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  1. /*
  2.  * Copyright (c) 2007 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    tmpfs_ops.c
  35.  * @brief   Implementation of VFS operations for the TMPFS file system
  36.  *      server.
  37.  */
  38.  
  39. #include "tmpfs.h"
  40. #include "../../vfs/vfs.h"
  41. #include <ipc/ipc.h>
  42. #include <async.h>
  43. #include <errno.h>
  44. #include <atomic.h>
  45. #include <stdlib.h>
  46. #include <string.h>
  47. #include <stdio.h>
  48.  
  49. #define PLB_GET_CHAR(i)     (tmpfs_reg.plb_ro[(i) % PLB_SIZE])
  50.  
  51. unsigned tmpfs_next_index = 1;
  52.  
  53. static void tmpfs_dentry_initialize(tmpfs_dentry_t *dentry)
  54. {
  55.     dentry->index = 0;
  56.     dentry->parent = NULL;
  57.     dentry->sibling = NULL;
  58.     dentry->child = NULL;
  59.     dentry->name = NULL;
  60.     dentry->type = TMPFS_NONE;
  61.     dentry->size = 0;
  62.     dentry->data = NULL;
  63. }
  64.  
  65. /*
  66.  * For now, we don't distinguish between different dev_handles/instances. All
  67.  * requests resolve to the only instance, rooted in the following variable.
  68.  */
  69. static tmpfs_dentry_t *root;
  70.  
  71. static bool tmpfs_init(void)
  72. {
  73.     root = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
  74.     if (!root) {
  75.         return false;
  76.     }
  77.     tmpfs_dentry_initialize(root);
  78.     root->index = tmpfs_next_index++;
  79.     root->name = "";
  80.     root->type = TMPFS_DIRECTORY;
  81.  
  82.     /*
  83.      * This is only for debugging. Once we can create files and directories
  84.      * using VFS, we can get rid of this.
  85.      */
  86.     tmpfs_dentry_t *d;
  87.     d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
  88.     if (!d) {
  89.         free(root);
  90.         root = NULL;
  91.         return false;
  92.     }
  93.     tmpfs_dentry_initialize(d);
  94.     d->index = tmpfs_next_index++;
  95.     root->child = d;
  96.     d->parent = root;
  97.     d->type = TMPFS_DIRECTORY;
  98.     d->name = "dir1";
  99.  
  100.     d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
  101.     if (!d) {
  102.         free(root->child);
  103.         free(root);
  104.         root = NULL;
  105.         return false;
  106.     }
  107.     tmpfs_dentry_initialize(d);
  108.     d->index = tmpfs_next_index++;
  109.     root->child->sibling = d;
  110.     d->parent = root;
  111.     d->type = TMPFS_DIRECTORY;
  112.     d->name = "dir2";
  113.    
  114.     d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
  115.     if (!d) {
  116.         free(root->child->sibling);
  117.         free(root->child);
  118.         free(root);
  119.         root = NULL;
  120.         return false;
  121.     }
  122.     tmpfs_dentry_initialize(d);
  123.     d->index = tmpfs_next_index++;
  124.     root->child->child = d;
  125.     d->parent = root->child;
  126.     d->type = TMPFS_FILE;
  127.     d->name = "file1";
  128.     d->data = "This is the contents of /dir1/file1.\n";
  129.     d->size = strlen(d->data);
  130.  
  131.     d = (tmpfs_dentry_t *) malloc(sizeof(tmpfs_dentry_t));
  132.     if (!d) {
  133.         free(root->child->sibling);
  134.         free(root->child->child);
  135.         free(root->child);
  136.         free(root);
  137.         root = NULL;
  138.         return false;
  139.     }
  140.     tmpfs_dentry_initialize(d);
  141.     d->index = tmpfs_next_index++;
  142.     root->child->sibling->child = d;
  143.     d->parent = root->child->sibling;
  144.     d->type = TMPFS_FILE;
  145.     d->name = "file2";
  146.     d->data = "This is the contents of /dir2/file2.\n";
  147.     d->size = strlen(d->data);
  148.  
  149.     return true;
  150. }
  151.  
  152. /** Compare one component of path to a directory entry.
  153.  *
  154.  * @param dentry    Directory entry to compare the path component with.
  155.  * @param start     Index into PLB where the path component starts.
  156.  * @param last      Index of the last character of the path in PLB.
  157.  *
  158.  * @return      Zero on failure or delta such that (index + delta) %
  159.  *          PLB_SIZE points to the first unprocessed character in
  160.  *          PLB which comprises the path.
  161.  */
  162. static unsigned match_path_component(tmpfs_dentry_t *dentry, unsigned start,
  163.     unsigned last)
  164. {
  165.     int i, j;
  166.     size_t namelen;
  167.  
  168.     namelen = strlen(dentry->name);
  169.  
  170.     if (last < start)
  171.         last += PLB_SIZE;
  172.  
  173.     for (i = 0, j = start; i < namelen && j <= last; i++, j++) {
  174.         if (dentry->name[i] != PLB_GET_CHAR(j))
  175.             return 0;
  176.     }
  177.    
  178.     if (i != namelen)
  179.         return 0;
  180.     if (j < last && PLB_GET_CHAR(j) != '/')
  181.         return 0;
  182.     if (j == last)
  183.             return 0;
  184.    
  185.     return (j - start);
  186. }
  187.  
  188. void tmpfs_lookup(ipc_callid_t rid, ipc_call_t *request)
  189. {
  190.     unsigned next = IPC_GET_ARG1(*request);
  191.     unsigned last = IPC_GET_ARG2(*request);
  192.     int dev_handle = IPC_GET_ARG3(*request);
  193.  
  194.     if (last < next)
  195.         last += PLB_SIZE;
  196.  
  197.     if (!root && !tmpfs_init()) {
  198.         ipc_answer_0(rid, ENOMEM);
  199.         return;
  200.     }
  201.  
  202.     tmpfs_dentry_t *dtmp = root->child;
  203.     tmpfs_dentry_t *dcur = root;
  204.  
  205.     bool hit = true;
  206.    
  207.     if (PLB_GET_CHAR(next) == '/')
  208.         next++;     /* eat slash */
  209.    
  210.     while (next <= last) {
  211.         unsigned delta;
  212.         hit = false;
  213.         do {
  214.             delta = match_path_component(dtmp, next, last);
  215.             if (!delta) {
  216.                 dtmp = dtmp->sibling;
  217.             } else {
  218.                 hit = true;
  219.                 next += delta;
  220.                 next++;     /* eat slash */
  221.                 dcur = dtmp;
  222.                 dtmp = dtmp->child;
  223.             }  
  224.         } while (delta == 0 && dtmp);
  225.         if (!hit) {
  226.             ipc_answer_3(rid, ENOENT, tmpfs_reg.fs_handle,
  227.                 dev_handle, dcur->index);
  228.             return;
  229.         }
  230.     }
  231.  
  232.     ipc_answer_3(rid, EOK, tmpfs_reg.fs_handle, dev_handle, dcur->index);
  233. }
  234.  
  235. /**
  236.  * @}
  237.  */
  238.