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  1. /*
  2.  * Copyright (c) 2006 Martin Decky
  3.  * Copyright (c) 2007 Jakub Jermar
  4.  * All rights reserved.
  5.  *
  6.  * Redistribution and use in source and binary forms, with or without
  7.  * modification, are permitted provided that the following conditions
  8.  * are met:
  9.  *
  10.  * - Redistributions of source code must retain the above copyright
  11.  *   notice, this list of conditions and the following disclaimer.
  12.  * - Redistributions in binary form must reproduce the above copyright
  13.  *   notice, this list of conditions and the following disclaimer in the
  14.  *   documentation and/or other materials provided with the distribution.
  15.  * - The name of the author may not be used to endorse or promote products
  16.  *   derived from this software without specific prior written permission.
  17.  *
  18.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  22.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  23.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28.  */
  29.  
  30. /** @addtogroup fs
  31.  * @{
  32.  */
  33.  
  34. /**
  35.  * @file    fat.c
  36.  * @brief   FAT file system driver for HelenOS.
  37.  */
  38.  
  39. #include "fat.h"
  40. #include <ipc/ipc.h>
  41. #include <ipc/services.h>
  42. #include <async.h>
  43. #include <errno.h>
  44. #include <unistd.h>
  45. #include <stdio.h>
  46. #include <libfs.h>
  47. #include "../../vfs/vfs.h"
  48.  
  49.  
  50. vfs_info_t fat_vfs_info = {
  51.     .name = "fat",
  52.     .ops = {
  53.         [IPC_METHOD_TO_VFS_OP(VFS_REGISTER)] = VFS_OP_DEFINED,
  54.         [IPC_METHOD_TO_VFS_OP(VFS_MOUNT)] = VFS_OP_DEFINED,
  55.         [IPC_METHOD_TO_VFS_OP(VFS_UNMOUNT)] = VFS_OP_DEFINED,
  56.         [IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] = VFS_OP_DEFINED,
  57.         [IPC_METHOD_TO_VFS_OP(VFS_OPEN)] = VFS_OP_DEFINED,
  58.         [IPC_METHOD_TO_VFS_OP(VFS_CREATE)] = VFS_OP_DEFINED,
  59.         [IPC_METHOD_TO_VFS_OP(VFS_CLOSE)] = VFS_OP_DEFINED,
  60.         [IPC_METHOD_TO_VFS_OP(VFS_READ)] = VFS_OP_DEFINED,
  61.         [IPC_METHOD_TO_VFS_OP(VFS_WRITE)] = VFS_OP_NULL,
  62.         [IPC_METHOD_TO_VFS_OP(VFS_SEEK)] = VFS_OP_DEFAULT
  63.     }
  64. };
  65.  
  66. fs_reg_t fat_reg;
  67.  
  68. /**
  69.  * This connection fibril processes VFS requests from VFS.
  70.  *
  71.  * In order to support simultaneous VFS requests, our design is as follows.
  72.  * The connection fibril accepts VFS requests from VFS. If there is only one
  73.  * instance of the fibril, VFS will need to serialize all VFS requests it sends
  74.  * to FAT. To overcome this bottleneck, VFS can send FAT the IPC_M_CONNECT_ME_TO
  75.  * call. In that case, a new connection fibril will be created, which in turn
  76.  * will accept the call. Thus, a new phone will be opened for VFS.
  77.  *
  78.  * There are few issues with this arrangement. First, VFS can run out of
  79.  * available phones. In that case, VFS can close some other phones or use one
  80.  * phone for more serialized requests. Similarily, FAT can refuse to duplicate
  81.  * the connection. VFS should then just make use of already existing phones and
  82.  * route its requests through them. To avoid paying the fibril creation price
  83.  * upon each request, FAT might want to keep the connections open after the
  84.  * request has been completed.
  85.  */
  86. static void fat_connection(ipc_callid_t iid, ipc_call_t *icall)
  87. {
  88.     if (iid) {
  89.         /*
  90.          * This only happens for connections opened by
  91.          * IPC_M_CONNECT_ME_TO calls as opposed to callback connections
  92.          * created by IPC_M_CONNECT_TO_ME.
  93.          */
  94.         ipc_answer_0(iid, EOK);
  95.     }
  96.    
  97.     dprintf("VFS-FAT connection established.\n");
  98.     while (1) {
  99.         ipc_callid_t callid;
  100.         ipc_call_t call;
  101.    
  102.         callid = async_get_call(&call);
  103.         switch  (IPC_GET_METHOD(call)) {
  104.         case VFS_REGISTER:
  105.             ipc_answer_0(callid, EOK);
  106.             break;
  107.         case VFS_LOOKUP:
  108.             fat_lookup(callid, &call);
  109.             break;
  110.         default:
  111.             ipc_answer_0(callid, ENOTSUP);
  112.             break;
  113.         }
  114.     }
  115. }
  116.  
  117. int main(int argc, char **argv)
  118. {
  119.     int vfs_phone;
  120.  
  121.     printf("FAT: HelenOS FAT file system server.\n");
  122.  
  123.     vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0, 0);
  124.     while (vfs_phone < EOK) {
  125.         usleep(10000);
  126.         vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0, 0);
  127.     }
  128.    
  129.     int rc;
  130.     rc = fs_register(vfs_phone, &fat_reg, &fat_vfs_info, fat_connection);
  131.     if (rc != EOK) {
  132.         printf("Failed to register the FAT file system (%d)\n", rc);
  133.         return rc;
  134.     }
  135.    
  136.     dprintf("FAT filesystem registered, fs_handle=%d.\n",
  137.         fat_reg.fs_handle);
  138.  
  139.     async_manager();
  140.     /* not reached */
  141.     return 0;
  142. }
  143.  
  144. /**
  145.  * @}
  146.  */
  147.