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  1. /*
  2.  * Copyright (c) 2008 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup fs
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file    fat_ops.c
  35.  * @brief   Implementation of VFS operations for the FAT file system server.
  36.  */
  37.  
  38. #include "fat.h"
  39. #include "../../vfs/vfs.h"
  40. #include <libfs.h>
  41. #include <ipc/ipc.h>
  42. #include <async.h>
  43. #include <errno.h>
  44. #include <string.h>
  45. #include <byteorder.h>
  46.  
  47. #define FAT_NAME_LEN        8
  48. #define FAT_EXT_LEN     3
  49.  
  50. #define FAT_PAD         ' '
  51.  
  52. #define FAT_DENTRY_UNUSED   0x00
  53. #define FAT_DENTRY_E5_ESC   0x05
  54. #define FAT_DENTRY_DOT      0x2e
  55. #define FAT_DENTRY_ERASED   0xe5
  56.  
  57. static void dentry_name_canonify(fat_dentry_t *d, char *buf)
  58. {
  59.     int i;
  60.  
  61.     for (i = 0; i < FAT_NAME_LEN; i++) {
  62.         if (d->name[i] == FAT_PAD) {
  63.             buf++;
  64.             break;
  65.         }
  66.         if (d->name[i] == FAT_DENTRY_E5_ESC)
  67.             *buf++ = 0xe5;
  68.         else
  69.             *buf++ = d->name[i];
  70.     }
  71.     if (d->ext[0] != FAT_PAD)
  72.         *buf++ = '.';
  73.     for (i = 0; i < FAT_EXT_LEN; i++) {
  74.         if (d->ext[i] == FAT_PAD) {
  75.             *buf = '\0';
  76.             return;
  77.         }
  78.         if (d->ext[i] == FAT_DENTRY_E5_ESC)
  79.             *buf++ = 0xe5;
  80.         else
  81.             *buf++ = d->ext[i];
  82.     }
  83. }
  84.  
  85. static fat_dentry_t *fat_dentry_get(fat_node_t *dirnode, unsigned idx)
  86. {
  87.     return NULL;    /* TODO */
  88. }
  89.  
  90. static void fat_dentry_put(fat_dentry_t *dentry)
  91. {
  92.     /* TODO */
  93. }
  94.  
  95. static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
  96. {
  97.     return NULL;    /* TODO */
  98. }
  99.  
  100. static void *fat_match(void *prnt, const char *component)
  101. {
  102.     fat_node_t *parentp = (fat_node_t *)prnt;
  103.     char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
  104.     unsigned i;
  105.     unsigned dentries;
  106.     fat_dentry_t *d;
  107.  
  108.     dentries = parentp->size / sizeof(fat_dentry_t);
  109.     for (i = 0; i < dentries; i++) {
  110.         d = fat_dentry_get(parentp, i);
  111.         if (d->attr & FAT_ATTR_VOLLABEL) {
  112.             /* volume label entry */
  113.             fat_dentry_put(d);
  114.             continue;
  115.         }
  116.         if (d->name[0] == FAT_DENTRY_ERASED) {
  117.             /* not-currently-used entry */
  118.             fat_dentry_put(d);
  119.             continue;
  120.         }
  121.         if (d->name[0] == FAT_DENTRY_UNUSED) {
  122.             /* never used entry */
  123.             fat_dentry_put(d);
  124.             break;
  125.         }
  126.         if (d->name[0] == FAT_DENTRY_DOT) {
  127.             /*
  128.              * Most likely '.' or '..'.
  129.              * It cannot occur in a regular file name.
  130.              */
  131.             fat_dentry_put(d);
  132.             continue;
  133.         }
  134.        
  135.         dentry_name_canonify(d, name);
  136.         if (strcmp(name, component) == 0) {
  137.             /* hit */
  138.             void *node = fat_node_get(parentp->dev_handle,
  139.                 (fs_index_t)uint16_t_le2host(d->firstc));
  140.             fat_dentry_put(d);
  141.             return node;
  142.  
  143.         } else {
  144.             /* miss */
  145.             fat_dentry_put(d);
  146.         }
  147.     }
  148.  
  149.     return NULL;
  150. }
  151.  
  152. /** libfs operations */
  153. libfs_ops_t fat_libfs_ops = {
  154.     .match = fat_match,
  155.     .node_get = fat_node_get,
  156.     .create = NULL,
  157.     .destroy = NULL,
  158.     .link = NULL,
  159.     .unlink = NULL,
  160.     .index_get = NULL,
  161.     .size_get = NULL,
  162.     .lnkcnt_get = NULL,
  163.     .has_children = NULL,
  164.     .root_get = NULL,
  165.     .plb_get_char = NULL,
  166.     .is_directory = NULL,
  167.     .is_file = NULL
  168. };
  169.  
  170. void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
  171. {
  172.     libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
  173. }
  174.  
  175. /**
  176.  * @}
  177.  */
  178.