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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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2627 | jermar | 49 | |
2843 | jermar | 50 | #define BS_BLOCK 0 |
51 | |||
52 | #define FIN_KEY_DEV_HANDLE 0 |
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53 | #define FIN_KEY_INDEX 1 |
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54 | |||
2831 | jermar | 55 | /** Hash table of FAT in-core nodes. */ |
56 | hash_table_t fin_hash; |
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57 | |||
58 | /** List of free FAT in-core nodes. */ |
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59 | link_t ffn_head; |
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60 | |||
2638 | jermar | 61 | #define FAT_NAME_LEN 8 |
62 | #define FAT_EXT_LEN 3 |
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63 | |||
64 | #define FAT_PAD ' ' |
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65 | |||
66 | #define FAT_DENTRY_UNUSED 0x00 |
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67 | #define FAT_DENTRY_E5_ESC 0x05 |
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68 | #define FAT_DENTRY_DOT 0x2e |
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69 | #define FAT_DENTRY_ERASED 0xe5 |
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70 | |||
2793 | jermar | 71 | static void dentry_name_canonify(fat_dentry_t *d, char *buf) |
2638 | jermar | 72 | { |
2793 | jermar | 73 | int i; |
2639 | jermar | 74 | |
2793 | jermar | 75 | for (i = 0; i < FAT_NAME_LEN; i++) { |
76 | if (d->name[i] == FAT_PAD) { |
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77 | buf++; |
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78 | break; |
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2639 | jermar | 79 | } |
2793 | jermar | 80 | if (d->name[i] == FAT_DENTRY_E5_ESC) |
81 | *buf++ = 0xe5; |
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82 | else |
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83 | *buf++ = d->name[i]; |
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84 | } |
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85 | if (d->ext[0] != FAT_PAD) |
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86 | *buf++ = '.'; |
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87 | for (i = 0; i < FAT_EXT_LEN; i++) { |
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88 | if (d->ext[i] == FAT_PAD) { |
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89 | *buf = '\0'; |
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90 | return; |
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91 | } |
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92 | if (d->ext[i] == FAT_DENTRY_E5_ESC) |
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93 | *buf++ = 0xe5; |
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94 | else |
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95 | *buf++ = d->ext[i]; |
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96 | } |
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97 | } |
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98 | |||
2822 | jermar | 99 | /* TODO and also move somewhere else */ |
100 | typedef struct { |
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101 | void *data; |
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102 | } block_t; |
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103 | |||
104 | static block_t *block_get(dev_handle_t dev_handle, off_t offset) |
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2793 | jermar | 105 | { |
106 | return NULL; /* TODO */ |
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107 | } |
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108 | |||
2831 | jermar | 109 | static block_t *fat_block_get(dev_handle_t dev_handle, fs_index_t index, |
110 | off_t offset) { |
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2822 | jermar | 111 | return NULL; /* TODO */ |
112 | } |
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113 | |||
114 | static void block_put(block_t *block) |
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2793 | jermar | 115 | { |
116 | /* TODO */ |
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117 | } |
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118 | |||
2831 | jermar | 119 | static void fat_node_initialize(fat_node_t *node) |
2793 | jermar | 120 | { |
2831 | jermar | 121 | node->type = 0; |
122 | node->index = 0; |
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123 | node->pindex = 0; |
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124 | node->dev_handle = 0; |
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125 | link_initialize(&node->fin_link); |
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126 | link_initialize(&node->ffn_link); |
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127 | node->size = 0; |
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128 | node->lnkcnt = 0; |
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129 | node->refcnt = 0; |
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130 | node->dirty = false; |
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2793 | jermar | 131 | } |
132 | |||
2843 | jermar | 133 | static uint16_t fat_bps_get(dev_handle_t dev_handle) |
134 | { |
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135 | block_t *bb; |
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136 | uint16_t bps; |
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137 | |||
138 | bb = block_get(dev_handle, BS_BLOCK); |
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139 | assert(bb != NULL); |
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140 | bps = uint16_t_le2host(((fat_bs_t *)bb->data)->bps); |
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141 | block_put(bb); |
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142 | |||
143 | return bps; |
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144 | } |
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145 | |||
2845 | jermar | 146 | typedef enum { |
147 | FAT_DENTRY_SKIP, |
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148 | FAT_DENTRY_LAST, |
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149 | FAT_DENTRY_VALID |
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150 | } fat_dentry_clsf_t; |
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151 | |||
152 | static fat_dentry_clsf_t fat_classify_dentry(fat_dentry_t *d) |
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153 | { |
