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2627 | jermar | 1 | /* |
2793 | 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 | /** |
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34 | * @file fat_ops.c |
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35 | * @brief Implementation of VFS operations for the FAT file system server. |
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36 | */ |
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37 | |||
38 | #include "fat.h" |
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2638 | jermar | 39 | #include "../../vfs/vfs.h" |
2793 | jermar | 40 | #include <libfs.h> |
2627 | jermar | 41 | #include <ipc/ipc.h> |
42 | #include <async.h> |
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43 | #include <errno.h> |
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2793 | jermar | 44 | #include <string.h> |
2798 | jermar | 45 | #include <byteorder.h> |
2831 | jermar | 46 | #include <libadt/hash_table.h> |
47 | #include <libadt/list.h> |
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48 | #include <assert.h> |
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2856 | jermar | 49 | #include <futex.h> |
2627 | jermar | 50 | |
2843 | jermar | 51 | #define BS_BLOCK 0 |
52 | |||
53 | #define FIN_KEY_DEV_HANDLE 0 |
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54 | #define FIN_KEY_INDEX 1 |
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55 | |||
2856 | jermar | 56 | /** Futex protecting both fin_hash and ffn_head. */ |
57 | futex_t fin_futex = FUTEX_INITIALIZER; |
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58 | |||
2831 | jermar | 59 | /** Hash table of FAT in-core nodes. */ |
60 | hash_table_t fin_hash; |
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61 | |||
62 | /** List of free FAT in-core nodes. */ |
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63 | link_t ffn_head; |
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64 | |||
2638 | jermar | 65 | #define FAT_NAME_LEN 8 |
66 | #define FAT_EXT_LEN 3 |
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67 | |||
68 | #define FAT_PAD ' ' |
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69 | |||
70 | #define FAT_DENTRY_UNUSED 0x00 |
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71 | #define FAT_DENTRY_E5_ESC 0x05 |
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72 | #define FAT_DENTRY_DOT 0x2e |
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73 | #define FAT_DENTRY_ERASED 0xe5 |
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74 | |||
2793 | jermar | 75 | static void dentry_name_canonify(fat_dentry_t *d, char *buf) |
2638 | jermar | 76 | { |
2793 | jermar | 77 | int i; |
2639 | jermar | 78 | |
2793 | jermar | 79 | for (i = 0; i < FAT_NAME_LEN; i++) { |
80 | if (d->name[i] == FAT_PAD) { |
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81 | buf++; |
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82 | break; |
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2639 | jermar | 83 | } |
2793 | jermar | 84 | if (d->name[i] == FAT_DENTRY_E5_ESC) |
85 | *buf++ = 0xe5; |
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86 | else |
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87 | *buf++ = d->name[i]; |
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88 | } |
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89 | if (d->ext[0] != FAT_PAD) |
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90 | *buf++ = '.'; |
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91 | for (i = 0; i < FAT_EXT_LEN; i++) { |
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92 | if (d->ext[i] == FAT_PAD) { |
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93 | *buf = '\0'; |
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94 | return; |
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95 | } |
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96 | if (d->ext[i] == FAT_DENTRY_E5_ESC) |
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97 | *buf++ = 0xe5; |
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98 | else |
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99 | *buf++ = d->ext[i]; |
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100 | } |
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101 | } |
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102 | |||
2822 | jermar | 103 | /* TODO and also move somewhere else */ |
104 | typedef struct { |
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105 | void *data; |
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106 | } block_t; |
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107 | |||
108 | static block_t *block_get(dev_handle_t dev_handle, off_t offset) |
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2793 | jermar | 109 | { |
110 | return NULL; /* TODO */ |
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111 | } |
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112 | |||
2822 | jermar | 113 | static void block_put(block_t *block) |
2793 | jermar | 114 | { |
115 | /* TODO */ |
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116 | } |
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117 | |||
2859 | jermar | 118 | |
119 | #define FAT_BS(b) ((fat_bs_t *)((b)->data)) |
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120 | |||
121 | #define FAT_CLST_FIRST 0x0002 |
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122 | #define FAT_CLST_BAD 0xfff7 |
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123 | #define FAT_CLST_LAST1 0xfff8 |
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124 | #define FAT_CLST_LAST8 0xffff |
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125 | |||
126 | /** Convert cluster number to an index within a FAT. |
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127 | * |
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128 | * Format Identifier and cluster numbering is considered. |
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129 | */ |
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130 | #define C2FAT_IDX(c) (1 + (c) - FAT_CLST_FIRST) |
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131 | |||
132 | static block_t *fat_block_get(dev_handle_t dev_handle, fs_index_t index, |
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133 | off_t offset) |
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134 | { |
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135 | block_t *bb; |
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136 | block_t *b; |
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137 | unsigned bps; |
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138 | unsigned spc; |
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139 | unsigned rscnt; /* block address of the first FAT */ |
