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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 | |||
2831 | jermar | 113 | static block_t *fat_block_get(dev_handle_t dev_handle, fs_index_t index, |
114 | off_t offset) { |
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2822 | jermar | 115 | return NULL; /* TODO */ |
116 | } |
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117 | |||
118 | static void block_put(block_t *block) |
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2793 | jermar | 119 | { |
120 | /* TODO */ |
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121 | } |
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122 | |||
2831 | jermar | 123 | static void fat_node_initialize(fat_node_t *node) |
2793 | jermar | 124 | { |
2856 | jermar | 125 | futex_initialize(&node->lock, 1); |
2831 | jermar | 126 | node->type = 0; |
127 | node->index = 0; |
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128 | node->pindex = 0; |
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129 | node->dev_handle = 0; |
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130 | link_initialize(&node->fin_link); |
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131 | link_initialize(&node->ffn_link); |
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132 | node->size = 0; |
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133 | node->lnkcnt = 0; |
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134 | node->refcnt = 0; |
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135 | node->dirty = false; |
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2793 | jermar | 136 | } |
137 | |||
2843 | jermar | 138 | static uint16_t fat_bps_get(dev_handle_t dev_handle) |
139 | { |
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140 | block_t *bb; |
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141 | uint16_t bps; |
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142 | |||
143 | bb = block_get(dev_handle, BS_BLOCK); |
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144 | assert(bb != NULL); |
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145 | bps = uint16_t_le2host(((fat_bs_t *)bb->data)->bps); |
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146 | block_put(bb); |
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147 | |||
148 | return bps; |
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149 | } |
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150 | |||
2845 | jermar | 151 | typedef enum { |
152 | FAT_DENTRY_SKIP, |
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153 | FAT_DENTRY_LAST, |
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154 | FAT_DENTRY_VALID |
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155 | } fat_dentry_clsf_t; |
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156 | |||
157 | static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d) |
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158 | { |
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159 | if (d->attr & FAT_ATTR_VOLLABEL) { |
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160 | /* volume label entry */ |
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161 | return FAT_DENTRY_SKIP; |
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162 | } |
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163 | if (d->name[0] == FAT_DENTRY_ERASED) { |
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164 | /* not-currently-used entry */ |
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165 | return FAT_DENTRY_SKIP; |
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166 | } |
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167 | if (d->name[0] == FAT_DENTRY_UNUSED) { |
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168 | /* never used entry */ |
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169 | return FAT_DENTRY_LAST; |
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170 | } |
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171 | if (d->name[0] == FAT_DENTRY_DOT) { |
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172 | /* |
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173 | * Most likely '.' or '..'. |
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174 | * It cannot occur in a regular file name. |
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175 | */ |
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176 | return FAT_DENTRY_SKIP; |
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177 | } |
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178 | return FAT_DENTRY_VALID; |
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179 | } |
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180 | |||
2831 | jermar | 181 | static void fat_sync_node(fat_node_t *node) |
182 | { |
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183 | /* TODO */ |
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184 | } |
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185 | |||
2843 | jermar | 186 | /** Instantiate a FAT in-core node. |
187 | * |
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188 | * FAT stores the info necessary for instantiation of a node in the parent of |
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189 | * that node. This design necessitated the addition of the parent node index |
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190 | * parameter to this otherwise generic libfs API. |
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191 | */ |
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2831 | jermar | 192 | static void * |
193 | fat_node_get(dev_handle_t dev_handle, fs_index_t index, fs_index_t pindex) |
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194 | { |
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195 | link_t *lnk; |
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196 | fat_node_t *node = NULL; |
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197 | block_t *b; |
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2843 | jermar | 198 | unsigned bps; |
199 | unsigned dps; |
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2831 | jermar | 200 | fat_dentry_t *d; |
2843 | jermar | 201 | unsigned i, j; |
2831 | jermar | 202 | |
203 | unsigned long key[] = { |
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2843 | jermar | 204 | [FIN_KEY_DEV_HANDLE] = dev_handle, |
