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git.ipfire.org Git - thirdparty/util-linux.git/blob - disk-utils/cramfs.h
2 * SPDX-License-Identifier: GPL-2.0-or-later
4 * cramfs_common - cramfs common code
6 * Copyright (c) 2008 Roy Peled, the.roy.peled -at- gmail
7 * Copyright (c) 2004-2006 by Juliane Holzt, kju -at- fqdn.org
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
24 #define CRAMFS_MAGIC 0x28cd3d45 /* some random number */
25 #define CRAMFS_SIGNATURE "Compressed ROMFS"
28 * Width of various bitfields in struct cramfs_inode.
29 * Primarily used to generate warnings in mkcramfs.
31 #define CRAMFS_MODE_WIDTH 16
32 #define CRAMFS_UID_WIDTH 16
33 #define CRAMFS_SIZE_WIDTH 24
34 #define CRAMFS_GID_WIDTH 8
35 #define CRAMFS_NAMELEN_WIDTH 6
36 #define CRAMFS_OFFSET_WIDTH 26
38 #ifndef HOST_IS_BIG_ENDIAN
39 #define HOST_IS_BIG_ENDIAN (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
43 * Reasonably terse representation of the inode data.
46 uint32_t mode
:16, uid
:16;
47 /* SIZE for device files is i_rdev */
48 uint32_t size
:24, gid
:8;
50 * NAMELEN is the length of the file name, divided by 4 and
51 * rounded up. (cramfs doesn't support hard links.)
53 * OFFSET: For symlinks and non-empty regular files, this
54 * contains the offset (divided by 4) of the file data in
55 * compressed form (starting with an array of block pointers;
56 * see README). For non-empty directories it is the offset
57 * (divided by 4) of the inode of the first file in that
58 * directory. For anything else, offset is zero.
60 uint32_t namelen
:6, offset
:26;
71 * Superblock information at the beginning of the FS.
74 uint32_t magic
; /* 0x28cd3d45 - random number */
75 uint32_t size
; /* Not used. mkcramfs currently
76 writes a constant 1<<16 here. */
77 uint32_t flags
; /* 0 */
78 uint32_t future
; /* 0 */
79 uint8_t signature
[16]; /* "Compressed ROMFS" */
80 struct cramfs_info fsid
;/* unique filesystem info */
81 uint8_t name
[16]; /* user-defined name */
82 struct cramfs_inode root
; /* Root inode data */
85 #define CRAMFS_FLAG_FSID_VERSION_2 0x00000001 /* fsid version #2 */
86 #define CRAMFS_FLAG_SORTED_DIRS 0x00000002 /* sorted dirs */
87 #define CRAMFS_FLAG_HOLES 0x00000100 /* support for holes */
88 #define CRAMFS_FLAG_WRONG_SIGNATURE 0x00000200 /* reserved */
89 #define CRAMFS_FLAG_SHIFTED_ROOT_OFFSET 0x00000400 /* shifted root fs */
92 * Valid values in super.flags. Currently we refuse to mount
93 * if (flags & ~CRAMFS_SUPPORTED_FLAGS). Maybe that should be
94 * changed to test super.future instead.
96 #define CRAMFS_SUPPORTED_FLAGS (0xff)
98 /* Uncompression interfaces to the underlying zlib */
99 int cramfs_uncompress_block(void *dst
, int dstlen
, void *src
, int srclen
);
100 int cramfs_uncompress_init(void);
101 int cramfs_uncompress_exit(void);
103 uint32_t u32_toggle_endianness(int big_endian
, uint32_t what
);
104 void super_toggle_endianness(int from_big_endian
, struct cramfs_super
*super
);
105 void inode_to_host(int from_big_endian
, struct cramfs_inode
*inode_in
,
106 struct cramfs_inode
*inode_out
);
107 void inode_from_host(int to_big_endian
, struct cramfs_inode
*inode_in
,
108 struct cramfs_inode
*inode_out
);