| 1 | /*
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| 2 | * Copyright (c) 2008 Jakub Jermar
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| 3 | * Copyright (c) 2011 Oleg Romanenko
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| 4 | * All rights reserved.
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| 5 | *
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| 6 | * Redistribution and use in source and binary forms, with or without
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| 7 | * modification, are permitted provided that the following conditions
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| 8 | * are met:
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| 9 | *
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| 10 | * - Redistributions of source code must retain the above copyright
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| 11 | * notice, this list of conditions and the following disclaimer.
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| 12 | * - Redistributions in binary form must reproduce the above copyright
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| 13 | * notice, this list of conditions and the following disclaimer in the
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| 14 | * documentation and/or other materials provided with the distribution.
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| 15 | * - The name of the author may not be used to endorse or promote products
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| 16 | * derived from this software without specific prior written permission.
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| 17 | *
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| 18 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 19 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 20 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 21 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 22 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 23 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 24 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 25 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 27 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 28 | */
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| 29 |
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| 30 | /** @addtogroup fs
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| 31 | * @{
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| 32 | */
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| 33 |
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| 34 | #ifndef FAT_FAT_H_
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| 35 | #define FAT_FAT_H_
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| 36 |
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| 37 | #include "fat_fat.h"
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| 38 | #include <fibril_synch.h>
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| 39 | #include <libfs.h>
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| 40 | #include <atomic.h>
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| 41 | #include <stdint.h>
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| 42 | #include <stdbool.h>
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| 43 | #include <macros.h>
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| 44 | #include "../../vfs/vfs.h"
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| 45 |
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| 46 | #ifndef dprintf
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| 47 | #define dprintf(...) printf(__VA_ARGS__)
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| 48 | #endif
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| 49 |
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| 50 | /*
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| 51 | * Convenience macros for accessing some frequently used boot sector members.
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| 52 | */
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| 53 | #define BPS(bs) uint16_t_le2host((bs)->bps)
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| 54 | #define SPC(bs) (bs)->spc
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| 55 | #define RSCNT(bs) uint16_t_le2host((bs)->rscnt)
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| 56 | #define FATCNT(bs) (bs)->fatcnt
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| 57 |
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| 58 | #define SF(bs) (uint16_t_le2host((bs)->sec_per_fat) ? \
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| 59 | uint16_t_le2host((bs)->sec_per_fat) : \
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| 60 | uint32_t_le2host(bs->fat32.sectors_per_fat))
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| 61 |
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| 62 | #define RDE(bs) uint16_t_le2host((bs)->root_ent_max)
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| 63 |
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| 64 | #define TS(bs) (uint16_t_le2host((bs)->totsec16) ? \
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| 65 | uint16_t_le2host((bs)->totsec16) : \
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| 66 | uint32_t_le2host(bs->totsec32))
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| 67 |
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| 68 | #define BS_BLOCK 0
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| 69 | #define BS_SIZE 512
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| 70 |
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| 71 | typedef struct fat_bs {
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| 72 | /** Jump instruction */
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| 73 | uint8_t ji[3];
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| 74 | uint8_t oem_name[8];
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| 75 |
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| 76 | /* BIOS Parameter Block */
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| 77 |
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| 78 | /** Bytes per sector */
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| 79 | uint16_t bps;
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| 80 | /** Sectors per cluster */
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| 81 | uint8_t spc;
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| 82 | /** Reserved sector count */
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| 83 | uint16_t rscnt;
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| 84 | /** Number of FATs */
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| 85 | uint8_t fatcnt;
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| 86 | /** Maximum number of root directory entries */
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| 87 | uint16_t root_ent_max;
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| 88 | /** Total sectors. 16-bit version */
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| 89 | uint16_t totsec16;
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| 90 | /** Media descriptor */
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| 91 | uint8_t mdesc;
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| 92 | /** Sectors per FAT12/FAT16 */
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| 93 | uint16_t sec_per_fat;
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| 94 | /** Sectors per track */
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| 95 | uint16_t sec_per_track;
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| 96 | /** Number of heads */
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| 97 | uint16_t headcnt;
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| 98 | /** Hidden sectors */
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| 99 | uint32_t hidden_sec;
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| 100 | /** Total sectors. 32-bit version */
