/*
* Copyright (c) 2006 Martin Decky
* Copyright (c) 2007 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 fat.c
* @brief FAT file system driver for HelenOS.
*/
#include <ipc/ipc.h>
#include <ipc/services.h>
#include <async.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include "../../vfs/vfs.h"
#define dprintf(...) printf(__VA_ARGS__)
vfs_info_t fat_vfs_info = {
.name = "fat",
.ops = {
[IPC_METHOD_TO_VFS_OP(VFS_REGISTER)] = VFS_OP_DEFINED,
[IPC_METHOD_TO_VFS_OP(VFS_MOUNT)] = VFS_OP_DEFINED,
[IPC_METHOD_TO_VFS_OP(VFS_UNMOUNT)] = VFS_OP_DEFINED,
[IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] = VFS_OP_DEFINED,
[IPC_METHOD_TO_VFS_OP(VFS_OPEN)] = VFS_OP_DEFINED,
[IPC_METHOD_TO_VFS_OP(VFS_CREATE)] = VFS_OP_DEFINED,
[IPC_METHOD_TO_VFS_OP(VFS_CLOSE)] = VFS_OP_DEFINED,
[IPC_METHOD_TO_VFS_OP(VFS_READ)] = VFS_OP_DEFINED,
[IPC_METHOD_TO_VFS_OP(VFS_WRITE)] = VFS_OP_NULL,
[IPC_METHOD_TO_VFS_OP(VFS_SEEK)] = VFS_OP_DEFAULT
}
};
/**
* This connection fibril processes VFS requests from VFS.
*
* In order to support simultaneous VFS requests, our design is as follows.
* The connection fibril accepts VFS requests from VFS. If there is only one
* instance of the fibril, VFS will need to serialize all VFS requests it sends
* to FAT. To overcome this bottleneck, VFS can send FAT the IPC_M_CONNECT_ME_TO
* call. In that case, a new connection fibril will be created, which in turn
* will accept the call. Thus, a new phone will be opened for VFS.
*
* There are few issues with this arrangement. First, VFS can run out of
* available phones. In that case, VFS can close some other phones or use one
* phone for more serialized requests. Similarly, FAT can refuse to duplicate
* the connection. VFS should then just make use of already existing phones and
* route its requests through them. To avoid paying the fibril creation price
* upon each request, FAT might want to keep the connections open after the
* request has been completed.
*/
static void fat_connection(ipc_callid_t iid, ipc_call_t *icall)
{
if (iid) {
/*
* This only happens for connections opened by
* IPC_M_CONNECT_ME_TO calls as opposed to callback connections
* created by IPC_M_CONNECT_TO_ME.
*/
ipc_answer_fast(iid, EOK, 0, 0);
}
dprintf("VFS-FAT connection established.\n");
while (1) {
ipc_callid_t callid;
ipc_call_t call;
callid = async_get_call(&call);
switch (IPC_GET_METHOD(call)) {
default:
ipc_answer_fast(callid, ENOTSUP, 0, 0);
break;
}
}
}
int main(int argc, char **argv)
{
int vfs_phone;
printf("FAT: HelenOS FAT file system server.\n");
vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0);
while (vfs_phone < EOK) {
usleep(10000);
vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0);
}
/*
* Tell VFS that we are here and want to get registered.
* We use the async framework because VFS will answer the request
* out-of-order, when it knows that the operation succeeded or failed.
*/
ipc_call_t answer;
aid_t req = async_send_2(vfs_phone, VFS_REGISTER, 0, 0, &answer);
/*
* Send our VFS info structure to VFS.
*/
int rc = ipc_data_send(vfs_phone, &fat_vfs_info, sizeof(fat_vfs_info));
if (rc != EOK) {
async_wait_for(req, NULL);
return rc;
}
/*
* Ask VFS for callback connection.
*/
ipcarg_t phonehash;
ipc_connect_to_me(vfs_phone, 0, 0, &phonehash);
/*
* Create a connection fibril to handle the callback connection.
*/
async_new_connection(phonehash, 0, NULL, fat_connection);
/*
* Tell the async framework that other connections are to be handled by
* the same connection fibril as well.
*/
async_set_client_connection(fat_connection);
/*
* Pick up the answer for the request to the VFS_REQUEST call.
*/
async_wait_for(req, NULL);
dprintf("FAT filesystem registered.\n");
async_create_manager();
/*
* TODO: Interestingly, if we merely return, the only thread dies.
* If the only thread dies, the whole task is destroyed.
* Prevent the thread from exiting when there are active fibrils.
*/
fibril_schedule_next_adv(FIBRIL_FROM_DEAD);
/* not reached */
return 0;
}
/**
* @}
*/