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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 | |||
2831 | jermar | 56 | /** Hash table of FAT in-core nodes. */ |
57 | hash_table_t fin_hash; |
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58 | |||
59 | /** List of free FAT in-core nodes. */ |
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60 | link_t ffn_head; |
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61 | |||
2638 | jermar | 62 | #define FAT_NAME_LEN 8 |
63 | #define FAT_EXT_LEN 3 |
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64 | |||
65 | #define FAT_PAD ' ' |
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66 | |||
67 | #define FAT_DENTRY_UNUSED 0x00 |
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68 | #define FAT_DENTRY_E5_ESC 0x05 |
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69 | #define FAT_DENTRY_DOT 0x2e |
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70 | #define FAT_DENTRY_ERASED 0xe5 |
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71 | |||
2793 | jermar | 72 | static void dentry_name_canonify(fat_dentry_t *d, char *buf) |
2638 | jermar | 73 | { |
2793 | jermar | 74 | int i; |
2639 | jermar | 75 | |
2793 | jermar | 76 | for (i = 0; i < FAT_NAME_LEN; i++) { |
77 | if (d->name[i] == FAT_PAD) { |
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78 | buf++; |
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79 | break; |
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2639 | jermar | 80 | } |
2793 | jermar | 81 | if (d->name[i] == FAT_DENTRY_E5_ESC) |
82 | *buf++ = 0xe5; |
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83 | else |
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84 | *buf++ = d->name[i]; |
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85 | } |
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86 | if (d->ext[0] != FAT_PAD) |
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87 | *buf++ = '.'; |
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88 | for (i = 0; i < FAT_EXT_LEN; i++) { |
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89 | if (d->ext[i] == FAT_PAD) { |
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90 | *buf = '\0'; |
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91 | return; |
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92 | } |
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93 | if (d->ext[i] == FAT_DENTRY_E5_ESC) |
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94 | *buf++ = 0xe5; |
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95 | else |
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96 | *buf++ = d->ext[i]; |
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97 | } |
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98 | } |
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99 | |||
2822 | jermar | 100 | /* TODO and also move somewhere else */ |
101 | typedef struct { |
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102 | void *data; |
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103 | } block_t; |
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104 | |||
105 | static block_t *block_get(dev_handle_t dev_handle, off_t offset) |
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2793 | jermar | 106 | { |
107 | return NULL; /* TODO */ |
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108 | } |
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109 | |||
2822 | jermar | 110 | static void block_put(block_t *block) |
2793 | jermar | 111 | { |
112 | /* TODO */ |
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113 | } |
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114 | |||
2859 | jermar | 115 | #define FAT_BS(b) ((fat_bs_t *)((b)->data)) |
116 | |||
2864 | jermar | 117 | #define FAT_CLST_RES0 0x0000 |
118 | #define FAT_CLST_RES1 0x0001 /* internally used to mark root directory */ |
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2859 | jermar | 119 | #define FAT_CLST_FIRST 0x0002 |
120 | #define FAT_CLST_BAD 0xfff7 |
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121 | #define FAT_CLST_LAST1 0xfff8 |
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122 | #define FAT_CLST_LAST8 0xffff |
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123 | |||
2891 | jermar | 124 | #define fat_block_get(np, off) \ |
125 | _fat_block_get((np)->idx->dev_handle, (np)->firstc, (off)) |
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126 | |||
127 | static block_t * |
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128 | _fat_block_get(dev_handle_t dev_handle, fat_cluster_t fc, off_t offset) |
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2859 | jermar | 129 | { |
130 | block_t *bb; |
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131 | block_t *b; |
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132 | unsigned bps; |
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133 | unsigned spc; |
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134 | unsigned rscnt; /* block address of the first FAT */ |
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135 | unsigned fatcnt; |
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136 | unsigned rde; |
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137 | unsigned rds; /* root directory size */ |
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138 | unsigned sf; |
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139 | unsigned ssa; /* size of the system area */ |
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140 | unsigned clusters; |
