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msdos_fs.h
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1 #ifndef _UAPI_LINUX_MSDOS_FS_H
2 #define _UAPI_LINUX_MSDOS_FS_H
3 
4 #include <linux/types.h>
5 #include <linux/magic.h>
6 #include <asm/byteorder.h>
7 
8 /*
9  * The MS-DOS filesystem constants/structures
10  */
11 
12 #define SECTOR_SIZE 512 /* sector size (bytes) */
13 #define SECTOR_BITS 9 /* log2(SECTOR_SIZE) */
14 #define MSDOS_DPB (MSDOS_DPS) /* dir entries per block */
15 #define MSDOS_DPB_BITS 4 /* log2(MSDOS_DPB) */
16 #define MSDOS_DPS (SECTOR_SIZE / sizeof(struct msdos_dir_entry))
17 #define MSDOS_DPS_BITS 4 /* log2(MSDOS_DPS) */
18 #define MSDOS_LONGNAME 256 /* maximum name length */
19 #define CF_LE_W(v) le16_to_cpu(v)
20 #define CF_LE_L(v) le32_to_cpu(v)
21 #define CT_LE_W(v) cpu_to_le16(v)
22 #define CT_LE_L(v) cpu_to_le32(v)
23 
24 #define MSDOS_ROOT_INO 1 /* The root inode number */
25 #define MSDOS_FSINFO_INO 2 /* Used for managing the FSINFO block */
26 
27 #define MSDOS_DIR_BITS 5 /* log2(sizeof(struct msdos_dir_entry)) */
28 
29 /* directory limit */
30 #define FAT_MAX_DIR_ENTRIES (65536)
31 #define FAT_MAX_DIR_SIZE (FAT_MAX_DIR_ENTRIES << MSDOS_DIR_BITS)
32 
33 #define ATTR_NONE 0 /* no attribute bits */
34 #define ATTR_RO 1 /* read-only */
35 #define ATTR_HIDDEN 2 /* hidden */
36 #define ATTR_SYS 4 /* system */
37 #define ATTR_VOLUME 8 /* volume label */
38 #define ATTR_DIR 16 /* directory */
39 #define ATTR_ARCH 32 /* archived */
40 
41 /* attribute bits that are copied "as is" */
42 #define ATTR_UNUSED (ATTR_VOLUME | ATTR_ARCH | ATTR_SYS | ATTR_HIDDEN)
43 /* bits that are used by the Windows 95/Windows NT extended FAT */
44 #define ATTR_EXT (ATTR_RO | ATTR_HIDDEN | ATTR_SYS | ATTR_VOLUME)
45 
46 #define CASE_LOWER_BASE 8 /* base is lower case */
47 #define CASE_LOWER_EXT 16 /* extension is lower case */
48 
49 #define DELETED_FLAG 0xe5 /* marks file as deleted when in name[0] */
50 #define IS_FREE(n) (!*(n) || *(n) == DELETED_FLAG)
51 
52 #define FAT_LFN_LEN 255 /* maximum long name length */
53 #define MSDOS_NAME 11 /* maximum name length */
54 #define MSDOS_SLOTS 21 /* max # of slots for short and long names */
55 #define MSDOS_DOT ". " /* ".", padded to MSDOS_NAME chars */
56 #define MSDOS_DOTDOT ".. " /* "..", padded to MSDOS_NAME chars */
57 
58 #define FAT_FIRST_ENT(s, x) ((MSDOS_SB(s)->fat_bits == 32 ? 0x0FFFFF00 : \
59  MSDOS_SB(s)->fat_bits == 16 ? 0xFF00 : 0xF00) | (x))
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 #define MAX_FAT(s) (MSDOS_SB(s)->fat_bits == 32 ? MAX_FAT32 : \
69  MSDOS_SB(s)->fat_bits == 16 ? MAX_FAT16 : MAX_FAT12)
70 
71 /* bad cluster mark */
72 #define BAD_FAT12 0xFF7
73 #define BAD_FAT16 0xFFF7
74 #define BAD_FAT32 0x0FFFFFF7
75 
76 /* standard EOF */
77 #define EOF_FAT12 0xFFF
78 #define EOF_FAT16 0xFFFF
79 #define EOF_FAT32 0x0FFFFFFF
80 
81 #define FAT_ENT_FREE (0)
82 #define FAT_ENT_BAD (BAD_FAT32)
83 #define FAT_ENT_EOF (EOF_FAT32)
84 
85 #define FAT_FSINFO_SIG1 0x41615252
86 #define FAT_FSINFO_SIG2 0x61417272
87 #define IS_FSINFO(x) (le32_to_cpu((x)->signature1) == FAT_FSINFO_SIG1 \
88  && le32_to_cpu((x)->signature2) == FAT_FSINFO_SIG2)
89 
90 struct __fat_dirent {
91  long d_ino;
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 
107  __u8 ignored[3]; /* Boot strap short or near jump */
108  __u8 system_id[8]; /* Name - can be used to special case
109  partition manager volumes */
110  __u8 sector_size[2]; /* bytes per logical sector */
111  __u8 sec_per_clus; /* sectors/cluster */
112  __le16 reserved; /* reserved sectors */
113  __u8 fats; /* number of FATs */
114  __u8 dir_entries[2]; /* root directory entries */
115  __u8 sectors[2]; /* number of sectors */
116  __u8 media; /* media code */
117  __le16 fat_length; /* sectors/FAT */
118  __le16 secs_track; /* sectors per track */
119  __le16 heads; /* number of heads */
120  __le32 hidden; /* hidden sectors (unused) */
121  __le32 total_sect; /* number of sectors (if sectors == 0) */
122 
123  /* The following fields are only used by FAT32 */
124  __le32 fat32_length; /* sectors/FAT */
125  __le16 flags; /* bit 8: fat mirroring, low 4: active fat */
126  __u8 version[2]; /* major, minor filesystem version */
127  __le32 root_cluster; /* first cluster in root directory */
128  __le16 info_sector; /* filesystem info sector */
129  __le16 backup_boot; /* backup boot sector */
130  __le16 reserved2[6]; /* Unused */
131 };
132 
134  __le32 signature1; /* 0x41615252L */
135  __le32 reserved1[120]; /* Nothing as far as I can tell */
136  __le32 signature2; /* 0x61417272L */
137  __le32 free_clusters; /* Free cluster count. -1 if unknown */
138  __le32 next_cluster; /* Most recently allocated cluster */
140 };
141 
143  __u8 name[MSDOS_NAME];/* name and extension */
144  __u8 attr; /* attribute bits */
145  __u8 lcase; /* Case for base and extension */
146  __u8 ctime_cs; /* Creation time, centiseconds (0-199) */
147  __le16 ctime; /* Creation time */
148  __le16 cdate; /* Creation date */
149  __le16 adate; /* Last access date */
150  __le16 starthi; /* High 16 bits of cluster in FAT32 */
151  __le16 time,date,start;/* time, date and first cluster */
152  __le32 size; /* file size (in bytes) */
153 };
154 
155 /* Up to 13 characters of the name */
157  __u8 id; /* sequence number for slot */
158  __u8 name0_4[10]; /* first 5 characters in name */
159  __u8 attr; /* attribute byte */
160  __u8 reserved; /* always 0 */
161  __u8 alias_checksum; /* checksum for 8.3 alias */
162  __u8 name5_10[12]; /* 6 more characters in name */
163  __le16 start; /* starting cluster number, 0 in long slots */
164  __u8 name11_12[4]; /* last 2 characters in name */
165 };
166 
167 #endif /* _UAPI_LINUX_MSDOS_FS_H */