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  1. /*
  2.  * Copyright (c) 2007 Michal Konopa
  3.  * Copyright (c) 2007 Martin Jelen
  4.  * Copyright (c) 2007 Peter Majer
  5.  * Copyright (c) 2007 Jakub Jermar
  6.  * All rights reserved.
  7.  *
  8.  * Redistribution and use in source and binary forms, with or without
  9.  * modification, are permitted provided that the following conditions
  10.  * are met:
  11.  *
  12.  * - Redistributions of source code must retain the above copyright
  13.  *   notice, this list of conditions and the following disclaimer.
  14.  * - Redistributions in binary form must reproduce the above copyright
  15.  *   notice, this list of conditions and the following disclaimer in the
  16.  *   documentation and/or other materials provided with the distribution.
  17.  * - The name of the author may not be used to endorse or promote products
  18.  *   derived from this software without specific prior written permission.
  19.  *
  20.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  21.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  22.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  23.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  24.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  25.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  29.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30.  */
  31.  
  32. /** @addtogroup rd
  33.  * @{
  34.  */
  35.  
  36. /**
  37.  * @file    rd.c
  38.  * @brief   Initial RAM disk for HelenOS.
  39.  */
  40.  
  41. #include <ipc/ipc.h>
  42. #include <ipc/services.h>
  43. #include <ipc/ns.h>
  44. #include <sysinfo.h>
  45. #include <as.h>
  46. #include <ddi.h>
  47. #include <align.h>
  48. #include <bool.h>
  49. #include <errno.h>
  50. #include <async.h>
  51. #include <align.h>
  52. #include <async.h>
  53. #include <futex.h>
  54. #include <stdio.h>
  55. #include <devmap.h>
  56. #include <ipc/bd.h>
  57.  
  58. #define NAME "rd"
  59.  
  60. /** Pointer to the ramdisk's image. */
  61. static void *rd_addr;
  62. /** Size of the ramdisk. */
  63. static size_t rd_size;
  64.  
  65. /**
  66.  * This futex protects the ramdisk's data.
  67.  * If we were to serve multiple requests (read + write or several writes)
  68.  * concurrently (i.e. from two or more threads), each read and write needs to be
  69.  * protected by this futex.
  70.  */
  71. atomic_t rd_futex = FUTEX_INITIALIZER;
  72.  
  73. /** Handle one connection to ramdisk.
  74.  *
  75.  * @param iid       Hash of the request that opened the connection.
  76.  * @param icall     Call data of the request that opened the connection.
  77.  */
  78. static void rd_connection(ipc_callid_t iid, ipc_call_t *icall)
  79. {
  80.     ipc_callid_t callid;
  81.     ipc_call_t call;
  82.     int retval;
  83.     void *fs_va = NULL;
  84.     off_t offset;
  85.     size_t block_size;
  86.     size_t maxblock_size;
  87.  
  88.     /*
  89.      * Answer the first IPC_M_CONNECT_ME_TO call.
  90.      */
  91.     ipc_answer_0(iid, EOK);
  92.  
  93.     /*
  94.      * Now we wait for the client to send us its communication as_area.
  95.      */
  96.     int flags;
  97.     if (ipc_share_out_receive(&callid, &maxblock_size, &flags)) {
  98.         fs_va = as_get_mappable_page(maxblock_size);
  99.         if (fs_va) {
  100.             (void) ipc_share_out_finalize(callid, fs_va);
  101.         } else {
  102.             ipc_answer_0(callid, EHANGUP);
  103.             return;    
  104.         }
  105.     } else {
  106.         /*
  107.          * The client doesn't speak the same protocol.
  108.          * At this point we can't handle protocol variations.
  109.          * Close the connection.
  110.          */
  111.         ipc_answer_0(callid, EHANGUP);
  112.         return;
  113.     }
  114.    
  115.     while (true) {
  116.         callid = async_get_call(&call);
  117.         switch (IPC_GET_METHOD(call)) {
  118.         case IPC_M_PHONE_HUNGUP:
  119.             /*
  120.              * The other side has hung up.
  121.              * Answer the message and exit the fibril.
