summaryrefslogtreecommitdiff
path: root/include/uapi/linux/msdos_fs.h
blob: a45d0754102e00829af76424a0a97fbcf4cd1f0f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef _UAPI_LINUX_MSDOS_FS_H
#define _UAPI_LINUX_MSDOS_FS_H

#include <linux/types.h>
#include <linux/magic.h>
#include <asm/byteorder.h>

/*
 * The MS-DOS filesystem constants/structures
 */

#define SECTOR_SIZE	512		/* sector size (bytes) */
#define SECTOR_BITS	9		/* log2(SECTOR_SIZE) */
#define MSDOS_DPB	(MSDOS_DPS)	/* dir entries per block */
#define MSDOS_DPB_BITS	4		/* log2(MSDOS_DPB) */
#define MSDOS_DPS	(SECTOR_SIZE / sizeof(struct msdos_dir_entry))
#define MSDOS_DPS_BITS	4		/* log2(MSDOS_DPS) */
#define MSDOS_LONGNAME	256		/* maximum name length */
#define CF_LE_W(v)	le16_to_cpu(v)
#define CF_LE_L(v)	le32_to_cpu(v)
#define CT_LE_W(v)	cpu_to_le16(v)
#define CT_LE_L(v)	cpu_to_le32(v)

#define MSDOS_ROOT_INO	 1	/* The root inode number */
#define MSDOS_FSINFO_INO 2	/* Used for managing the FSINFO block */

#define MSDOS_DIR_BITS	5	/* log2(sizeof(struct msdos_dir_entry)) */

/* directory limit */
#define FAT_MAX_DIR_ENTRIES	(65536)
#define FAT_MAX_DIR_SIZE	(FAT_MAX_DIR_ENTRIES << MSDOS_DIR_BITS)

#define ATTR_NONE	0	/* no attribute bits */
#define ATTR_RO		1	/* read-only */
#define ATTR_HIDDEN	2	/* hidden */
#define ATTR_SYS	4	/* system */
#define ATTR_VOLUME	8	/* volume label */
#define ATTR_DIR	16	/* directory */
#define ATTR_ARCH	32	/* archived */

/* attribute bits that are copied "as is" */
#define ATTR_UNUSED	(ATTR_VOLUME | ATTR_ARCH | ATTR_SYS | ATTR_HIDDEN)
/* bits that are used by the Windows 95/Windows NT extended FAT */
#define ATTR_EXT	(ATTR_RO | ATTR_HIDDEN | ATTR_SYS | ATTR_VOLUME)

#define CASE_LOWER_BASE	8	/* base is lower case */
#define CASE_LOWER_EXT	16	/* extension is lower case */

#define DELETED_FLAG	0xe5	/* marks file as deleted when in name[0] */
#define IS_FREE(n)	(!*(n) || *(n) == DELETED_FLAG)

#define FAT_LFN_LEN	255	/* maximum long name length */
#define MSDOS_NAME	11	/* maximum name length */
#define MSDOS_SLOTS	21	/* max # of slots for short and long names */
#define MSDOS_DOT	".          "	/* ".", padded to MSDOS_NAME chars */
#define MSDOS_DOTDOT	"..         "	/* "..", padded to MSDOS_NAME chars */

#define FAT_FIRST_ENT(s, x)	((MSDOS_SB(s)->fat_bits == 32 ? 0x0FFFFF00 : \
	MSDOS_SB(s)->fat_bits == 16 ? 0xFF00 : 0xF00) | (x))

/* start of data cluster's entry (number of reserved clusters) */
#define FAT_START_ENT	2

/* maximum number of clusters */
#define MAX_FAT12	0xFF4
#define MAX_FAT16	0xFFF4
#define MAX_FAT32	0x0FFFFFF6
#define MAX_FAT(s)	(MSDOS_SB(s)->fat_bits == 32 ? MAX_FAT32 : \
	MSDOS_SB(s)->fat_bits == 16 ? MAX_FAT16 : MAX_FAT12)

/* bad cluster mark */
#define BAD_FAT12	0xFF7
#define BAD_FAT16	0xFFF7
#define BAD_FAT32	0x0FFFFFF7

/* standard EOF */
#define EOF_FAT12	0xFFF
#define EOF_FAT16	0xFFFF
#define EOF_FAT32	0x0FFFFFFF

#define FAT_ENT_FREE	(0)
#define FAT_ENT_BAD	(BAD_FAT32)
#define FAT_ENT_EOF	(EOF_FAT32)

#define FAT_FSINFO_SIG1	0x41615252
#define FAT_FSINFO_SIG2	0x61417272
#define IS_FSINFO(x)	(le32_to_cpu((x)->signature1) == FAT_FSINFO_SIG1 \
			 && le32_to_cpu((x)->signature2) == FAT_FSINFO_SIG2)

