1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LINUX_FS_TYPES_H |
3 | #define _LINUX_FS_TYPES_H |
4 | |
5 | /* |
6 | * This is a header for the common implementation of dirent |
7 | * to fs on-disk file type conversion. Although the fs on-disk |
8 | * bits are specific to every file system, in practice, many |
9 | * file systems use the exact same on-disk format to describe |
10 | * the lower 3 file type bits that represent the 7 POSIX file |
11 | * types. |
12 | * |
13 | * It is important to note that the definitions in this |
14 | * header MUST NOT change. This would break both the |
15 | * userspace ABI and the on-disk format of filesystems |
16 | * using this code. |
17 | * |
18 | * All those file systems can use this generic code for the |
19 | * conversions. |
20 | */ |
21 | |
22 | /* |
23 | * struct dirent file types |
24 | * exposed to user via getdents(2), readdir(3) |
25 | * |
26 | * These match bits 12..15 of stat.st_mode |
27 | * (ie "(i_mode >> 12) & 15"). |
28 | */ |
29 | #define S_DT_SHIFT 12 |
30 | #define S_DT(mode) (((mode) & S_IFMT) >> S_DT_SHIFT) |
31 | #define S_DT_MASK (S_IFMT >> S_DT_SHIFT) |
32 | |
33 | /* these are defined by POSIX and also present in glibc's dirent.h */ |
34 | #define DT_UNKNOWN 0 |
35 | #define DT_FIFO 1 |
36 | #define DT_CHR 2 |
37 | #define DT_DIR 4 |
38 | #define DT_BLK 6 |
39 | #define DT_REG 8 |
40 | #define DT_LNK 10 |
41 | #define DT_SOCK 12 |
42 | #define DT_WHT 14 |
43 | |
44 | #define DT_MAX (S_DT_MASK + 1) /* 16 */ |
45 | |
46 | /* |
47 | * fs on-disk file types. |
48 | * Only the low 3 bits are used for the POSIX file types. |
49 | * Other bits are reserved for fs private use. |
50 | * These definitions are shared and used by multiple filesystems, |
51 | * and MUST NOT change under any circumstances. |
52 | * |
53 | * Note that no fs currently stores the whiteout type on-disk, |
54 | * so whiteout dirents are exposed to user as DT_CHR. |
55 | */ |
56 | #define FT_UNKNOWN 0 |
57 | #define FT_REG_FILE 1 |
58 | #define FT_DIR 2 |
59 | #define FT_CHRDEV 3 |
60 | #define FT_BLKDEV 4 |
61 | #define FT_FIFO 5 |
62 | #define FT_SOCK 6 |
63 | #define FT_SYMLINK 7 |
64 | |
65 | #define FT_MAX 8 |
66 | |
67 | /* |
68 | * declarations for helper functions, accompanying implementation |
69 | * is in fs/fs_types.c |
70 | */ |
71 | extern unsigned char fs_ftype_to_dtype(unsigned int filetype); |
72 | extern unsigned char fs_umode_to_ftype(umode_t mode); |
73 | extern unsigned char fs_umode_to_dtype(umode_t mode); |
74 | |
75 | #endif |
76 | |