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154 | if (d->attr & FAT_ATTR_VOLLABEL) { |
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155 | /* volume label entry */ |
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156 | return FAT_DENTRY_SKIP; |
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157 | } |
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158 | if (d->name[0] == FAT_DENTRY_ERASED) { |
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159 | /* not-currently-used entry */ |
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160 | return FAT_DENTRY_SKIP; |
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161 | } |
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162 | if (d->name[0] == FAT_DENTRY_UNUSED) { |
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163 | /* never used entry */ |
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164 | return FAT_DENTRY_LAST; |
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165 | } |
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166 | if (d->name[0] == FAT_DENTRY_DOT) { |
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167 | /* |
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168 | * Most likely '.' or '..'. |
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169 | * It cannot occur in a regular file name. |
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170 | */ |
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171 | return FAT_DENTRY_SKIP; |
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172 | } |
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173 | return FAT_DENTRY_VALID; |
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174 | } |
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175 | |||
2831 | jermar | 176 | static void fat_sync_node(fat_node_t *node) |
177 | { |
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178 | /* TODO */ |
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179 | } |
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180 | |||
2843 | jermar | 181 | /** Instantiate a FAT in-core node. |
182 | * |
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183 | * FAT stores the info necessary for instantiation of a node in the parent of |
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184 | * that node. This design necessitated the addition of the parent node index |
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185 | * parameter to this otherwise generic libfs API. |
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186 | */ |
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2831 | jermar | 187 | static void * |
188 | fat_node_get(dev_handle_t dev_handle, fs_index_t index, fs_index_t pindex) |
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189 | { |
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190 | link_t *lnk; |
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191 | fat_node_t *node = NULL; |
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192 | block_t *b; |
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2843 | jermar | 193 | unsigned bps; |
194 | unsigned dps; |
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2831 | jermar | 195 | fat_dentry_t *d; |
2843 | jermar | 196 | unsigned i, j; |
2831 | jermar | 197 | |
198 | unsigned long key[] = { |
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2843 | jermar | 199 | [FIN_KEY_DEV_HANDLE] = dev_handle, |
200 | [FIN_KEY_INDEX] = index |
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2831 | jermar | 201 | }; |
202 | |||
203 | lnk = hash_table_find(&fin_hash, key); |
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204 | if (lnk) { |
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205 | /* |
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206 | * The in-core node was found in the hash table. |
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207 | */ |
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208 | node = hash_table_get_instance(lnk, fat_node_t, fin_link); |
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209 | if (!node->refcnt++) |
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210 | list_remove(&node->ffn_link); |
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211 | return (void *) node; |
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212 | } |
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213 | |||
2843 | jermar | 214 | bps = fat_bps_get(dev_handle); |
215 | dps = bps / sizeof(fat_dentry_t); |
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216 | |||
2831 | jermar | 217 | if (!list_empty(&ffn_head)) { |
218 | /* |
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219 | * We are going to reuse a node from the free list. |
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220 | */ |
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221 | lnk = ffn_head.next; |
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222 | list_remove(lnk); |
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223 | node = list_get_instance(lnk, fat_node_t, ffn_link); |
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224 | assert(!node->refcnt); |
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225 | if (node->dirty) |
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226 | fat_sync_node(node); |
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2843 | jermar | 227 | key[FIN_KEY_DEV_HANDLE] = node->dev_handle; |
228 | key[FIN_KEY_INDEX] = node->index; |
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229 | hash_table_remove(&fin_hash, key, sizeof(key)/sizeof(*key)); |
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2831 | jermar | 230 | } else { |
231 | /* |
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232 | * We need to allocate a new node. |
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233 | */ |
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234 | node = malloc(sizeof(fat_node_t)); |
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235 | if (!node) |
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236 | return NULL; |
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237 | } |
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238 | fat_node_initialize(node); |
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2843 | jermar | 239 | node->refcnt++; |
240 | node->lnkcnt++; |
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241 | node->dev_handle = dev_handle; |
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242 | node->index = index; |