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| 101 | uint32_t totsec32;
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| 102 |
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| 103 | union {
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| 104 | struct {
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| 105 | /* FAT12/FAT16 only: Extended BIOS Parameter Block */
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| 106 | /** Physical drive number. */
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| 107 | uint8_t pdn;
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| 108 | uint8_t reserved;
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| 109 | /** Extended boot signature. */
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| 110 | uint8_t ebs;
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| 111 | /** Serial number. */
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| 112 | uint32_t id;
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| 113 | /** Volume label. */
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| 114 | uint8_t label[11];
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| 115 | /** FAT type. */
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| 116 | uint8_t type[8];
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| 117 | /** Boot code. */
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| 118 | uint8_t boot_code[448];
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| 119 | /** Boot sector signature. */
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| 120 | uint16_t signature;
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| 121 | } __attribute__((packed));
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| 122 | struct {
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| 123 | /* FAT32 only */
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| 124 | /** Sectors per FAT. */
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| 125 | uint32_t sectors_per_fat;
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| 126 | /** FAT flags. */
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| 127 | uint16_t flags;
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| 128 | /** Version. */
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| 129 | uint16_t version;
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| 130 | /** Cluster number of root directory. */
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| 131 | uint32_t root_cluster;
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| 132 | /** Sector number of file system information sector. */
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| 133 | uint16_t fsinfo_sec;
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| 134 | /** Sector number of boot sector copy. */
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| 135 | uint16_t bscopy_sec;
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| 136 | uint8_t reserved1[12];
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| 137 | /** Physical drive number. */
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| 138 | uint8_t pdn;
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| 139 | uint8_t reserved2;
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| 140 | /** Extended boot signature. */
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| 141 | uint8_t ebs;
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| 142 | /** Serial number. */
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| 143 | uint32_t id;
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| 144 | /** Volume label. */
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| 145 | uint8_t label[11];
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| 146 | /** FAT type. */
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| 147 | uint8_t type[8];
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| 148 | /** Boot code. */
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| 149 | uint8_t boot_code[420];
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| 150 | /** Signature. */
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| 151 | uint16_t signature;
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| 152 | } __attribute__((packed)) fat32;
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| 153 | };
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| 154 | } __attribute__((packed)) fat_bs_t;
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| 155 |
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| 156 | #define FAT32_FSINFO_SIG1 "RRaA"
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| 157 | #define FAT32_FSINFO_SIG2 "rrAa"
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| 158 | #define FAT32_FSINFO_SIG3 "\x00\x00\x55\xaa"
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| 159 |
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| 160 | typedef struct {
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| 161 | uint8_t sig1[4];
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| 162 | uint8_t res1[480];
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| 163 | uint8_t sig2[4];
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| 164 | uint32_t free_clusters;
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| 165 | uint32_t last_allocated_cluster;
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| 166 | uint8_t res2[12];
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| 167 | uint8_t sig3[4];
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| 168 | } __attribute__((packed)) fat32_fsinfo_t;
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| 169 |
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| 170 | typedef enum {
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| 171 | FAT_INVALID,
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| 172 | FAT_DIRECTORY,
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| 173 | FAT_FILE
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| 174 | } fat_node_type_t;
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| 175 |
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| 176 | struct fat_node;
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| 177 |
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| 178 | /** FAT index structure.
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| 179 | *
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| 180 | * This structure exists to help us to overcome certain limitations of the FAT
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| 181 | * file system design. The problem with FAT is that it is hard to find
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| 182 | * an entity which could represent a VFS index. There are two candidates:
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| 183 | *
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| 184 | * a) number of the node's first cluster
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| 185 | * b) the pair of the parent directory's first cluster and the dentry index
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| 186 | * within the parent directory
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| 187 | *
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| 188 | * We need VFS indices to be:
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| 189 | * A) unique
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| 190 | * B) stable in time, at least until the next mount
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| 191 | *
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| 192 | * Unfortunately a) does not meet the A) criterion because zero-length files
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| 193 | * will have the first cluster field cleared. And b) does not meet the B)
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| 194 | * criterion because unlink() and rename() will both free up the original
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| 195 | * dentry, which contains all the essential info about the file.
