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  1. /*
  2.  * Copyright (c) 2008 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_register.c
  35.  * @brief
  36.  */
  37.  
  38. #include <ipc/ipc.h>
  39. #include <ipc/services.h>
  40. #include <async.h>
  41. #include <fibril.h>
  42. #include <errno.h>
  43. #include <stdio.h>
  44. #include <stdlib.h>
  45. #include <string.h>
  46. #include <ctype.h>
  47. #include <bool.h>
  48. #include <fibril_sync.h>
  49. #include <adt/list.h>
  50. #include <as.h>
  51. #include <assert.h>
  52. #include <atomic.h>
  53. #include "vfs.h"
  54.  
  55. FIBRIL_CONDVAR_INITIALIZE(fs_head_cv);
  56. FIBRIL_MUTEX_INITIALIZE(fs_head_lock);
  57. LIST_INITIALIZE(fs_head);
  58.  
  59. atomic_t fs_handle_next = {
  60.     .count = 1
  61. };
  62.  
  63. /** Verify the VFS info structure.
  64.  *
  65.  * @param info      Info structure to be verified.
  66.  *
  67.  * @return      Non-zero if the info structure is sane, zero otherwise.
  68.  */
  69. static bool vfs_info_sane(vfs_info_t *info)
  70. {
  71.     int i;
  72.  
  73.     /*
  74.      * Check if the name is non-empty and is composed solely of ASCII
  75.      * characters [a-z]+[a-z0-9_-]*.
  76.      */
  77.     if (!islower(info->name[0])) {
  78.         dprintf("The name doesn't start with a lowercase character.\n");
  79.         return false;
  80.     }
  81.     for (i = 1; i < FS_NAME_MAXLEN; i++) {
  82.         if (!(islower(info->name[i]) || isdigit(info->name[i])) &&
  83.             (info->name[i] != '-') && (info->name[i] != '_')) {
  84.             if (info->name[i] == '\0') {
  85.                 break;
  86.             } else {
  87.                 dprintf("The name contains illegal "
  88.                     "characters.\n");
  89.                 return false;
  90.             }
  91.         }
  92.     }
  93.     /*
  94.      * This check is not redundant. It ensures that the name is
  95.      * NULL-terminated, even if FS_NAME_MAXLEN characters are used.
  96.      */
  97.     if (info->name[i] != '\0') {
  98.         dprintf("The name is not properly NULL-terminated.\n");
  99.         return false;
  100.     }
  101.    
  102.     return true;
  103. }
  104.  
  105. /** VFS_REGISTER protocol function.
  106.  *
  107.  * @param rid       Hash of the call with the request.
  108.  * @param request   Call structure with the request.
  109.  */
  110. void vfs_register(ipc_callid_t rid, ipc_call_t *request)
  111. {
  112.     ipc_callid_t callid;
  113.     ipc_call_t call;
  114.     int rc;
  115.     size_t size;
  116.  
  117.     dprintf("Processing VFS_REGISTER request received from %p.\n",
  118.         request->in_phone_hash);
  119.  
  120.     /*
  121.      * The first call has to be IPC_M_DATA_SEND in which we receive the
  122.      * VFS info structure from the client FS.
  123.      */
  124.     if (!ipc_data_write_receive(&callid, &size)) {
  125.         /*
  126.          * The client doesn't obey the same protocol as we do.
  127.          */
  128.         dprintf("Receiving of VFS info failed.\n");
  129.         ipc_answer_0(callid, EINVAL);
  130.         ipc_answer_0(rid, EINVAL);
  131.         return;
  132.     }
  133.    
  134.     dprintf("VFS info received, size = %d\n", size);
  135.    
  136.     /*
  137.      * We know the size of the VFS info structure. See if the client
  138.      * understands this easy concept too.
  139.      */
  140.     if (size != sizeof(vfs_info_t)) {
  141.         /*
  142.          * The client is sending us something, which cannot be
  143.          * the info structure.
