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git.ipfire.org Git - thirdparty/util-linux.git/blob - disk-utils/cramfs.h
2 * cramfs_common - cramfs common code
4 * Copyright (c) 2008 Roy Peled, the.roy.peled -at- gmail
5 * Copyright (c) 2004-2006 by Juliane Holzt, kju -at- fqdn.org
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * 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 #ifdef WORDS_BIGENDIAN
40 #define HOST_IS_BIG_ENDIAN 1
42 #define HOST_IS_BIG_ENDIAN 0
47 * Reasonably terse representation of the inode data.
50 uint32_t mode
:16, uid
:16;
51 /* SIZE for device files is i_rdev */
52 uint32_t size
:24, gid
:8;
54 * NAMELEN is the length of the file name, divided by 4 and
55 * rounded up. (cramfs doesn't support hard links.)
57 * OFFSET: For symlinks and non-empty regular files, this
58 * contains the offset (divided by 4) of the file data in
59 * compressed form (starting with an array of block pointers;
60 * see README). For non-empty directories it is the offset
61 * (divided by 4) of the inode of the first file in that
62 * directory. For anything else, offset is zero.
64 uint32_t namelen
:6, offset
:26;
75 * Superblock information at the beginning of the FS.
78 uint32_t magic
; /* 0x28cd3d45 - random number */
79 uint32_t size
; /* Not used. mkcramfs currently
80 writes a constant 1<<16 here. */
81 uint32_t flags
; /* 0 */
82 uint32_t future
; /* 0 */
83 uint8_t signature
[16]; /* "Compressed ROMFS" */
84 struct cramfs_info fsid
;/* unique filesystem info */
85 uint8_t name
[16]; /* user-defined name */
86 struct cramfs_inode root
; /* Root inode data */
89 #define CRAMFS_FLAG_FSID_VERSION_2 0x00000001 /* fsid version #2 */
90 #define CRAMFS_FLAG_SORTED_DIRS 0x00000002 /* sorted dirs */
91 #define CRAMFS_FLAG_HOLES 0x00000100 /* support for holes */
92 #define CRAMFS_FLAG_WRONG_SIGNATURE 0x00000200 /* reserved */
93 #define CRAMFS_FLAG_SHIFTED_ROOT_OFFSET 0x00000400 /* shifted root fs */
96 * Valid values in super.flags. Currently we refuse to mount
97 * if (flags & ~CRAMFS_SUPPORTED_FLAGS). Maybe that should be
98 * changed to test super.future instead.
100 #define CRAMFS_SUPPORTED_FLAGS (0xff)
102 /* Uncompression interfaces to the underlying zlib */
103 int cramfs_uncompress_block(void *dst
, int dstlen
, void *src
, int srclen
);
104 int cramfs_uncompress_init(void);
105 int cramfs_uncompress_exit(void);
107 uint32_t u32_toggle_endianness(int big_endian
, uint32_t what
);
108 void super_toggle_endianness(int from_big_endian
, struct cramfs_super
*super
);
109 void inode_to_host(int from_big_endian
, struct cramfs_inode
*inode_in
,
110 struct cramfs_inode
*inode_out
);
111 void inode_from_host(int to_big_endian
, struct cramfs_inode
*inode_in
,
112 struct cramfs_inode
*inode_out
);