WebSVN – HelenOS – Blame – /trunk/uspace/srv/vfs/vfs_mount.c

Rev	Author	Line No.	Line
2542	jermar	1	/*
		2	* Copyright (c) 2007 Jakub Jermar
		3	* All rights reserved.
		4	*
		5	* Redistribution and use in source and binary forms, with or without
		6	* modification, are permitted provided that the following conditions
		7	* are met:
		8	*
		9	* - Redistributions of source code must retain the above copyright
		10	* notice, this list of conditions and the following disclaimer.
		11	* - Redistributions in binary form must reproduce the above copyright
		12	* notice, this list of conditions and the following disclaimer in the
		13	* documentation and/or other materials provided with the distribution.
		14	* - The name of the author may not be used to endorse or promote products
		15	* derived from this software without specific prior written permission.
		16	*
		17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
		18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
		19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
		20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
		21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
		22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
		23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
		24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
		25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
		26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
		27	*/
		28
		29	/** @addtogroup fs
		30	* @{
		31	*/
		32
		33	/**
		34	* @file vfs.c
		35	* @brief VFS_MOUNT method.
		36	*/
		37
		38	#include <ipc/ipc.h>
		39	#include <async.h>
		40	#include <errno.h>
		41	#include <stdlib.h>
		42	#include <string.h>
		43	#include <bool.h>
		44	#include <futex.h>
		45	#include <libadt/list.h>
		46	#include "vfs.h"
		47
2553	jermar	48	atomic_t rootfs_futex = FUTEX_INITIALIZER;
2587	jermar	49	vfs_triplet_t rootfs = {
		50	.fs_handle = 0,
		51	.dev_handle = 0,
		52	.index = 0,
		53	};
2542	jermar	54
2587	jermar	55	static int lookup_root(int fs_handle, int dev_handle, vfs_triplet_t *root)
2552	jermar	56	{
2587	jermar	57	vfs_pair_t altroot = {
2552	jermar	58	.fs_handle = fs_handle,
		59	.dev_handle = dev_handle,
		60	};
		61
2553	jermar	62	return vfs_lookup_internal("/", strlen("/"), root, &altroot);
2552	jermar	63	}
		64
2542	jermar	65	void vfs_mount(ipc_callid_t rid, ipc_call_t *request)
		66	{
2552	jermar	67	int dev_handle;
		68
		69	/*
		70	* We expect the library to do the device-name to device-handle
		71	* translation for us, thus the device handle will arrive as ARG1
		72	* in the request.
		73	*/
		74	dev_handle = IPC_GET_ARG1(*request);
		75
		76	/*
		77	* For now, don't make use of ARG2 and ARG3, but they can be used to
		78	* carry mount options in the future.
		79	*/
		80
		81	/*
		82	* Now, we expect the client to send us data with the name of the file
		83	* system and the path of the mountpoint.
		84	*/
		85	ipc_callid_t callid;
		86	ipc_call_t call;
		87	size_t size;
		88	if (!ipc_data_receive(&callid, &call, NULL, &size)) {
2588	jermar	89	ipc_answer_fast_0(callid, EINVAL);
		90	ipc_answer_fast_0(rid, EINVAL);
2552	jermar	91	return;
		92	}
		93
		94	/*
		95	* There is no sense in receiving data that can't hold a single
		96	* character of path. We won't accept data that exceed certain limits
		97	* either.
		98	*/
		99	if ((size < FS_NAME_MAXLEN + 1) \|\|
		100	(size > FS_NAME_MAXLEN + MAX_PATH_LEN)) {
2588	jermar	101	ipc_answer_fast_0(callid, EINVAL);
		102	ipc_answer_fast_0(rid, EINVAL);
2552	jermar	103	return;
		104	}
		105
		106	/*
		107	* Allocate buffer for the data being received.
		108	*/
		109	uint8_t *buf;
		110	buf = malloc(size);
		111	if (!buf) {
2588	jermar	112	ipc_answer_fast_0(callid, ENOMEM);
		113	ipc_answer_fast_0(rid, ENOMEM);
2552	jermar	114	return;
		115	}
		116
		117	/*
		118	* Deliver the data.
		119	*/
		120	(void) ipc_data_deliver(callid, &call, buf, size);
		121
		122	char fs_name[FS_NAME_MAXLEN + 1];
		123	memcpy(fs_name, buf, FS_NAME_MAXLEN);
		124	fs_name[FS_NAME_MAXLEN] = '\0';
		125
		126	/*
		127	* Check if we know a file system with the same name as is in fs_name.