205 | [FIN_KEY_INDEX] = index |
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2831 | jermar | 206 | }; |
207 | |||
2856 | jermar | 208 | futex_down(&fin_futex); |
2831 | jermar | 209 | lnk = hash_table_find(&fin_hash, key); |
210 | if (lnk) { |
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211 | /* |
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212 | * The in-core node was found in the hash table. |
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213 | */ |
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214 | node = hash_table_get_instance(lnk, fat_node_t, fin_link); |
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215 | if (!node->refcnt++) |
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216 | list_remove(&node->ffn_link); |
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2856 | jermar | 217 | futex_up(&fin_futex); |
218 | |||
219 | /* Make sure that the node is fully instantiated. */ |
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220 | futex_down(&node->lock); |
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221 | futex_up(&node->lock); |
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222 | |||
2831 | jermar | 223 | return (void *) node; |
224 | } |
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225 | |||
2843 | jermar | 226 | bps = fat_bps_get(dev_handle); |
227 | dps = bps / sizeof(fat_dentry_t); |
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228 | |||
2831 | jermar | 229 | if (!list_empty(&ffn_head)) { |
230 | /* |
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231 | * We are going to reuse a node from the free list. |
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232 | */ |
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233 | lnk = ffn_head.next; |
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234 | list_remove(lnk); |
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235 | node = list_get_instance(lnk, fat_node_t, ffn_link); |
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236 | assert(!node->refcnt); |
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237 | if (node->dirty) |
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238 | fat_sync_node(node); |
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2843 | jermar | 239 | key[FIN_KEY_DEV_HANDLE] = node->dev_handle; |
240 | key[FIN_KEY_INDEX] = node->index; |
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241 | hash_table_remove(&fin_hash, key, sizeof(key)/sizeof(*key)); |
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2831 | jermar | 242 | } else { |
243 | /* |
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244 | * We need to allocate a new node. |
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245 | */ |
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246 | node = malloc(sizeof(fat_node_t)); |
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247 | if (!node) |
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248 | return NULL; |
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249 | } |
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250 | fat_node_initialize(node); |
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2843 | jermar | 251 | node->refcnt++; |
252 | node->lnkcnt++; |
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253 | node->dev_handle = dev_handle; |
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254 | node->index = index; |
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255 | node->pindex = pindex; |
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2856 | jermar | 256 | key[FIN_KEY_DEV_HANDLE] = node->dev_handle; |
257 | key[FIN_KEY_INDEX] = node->index; |
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258 | hash_table_insert(&fin_hash, key, &node->fin_link); |
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2831 | jermar | 259 | |
2843 | jermar | 260 | /* |
2856 | jermar | 261 | * We have already put the node back to fin_hash. |
262 | * The node is not yet fully instantiated so we lock it prior to |
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263 | * unlocking fin_hash. |
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264 | */ |
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265 | futex_down(&node->lock); |
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266 | futex_up(&fin_futex); |
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267 | |||
268 | /* |
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2843 | jermar | 269 | * Because of the design of the FAT file system, we have no clue about |
270 | * how big (i.e. how many directory entries it contains) is the parent |
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271 | * of the node we are trying to instantiate. However, we know that it |
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272 | * must contain a directory entry for our node of interest. We simply |
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273 | * scan the parent until we find it. |
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274 | */ |
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275 | for (i = 0; ; i++) { |
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276 | b = fat_block_get(node->dev_handle, node->pindex, i); |
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277 | for (j = 0; j < dps; j++) { |
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278 | d = ((fat_dentry_t *)b->data) + j; |
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279 | if (d->firstc == node->index) |
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280 | goto found; |
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281 | } |
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282 | block_put(b); |
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2831 | jermar | 283 | } |
2843 | jermar | 284 | |
285 | found: |
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286 | if (!(d->attr & (FAT_ATTR_SUBDIR | FAT_ATTR_VOLLABEL))) |
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287 | node->type = FAT_FILE; |
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2844 | jermar | 288 | if ((d->attr & FAT_ATTR_SUBDIR) || !index) |
2843 | jermar | 289 | node->type = FAT_DIRECTORY; |
290 | assert((node->type == FAT_FILE) || (node->type == FAT_DIRECTORY)); |
