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| 4419 | trochtova | 1 | /* |
| 2 | * Copyright (c) 2008 Jakub Jermar |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 29 | /** @addtogroup fs |
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| 30 | * @{ |
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| 31 | */ |
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| 32 | |||
| 33 | #ifndef FAT_FAT_H_ |
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| 34 | #define FAT_FAT_H_ |
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| 35 | |||
| 36 | #include "fat_fat.h" |
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| 37 | #include <ipc/ipc.h> |
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| 38 | #include <libfs.h> |
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| 39 | #include <atomic.h> |
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| 40 | #include <sys/types.h> |
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| 41 | #include <bool.h> |
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| 42 | #include "../../vfs/vfs.h" |
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| 43 | |||
| 44 | #ifndef dprintf |
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| 45 | #define dprintf(...) printf(__VA_ARGS__) |
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| 46 | #endif |
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| 47 | |||
| 48 | #define min(a, b) ((a) < (b) ? (a) : (b)) |
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| 49 | |||
| 50 | #define BS_BLOCK 0 |
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| 51 | #define BS_SIZE 512 |
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| 52 | |||
| 53 | typedef struct fat_bs { |
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| 54 | uint8_t ji[3]; /**< Jump instruction. */ |
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| 55 | uint8_t oem_name[8]; |
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| 56 | /* BIOS Parameter Block */ |
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| 57 | uint16_t bps; /**< Bytes per sector. */ |
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| 58 | uint8_t spc; /**< Sectors per cluster. */ |
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| 59 | uint16_t rscnt; /**< Reserved sector count. */ |
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| 60 | uint8_t fatcnt; /**< Number of FATs. */ |
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| 61 | uint16_t root_ent_max; /**< Maximum number of root directory |
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| 62 | entries. */ |
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| 63 | uint16_t totsec16; /**< Total sectors. 16-bit version. */ |
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| 64 | uint8_t mdesc; /**< Media descriptor. */ |
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| 65 | uint16_t sec_per_fat; /**< Sectors per FAT12/FAT16. */ |
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| 66 | uint16_t sec_per_track; /**< Sectors per track. */ |
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| 67 | uint16_t headcnt; /**< Number of heads. */ |
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| 68 | uint32_t hidden_sec; /**< Hidden sectors. */ |
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| 69 | uint32_t totsec32; /**< Total sectors. 32-bit version. */ |
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| 70 | |||
| 71 | union { |
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| 72 | struct { |
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| 73 | /* FAT12/FAT16 only: Extended BIOS Parameter Block */ |
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| 74 | /** Physical drive number. */ |
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| 75 | uint8_t pdn; |
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| 76 | uint8_t reserved; |
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| 77 | /** Extended boot signature. */ |
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| 78 | uint8_t ebs; |
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| 79 | /** Serial number. */ |
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| 80 | uint32_t id; |
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| 81 | /** Volume label. */ |
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| 82 | uint8_t label[11]; |
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| 83 | /** FAT type. */ |
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| 84 | uint8_t type[8]; |
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| 85 | /** Boot code. */ |
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| 86 | uint8_t boot_code[448]; |
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| 87 | /** Boot sector signature. */ |
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| 88 | uint16_t signature; |
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| 89 | } __attribute__ ((packed)); |
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| 90 | struct { |
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| 91 | /* FAT32 only */ |
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| 92 | /** Sectors per FAT. */ |
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| 93 | uint32_t sectors_per_fat; |
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| 94 | /** FAT flags. */ |
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| 95 | uint16_t flags; |
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| 96 | /** Version. */ |
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| 97 | uint16_t version; |
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| 98 | /** Cluster number of root directory. */ |
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| 99 | uint32_t root_cluster; |
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| 100 | /** Sector number of file system information sector. */ |
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| 101 | uint16_t fsinfo_sec; |
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| 102 | /** Sector number of boot sector copy. */ |
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| 103 | uint16_t bscopy_sec; |
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| 104 | uint8_t reserved1[12]; |
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| 105 | /** Physical drive number. */ |
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| 106 | uint8_t pdn; |
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| 107 | uint8_t reserved2; |
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| 108 | /** Extended boot signature. */ |
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| 109 | uint8_t ebs; |
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| 110 | /** Serial number. */ |
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| 111 | uint32_t id; |
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| 112 | /** Volume label. */ |
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| 113 | uint8_t label[11]; |
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| 114 | /** FAT type. */ |
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| 115 | uint8_t type[8]; |
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| 116 | /** Boot code. */ |
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| 117 | uint8_t boot_code[420]; |
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| 118 | /** Signature. */ |
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| 119 | uint16_t signature; |
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| 120 | } __attribute__ ((packed)); |
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| 121 | }; |
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| 122 | } __attribute__ ((packed)) fat_bs_t; |
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| 123 | |||
| 124 | typedef enum { |
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| 125 | FAT_INVALID, |
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| 126 | FAT_DIRECTORY, |
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| 127 | FAT_FILE |
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| 128 | } fat_node_type_t; |
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| 129 | |||
| 130 | struct fat_node; |
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| 131 | |||
| 132 | /** FAT index structure. |
