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2627 | jermar | 1 | /* |
2789 | jermar | 2 | * Copyright (c) 2008 Jakub Jermar |
2627 | jermar | 3 | * All rights reserved. |
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 | |||
3535 | svoboda | 36 | #include "fat_fat.h" |
2627 | jermar | 37 | #include <ipc/ipc.h> |
2643 | jermar | 38 | #include <libfs.h> |
2627 | jermar | 39 | #include <atomic.h> |
40 | #include <sys/types.h> |
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41 | #include <bool.h> |
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2789 | jermar | 42 | #include "../../vfs/vfs.h" |
2627 | jermar | 43 | |
3153 | svoboda | 44 | #ifndef dprintf |
2627 | jermar | 45 | #define dprintf(...) printf(__VA_ARGS__) |
3153 | svoboda | 46 | #endif |
2627 | jermar | 47 | |
3535 | svoboda | 48 | #define min(a, b) ((a) < (b) ? (a) : (b)) |
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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2628 | jermar | 54 | uint8_t ji[3]; /**< Jump instruction. */ |
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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2789 | jermar | 59 | uint16_t rscnt; /**< Reserved sector count. */ |
2628 | jermar | 60 | uint8_t fatcnt; /**< Number of FATs. */ |
61 | uint16_t root_ent_max; /**< Maximum number of root directory |
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62 | entries. */ |
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2789 | jermar | 63 | uint16_t totsec16; /**< Total sectors. 16-bit version. */ |
2628 | jermar | 64 | uint8_t mdesc; /**< Media descriptor. */ |
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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2831 | jermar | 69 | uint32_t totsec32; /**< Total sectors. 32-bit version. */ |
2628 | jermar | 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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2789 | jermar | 113 | uint8_t label[11]; |
2628 | jermar | 114 | /** FAT type. */ |
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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2629 | jermar | 122 | } __attribute__ ((packed)) fat_bs_t; |
2628 | jermar | 123 | |
2789 | jermar | 124 | typedef enum { |
2831 | jermar | 125 | FAT_INVALID, |
2789 | jermar | 126 | FAT_DIRECTORY, |
127 | FAT_FILE |
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128 | } fat_node_type_t; |
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129 | |||
2864 | jermar | 130 | struct fat_node; |
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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2890 | jermar | 158 | /** Used indices (position) hash table link. */ |
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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2889 | jermar | 162 | |
3009 | svoboda | 163 | futex_t lock; |
2864 | jermar | 164 | dev_handle_t dev_handle; |
165 | fs_index_t index; |
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166 | /** |
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2889 | jermar | 167 | * Parent node's first cluster. |
2864 | jermar | 168 | * Zero is used if this node is not linked, in which case nodep must |
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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2889 | jermar | 173 | /** Directory entry index within the parent node. */ |
2864 | jermar | 174 | unsigned pdi; |
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 | |||
2789 | jermar | 179 | /** FAT in-core node. */ |
2864 | jermar | 180 | typedef struct fat_node { |
3009 | svoboda | 181 | futex_t lock; |
2789 | jermar | 182 | fat_node_type_t type; |
2864 | jermar | 183 | fat_idx_t *idx; |
184 | /** |
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185 | * Node's first cluster. |
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186 | * Zero is used for zero-length nodes. |
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187 | * One is used to mark root directory. |
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188 | */ |
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189 | fat_cluster_t firstc; |
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2831 | jermar | 190 | /** FAT in-core node free list link. */ |
191 | link_t ffn_link; |
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2789 | jermar | 192 | size_t size; |
193 | unsigned lnkcnt; |
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2831 | jermar | 194 | unsigned refcnt; |
195 | bool dirty; |
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2789 | jermar | 196 | } fat_node_t; |
197 | |||
2643 | jermar | 198 | extern fs_reg_t fat_reg; |
2627 | jermar | 199 | |
3153 | svoboda | 200 | extern void fat_mounted(ipc_callid_t, ipc_call_t *); |
201 | extern void fat_mount(ipc_callid_t, ipc_call_t *); |
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2638 | jermar | 202 | extern void fat_lookup(ipc_callid_t, ipc_call_t *); |
3403 | svoboda | 203 | extern void fat_read(ipc_callid_t, ipc_call_t *); |
3535 | svoboda | 204 | extern void fat_write(ipc_callid_t, ipc_call_t *); |
2638 | jermar | 205 | |
2890 | jermar | 206 | extern fat_idx_t *fat_idx_get_by_pos(dev_handle_t, fat_cluster_t, unsigned); |
207 | extern fat_idx_t *fat_idx_get_by_index(dev_handle_t, fs_index_t); |
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2876 | jermar | 208 | |
3153 | svoboda | 209 | extern int fat_idx_init(void); |
210 | extern void fat_idx_fini(void); |
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211 | extern int fat_idx_init_by_dev_handle(dev_handle_t); |
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212 | extern void fat_idx_fini_by_dev_handle(dev_handle_t); |
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213 | |||
2627 | jermar | 214 | #endif |
215 | |||
216 | /** |
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217 | * @} |
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218 | */ |