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291 | |||
292 | node->size = uint32_t_le2host(d->size); |
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293 | block_put(b); |
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2831 | jermar | 294 | |
2856 | jermar | 295 | futex_up(&node->lock); |
2843 | jermar | 296 | return node; |
2831 | jermar | 297 | } |
298 | |||
2852 | jermar | 299 | static void fat_node_put(void *node) |
300 | { |
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2855 | jermar | 301 | fat_node_t *nodep = (fat_node_t *)node; |
302 | |||
2856 | jermar | 303 | futex_down(&fin_futex); |
304 | if (!--nodep->refcnt) |
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2855 | jermar | 305 | list_append(&nodep->ffn_link, &ffn_head); |
2856 | jermar | 306 | futex_up(&fin_futex); |
2852 | jermar | 307 | } |
308 | |||
2857 | jermar | 309 | static void *fat_create(int flags) |
310 | { |
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311 | return NULL; /* not supported at the moment */ |
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312 | } |
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313 | |||
314 | static bool fat_destroy(void *node) |
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315 | { |
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316 | return false; /* not supported at the moment */ |
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317 | } |
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318 | |||
319 | static bool fat_link(void *prnt, void *chld, const char *name) |
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320 | { |
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321 | return false; /* not supported at the moment */ |
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322 | } |
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323 | |||
324 | static int fat_unlink(void *prnt, void *chld) |
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325 | { |
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326 | return ENOTSUP; /* not supported at the moment */ |
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327 | } |
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328 | |||
2793 | jermar | 329 | static void *fat_match(void *prnt, const char *component) |
330 | { |
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331 | fat_node_t *parentp = (fat_node_t *)prnt; |
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332 | char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1]; |
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2822 | jermar | 333 | unsigned i, j; |
2828 | jermar | 334 | unsigned bps; /* bytes per sector */ |
2822 | jermar | 335 | unsigned dps; /* dentries per sector */ |
336 | unsigned blocks; |
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2793 | jermar | 337 | fat_dentry_t *d; |
2822 | jermar | 338 | block_t *b; |
2793 | jermar | 339 | |
2843 | jermar | 340 | bps = fat_bps_get(parentp->dev_handle); |
2828 | jermar | 341 | dps = bps / sizeof(fat_dentry_t); |
342 | blocks = parentp->size / bps + (parentp->size % bps != 0); |
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2822 | jermar | 343 | for (i = 0; i < blocks; i++) { |
344 | unsigned dentries; |
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2793 | jermar | 345 | |
2831 | jermar | 346 | b = fat_block_get(parentp->dev_handle, parentp->index, i); |
2822 | jermar | 347 | dentries = (i == blocks - 1) ? |
348 | parentp->size % sizeof(fat_dentry_t) : |
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349 | dps; |
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350 | for (j = 0; j < dentries; j++) { |
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351 | d = ((fat_dentry_t *)b->data) + j; |
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2845 | jermar | 352 | switch (fat_classify_dentry(d)) { |
353 | case FAT_DENTRY_SKIP: |
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2822 | jermar | 354 | continue; |
2845 | jermar | 355 | case FAT_DENTRY_LAST: |
2822 | jermar | 356 | block_put(b); |
357 | return NULL; |
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2845 | jermar | 358 | default: |
359 | case FAT_DENTRY_VALID: |
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360 | dentry_name_canonify(d, name); |
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361 | break; |
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2822 | jermar | 362 | } |
363 | if (strcmp(name, component) == 0) { |
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364 | /* hit */ |
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365 | void *node = fat_node_get(parentp->dev_handle, |
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2831 | jermar | 366 | (fs_index_t)uint16_t_le2host(d->firstc), |
367 | parentp->index); |
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2822 | jermar | 368 | block_put(b); |
369 | return node; |
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370 | } |
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2793 | jermar | 371 | } |
2822 | jermar | 372 | block_put(b); |
2639 | jermar | 373 | } |
2793 | jermar | 374 | |
375 | return NULL; |
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2638 | jermar | 376 | } |
377 | |||
2831 | jermar | 378 | static fs_index_t fat_index_get(void *node) |
379 | { |
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380 | fat_node_t *fnodep = (fat_node_t *)node; |
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381 | if (!fnodep) |
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382 | return 0; |
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383 | return fnodep->index; |
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384 | } |
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385 | |||
386 | static size_t fat_size_get(void *node) |
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387 | { |
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388 | return ((fat_node_t *)node)->size; |
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389 | } |
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390 | |||
391 | static unsigned fat_lnkcnt_get(void *node) |
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392 | { |
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393 | return ((fat_node_t *)node)->lnkcnt; |
