Subversion Repositories HelenOS

/*

 * 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	fat.c

 * @brief	FAT file system driver for HelenOS.

 */

#include "fat.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"

vfs_info_t fat_vfs_info = {

	.name = "fat",

};

fs_reg_t fat_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 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. Similarily, 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_0(iid, EOK);

	}

	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)) {

		case IPC_M_PHONE_HUNGUP:

			return;

		case VFS_OUT_MOUNTED:

			fat_mounted(callid, &call);

			break;

		case VFS_OUT_MOUNT:

			fat_mount(callid, &call);

			break;

		case VFS_OUT_LOOKUP:

			fat_lookup(callid, &call);

			break;

		case VFS_OUT_READ:

			fat_read(callid, &call);

			break;

		case VFS_OUT_WRITE:

			fat_write(callid, &call);

			break;

		case VFS_OUT_TRUNCATE:

			fat_truncate(callid, &call);

			break;

		case VFS_OUT_STAT:

			fat_stat(callid, &call);

			break;

		case VFS_OUT_CLOSE:

			fat_close(callid, &call);

			break;

		case VFS_OUT_DESTROY:

			fat_destroy(callid, &call);

			break;

		case VFS_OUT_OPEN_NODE:

			fat_open_node(callid, &call);

			break;

		case VFS_OUT_SYNC:

			fat_sync(callid, &call);

			break;

		default:

			ipc_answer_0(callid, ENOTSUP);

			break;

		}

	}

}

int main(int argc, char **argv)

{

	int vfs_phone;

	int rc;

	printf("fat: HelenOS FAT file system server.\n");

	rc = fat_idx_init();

	if (rc != EOK)

		goto err;

	vfs_phone = ipc_connect_me_to_blocking(PHONE_NS, SERVICE_VFS, 0, 0);

	if (vfs_phone < EOK) {

		printf("fat: failed to connect to VFS\n");

		return -1;

	}

	rc = fs_register(vfs_phone, &fat_reg, &fat_vfs_info, fat_connection);

	if (rc != EOK) {

		fat_idx_fini();

		goto err;

	}

	dprintf("FAT filesystem registered, fs_handle=%d.\n",

	    fat_reg.fs_handle);

	async_manager();

	/* not reached */

	return 0;

err:

	printf("Failed to register the FAT file system (%d)\n", rc);

	return rc;

}

/**

 * @}

 */