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2891 | jermar | 141 | fat_cluster_t clst = fc; |
2859 | jermar | 142 | unsigned i; |
143 | |||
2891 | jermar | 144 | bb = block_get(dev_handle, BS_BLOCK); |
2859 | jermar | 145 | bps = uint16_t_le2host(FAT_BS(bb)->bps); |
146 | spc = FAT_BS(bb)->spc; |
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147 | rscnt = uint16_t_le2host(FAT_BS(bb)->rscnt); |
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148 | fatcnt = FAT_BS(bb)->fatcnt; |
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149 | rde = uint16_t_le2host(FAT_BS(bb)->root_ent_max); |
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150 | sf = uint16_t_le2host(FAT_BS(bb)->sec_per_fat); |
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151 | block_put(bb); |
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152 | |||
153 | rds = (sizeof(fat_dentry_t) * rde) / bps; |
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154 | rds += ((sizeof(fat_dentry_t) * rde) % bps != 0); |
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155 | ssa = rscnt + fatcnt * sf + rds; |
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156 | |||
2891 | jermar | 157 | if (fc == FAT_CLST_RES1) { |
2859 | jermar | 158 | /* root directory special case */ |
159 | assert(offset < rds); |
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2891 | jermar | 160 | b = block_get(dev_handle, rscnt + fatcnt * sf + offset); |
2859 | jermar | 161 | return b; |
162 | } |
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163 | |||
164 | clusters = offset / spc; |
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165 | for (i = 0; i < clusters; i++) { |
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166 | unsigned fsec; /* sector offset relative to FAT1 */ |
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167 | unsigned fidx; /* FAT1 entry index */ |
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168 | |||
169 | assert(clst >= FAT_CLST_FIRST && clst < FAT_CLST_BAD); |
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2864 | jermar | 170 | fsec = (clst * sizeof(fat_cluster_t)) / bps; |
171 | fidx = clst % (bps / sizeof(fat_cluster_t)); |
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2859 | jermar | 172 | /* read FAT1 */ |
2891 | jermar | 173 | b = block_get(dev_handle, rscnt + fsec); |
2864 | jermar | 174 | clst = uint16_t_le2host(((fat_cluster_t *)b->data)[fidx]); |
2859 | jermar | 175 | assert(clst != FAT_CLST_BAD); |
176 | assert(clst < FAT_CLST_LAST1); |
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177 | block_put(b); |
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178 | } |
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179 | |||
2891 | jermar | 180 | b = block_get(dev_handle, ssa + (clst - FAT_CLST_FIRST) * spc + |
181 | offset % spc); |
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2859 | jermar | 182 | |
183 | return b; |
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184 | } |
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185 | |||
2831 | jermar | 186 | static void fat_node_initialize(fat_node_t *node) |
2793 | jermar | 187 | { |
2864 | jermar | 188 | node->idx = NULL; |
2831 | jermar | 189 | node->type = 0; |
190 | link_initialize(&node->fin_link); |
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191 | link_initialize(&node->ffn_link); |
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192 | node->size = 0; |
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193 | node->lnkcnt = 0; |
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194 | node->refcnt = 0; |
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195 | node->dirty = false; |
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2793 | jermar | 196 | } |
197 | |||
2843 | jermar | 198 | static uint16_t fat_bps_get(dev_handle_t dev_handle) |
199 | { |
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200 | block_t *bb; |
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201 | uint16_t bps; |
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202 | |||
203 | bb = block_get(dev_handle, BS_BLOCK); |
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204 | assert(bb != NULL); |
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2859 | jermar | 205 | bps = uint16_t_le2host(FAT_BS(bb)->bps); |
2843 | jermar | 206 | block_put(bb); |
207 | |||
208 | return bps; |
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209 | } |
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210 | |||
2845 | jermar | 211 | typedef enum { |
212 | FAT_DENTRY_SKIP, |
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213 | FAT_DENTRY_LAST, |
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214 | FAT_DENTRY_VALID |
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215 | } fat_dentry_clsf_t; |
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216 | |||
217 | static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d) |
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218 | { |
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219 | if (d->attr & FAT_ATTR_VOLLABEL) { |
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220 | /* volume label entry */ |
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221 | return FAT_DENTRY_SKIP; |
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222 | } |
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223 | if (d->name[0] == FAT_DENTRY_ERASED) { |
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224 | /* not-currently-used entry */ |
