source: mainline/uspace/srv/vfs/vfs.c@ c08c355

/*
 * Copyright (c) 2008 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup fs
 * @{
 */

/**
 * @file vfs.c
 * @brief VFS service for HelenOS.
 */

#include <ipc/ipc.h>
#include <ipc/services.h>
#include <async.h>
#include <errno.h>
#include <stdio.h>
#include <bool.h>
#include <string.h>
#include <as.h>
#include <libadt/list.h>
#include <atomic.h>
#include "vfs.h"

#define NAME "vfs"

static void vfs_connection(ipc_callid_t iid, ipc_call_t *icall)
{
        bool keep_on_going = true;
        
        /*
         * The connection was opened via the IPC_CONNECT_ME_TO call.
         * This call needs to be answered.
         */
        ipc_answer_0(iid, EOK);
        
        /*
         * Here we enter the main connection fibril loop.
         * The logic behind this loop and the protocol is that we'd like to keep
         * each connection open until the client hangs up. When the client hangs
         * up, we will free its VFS state. The act of hanging up the connection
         * by the client is equivalent to client termination because we cannot
         * distinguish one from the other. On the other hand, the client can
         * hang up arbitrarily if it has no open files and reestablish the
         * connection later.
         */
        while (keep_on_going) {
                ipc_call_t call;
                ipc_callid_t callid = async_get_call(&call);
                
                fs_handle_t fs_handle;
                int phone;
                
                switch (IPC_GET_METHOD(call)) {
                case IPC_M_PHONE_HUNGUP:
                        keep_on_going = false;
                        break;
                case IPC_M_CONNECT_ME_TO:
                        /*
                         * Connect the client file system to another one.
                         */
                        /* FIXME:
                         * Prevent ordinary clients from connecting to file
                         * system servers directly. This should be solved by
                         * applying some security mechanisms.
                         */
                        fs_handle = IPC_GET_ARG1(call);
                        phone = vfs_grab_phone(fs_handle);
                        (void) ipc_forward_fast(callid, phone, 0, 0, 0,
                            IPC_FF_NONE);
                        vfs_release_phone(phone);
                        break;
                case VFS_REGISTER:
                        vfs_register(callid, &call);
                        /*
                         * Keep the connection open so that a file system can
                         * later ask us to connect it to another file system.
                         * This is necessary to support non-root mounts.
                         */
                        break;
                case VFS_MOUNT:
                        vfs_mount(callid, &call);
                        break;
                case VFS_OPEN:
                        vfs_open(callid, &call);
                        break;
                case VFS_CLOSE:
                        vfs_close(callid, &call);
                        break;
                case VFS_READ:
                        vfs_read(callid, &call);
                        break;
                case VFS_WRITE:
                        vfs_write(callid, &call);
                        break;
                case VFS_SEEK:
                        vfs_seek(callid, &call);
                        break;
                case VFS_TRUNCATE:
                        vfs_truncate(callid, &call);
                        break;
                case VFS_MKDIR:
                        vfs_mkdir(callid, &call);
                        break;
                case VFS_UNLINK:
                        vfs_unlink(callid, &call);
                        break;
                case VFS_RENAME:
                        vfs_rename(callid, &call);
                        break;
                default:
                        ipc_answer_0(callid, ENOTSUP);
                        break;
                }
        }
        
        /* TODO: cleanup after the client */
}

int main(int argc, char **argv)
{
        printf(NAME ": HelenOS VFS server\n");
        
        /*
         * Initialize the list of registered file systems.
         */
        list_initialize(&fs_head);
        
        /*
         * Initialize VFS node hash table.
         */
        if (!vfs_nodes_init()) {
                printf(NAME ": Failed to initialize VFS node hash table\n");
                return ENOMEM;
        }
        
        /*
         * Allocate and initialize the Path Lookup Buffer.
         */
        list_initialize(&plb_head);
        plb = as_get_mappable_page(PLB_SIZE);
        if (!plb) {
                printf(NAME ": Cannot allocate a mappable piece of address space\n");
                return ENOMEM;
        }
        
        if (as_area_create(plb, PLB_SIZE, AS_AREA_READ | AS_AREA_WRITE |
            AS_AREA_CACHEABLE) != plb) {
                printf(NAME ": Cannot create address space area\n");
                return ENOMEM;
        }
        memset(plb, 0, PLB_SIZE);
        
        /*
         * Set a connectio handling function/fibril.
         */
        async_set_client_connection(vfs_connection);
        
        /*
         * Register at the naming service.
         */
        ipcarg_t phonead;
        ipc_connect_to_me(PHONE_NS, SERVICE_VFS, 0, 0, &phonead);
        
        /*
         * Start accepting connections.
         */
        printf(NAME ": Accepting connections\n");
        async_manager();
        return 0;
}

/**
 * @}
 */