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/*
* Copyright (c) 2006 Martin Decky
* 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 tmpfs.c
* @brief File system driver for in-memory file system.
*
* Every instance of tmpfs exists purely in memory and has neither a disk layout
* nor any permanent storage (e.g. disk blocks). With each system reboot, data
* stored in a tmpfs file system is lost.
*/
#include "tmpfs.h"
#include <ipc/ipc.h>
#include <ipc/services.h>
#include <async.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <libfs.h>
#include "../../vfs/vfs.h"
#define NAME "tmpfs"
vfs_info_t tmpfs_vfs_info = {
.name = "tmpfs",
};
fs_reg_t tmpfs_reg;
/**
* 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 TMPFS 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. Similarily, TMPFS 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, TMPFS might want to keep the connections open after the
* request has been completed.
*/
static void tmpfs_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_0(iid, EOK);
}
dprintf("VFS-TMPFS connection established.\n");
while (1) {
ipc_callid_t callid;
ipc_call_t call;
callid = async_get_call(&call);
switch (IPC_GET_METHOD(call)) {
case IPC_M_PHONE_HUNGUP:
return;
case VFS_OUT_MOUNTED:
tmpfs_mounted(callid, &call);
break;
case VFS_OUT_MOUNT:
tmpfs_mount(callid, &call);
break;
case VFS_OUT_LOOKUP:
tmpfs_lookup(callid, &call);
break;
case VFS_OUT_READ:
tmpfs_read(callid, &call);
break;
case VFS_OUT_WRITE:
tmpfs_write(callid, &call);
break;
case VFS_OUT_TRUNCATE:
tmpfs_truncate(callid, &call);
break;
case VFS_OUT_CLOSE:
tmpfs_close(callid, &call);
break;
case VFS_OUT_DESTROY:
tmpfs_destroy(callid, &call);
break;
case VFS_OUT_OPEN_NODE:
tmpfs_open_node(callid, &call);
break;
case VFS_OUT_STAT:
tmpfs_stat(callid, &call);
break;
case VFS_OUT_SYNC:
tmpfs_sync(callid, &call);
break;
default:
ipc_answer_0(callid, ENOTSUP);
break;
}
}
}
int main(int argc, char **argv)
{
printf(NAME ": HelenOS TMPFS file system server\n");
if (!tmpfs_init()) {
printf(NAME ": failed to initialize TMPFS\n");
return -1;
}
int vfs_phone = ipc_connect_me_to_blocking(PHONE_NS, SERVICE_VFS, 0, 0);
if (vfs_phone < EOK) {
printf(NAME ": Unable to connect to VFS\n");
return -1;
}
int rc = fs_register(vfs_phone, &tmpfs_reg, &tmpfs_vfs_info,
tmpfs_connection);
if (rc != EOK) {
printf(NAME ": Failed to register file system (%d)\n", rc);
return rc;
}
printf(NAME ": Accepting connections\n");
async_manager();
/* not reached */
return 0;
}
/**
* @}
*/
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