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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 | |
2831 | jermar | 50 | /** Hash table of FAT in-core nodes. */ |
51 | hash_table_t fin_hash; |
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52 | |||
53 | /** List of free FAT in-core nodes. */ |
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54 | link_t ffn_head; |
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55 | |||
2638 | jermar | 56 | #define FAT_NAME_LEN 8 |
57 | #define FAT_EXT_LEN 3 |
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58 | |||
59 | #define FAT_PAD ' ' |
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60 | |||
61 | #define FAT_DENTRY_UNUSED 0x00 |
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62 | #define FAT_DENTRY_E5_ESC 0x05 |
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63 | #define FAT_DENTRY_DOT 0x2e |
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64 | #define FAT_DENTRY_ERASED 0xe5 |
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65 | |||
2793 | jermar | 66 | static void dentry_name_canonify(fat_dentry_t *d, char *buf) |
2638 | jermar | 67 | { |
2793 | jermar | 68 | int i; |
2639 | jermar | 69 | |
2793 | jermar | 70 | for (i = 0; i < FAT_NAME_LEN; i++) { |
71 | if (d->name[i] == FAT_PAD) { |
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72 | buf++; |
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73 | break; |
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2639 | jermar | 74 | } |
2793 | jermar | 75 | if (d->name[i] == FAT_DENTRY_E5_ESC) |
76 | *buf++ = 0xe5; |
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77 | else |
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78 | *buf++ = d->name[i]; |
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79 | } |
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80 | if (d->ext[0] != FAT_PAD) |
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81 | *buf++ = '.'; |
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82 | for (i = 0; i < FAT_EXT_LEN; i++) { |
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83 | if (d->ext[i] == FAT_PAD) { |
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84 | *buf = '\0'; |
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85 | return; |
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86 | } |
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87 | if (d->ext[i] == FAT_DENTRY_E5_ESC) |
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88 | *buf++ = 0xe5; |
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89 | else |
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90 | *buf++ = d->ext[i]; |
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91 | } |
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92 | } |
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93 | |||
2822 | jermar | 94 | /* TODO and also move somewhere else */ |
95 | typedef struct { |
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96 | void *data; |
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97 | } block_t; |
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98 | |||
99 | static block_t *block_get(dev_handle_t dev_handle, off_t offset) |
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2793 | jermar | 100 | { |
101 | return NULL; /* TODO */ |
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102 | } |
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103 | |||
2831 | jermar | 104 | static block_t *fat_block_get(dev_handle_t dev_handle, fs_index_t index, |
105 | off_t offset) { |
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2822 | jermar | 106 | return NULL; /* TODO */ |
107 | } |
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108 | |||
109 | static void block_put(block_t *block) |
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2793 | jermar | 110 | { |
111 | /* TODO */ |
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112 | } |
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113 | |||
2831 | jermar | 114 | static void fat_node_initialize(fat_node_t *node) |
2793 | jermar | 115 | { |
2831 | jermar | 116 | node->type = 0; |
117 | node->index = 0; |
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118 | node->pindex = 0; |
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119 | node->dev_handle = 0; |
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120 | link_initialize(&node->fin_link); |
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121 | link_initialize(&node->ffn_link); |
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122 | node->size = 0; |
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123 | node->lnkcnt = 0; |
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124 | node->refcnt = 0; |
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125 | node->dirty = false; |
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2793 | jermar | 126 | } |
127 | |||
2831 | jermar | 128 | static void fat_sync_node(fat_node_t *node) |
129 | { |
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130 | /* TODO */ |
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131 | } |
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132 | |||
133 | static void * |
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134 | fat_node_get(dev_handle_t dev_handle, fs_index_t index, fs_index_t pindex) |
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135 | { |
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136 | link_t *lnk; |
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137 | fat_node_t *node = NULL; |
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138 | block_t *bb; |
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139 | block_t *b; |
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140 | fat_dentry_t *d; |
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141 | unsigned bps; /* bytes per sector */ |
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142 | unsigned dps; /* dentries per sector */ |
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143 | |||
144 | unsigned long key[] = { |
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145 | dev_handle, |
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146 | index |
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147 | }; |
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148 | |||
149 | lnk = hash_table_find(&fin_hash, key); |
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150 | if (lnk) { |
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151 | /* |
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152 | * The in-core node was found in the hash table. |
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153 | */ |
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154 | node = hash_table_get_instance(lnk, fat_node_t, fin_link); |
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155 | if (!node->refcnt++) |
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156 | list_remove(&node->ffn_link); |
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157 | return (void *) node; |
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158 | } |
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159 | |||
160 | if (!list_empty(&ffn_head)) { |
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161 | /* |
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162 | * We are going to reuse a node from the free list. |
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163 | */ |
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164 | lnk = ffn_head.next; |
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165 | list_remove(lnk); |
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166 | node = list_get_instance(lnk, fat_node_t, ffn_link); |
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167 | assert(!node->refcnt); |
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168 | if (node->dirty) |
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169 | fat_sync_node(node); |
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170 | } else { |
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171 | /* |
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172 | * We need to allocate a new node. |
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173 | */ |
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174 | node = malloc(sizeof(fat_node_t)); |
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175 | if (!node) |
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176 | return NULL; |
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177 | } |