		128	* This will also give us its file system handle.
		129	*/
		130	int fs_handle = fs_name_to_handle(fs_name, true);
		131	if (!fs_handle) {
		132	free(buf);
2588	jermar	133	ipc_answer_fast_0(rid, ENOENT);
2552	jermar	134	return;
		135	}
		136
		137	/*
		138	* Lookup the root node of the filesystem being mounted.
		139	*/
		140	int rc;
2587	jermar	141	vfs_triplet_t mounted_root;
2552	jermar	142	rc = lookup_root(fs_handle, dev_handle, &mounted_root);
		143	if (rc != EOK) {
		144	free(buf);
2588	jermar	145	ipc_answer_fast_0(rid, rc);
2552	jermar	146	return;
		147	}
		148
		149	/*
		150	* Finally, we need to resolve the path to the mountpoint.
		151	*/
2587	jermar	152	vfs_triplet_t mp;
2553	jermar	153	futex_down(&rootfs_futex);
2552	jermar	154	if (rootfs.fs_handle) {
		155	/*
		156	* We already have the root FS.
		157	*/
		158	rc = vfs_lookup_internal((char *) (buf + FS_NAME_MAXLEN),
		159	size - FS_NAME_MAXLEN, &mp, NULL);
		160	if (rc != EOK) {
		161	/*
		162	* The lookup failed for some reason.
		163	*/
2553	jermar	164	futex_up(&rootfs_futex);
2552	jermar	165	free(buf);
2588	jermar	166	ipc_answer_fast_0(rid, rc);
2552	jermar	167	return;
		168	}
		169	} else {
		170	/*
		171	* We still don't have the root file system mounted.
		172	*/
2553	jermar	173	if ((size - FS_NAME_MAXLEN == strlen("/")) &&
2552	jermar	174	(buf[FS_NAME_MAXLEN] == '/')) {
		175	/*
		176	* For this simple, but important case, we are done.
		177	*/
		178	rootfs = mounted_root;
2553	jermar	179	futex_up(&rootfs_futex);
2552	jermar	180	free(buf);
2588	jermar	181	ipc_answer_fast_0(rid, EOK);
2552	jermar	182	return;
		183	} else {
		184	/*
		185	* We can't resolve this without the root filesystem
		186	* being mounted first.
		187	*/
2553	jermar	188	futex_up(&rootfs_futex);
2552	jermar	189	free(buf);
2588	jermar	190	ipc_answer_fast_0(rid, ENOENT);
2552	jermar	191	return;
		192	}
		193	}
2553	jermar	194	futex_up(&rootfs_futex);
		195
2554	jermar	196	free(buf); /* The buffer is not needed anymore. */
		197
2552	jermar	198	/*
		199	* At this point, we have all necessary pieces: file system and device
		200	* handles, and we know the mount point VFS node and also the root node
		201	* of the file system being mounted.
		202	*/
2554	jermar	203
		204	int phone = vfs_grab_phone(mp.fs_handle);
		205	/* Later we can use ARG3 to pass mode/flags. */
		206	aid_t req1 = async_send_3(phone, VFS_MOUNT, (ipcarg_t) mp.dev_handle,
		207	(ipcarg_t) mp.index, 0, NULL);
		208	/* The second call uses the same method. */
		209	aid_t req2 = async_send_3(phone, VFS_MOUNT,
		210	(ipcarg_t) mounted_root.fs_handle,
		211	(ipcarg_t) mounted_root.dev_handle, (ipcarg_t) mounted_root.index,
		212	NULL);
		213
		214	ipcarg_t rc1;
		215	ipcarg_t rc2;
		216	async_wait_for(req1, &rc1);
		217	async_wait_for(req2, &rc2);
		218	vfs_release_phone(phone);
		219
2569	jermar	220	if (rc2 == EOK)
2588	jermar	221	ipc_answer_fast_0(rid, rc1);
2569	jermar	222	else if (rc1 == EOK)
2588	jermar	223	ipc_answer_fast_0(rid, rc2);
2554	jermar	224	else
2588	jermar	225	ipc_answer_fast_0(rid, rc1);
2542	jermar	226	}
		227
		228	/**
		229	* @}
		230	*/

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(root)/trunk/uspace/srv/vfs/vfs_mount.c – Rev 2588