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243 | node->pindex = pindex; |
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2831 | jermar | 244 | |
2843 | jermar | 245 | /* |
246 | * Because of the design of the FAT file system, we have no clue about |
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247 | * how big (i.e. how many directory entries it contains) is the parent |
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248 | * of the node we are trying to instantiate. However, we know that it |
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249 | * must contain a directory entry for our node of interest. We simply |
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250 | * scan the parent until we find it. |
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251 | */ |
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252 | for (i = 0; ; i++) { |
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253 | b = fat_block_get(node->dev_handle, node->pindex, i); |
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254 | for (j = 0; j < dps; j++) { |
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255 | d = ((fat_dentry_t *)b->data) + j; |
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256 | if (d->firstc == node->index) |
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257 | goto found; |
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258 | } |
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259 | block_put(b); |
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2831 | jermar | 260 | } |
2843 | jermar | 261 | |
262 | found: |
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263 | if (!(d->attr & (FAT_ATTR_SUBDIR | FAT_ATTR_VOLLABEL))) |
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264 | node->type = FAT_FILE; |
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2844 | jermar | 265 | if ((d->attr & FAT_ATTR_SUBDIR) || !index) |
2843 | jermar | 266 | node->type = FAT_DIRECTORY; |
267 | assert((node->type == FAT_FILE) || (node->type == FAT_DIRECTORY)); |
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268 | |||
269 | node->size = uint32_t_le2host(d->size); |
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270 | block_put(b); |
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271 | |||
272 | key[FIN_KEY_DEV_HANDLE] = node->dev_handle; |
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273 | key[FIN_KEY_INDEX] = node->index; |
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274 | hash_table_insert(&fin_hash, key, &node->fin_link); |
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2831 | jermar | 275 | |
2843 | jermar | 276 | return node; |
2831 | jermar | 277 | } |
278 | |||
2793 | jermar | 279 | static void *fat_match(void *prnt, const char *component) |
280 | { |
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281 | fat_node_t *parentp = (fat_node_t *)prnt; |
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282 | char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1]; |
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2822 | jermar | 283 | unsigned i, j; |
2828 | jermar | 284 | unsigned bps; /* bytes per sector */ |
2822 | jermar | 285 | unsigned dps; /* dentries per sector */ |
286 | unsigned blocks; |
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2793 | jermar | 287 | fat_dentry_t *d; |
2822 | jermar | 288 | block_t *b; |
2793 | jermar | 289 | |
2843 | jermar | 290 | bps = fat_bps_get(parentp->dev_handle); |
2828 | jermar | 291 | dps = bps / sizeof(fat_dentry_t); |
292 | blocks = parentp->size / bps + (parentp->size % bps != 0); |
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2822 | jermar | 293 | for (i = 0; i < blocks; i++) { |
294 | unsigned dentries; |
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2793 | jermar | 295 | |
2831 | jermar | 296 | b = fat_block_get(parentp->dev_handle, parentp->index, i); |
2822 | jermar | 297 | dentries = (i == blocks - 1) ? |
298 | parentp->size % sizeof(fat_dentry_t) : |
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299 | dps; |
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300 | for (j = 0; j < dentries; j++) { |
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301 | d = ((fat_dentry_t *)b->data) + j; |
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2845 | jermar | 302 | switch (fat_classify_dentry(d)) { |
303 | case FAT_DENTRY_SKIP: |
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2822 | jermar | 304 | continue; |
2845 | jermar | 305 | case FAT_DENTRY_LAST: |
2822 | jermar | 306 | block_put(b); |
307 | return NULL; |
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2845 | jermar | 308 | default: |
309 | case FAT_DENTRY_VALID: |
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310 | dentry_name_canonify(d, name); |
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311 | break; |
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2822 | jermar | 312 | } |
313 | if (strcmp(name, component) == 0) { |
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314 | /* hit */ |
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315 | void *node = fat_node_get(parentp->dev_handle, |
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2831 | jermar | 316 | (fs_index_t)uint16_t_le2host(d->firstc), |
317 | parentp->index); |
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2822 | jermar | 318 | block_put(b); |
319 | return node; |
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320 | } |
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2793 | jermar | 321 | } |
2822 | jermar | 322 | block_put(b); |
2639 | jermar | 323 | } |
2793 | jermar | 324 | |
325 | return NULL; |
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2638 | jermar | 326 | } |
327 | |||
2831 | jermar | 328 | static fs_index_t fat_index_get(void *node) |
329 | { |
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330 | fat_node_t *fnodep = (fat_node_t *)node; |
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331 | if (!fnodep) |
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332 | return 0; |
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333 | return fnodep->index; |
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334 | } |
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335 | |||
336 | static size_t fat_size_get(void *node) |
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337 | { |
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338 | return ((fat_node_t *)node)->size; |
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339 | } |
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340 | |||