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140 | unsigned fatcnt; |
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141 | unsigned rde; |
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142 | unsigned rds; /* root directory size */ |
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143 | unsigned sf; |
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144 | unsigned ssa; /* size of the system area */ |
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145 | unsigned clusters; |
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146 | unsigned clst = index; |
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147 | unsigned i; |
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148 | |||
149 | bb = block_get(dev_handle, BS_BLOCK); |
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150 | bps = uint16_t_le2host(FAT_BS(bb)->bps); |
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151 | spc = FAT_BS(bb)->spc; |
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152 | rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt); |
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153 | fatcnt = FAT_BS(bb)->fatcnt; |
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154 | rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max); |
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155 | sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat); |
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156 | block_put(bb); |
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157 | |||
158 | rds = (sizeof(fat_dentry_t) * rde) / bps; |
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159 | rds += ((sizeof(fat_dentry_t) * rde) % bps != 0); |
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160 | ssa = rscnt + fatcnt * sf + rds; |
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161 | |||
162 | if (!index) { |
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163 | /* root directory special case */ |
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164 | assert(offset < rds); |
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165 | b = block_get(dev_handle, rscnt + fatcnt * sf + offset); |
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166 | return b; |
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167 | } |
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168 | |||
169 | clusters = offset / spc; |
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170 | for (i = 0; i < clusters; i++) { |
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171 | unsigned fsec; /* sector offset relative to FAT1 */ |
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172 | unsigned fidx; /* FAT1 entry index */ |
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173 | |||
174 | assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD); |
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175 | fsec = (C2FAT_IDX(clst) * sizeof(uint16_t)) / bps; |
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176 | fidx = C2FAT_IDX(clst) % (bps / sizeof(uint16_t)); |
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177 | /* read FAT1 */ |
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178 | b = block_get(dev_handle, rscnt + fsec); |
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179 | clst = uint16_t_le2host(((uint16_t *)b->data)[fidx]); |
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180 | assert(clst != FAT_CLST_BAD); |
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181 | assert(clst < FAT_CLST_LAST1); |
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182 | block_put(b); |
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183 | } |
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184 | |||
185 | b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc + |
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186 | offset % spc); |
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187 | |||
188 | return b; |
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189 | } |
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190 | |||
2831 | jermar | 191 | static void fat_node_initialize(fat_node_t *node) |
2793 | jermar | 192 | { |
2856 | jermar | 193 | futex_initialize(&node->lock, 1); |
2831 | jermar | 194 | node->type = 0; |
195 | node->index = 0; |
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196 | node->pindex = 0; |
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197 | node->dev_handle = 0; |
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198 | link_initialize(&node->fin_link); |
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199 | link_initialize(&node->ffn_link); |
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200 | node->size = 0; |
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201 | node->lnkcnt = 0; |
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202 | node->refcnt = 0; |
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203 | node->dirty = false; |
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2793 | jermar | 204 | } |
205 | |||
2843 | jermar | 206 | static uint16_t fat_bps_get(dev_handle_t dev_handle) |
207 | { |
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208 | block_t *bb; |
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209 | uint16_t bps; |
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210 | |||
211 | bb = block_get(dev_handle, BS_BLOCK); |
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212 | assert(bb != NULL); |
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2859 | jermar | 213 | bps = uint16_t_le2host(FAT_BS(bb)->bps); |
2843 | jermar | 214 | block_put(bb); |
215 | |||
216 | return bps; |
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217 | } |
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218 | |||
2845 | jermar | 219 | typedef enum { |
220 | FAT_DENTRY_SKIP, |
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221 | FAT_DENTRY_LAST, |
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222 | FAT_DENTRY_VALID |
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223 | } fat_dentry_clsf_t; |
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224 | |||
225 | static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d) |
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226 | { |
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227 | if (d->attr & FAT_ATTR_VOLLABEL) { |
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228 | /* volume label entry */ |
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229 | return FAT_DENTRY_SKIP; |
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230 | } |
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231 | if (d->name[0] == FAT_DENTRY_ERASED) { |
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232 | /* not-currently-used entry */ |
