WebSVN – HelenOS – Blame – /branches/dynload/uspace/srv/fs/tmpfs/tmpfs.c

Rev	Author	Line No.	Line
2645	jermar	1	/*
		2	* Copyright (c) 2006 Martin Decky
2690	jermar	3	* Copyright (c) 2008 Jakub Jermar
2645	jermar	4	* All rights reserved.
		5	*
		6	* Redistribution and use in source and binary forms, with or without
		7	* modification, are permitted provided that the following conditions
		8	* are met:
		9	*
		10	* - Redistributions of source code must retain the above copyright
		11	* notice, this list of conditions and the following disclaimer.
		12	* - Redistributions in binary form must reproduce the above copyright
		13	* notice, this list of conditions and the following disclaimer in the
		14	* documentation and/or other materials provided with the distribution.
		15	* - The name of the author may not be used to endorse or promote products
		16	* derived from this software without specific prior written permission.
		17	*
		18	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
		19	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
		20	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
		21	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
		22	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
		23	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
		24	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
		25	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
		26	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
		27	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
		28	*/
		29
		30	/** @addtogroup fs
		31	* @{
		32	*/
		33
		34	/**
		35	* @file tmpfs.c
		36	* @brief File system driver for in-memory file system.
		37	*
		38	* Every instance of tmpfs exists purely in memory and has neither a disk layout
		39	* nor any permanent storage (e.g. disk blocks). With each system reboot, data
		40	* stored in a tmpfs file system is lost.
		41	*/
		42
		43	#include "tmpfs.h"
		44	#include <ipc/ipc.h>
		45	#include <ipc/services.h>
		46	#include <async.h>
		47	#include <errno.h>
		48	#include <unistd.h>
		49	#include <stdio.h>
		50	#include <libfs.h>
		51	#include "../../vfs/vfs.h"
		52
3150	svoboda	53	#define NAME "tmpfs"
2645	jermar	54
3150	svoboda	55
2645	jermar	56	vfs_info_t tmpfs_vfs_info = {
		57	.name = "tmpfs",
		58	};
		59
		60	fs_reg_t tmpfs_reg;
		61
		62	/**
		63	* This connection fibril processes VFS requests from VFS.
		64	*
		65	* In order to support simultaneous VFS requests, our design is as follows.
		66	* The connection fibril accepts VFS requests from VFS. If there is only one
		67	* instance of the fibril, VFS will need to serialize all VFS requests it sends
		68	* to FAT. To overcome this bottleneck, VFS can send TMPFS the
		69	* IPC_M_CONNECT_ME_TO call. In that case, a new connection fibril will be
		70	* created, which in turn will accept the call. Thus, a new phone will be
		71	* opened for VFS.
		72	*
		73	* There are few issues with this arrangement. First, VFS can run out of
		74	* available phones. In that case, VFS can close some other phones or use one
		75	* phone for more serialized requests. Similarily, TMPFS can refuse to duplicate
		76	* the connection. VFS should then just make use of already existing phones and
		77	* route its requests through them. To avoid paying the fibril creation price
		78	* upon each request, TMPFS might want to keep the connections open after the
		79	* request has been completed.
		80	*/
		81	static void tmpfs_connection(ipc_callid_t iid, ipc_call_t *icall)
		82	{
		83	if (iid) {
		84	/*
		85	* This only happens for connections opened by
		86	* IPC_M_CONNECT_ME_TO calls as opposed to callback connections
		87	* created by IPC_M_CONNECT_TO_ME.
		88	*/
		89	ipc_answer_0(iid, EOK);
		90	}
		91
		92	dprintf("VFS-TMPFS connection established.\n");
		93	while (1) {
		94	ipc_callid_t callid;
		95	ipc_call_t call;
		96
		97	callid = async_get_call(&call);
		98	switch (IPC_GET_METHOD(call)) {
3153	svoboda	99	case VFS_MOUNTED:
		100	tmpfs_mounted(callid, &call);
		101	break;
3009	svoboda	102	case VFS_MOUNT:
		103	tmpfs_mount(callid, &call);
		104	break;
2645	jermar	105	case VFS_LOOKUP:
		106	tmpfs_lookup(callid, &call);
		107	break;
2658	jermar	108	case VFS_READ:
		109	tmpfs_read(callid, &call);
		110	break;
2710	jermar	111	case VFS_WRITE:
		112	tmpfs_write(callid, &call);
		113	break;
2731	jermar	114	case VFS_TRUNCATE:
		115	tmpfs_truncate(callid, &call);
		116	break;
2742	jermar	117	case VFS_DESTROY:
		118	tmpfs_destroy(callid, &call);
2731	jermar	119	break;
2645	jermar	120	default:
		121	ipc_answer_0(callid, ENOTSUP);
		122	break;
		123	}
		124	}
		125	}
		126
		127	int main(int argc, char **argv)
		128	{
3150	svoboda	129	printf(NAME ": HelenOS TMPFS file system server\n");
4345	svoboda	130
		131	int vfs_phone = ipc_connect_me_to_blocking(PHONE_NS, SERVICE_VFS, 0, 0);
		132	if (vfs_phone < EOK) {
		133	printf(NAME ": Unable to connect to VFS\n");
		134	return -1;
2645	jermar	135	}
		136
4345	svoboda	137	int rc = fs_register(vfs_phone, &tmpfs_reg, &tmpfs_vfs_info,
2645	jermar	138	tmpfs_connection);
		139	if (rc != EOK) {
3150	svoboda	140	printf(NAME ": Failed to register file system (%d)\n", rc);
2645	jermar	141	return rc;
		142	}
		143
3150	svoboda	144	printf(NAME ": Accepting connections\n");
2645	jermar	145	async_manager();
		146	/* not reached */
		147	return 0;
		148	}
		149
		150	/**
		151	* @}
		152	*/

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