  144.          */
  145.         dprintf("Received VFS info has bad size.\n");
  146.         ipc_answer_0(callid, EINVAL);
  147.         ipc_answer_0(rid, EINVAL);
  148.         return;
  149.     }
  150.  
  151.     /*
  152.      * Allocate and initialize a buffer for the fs_info structure.
  153.      */
  154.     fs_info_t *fs_info;
  155.     fs_info = (fs_info_t *) malloc(sizeof(fs_info_t));
  156.     if (!fs_info) {
  157.         dprintf("Could not allocate memory for FS info.\n");
  158.         ipc_answer_0(callid, ENOMEM);
  159.         ipc_answer_0(rid, ENOMEM);
  160.         return;
  161.     }
  162.     link_initialize(&fs_info->fs_link);
  163.     fibril_mutex_initialize(&fs_info->phone_lock);
  164.        
  165.     rc = ipc_data_write_finalize(callid, &fs_info->vfs_info, size);
  166.     if (rc != EOK) {
  167.         dprintf("Failed to deliver the VFS info into our AS, rc=%d.\n",
  168.             rc);
  169.         free(fs_info);
  170.         ipc_answer_0(callid, rc);
  171.         ipc_answer_0(rid, rc);
  172.         return;
  173.     }
  174.  
  175.     dprintf("VFS info delivered.\n");
  176.        
  177.     if (!vfs_info_sane(&fs_info->vfs_info)) {
  178.         free(fs_info);
  179.         ipc_answer_0(callid, EINVAL);
  180.         ipc_answer_0(rid, EINVAL);
  181.         return;
  182.     }
  183.        
  184.     fibril_mutex_lock(&fs_head_lock);
  185.  
  186.     /*
  187.      * Check for duplicit registrations.
  188.      */
  189.     if (fs_name_to_handle(fs_info->vfs_info.name, false)) {
  190.         /*
  191.          * We already register a fs like this.
  192.          */
  193.         dprintf("FS is already registered.\n");
  194.         fibril_mutex_unlock(&fs_head_lock);
  195.         free(fs_info);
  196.         ipc_answer_0(callid, EEXISTS);
  197.         ipc_answer_0(rid, EEXISTS);
  198.         return;
  199.     }
  200.  
  201.     /*
  202.      * Add fs_info to the list of registered FS's.
  203.      */
  204.     dprintf("Inserting FS into the list of registered file systems.\n");
  205.     list_append(&fs_info->fs_link, &fs_head);
  206.    
  207.     /*
  208.      * Now we want the client to send us the IPC_M_CONNECT_TO_ME call so
  209.      * that a callback connection is created and we have a phone through
  210.      * which to forward VFS requests to it.
  211.      */
  212.     callid = async_get_call(&call);
  213.     if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) {
  214.         dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
  215.         list_remove(&fs_info->fs_link);
  216.         fibril_mutex_unlock(&fs_head_lock);
  217.         free(fs_info);
  218.         ipc_answer_0(callid, EINVAL);
  219.         ipc_answer_0(rid, EINVAL);
  220.         return;
  221.     }
  222.     fs_info->phone = IPC_GET_ARG5(call);
  223.     ipc_answer_0(callid, EOK);
  224.  
  225.     dprintf("Callback connection to FS created.\n");
  226.  
  227.     /*
  228.      * The client will want us to send him the address space area with PLB.
  229.      */
  230.  
  231.     if (!ipc_share_in_receive(&callid, &size)) {
  232.         dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
  233.         list_remove(&fs_info->fs_link);
  234.         fibril_mutex_unlock(&fs_head_lock);
  235.         ipc_hangup(fs_info->phone);
  236.         free(fs_info);
  237.         ipc_answer_0(callid, EINVAL);
  238.         ipc_answer_0(rid, EINVAL);
  239.         return;
  240.     }
  241.    
  242.     /*
  243.      * We can only send the client address space area PLB_SIZE bytes long.