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233 | return FAT_DENTRY_SKIP; |
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234 | } |
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235 | if (d->name[0] == FAT_DENTRY_UNUSED) { |
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236 | /* never used entry */ |
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237 | return FAT_DENTRY_LAST; |
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238 | } |
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239 | if (d->name[0] == FAT_DENTRY_DOT) { |
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240 | /* |
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241 | * Most likely '.' or '..'. |
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242 | * It cannot occur in a regular file name. |
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243 | */ |
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244 | return FAT_DENTRY_SKIP; |
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245 | } |
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246 | return FAT_DENTRY_VALID; |
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247 | } |
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248 | |||
2831 | jermar | 249 | static void fat_sync_node(fat_node_t *node) |
250 | { |
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251 | /* TODO */ |
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252 | } |
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253 | |||
2863 | jermar | 254 | /** Instantiate a FAT in-core node. */ |
2831 | jermar | 255 | static void * |
2863 | jermar | 256 | fat_node_get(dev_handle_t dev_handle, fs_index_t index) |
2831 | jermar | 257 | { |
2863 | jermar | 258 | return NULL; /* TODO */ |
2831 | jermar | 259 | } |
260 | |||
2852 | jermar | 261 | static void fat_node_put(void *node) |
262 | { |
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2863 | jermar | 263 | /* TODO */ |
2852 | jermar | 264 | } |
265 | |||
2857 | jermar | 266 | static void *fat_create(int flags) |
267 | { |
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268 | return NULL; /* not supported at the moment */ |
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269 | } |
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270 | |||
2858 | jermar | 271 | static int fat_destroy(void *node) |
2857 | jermar | 272 | { |
2858 | jermar | 273 | return ENOTSUP; /* not supported at the moment */ |
2857 | jermar | 274 | } |
275 | |||
276 | static bool fat_link(void *prnt, void *chld, const char *name) |
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277 | { |
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278 | return false; /* not supported at the moment */ |
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279 | } |
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280 | |||
281 | static int fat_unlink(void *prnt, void *chld) |
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282 | { |
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283 | return ENOTSUP; /* not supported at the moment */ |
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284 | } |
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285 | |||
2793 | jermar | 286 | static void *fat_match(void *prnt, const char *component) |
287 | { |
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288 | fat_node_t *parentp = (fat_node_t *)prnt; |
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289 | char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1]; |
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2822 | jermar | 290 | unsigned i, j; |
2828 | jermar | 291 | unsigned bps; /* bytes per sector */ |
2822 | jermar | 292 | unsigned dps; /* dentries per sector */ |
293 | unsigned blocks; |
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2793 | jermar | 294 | fat_dentry_t *d; |
2822 | jermar | 295 | block_t *b; |
2793 | jermar | 296 | |
2843 | jermar | 297 | bps = fat_bps_get(parentp->dev_handle); |
2828 | jermar | 298 | dps = bps / sizeof(fat_dentry_t); |
299 | blocks = parentp->size / bps + (parentp->size % bps != 0); |
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2822 | jermar | 300 | for (i = 0; i < blocks; i++) { |
301 | unsigned dentries; |
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2793 | jermar | 302 | |
2831 | jermar | 303 | b = fat_block_get(parentp->dev_handle, parentp->index, i); |
2822 | jermar | 304 | dentries = (i == blocks - 1) ? |
305 | parentp->size % sizeof(fat_dentry_t) : |
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306 | dps; |
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307 | for (j = 0; j < dentries; j++) { |
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308 | d = ((fat_dentry_t *)b->data) + j; |
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2845 | jermar | 309 | switch (fat_classify_dentry(d)) { |
310 | case FAT_DENTRY_SKIP: |
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2822 | jermar | 311 | continue; |
2845 | jermar | 312 | case FAT_DENTRY_LAST: |
2822 | jermar | 313 | block_put(b); |
314 | return NULL; |
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2845 | jermar | 315 | default: |
316 | case FAT_DENTRY_VALID: |
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317 | dentry_name_canonify(d, name); |
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318 | break; |
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2822 | jermar | 319 | } |
320 | if (strcmp(name, component) == 0) { |
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321 | /* hit */ |
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322 | void *node = fat_node_get(parentp->dev_handle, |
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2863 | jermar | 323 | (fs_index_t)uint16_t_le2host(d->firstc)); |
2822 | jermar | 324 | block_put(b); |
325 | return node; |
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326 | } |
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2793 | jermar | 327 | } |
2822 | jermar | 328 | block_put(b); |
2639 | jermar | 329 | } |
2793 | jermar | 330 | |
331 | return NULL; |
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2638 | jermar | 332 | } |
333 | |||
2831 | jermar | 334 | static fs_index_t fat_index_get(void *node) |
335 | { |
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336 | fat_node_t *fnodep = (fat_node_t *)node; |
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337 | if (!fnodep) |
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338 | return 0; |
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339 | return fnodep->index; |
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340 | } |
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341 | |||
342 | static size_t fat_size_get(void *node) |