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225 | return FAT_DENTRY_SKIP; |
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226 | } |
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227 | if (d->name[0] == FAT_DENTRY_UNUSED) { |
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228 | /* never used entry */ |
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229 | return FAT_DENTRY_LAST; |
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230 | } |
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231 | if (d->name[0] == FAT_DENTRY_DOT) { |
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232 | /* |
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233 | * Most likely '.' or '..'. |
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234 | * It cannot occur in a regular file name. |
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235 | */ |
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236 | return FAT_DENTRY_SKIP; |
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237 | } |
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238 | return FAT_DENTRY_VALID; |
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239 | } |
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240 | |||
2831 | jermar | 241 | static void fat_sync_node(fat_node_t *node) |
242 | { |
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243 | /* TODO */ |
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244 | } |
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245 | |||
2863 | jermar | 246 | /** Instantiate a FAT in-core node. */ |
2891 | jermar | 247 | static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index) |
2831 | jermar | 248 | { |
2891 | jermar | 249 | fat_idx_t *idx; |
250 | block_t *b; |
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251 | fat_dentry_t *d; |
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252 | fat_node_t *nodep; |
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253 | unsigned bps; |
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254 | unsigned dps; |
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255 | |||
256 | idx = fat_idx_get_by_index(dev_handle, index); |
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257 | if (!idx) |
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258 | return NULL; |
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259 | |||
260 | if (idx->nodep) { |
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261 | /* |
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262 | * We are lucky. |
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263 | * The node is already instantiated in memory. |
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264 | */ |
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265 | idx->nodep->refcnt++; |
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266 | return idx->nodep; |
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267 | } |
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268 | |||
269 | /* |
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270 | * We must instantiate the node from the file system. |
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271 | */ |
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272 | |||
273 | assert(idx->pfc); |
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274 | |||
275 | nodep = (fat_node_t *)malloc(sizeof(fat_node_t)); |
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276 | if (!nodep) |
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277 | return NULL; |
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278 | fat_node_initialize(nodep); |
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279 | |||
280 | bps = fat_bps_get(dev_handle); |
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281 | dps = bps / sizeof(fat_dentry_t); |
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282 | |||
283 | b = _fat_block_get(dev_handle, idx->pfc, |
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284 | (idx->pdi * sizeof(fat_dentry_t)) / bps); |
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285 | |||
286 | assert(b); |
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287 | |||
288 | d = ((fat_dentry_t *)b->data) + (idx->pdi % dps); |
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289 | /* XXX */ |
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2831 | jermar | 290 | } |
291 | |||
2852 | jermar | 292 | static void fat_node_put(void *node) |
293 | { |
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2863 | jermar | 294 | /* TODO */ |
2852 | jermar | 295 | } |
296 | |||
2857 | jermar | 297 | static void *fat_create(int flags) |
298 | { |
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299 | return NULL; /* not supported at the moment */ |
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300 | } |
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301 | |||
2858 | jermar | 302 | static int fat_destroy(void *node) |
2857 | jermar | 303 | { |
2858 | jermar | 304 | return ENOTSUP; /* not supported at the moment */ |
2857 | jermar | 305 | } |
306 | |||
307 | static bool fat_link(void *prnt, void *chld, const char *name) |
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308 | { |
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309 | return false; /* not supported at the moment */ |
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310 | } |
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311 | |||
312 | static int fat_unlink(void *prnt, void *chld) |