#define FAT_STATE_DIRTY 0x01

struct __fat_dirent {
	long		d_ino;
	__kernel_off_t	d_off;
	unsigned short	d_reclen;
	char		d_name[256]; /* We must not include limits.h! */
};

/*
 * ioctl commands
 */
#define VFAT_IOCTL_READDIR_BOTH		_IOR('r', 1, struct __fat_dirent[2])
#define VFAT_IOCTL_READDIR_SHORT	_IOR('r', 2, struct __fat_dirent[2])
/* <linux/videotext.h> has used 0x72 ('r') in collision, so skip a few */
#define FAT_IOCTL_GET_ATTRIBUTES	_IOR('r', 0x10, __u32)
#define FAT_IOCTL_SET_ATTRIBUTES	_IOW('r', 0x11, __u32)
/*Android kernel has used 0x12, so we use 0x13*/
#define FAT_IOCTL_GET_VOLUME_ID		_IOR('r', 0x13, __u32)

struct fat_boot_sector {
	__u8	ignored[3];	/* Boot strap short or near jump */
	__u8	system_id[8];	/* Name - can be used to special case
				   partition manager volumes */
	__u8	sector_size[2];	/* bytes per logical sector */
	__u8	sec_per_clus;	/* sectors/cluster */
	__le16	reserved;	/* reserved sectors */
	__u8	fats;		/* number of FATs */
	__u8	dir_entries[2];	/* root directory entries */
	__u8	sectors[2];	/* number of sectors */
	__u8	media;		/* media code */
	__le16	fat_length;	/* sectors/FAT */
	__le16	secs_track;	/* sectors per track */
	__le16	heads;		/* number of heads */
	__le32	hidden;		/* hidden sectors (unused) */
	__le32	total_sect;	/* number of sectors (if sectors == 0) */

	union {
		struct {
			/*  Extended BPB Fields for FAT16 */
			__u8	drive_number;	/* Physical drive number */
			__u8	state;		/* undocumented, but used
						   for mount state. */
			__u8	signature;  /* extended boot signature */
			__u8	vol_id[4];	/* volume ID */
			__u8	vol_label[11];	/* volume label */
			__u8	fs_type[8];		/* file system type */
			/* other fields are not added here */
		} fat16;

		struct {
			/* only used by FAT32 */
			__le32	length;		/* sectors/FAT */
			__le16	flags;		/* bit 8: fat mirroring,
						   low 4: active fat */
			__u8	version[2];	/* major, minor filesystem
						   version */
			__le32	root_cluster;	/* first cluster in
						   root directory */
			__le16	info_sector;	/* filesystem info sector */
			__le16	backup_boot;	/* backup boot sector */
			__le16	reserved2[6];	/* Unused */
			/* Extended BPB Fields for FAT32 */
			__u8	drive_number;   /* Physical drive number */
			__u8    state;       	/* undocumented, but used
						   for mount state. */
			__u8	signature;  /* extended boot signature */
			__u8	vol_id[4];	/* volume ID */
			__u8	vol_label[11];	/* volume label */
			__u8	fs_type[8];		/* file system type */
			/* other fields are not added here */
		} fat32;
	};
};

struct fat_boot_fsinfo {
	__le32   signature1;	/* 0x41615252L */
	__le32   reserved1[120];	/* Nothing as far as I can tell */
	__le32   signature2;	/* 0x61417272L */
	__le32   free_clusters;	/* Free cluster count.  -1 if unknown */
	__le32   next_cluster;	/* Most recently allocated cluster */
	__le32   reserved2[4];
};

struct msdos_dir_entry {
	__u8	name[MSDOS_NAME];/* name and extension */
	__u8	attr;		/* attribute bits */
	__u8    lcase;		/* Case for base and extension */
	__u8	ctime_cs;	/* Creation time, centiseconds (0-199) */
	__le16	ctime;		/* Creation time */
	__le16	cdate;		/* Creation date */
	__le16	adate;		/* Last access date */
	__le16	starthi;	/* High 16 bits of cluster in FAT32 */
	__le16	time,date,start;/* time, date and first cluster */
	__le32	size;		/* file size (in bytes) */
};

/* Up to 13 characters of the name */
struct msdos_dir_slot {
	__u8    id;		/* sequence number for slot */
	__u8    name0_4[10];	/* first 5 characters in name */
	__u8    attr;		/* attribute byte */
	__u8    reserved;	/* always 0 */
	__u8    alias_checksum;	/* checksum for 8.3 alias */
	__u8    name5_10[12];	/* 6 more characters in name */
	__le16   start;		/* starting cluster number, 0 in long slots */
	__u8    name11_12[4];	/* last 2 characters in name */
};

#endif /* _UAPI_LINUX_MSDOS_FS_H */