1/* 2 * Copyright (c) 2000-2012 Apple Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28 29#ifndef _FSCK_JOURNAL_H 30#define _FSCK_JOURNAL_H 31 32#include <sys/cdefs.h> 33 34#include <sys/types.h> 35 36/* 37 * The guts of the journal: a descriptor for which 38 * block number on the data disk is to be written. 39 */ 40typedef struct block_info { 41 uint64_t bnum; 42 uint32_t bsize; 43 uint32_t next; 44} __attribute__((__packed__)) block_info; 45 46/* 47 * A "transaction," for want of a better word. 48 * This contains a series of block_info, in the 49 * binfo array, which are used to modify the 50 * filesystem. 51 */ 52typedef struct block_list_header { 53 uint16_t max_blocks; 54 uint16_t num_blocks; 55 uint32_t bytes_used; 56 uint32_t checksum; 57 uint32_t pad; 58 block_info binfo[1]; 59} __attribute__((__packed__)) block_list_header; 60 61/* 62 * This is written to block zero of the journal and it 63 * maintains overall state about the journal. 64 */ 65typedef struct journal_header { 66 int32_t magic; 67 int32_t endian; 68 off_t start; // zero-based byte offset of the start of the first transaction 69 off_t end; // zero-based byte offset of where free space begins 70 off_t size; // size in bytes of the entire journal 71 int32_t blhdr_size; // size in bytes of each block_list_header in the journal 72 int32_t checksum; 73 int32_t jhdr_size; // block size (in bytes) of the journal header 74 uint32_t sequence_num; // NEW FIELD: a monotonically increasing value assigned to all txn's 75} __attribute__((__packed__)) journal_header; 76 77#define JOURNAL_HEADER_MAGIC 0x4a4e4c78 // 'JNLx' 78#define OLD_JOURNAL_HEADER_MAGIC 0x4a484452 // 'JHDR' 79#define ENDIAN_MAGIC 0x12345678 80 81// 82// we only checksum the original size of the journal_header to remain 83// backwards compatible. the size of the original journal_header is 84// everything up to the the sequence_num field, hence we use the 85// offsetof macro to calculate the size. 86// 87#define JOURNAL_HEADER_CKSUM_SIZE (offsetof(struct journal_header, sequence_num)) 88 89#define OLD_JOURNAL_HEADER_MAGIC 0x4a484452 // 'JHDR' 90 91/* 92 * The function used by fsck_hfs to replay the journal. 93 * It's modeled on the kernel function. 94 * 95 * For the do_write_b block, the offset argument is in bytes -- 96 * the journal replay code will convert from journal block to 97 * bytes. 98 */ 99 100int journal_open(int jdev, 101 off_t offset, 102 off_t journal_size, 103 size_t min_fs_block_size, 104 uint32_t flags, 105 const char *jdev_name, 106 int (^do_write_b)(off_t, void *, size_t)); 107 108#endif /* !_FSCK_JOURNAL_H */ 109