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| 133 | * |
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| 134 | * This structure exists to help us to overcome certain limitations of the FAT |
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| 135 | * file system design. The problem with FAT is that it is hard to find |
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| 136 | * an entity which could represent a VFS index. There are two candidates: |
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| 137 | * |
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| 138 | * a) number of the node's first cluster |
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| 139 | * b) the pair of the parent directory's first cluster and the dentry index |
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| 140 | * within the parent directory |
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| 141 | * |
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| 142 | * We need VFS indices to be: |
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| 143 | * A) unique |
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| 144 | * B) stable in time, at least until the next mount |
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| 145 | * |
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| 146 | * Unfortunately a) does not meet the A) criterion because zero-length files |
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| 147 | * will have the first cluster field cleared. And b) does not meet the B) |
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| 148 | * criterion because unlink() and rename() will both free up the original |
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| 149 | * dentry, which contains all the essential info about the file. |
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| 150 | * |
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| 151 | * Therefore, a completely opaque indices are used and the FAT server maintains |
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| 152 | * a mapping between them and otherwise nice b) variant. On rename(), the VFS |
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| 153 | * index stays unaltered, while the internal FAT "physical tree address" |
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| 154 | * changes. The unlink case is also handled this way thanks to an in-core node |
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| 155 | * pointer embedded in the index structure. |
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| 156 | */ |
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| 157 | typedef struct { |
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| 158 | /** Used indices (position) hash table link. */ |
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| 159 | link_t uph_link; |
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| 160 | /** Used indices (index) hash table link. */ |
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| 161 | link_t uih_link; |
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| 162 | |||
| 163 | futex_t lock; |
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| 164 | dev_handle_t dev_handle; |
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| 165 | fs_index_t index; |
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| 166 | /** |
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| 167 | * Parent node's first cluster. |
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| 168 | * Zero is used if this node is not linked, in which case nodep must |
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| 169 | * contain a pointer to the in-core node structure. |
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| 170 | * One is used when the parent is the root directory. |
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| 171 | */ |
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| 172 | fat_cluster_t pfc; |
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| 173 | /** Directory entry index within the parent node. */ |
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| 174 | unsigned pdi; |
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| 175 | /** Pointer to in-core node instance. */ |
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| 176 | struct fat_node *nodep; |
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| 177 | } fat_idx_t; |
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| 178 | |||
| 179 | /** FAT in-core node. */ |
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| 180 | typedef struct fat_node { |
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| 4420 | trochtova | 181 | /** Back pointer to the FS node. */ |
| 182 | fs_node_t *bp; |
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| 183 | |||
| 4419 | trochtova | 184 | futex_t lock; |
| 185 | fat_node_type_t type; |
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| 186 | fat_idx_t *idx; |
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| 187 | /** |
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| 188 | * Node's first cluster. |
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| 189 | * Zero is used for zero-length nodes. |
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| 190 | * One is used to mark root directory. |
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| 191 | */ |
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| 192 | fat_cluster_t firstc; |
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| 193 | /** FAT in-core node free list link. */ |
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| 194 | link_t ffn_link; |
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| 195 | size_t size; |
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| 196 | unsigned lnkcnt; |
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| 197 | unsigned refcnt; |
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| 198 | bool dirty; |
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| 199 | } fat_node_t; |
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| 200 | |||
| 201 | extern fs_reg_t fat_reg; |
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| 202 | |||
| 203 | extern void fat_mounted(ipc_callid_t, ipc_call_t *); |
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| 204 | extern void fat_mount(ipc_callid_t, ipc_call_t *); |
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| 205 | extern void fat_lookup(ipc_callid_t, ipc_call_t *); |
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| 206 | extern void fat_read(ipc_callid_t, ipc_call_t *); |
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| 207 | extern void fat_write(ipc_callid_t, ipc_call_t *); |
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| 208 | extern void fat_truncate(ipc_callid_t, ipc_call_t *); |
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| 209 | extern void fat_destroy(ipc_callid_t, ipc_call_t *); |
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| 210 | |||
| 211 | extern fat_idx_t *fat_idx_get_new(dev_handle_t); |
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| 212 | extern fat_idx_t *fat_idx_get_by_pos(dev_handle_t, fat_cluster_t, unsigned); |
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| 213 | extern fat_idx_t *fat_idx_get_by_index(dev_handle_t, fs_index_t); |
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| 214 | extern void fat_idx_destroy(fat_idx_t *); |
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| 215 | extern void fat_idx_hashin(fat_idx_t *); |
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| 216 | extern void fat_idx_hashout(fat_idx_t *); |
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| 217 | |||
| 218 | extern int fat_idx_init(void); |
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| 219 | extern void fat_idx_fini(void); |
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| 220 | extern int fat_idx_init_by_dev_handle(dev_handle_t); |
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| 221 | extern void fat_idx_fini_by_dev_handle(dev_handle_t); |
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| 222 | |||
| 223 | #endif |
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| 224 | |||
| 225 | /** |
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| 226 | * @} |
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| 227 | */ |