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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    vfs.c
  35.  * @brief   VFS_OPEN method.
  36.  */
  37.  
  38. #include <ipc/ipc.h>
  39. #include <async.h>
  40. #include <errno.h>
  41. #include <stdlib.h>
  42. #include <string.h>
  43. #include <bool.h>
  44. #include <futex.h>
  45. #include <libadt/list.h>
  46. #include <sys/types.h>
  47. #include "vfs.h"
  48.  
  49. /** Per-connection futex protecting the files array. */
  50. __thread atomic_t files_futex = FUTEX_INITIALIZER;
  51.  
  52. /**
  53.  * This is a per-connection table of open files.
  54.  * Our assumption is that each client opens only one connection and therefore
  55.  * there is one table of open files per task. However, this may not be the case
  56.  * and the client can open more connections to VFS. In that case, there will be
  57.  * several tables and several file handle name spaces per task. Besides of this,
  58.  * the functionality will stay unchanged. So unless the client knows what it is
  59.  * doing, it should open one connection to VFS only.
  60.  *
  61.  * Allocation of the open files table is deferred until the client makes the
  62.  * first VFS_OPEN operation.
  63.  */
  64. __thread vfs_file_t *files = NULL;
  65.  
  66. /** Initialize the table of open files. */
  67. static bool vfs_conn_open_files_init(void)
  68. {
  69.     futex_down(&files_futex);
  70.     if (!files) {
  71.         files = malloc(MAX_OPEN_FILES * sizeof(vfs_file_t));
  72.         if (!files) {
  73.             futex_up(&files_futex);
  74.             return false;
  75.         }
  76.         memset(files, 0, MAX_OPEN_FILES * sizeof(vfs_file_t));
  77.     }
  78.     futex_up(&files_futex);
  79.     return true;
  80. }
  81.  
  82. void vfs_open(ipc_callid_t rid, ipc_call_t *request)
  83. {
  84.     if (!vfs_conn_open_files_init()) {
  85.         ipc_answer_fast_0(rid, ENOMEM);
  86.         return;
  87.     }
  88. }
  89.  
  90. /**
  91.  * @}
  92.  */
  93.