Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1#ifndef _LINUX_MSDOS_FS_H
2#define _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 CF_LE_W(v) le16_to_cpu(v)
19#define CF_LE_L(v) le32_to_cpu(v)
20#define CT_LE_W(v) cpu_to_le16(v)
21#define CT_LE_L(v) cpu_to_le32(v)
22
23
24#define MSDOS_ROOT_INO 1 /* == MINIX_ROOT_INO */
25#define MSDOS_DIR_BITS 5 /* log2(sizeof(struct msdos_dir_entry)) */
26
27/* directory limit */
28#define FAT_MAX_DIR_ENTRIES (65536)
29#define FAT_MAX_DIR_SIZE (FAT_MAX_DIR_ENTRIES << MSDOS_DIR_BITS)
30
31#define ATTR_NONE 0 /* no attribute bits */
32#define ATTR_RO 1 /* read-only */
33#define ATTR_HIDDEN 2 /* hidden */
34#define ATTR_SYS 4 /* system */
35#define ATTR_VOLUME 8 /* volume label */
36#define ATTR_DIR 16 /* directory */
37#define ATTR_ARCH 32 /* archived */
38
39/* attribute bits that are copied "as is" */
40#define ATTR_UNUSED (ATTR_VOLUME | ATTR_ARCH | ATTR_SYS | ATTR_HIDDEN)
41/* bits that are used by the Windows 95/Windows NT extended FAT */
42#define ATTR_EXT (ATTR_RO | ATTR_HIDDEN | ATTR_SYS | ATTR_VOLUME)
43
44#define CASE_LOWER_BASE 8 /* base is lower case */
45#define CASE_LOWER_EXT 16 /* extension is lower case */
46
47#define DELETED_FLAG 0xe5 /* marks file as deleted when in name[0] */
48#define IS_FREE(n) (!*(n) || *(n) == DELETED_FLAG)
49
50#define MSDOS_NAME 11 /* maximum name length */
51#define MSDOS_LONGNAME 256 /* maximum name length */
52#define MSDOS_SLOTS 21 /* max # of slots for short and long names */
53#define MSDOS_DOT ". " /* ".", padded to MSDOS_NAME chars */
54#define MSDOS_DOTDOT ".. " /* "..", padded to MSDOS_NAME chars */
55
56#define FAT_FIRST_ENT(s, x) ((MSDOS_SB(s)->fat_bits == 32 ? 0x0FFFFF00 : \
57 MSDOS_SB(s)->fat_bits == 16 ? 0xFF00 : 0xF00) | (x))
58
59/* start of data cluster's entry (number of reserved clusters) */
60#define FAT_START_ENT 2
61
62/* maximum number of clusters */
63#define MAX_FAT12 0xFF4
64#define MAX_FAT16 0xFFF4
65#define MAX_FAT32 0x0FFFFFF6
66#define MAX_FAT(s) (MSDOS_SB(s)->fat_bits == 32 ? MAX_FAT32 : \
67 MSDOS_SB(s)->fat_bits == 16 ? MAX_FAT16 : MAX_FAT12)
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
88struct __fat_dirent {
89 long d_ino;
90 __kernel_off_t d_off;
91 unsigned short d_reclen;
92 char d_name[256]; /* We must not include limits.h! */
93};
94
95/*
96 * ioctl commands
97 */
98#define VFAT_IOCTL_READDIR_BOTH _IOR('r', 1, struct __fat_dirent[2])
99#define VFAT_IOCTL_READDIR_SHORT _IOR('r', 2, struct __fat_dirent[2])
100/* <linux/videotext.h> has used 0x72 ('r') in collision, so skip a few */
101#define FAT_IOCTL_GET_ATTRIBUTES _IOR('r', 0x10, __u32)
102#define FAT_IOCTL_SET_ATTRIBUTES _IOW('r', 0x11, __u32)
103
104struct fat_boot_sector {
105 __u8 ignored[3]; /* Boot strap short or near jump */
106 __u8 system_id[8]; /* Name - can be used to special case
107 partition manager volumes */
108 __u8 sector_size[2]; /* bytes per logical sector */
109 __u8 sec_per_clus; /* sectors/cluster */
110 __le16 reserved; /* reserved sectors */
111 __u8 fats; /* number of FATs */
112 __u8 dir_entries[2]; /* root directory entries */
113 __u8 sectors[2]; /* number of sectors */
114 __u8 media; /* media code */
115 __le16 fat_length; /* sectors/FAT */
116 __le16 secs_track; /* sectors per track */
117 __le16 heads; /* number of heads */
118 __le32 hidden; /* hidden sectors (unused) */
119 __le32 total_sect; /* number of sectors (if sectors == 0) */
120
121 /* The following fields are only used by FAT32 */
122 __le32 fat32_length; /* sectors/FAT */
123 __le16 flags; /* bit 8: fat mirroring, low 4: active fat */
124 __u8 version[2]; /* major, minor filesystem version */
125 __le32 root_cluster; /* first cluster in root directory */
126 __le16 info_sector; /* filesystem info sector */
127 __le16 backup_boot; /* backup boot sector */
128 __le16 reserved2[6]; /* Unused */
129};
130
131struct fat_boot_fsinfo {
132 __le32 signature1; /* 0x41615252L */
133 __le32 reserved1[120]; /* Nothing as far as I can tell */
134 __le32 signature2; /* 0x61417272L */
135 __le32 free_clusters; /* Free cluster count. -1 if unknown */
136 __le32 next_cluster; /* Most recently allocated cluster */
137 __le32 reserved2[4];
138};
139
140struct msdos_dir_entry {
141 __u8 name[MSDOS_NAME];/* name and extension */
142 __u8 attr; /* attribute bits */
143 __u8 lcase; /* Case for base and extension */
144 __u8 ctime_cs; /* Creation time, centiseconds (0-199) */
145 __le16 ctime; /* Creation time */
146 __le16 cdate; /* Creation date */
147 __le16 adate; /* Last access date */
148 __le16 starthi; /* High 16 bits of cluster in FAT32 */
149 __le16 time,date,start;/* time, date and first cluster */
150 __le32 size; /* file size (in bytes) */
151};
152
153/* Up to 13 characters of the name */
154struct msdos_dir_slot {
155 __u8 id; /* sequence number for slot */
156 __u8 name0_4[10]; /* first 5 characters in name */
157 __u8 attr; /* attribute byte */
158 __u8 reserved; /* always 0 */
159 __u8 alias_checksum; /* checksum for 8.3 alias */
160 __u8 name5_10[12]; /* 6 more characters in name */
161 __le16 start; /* starting cluster number, 0 in long slots */
162 __u8 name11_12[4]; /* last 2 characters in name */
163};
164
165#ifdef __KERNEL__
166/* media of boot sector */
167static inline int fat_valid_media(u8 media)
168{
169 return 0xf8 <= media || media == 0xf0;
170}
171#endif /* !__KERNEL__ */
172#endif /* !_LINUX_MSDOS_FS_H */