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| 196 | *
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| 197 | * Therefore, a completely opaque indices are used and the FAT server maintains
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| 198 | * a mapping between them and otherwise nice b) variant. On rename(), the VFS
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| 199 | * index stays unaltered, while the internal FAT "physical tree address"
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| 200 | * changes. The unlink case is also handled this way thanks to an in-core node
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| 201 | * pointer embedded in the index structure.
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| 202 | */
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| 203 | typedef struct {
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| 204 | /** Used indices (position) hash table link. */
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| 205 | ht_link_t uph_link;
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| 206 | /** Used indices (index) hash table link. */
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| 207 | ht_link_t uih_link;
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| 208 |
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| 209 | fibril_mutex_t lock;
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| 210 | service_id_t service_id;
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| 211 | fs_index_t index;
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| 212 | /**
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| 213 | * Parent node's first cluster.
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| 214 | * Zero is used if this node is not linked, in which case nodep must
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| 215 | * contain a pointer to the in-core node structure.
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| 216 | * One is used when the parent is the root directory.
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| 217 | */
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| 218 | fat_cluster_t pfc;
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| 219 | /** Directory entry index within the parent node. */
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| 220 | unsigned pdi;
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| 221 | /** Pointer to in-core node instance. */
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| 222 | struct fat_node *nodep;
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| 223 | } fat_idx_t;
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| 224 |
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| 225 | /** FAT in-core node. */
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| 226 | typedef struct fat_node {
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| 227 | /** Back pointer to the FS node. */
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| 228 | fs_node_t *bp;
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| 229 |
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| 230 | fibril_mutex_t lock;
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| 231 | fat_node_type_t type;
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| 232 | fat_idx_t *idx;
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| 233 | /**
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| 234 | * Node's first cluster.
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| 235 | * Zero is used for zero-length nodes.
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| 236 | * One is used to mark root directory.
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| 237 | */
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| 238 | fat_cluster_t firstc;
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| 239 | /** FAT in-core node free list link. */
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| 240 | link_t ffn_link;
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| 241 | aoff64_t size;
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| 242 | unsigned lnkcnt;
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| 243 | unsigned refcnt;
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| 244 | bool dirty;
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| 245 |
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| 246 | /*
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| 247 | * Cache of the node's last and "current" cluster to avoid some
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| 248 | * unnecessary FAT walks.
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| 249 | */
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| 250 | /* Node's last cluster in FAT. */
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| 251 | bool lastc_cached_valid;
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| 252 | fat_cluster_t lastc_cached_value;
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| 253 | /* Node's "current" cluster, i.e. where the last I/O took place. */
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| 254 | bool currc_cached_valid;
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| 255 | aoff64_t currc_cached_bn;
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| 256 | fat_cluster_t currc_cached_value;
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| 257 | } fat_node_t;
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| 258 |
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| 259 | typedef struct {
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| 260 | bool lfn_enabled;
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| 261 | } fat_instance_t;
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| 262 |
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| 263 | extern vfs_out_ops_t fat_ops;
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| 264 | extern libfs_ops_t fat_libfs_ops;
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| 265 |
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| 266 | extern errno_t fat_idx_get_new(fat_idx_t **, service_id_t);
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| 267 | extern fat_idx_t *fat_idx_get_by_pos(service_id_t, fat_cluster_t, unsigned);
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| 268 | extern fat_idx_t *fat_idx_get_by_index(service_id_t, fs_index_t);
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| 269 | extern void fat_idx_destroy(fat_idx_t *);
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| 270 | extern void fat_idx_hashin(fat_idx_t *);
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| 271 | extern void fat_idx_hashout(fat_idx_t *);
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| 272 |
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| 273 | extern errno_t fat_idx_init(void);
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| 274 | extern void fat_idx_fini(void);
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| 275 | extern errno_t fat_idx_init_by_service_id(service_id_t);
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| 276 | extern void fat_idx_fini_by_service_id(service_id_t);
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| 277 |
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| 278 | #endif
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| 279 |
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| 280 | /**
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| 281 | * @}
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| 282 | */
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