  122.              */
  123.             ipc_answer_0(callid, EOK);
  124.             return;
  125.         case BD_READ_BLOCK:
  126.             offset = IPC_GET_ARG1(call);
  127.             block_size = IPC_GET_ARG2(call);
  128.             if (block_size > maxblock_size) {
  129.                 /*
  130.                  * Maximum block size exceeded.
  131.                  */
  132.                 retval = ELIMIT;
  133.                 break;
  134.             }
  135.             if (offset * block_size > rd_size - block_size) {
  136.                 /*
  137.                  * Reading past the end of the device.
  138.                  */
  139.                 retval = ELIMIT;
  140.                 break;
  141.             }
  142.             futex_down(&rd_futex);
  143.             memcpy(fs_va, rd_addr + offset * block_size, block_size);
  144.             futex_up(&rd_futex);
  145.             retval = EOK;
  146.             break;
  147.         case BD_WRITE_BLOCK:
  148.             offset = IPC_GET_ARG1(call);
  149.             block_size = IPC_GET_ARG2(call);
  150.             if (block_size > maxblock_size) {
  151.                 /*
  152.                  * Maximum block size exceeded.
  153.                  */
  154.                 retval = ELIMIT;
  155.                 break;
  156.             }
  157.             if (offset * block_size > rd_size - block_size) {
  158.                 /*
  159.                  * Writing past the end of the device.
  160.                  */
  161.                 retval = ELIMIT;
  162.                 break;
  163.             }
  164.             futex_up(&rd_futex);
  165.             memcpy(rd_addr + offset * block_size, fs_va, block_size);
  166.             futex_down(&rd_futex);
  167.             retval = EOK;
  168.             break;
  169.         default:
  170.             /*
  171.              * The client doesn't speak the same protocol.
  172.              * Instead of closing the connection, we just ignore
  173.              * the call. This can be useful if the client uses a
  174.              * newer version of the protocol.
  175.              */
  176.             retval = EINVAL;
  177.             break;
  178.         }
  179.         ipc_answer_0(callid, retval);
  180.     }
  181. }
  182.  
  183. /** Prepare the ramdisk image for operation. */
  184. static bool rd_init(void)
  185. {
  186.     rd_size = sysinfo_value("rd.size");
  187.     void *rd_ph_addr = (void *) sysinfo_value("rd.address.physical");
  188.    
  189.     if (rd_size == 0) {
  190.         printf(NAME ": No RAM disk found\n");
  191.         return false;
  192.     }
  193.    
  194.     rd_addr = as_get_mappable_page(rd_size);
  195.    
  196.     int flags = AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE;
  197.     int retval = physmem_map(rd_ph_addr, rd_addr,
  198.         ALIGN_UP(rd_size, PAGE_SIZE) >> PAGE_WIDTH, flags);
  199.    
  200.     if (retval < 0) {
  201.         printf(NAME ": Error mapping RAM disk\n");
  202.         return false;
  203.     }
  204.    
  205.     printf(NAME ": Found RAM disk at %p, %d bytes\n", rd_ph_addr, rd_size);
  206.    
  207.     int rc = devmap_driver_register(NAME, rd_connection);
  208.     if (rc < 0) {
  209.         printf(NAME ": Unable to register driver (%d)\n", rc);
  210.         return false;
  211.     }
  212.    
  213.     dev_handle_t dev_handle;
  214.     if (devmap_device_register("initrd", &dev_handle) != EOK) {
  215.         devmap_hangup_phone(DEVMAP_DRIVER);
  216.         printf(NAME ": Unable to register device\n");
  217.         return false;
  218.     }
  219.    
  220.     return true;
  221. }
  222.  
  223. int main(int argc, char **argv)
  224. {
  225.     printf(NAME ": HelenOS RAM disk server\n");
  226.    
  227.     if (!rd_init())
  228.         return -1;
  229.    
  230.     printf(NAME ": Accepting connections\n");
  231.     async_manager();
  232.  
  233.     /* Never reached */
  234.     return 0;
  235. }
  236.  
  237. /**
  238.  * @}
  239.  */
  240.