341 | static unsigned fat_lnkcnt_get(void *node) |
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342 | { |
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343 | return ((fat_node_t *)node)->lnkcnt; |
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344 | } |
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345 | |||
2845 | jermar | 346 | static bool fat_has_children(void *node) |
347 | { |
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348 | fat_node_t *nodep = (fat_node_t *)node; |
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349 | unsigned bps; |
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350 | unsigned dps; |
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351 | unsigned blocks; |
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352 | block_t *b; |
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353 | unsigned i, j; |
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354 | |||
355 | if (nodep->type != FAT_DIRECTORY) |
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356 | return false; |
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357 | |||
358 | bps = fat_bps_get(nodep->dev_handle); |
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359 | dps = bps / sizeof(fat_dentry_t); |
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360 | |||
361 | blocks = nodep->size / bps + (nodep->size % bps != 0); |
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362 | |||
363 | for (i = 0; i < blocks; i++) { |
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364 | unsigned dentries; |
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365 | fat_dentry_t *d; |
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366 | |||
367 | b = fat_block_get(nodep->dev_handle, nodep->index, i); |
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368 | dentries = (i == blocks - 1) ? |
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369 | nodep->size % sizeof(fat_dentry_t) : |
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370 | dps; |
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371 | for (j = 0; j < dentries; j++) { |
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372 | d = ((fat_dentry_t *)b->data) + j; |
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373 | switch (fat_classify_dentry(d)) { |
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374 | case FAT_DENTRY_SKIP: |
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375 | continue; |
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376 | case FAT_DENTRY_LAST: |
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377 | block_put(b); |
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378 | return false; |
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379 | default: |
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380 | case FAT_DENTRY_VALID: |
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381 | block_put(b); |
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382 | return true; |
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383 | } |
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384 | block_put(b); |
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385 | return true; |
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386 | } |
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387 | block_put(b); |
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388 | } |
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389 | |||
390 | return false; |
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391 | } |
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392 | |||
2844 | jermar | 393 | static void *fat_root_get(dev_handle_t dev_handle) |
394 | { |
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395 | return fat_node_get(dev_handle, 0, 0); |
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396 | } |
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397 | |||
398 | static char fat_plb_get_char(unsigned pos) |
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399 | { |
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400 | return fat_reg.plb_ro[pos % PLB_SIZE]; |
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401 | } |
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402 | |||
2831 | jermar | 403 | static bool fat_is_directory(void *node) |
404 | { |
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405 | return ((fat_node_t *)node)->type == FAT_DIRECTORY; |
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406 | } |
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407 | |||
408 | static bool fat_is_file(void *node) |
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409 | { |
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410 | return ((fat_node_t *)node)->type == FAT_FILE; |
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411 | } |
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412 | |||
2793 | jermar | 413 | /** libfs operations */ |
414 | libfs_ops_t fat_libfs_ops = { |
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415 | .match = fat_match, |
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416 | .node_get = fat_node_get, |
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417 | .create = NULL, |
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418 | .destroy = NULL, |
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419 | .link = NULL, |
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420 | .unlink = NULL, |
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2831 | jermar | 421 | .index_get = fat_index_get, |
422 | .size_get = fat_size_get, |
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423 | .lnkcnt_get = fat_lnkcnt_get, |
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2845 | jermar | 424 | .has_children = fat_has_children, |
2844 | jermar | 425 | .root_get = fat_root_get, |
426 | .plb_get_char = fat_plb_get_char, |
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2831 | jermar | 427 | .is_directory = fat_is_directory, |
428 | .is_file = fat_is_file |
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2793 | jermar | 429 | }; |
430 | |||
2627 | jermar | 431 | void fat_lookup(ipc_callid_t rid, ipc_call_t *request) |
432 | { |
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2793 | jermar | 433 | libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request); |
2627 | jermar | 434 | } |
435 | |||
436 | /** |
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437 | * @} |
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438 | */ |