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394 | } |
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395 | |||
2845 | jermar | 396 | static bool fat_has_children(void *node) |
397 | { |
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398 | fat_node_t *nodep = (fat_node_t *)node; |
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399 | unsigned bps; |
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400 | unsigned dps; |
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401 | unsigned blocks; |
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402 | block_t *b; |
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403 | unsigned i, j; |
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404 | |||
405 | if (nodep->type != FAT_DIRECTORY) |
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406 | return false; |
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407 | |||
408 | bps = fat_bps_get(nodep->dev_handle); |
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409 | dps = bps / sizeof(fat_dentry_t); |
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410 | |||
411 | blocks = nodep->size / bps + (nodep->size % bps != 0); |
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412 | |||
413 | for (i = 0; i < blocks; i++) { |
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414 | unsigned dentries; |
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415 | fat_dentry_t *d; |
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416 | |||
417 | b = fat_block_get(nodep->dev_handle, nodep->index, i); |
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418 | dentries = (i == blocks - 1) ? |
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419 | nodep->size % sizeof(fat_dentry_t) : |
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420 | dps; |
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421 | for (j = 0; j < dentries; j++) { |
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422 | d = ((fat_dentry_t *)b->data) + j; |
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423 | switch (fat_classify_dentry(d)) { |
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424 | case FAT_DENTRY_SKIP: |
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425 | continue; |
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426 | case FAT_DENTRY_LAST: |
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427 | block_put(b); |
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428 | return false; |
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429 | default: |
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430 | case FAT_DENTRY_VALID: |
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431 | block_put(b); |
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432 | return true; |
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433 | } |
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434 | block_put(b); |
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435 | return true; |
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436 | } |
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437 | block_put(b); |
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438 | } |
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439 | |||
440 | return false; |
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441 | } |
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442 | |||
2844 | jermar | 443 | static void *fat_root_get(dev_handle_t dev_handle) |
444 | { |
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445 | return fat_node_get(dev_handle, 0, 0); |
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446 | } |
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447 | |||
448 | static char fat_plb_get_char(unsigned pos) |
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449 | { |
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450 | return fat_reg.plb_ro[pos % PLB_SIZE]; |
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451 | } |
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452 | |||
2831 | jermar | 453 | static bool fat_is_directory(void *node) |
454 | { |
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455 | return ((fat_node_t *)node)->type == FAT_DIRECTORY; |
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456 | } |
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457 | |||
458 | static bool fat_is_file(void *node) |
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459 | { |
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460 | return ((fat_node_t *)node)->type == FAT_FILE; |
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461 | } |
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462 | |||
2793 | jermar | 463 | /** libfs operations */ |
464 | libfs_ops_t fat_libfs_ops = { |
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465 | .match = fat_match, |
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466 | .node_get = fat_node_get, |
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2852 | jermar | 467 | .node_put = fat_node_put, |
2857 | jermar | 468 | .create = fat_create, |
469 | .destroy = fat_destroy, |
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470 | .link = fat_link, |
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471 | .unlink = fat_unlink, |
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2831 | jermar | 472 | .index_get = fat_index_get, |
473 | .size_get = fat_size_get, |
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474 | .lnkcnt_get = fat_lnkcnt_get, |
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2845 | jermar | 475 | .has_children = fat_has_children, |
2844 | jermar | 476 | .root_get = fat_root_get, |
477 | .plb_get_char = fat_plb_get_char, |
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2831 | jermar | 478 | .is_directory = fat_is_directory, |
479 | .is_file = fat_is_file |
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2793 | jermar | 480 | }; |
481 | |||
2627 | jermar | 482 | void fat_lookup(ipc_callid_t rid, ipc_call_t *request) |
483 | { |
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2793 | jermar | 484 | libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request); |
2627 | jermar | 485 | } |
486 | |||
487 | /** |
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488 | * @} |
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489 | */ |