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313 | { |
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314 | return ENOTSUP; /* not supported at the moment */ |
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315 | } |
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316 | |||
2793 | jermar | 317 | static void *fat_match(void *prnt, const char *component) |
318 | { |
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319 | fat_node_t *parentp = (fat_node_t *)prnt; |
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320 | char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1]; |
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2822 | jermar | 321 | unsigned i, j; |
2828 | jermar | 322 | unsigned bps; /* bytes per sector */ |
2822 | jermar | 323 | unsigned dps; /* dentries per sector */ |
324 | unsigned blocks; |
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2793 | jermar | 325 | fat_dentry_t *d; |
2822 | jermar | 326 | block_t *b; |
2793 | jermar | 327 | |
2864 | jermar | 328 | bps = fat_bps_get(parentp->idx->dev_handle); |
2828 | jermar | 329 | dps = bps / sizeof(fat_dentry_t); |
330 | blocks = parentp->size / bps + (parentp->size % bps != 0); |
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2822 | jermar | 331 | for (i = 0; i < blocks; i++) { |
332 | unsigned dentries; |
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2793 | jermar | 333 | |
2864 | jermar | 334 | b = fat_block_get(parentp, i); |
2822 | jermar | 335 | dentries = (i == blocks - 1) ? |
336 | parentp->size % sizeof(fat_dentry_t) : |
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337 | dps; |
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338 | for (j = 0; j < dentries; j++) { |
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339 | d = ((fat_dentry_t *)b->data) + j; |
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2845 | jermar | 340 | switch (fat_classify_dentry(d)) { |
341 | case FAT_DENTRY_SKIP: |
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2822 | jermar | 342 | continue; |
2845 | jermar | 343 | case FAT_DENTRY_LAST: |
2822 | jermar | 344 | block_put(b); |
345 | return NULL; |
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2845 | jermar | 346 | default: |
347 | case FAT_DENTRY_VALID: |
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348 | dentry_name_canonify(d, name); |
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349 | break; |
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2822 | jermar | 350 | } |
351 | if (strcmp(name, component) == 0) { |
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352 | /* hit */ |
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2890 | jermar | 353 | fat_idx_t *idx = fat_idx_get_by_pos( |
2881 | jermar | 354 | parentp->idx->dev_handle, parentp->firstc, |
2864 | jermar | 355 | i * dps + j); |
2890 | jermar | 356 | if (!idx) { |
357 | /* |
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358 | * Can happen if memory is low or if we |
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359 | * run out of 32-bit indices. |
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360 | */ |
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361 | block_put(b); |
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362 | return NULL; |
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363 | } |
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2864 | jermar | 364 | void *node = fat_node_get(idx->dev_handle, |
365 | idx->index); |
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2822 | jermar | 366 | block_put(b); |
367 | return node; |
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368 | } |
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2793 | jermar | 369 | } |
2822 | jermar | 370 | block_put(b); |
2639 | jermar | 371 | } |
2793 | jermar | 372 | |
373 | return NULL; |
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2638 | jermar | 374 | } |
375 | |||
2831 | jermar | 376 | static fs_index_t fat_index_get(void *node) |
377 | { |
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378 | fat_node_t *fnodep = (fat_node_t *)node; |
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379 | if (!fnodep) |
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380 | return 0; |
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2864 | jermar | 381 | return fnodep->idx->index; |
2831 | jermar | 382 | } |
383 | |||
384 | static size_t fat_size_get(void *node) |
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385 | { |
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386 | return ((fat_node_t *)node)->size; |
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387 | } |
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388 | |||
389 | static unsigned fat_lnkcnt_get(void *node) |
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390 | { |
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391 | return ((fat_node_t *)node)->lnkcnt; |
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392 | } |
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393 | |||
2845 | jermar | 394 | static bool fat_has_children(void *node) |
395 | { |
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396 | fat_node_t *nodep = (fat_node_t *)node; |
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397 | unsigned bps; |
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398 | unsigned dps; |
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399 | unsigned blocks; |
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400 | block_t *b; |
