Subversion Repositories HelenOS

Rev

Rev 2643 | Rev 2796 | Go to most recent revision | Blame | Compare with Previous | Last modification | View Log | Download | RSS feed

  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.  
  46. #define FAT_NAME_LEN        8
  47. #define FAT_EXT_LEN     3
  48.  
  49. #define FAT_PAD         ' '
  50.  
  51. #define FAT_DENTRY_UNUSED   0x00
  52. #define FAT_DENTRY_E5_ESC   0x05
  53. #define FAT_DENTRY_DOT      0x2e
  54. #define FAT_DENTRY_ERASED   0xe5
  55.  
  56. static void dentry_name_canonify(fat_dentry_t *d, char *buf)
  57. {
  58.     int i;
  59.  
  60.     for (i = 0; i < FAT_NAME_LEN; i++) {
  61.         if (d->name[i] == FAT_PAD) {
  62.             buf++;
  63.             break;
  64.         }
  65.         if (d->name[i] == FAT_DENTRY_E5_ESC)
  66.             *buf++ = 0xe5;
  67.         else
  68.             *buf++ = d->name[i];
  69.     }
  70.     if (d->ext[0] != FAT_PAD)
  71.         *buf++ = '.';
  72.     for (i = 0; i < FAT_EXT_LEN; i++) {
  73.         if (d->ext[i] == FAT_PAD) {
  74.             *buf = '\0';
  75.             return;
  76.         }
  77.         if (d->ext[i] == FAT_DENTRY_E5_ESC)
  78.             *buf++ = 0xe5;
  79.         else
  80.             *buf++ = d->ext[i];
  81.     }
  82. }
  83.  
  84. static fat_dentry_t *fat_dentry_get(fat_node_t *dirnode, unsigned idx)
  85. {
  86.     return NULL;    /* TODO */
  87. }
  88.  
  89. static void fat_dentry_put(fat_dentry_t *dentry)
  90. {
  91.     /* TODO */
  92. }
  93.  
  94. static void *fat_node_get(dev_handle_t dev_handle, fs_index_t index)
  95. {
  96.     return NULL;    /* TODO */
  97. }
  98.  
  99. static void *fat_match(void *prnt, const char *component)
  100. {
  101.     fat_node_t *parentp = (fat_node_t *)prnt;
  102.     char name[FAT_NAME_LEN + 1 + FAT_EXT_LEN + 1];
  103.     unsigned i;
  104.     unsigned dentries;
  105.     fat_dentry_t *d;
  106.  
  107.     dentries = parentp->size / sizeof(fat_dentry_t);
  108.     for (i = 0; i < dentries; i++) {
  109.         d = fat_dentry_get(parentp, i);
  110.         if (d->attr & FAT_ATTR_VOLLABEL) {
  111.             /* volume label entry */
  112.             fat_dentry_put(d);
  113.             continue;
  114.         }
  115.         if (d->name[0] == FAT_DENTRY_ERASED) {
  116.             /* not-currently-used entry */
  117.             fat_dentry_put(d);
  118.             continue;
  119.         }
  120.         if (d->name[0] == FAT_DENTRY_UNUSED) {
  121.             /* never used entry */
  122.             fat_dentry_put(d);
  123.             break;
  124.         }
  125.         if (d->name[0] == FAT_DENTRY_DOT) {
  126.             /*
  127.              * Most likely '.' or '..'.
  128.              * It cannot occur in a regular file name.
  129.              */
  130.             fat_dentry_put(d);
  131.             continue;
  132.         }
  133.        
  134.         dentry_name_canonify(d, name);
  135.         if (strcmp(name, component) == 0) {
  136.             /* hit */
  137.             void *node = fat_node_get(parentp->dev_handle,
  138.                 (fs_index_t)d->firstc);
  139.             fat_dentry_put(d);
  140.             return node;
  141.  
  142.         } else {
  143.             /* miss */
  144.             fat_dentry_put(d);
  145.         }
  146.     }
  147.  
  148.     return NULL;
  149. }
  150.  
  151. /** libfs operations */
  152. libfs_ops_t fat_libfs_ops = {
  153.     .match = fat_match,
  154.     .node_get = fat_node_get,
  155.     .create = NULL,
  156.     .destroy = NULL,
  157.     .link = NULL,
  158.     .unlink = NULL,
  159.     .index_get = NULL,
  160.     .size_get = NULL,
  161.     .lnkcnt_get = NULL,
  162.     .has_children = NULL,
  163.     .root_get = NULL,
  164.     .plb_get_char = NULL,
  165.     .is_directory = NULL,
  166.     .is_file = NULL
  167. };
  168.  
  169. void fat_lookup(ipc_callid_t rid, ipc_call_t *request)
  170. {
  171.     libfs_lookup(&fat_libfs_ops, fat_reg.fs_handle, rid, request);
  172. }
  173.  
  174. /**
  175.  * @}
  176.  */
  177.