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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 multiplexer for HelenOS.
  36.  */
  37.  
  38. #include <ipc/ipc.h>
  39. #include <ipc/services.h>
  40. #include <async.h>
  41. #include <errno.h>
  42. #include <stdlib.h>
  43. #include <bool.h>
  44. #include "vfs.h"
  45.  
  46. /** Verify the VFS info structure.
  47.  *
  48.  * @param info      Info structure to be verified.
  49.  *
  50.  * @return      Non-zero if the info structure is sane, zero otherwise.
  51.  */
  52. static int vfs_info_sane(vfs_info_t *info)
  53. {
  54.     return 1;   /* XXX */
  55. }
  56.  
  57. /** VFS_REGISTER protocol function.
  58.  *
  59.  * @param rid       Hash of the call with the request.
  60.  * @param request   Call structure with the request.
  61.  */
  62. static void vfs_register(ipc_callid_t rid, ipc_call_t *request)
  63. {
  64.     ipc_callid_t callid;
  65.     ipc_call_t call;
  66.     int rc;
  67.     size_t size;
  68.  
  69.     /*
  70.      * The first call has to be IPC_M_DATA_SEND in which we receive the
  71.      * VFS info structure from the client FS.
  72.      */
  73.     if (!ipc_data_send_accept(&callid, &call, NULL, &size)) {
  74.         /*
  75.          * The client doesn't obey the same protocol as we do.
  76.          */
  77.         ipc_answer_fast(callid, EINVAL, 0, 0);
  78.         ipc_answer_fast(rid, EINVAL, 0, 0);
  79.         return;
  80.     }
  81.    
  82.     /*
  83.      * We know the size of the info structure. See if the client understands
  84.      * this easy concept too.
  85.      */
  86.     if (size != sizeof(vfs_info_t)) {
  87.         /*
  88.          * The client is sending us something, which cannot be
  89.          * the info structure.
  90.          */
  91.         ipc_answer_fast(callid, EINVAL, 0, 0);
  92.         ipc_answer_fast(rid, EINVAL, 0, 0);
  93.         return;
  94.     }
  95.     vfs_info_t *info;
  96.  
  97.     /*
  98.      * Allocate a buffer for the info structure.
  99.      */
  100.     info = (vfs_info_t *) malloc(sizeof(vfs_info_t));
  101.     if (!info) {
  102.         ipc_answer_fast(callid, ENOMEM, 0, 0);
  103.         ipc_answer_fast(rid, ENOMEM, 0, 0);
  104.         return;
  105.     }
  106.        
  107.     rc = ipc_data_send_answer(callid, &call, info, size);
  108.     if (!rc) {
  109.         free(info);
  110.         ipc_answer_fast(callid, rc, 0, 0);
  111.         ipc_answer_fast(rid, rc, 0, 0);
  112.         return;
  113.     }
  114.        
  115.     if (!vfs_info_sane(info)) {
  116.         free(info);
  117.         ipc_answer_fast(callid, EINVAL, 0, 0);
  118.         ipc_answer_fast(rid, EINVAL, 0, 0);
  119.         return;
  120.     }
  121.        
  122. }
  123.  
  124. static void vfs_connection(ipc_callid_t iid, ipc_call_t *icall)
  125. {
  126.     bool keep_on_going = 1;
  127.  
  128.     /*
  129.      * The connection was opened via the IPC_CONNECT_ME_TO call.
  130.      * This call needs to be answered.
  131.      */
  132.     ipc_answer_fast(iid, EOK, 0, 0);
  133.  
  134.     /*
  135.      * Here we enter the main connection fibril loop.
  136.      * The logic behind this loop and the protocol is that we'd like to keep
  137.      * each connection open for a while before we close it. The benefit of
  138.      * this is that the client doesn't have to establish a new connection
  139.      * upon each request.  On the other hand, the client must be ready to
  140.      * re-establish a connection if we hang it up due to reaching of maximum
  141.      * number of requests per connection or due to the client timing out.
  142.      */
  143.      
  144.     while (keep_on_going) {
  145.         ipc_callid_t callid;
  146.         ipc_call_t call;
  147.  
  148.         callid = async_get_call(&call);
  149.        
  150.         switch (IPC_GET_METHOD(call)) {
  151.         case IPC_M_PHONE_HUNGUP:
  152.             keep_on_going = false;
  153.             break;
  154.         case VFS_REGISTER:
  155.             vfs_register(callid, &call);
  156.             keep_on_going = false;
  157.             break;
  158.         case VFS_MOUNT:
  159.         case VFS_UNMOUNT:
  160.         case VFS_OPEN:
  161.         case VFS_CREATE:
  162.         case VFS_CLOSE:
  163.         case VFS_READ:
  164.         case VFS_WRITE:
  165.         case VFS_SEEK:
  166.         default:
  167.             ipc_answer_fast(callid, ENOTSUP, 0, 0);
  168.             break;
  169.         }
  170.     }
  171.  
  172.     /* TODO: cleanup after the client */
  173.    
  174. }
  175.  
  176. int main(int argc, char **argv)
  177. {
  178.     ipcarg_t phonead;
  179.  
  180.     async_set_client_connection(vfs_connection);
  181.     ipc_connect_to_me(PHONE_NS, SERVICE_VFS, 0, &phonead);
  182.     async_manager();
  183.     return 0;
  184. }
  185.  
  186. /**
  187.  * @}
  188.  */
  189.