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401 | unsigned i, j; |
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402 | |||
403 | if (nodep->type != FAT_DIRECTORY) |
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404 | return false; |
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405 | |||
2864 | jermar | 406 | bps = fat_bps_get(nodep->idx->dev_handle); |
2845 | jermar | 407 | dps = bps / sizeof(fat_dentry_t); |
408 | |||
409 | blocks = nodep->size / bps + (nodep->size % bps != 0); |
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410 | |||
411 | for (i = 0; i < blocks; i++) { |
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412 | unsigned dentries; |
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413 | fat_dentry_t *d; |
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414 | |||
2864 | jermar | 415 | b = fat_block_get(nodep, i); |
2845 | jermar | 416 | dentries = (i == blocks - 1) ? |
417 | nodep->size % sizeof(fat_dentry_t) : |
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418 | dps; |
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419 | for (j = 0; j < dentries; j++) { |
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420 | d = ((fat_dentry_t *)b->data) + j; |
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421 | switch (fat_classify_dentry(d)) { |
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422 | case FAT_DENTRY_SKIP: |
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423 | continue; |
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424 | case FAT_DENTRY_LAST: |
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425 | block_put(b); |
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426 | return false; |
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427 | default: |
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428 | case FAT_DENTRY_VALID: |
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429 | block_put(b); |
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430 | return true; |
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431 | } |
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432 | block_put(b); |
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433 | return true; |
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434 | } |
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435 | block_put(b); |
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436 | } |
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437 | |||
438 | return false; |
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439 | } |
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440 | |||
2844 | jermar | 441 | static void *fat_root_get(dev_handle_t dev_handle) |
442 | { |
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2891 | jermar | 443 | return fat_node_get(dev_handle, 0); /* TODO */ |
2844 | jermar | 444 | } |
445 | |||
446 | static char fat_plb_get_char(unsigned pos) |
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447 | { |
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448 | return fat_reg.plb_ro[pos % PLB_SIZE]; |
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449 | } |
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450 | |||
2831 | jermar | 451 | static bool fat_is_directory(void *node) |
452 | { |
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453 | return ((fat_node_t *)node)->type == FAT_DIRECTORY; |
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454 | } |
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455 | |||
456 | static bool fat_is_file(void *node) |
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457 | { |
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458 | return ((fat_node_t *)node)->type == FAT_FILE; |
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459 | } |
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460 | |||
2793 | jermar | 461 | /** libfs operations */ |
462 | libfs_ops_t fat_libfs_ops = { |
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463 | .match = fat_match, |
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464 | .node_get = fat_node_get, |
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2852 | jermar | 465 | .node_put = fat_node_put, |
2857 | jermar | 466 | .create = fat_create, |
467 | .destroy = fat_destroy, |
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468 | .link = fat_link, |
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469 | .unlink = fat_unlink, |
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2831 | jermar | 470 | .index_get = fat_index_get, |
471 | .size_get = fat_size_get, |
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472 | .lnkcnt_get = fat_lnkcnt_get, |
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2845 | jermar | 473 | .has_children = fat_has_children, |
2844 | jermar | 474 | .root_get = fat_root_get, |
475 | .plb_get_char = fat_plb_get_char, |
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2831 | jermar | 476 | .is_directory = fat_is_directory, |
477 | .is_file = fat_is_file |
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2793 | jermar | 478 | }; |
479 | |||
2627 | jermar | 480 | void fat_lookup(ipc_callid_t rid, ipc_call_t *request) |
481 | { |
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2793 | jermar | 482 | libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request); |
2627 | jermar | 483 | } |
484 | |||
485 | /** |
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486 | * @} |
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487 | */ |