33#define FAT_MAX_DIR_ENTRIES (65536)
34#define FAT_MAX_DIR_SIZE (FAT_MAX_DIR_ENTRIES << MSDOS_DIR_BITS)
35
36#define ATTR_NONE 0 /* no attribute bits */
37#define ATTR_RO 1 /* read-only */
38#define ATTR_HIDDEN 2 /* hidden */
39#define ATTR_SYS 4 /* system */
40#define ATTR_VOLUME 8 /* volume label */
41#define ATTR_DIR 16 /* directory */
42#define ATTR_ARCH 32 /* archived */
43
44/* attribute bits that are copied "as is" */
45#define ATTR_UNUSED (ATTR_VOLUME | ATTR_ARCH | ATTR_SYS | ATTR_HIDDEN)
46/* bits that are used by the Windows 95/Windows NT extended FAT */
47#define ATTR_EXT (ATTR_RO | ATTR_HIDDEN | ATTR_SYS | ATTR_VOLUME)
48
49#define CASE_LOWER_BASE 8 /* base is lower case */
50#define CASE_LOWER_EXT 16 /* extension is lower case */
51
52#define DELETED_FLAG 0xe5 /* marks file as deleted when in name[0] */
53#define IS_FREE(n) (!*(n) || *(n) == DELETED_FLAG)
54
55#define FAT_LFN_LEN 255 /* maximum long name length */
56#define MSDOS_NAME 11 /* maximum name length */
57#define MSDOS_SLOTS 21 /* max # of slots for short and long names */
58#define MSDOS_DOT ". " /* ".", padded to MSDOS_NAME chars */
59#define MSDOS_DOTDOT ".. " /* "..", padded to MSDOS_NAME chars */
60
61/* start of data cluster's entry (number of reserved clusters) */
62#define FAT_START_ENT 2
63
64/* maximum number of clusters */
65#define MAX_FAT12 0xFF4
66#define MAX_FAT16 0xFFF4
67#define MAX_FAT32 0x0FFFFFF6
68
69/* bad cluster mark */
70#define BAD_FAT12 0xFF7
71#define BAD_FAT16 0xFFF7
72#define BAD_FAT32 0x0FFFFFF7
73
74/* standard EOF */
75#define EOF_FAT12 0xFFF
76#define EOF_FAT16 0xFFFF
77#define EOF_FAT32 0x0FFFFFFF
78
79#define FAT_ENT_FREE (0)
80#define FAT_ENT_BAD (BAD_FAT32)
81#define FAT_ENT_EOF (EOF_FAT32)
82
83#define FAT_FSINFO_SIG1 0x41615252
84#define FAT_FSINFO_SIG2 0x61417272
85#define IS_FSINFO(x) (le32_to_cpu((x)->signature1) == FAT_FSINFO_SIG1 \
86 && le32_to_cpu((x)->signature2) == FAT_FSINFO_SIG2)
87
88#define FAT_STATE_DIRTY 0x01
89
90struct __fat_dirent {
91 long d_ino;
92 __kernel_off_t d_off;
93 unsigned short d_reclen;
94 char d_name[256]; /* We must not include limits.h! */
95};
96
97/*
98 * ioctl commands
99 */
100#define VFAT_IOCTL_READDIR_BOTH _IOR('r', 1, struct __fat_dirent[2])
101#define VFAT_IOCTL_READDIR_SHORT _IOR('r', 2, struct __fat_dirent[2])
102/* <linux/videotext.h> has used 0x72 ('r') in collision, so skip a few */
103#define FAT_IOCTL_GET_ATTRIBUTES _IOR('r', 0x10, __u32)
104#define FAT_IOCTL_SET_ATTRIBUTES _IOW('r', 0x11, __u32)
105/*Android kernel has used 0x12, so we use 0x13*/
106#define FAT_IOCTL_GET_VOLUME_ID _IOR('r', 0x13, __u32)
107
108struct fat_boot_sector {
109 __u8 ignored[3]; /* Boot strap short or near jump */
110 __u8 system_id[8]; /* Name - can be used to special case
111 partition manager volumes */
112 __u8 sector_size[2]; /* bytes per logical sector */
113 __u8 sec_per_clus; /* sectors/cluster */
114 __le16 reserved; /* reserved sectors */
115 __u8 fats; /* number of FATs */