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343 | { |
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344 | return ((fat_node_t *)node)->size; |
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345 | } |
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346 | |||
347 | static unsigned fat_lnkcnt_get(void *node) |
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348 | { |
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349 | return ((fat_node_t *)node)->lnkcnt; |
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350 | } |
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351 | |||
2845 | jermar | 352 | static bool fat_has_children(void *node) |
353 | { |
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354 | fat_node_t *nodep = (fat_node_t *)node; |
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355 | unsigned bps; |
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356 | unsigned dps; |
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357 | unsigned blocks; |
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358 | block_t *b; |
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359 | unsigned i, j; |
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360 | |||
361 | if (nodep->type != FAT_DIRECTORY) |
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362 | return false; |
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363 | |||
364 | bps = fat_bps_get(nodep->dev_handle); |
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365 | dps = bps / sizeof(fat_dentry_t); |
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366 | |||
367 | blocks = nodep->size / bps + (nodep->size % bps != 0); |
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368 | |||
369 | for (i = 0; i < blocks; i++) { |
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370 | unsigned dentries; |
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371 | fat_dentry_t *d; |
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372 | |||
373 | b = fat_block_get(nodep->dev_handle, nodep->index, i); |
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374 | dentries = (i == blocks - 1) ? |
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375 | nodep->size % sizeof(fat_dentry_t) : |
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376 | dps; |
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377 | for (j = 0; j < dentries; j++) { |
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378 | d = ((fat_dentry_t *)b->data) + j; |
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379 | switch (fat_classify_dentry(d)) { |
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380 | case FAT_DENTRY_SKIP: |
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381 | continue; |
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382 | case FAT_DENTRY_LAST: |
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383 | block_put(b); |
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384 | return false; |
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385 | default: |
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386 | case FAT_DENTRY_VALID: |
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387 | block_put(b); |
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388 | return true; |
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389 | } |
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390 | block_put(b); |
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391 | return true; |
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392 | } |
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393 | block_put(b); |
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394 | } |
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395 | |||
396 | return false; |
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397 | } |
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398 | |||
2844 | jermar | 399 | static void *fat_root_get(dev_handle_t dev_handle) |
400 | { |
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2863 | jermar | 401 | return fat_node_get(dev_handle, 0); |
2844 | jermar | 402 | } |
403 | |||
404 | static char fat_plb_get_char(unsigned pos) |
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405 | { |
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406 | return fat_reg.plb_ro[pos % PLB_SIZE]; |
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407 | } |
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408 | |||
2831 | jermar | 409 | static bool fat_is_directory(void *node) |
410 | { |
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411 | return ((fat_node_t *)node)->type == FAT_DIRECTORY; |
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412 | } |
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413 | |||
414 | static bool fat_is_file(void *node) |
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415 | { |
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416 | return ((fat_node_t *)node)->type == FAT_FILE; |
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417 | } |
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418 | |||
2793 | jermar | 419 | /** libfs operations */ |
420 | libfs_ops_t fat_libfs_ops = { |
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421 | .match = fat_match, |
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422 | .node_get = fat_node_get, |
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2852 | jermar | 423 | .node_put = fat_node_put, |
2857 | jermar | 424 | .create = fat_create, |
425 | .destroy = fat_destroy, |
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426 | .link = fat_link, |
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427 | .unlink = fat_unlink, |
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2831 | jermar | 428 | .index_get = fat_index_get, |
429 | .size_get = fat_size_get, |
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430 | .lnkcnt_get = fat_lnkcnt_get, |
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2845 | jermar | 431 | .has_children = fat_has_children, |
2844 | jermar | 432 | .root_get = fat_root_get, |
433 | .plb_get_char = fat_plb_get_char, |
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2831 | jermar | 434 | .is_directory = fat_is_directory, |
435 | .is_file = fat_is_file |
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2793 | jermar | 436 | }; |
437 | |||
2627 | jermar | 438 | void fat_lookup(ipc_callid_t rid, ipc_call_t *request) |
439 | { |
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2793 | jermar | 440 | libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request); |
2627 | jermar | 441 | } |
442 | |||
443 | /** |
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444 | * @} |
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445 | */ |