1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef _UAPI_LINUX_MSDOS_FS_H
3 #define _UAPI_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 #define FAT_FIRST_ENT(s, x)	((MSDOS_SB(s)->fat_bits == 32 ? 0x0FFFFF00 : \
62 	MSDOS_SB(s)->fat_bits == 16 ? 0xFF00 : 0xF00) | (x))
63 
64 /* start of data cluster's entry (number of reserved clusters) */
65 #define FAT_START_ENT	2
66 
67 /* maximum number of clusters */
68 #define MAX_FAT12	0xFF4
69 #define MAX_FAT16	0xFFF4
70 #define MAX_FAT32	0x0FFFFFF6
71 #define MAX_FAT(s)	(MSDOS_SB(s)->fat_bits == 32 ? MAX_FAT32 : \
72 	MSDOS_SB(s)->fat_bits == 16 ? MAX_FAT16 : MAX_FAT12)
73 
74 /* bad cluster mark */
75 #define BAD_FAT12	0xFF7
76 #define BAD_FAT16	0xFFF7
77 #define BAD_FAT32	0x0FFFFFF7
78 
79 /* standard EOF */
80 #define EOF_FAT12	0xFFF
81 #define EOF_FAT16	0xFFFF
82 #define EOF_FAT32	0x0FFFFFFF
83 
84 #define FAT_ENT_FREE	(0)
85 #define FAT_ENT_BAD	(BAD_FAT32)
86 #define FAT_ENT_EOF	(EOF_FAT32)
87 
88 #define FAT_FSINFO_SIG1	0x41615252
89 #define FAT_FSINFO_SIG2	0x61417272
90 #define IS_FSINFO(x)	(le32_to_cpu((x)->signature1) == FAT_FSINFO_SIG1 \
91 			 && le32_to_cpu((x)->signature2) == FAT_FSINFO_SIG2)
92 
93 #define FAT_STATE_DIRTY 0x01
94 
95 struct __fat_dirent {
96 	long		d_ino;
97 	__kernel_off_t	d_off;
98 	unsigned short	d_reclen;
99 	char		d_name[256]; /* We must not include limits.h! */
100 };
101 
102 /*
103  * ioctl commands
104  */
105 #define VFAT_IOCTL_READDIR_BOTH		_IOR('r', 1, struct __fat_dirent[2])
106 #define VFAT_IOCTL_READDIR_SHORT	_IOR('r', 2, struct __fat_dirent[2])
107 /* <linux/videotext.h> has used 0x72 ('r') in collision, so skip a few */
108 #define FAT_IOCTL_GET_ATTRIBUTES	_IOR('r', 0x10, __u32)
109 #define FAT_IOCTL_SET_ATTRIBUTES	_IOW('r', 0x11, __u32)
110 /*Android kernel has used 0x12, so we use 0x13*/
111 #define FAT_IOCTL_GET_VOLUME_ID		_IOR('r', 0x13, __u32)
112 
113 struct fat_boot_sector {
114 	__u8	ignored[3];	/* Boot strap short or near jump */
115 	__u8	system_id[8];	/* Name - can be used to special case
116 				   partition manager volumes */
117 	__u8	sector_size[2];	/* bytes per logical sector */
118 	__u8	sec_per_clus;	/* sectors/cluster */
119 	__le16	reserved;	/* reserved sectors */
120 	__u8	fats;		/* number of FATs */
121 	__u8	dir_entries[2];	/* root directory entries */
122 	__u8	sectors[2];	/* number of sectors */
123 	__u8	media;		/* media code */
124 	__le16	fat_length;	/* sectors/FAT */
125 	__le16	secs_track;	/* sectors per track */
126 	__le16	heads;		/* number of heads */
127 	__le32	hidden;		/* hidden sectors (unused) */
128 	__le32	total_sect;	/* number of sectors (if sectors == 0) */
129 
130 	union {
131 		struct {
132 			/*  Extended BPB Fields for FAT16 */
133 			__u8	drive_number;	/* Physical drive number */
134 			__u8	state;		/* undocumented, but used
135 						   for mount state. */
136 			__u8	signature;  /* extended boot signature */
137 			__u8	vol_id[4];	/* volume ID */
138 			__u8	vol_label[11];	/* volume label */
139 			__u8	fs_type[8];		/* file system type */
140 			/* other fields are not added here */
141 		} fat16;
142 
143 		struct {
144 			/* only used by FAT32 */
145 			__le32	length;		/* sectors/FAT */
146 			__le16	flags;		/* bit 8: fat mirroring,
147 						   low 4: active fat */
148 			__u8	version[2];	/* major, minor filesystem
149 						   version */
150 			__le32	root_cluster;	/* first cluster in
151 						   root directory */
152 			__le16	info_sector;	/* filesystem info sector */
153 			__le16	backup_boot;	/* backup boot sector */
154 			__le16	reserved2[6];	/* Unused */
155 			/* Extended BPB Fields for FAT32 */
156 			__u8	drive_number;   /* Physical drive number */
157 			__u8    state;       	/* undocumented, but used
158 						   for mount state. */
159 			__u8	signature;  /* extended boot signature */
160 			__u8	vol_id[4];	/* volume ID */
161 			__u8	vol_label[11];	/* volume label */
162 			__u8	fs_type[8];		/* file system type */
163 			/* other fields are not added here */
164 		} fat32;
165 	};
166 };
167 
168 struct fat_boot_fsinfo {
169 	__le32   signature1;	/* 0x41615252L */
170 	__le32   reserved1[120];	/* Nothing as far as I can tell */
171 	__le32   signature2;	/* 0x61417272L */
172 	__le32   free_clusters;	/* Free cluster count.  -1 if unknown */
173 	__le32   next_cluster;	/* Most recently allocated cluster */
174 	__le32   reserved2[4];
175 };
176 
177 struct msdos_dir_entry {
178 	__u8	name[MSDOS_NAME];/* name and extension */
179 	__u8	attr;		/* attribute bits */
180 	__u8    lcase;		/* Case for base and extension */
181 	__u8	ctime_cs;	/* Creation time, centiseconds (0-199) */
182 	__le16	ctime;		/* Creation time */
183 	__le16	cdate;		/* Creation date */
184 	__le16	adate;		/* Last access date */
185 	__le16	starthi;	/* High 16 bits of cluster in FAT32 */
186 	__le16	time,date,start;/* time, date and first cluster */
187 	__le32	size;		/* file size (in bytes) */
188 };
189 
190 /* Up to 13 characters of the name */
191 struct msdos_dir_slot {
192 	__u8    id;		/* sequence number for slot */
193 	__u8    name0_4[10];	/* first 5 characters in name */
194 	__u8    attr;		/* attribute byte */
195 	__u8    reserved;	/* always 0 */
196 	__u8    alias_checksum;	/* checksum for 8.3 alias */
197 	__u8    name5_10[12];	/* 6 more characters in name */
198 	__le16   start;		/* starting cluster number, 0 in long slots */
199 	__u8    name11_12[4];	/* last 2 characters in name */
200 };
201 
202 #endif /* _UAPI_LINUX_MSDOS_FS_H */
203