116 __u8 dir_entries[2]; /* root directory entries */
117 __u8 sectors[2]; /* number of sectors */
118 __u8 media; /* media code */
119 __le16 fat_length; /* sectors/FAT */
120 __le16 secs_track; /* sectors per track */
121 __le16 heads; /* number of heads */
122 __le32 hidden; /* hidden sectors (unused) */
123 __le32 total_sect; /* number of sectors (if sectors == 0) */
124
125 union {
126 struct {
127 /* Extended BPB Fields for FAT16 */
128 __u8 drive_number; /* Physical drive number */
129 __u8 state; /* undocumented, but used
130 for mount state. */
131 __u8 signature; /* extended boot signature */
132 __u8 vol_id[4]; /* volume ID */
133 __u8 vol_label[MSDOS_NAME]; /* volume label */
134 __u8 fs_type[8]; /* file system type */
135 /* other fields are not added here */
136 } fat16;
137
138 struct {
139 /* only used by FAT32 */
140 __le32 length; /* sectors/FAT */
141 __le16 flags; /* bit 8: fat mirroring,
142 low 4: active fat */
143 __u8 version[2]; /* major, minor filesystem
144 version */
145 __le32 root_cluster; /* first cluster in
146 root directory */
147 __le16 info_sector; /* filesystem info sector */
148 __le16 backup_boot; /* backup boot sector */
149 __le16 reserved2[6]; /* Unused */
150 /* Extended BPB Fields for FAT32 */
151 __u8 drive_number; /* Physical drive number */
152 __u8 state; /* undocumented, but used
153 for mount state. */
154 __u8 signature; /* extended boot signature */
155 __u8 vol_id[4]; /* volume ID */
156 __u8 vol_label[MSDOS_NAME]; /* volume label */
157 __u8 fs_type[8]; /* file system type */
158 /* other fields are not added here */
159 } fat32;
160 };
161};
162
163struct fat_boot_fsinfo {
164 __le32 signature1; /* 0x41615252L */
165 __le32 reserved1[120]; /* Nothing as far as I can tell */
166 __le32 signature2; /* 0x61417272L */
167 __le32 free_clusters; /* Free cluster count. -1 if unknown */
168 __le32 next_cluster; /* Most recently allocated cluster */
169 __le32 reserved2[4];
170};
171
172struct msdos_dir_entry {
173 __u8 name[MSDOS_NAME];/* name and extension */
174 __u8 attr; /* attribute bits */
175 __u8 lcase; /* Case for base and extension */
176 __u8 ctime_cs; /* Creation time, centiseconds (0-199) */
177 __le16 ctime; /* Creation time */
178 __le16 cdate; /* Creation date */
179 __le16 adate; /* Last access date */
180 __le16 starthi; /* High 16 bits of cluster in FAT32 */
181 __le16 time,date,start;/* time, date and first cluster */
182 __le32 size; /* file size (in bytes) */
183};
184
185/* Up to 13 characters of the name */
186struct msdos_dir_slot {
187 __u8 id; /* sequence number for slot */
188 __u8 name0_4[10]; /* first 5 characters in name */
189 __u8 attr; /* attribute byte */
190 __u8 reserved; /* always 0 */
191 __u8 alias_checksum; /* checksum for 8.3 alias */
192 __u8 name5_10[12]; /* 6 more characters in name */
193 __le16 start; /* starting cluster number, 0 in long slots */
194 __u8 name11_12[4]; /* last 2 characters in name */
195};
196
197#endif /* _LINUX_MSDOS_FS_H */