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  1. /*
  2.  * Copyright (c) 2006 Martin Decky
  3.  * Copyright (c) 2008 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. };
  53.  
  54. fs_reg_t fat_reg;
  55.  
  56. /**
  57.  * This connection fibril processes VFS requests from VFS.
  58.  *
  59.  * In order to support simultaneous VFS requests, our design is as follows.
  60.  * The connection fibril accepts VFS requests from VFS. If there is only one
  61.  * instance of the fibril, VFS will need to serialize all VFS requests it sends
  62.  * to FAT. To overcome this bottleneck, VFS can send FAT the IPC_M_CONNECT_ME_TO
  63.  * call. In that case, a new connection fibril will be created, which in turn
  64.  * will accept the call. Thus, a new phone will be opened for VFS.
  65.  *
  66.  * There are few issues with this arrangement. First, VFS can run out of
  67.  * available phones. In that case, VFS can close some other phones or use one
  68.  * phone for more serialized requests. Similarily, FAT can refuse to duplicate
  69.  * the connection. VFS should then just make use of already existing phones and
  70.  * route its requests through them. To avoid paying the fibril creation price
  71.  * upon each request, FAT might want to keep the connections open after the
  72.  * request has been completed.
  73.  */
  74. static void fat_connection(ipc_callid_t iid, ipc_call_t *icall)
  75. {
  76.     if (iid) {
  77.         /*
  78.          * This only happens for connections opened by
  79.          * IPC_M_CONNECT_ME_TO calls as opposed to callback connections
  80.          * created by IPC_M_CONNECT_TO_ME.
  81.          */
  82.         ipc_answer_0(iid, EOK);
  83.     }
  84.    
  85.     dprintf("VFS-FAT connection established.\n");
  86.     while (1) {
  87.         ipc_callid_t callid;
  88.         ipc_call_t call;
  89.    
  90.         callid = async_get_call(&call);
  91.         switch  (IPC_GET_METHOD(call)) {
  92.         case VFS_MOUNTED:
  93.             fat_mounted(callid, &call);
  94.             break;
  95.         case VFS_MOUNT:
  96.             fat_mount(callid, &call);
  97.             break;
  98.         case VFS_LOOKUP:
  99.             fat_lookup(callid, &call);
  100.             break;
  101.         case VFS_READ:
  102.             fat_read(callid, &call);
  103.             break;
  104.         case VFS_WRITE:
  105.             fat_write(callid, &call);
  106.             break;
  107.         case VFS_TRUNCATE:
  108.             fat_truncate(callid, &call);
  109.             break;
  110.         case VFS_DESTROY:
  111.             fat_destroy(callid, &call);
  112.             break;
  113.         default:
  114.             ipc_answer_0(callid, ENOTSUP);
  115.             break;
  116.         }
  117.     }
  118. }
  119.  
  120. int main(int argc, char **argv)
  121. {
  122.     int vfs_phone;
  123.     int rc;
  124.  
  125.     printf("fat: HelenOS FAT file system server.\n");
  126.  
  127.     rc = fat_idx_init();
  128.     if (rc != EOK)
  129.         goto err;
  130.  
  131.     vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0, 0);
  132.     while (vfs_phone < EOK) {
  133.         usleep(10000);
  134.         vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0, 0);
  135.     }
  136.    
  137.     rc = fs_register(vfs_phone, &fat_reg, &fat_vfs_info, fat_connection);
  138.     if (rc != EOK) {
  139.         fat_idx_fini();
  140.         goto err;
  141.     }
  142.    
  143.     dprintf("FAT filesystem registered, fs_handle=%d.\n",
  144.         fat_reg.fs_handle);
  145.  
  146.     async_manager();
  147.     /* not reached */
  148.     return 0;
  149.  
  150. err:
  151.     printf("Failed to register the FAT file system (%d)\n", rc);
  152.     return rc;
  153. }
  154.  
  155. /**
  156.  * @}
  157.  */
  158.