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178 | fat_node_initialize(node); |
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179 | |||
180 | if (!pindex) { |
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181 | |||
182 | } else { |
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183 | } |
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184 | |||
185 | } |
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186 | |||
2822 | jermar | 187 | #define BS_BLOCK 0 |
188 | |||
2793 | jermar | 189 | static void *fat_match(void *prnt, const char *component) |
190 | { |
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191 | fat_node_t *parentp = (fat_node_t *)prnt; |
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192 | char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1]; |
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2822 | jermar | 193 | unsigned i, j; |
2828 | jermar | 194 | unsigned bps; /* bytes per sector */ |
2822 | jermar | 195 | unsigned dps; /* dentries per sector */ |
196 | unsigned blocks; |
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2793 | jermar | 197 | fat_dentry_t *d; |
2822 | jermar | 198 | block_t *bb; |
199 | block_t *b; |
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2793 | jermar | 200 | |
2822 | jermar | 201 | bb = block_get(parentp->dev_handle, BS_BLOCK); |
202 | if (!bb) |
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203 | return NULL; |
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2828 | jermar | 204 | bps = uint16_t_le2host(((fat_bs_t *)bb->data)->bps); |
2822 | jermar | 205 | block_put(bb); |
2828 | jermar | 206 | dps = bps / sizeof(fat_dentry_t); |
207 | blocks = parentp->size / bps + (parentp->size % bps != 0); |
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2822 | jermar | 208 | for (i = 0; i < blocks; i++) { |
209 | unsigned dentries; |
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2793 | jermar | 210 | |
2831 | jermar | 211 | b = fat_block_get(parentp->dev_handle, parentp->index, i); |
2822 | jermar | 212 | if (!b) |
213 | return NULL; |
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2793 | jermar | 214 | |
2822 | jermar | 215 | dentries = (i == blocks - 1) ? |
216 | parentp->size % sizeof(fat_dentry_t) : |
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217 | dps; |
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218 | for (j = 0; j < dentries; j++) { |
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219 | d = ((fat_dentry_t *)b->data) + j; |
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220 | if (d->attr & FAT_ATTR_VOLLABEL) { |
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221 | /* volume label entry */ |
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222 | continue; |
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223 | } |
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224 | if (d->name[0] == FAT_DENTRY_ERASED) { |
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225 | /* not-currently-used entry */ |
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226 | continue; |
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227 | } |
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228 | if (d->name[0] == FAT_DENTRY_UNUSED) { |
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229 | /* never used entry */ |
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230 | block_put(b); |
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231 | return NULL; |
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232 | } |
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233 | if (d->name[0] == FAT_DENTRY_DOT) { |
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234 | /* |
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235 | * Most likely '.' or '..'. |
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236 | * It cannot occur in a regular file name. |
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237 | */ |
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238 | continue; |
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239 | } |
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240 | |||
241 | dentry_name_canonify(d, name); |
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242 | if (strcmp(name, component) == 0) { |
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243 | /* hit */ |
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244 | void *node = fat_node_get(parentp->dev_handle, |
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2831 | jermar | 245 | (fs_index_t)uint16_t_le2host(d->firstc), |
246 | parentp->index); |
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2822 | jermar | 247 | block_put(b); |
248 | return node; |
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249 | } |
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2793 | jermar | 250 | } |
2822 | jermar | 251 | block_put(b); |
2639 | jermar | 252 | } |
2793 | jermar | 253 | |
254 | return NULL; |
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2638 | jermar | 255 | } |
256 | |||
2831 | jermar | 257 | static fs_index_t fat_index_get(void *node) |
258 | { |
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259 | fat_node_t *fnodep = (fat_node_t *)node; |
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260 | if (!fnodep) |
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261 | return 0; |
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262 | return fnodep->index; |
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263 | } |
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264 | |||
265 | static size_t fat_size_get(void *node) |
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266 | { |
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267 | return ((fat_node_t *)node)->size; |
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268 | } |
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269 | |||
270 | static unsigned fat_lnkcnt_get(void *node) |
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271 | { |
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272 | return ((fat_node_t *)node)->lnkcnt; |
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273 | } |
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274 | |||
275 | static bool fat_is_directory(void *node) |
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276 | { |
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277 | return ((fat_node_t *)node)->type == FAT_DIRECTORY; |
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278 | } |
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279 | |||
280 | static bool fat_is_file(void *node) |
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281 | { |
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282 | return ((fat_node_t *)node)->type == FAT_FILE; |
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283 | } |
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284 | |||
2793 | jermar | 285 | /** libfs operations */ |
286 | libfs_ops_t fat_libfs_ops = { |
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287 | .match = fat_match, |
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288 | .node_get = fat_node_get, |
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289 | .create = NULL, |
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290 | .destroy = NULL, |
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291 | .link = NULL, |
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292 | .unlink = NULL, |
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2831 | jermar | 293 | .index_get = fat_index_get, |
294 | .size_get = fat_size_get, |
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295 | .lnkcnt_get = fat_lnkcnt_get, |
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2793 | jermar | 296 | .has_children = NULL, |
297 | .root_get = NULL, |
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298 | .plb_get_char = NULL, |
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2831 | jermar | 299 | .is_directory = fat_is_directory, |
300 | .is_file = fat_is_file |
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2793 | jermar | 301 | }; |
302 | |||
2627 | jermar | 303 | void fat_lookup(ipc_callid_t rid, ipc_call_t *request) |
304 | { |
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2793 | jermar | 305 | libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request); |
2627 | jermar | 306 | } |
307 | |||
308 | /** |
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309 | * @} |
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310 | */ |