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Diffstat (limited to 'disk-utils/cramfs.h')
| -rw-r--r-- | disk-utils/cramfs.h | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/disk-utils/cramfs.h b/disk-utils/cramfs.h new file mode 100644 index 0000000..322dbf3 --- /dev/null +++ b/disk-utils/cramfs.h @@ -0,0 +1,110 @@ +/* + * SPDX-License-Identifier: GPL-2.0-or-later + * + * cramfs_common - cramfs common code + * + * Copyright (c) 2008 Roy Peled, the.roy.peled -at- gmail + * Copyright (c) 2004-2006 by Juliane Holzt, kju -at- fqdn.org + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ +#ifndef __CRAMFS_H +#define __CRAMFS_H + +#include <stdint.h> + +#define CRAMFS_MAGIC 0x28cd3d45 /* some random number */ +#define CRAMFS_SIGNATURE "Compressed ROMFS" + +/* + * Width of various bitfields in struct cramfs_inode. + * Primarily used to generate warnings in mkcramfs. + */ +#define CRAMFS_MODE_WIDTH 16 +#define CRAMFS_UID_WIDTH 16 +#define CRAMFS_SIZE_WIDTH 24 +#define CRAMFS_GID_WIDTH 8 +#define CRAMFS_NAMELEN_WIDTH 6 +#define CRAMFS_OFFSET_WIDTH 26 + +#ifndef HOST_IS_BIG_ENDIAN +#define HOST_IS_BIG_ENDIAN (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) +#endif + +/* + * Reasonably terse representation of the inode data. + */ +struct cramfs_inode { + uint32_t mode:16, uid:16; + /* SIZE for device files is i_rdev */ + uint32_t size:24, gid:8; + /* + * NAMELEN is the length of the file name, divided by 4 and + * rounded up. (cramfs doesn't support hard links.) + * + * OFFSET: For symlinks and non-empty regular files, this + * contains the offset (divided by 4) of the file data in + * compressed form (starting with an array of block pointers; + * see README). For non-empty directories it is the offset + * (divided by 4) of the inode of the first file in that + * directory. For anything else, offset is zero. + */ + uint32_t namelen:6, offset:26; +}; + +struct cramfs_info { + uint32_t crc; + uint32_t edition; + uint32_t blocks; + uint32_t files; +}; + +/* + * Superblock information at the beginning of the FS. + */ +struct cramfs_super { + uint32_t magic; /* 0x28cd3d45 - random number */ + uint32_t size; /* Not used. mkcramfs currently + writes a constant 1<<16 here. */ + uint32_t flags; /* 0 */ + uint32_t future; /* 0 */ + uint8_t signature[16]; /* "Compressed ROMFS" */ + struct cramfs_info fsid;/* unique filesystem info */ + uint8_t name[16]; /* user-defined name */ + struct cramfs_inode root; /* Root inode data */ +}; + +#define CRAMFS_FLAG_FSID_VERSION_2 0x00000001 /* fsid version #2 */ +#define CRAMFS_FLAG_SORTED_DIRS 0x00000002 /* sorted dirs */ +#define CRAMFS_FLAG_HOLES 0x00000100 /* support for holes */ +#define CRAMFS_FLAG_WRONG_SIGNATURE 0x00000200 /* reserved */ +#define CRAMFS_FLAG_SHIFTED_ROOT_OFFSET 0x00000400 /* shifted root fs */ + +/* + * Valid values in super.flags. Currently we refuse to mount + * if (flags & ~CRAMFS_SUPPORTED_FLAGS). Maybe that should be + * changed to test super.future instead. + */ +#define CRAMFS_SUPPORTED_FLAGS (0xff) + +/* Uncompression interfaces to the underlying zlib */ +int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen); +int cramfs_uncompress_init(void); +int cramfs_uncompress_exit(void); + +uint32_t u32_toggle_endianness(int big_endian, uint32_t what); +void super_toggle_endianness(int from_big_endian, struct cramfs_super *super); +void inode_to_host(int from_big_endian, struct cramfs_inode *inode_in, + struct cramfs_inode *inode_out); +void inode_from_host(int to_big_endian, struct cramfs_inode *inode_in, + struct cramfs_inode *inode_out); + +#endif |