  244.      */
  245.     if (size != PLB_SIZE) {
  246.         dprintf("Client suggests wrong size of PFB, size = %d\n", size);
  247.         list_remove(&fs_info->fs_link);
  248.         fibril_mutex_unlock(&fs_head_lock);
  249.         ipc_hangup(fs_info->phone);
  250.         free(fs_info);
  251.         ipc_answer_0(callid, EINVAL);
  252.         ipc_answer_0(rid, EINVAL);
  253.         return;
  254.     }
  255.  
  256.     /*
  257.      * Commit to read-only sharing the PLB with the client.
  258.      */
  259.     (void) ipc_share_in_finalize(callid, plb,
  260.         AS_AREA_READ | AS_AREA_CACHEABLE);
  261.  
  262.     dprintf("Sharing PLB.\n");
  263.  
  264.     /*
  265.      * That was it. The FS has been registered.
  266.      * In reply to the VFS_REGISTER request, we assign the client file
  267.      * system a global file system handle.
  268.      */
  269.     fs_info->fs_handle = (fs_handle_t) atomic_postinc(&fs_handle_next);
  270.     ipc_answer_1(rid, EOK, (ipcarg_t) fs_info->fs_handle);
  271.    
  272.     fibril_condvar_broadcast(&fs_head_cv);
  273.     fibril_mutex_unlock(&fs_head_lock);
  274.    
  275.     dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n",
  276.         FS_NAME_MAXLEN, fs_info->vfs_info.name, fs_info->fs_handle);
  277. }
  278.  
  279. /** For a given file system handle, implement policy for allocating a phone.
  280.  *
  281.  * @param handle    File system handle.
  282.  *
  283.  * @return      Phone over which a multi-call request can be safely
  284.  *          sent. Return 0 if no phone was found.
  285.  */
  286. int vfs_grab_phone(fs_handle_t handle)
  287. {
  288.     int phone;
  289.  
  290.     /*
  291.      * For now, we don't try to be very clever and very fast.  We simply
  292.      * lookup the phone in the fs_head list and duplicate it.  The duplicate
  293.      * phone will be returned to the client and the client will use it for
  294.      * communication.  In the future, we should cache the connections so
  295.      * that they do not have to be reestablished over and over again.
  296.      */
  297.     fibril_mutex_lock(&fs_head_lock);
  298.     link_t *cur;
  299.     fs_info_t *fs;
  300.     for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
  301.         fs = list_get_instance(cur, fs_info_t, fs_link);
  302.         if (fs->fs_handle == handle) {
  303.             fibril_mutex_unlock(&fs_head_lock);
  304.             fibril_mutex_lock(&fs->phone_lock);
  305.             phone = ipc_connect_me_to(fs->phone, 0, 0, 0);
  306.             fibril_mutex_unlock(&fs->phone_lock);
  307.  
  308.             assert(phone > 0);
  309.             return phone;
  310.         }
  311.     }
  312.     fibril_mutex_unlock(&fs_head_lock);
  313.     return 0;
  314. }
  315.  
  316. /** Tell VFS that the phone is not needed anymore.
  317.  *
  318.  * @param phone     Phone to FS task.
  319.  */
  320. void vfs_release_phone(int phone)
  321. {
  322.     /* TODO: implement connection caching */
  323.     ipc_hangup(phone);
  324. }
  325.  
  326. /** Convert file system name to its handle.
  327.  *
  328.  * @param name      File system name.
  329.  * @param lock      If true, the function will lock and unlock the
  330.  *          fs_head_lock.
  331.  *
  332.  * @return      File system handle or zero if file system not found.
  333.  */
  334. fs_handle_t fs_name_to_handle(char *name, bool lock)
  335. {
  336.     int handle = 0;
  337.    
  338.     if (lock)
  339.         fibril_mutex_lock(&fs_head_lock);
  340.     link_t *cur;
  341.     for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
  342.         fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);
  343.         if (str_cmp(fs->vfs_info.name, name) == 0) {
  344.             handle = fs->fs_handle;
  345.             break;
  346.         }
  347.     }
  348.     if (lock)
  349.         fibril_mutex_unlock(&fs_head_lock);
  350.     return handle;
  351. }
  352.  
  353. /**
  354.  * @}
  355.  */
  356.